Lorneic Acid Analogues from an Endophytic Actinomycete

Abstract

Our natural products discovery program utilizes endophytic actinomycetes associated with plants and employs biological assays and HPLC-based metabolite profiles as the preliminary screen to identify strains of interest, followed by large-scale fermentation and isolation, leading to new and/or bioactive natural products. Six new trialkyl-substituted aromatic acids, namely, lorneic acids E-J (1-6), together with two known analogues (7 and 8), were isolated and identified from the culture extract of Streptomyces sp. KIB-H1289, an endophytic actinomycete obtained from the inner tissue of the bark of Betula mandshurica Nakai. The structures were characterized by interpretation of their spectroscopic data, mainly 1D and 2D NMR. Among them, compound 5 contains a unique disulfide bond that is presumably derived from N-acetylcysteine. All isolated metabolites were evaluated for their inhibitory activity on tyrosinase.

Dimeric Pyranonaphthoquinone Glycosides with Anti-HIV and Cytotoxic Activities from a Soil-Derived Streptomyces

“…Soil-dwelling Streptomyces are a prolific source of bioactive compounds . In our continuous efforts to discover novel bioactive natural products, − Streptomyces sp. KIB3133, a strain isolated from the rhizospheric soil of tea ( Camellia sinensis ), caught our attention since its extract showed potent cytotoxicity against several cancer cell lines.…”

Two New 2(1H)-Pyrazinone Derivatives from the Plant Endophyte Streptomyces sp. KIB-H1992

“…More recently, Endophytes have attracted increasing attention in the discovery of natural products with potential physiological activity [4,5]. As part of our continuous efforts in screening for more secondary metabolites from endophytic microorganisms [6,7], two new 2(1H)-pyrazinone derivatives were obtained from the fermentation broth of endophytic actinomycete Streptomyces sp. KIB-H1992.…”

Benwamycins A–G, Trialkyl-Substituted Benzene Derivatives from a Soil-Derived Streptomyces

“…The diverse structures of microbial secondary metabolites include almost all functional groups in organic chemistry and are often difficult to access by chemical synthesis. From 1940 to 2010, 40% of bioactive microbial metabolites were isolated from actinomycetes, in which approximately 75% were obtained from the genus Streptomyces . − Consequently, Streptomyces remains an attractive source for bioactive metabolite discovery. − Recent advances in microbial genomics have unequivocally demonstrated that the biosynthetic potential of microbes is much higher than previously appreciated. , During our ongoing program on the chemical investigation of bioactive microbial secondary metabolites, − we isolated Streptomyces strain KIB-H1471 from a soil sample collected in Yuxi, Yunnan Province, China, in 2015. Subsequent high-performance liquid chromatography (HPLC) analysis of its extract highlighted a rich array of metabolites.…”