Staphylococcus aureus and Pseudomonas aeruginosa are bacteria that cause biofilm-associated infections. The aim of this study was to determine the activity of combined betacyanin fractions from Amaranthus dubius (red spinach) and... more
Staphylococcus aureus and Pseudomonas aeruginosa are bacteria that cause biofilm-associated infections. The aim of this study was to determine the activity of combined betacyanin fractions from Amaranthus dubius (red spinach) and Hylocereus polyrhizus (red pitahaya) against biofilms formed by co-culture of S. aureus and P. aeruginosa on different polymer surfaces. Various formulations containing different concentrations of the betacyanin fractions were investigated for biofilm-inhibiting activity on polystyrene surfaces using crystal violet assay and scanning electron microscopy. A combination of each betacyanin fraction (0.625 mg mL−1) reduced biofilm formation of five S. aureus strains and four P. aeruginosa strains from optical density values of 1.24–3.84 and 1.25–3.52 to 0.81–2.63 and 0.80–1.71, respectively. These combined fractions also significantly inhibited dual-species biofilms by 2.30 and reduced 1.0–1.3 log CFU cm−2 bacterial attachment on polymer surfaces such as polyvinyl chloride, polyethylene, polypropylene and silicone rubber. This study demonstrated an increase in biofilm-inhibiting activity against biofilms formed by two species using combined fractions than that by using single fractions. Betacyanins found in different plants could collectively be used to potentially decrease the risk of biofilm-associated infections caused by these bacteria on hydrophobic polymers.
Betalains are plant derived natural pigments that are presently gaining popularity for use as natural colorants in the food industry. The growing interest of consumers in the aesthetic, nutritional and safety aspects of food has increased... more
Betalains are plant derived natural pigments that are presently gaining popularity for use as natural colorants in the food industry. The growing interest of consumers in the aesthetic, nutritional and safety aspects of food has increased the demand for natural pigments such as betalains to be used as alternative colorants in food products. Although betalains from red beetroot are one of the most widely used food colorant, betalains are not as well studied as compared to other natural pigments such as anthocyanins, carotenoids or chlorophylls. This paper reviews the pharmacological properties, such as antioxidant, anti-cancer, anti-lipidemic and antimicrobial activity of betalains derived from sources such as red beetroot, amaranth, prickly pear and red pitahaya, for potential application as functional foods.
The aim of this study was to identify pigments present in the red dragon fruit (Hylocereus polyrhizus) and to further investigate the antioxidant properties in this fruit. Pigment was identified using the High Performance Liquid... more
The aim of this study was to identify pigments present in the red dragon fruit (Hylocereus polyrhizus) and to further investigate the antioxidant properties in this fruit. Pigment was identified using the High Performance Liquid Chromatography (HPLC) and results confirmed the presence of betanin in sample at a retention time of 11.5 min which corresponded to the retention time of the betanin standard used. In the antioxidant properties determination, there were 86.10 mg of total polyphenolic compound in 0.50 g of dried dragon fruit extract using the total polyphenol assay which expresses gallic acid as equivalent. The reducing power assay further confirmed the antioxidant activity present in dragon fruit where the reducing capability increased from 0.18 to 2.37 with the increase of dry weight sample from 0.03 to 0.5 g. The Vanillin-HCl assay which measures the amount of condensed tannin showed that the dried dragon fruit sample had an equivalent of 2.30 mg catechin/g. The DPPH center dot radical scavenging activity determination showed that the effective concentration (EC(50)) for dragon fruit was 2.90 mM vitamin C equivalents/g dried extract.
