A New 2,2′-dipyridine and Its Analogues from Endophytic Streptomyces sp. KIB H017c with Potent Cytotoxicity

Abstract

A new 2,2′-dipyridyl compound 1, along with three known analogues (2–4), was isolated from the culture broth of endophytic Streptomyces sp. KIB H017c derived from Fragaria ananassa. Their structures were elucidated by analysis of 1D and 2D NMR as well as HRESIMS data, and comparison with literature data. The biological properties of all isolates were explored for antibacterial, antifungal and cytotoxic activity. All four compounds exhibited weak antifungal activity against Saccharomyces cerevisiae, and compound 4 exhibited weak antifungal activity against Penicillium decumbens ATCC 10436. Compound 3 displayed moderate cytotoxic activity against HL-60 (human myeloid leukemia), SMMC-7721 (hepatocellular carcinoma), A-549 (lung carcinoma), MCF-7 (breast adenocarcinoma), and SW480 (colon carcinoma) with IC50 values of 12.10, 11.15, 23.64, 31.13 and 14.62 μM, respectively. Compound 4 exhibited potent activity against A-549 (lung carcinoma), MCF-7 (breast adenocarcinoma), and SW480 (colon carcinoma) with IC50 values 0.88, 0.34 and 0.55 μM, respectively.