Bulgarian Chemical Communications, 56, SI D2, 96-99, 2024
Dandelion is a well-known edible and medicinal plant with numerous studies of its health benefits... more Dandelion is a well-known edible and medicinal plant with numerous studies of its health benefits. Interest presents its polyphenolic and carbohydrate composition and its non-polar components in the aerial parts and roots have been identified. There are no studies about the composition of the fatty acid phytocomponents in the flowers of the dandelion. The main purpose of the present study is a comparative investigation of n-hexane, ethanol, and n-hexane/ethanol (1:1 v/v) soluble compounds from dandelion flowers (Taraxacum officinale Weber ex F.H. Wigg.) collected during the flowering period. The GC-MS analysis of the non-polar (lipid) fractions showed the presence of 30 biologically active phytocompounds. The fatty acids predominated in the investigated extracts [(50-60 % of total ion current (TIC)], followed by triterpenes (9-11 % of TIC) and phytosterols (7-8 % of TIC). Polyunsaturated fatty acids-linoleic acid and α-linolenic acid (10-15 % of TIC) were identified as the major components. Phytosterols were mainly represented by β-sitosterol (3-4 % of TIC) and stigmasterol (above 2% of TIC), while pentacyclic triterpenes from cycloartenol 3-acetate (3-4% of TIC) and β-amyrin (above 2% of TIC) were found. Based on the fatty acid profile, the nutritional indices directly correlated with the lipid metabolites profile responsible for human health were calculated: Index of atherogenicity (IA)-1.2-1.6; Index of thrombogenicity (IT)-0,6-0,7; Hypocholesterolemic/hypercholesterolemic (HH) ratio-1.0-1.3; Health-promoting index (HPI)-0.6-0.8; Unsaturation index (UI)-72 and linoleic acid/α-linolenic acid (LA/ALA) ratio-1.1. The current results reveal the nutritional potential and health benefits of edible dandelion flowers.
Carlina acanthifolia All. is widely used in traditional medicine due to the presence of essential... more Carlina acanthifolia All. is widely used in traditional medicine due to the presence of essential oil (1-2%) in the outer part of the roots of the plant. It is mainly used for its choleretic and anti-inflammatory properties, as well as for the treatment of gastrointestinal problems. We obtain the fractions by sequential extraction with different solvents (hexane, chloroform, ethyl acetate, and ethanol) from carline thistles (Carlina acanthifolia All.) roots, evaluate the phytochemical compounds and for the first time, we report here the 3D fluorescence excitation-emission spectra. High extractable contents of fatty acids, terpenes, sterols, sugars and polyphenols, flavonoids and carlina oxide were found in the different fractional extracts of Carlina acanthifolia root. Three phenolic acids were detected in the ethyl acetate and n-hexane fraction, benzoic acid, phenylacetic acid, and p-methoxymadelic acid. In addition, fatty acids, pentacyclic triterpenes and sugars have been identified, these phytocomponents are responsible for the fluorescent properties of the roots. The topographic view of the excitation-emission matrix outlines a large strong first maximum (em,1 = 570 nm for exc,1 = 470 nm) connected with the presence of vitamin E and fatty acids and a weaker narrower second one (em,2 = 465 nm for exc,2 = 360 nm), witch is due to the presence of flavonoids, phenolic acids and palmitic acid. The emission spectrum of the main maximum is rather large at the 90% level (em,1 = 60 nm) but is observed over a narrow excitation bandwidth (exm,1 = 25 nm). The Stokes shift Δ is around 100 nm over the excitation range from 430 to 560 nm. Seven elements-Ca, Fe, K, Mg, Mn, Na and Zn, were determined in Carlina acanthifolia All. as potassium has the highest content K = 32.7 ± 0.6 g kg −1 followed by Ca, Mg and Fe (8.24 ± 0.12;1.86 ± 0.03;1.25 ± 0.01 g kg −1) , in mg kg −1 are Na = 212 ± 3 , Mn = 41.9 ± 0.2 and Zn = 26.7 ± 0.3.
The development of functional foods providing health benefits above the basic nutritional needs i... more The development of functional foods providing health benefits above the basic nutritional needs is of growing interest to the food industry. This research aimed to: design fresh prebiotic cheese spreads enriched with agave inulin (AI), thyme (Thymus callieri Borbás ex Velen.) and hawthorn fruit (Crataegus monogyna Jacq.) as plant sources of biologically active compounds; observe the physicochemical and microbiological changes in the cheese during storage at 4°C for 35 days; evaluate the sensory characteristics of the new functional products. Therefore, five experimental groups of fresh cheese spreads were prepareda control; 1% AI + 0.2% thyme; 2% AI + 0.2% thyme; 1% AI + 0.4% hawthorn fruit and 2% AI + 0.4% hawthorn fruit. During the storage, pH in all experimental groups gradually decreased (reaching values between 4.17 and 4.25 on the 35 th day), which corresponded to the increasing titratable acidity (reaching values from 146.30°T to 152.51°T on the 35 th day). The application of thyme and hawthorn fruit did not reduce the total plate count (mesophilic aerobic and facultative anaerobic microorganisms) and yeasts; however, during the storage period the addition of agave inulin stimulated the growth of lactic acid bacteria in the treated samples compared to the control.
The development of functional foods providing health benefits above the basic nutritional needs i... more The development of functional foods providing health benefits above the basic nutritional needs is of great interest to the food industry. This research aimed to: design functional yogurts with agave inulin and extracts from propolis, rose petals and Spirulina platensis; observe the physicochemical and microbiological changes during storage at 4°C for 21 days; evaluate the sensory characteristics of the new functional products. Three kinds of calcium alginate microcapsules (agave inulin + ethanolic propolis extract; agave inulin + ethanolic propolis extract + rose petals extract; agave inulin + ethanolic propolis extract + Spirulina extract) were prepared and applied in yogurts before the coagulation. During the storage, pH in all experimental groups gradually decreased (reaching values between 3.94 and 4.02 on the 21 st day), which corresponded to the increasing titratable acidity (reaching values from 94.17°T to 108.78°T on the 21 st day). The application of microcapsules did not affect the coagulation process and number of lactic acid bacteria in yogurts until the end of storage period. To the best of our knowledge, this is the first study to investigate the application of agave inulin, propolis, rose petals and S. platensis extracts in microencapsulated form in traditional Bulgarian yogurt in order to obtain a dairy product with enhanced functional properties.
