Structurally diverse indole alkaloids with cytotoxicity from Lonicera Japonica-associated endophytic fungus Penicillium ochrochloron YT2022-65

Abstract

Natural products, especially fungal secondary metabolites, have been served as valuable sources of drug leads in pharmaceutical industry. Medicinal plants-associated endophytic fungi possess a well-developed secondary metabolism. In this study, chemical investigation on Penicillium ochrochloron YT2022-65, an endophytic fungus associated with Lonicera Japonica, led to the isolation of six structurally diversified indole alkaloids, including a new one, namely peniochroloid A (1), as well as five previously reported alkaloids, flavonoid B (2), brocaeloid C (3), isoroquefortine C (4), roquefortine C (5), and dihydrocarneamide A (6). Their structures, including the absolute configuration of 1, were determined by a combined analysis of HRESIMS, NMR spectroscopic data, and calculation of the optical rotation. Their cytotoxicity against A549, HepG2, MCF-7, and THP-1 cell lines were evaluated in vitro. The new compound 1 was found to possess considerable cytotoxicity against MCF-7 and THP-1 cell lines with IC50 values of 10.2 and 11.0 μM, respectively.