Md. Hossain Sohrab

Antimicrobial and cytotoxic constituents from leaves of Sapium baccatum

Six compounds, namely, Lupeol (1), Betulin (2), beta-Taraxerol (3), Taraxerone (4), Stigmasterol (5) and beta-Sitosterol (6) were isolated from the petroleum ether extract of the leaves of Sapium baccatum based on spectroscopic evidence. Lupeol (1), Betulin (2) and Stigmasterol (5) were isolated for the first time from this plant. The cytotoxic potential of the different solvent extracts (methanol, petroleum ether, carbon-tetrachloride and dichloromethane); six column fractions (F-4, F-7, F-10, F-12, F-18 and F-22) of petroleum ether extract and three pure compounds 1, 4 and 6 were determined by using brine shrimp lethality bioassay. The LC50 of all the tested samples were showed to be lethal to brine shrimp nauplii. However, petroleum ether, carbon-tetrachloride extract, column fractions F-4 and F-18 of petroleum ether extract and pure compound 6 showed quite potent activity in brine shrimp lethality bioassay with LC50 1.33, 1.35, 1.40, 1.58 and 1.58 microg/ml, respectively. These result suggested that they might be contain antitumor or pesticidal activity. Further, the methanol extract and four column fractions (F-7, F-12, F-18 and F-22) of petroleum ether showed significant activity against the tested microorganisms.

Cytotoxic and antibacterial naphthoquinones from an endophytic fungus, Cladosporium sp.

Objective Endophytes have the potential to synthesize various bioactive secondary metabolites. The aim of the study was to find new cytotoxic and antibacterial metabolites from endophytic fungus, Cladosporium sp. isolated from the leaves of Rauwolfia serpentina (L.) Benth. ex Kurz. (Fam: Apocyanaceae). Materials and methods The endophytic fungus was grown on potato dextrose agar medium and extracted using ethyl acetate. Secondary metabolites were isolated by chromatographic separation and re-crystallization, and structures were confirmed by 1H NMR, 13C NMR and mass spectroscopic data. The cytotoxicity was determined by WST-1 assay and brine shrimp lethality bioassay, while antibacterial activity was assessed by disc diffusion method. Results Two naphthoquinones, namely anhydrofusarubin (1) and methyl ether of fusarubin (2), were isolated from Cladosporium sp. The isolated compounds 1 and 2, by WST-1 assay against human leukemia cells (K-562) showed potential cytotoxicity with IC50 values of 3.97 μg/mL and 3.58 μg/mL, respectively. Initial screening of crude ethyl acetate extract and column fractions F-8 and F-10 exhibited noticeable cytotoxicity to brine shimp nauplii with LC50 values of 42.8, 1.2 and 2.1 μg/mL, respectively. Moreover, the isolated compound 2 (40 μg/disc) showed prominent activities against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Bacillus megaterium with an average zone of inhibition of 27 mm, 25 mm, 24 mm and 22 mm, respectively and the activities were compared with kanamycin (30 μg/disc). Conclusion Our findings indicate that anhydrofusarubin (1) and methyl ether of fusarubin (2) might be useful lead compounds to develop potential cytotoxic and antimicrobial drugs.

Cytotoxic Naphthoquinone and Azaanthraquinone Derivatives from an Endophytic Fusarium solani

Bioactivity-guided fractionation of the ethyl acetate extract obtained from the culture of the endophytic fungus Fusarium solani resulted in the isolation of one new naphthoquinone, 9-desmethylherbarine (1), and two azaanthraquinone derivatives, 7-desmethylscorpinone (2) and 7-desmethyl-6-methylbostrycoidin (3), along with four known compounds. Their structures were elucidated by spectral analysis, as well as a direct comparison of spectral data with those of known compounds. Azaanthraquinones 2 and 3 showed cytotoxic activity against four human tumor cell lines, MDA MB 231, MIA PaCa2, HeLa, and NCI H1975. A molecular docking study suggested DNA interactions as the mode of action of these naphthoquinones and azaanthraquinones.

Synthesis of barbituric acid derivatives using microwave irradiation method and in vitro evaluation of antimicrobial and cytotoxic activity.

Article history: The research work was involved in rapid and efficient procedure for the attachment of barbituric acid with arylidene acetophenone under microwave irradiation (MWI) and conventional heating. The result showed that the time was reduced from the conventional 24 hours to 5-10 minutes. In conventional heating, the yield of the compounds 2a-2e were very poor (75-81%), but in MW methods the yields were observed 96.48-98% which was comparatively too high. The structures of the compounds were characterized by FT-IR, 1 H-NMR spectral data. The antimicrobial and cytotoxic activities of the synthesized compounds were also investigated. Staphylococcus aureus, Bacillus megaterium, Escherichia coli and Pseudomonas aeruginosa revealed the zone of inhibition were 6-12 mm where sample concentration was 100 μg/disc. However, cytotoxic analysis, the mortality 47-95% were appeared when sample concentration were 0.78-25 (μg/ml) and more than 50 (μg/ml) concentration showed 100% mortality. The presence of a reactive and unsaturated ketone function in synthesized compounds was found to be responsible for their potential antimicrobial and cytotoxic activity.

