Natural products and biological activity from actinomycetes associated with Ilex pubescens Hook. & Arn

An endophytic actinomycetes, Streptomyces nanningensis, was -isolated from the leaves of Ilex pubescens Hook. et Arn. Five compounds were separated from the ethyl acetate extract of the fermentation broth of endophytic actinomycetes, and their structures were confirmed by utilising methods such as nuclear magnetic resonance, mass spectrometry, and literature references. These compounds were identified as Genistin (1), Esculetin (2), Ursolic acid (3), Chlorogenic acid (4), and Oleanolic acid (5). Compounds 1 and 4 showed inhibitory effects against Escherichia coli with minimum inhibitory concentrations (MIC) of 0.7815 mg/mL and 0.7815 mg/mL, respectively; Compound 4 demonstrated inhibitory effects against Candida albicans, with an MIC value of 0.7815 mg/mL. The results of in vitro antioxidant activity demonstrated that Compounds 1 and 4 exhibited scavenging activity against the DPPH free radical, with IC₅₀ values of 125 and 63 μg/mL, respectively.