The aim of the present study was to evaluate and compare three types of lavender (Lavandula angus... more The aim of the present study was to evaluate and compare three types of lavender (Lavandula angustifolia Mill.) biomasses for their content of biologically active substances and potential application. The first one was from unprocessed lavender (L-UNTR22_Z) and the other two were industrial steam-distilled lavender solid residues (L-SD22_Z and L-SD22_M). Ash, protein, polyuronide content and the degree of esterification of the pectic substances in the biomass were investigated. 70% ethanolic extracts of the residues were prepared and their total polyphenol content and antioxidant activity were evaluated by four methods. Individual phenolic acids, flavonoids, polar non-volatile compounds and polar volatile compounds were also determined by chromatographic analyses. The highest degree of esterification (83.9±0.5%) and protein content (8.15±1.6%) were found in L-SD22_Z extract. L-SD22_M extract demonstrated the highest polyphenolic content and antioxidant activity. Six phenolic acids (protocatehuic, syringic, p-coumaric, ferulic, salicylic, and gallic acid) and five flavonoids ((+)-catechin, (-)-epicatechin, rutin, hesperidin, and quercetin) were detected by HPLC analyses. The detail information about amino acids, sugars, organic and phenolic acids, as well as polar volatile compounds was obtained by GC-MS. The results suggested that the lavender (untreated and residual biomass) are a good source of dietary antioxidants and compounds with potent biological activity.
Functional foods and beverages can be defined as processed products that provide health benefits ... more Functional foods and beverages can be defined as processed products that provide health benefits beyond the basic nutritional needs and reduce the risk of diseases. The design of functional products with improved shelf-life is a new challenge for the food industry. Therefore, this research aimed to: design a functional fruit-herbal beverage; compare the preservation effect of two preservatives (propolis extract and potassium sorbate) added in the beverages; evaluate the sensory characteristics of the newly designed beverages; observe the physico-chemical and microbiological changes during storage at 4℃ for 42 d. The results demonstrated that the addition of propolis extract (0.02%) in the beverage, increased the total polyphenols, total flavonoids and antioxidant activity, compared to the control beverage and the beverage containing potassium sorbate (0.05%). The results from microbiological analyses showed that potassium sorbate and propolis extract effectively inhibited the microbial growth in the treated beverages. However, the propolis extract in a lower concentration (0.02%) was as effective as potassium sorbate in a higher concentration (0.05%) during the entire storage period. Consequently, in addition to being a functional ingredient and a food enhancer, propolis is a prospective natural preservative, which can improve the shelf-life of the food products and beverages.
Propolis is a natural mixture of resins, wax, and pollen from plant buds and flowers, enriched wi... more Propolis is a natural mixture of resins, wax, and pollen from plant buds and flowers, enriched with enzymes and bee saliva. It also contains various essential oils, vitamins, mineral salts, trace elements, hormones, and ferments. It has been found that propolis possesses antimicrobial, antiviral, and anti-inflammatory properties. We have studied the antiviral activity of six extracts of Bulgarian propolis collected from six districts of Bulgaria. The study was conducted against structurally different viruses: human coronavirus strain OC-43 (HCoV OC-43) and human respiratory syncytial virus type 2 (HRSV-2) (enveloped RNA viruses), human herpes simplex virus type 1 (HSV-1) (enveloped DNA virus), human rhinovirus type 14 (HRV-14) (non-enveloped RNA virus) and human adenovirus type 5 (HadV-5) (non-enveloped DNA virus). The influence of the extracts on the internal replicative cycle of viruses was determined using the cytopathic effect (CPE) inhibition test. The virucidal activity, its impact on the stage of viral adsorption to the host cell, and its protective effect on healthy cells were evaluated using the final dilution method, making them the focal points of interest. The change in viral infectivity under the action of propolis extracts was compared with untreated controls, and Δlgs were determined. Most propolis samples administered during the viral replicative cycle demonstrated the strongest activity against HCoV OC-43 replication. The influence of propolis extracts on the viability of extracellular virions was expressed to a different degree in the various viruses studied, and the effect was significantly stronger in those with an envelope. Almost all extracts significantly inhibited the adsorption step of the herpes virus and, to a less extent, of the coronavirus to the host cell, and some of them applied before viral infection demonstrated a protective effect on healthy cells. Our results enlarge the knowledge about the action of propolis and could open new perspectives for its application in viral infection treatment.
Propolis (bee glue), a valuable biological mixture produced by European honey bees (Apis mellifer... more Propolis (bee glue), a valuable biological mixture produced by European honey bees (Apis mellifera L.), is widely used as a remedy in traditional and alternative medicine, as an effective food biopreservative and as a nutritional value enhancer. The present study aimed to investigate eighty propolis samples collected from all twenty-eight districts of Bulgaria in the period of 2020-2022 in order to determine their physicochemical properties as well as their antioxidant and antimicrobial potential. The raw propolis samples exhibited brown or green colour depending on the climatic zone from which they are collected and pH values from 4.82 to 5.87, while the moisture content ranged between 0.98% and 2.97%. The total phenolics content (TPC) and total flavonoids content (TFC) varied from 63.14 mg GAE/g to 737.27 mg GAE/g, and from 29.22 mg QE/g to 234.17 mg QE/g, respectively. The propolis samples demonstrated significant antioxidant potential determined by DPPH and FRAP methods, from 18.56 mM TE/g to 1598.66 mM TE/g and from 82.28 mM TE/g to 1208.81 mM TE/g, respectively, whose values showed a positive correlation (r 2) with the TPC and TFC. The results from the antimicrobial screening revealed that the methanolic propolis extracts in concentration of 20 mg/ml exhibited the highest inhibitory effect on the Gram-positive bacteria such as Micrococcus luteus 2YC-YT, Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 25923, Listeria monocytogenes NBIMCC 8632 and Listeria innocua ATCC 33090.
