Bioactivity-Guided Isolation, Antimicrobial and Cytotoxic Evaluation of Secondary Metabolites from Cladosporium tenuissimum Associated with Pinus wallichiana

Cladosporium tenuissimum, an endophyte, was isolated from Pinus wallichiana growing in the Western Himalayas of Lolab Valley (Kashmir India) and analysed for its secondary metabolite composition. Column chromatography of the culture broth lead to the isolation of three bioactive molecules viz; (3S, 5S, 11S)-trihydroxydodecanoic acid, scytalone and o-hydroxyphenyl acetone. The stereochemistry of (3S, 5S, 11S)-trihydroxydodecanoic acid was deduced from pandangolide. Pandangolide has been isolated from Cladosporium species and its stereochemistry is known. The isolated constituents were evaluated for cytotoxic and antimicrobial potential against MCF-7, T47D, MDA-MB-231 cell lines and ATCC 29213, ATCC 25922, IIIM 25, MTCC 4748 strains. (3S, 5S, 11S)-trihydroxydodecanoic acid exhibited significant cytotoxic activity against the human breast cancer cell line (MCF-7) with an IC50 of 15 mu g/ml. o-Hydroxyphenyl acetone displayed prominent antimicrobial activity against Bacillus cereus IIIM 25 (Gram positive) and Escherichia coli ATCC 25922 (Gram negative) with IC50 of 23.3 mu g/ml and 43.7 mu g/ml respectively. o-Hydroxyphenyl acetone is being reported for the first time from any natural source while as (3S, 5S, 11S)-trihydroxydodecanoic acid and scytalone for the first time from C. tenuissimum.