Betacyanins are reddish to violet pigments that can be found in red pitahaya (Hylocereus polyrhizus) and red spinach (Amaranthus dubius). This study investigated the impact of sub-fractionation (solvent partitioning) on betacyanin content... more
Betacyanins are reddish to violet pigments that can be found in red pitahaya (Hylocereus polyrhizus) and red spinach (Amaranthus dubius). This study investigated the impact of sub-fractionation (solvent partitioning) on betacyanin content in both plants. Characterization of betacyanins and evaluation of their antimicrobial activities were also carried out. Betanin was found in both plants. In addition, isobetanin, phyllocactin and hylocerenin were found in red pitahaya whereas amaranthine and decarboxy-amaranthine were found in red spinach. Sub-fractionated red pitahaya and red spinach had 23.5 and 121.5 % more betacyanin content, respectively, than those without sub-fractionation. Sub-fractionation increased the betanin and decarboxy-amaranthine content in red pitahaya and red spinach, respectively. The betacyanin fraction from red spinach (minimum inhibitory concentration [MIC] values: 0.78–3.13 mg/mL) demonstrated a better anti-microbial activity profile than that of red pitahaya (MIC values: 3.13–6.25 mg/mL) against nine Gram-positive bacterial strains. Similarly, the red spinach fraction (MIC values: 1.56–3.13 mg/mL) was more active than the red pitahaya fraction (MIC values: 3.13–6.25 mg/mL) against five Gram-negative bacterial strains. This could be because of a higher amount of betacyanin, particularly amaranthine in the red spinach.
Red pitahaya fruit is rich in purplish-red color water-soluble betacyanins. The effect of refrigerated storage at 4 °C on the betacyanin composition of red pitahaya was monitored each day, for one week, using HPLC. The betacyanin content... more
Red pitahaya fruit is rich in purplish-red color water-soluble betacyanins. The effect of refrigerated storage at 4 °C on the betacyanin composition of red pitahaya was monitored each day, for one week, using HPLC. The betacyanin content of red pitahaya had increased by 57.2% after storage for six days at 4 °C. From day 2 to day 7, the phyllocactin content decreased from 45.4 ± 1.5% to 38.3 ± 3.1%, whereas the betanin content increased from 37.9 ± 1.6% to 42.7 ± 1.5%. Antimicrobial activity was determined using the broth microdilution assay and expressed as minimum inhibitory concentration (MIC). As compared to the freshly harvested fruits (MIC values: 50,000– > 50,000 μg mL −1), fruits that were stored for six days at 4 °C demonstrated better anti-microbial activity (MIC values: 3130–6250 μg mL −1) against 10 pathogenic Gram-positive and 6 Gram-negative bacteria. Betacyanin rich extract was also examined against normal human cell lines (HEK-293 and THP-1) and found to be not cytotoxic at the levels of 0.39–3.13 mg mL −1. In summary, refrigerated storage for 6 days increased the betacyanin content, changed the betacyanin composition in red pitahaya and contributed to higher antimicrobial activity.
The present study investigated the effects of pH (pH 3, 4, 5 and 6) treatment and refrigerated storage at 4 C on the stability of colourant preparations from red pitahaya and compared to a commercial col-ourant preparations from red beet,... more
The present study investigated the effects of pH (pH 3, 4, 5 and 6) treatment and refrigerated storage at 4 C on the stability of colourant preparations from red pitahaya and compared to a commercial col-ourant preparations from red beet, E-162. The potential of using colourant preparations from red pit-ahaya in yoghurt and compared to E-162 was also investigated. Immediately after pH treatment, the highest percentage of reduction of betacyanin was observed at pH 3. The loss of betacyanin content in yoghurts containing colourant preparations from red pitahaya and E-162 over 14-days of refrigerated storage was 1.0± 0% and 1.6± 0.1%, respectively. Syneresis in yoghurt containing colourant preparations from red pitahaya and E-162 were lower than that of plain yoghurt. The addition of betacyanins from red pitahaya or E-162 increased the free radical scavenging activity in yoghurts. The total microbial counts of Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus in yoghurts containing colourant preparations from red pitahaya and E-162 were in the 10 8 e10 9 CFU/mL range. The colour acceptability of yoghurt containing colourant preparation from red pitahaya was similar with E-162 and a commercial strawberry flavoured yoghurt suggesting its potential application as a natural functional colourant.