Endophytic Fusarium solani: A rich source of cytotoxic and antimicrobial napthaquinone and aza-anthraquinone derivatives

Graphical abstract

Anti‐MRSA activity of oxysporone and xylitol from the endophytic fungus Pestalotia sp. growing on the Sundarbans mangrove plant Heritiera fomes

Heritiera fomes Buch.‐Ham., a mangrove plant from the Sundarbans, has adapted to a unique habitat, muddy saline water, anaerobic soil, brackish tidal activities, and high microbial competition. Endophytic fungal association protects this plant from adverse environmental conditions. This plant is used in Bangladeshi folk medicine, but it has not been extensively studied phytochemically, and there is hardly any report on investigation on endophytic fungi growing on this plant. In this study, endophytic fungi were isolated from the surface sterilized cladodes and leaves of H. fomes. The antimicrobial activities were evaluated against two Gram‐positive and two Gram‐negative bacteria and the fungal strain, Candida albicans. Extracts of Pestalotia sp. showed activities against all test bacterial strains, except that the ethyl acetate extract was inactive against Escherichia coli. The structures of the purified compounds, oxysporone and xylitol, were elucidated by spectroscopic means. The anti‐MRSA potential of the isolated compounds were determined against various MRSA strains, that is, ATCC 25923, SA‐1199B, RN4220, XU212, EMRSA‐15, and EMRSA‐16, with minimum inhibitory concentration values ranging from 32 to 128 μg/ml. This paper, for the first time, reports on the anti‐MRSA property of oxysporone and xylitol, isolation of the endophyte Pestalotia sp. from H. fomes, and isolation of xylitol from a Pestalotia sp.

Fusaproliferin, a Fungal Phytotoxin Shows Rapid and Potent Cytotoxicity against Pancreatic Cancer Cell Lines

Nazia Hoque 1,3,4, Choudhury Mahmood Hasan 2, Md. Sohel Rana 3, Amrit Varsha5, Md. Hossain Sohrab 4*and Khondaker Miraz Rahman 5* 1 Department of Pharmacy, East West University, Dhaka, Bangladesh 2 Department of Pharmaceutical Chemistry, University of Dhaka, Dhaka-1000, Bangladesh 3 Department of Pharmacy, Jahangirnagar University, Savar, Dhaka, Bangladesh 4 Pharmaceutical Sciences Research Division (PSRD), BCSIR Laboratories, Dhaka,

Medicinal values of aquatic plant genus Nymphoides grown in Asia: A review

Nymphoides is an aquatic genus consisting about 50 species, of which few were accepted as traditional medicinal plants in Asia. The literature review revealed that Nymphoides species are widely used in Ayurvedic medicine as a popular drug, i.e. Tagara. They are also utilized by the traditional local healers of different Asian countries to treat various diseases, like convulsion, jaundice, fever, headache, etc. According to the in vivo and in vitro pharmacological studies, Nymphoides species have been claimed to possess major biological activities like anticonvulsant, antioxidant, hepatoprotective, cytotoxic, antitumor, etc. Biochemical profiling of different aquatic plants of this genus revealed the presence of some important phytochemicals as polyphenolic component, flavonoids, triterpenes, carbohydrates, glycosides, etc. Several valuable bioactive compounds including ephedrine, coumarin, secoiridoid glucosides, methyl quercetin, ferulic acid, foliamenthoic acid, etc. were also known to be isolated and identified from different Nymphoides species. The aim of this review is to analyze the published report based on the medicinal values of different Asian Nymphoides species, to provide the updated information about the ethnomedicinal, pharmacological as well as the phytochemical properties for the first time.

Antimicrobial activity of kojic acid from endophytic fungus Colletotrichum gloeosporioides isolated from Sonneratia apetala, a mangrove plant of the Sundarbans

Objective: To isolate and evaluate the antimicrobial activity of the active principle(s) from the ethyl acetate (EtOAc) extract of endophytic fungus Colletotrichum gloeosporioides (C. gloeosporioides) isolated from Sonneratia apetala. Methods: Water agar technique was used to isolate the fungus, and both microscopic and molecular techniques were used for identification of the strain. Potato dextrose broth was used to grow the fungus in large-scale. Reversed-phase preparative HPLC analysis was performed to isolate the major active compound, kojic acid. The EtOAc extract and kojic acid were screened for their antimicrobial activity against two Gram-positive and two Gram-negative bacteria as well as a fungal strain using the resazurin 96-well microtitre plate antimicrobial assay. Results: The fungus C. gloeosporioides was isolated from the leaves of Sonneratia apetala. Initial identification of the fugal isolate was carried out using spore characteristics observed under the microscope. Subsequently, the ITS1-5.8S-ITS2 sequencing was employed for species-level identification of the fungus C. gloeosporioides. Five litres of liquid culture of the fungus produced approximately 610 mg of a mixture of secondary metabolites. Kojic acid (1) was isolated as the main secondary metabolite present in the fungal extract, and the structure was confirmed by 1D, 2D NMR and mass spectrometry. The EtOAc extract and compound 1 exhibited considerable antimicrobial activity against all tested microorganisms. Whilst the minimum inhibitory concentration (MIC) values from the EtOAc extract ranged between 2.4× 10-4 mg/mL and 2.5 mg/mL, those of kojic acid (1) were between 0.125 mg/mL and 1 mg/mL. The EtOAc extract and kojic acid (1) were most active against Pseudomonas aeruginosa (MIC = 2.4×10-4 mg/mL) and Micrococcus luteus (MIC = 0.125 mg/mL), respectively. Conclusions: The results revealed that the endophytic fungus C. gloeosporioides could be a good source of commercially important kojic acid, which exhibited antimicrobial properties.