Tropical Journal of Natural Product Research, 2023
It is known that plants from the Carlina genus possessed many biological activity due to the bioa... more It is known that plants from the Carlina genus possessed many biological activity due to the bioactive compounds. The current study investigates the phytochemical constituents and antioxidant potential of the different vegetal parts of Carlina vulgaris L., Carlina acanthifolia All. and Carlina corymbosa L. The samples (roots and aerial part) were collected from Bulgaria (Golo Bardo and Vlahina mountains). Total phenols, flavonoids, individual phenolic compounds, triterpenes, phytosterols, carlina oxide, fructans, and individual sugars were determined. Antioxidant potential was evaluated using four methods. The highest total phenolic content was found in ethanol extract from C. acantifololia All. roots. Three phenolic acids (chlorogenic acid, ferulic acid, and salicylic acid), three flavonoids (rutin, hesperidin, and quercetin), and triterpenes (lupeol and betulin) were detected in all samples (mainly in roots). However, p-coumaric acid and ursolic acid were detected only in C. vulgaris, while carlina oxide was found only in C. acantifololia All. roots. The result showed that the roots of C. acanthifolia All. were characterized by appreciable amounts of total fructans (20 g/100 g dry weight), while inulin represented 18-12 g/100 g of dry weight. Sugars were found in all plant materials. The current study provides data about the chemical composition of extracts obtained from three members of the Carlina genus and their use as a source of antioxidants, phenolic compounds, carlina oxide, and inulin-type prebiotics.
Trop J Nat Prod Res, July 2022; 6(7):1113-1118, 2022
Mentioned for the first time in the Materia medica by Pedanios Dioscorides, Sideritis scardica ha... more Mentioned for the first time in the Materia medica by Pedanios Dioscorides, Sideritis scardica has been well known for its prolific anti-inflammatory properties for centuries. The name derives from the Greek word "sideros", meaning iron. Ancient soldiers used the plant to help the healing process of cut wounds caused by iron weapons. The European Medical Agency Committee on Herbal Medicinal Products points to its traditional use for the relief of cough, associated with cold and gastrointestinal disorders. 1 Other described biological activities of the herb include anti-glioma, cytotoxic, antimicrobial, and antirheumatic. 2-5 Belonging to the Lamiaceae Family, Sideritis scardica has become more popular outside the Balkan Peninsula in the last decades. Different studies have confirmed its positive effect on cognitive and neurodegenerative diseases. 6-8 The phytochemical profile of the plant reveals many polyphenolic compoundsphenylethanoid glycosides, acetylated and nonacetylated flavonoids, and several organic phenolic acids. 2,3,9,10 With this composition, preparations from Sideritis scardica and other herbs belonging to the same genus in the Mediterranean display prominent antioxidant activity. Oxidative stress has long been linked with neurodegenerative processes, whether as a cause or part of a pathological cascade induced by other factors.
Burdock (Arctium lappa L.) roots were used as a medicinal plant or vegetable worldwide. The resea... more Burdock (Arctium lappa L.) roots were used as a medicinal plant or vegetable worldwide. The research aimed to obtain different fractions by sequential extraction (hexane, chloroform, ethyl acetate water) of burdock roots and to evaluate phytochemical compounds in them. Antioxidant and antimicrobial properties of nonpolar fractions were evaluated. Ethyl acetate fraction contained the highest total phenolics, total flavonoids, and derivatives of caffeic acids. Phenolic acids (mainly chlorogenic, caffeic acid, and p-coumaric acids) were detected only in the ethyl acetate fraction, while in the hexane fraction was found only triterpenes. Due to the high polyphenol content, the ethyl acetate fraction demonstrated the highest antioxidant activity. Three fractions revealed antimicrobial activity against Salmonella sp., Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Proteus vulgaris, Staphylococcus aureus, Bacillus cereus, and Candida albicans. The lowest minimum inhibitory concentration (>1 mg/ml) showed an ethyl acetate fraction against Pseudomonas aeruginosa and Bacillus cereus. From the water fraction was isolated inulin-type fructan with a degree of polymerization 20-24 with promising functional properties. This study showed the potential application of burdock root fractions as a rich source of phytochemicals with antimicrobial, antioxidant activities, and potential prebiotic effect due to the 7 g/100 g inulin content in them.
The task of this study was to perform the "green" synthesis of lactose octaacetate through microw... more The task of this study was to perform the "green" synthesis of lactose octaacetate through microwave irradiation and to establish their biological activities. Lactose ester was prepared after microwave-assisted esterification of lactose with acetic anhydride (yield 85-90 %). Lactose octaacetate was characterized by a high degree of acetylation (DS 3.2-3.7). The lactose esters' structure was elucidated by infrared spectroscopy and nuclear magnetic resonance spectroscopy. Lactose octaacetate showed better antifungal activities than antibacterial activities. It possessed slight to moderate antifungal activities against Aspergillus niger ATCC 1015, Penicillium sp., Rhizopus sp., Fusarium moniliforme ATCC 38932. Lactose acetates demonstrated low cytotoxicity against three cell lines: Madin-Darby bovine kidney (MDBK) cells, human epithelial type 2 (HEp-2), and Madin-Darby canine kidney (MDCK) cells. This is the first report for antiviral activity of lactose acetates against herpes simplex virus type 1 (HSV-1), influenza virus A/Panama/2007/99/H3N2-(IAV/H3N2), PV-1 and Coxsackievirus B1. It was found that this compound showed activity with SI = 2.4 only against PV-1, but against HSV-1, IAV/H3N2, and Coxsackievirus B1 was inactive. The current study demonstrated the applications of lactose acetates as antimicrobial and antiviral substances in food, pharmaceutical, agricultural and cosmetic preparations.
