Arbutin, a hydroquinone glucoside, has been detected in ca. 50 plant families, especially in the ... more Arbutin, a hydroquinone glucoside, has been detected in ca. 50 plant families, especially in the plants of the Asteraceae, Ericaceae, Proteaceae and Rosaceae families. It is one of the most widely used natural skin-whitening agents. In addition to its skin whitening property, arbutin possesses other therapeutically relevant biological properties, e.g., antioxidant, antimicrobial and anti-inflammatory, as well as anticancer potential. This review presents, for the first time, a comprehensive overview of the distribution of arbutin in the plant kingdom and critically appraises its therapeutic potential as an anticancer agent based on the literature published until the end of August 2022, accessed via several databases, e.g., Web of Science, Science Direct, Dictionary of Natural Products, PubMed and Google Scholar. The keywords used in the search were arbutin, cancer, anticancer, distribution and hydroquinone. Published outputs suggest that arbutin has potential anticancer properties a...
Advances in Pharmacological and Pharmaceutical Sciences
Plants act as a rich source of novel natural pesticides. In the backdrop of the recent revival of... more Plants act as a rich source of novel natural pesticides. In the backdrop of the recent revival of interest in developing plant-based insecticides, this study was carried out to investigate the pesticidal activity of Sundarban mangrove plants. A total of nine different plant parts from five plants, namely, Aegiceras corniculatum, Excoecaria agallocha, Heritiera fomes, Xylocarpus moluccensis, and Xylocarpus granatum, were extracted with methanol and tested for insecticidal activity against two common stored product pests Sitophilus oryzae and Sitophilus zeamais using direct contact feeding deterrent wafer disc method. Three bark extracts from A. corniculatum, E. agallocha, and H. fomes showed potent and statistically significant insecticidal activity against both S. oryzae and S. zeamais pests (80–100% mortality). All the active bark extracts were further fractionated using C-18 solid-phase extraction (SPE) columns and tested for their insecticidal activity against S. oryzae pest to i...
Ruta L. is a typical genus of the citrus family, Rutaceae Juss. and comprises ca. 40 different sp... more Ruta L. is a typical genus of the citrus family, Rutaceae Juss. and comprises ca. 40 different species, mainly distributed in the Mediterranean region. Ruta species have long been used in traditional medicines as an abortifacient and emmenagogue and for the treatment of lung diseases and microbial infections. The genus Ruta is rich in essential oils, which predominantly contain aliphatic ketones, e.g., 2-undecanone and 2-nonanone, but lack any significant amounts of terpenes. Three Ruta species, Ruta chalepensis L., Ruta graveolens L., and Ruta montana L., have been extensively studied for the composition of their essential oils and several bioactivities, revealing their potential medicinal and agrochemical applications. This review provides a systematic evaluation and critical appraisal of publications available in the literature on the composition and bioactivities of the essential oils obtained from Ruta species and includes a brief outlook of the potential applications of nanote...
A new antimicrobial benzofuranone derivative, named, sonneratinone (1), was isolated from the end... more A new antimicrobial benzofuranone derivative, named, sonneratinone (1), was isolated from the endophytic fungus Aspergillus niger, obtained from the leaves of Sonneratia apetala, a mangrove plant from the Sundarbans. Whilst the fungal strain was identified by macroscopic, microscopic and molecular techniques, the structure of the new compound was elucidated by spectroscopic means, e.g., 1D and 2D NMR, and HRESIMS. Sonneratinone (1) showed considerable antimicrobial activity against Micrococcus luteus, Staphylococcus aureus and Candida albicans in the resazurin 96-well microtitre plate antimicrobial assay.
Centaurea asutro-anatolica Hub.-Mor. and C. kizildaghensis Uzunh., E. Dogan & H. Duman, two indig... more Centaurea asutro-anatolica Hub.-Mor. and C. kizildaghensis Uzunh., E. Dogan & H. Duman, two indigenous perennial herbs from the Turkish flora, belong to the medicinally important genus Centaurea L. (fam: Asteraceae), which comprises ca. 600 species worldwide. While various Centaurea species are well-known for producing alkaloids, flavonoids, lignans and terpenoids, there is no report on any thorough phytochemical work on any of these two species available to date. In continuation of our phytochemical and bioactivity studies on the Turkish Centaurea species, four flavonoids apigenin (1), apigenin 7,4’-dimethyl ether (2), genkwanin (3) and quercetin (4) were isolated from the methanol extracts of the aerial parts of C. austro-anatolica and C. kizildaghensis, for the very first time. The structures of the flavonoids were elucidated conclusively by spectroscopic means, i.e., UV, MS and 1D and 2D NMR data analyses. The distribution of these flavonoids (1-4) within the genus Centaurea and...