The antioxidant properties of fruits (peels and pulps) and pulps of two species of Hylocereus, Hylocereus polyrhizus (red dragon fruit) and Hylocereus undatus (white dragon fruit) were investigated. The ascorbic acid and total phenolic... more
The antioxidant properties of fruits (peels and pulps) and pulps of two species of Hylocereus, Hylocereus polyrhizus (red dragon fruit) and Hylocereus undatus (white dragon fruit) were investigated. The ascorbic acid and total phenolic contents of pulps were higher than those of fruits (peels and pulps) of the two species of Hylocereus. The anti-radical power measured using 2,2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activity ranked in the following order: pulp of H. undatus ≈ pulp of H. polyrhizus > fruit (peel and pulp) of H. polyrhizus > fruit (peel and pulp) of H. undatus. The ferrous ion chelating activity ranked in the following order: pulp of H. undatus > fruit (peel and pulp) of H. polyrhizus > fruit (peel and pulp) of H. undatus > pulp of H. polyrhizus. Both phenolics and ascorbic acids contributed to the anti-radical power of the two species of Hylocereus fruits but the latter contributed more. By taking into account the free radical scavenging ...
Aims: To investigate the biofilm inhibitory activity of betacyanins from red pitahaya (Hylocereus polyrhizus) and red spinach (Amaranthus dubius) against Staphylococcus aureus and Pseudomonas aeruginosa biofilms. Methods and Results: The... more
Aims: To investigate the biofilm inhibitory activity of betacyanins from red pitahaya (Hylocereus polyrhizus) and red spinach (Amaranthus dubius) against Staphylococcus aureus and Pseudomonas aeruginosa biofilms. Methods and Results: The pulp of red pitahaya and the leaves of red spinach were extracted using methanol followed by subfractionation to obtain betacyanin fraction. The anti-biofilm activity was examined using broth microdilution assay on polystyrene surfaces and expressed as minimum biofilm inhibitory concentration (MBIC). The betacyanin fraction from red spinach showed better anti-biofilm activity (MBIC: 0.313–1.25 mg ml-1) against five Staph. aureus strains while the betacyanin fraction from red pitahaya showed better anti-biofilm activity (MBIC: 0.313–0.625 mg ml-1) against four P. aeruginosa strains. Both betacyanin fraction significantly reduced hydrophobicity of Staph. aureus and P. aeruginosa strains. Numbers of Staph. aureus and P. aeruginosa attached to polystyrene were also reduced without affecting their cell viability. Conclusion: Betacyanins can act as anti-biofilm agents against the initial step of biofilm formation, particularly on a hydrophobic surface like polystyrene. Significance and Impact of the Study: This study is the first to investigate the use of betacyanin as a biofilm inhibitory agent. Betacyanin could potentially be used to reduce the risk of biofilm-associated infections.
This study investigated the antiviral activity of betacyanins from red pitahaya (Hylocereus polyrhizus) and red spinach (Amaran-thus dubius) against dengue virus type 2 (DENV-2). The pulp of red pitahaya and the leaves of red spinach were... more
This study investigated the antiviral activity of betacyanins from red pitahaya (Hylocereus polyrhizus) and red spinach (Amaran-thus dubius) against dengue virus type 2 (DENV-2). The pulp of red pitahaya and the leaves of red spinach were extracted using methanol followed by sub-fractionation and Amberlite XAD16N column chromatography to obtain betacyanin fractions. The half maximum cytotoxicity concentration for betacyanin fractions from red pitahaya and red spinach on Vero cells were 4.346 and 2.287 mg ml −1 , respectively. The half-maximal inhibitory concentration (IC 50) of betacyanin fraction from red pitahaya was 125.8 μg ml −1 with selectivity index (SI) of 5.8. For betacyanin fraction from red spinach, the IC 50 value was 14.62 μg ml −1 with SI of 28.51. Using the maximum non-toxic betacyanin concentration, direct virucidal effect against DENV-2 was obtained from betacyanin fraction from red pitahaya (IC 50 of 126.70 μg ml −1 ; 95.0 % virus inhibition) and red spinach (IC 50 value of 106.80 μg ml −1 ; 65.9 % of virus inhibition). Betacyanin fractions from red pitahaya and red spinach inhibited DENV-2 in vitro.
