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Various pre-treatment methods and three different media were employed for the isolation of bioactive actinomycetes from mangrove sediments of Andaman and Nicobar Islands, India. Sediments from four different sites of mangrove forest were collected and pre-treated by dry heat method, and the media were supplemented with cycloheximide 80 μg/mL and nalidixic acid 75 μg/mL. The mean actinomycetes population density in sediment samples were recorded as 22 CFU-10-6 /gm in KUA medium followed by 12 CFU-10-6 /gm in AIA medium and 8 CFU-10-6 /gm in SCA medium. A total of 42 actinomycetes were isolated, and all the isolates were evaluated for their antibacterial activity against pathogenic bacteria on two different media. Among 42 isolates tested, 22 species were found to be antibacterial metabolite producer against test bacteria namely, Staphylococcus aureus, Bacillus subtilis, Salmonella typhi and Klebsiella pneumoniae. Particularly, the actinomycete strains such as A101,

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Totally 192 actinomycetes colonies were isolated from 18 marine sediment samples of Palk Strait region of Bay of Bengal, India. Among them, 68 isolates were morphologically distinct on the basis of colour of spore mass, reverse side colour, aerial and substrate mycelia formation, production of diffusible pigment and sporophore morphology. Thirty-nine isolates were assigned to the genus Streptomyces, Actinopolyspora (10), Saccharopolyspora (7), Actinomadura (4), Nocardiopsis (3), Micromonospora (2), Actinomyces (1), Actinoplanes (1) and Microbispora (1). From these, 64 isolates with aerial mycelia, 65 isolates with substrate mycelia and 61 isolates had both aerial and substrate mycelia.

Totally 25 marine soil samples were collected from the region of Palk Strait of Bay of Bengal, Tamil Nadu, and were subjected to the isolation of actinomycetes. Sixty-eight morphologically distinct isolates were obtained and 37% (25) of them had antimicrobial activity. The potential producer was named as Streptomyces sp. VPTS3-1 and the phylogenetic evaluation on the basis of 16S rDNA sequence further categorized the organism as Streptomyces afghaniensis VPTS3-1. Further, the antimicrobial compound was extracted from the isolate using various solvents and the antimicrobial efficacies were tested against bacterial and fungal pathogens. In addition, in vitro optimization of parameters for the antimicrobial compound production revealed that the suitable pH as 7-8, the period of incubation as 9 days, temperature (30°C), salinity (2%), and starch and KNO 3 as the suitable carbon and nitrogen sources respectively in starch-casein medium.

The present study aimed at characterizing biological potentials of endophyte Aspergillus terreus JAS-2 isolated from Achyranthus aspera. Crude extracted from endophytic fungus JAS-2 was purified and chemically characterized by chromatographic and spectroscopic studies respectively. Spectral assignment of NMR (nuclear magnetic resonance) data, 1 H proton and 13 C carbon analysis along with FTIR data elucidated the structure of compound as 4,5-Dihydroxy-3-(1-propenyl)-2-cyclopenten-1-one. After purification and identification a set of experiment was conducted to explore efficacy of compound. Results revealed that on accessing the antifungal activity of compound, growth diameter of tested phytopathogenic fungi was reduced to 50% at higher concentration taken (10 µgµl −1 ). Compound exhibited in-vitro bacterial cell inhibition at 20 µgml −1 concentration along with moderate antioxidant behavior. Evaluation of anticancer activity against human lung cancer cell line (A-549) exhibited its IC 50 value to be 121.9 ± 4.821 µgml −1 . Further cell cycle phase distribution were analyzed on the basis of DNA content and evaluated by FACS (Fluorescence Activated Cell Sorting) and it was revealed that at 150 µgml −1 of compound maximum cells were found in sub G1 phase which represents apoptotic dead cells. Terrein (4, 5-Dihydroxy-3-(1-propenyl)-2-cyclopenten-1-one) a multi-potential was isolated from endophytic fungus JAS-2, from well recognized medicinal herb A. aspera. To best of our knowledge, this is the first report of "Terrein" from endophytic derived fungus. This compound had also exhibited anticancer and antifungal activity against human lung cancer cell line A-549 and Bipolaris sorokiniana respectively which is causal organism of many plants disease. Hence endophytes are serving as alternative sources of drug molecules.

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