In the present work, ice cream mixtures with 5%, 10% and 15% lingonberry extract were studied. Th... more In the present work, ice cream mixtures with 5%, 10% and 15% lingonberry extract were studied. The lingonberry (Vaccinium vitis-idaea L.) is a source of anthocyanins and flavonoids, which are the bioactive components with good antioxidant properties. There was a significant increase in antioxidant activity (p<0.05) from 133.3 ± 5.6 mM TE/100 g to 249.8 ± 8.3 mM TE/100 g (ABTS method) with increasing the concentration of the extract from 5% to 15%, respectively. Significant changes (p<0.05) in the acidity and dry matter of the samples with lingonberry extract were recorded. After 30 days of storage, a decrease in the antioxidant properties (p<0.05) of the ice cream samples was observed but higher values (mM TE/100 g) were maintained compared to the sample without extract. The color characteristics of the samples were also influenced by the concentration of the extract used. During storage, the highest stability of the colorimetric index a* (red component) was established, which indicates relative color stability during storage.
Current Research in Nutrition and Food Science, 2022
Propolis is a complex honey bee product known for its antioxidant potential and antimicrobial act... more Propolis is a complex honey bee product known for its antioxidant potential and antimicrobial activity, widely used as a food biopreservative and food additive. The object of the current research was to investigate the effects of carboxymethyl cellulose (CMC) edible coatings applied alone and in combination with a propolis extract on the quality parameters and storage life of fresh blueberries during refrigerated storage for 20 days. For this purpose, three experimental groups were prepared: blueberries without coating (control group), blueberries with 1%CMC coatings and blueberries with 1% CMC coatings+1% propolis extract (CMC+P). During the storage, the physicochemical and microbiological parameters of the experimental groups were evaluated. The use of CMC and CMC+P coatings reduced the weight loss by 1.13% and 1.67% in comparison with the control group on the 20-th day of storage. A significant decrease in decay percentage was found, which was in the great extent in the CMC+P coated fruit compared to the CMC coatings and the control fruit. The CMC and CMC+P edible coatings did not affect the TSS levels, the decreasing TA and increasing pH values. The application of CMC and CMC+P coatings did not cause a protective effect on the lowering values of total phenolic and anthocyanin contents in both treatments, but exhibited a positive influence on the antioxidant activity in CONTACT Yulian Dimitrov Tumbarski
Доклади на Българската академия на науките Comptes rendus de l’Acad´emie bulgare des Sciences, 74, No 12, 2021
Bilberries (Vaccinium myrtillus L.) belong to the Ericaceae family and have been traditionally us... more Bilberries (Vaccinium myrtillus L.) belong to the Ericaceae family and have been traditionally used in folk medicine for centuries because of their high content of polyphenolic compounds. Berry polyphenols exhibit strong antioxidant properties that could have preventive and therapeutic effects for cardiovascular disease, neurodegenerative disorders, cancer, diabetes, osteoporosis, obesity. More recently, scientific interest in the leaf composition and beneficial properties has been growing, documenting that berry leaves can be considered an alternative source of bioactive substances. The main compounds in berry leaves are similar to those in berry fruits, i.e., phenolic acids, flavonols, proanthocyanidins. The leaves are one of the richest sources of chlorogenic acid. The aim of the current research was to investigate the intrapolulation variations of polyphenolic compounds in a bilberry (Vaccinium myrtillus L.) habitat in order to select the most productive plant individuals for introduction in vitro. The total polyphenols, total flavonoid content, total proanthocyanidines and antioxidant capacity were estimated by Folin–Ciocalteu’s method, aluminium nitrate method, n-butanol-HCl assay and DPPH, respectively. The total polyphenol content of bilberry was 52.37 ± 8.62 mg GAE g−1 DW with coefficient of variation (CV%) 16.45%. The radical scavenging activity of the bilberry population defined by DPPH assay was 477.18±111.32 mmol TE g−1 DW with CV – 23.33%. HPLC analyses revealed that the dominant phenolic acid of the bilberry population was chlorogenic acid (17.10 ± 3.21 mg g−1 DW). The results obtained revealed that the analyzed population of bilberry possessed significant intrapopulation variations in respect of the quantity of investigated secondary metabolites.
The aim of this study was profiling of primary metabolites of five Bulgarian Fumaria species (F. ... more The aim of this study was profiling of primary metabolites of five Bulgarian Fumaria species (F. officinalis L., F. thuretii Boiss., F. kralikii Jord., F. rostellata Knaf. and F. schrammii Velen.) by GC-MS analyses. In polar fractions ten carbohydrates, one polyol, ten amino acids and six organic acids were identified. Apolar (lipid) fractions showed the presence of four free fatty acids, two esters of fatty acids with glycerol and two fatty alcohols. Sucrose and fructose were in the highest relative concentrations of identified carbohydrates. Citric acid was the dominant organic acid in polar fractions of five Fumaria species. Predominant compounds in lipid fractions were palmitic acid and 1-stearoyl-glycerol. Principal component analysis (PCA) of GC-MS data of polar and apolar fractions of five Bulgarian Fumaria species differentiates them in two groups (F. officinalis and F. thuretii; F. rostellata and F. schrammii, respectively), while F. kralikii had phythochemical similarity w...
Bulgarian Chemical Communications, 56, SI D2, 96-99, 2024
Dandelion is a well-known edible and medicinal plant with numerous studies of its health benefits... more Dandelion is a well-known edible and medicinal plant with numerous studies of its health benefits. Interest presents its polyphenolic and carbohydrate composition and its non-polar components in the aerial parts and roots have been identified. There are no studies about the composition of the fatty acid phytocomponents in the flowers of the dandelion. The main purpose of the present study is a comparative investigation of n-hexane, ethanol, and n-hexane/ethanol (1:1 v/v) soluble compounds from dandelion flowers (Taraxacum officinale Weber ex F.H. Wigg.) collected during the flowering period. The GC-MS analysis of the non-polar (lipid) fractions showed the presence of 30 biologically active phytocompounds. The fatty acids predominated in the investigated extracts [(50-60 % of total ion current (TIC)], followed by triterpenes (9-11 % of TIC) and phytosterols (7-8 % of TIC). Polyunsaturated fatty acids-linoleic acid and α-linolenic acid (10-15 % of TIC) were identified as the major components. Phytosterols were mainly represented by β-sitosterol (3-4 % of TIC) and stigmasterol (above 2% of TIC), while pentacyclic triterpenes from cycloartenol 3-acetate (3-4% of TIC) and β-amyrin (above 2% of TIC) were found. Based on the fatty acid profile, the nutritional indices directly correlated with the lipid metabolites profile responsible for human health were calculated: Index of atherogenicity (IA)-1.2-1.6; Index of thrombogenicity (IT)-0,6-0,7; Hypocholesterolemic/hypercholesterolemic (HH) ratio-1.0-1.3; Health-promoting index (HPI)-0.6-0.8; Unsaturation index (UI)-72 and linoleic acid/α-linolenic acid (LA/ALA) ratio-1.1. The current results reveal the nutritional potential and health benefits of edible dandelion flowers.
