Capsaicin production by Alternaria alternata, an endophytic fungus from Capsicum annum; LC–ESI–MS/MS analysis

A capsaicin (1) producing endophytic fungus was isolated from Capsicum annum. Two compounds including one (i.e., 3) were also isolated. 1 and 3 were quantified by (MRM) LC–SI–MS/MS. 3 displayed range of cytotoxicity against human cancer cell lines and induced apoptosis by mitochondrial-dependent pathway in HL-60 cells. •Capsaicin (1) producing endophytic fungus from Capsicum annum isolated.•Isolated two compounds including one new viz., 3.•Compound 1 and 3 quantified by (MRM) LC–ESI–MS/MS.•Compound 3 displayed cytotoxicity against a panel of human cancer cell lines.•Compound 3 induced apoptosis by mitochondrial-dependent pathway in HL-60 cells. Alternaria alternata, an endophytic fungus capable of producing capsaicin (1) was isolated from Capsicum annum. The endophyte was found to produce capsaicin upto three generations. Upscaling of the fermentation broth led to the isolation of one known and one compound characterized as 2,4-di-tert-butyl phenol (2) and alternariol-10-methyl ether (3) respectively. Compound 1 and 3 were identified and quantified using liquid chromatography-electrospray ionization tandem mass spectrometry (LC–ESI–MS/MS) system through multiple reaction monitoring (MRM). Furthermore, compound 3 displayed a range of cytotoxicity against a panel of human cancer cell lines and was found to induce apoptosis evidenced by Hoechst staining and loss of mitochondrial-membrane potential in HL-60 cells.