New cytochalasin from Rosellinia sanctae‐cruciana, an endophytic fungus of Albizia lebbeck

Aim To explore the potential of Rosellinia sanctae‐cruciana an endophytic fungus associated with Albizia lebbeck for pharmaceutically important cytotoxic compounds. Methods and Results One novel cytochalasin, named jammosporin A (1) and four known analogues (2–5) were isolated from the culture of the endophytic fungus R. sanctae‐cruciana, harboured from the leaves of the medicinal plant A. lebbeck. Their structures were elucidated by extensive spectroscopic analyses including one‐dimensional and two‐dimensional nuclear magnetic resonance data along with MS data and by comparison with literature reports. In preliminary screening the ethyl acetate extract of the fungal culture was tested for cytotoxic activity against a panel of four cancer cell lines (MOLT‐4, A549, MIA PaCa‐2 and MDA‐MB‐231), and found to be active against MOLT‐4 with an IC50 value of 10 μg ml−1. Owing to the remarkable cytotoxic activity of the extract the isolated compounds (1–5) were evaluated for their cytototoxicity against the MOLT‐4 cell line by MTT assay. Interestingly, compounds 1–2, 4 and 5 showed considerable cytotoxic potential against the human leukaemia cancer cell line (MOLT‐4) with IC50 values of 20·0, 10·0, 8·0 and 6·0 μmol l−1, respectively, while compound 3 showed an IC50 value of 25 μmol l−1. This is the first report of the existence of this class of secondary metabolites in R. sanctae‐cruciana fungus. Conclusion This study discovered a novel compound, named jammosporin A, isolated for the first time from R. sanctae‐cruciana, an endophytic fungus of A. lebbeck with anticancer activity against the MOLT‐4 cell line. Significance and Impact of the Study Rosellinia sanctae‐cruciana represents an interesting source of a new compound with bioactive potential as a therapeutic agent against a human leukaemia cancer cell line (MOLT‐4).