Carlina acanthifolia All. is widely used in traditional medicine due to the presence of essential... more Carlina acanthifolia All. is widely used in traditional medicine due to the presence of essential oil (1-2%) in the outer part of the roots of the plant. It is mainly used for its choleretic and anti-inflammatory properties, as well as for the treatment of gastrointestinal problems. We obtain the fractions by sequential extraction with different solvents (hexane, chloroform, ethyl acetate, and ethanol) from carline thistles (Carlina acanthifolia All.) roots, evaluate the phytochemical compounds and for the first time, we report here the 3D fluorescence excitation-emission spectra. High extractable contents of fatty acids, terpenes, sterols, sugars and polyphenols, flavonoids and carlina oxide were found in the different fractional extracts of Carlina acanthifolia root. Three phenolic acids were detected in the ethyl acetate and n-hexane fraction, benzoic acid, phenylacetic acid, and p-methoxymadelic acid. In addition, fatty acids, pentacyclic triterpenes and sugars have been identified, these phytocomponents are responsible for the fluorescent properties of the roots. The topographic view of the excitation-emission matrix outlines a large strong first maximum (em,1 = 570 nm for exc,1 = 470 nm) connected with the presence of vitamin E and fatty acids and a weaker narrower second one (em,2 = 465 nm for exc,2 = 360 nm), witch is due to the presence of flavonoids, phenolic acids and palmitic acid. The emission spectrum of the main maximum is rather large at the 90% level (em,1 = 60 nm) but is observed over a narrow excitation bandwidth (exm,1 = 25 nm). The Stokes shift Δ is around 100 nm over the excitation range from 430 to 560 nm. Seven elements-Ca, Fe, K, Mg, Mn, Na and Zn, were determined in Carlina acanthifolia All. as potassium has the highest content K = 32.7 ± 0.6 g kg −1 followed by Ca, Mg and Fe (8.24 ± 0.12;1.86 ± 0.03;1.25 ± 0.01 g kg −1) , in mg kg −1 are Na = 212 ± 3 , Mn = 41.9 ± 0.2 and Zn = 26.7 ± 0.3.
The development of functional foods providing health benefits above the basic nutritional needs i... more The development of functional foods providing health benefits above the basic nutritional needs is of growing interest to the food industry. This research aimed to: design fresh prebiotic cheese spreads enriched with agave inulin (AI), thyme (Thymus callieri Borbás ex Velen.) and hawthorn fruit (Crataegus monogyna Jacq.) as plant sources of biologically active compounds; observe the physicochemical and microbiological changes in the cheese during storage at 4°C for 35 days; evaluate the sensory characteristics of the new functional products. Therefore, five experimental groups of fresh cheese spreads were prepareda control; 1% AI + 0.2% thyme; 2% AI + 0.2% thyme; 1% AI + 0.4% hawthorn fruit and 2% AI + 0.4% hawthorn fruit. During the storage, pH in all experimental groups gradually decreased (reaching values between 4.17 and 4.25 on the 35 th day), which corresponded to the increasing titratable acidity (reaching values from 146.30°T to 152.51°T on the 35 th day). The application of thyme and hawthorn fruit did not reduce the total plate count (mesophilic aerobic and facultative anaerobic microorganisms) and yeasts; however, during the storage period the addition of agave inulin stimulated the growth of lactic acid bacteria in the treated samples compared to the control.
The development of functional foods providing health benefits above the basic nutritional needs i... more The development of functional foods providing health benefits above the basic nutritional needs is of great interest to the food industry. This research aimed to: design functional yogurts with agave inulin and extracts from propolis, rose petals and Spirulina platensis; observe the physicochemical and microbiological changes during storage at 4°C for 21 days; evaluate the sensory characteristics of the new functional products. Three kinds of calcium alginate microcapsules (agave inulin + ethanolic propolis extract; agave inulin + ethanolic propolis extract + rose petals extract; agave inulin + ethanolic propolis extract + Spirulina extract) were prepared and applied in yogurts before the coagulation. During the storage, pH in all experimental groups gradually decreased (reaching values between 3.94 and 4.02 on the 21 st day), which corresponded to the increasing titratable acidity (reaching values from 94.17°T to 108.78°T on the 21 st day). The application of microcapsules did not affect the coagulation process and number of lactic acid bacteria in yogurts until the end of storage period. To the best of our knowledge, this is the first study to investigate the application of agave inulin, propolis, rose petals and S. platensis extracts in microencapsulated form in traditional Bulgarian yogurt in order to obtain a dairy product with enhanced functional properties.
The aim of the present study was to evaluate and compare three types of lavender (Lavandula angus... more The aim of the present study was to evaluate and compare three types of lavender (Lavandula angustifolia Mill.) biomasses for their content of biologically active substances and potential application. The first one was from unprocessed lavender (L-UNTR22_Z) and the other two were industrial steam-distilled lavender solid residues (L-SD22_Z and L-SD22_M). Ash, protein, polyuronide content and the degree of esterification of the pectic substances in the biomass were investigated. 70% ethanolic extracts of the residues were prepared and their total polyphenol content and antioxidant activity were evaluated by four methods. Individual phenolic acids, flavonoids, polar non-volatile compounds and polar volatile compounds were also determined by chromatographic analyses. The highest degree of esterification (83.9±0.5%) and protein content (8.15±1.6%) were found in L-SD22_Z extract. L-SD22_M extract demonstrated the highest polyphenolic content and antioxidant activity. Six phenolic acids (protocatehuic, syringic, p-coumaric, ferulic, salicylic, and gallic acid) and five flavonoids ((+)-catechin, (-)-epicatechin, rutin, hesperidin, and quercetin) were detected by HPLC analyses. The detail information about amino acids, sugars, organic and phenolic acids, as well as polar volatile compounds was obtained by GC-MS. The results suggested that the lavender (untreated and residual biomass) are a good source of dietary antioxidants and compounds with potent biological activity.