Oxysporone, possessing a 4H-furo(2,3-b)pyran-2(3H)-one structure, is a fungal metabolite, first i... more Oxysporone, possessing a 4H-furo(2,3-b)pyran-2(3H)-one structure, is a fungal metabolite, first isolated from Fusarium oxysporum. Later, this compound was also reported from the fungal genera, Diplodia, Pestalotia and Pestalotiopsis. Oxysporone was patented as an antibiotic for the treatment of dysentery, and its phytotoxic property has been well-established. Interesting biological and chemical properties of oxysporone make this compound attractive for its potential biotechnological applications in agriculture, especially as a new agrochemical with a lower environmental impact. However, it requires further extensive bioactivity screening looking at beyond its established phytotoxicity and preliminary antifungal property. It has a simple chemical structure (C7H8O4), and the hydroxyl group at C-4 provides options for synthesising numerous analogues by simply incorporating various functionalities at C-4, whilst keeping the main skeleton intact. This mini-review provides a critical over...
Xylaria species associated with termite nests or soil have been considered rare species in nature... more Xylaria species associated with termite nests or soil have been considered rare species in nature and the few which have been reported upon have been found to act as a rich source of bioactive metabolites. This study evaluated 10 ethyl acetate extracts of five new Xylaria species associated with termite nests or soil for their antioxidant activity, and cytotoxicity against different cancer and normal cell lines. DPPH and ABTS radical scavenging activities of the extracts demonstrated strong capacity with low IC50 values. The highest observed activities belonged to X. vinacea SWUF18-2.3 having IC50 values of 0.194 ± 0.031 mg/mL for DPPH assay and 0.020 ± 0.004 mg/mL for ABTS assay. Total phenolic content ranged from 0.826 ± 0.123 to 3.629 ± 0.381 g GAE/g crude extract which correlated with antioxidant activities. The high total phenolic content could contribute to the high antioxidant activities. Cytotoxicity was recorded against A549, HepG2, HeLa and PNT2 and resulted in broad spect...
Chalcones belong to the flavonoid class of phenolic compounds. They form one of the largest group... more Chalcones belong to the flavonoid class of phenolic compounds. They form one of the largest groups of bioactive natural products. The potential anticancer, anti-inflammatory, antimicrobial, antioxidant, and antiparasitic properties of naturally occurring chalcones, and their unique chemical structural features inspired the synthesis of numerous chalcone derivatives. In fact, structural features of chalcones are easy to construct from simple aromatic compounds, and it is convenient to perform structural modifications to generate functionalized chalcone derivatives. Many of these synthetic analogs were shown to possess similar bioactivities as their natural counterparts, but often with an enhanced potency and reduced toxicity. This review article aims to demonstrate how bioinspired synthesis of chalcone derivatives can potentially introduce a new chemical space for exploitation for new drug discovery, justifying the title of this article. However, the focus remains on critical apprais...
IntroductionOrganic molecules that interact with the cannabinoid receptors are called cannabinoid... more IntroductionOrganic molecules that interact with the cannabinoid receptors are called cannabinoids, which can be endogenous, natural or synthetic compounds. They possess similar pharmacological properties as produced by the plant, Cannabis sativa L. Before cannabinoids can be analysed, they need to be extracted from the matrices.ObjectiveTo review literature on the methods and protocols for the extraction of naturally occurring cannabinoids.MethodologyAn extensive literature search was performed incorporating several databases, notably, Web of Knowledge, PubMed and Google Scholar, and other relevant published materials. The keywords used in the search, in various combinations, with cannabinoids and extraction being present in all combinations, were Cannabis, hemp, cannabinoids, Cannabis sativa, marijuana, and extraction.ResultsIn addition to classical maceration with organic solvents, e.g. ethanol, pressurised solvent extraction, solvent heat reflux, Soxhlet extraction, supercritica...