The effect of solvent, substrate-to-solvent ratio and concentration of pectinase on the extraction of beta-cyanins from the pulp of red pitahaya (Hylocereus poly-rhizus) was evaluated with respect to yield, betacyanin content (BC) and... more
The effect of solvent, substrate-to-solvent ratio and concentration of pectinase on the extraction of beta-cyanins from the pulp of red pitahaya (Hylocereus poly-rhizus) was evaluated with respect to yield, betacyanin content (BC) and total sugar content. The application of betacyanins from red pitahaya in ice cream was then evaluated by comparison to a commercial colourant, E-162. Without the use of pectinase, the highest yields (9.11 ± 0.35%) of betacyanins were obtained using 95% ethanol at a substrate-to-solvent ratio of 1:1. With the use of pectinase at a concentration of 1.5%, the highest yield (17.11-17.45%) of betacyanins were obtained using water as a solvent at a substrate-to-solvent ratio of 1:1 and 1:2. Pectinase treatment (1.5-2.5%) using water as a solvent yielded betacyanins with the highest BC (126.47-130.83 g kg-1) and lowest total sugar content (57.85-59.74 g kg-1). The BC and total colour changes were similar in ice cream containing betacyanins from red pitahaya and E-162 throughout the 21-days of frozen storage at-18°C. Betacyanins from red pitahaya or E-162 enhanced the antioxidant properties of ice cream. The sensory evaluation of ice cream containing betacyanins from red pitahaya showed a better colour acceptability than E-162.
Staphylococcus aureus and Pseudomonas aeruginosa are bacteria that cause biofilm-associated infections. The aim of this study was to determine the activity of combined betacyanin fractions from Amaranthus dubius (red spinach) and... more
Staphylococcus aureus and Pseudomonas aeruginosa are bacteria that cause biofilm-associated infections. The aim of this study was to determine the activity of combined betacyanin fractions from Amaranthus dubius (red spinach) and Hylocereus polyrhizus (red pitahaya) against biofilms formed by co-culture of S. aureus and P. aeruginosa on different polymer surfaces. Various formulations containing different concentrations of the betacyanin fractions were investigated for biofilm-inhibiting activity on polystyrene surfaces using crystal violet assay and scanning electron microscopy. A combination of each betacyanin fraction (0.625 mg mL−1) reduced biofilm formation of five S. aureus strains and four P. aeruginosa strains from optical density values of 1.24–3.84 and 1.25–3.52 to 0.81–2.63 and 0.80–1.71, respectively. These combined fractions also significantly inhibited dual-species biofilms by 2.30 and reduced 1.0–1.3 log CFU cm−2 bacterial attachment on polymer surfaces such as polyvi...
A study was conducted to concentrate the betacyanin in red pitahaya extracts by removing the coexisting sugars by fermentation. Four lactic acid bacteria (Lactobacillus acidophilus, L. casei, L. rhamnosus and L. plantarum) and a yeast... more
A study was conducted to concentrate the betacyanin in red pitahaya extracts by removing the coexisting sugars by fermentation. Four lactic acid bacteria (Lactobacillus acidophilus, L. casei, L. rhamnosus and L. plantarum) and a yeast species (Saccharomyces cerevisiae) were screened to determine their efficiency to reduce sugar content in red pitahaya extracts for concentration of their betacyanin content. A reduction of sugar content (19.8–56.4%) and increase in the yield of betacyanins were observed in all extracts as compared to the control, which was not innoculated with any microorganisms after 1 day of fermentation. The lowest total sugar content (26.40 g/L) was observed in extracts fermented by S. cerevisiae. Extracts fermented by S. cerevisiae also showed greater numbers of microbial cells (10.75 log CFU/mL) and a lower pH value (3.54) compared to those (6.89–8.48 log CFU/mL and pH 4.64–5.42) of the Lactobacillus spp. after 1 day of fermentation. An optimization step using response surface methodology (RSM) was then conducted using S. cerevisiae. Temperature, time and agitation speed were found to have a significant effect on the total sugar content and BC of concentrated betacyanins from red pitahaya, while the yield of betacyanins was significantly influenced by temperature and agitation speed.
