Isolation of three new metabolites and intervention of diazomethane led to separation of compound 1 & 2 from an endophytic fungus, Cryptosporiopsis sp. depicting cytotoxic activity

The discovery of three new natural products (1, 4, and 5), one semi-synthetic derivative (3) along with two known compounds (2 and 6) were isolated from an endophytic fungus Cryptosporiopsis sp. The structural elucidations of 1–6 were authenticated by one-dimensional and two-dimensional nuclear magnetic resonance, mass spectroscopy, and X-ray diffraction analysis. Herein, we intervention of diazomethane as tool that help in the crystallization and isolation of inseparable mixtures of compounds 1 and 2. Compounds (1–6) were screened for cytotoxic activity against six cancer cell lines in which the 4-epi-ethisolide (2) exhibited moderate activity with IC50 values 11 µM in HL-60, whereas the compound 3 lost its cytotoxic potentiality, but it displayed moderate antimicrobial activity. The result illustrates that the methylene moiety in 2 plays significant role in cytotoxic potential.