Calanolides are tetracyclic 4-substituted dipyranocoumarins. Calanolide A, isolated from the leav... more Calanolides are tetracyclic 4-substituted dipyranocoumarins. Calanolide A, isolated from the leaves and twigs of Calophyllum lanigerum var. austrocoriaceum (Whitmore) P. F. Stevens, is the first member of this group of compounds with anti-HIV-1 activity mediated by reverse transcriptase inhibition. Calanolides are classified pharmacologically as non-nucleoside reverse transcriptase inhibitors (NNRTI). There are at least 15 naturally occurring calanolides distributed mainly within the genus Calophyllum, but some of them are also present in the genus Clausena. Besides significant anti-HIV properties, which have been exploited towards potential development of new NNRTIs for anti-HIV therapy, calanolides have also been found to possess anticancer, antimicrobial and antiparasitic potential. This review article provides a comprehensive update on all aspects of naturally occurring calanolides, including their chemistry, natural occurrence, biosynthesis, pharmacological and toxicological as...
Dhaka University Journal of Pharmaceutical Sciences, 2019
The current investigation was carried out to evaluate the antioxidant properties of ethanolic ext... more The current investigation was carried out to evaluate the antioxidant properties of ethanolic extract of Alternanthera bicolor and to assess the potential hypoglycemic effect of the extract in alloxan-induced diabetic mice. HPLC-DAD method was used to determine polyphenolic compounds present in the extract. Different in vitro assays (i.e. DPPH radical scavenging activity test, reducing power test, NO radical inhibition assay and scavenging of hydrogen peroxide) were used to determine the antioxidant potential of the plant. Antidiabetic activity was evaluated in alloxan-induced diabetic mice by glucose tolerance test and standard biochemical analyses. HPLC-DAD analysis of the extract confirmed the presence of (+)-catechin hydrate, caffeic acid, quercetin and kaempferol. A. bicolor showed potent antioxidant activities in DPPH radical, hydrogen peroxide and nitric oxide scavenging assays. Moreover, A. bicolor showed potent reducing power and dose-dependent increment of total antioxidan...
The 1D and 2D NMR analyses, notably, 1H, 13C PENDANT, HMQC, HMBC and NOESY, were carried out on t... more The 1D and 2D NMR analyses, notably, 1H, 13C PENDANT, HMQC, HMBC and NOESY, were carried out on two benzene derivatives, 2,4,5-trimethoxybenzaldehyde and 1-(2,4,5-trimethoxyphenyl)-ethanone, isolated from the dichloromethane extract of the stem bark of Pachypodanthium staudtii. The general toxicity of these compounds (LC50 = 32.6 and 80.5 μg/mL, respectively) was determined by the brine shrimp lethality bioassay.
Arbutin, a hydroquinone glucoside, has been detected in ca. 50 plant families, especially in the ... more Arbutin, a hydroquinone glucoside, has been detected in ca. 50 plant families, especially in the plants of the Asteraceae, Ericaceae, Proteaceae and Rosaceae families. It is one of the most widely used natural skin-whitening agents. In addition to its skin whitening property, arbutin possesses other therapeutically relevant biological properties, e.g., antioxidant, antimicrobial and anti-inflammatory, as well as anticancer potential. This review presents, for the first time, a comprehensive overview of the distribution of arbutin in the plant kingdom and critically appraises its therapeutic potential as an anticancer agent based on the literature published until the end of August 2022, accessed via several databases, e.g., Web of Science, Science Direct, Dictionary of Natural Products, PubMed and Google Scholar. The keywords used in the search were arbutin, cancer, anticancer, distribution and hydroquinone. Published outputs suggest that arbutin has potential anticancer properties a...
Advances in Pharmacological and Pharmaceutical Sciences
Plants act as a rich source of novel natural pesticides. In the backdrop of the recent revival of... more Plants act as a rich source of novel natural pesticides. In the backdrop of the recent revival of interest in developing plant-based insecticides, this study was carried out to investigate the pesticidal activity of Sundarban mangrove plants. A total of nine different plant parts from five plants, namely, Aegiceras corniculatum, Excoecaria agallocha, Heritiera fomes, Xylocarpus moluccensis, and Xylocarpus granatum, were extracted with methanol and tested for insecticidal activity against two common stored product pests Sitophilus oryzae and Sitophilus zeamais using direct contact feeding deterrent wafer disc method. Three bark extracts from A. corniculatum, E. agallocha, and H. fomes showed potent and statistically significant insecticidal activity against both S. oryzae and S. zeamais pests (80–100% mortality). All the active bark extracts were further fractionated using C-18 solid-phase extraction (SPE) columns and tested for their insecticidal activity against S. oryzae pest to i...