Functional foods and beverages can be defined as processed products that provide health benefits ... more Functional foods and beverages can be defined as processed products that provide health benefits beyond the basic nutritional needs and reduce the risk of diseases. The design of functional products with improved shelf-life is a new challenge for the food industry. Therefore, this research aimed to: design a functional fruit-herbal beverage; compare the preservation effect of two preservatives (propolis extract and potassium sorbate) added in the beverages; evaluate the sensory characteristics of the newly designed beverages; observe the physico-chemical and microbiological changes during storage at 4℃ for 42 d. The results demonstrated that the addition of propolis extract (0.02%) in the beverage, increased the total polyphenols, total flavonoids and antioxidant activity, compared to the control beverage and the beverage containing potassium sorbate (0.05%). The results from microbiological analyses showed that potassium sorbate and propolis extract effectively inhibited the microbial growth in the treated beverages. However, the propolis extract in a lower concentration (0.02%) was as effective as potassium sorbate in a higher concentration (0.05%) during the entire storage period. Consequently, in addition to being a functional ingredient and a food enhancer, propolis is a prospective natural preservative, which can improve the shelf-life of the food products and beverages.
Propolis is a natural mixture of resins, wax, and pollen from plant buds and flowers, enriched wi... more Propolis is a natural mixture of resins, wax, and pollen from plant buds and flowers, enriched with enzymes and bee saliva. It also contains various essential oils, vitamins, mineral salts, trace elements, hormones, and ferments. It has been found that propolis possesses antimicrobial, antiviral, and anti-inflammatory properties. We have studied the antiviral activity of six extracts of Bulgarian propolis collected from six districts of Bulgaria. The study was conducted against structurally different viruses: human coronavirus strain OC-43 (HCoV OC-43) and human respiratory syncytial virus type 2 (HRSV-2) (enveloped RNA viruses), human herpes simplex virus type 1 (HSV-1) (enveloped DNA virus), human rhinovirus type 14 (HRV-14) (non-enveloped RNA virus) and human adenovirus type 5 (HadV-5) (non-enveloped DNA virus). The influence of the extracts on the internal replicative cycle of viruses was determined using the cytopathic effect (CPE) inhibition test. The virucidal activity, its impact on the stage of viral adsorption to the host cell, and its protective effect on healthy cells were evaluated using the final dilution method, making them the focal points of interest. The change in viral infectivity under the action of propolis extracts was compared with untreated controls, and Δlgs were determined. Most propolis samples administered during the viral replicative cycle demonstrated the strongest activity against HCoV OC-43 replication. The influence of propolis extracts on the viability of extracellular virions was expressed to a different degree in the various viruses studied, and the effect was significantly stronger in those with an envelope. Almost all extracts significantly inhibited the adsorption step of the herpes virus and, to a less extent, of the coronavirus to the host cell, and some of them applied before viral infection demonstrated a protective effect on healthy cells. Our results enlarge the knowledge about the action of propolis and could open new perspectives for its application in viral infection treatment.
Propolis (bee glue), a valuable biological mixture produced by European honey bees (Apis mellifer... more Propolis (bee glue), a valuable biological mixture produced by European honey bees (Apis mellifera L.), is widely used as a remedy in traditional and alternative medicine, as an effective food biopreservative and as a nutritional value enhancer. The present study aimed to investigate eighty propolis samples collected from all twenty-eight districts of Bulgaria in the period of 2020-2022 in order to determine their physicochemical properties as well as their antioxidant and antimicrobial potential. The raw propolis samples exhibited brown or green colour depending on the climatic zone from which they are collected and pH values from 4.82 to 5.87, while the moisture content ranged between 0.98% and 2.97%. The total phenolics content (TPC) and total flavonoids content (TFC) varied from 63.14 mg GAE/g to 737.27 mg GAE/g, and from 29.22 mg QE/g to 234.17 mg QE/g, respectively. The propolis samples demonstrated significant antioxidant potential determined by DPPH and FRAP methods, from 18.56 mM TE/g to 1598.66 mM TE/g and from 82.28 mM TE/g to 1208.81 mM TE/g, respectively, whose values showed a positive correlation (r 2) with the TPC and TFC. The results from the antimicrobial screening revealed that the methanolic propolis extracts in concentration of 20 mg/ml exhibited the highest inhibitory effect on the Gram-positive bacteria such as Micrococcus luteus 2YC-YT, Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 25923, Listeria monocytogenes NBIMCC 8632 and Listeria innocua ATCC 33090.
Tropical Journal of Natural Product Research, 2023
It is known that plants from the Carlina genus possessed many biological activity due to the bioa... more It is known that plants from the Carlina genus possessed many biological activity due to the bioactive compounds. The current study investigates the phytochemical constituents and antioxidant potential of the different vegetal parts of Carlina vulgaris L., Carlina acanthifolia All. and Carlina corymbosa L. The samples (roots and aerial part) were collected from Bulgaria (Golo Bardo and Vlahina mountains). Total phenols, flavonoids, individual phenolic compounds, triterpenes, phytosterols, carlina oxide, fructans, and individual sugars were determined. Antioxidant potential was evaluated using four methods. The highest total phenolic content was found in ethanol extract from C. acantifololia All. roots. Three phenolic acids (chlorogenic acid, ferulic acid, and salicylic acid), three flavonoids (rutin, hesperidin, and quercetin), and triterpenes (lupeol and betulin) were detected in all samples (mainly in roots). However, p-coumaric acid and ursolic acid were detected only in C. vulgaris, while carlina oxide was found only in C. acantifololia All. roots. The result showed that the roots of C. acanthifolia All. were characterized by appreciable amounts of total fructans (20 g/100 g dry weight), while inulin represented 18-12 g/100 g of dry weight. Sugars were found in all plant materials. The current study provides data about the chemical composition of extracts obtained from three members of the Carlina genus and their use as a source of antioxidants, phenolic compounds, carlina oxide, and inulin-type prebiotics.