The effects of temperature (30, 50, 85 and 100 °C) treatment and 10 weeks of refrigerated storage (4 °C) on the betacyanin content and colour stability of betacyanins from red pitahaya (Hylocereus polyrhizus) were investigated and... more
The effects of temperature (30, 50, 85 and 100 °C) treatment and 10 weeks of refrigerated storage (4 °C) on the betacyanin content and colour stability of betacyanins from red pitahaya (Hylocereus polyrhizus) were investigated and compared to red beet (Beta vulgaris; E-162) which was used as a control. Temperature treatment at 50 and 85 °C caused a greater reduction in betacyanin content (BC) in E-162 compared to red pitahaya by inducing changes in betacyanin profile. The 10 weeks of refrigerated storage at 4 °C induced colour changes in betacyanins from red pitahaya and E-162. In milk, betacyanins from red pita-haya presented a lower loss of BC and total colour changes (DE*) compared to E-162. The microbial onset in milk containing betacyanins from red pitahaya and E-162 was delayed up to day 5 of refrigerated storage at 4 °C compared to day 3 in plain milk. Milk containing betacyanins from red pitahaya showed better colour acceptability (3.89 AE 1.89) compared to E-162 (6.10 AE 1.71). Hence, betacyanins from red pitahaya may be a potential natural functional colourant to simulate strawberry colour in milk.
Aims: Betanin is a red plant pigment belonging to the group called betalain. This present study aimed at investigating the effect betanin from beetroot (Beta vulgaris subsp. vulgaris) as a potential anti-infective agent against... more
Aims: Betanin is a red plant pigment belonging to the group called betalain. This present study aimed at investigating the effect betanin from beetroot (Beta vulgaris subsp. vulgaris) as a potential anti-infective agent against methicillin-resistant Staphylococcus aureus (MRSA) using a Caenorhabditis elegans infection model. Methodology and results: The minimum inhibitory concentration of betanin against MRSA strain ATCC 33591 was determined to establish the non-inhibitory concentration. The minimum inhibitory concentration of betanin against MRSA was > 20 mg/mL. C. elegans were then infected with MRSA and treated with betanin at different concentrations (100, 200, 300 and 400 µg/mL). Betanin at 200 µg/mL significantly improved worm survival following infection whereby the mean time to death was extended about 76 h upon treatment. Intestinal colonization by MRSA of worms exposed to betanin extract was similar to non-betanin-treated infected worms. Conclusion, significance and impact of study: The enhanced survival of MRSA-infected worms upon betanin treatment was not a result of the activation of the host antimicrobial mechanism. Betanin from beetroot can be potentially used as a natural anti-infective agent as a mean to reduce antimicrobial resistance of S. aureus or used in combination with established antimicrobials to increase their effectiveness.
This study investigated the antiviral activity of betacyanins from red pitahaya (Hylocereus polyrhizus) and red spinach (Amaran-thus dubius) against dengue virus type 2 (DENV-2). The pulp of red pitahaya and the leaves of red spinach were... more
This study investigated the antiviral activity of betacyanins from red pitahaya (Hylocereus polyrhizus) and red spinach (Amaran-thus dubius) against dengue virus type 2 (DENV-2). The pulp of red pitahaya and the leaves of red spinach were extracted using methanol followed by sub-fractionation and Amberlite XAD16N column chromatography to obtain betacyanin fractions. The half maximum cytotoxicity concentration for betacyanin fractions from red pitahaya and red spinach on Vero cells were 4.346 and 2.287 mg ml −1 , respectively. The half-maximal inhibitory concentration (IC 50) of betacyanin fraction from red pitahaya was 125.8 μg ml −1 with selectivity index (SI) of 5.8. For betacyanin fraction from red spinach, the IC 50 value was 14.62 μg ml −1 with SI of 28.51. Using the maximum non-toxic betacyanin concentration, direct virucidal effect against DENV-2 was obtained from betacyanin fraction from red pitahaya (IC 50 of 126.70 μg ml −1 ; 95.0 % virus inhibition) and red spinach (IC 50 value of 106.80 μg ml −1 ; 65.9 % of virus inhibition). Betacyanin fractions from red pitahaya and red spinach inhibited DENV-2 in vitro.