Ruta L. is a typical genus of the citrus family, Rutaceae Juss. and comprises ca. 40 different sp... more Ruta L. is a typical genus of the citrus family, Rutaceae Juss. and comprises ca. 40 different species, mainly distributed in the Mediterranean region. Ruta species have long been used in traditional medicines as an abortifacient and emmenagogue and for the treatment of lung diseases and microbial infections. The genus Ruta is rich in essential oils, which predominantly contain aliphatic ketones, e.g., 2-undecanone and 2-nonanone, but lack any significant amounts of terpenes. Three Ruta species, Ruta chalepensis L., Ruta graveolens L., and Ruta montana L., have been extensively studied for the composition of their essential oils and several bioactivities, revealing their potential medicinal and agrochemical applications. This review provides a systematic evaluation and critical appraisal of publications available in the literature on the composition and bioactivities of the essential oils obtained from Ruta species and includes a brief outlook of the potential applications of nanote...
A new antimicrobial benzofuranone derivative, named, sonneratinone (1), was isolated from the end... more A new antimicrobial benzofuranone derivative, named, sonneratinone (1), was isolated from the endophytic fungus Aspergillus niger, obtained from the leaves of Sonneratia apetala, a mangrove plant from the Sundarbans. Whilst the fungal strain was identified by macroscopic, microscopic and molecular techniques, the structure of the new compound was elucidated by spectroscopic means, e.g., 1D and 2D NMR, and HRESIMS. Sonneratinone (1) showed considerable antimicrobial activity against Micrococcus luteus, Staphylococcus aureus and Candida albicans in the resazurin 96-well microtitre plate antimicrobial assay.
Centaurea asutro-anatolica Hub.-Mor. and C. kizildaghensis Uzunh., E. Dogan & H. Duman, two indig... more Centaurea asutro-anatolica Hub.-Mor. and C. kizildaghensis Uzunh., E. Dogan & H. Duman, two indigenous perennial herbs from the Turkish flora, belong to the medicinally important genus Centaurea L. (fam: Asteraceae), which comprises ca. 600 species worldwide. While various Centaurea species are well-known for producing alkaloids, flavonoids, lignans and terpenoids, there is no report on any thorough phytochemical work on any of these two species available to date. In continuation of our phytochemical and bioactivity studies on the Turkish Centaurea species, four flavonoids apigenin (1), apigenin 7,4’-dimethyl ether (2), genkwanin (3) and quercetin (4) were isolated from the methanol extracts of the aerial parts of C. austro-anatolica and C. kizildaghensis, for the very first time. The structures of the flavonoids were elucidated conclusively by spectroscopic means, i.e., UV, MS and 1D and 2D NMR data analyses. The distribution of these flavonoids (1-4) within the genus Centaurea and...
Oxysporone, possessing a 4H-furo(2,3-b)pyran-2(3H)-one structure, is a fungal metabolite, first i... more Oxysporone, possessing a 4H-furo(2,3-b)pyran-2(3H)-one structure, is a fungal metabolite, first isolated from Fusarium oxysporum. Later, this compound was also reported from the fungal genera, Diplodia, Pestalotia and Pestalotiopsis. Oxysporone was patented as an antibiotic for the treatment of dysentery, and its phytotoxic property has been well-established. Interesting biological and chemical properties of oxysporone make this compound attractive for its potential biotechnological applications in agriculture, especially as a new agrochemical with a lower environmental impact. However, it requires further extensive bioactivity screening looking at beyond its established phytotoxicity and preliminary antifungal property. It has a simple chemical structure (C7H8O4), and the hydroxyl group at C-4 provides options for synthesising numerous analogues by simply incorporating various functionalities at C-4, whilst keeping the main skeleton intact. This mini-review provides a critical over...
Xylaria species associated with termite nests or soil have been considered rare species in nature... more Xylaria species associated with termite nests or soil have been considered rare species in nature and the few which have been reported upon have been found to act as a rich source of bioactive metabolites. This study evaluated 10 ethyl acetate extracts of five new Xylaria species associated with termite nests or soil for their antioxidant activity, and cytotoxicity against different cancer and normal cell lines. DPPH and ABTS radical scavenging activities of the extracts demonstrated strong capacity with low IC50 values. The highest observed activities belonged to X. vinacea SWUF18-2.3 having IC50 values of 0.194 ± 0.031 mg/mL for DPPH assay and 0.020 ± 0.004 mg/mL for ABTS assay. Total phenolic content ranged from 0.826 ± 0.123 to 3.629 ± 0.381 g GAE/g crude extract which correlated with antioxidant activities. The high total phenolic content could contribute to the high antioxidant activities. Cytotoxicity was recorded against A549, HepG2, HeLa and PNT2 and resulted in broad spect...