Trop J Nat Prod Res, July 2022; 6(7):1113-1118, 2022
Mentioned for the first time in the Materia medica by Pedanios Dioscorides, Sideritis scardica ha... more Mentioned for the first time in the Materia medica by Pedanios Dioscorides, Sideritis scardica has been well known for its prolific anti-inflammatory properties for centuries. The name derives from the Greek word "sideros", meaning iron. Ancient soldiers used the plant to help the healing process of cut wounds caused by iron weapons. The European Medical Agency Committee on Herbal Medicinal Products points to its traditional use for the relief of cough, associated with cold and gastrointestinal disorders. 1 Other described biological activities of the herb include anti-glioma, cytotoxic, antimicrobial, and antirheumatic. 2-5 Belonging to the Lamiaceae Family, Sideritis scardica has become more popular outside the Balkan Peninsula in the last decades. Different studies have confirmed its positive effect on cognitive and neurodegenerative diseases. 6-8 The phytochemical profile of the plant reveals many polyphenolic compoundsphenylethanoid glycosides, acetylated and nonacetylated flavonoids, and several organic phenolic acids. 2,3,9,10 With this composition, preparations from Sideritis scardica and other herbs belonging to the same genus in the Mediterranean display prominent antioxidant activity. Oxidative stress has long been linked with neurodegenerative processes, whether as a cause or part of a pathological cascade induced by other factors.
Burdock (Arctium lappa L.) roots were used as a medicinal plant or vegetable worldwide. The resea... more Burdock (Arctium lappa L.) roots were used as a medicinal plant or vegetable worldwide. The research aimed to obtain different fractions by sequential extraction (hexane, chloroform, ethyl acetate water) of burdock roots and to evaluate phytochemical compounds in them. Antioxidant and antimicrobial properties of nonpolar fractions were evaluated. Ethyl acetate fraction contained the highest total phenolics, total flavonoids, and derivatives of caffeic acids. Phenolic acids (mainly chlorogenic, caffeic acid, and p-coumaric acids) were detected only in the ethyl acetate fraction, while in the hexane fraction was found only triterpenes. Due to the high polyphenol content, the ethyl acetate fraction demonstrated the highest antioxidant activity. Three fractions revealed antimicrobial activity against Salmonella sp., Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Proteus vulgaris, Staphylococcus aureus, Bacillus cereus, and Candida albicans. The lowest minimum inhibitory concentration (>1 mg/ml) showed an ethyl acetate fraction against Pseudomonas aeruginosa and Bacillus cereus. From the water fraction was isolated inulin-type fructan with a degree of polymerization 20-24 with promising functional properties. This study showed the potential application of burdock root fractions as a rich source of phytochemicals with antimicrobial, antioxidant activities, and potential prebiotic effect due to the 7 g/100 g inulin content in them.
The task of this study was to perform the "green" synthesis of lactose octaacetate through microw... more The task of this study was to perform the "green" synthesis of lactose octaacetate through microwave irradiation and to establish their biological activities. Lactose ester was prepared after microwave-assisted esterification of lactose with acetic anhydride (yield 85-90 %). Lactose octaacetate was characterized by a high degree of acetylation (DS 3.2-3.7). The lactose esters' structure was elucidated by infrared spectroscopy and nuclear magnetic resonance spectroscopy. Lactose octaacetate showed better antifungal activities than antibacterial activities. It possessed slight to moderate antifungal activities against Aspergillus niger ATCC 1015, Penicillium sp., Rhizopus sp., Fusarium moniliforme ATCC 38932. Lactose acetates demonstrated low cytotoxicity against three cell lines: Madin-Darby bovine kidney (MDBK) cells, human epithelial type 2 (HEp-2), and Madin-Darby canine kidney (MDCK) cells. This is the first report for antiviral activity of lactose acetates against herpes simplex virus type 1 (HSV-1), influenza virus A/Panama/2007/99/H3N2-(IAV/H3N2), PV-1 and Coxsackievirus B1. It was found that this compound showed activity with SI = 2.4 only against PV-1, but against HSV-1, IAV/H3N2, and Coxsackievirus B1 was inactive. The current study demonstrated the applications of lactose acetates as antimicrobial and antiviral substances in food, pharmaceutical, agricultural and cosmetic preparations.
In the present work, ice cream mixtures with 5%, 10% and 15% lingonberry extract were studied. Th... more In the present work, ice cream mixtures with 5%, 10% and 15% lingonberry extract were studied. The lingonberry (Vaccinium vitis-idaea L.) is a source of anthocyanins and flavonoids, which are the bioactive components with good antioxidant properties. There was a significant increase in antioxidant activity (p<0.05) from 133.3 ± 5.6 mM TE/100 g to 249.8 ± 8.3 mM TE/100 g (ABTS method) with increasing the concentration of the extract from 5% to 15%, respectively. Significant changes (p<0.05) in the acidity and dry matter of the samples with lingonberry extract were recorded. After 30 days of storage, a decrease in the antioxidant properties (p<0.05) of the ice cream samples was observed but higher values (mM TE/100 g) were maintained compared to the sample without extract. The color characteristics of the samples were also influenced by the concentration of the extract used. During storage, the highest stability of the colorimetric index a* (red component) was established, which indicates relative color stability during storage.
