Bioprospecting for antitumor molecules from marine actinomycetes

Executive summary of the Research work done under the project “Bioprospecting for antitumor molecules from marine actinomycetes”

Funding : University Grants commission, UGC, Govt, of India

Principal Investigator: Dr.Sajeevan T.P, Assistant professor, National Centre for Aquatic Animal health, CUSAT, Cochin-16

Marine environment constitutes rich and biologically productive region constituting most of the species of the world as a result of which there is a higher magnitude of scope for research and investigation to explore the potential of both marine organisms and marine microorganisms as producers of novel drugs. Of all the marine forms, marine actinomycetes remain the richest source of natural products since they have capabilities to produce compounds with interesting biological activities. Studies validate that marine actinomycetes are abundant in various ocean sediments. Hence, the present study was designed and directed towards discovery of antitumor compounds from marine actinomycetes, which could be used as potential anticancer compounds.

Salient findings of this study are as follows:

  • A total of 62 marine actinomycetes were isolated from different marine environment includes twenty nine isolates from the sediment samples collected from the South-West coast of Indian Ocean, three isolates from a marine sponge Mycale sp. and thirty isolates from Arctic Ocean Among the 5 different media tested for isolation of marine actinomyctes, Actinomycetes Isolation Agar (AIA) was found to be the most suitable medium for isolation of marine actinomyctes. In the preliminary in vitro anticancer screening assay with a single concentration (50 µg/mL), 20 isolates showed cytotoxicity. Among these positive isolates, 4 isolates were identified to be unique and showing complete in vitro growth inhibition was selected for further study. The four marine actinomycetes with potential anticancer activity, and identified using 16S rRNA gene sequence analysis, were designated as: Streptomyces MCCB 267, Streptomyces MCCB 246, Pseudonocardia MCCB 268, Streptomyces IC 50 determination of the crude extracts of selected Actinomycetes on NCI-H460 was performed and cytotoxicity was confirmed. Hoechst 33342 assay, TUNEL assay and Annexin V –PI double staining proved that cytotoxicity is NOT by necrosis but through induction of apoptotic pathways. The All the marine actinomycetes isolated in this study were deposited in the microbial culture collection of NCAAH. These resources could be bioprospected for other bioactivities such as antimalarial, antimicrobial, anti-inflammatory etc. for potential lead compounds.