Chalcones belong to the flavonoid class of phenolic compounds. They form one of the largest group... more Chalcones belong to the flavonoid class of phenolic compounds. They form one of the largest groups of bioactive natural products. The potential anticancer, anti-inflammatory, antimicrobial, antioxidant, and antiparasitic properties of naturally occurring chalcones, and their unique chemical structural features inspired the synthesis of numerous chalcone derivatives. In fact, structural features of chalcones are easy to construct from simple aromatic compounds, and it is convenient to perform structural modifications to generate functionalized chalcone derivatives. Many of these synthetic analogs were shown to possess similar bioactivities as their natural counterparts, but often with an enhanced potency and reduced toxicity. This review article aims to demonstrate how bioinspired synthesis of chalcone derivatives can potentially introduce a new chemical space for exploitation for new drug discovery, justifying the title of this article. However, the focus remains on critical apprais...
IntroductionOrganic molecules that interact with the cannabinoid receptors are called cannabinoid... more IntroductionOrganic molecules that interact with the cannabinoid receptors are called cannabinoids, which can be endogenous, natural or synthetic compounds. They possess similar pharmacological properties as produced by the plant, Cannabis sativa L. Before cannabinoids can be analysed, they need to be extracted from the matrices.ObjectiveTo review literature on the methods and protocols for the extraction of naturally occurring cannabinoids.MethodologyAn extensive literature search was performed incorporating several databases, notably, Web of Knowledge, PubMed and Google Scholar, and other relevant published materials. The keywords used in the search, in various combinations, with cannabinoids and extraction being present in all combinations, were Cannabis, hemp, cannabinoids, Cannabis sativa, marijuana, and extraction.ResultsIn addition to classical maceration with organic solvents, e.g. ethanol, pressurised solvent extraction, solvent heat reflux, Soxhlet extraction, supercritica...
Calanolides are tetracyclic 4-substituted dipyranocoumarins. Calanolide A, isolated from the leav... more Calanolides are tetracyclic 4-substituted dipyranocoumarins. Calanolide A, isolated from the leaves and twigs of Calophyllum lanigerum var. austrocoriaceum (Whitmore) P. F. Stevens, is the first member of this group of compounds with anti-HIV-1 activity mediated by reverse transcriptase inhibition. Calanolides are classified pharmacologically as non-nucleoside reverse transcriptase inhibitors (NNRTI). There are at least 15 naturally occurring calanolides distributed mainly within the genus Calophyllum, but some of them are also present in the genus Clausena. Besides significant anti-HIV properties, which have been exploited towards potential development of new NNRTIs for anti-HIV therapy, calanolides have also been found to possess anticancer, antimicrobial and antiparasitic potential. This review article provides a comprehensive update on all aspects of naturally occurring calanolides, including their chemistry, natural occurrence, biosynthesis, pharmacological and toxicological as...
Dhaka University Journal of Pharmaceutical Sciences, 2019
The current investigation was carried out to evaluate the antioxidant properties of ethanolic ext... more The current investigation was carried out to evaluate the antioxidant properties of ethanolic extract of Alternanthera bicolor and to assess the potential hypoglycemic effect of the extract in alloxan-induced diabetic mice. HPLC-DAD method was used to determine polyphenolic compounds present in the extract. Different in vitro assays (i.e. DPPH radical scavenging activity test, reducing power test, NO radical inhibition assay and scavenging of hydrogen peroxide) were used to determine the antioxidant potential of the plant. Antidiabetic activity was evaluated in alloxan-induced diabetic mice by glucose tolerance test and standard biochemical analyses. HPLC-DAD analysis of the extract confirmed the presence of (+)-catechin hydrate, caffeic acid, quercetin and kaempferol. A. bicolor showed potent antioxidant activities in DPPH radical, hydrogen peroxide and nitric oxide scavenging assays. Moreover, A. bicolor showed potent reducing power and dose-dependent increment of total antioxidan...
The 1D and 2D NMR analyses, notably, 1H, 13C PENDANT, HMQC, HMBC and NOESY, were carried out on t... more The 1D and 2D NMR analyses, notably, 1H, 13C PENDANT, HMQC, HMBC and NOESY, were carried out on two benzene derivatives, 2,4,5-trimethoxybenzaldehyde and 1-(2,4,5-trimethoxyphenyl)-ethanone, isolated from the dichloromethane extract of the stem bark of Pachypodanthium staudtii. The general toxicity of these compounds (LC50 = 32.6 and 80.5 μg/mL, respectively) was determined by the brine shrimp lethality bioassay.
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Papers by Prof Lutfun Nahar