Current Research in Nutrition and Food Science, 2022
Propolis is a complex honey bee product known for its antioxidant potential and antimicrobial act... more Propolis is a complex honey bee product known for its antioxidant potential and antimicrobial activity, widely used as a food biopreservative and food additive. The object of the current research was to investigate the effects of carboxymethyl cellulose (CMC) edible coatings applied alone and in combination with a propolis extract on the quality parameters and storage life of fresh blueberries during refrigerated storage for 20 days. For this purpose, three experimental groups were prepared: blueberries without coating (control group), blueberries with 1%CMC coatings and blueberries with 1% CMC coatings+1% propolis extract (CMC+P). During the storage, the physicochemical and microbiological parameters of the experimental groups were evaluated. The use of CMC and CMC+P coatings reduced the weight loss by 1.13% and 1.67% in comparison with the control group on the 20-th day of storage. A significant decrease in decay percentage was found, which was in the great extent in the CMC+P coated fruit compared to the CMC coatings and the control fruit. The CMC and CMC+P edible coatings did not affect the TSS levels, the decreasing TA and increasing pH values. The application of CMC and CMC+P coatings did not cause a protective effect on the lowering values of total phenolic and anthocyanin contents in both treatments, but exhibited a positive influence on the antioxidant activity in CONTACT Yulian Dimitrov Tumbarski
Доклади на Българската академия на науките Comptes rendus de l’Acad´emie bulgare des Sciences, 74, No 12, 2021
Bilberries (Vaccinium myrtillus L.) belong to the Ericaceae family and have been traditionally us... more Bilberries (Vaccinium myrtillus L.) belong to the Ericaceae family and have been traditionally used in folk medicine for centuries because of their high content of polyphenolic compounds. Berry polyphenols exhibit strong antioxidant properties that could have preventive and therapeutic effects for cardiovascular disease, neurodegenerative disorders, cancer, diabetes, osteoporosis, obesity. More recently, scientific interest in the leaf composition and beneficial properties has been growing, documenting that berry leaves can be considered an alternative source of bioactive substances. The main compounds in berry leaves are similar to those in berry fruits, i.e., phenolic acids, flavonols, proanthocyanidins. The leaves are one of the richest sources of chlorogenic acid. The aim of the current research was to investigate the intrapolulation variations of polyphenolic compounds in a bilberry (Vaccinium myrtillus L.) habitat in order to select the most productive plant individuals for introduction in vitro. The total polyphenols, total flavonoid content, total proanthocyanidines and antioxidant capacity were estimated by Folin–Ciocalteu’s method, aluminium nitrate method, n-butanol-HCl assay and DPPH, respectively. The total polyphenol content of bilberry was 52.37 ± 8.62 mg GAE g−1 DW with coefficient of variation (CV%) 16.45%. The radical scavenging activity of the bilberry population defined by DPPH assay was 477.18±111.32 mmol TE g−1 DW with CV – 23.33%. HPLC analyses revealed that the dominant phenolic acid of the bilberry population was chlorogenic acid (17.10 ± 3.21 mg g−1 DW). The results obtained revealed that the analyzed population of bilberry possessed significant intrapopulation variations in respect of the quantity of investigated secondary metabolites.
The aim of this study was profiling of primary metabolites of five Bulgarian Fumaria species (F. ... more The aim of this study was profiling of primary metabolites of five Bulgarian Fumaria species (F. officinalis L., F. thuretii Boiss., F. kralikii Jord., F. rostellata Knaf. and F. schrammii Velen.) by GC-MS analyses. In polar fractions ten carbohydrates, one polyol, ten amino acids and six organic acids were identified. Apolar (lipid) fractions showed the presence of four free fatty acids, two esters of fatty acids with glycerol and two fatty alcohols. Sucrose and fructose were in the highest relative concentrations of identified carbohydrates. Citric acid was the dominant organic acid in polar fractions of five Fumaria species. Predominant compounds in lipid fractions were palmitic acid and 1-stearoyl-glycerol. Principal component analysis (PCA) of GC-MS data of polar and apolar fractions of five Bulgarian Fumaria species differentiates them in two groups (F. officinalis and F. thuretii; F. rostellata and F. schrammii, respectively), while F. kralikii had phythochemical similarity w...
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found in ethanol extract from C. acantifololia All. roots. Three phenolic acids (chlorogenic acid, ferulic acid, and salicylic acid), three flavonoids (rutin, hesperidin, and quercetin), and triterpenes (lupeol and betulin) were detected in all samples (mainly in roots). However, p-coumaric acid
and ursolic acid were detected only in C. vulgaris, while carlina oxide was found only in C. acantifololia All. roots. The result showed that the roots of C. acanthifolia All. were characterized by appreciable amounts of total fructans (20 g/100 g dry weight), while inulin represented 18-12 g/100 g of dry weight. Sugars were found in all plant materials. The current study provides data about the chemical composition of extracts obtained from three members of the Carlina genus and their use as a source of antioxidants, phenolic compounds, carlina oxide, and inulin-type prebiotics.
The total polyphenol content of bilberry was 52.37 ± 8.62 mg GAE g−1 DW with coefficient of variation (CV%) 16.45%. The radical scavenging activity of the bilberry population defined by DPPH assay was 477.18±111.32 mmol TE g−1 DW with CV – 23.33%. HPLC analyses revealed that the dominant phenolic acid of the bilberry population was chlorogenic acid (17.10 ± 3.21 mg g−1 DW). The results obtained revealed that the analyzed population of bilberry possessed significant intrapopulation variations in respect of the quantity of investigated secondary metabolites.
found in ethanol extract from C. acantifololia All. roots. Three phenolic acids (chlorogenic acid, ferulic acid, and salicylic acid), three flavonoids (rutin, hesperidin, and quercetin), and triterpenes (lupeol and betulin) were detected in all samples (mainly in roots). However, p-coumaric acid
and ursolic acid were detected only in C. vulgaris, while carlina oxide was found only in C. acantifololia All. roots. The result showed that the roots of C. acanthifolia All. were characterized by appreciable amounts of total fructans (20 g/100 g dry weight), while inulin represented 18-12 g/100 g of dry weight. Sugars were found in all plant materials. The current study provides data about the chemical composition of extracts obtained from three members of the Carlina genus and their use as a source of antioxidants, phenolic compounds, carlina oxide, and inulin-type prebiotics.
The total polyphenol content of bilberry was 52.37 ± 8.62 mg GAE g−1 DW with coefficient of variation (CV%) 16.45%. The radical scavenging activity of the bilberry population defined by DPPH assay was 477.18±111.32 mmol TE g−1 DW with CV – 23.33%. HPLC analyses revealed that the dominant phenolic acid of the bilberry population was chlorogenic acid (17.10 ± 3.21 mg g−1 DW). The results obtained revealed that the analyzed population of bilberry possessed significant intrapopulation variations in respect of the quantity of investigated secondary metabolites.