Bioactive sesquiterpenes from an endophytic fungus Bipolaris sorokiniana isolated from a popular medicinal plant Costus speciosus

Abstract

Bipolaris sorokiniana, a fungal endophyte, was isolated from the leaves of Costus speciosus, a popular medicinal plant used to control diabetes. Fermentation of the fungus in potato dextrose broth and chromatographic purification of the ethyl acetate (EtOAc) extracts of the culture broth and mycelium yielded two rare sesquiterpenes helminthosporal acid (1) and helminthosporol (2), together with ergosterol. Compounds 1 and 2 showed a strong phytotoxic effect on lettuce seed germination and toxicity against brine shrimps. Compound 1 also showed antifungal activity. Complete assignments of 1 H and 13 C NMR data of compound 1 are described for the first time.

Bipolenins K–N: New sesquiterpenoids from the fungal plant pathogen Bipolaris sorokiniana

“…In addition, the activities of 1 , 6 – 10 and 12 against wheat seed germination were also tested, with 7 inhibiting germination at 100 ppm (Figure S41, Supporting Information File 1). This corresponds to a previous report of the inhibitory effects of 7 on lettuce seed germination [19]. This activity could be due to the presence of an aldehyde moiety in 7 .…”

Spot blotch disease of wheat: the current status of research on genetics and breeding

“…). Both these compounds are plant growth regulators and are known to inhibit seed germination and hypocotyls/radicle growth (Qader et al ., ). Sorokinianin is also a sesquiterpene, and shares the same carbon skeleton as prehelminthosporol.…”

Phytotoxic Secondary Metabolites from Fungi

“…They have a variety of biological activities including cytotoxic, antioxidant, antiviral, antimicrobial and phytotoxic activity [154,155]. Four phytotoxic sorbicillinoids (Figure 19) named bisvertinolone (193), demethyltrichodimerol (194), trichodimerol (195), and trichotetronine (also called bislongiqinolide 196) were isolated from the rice solid cultures of Ustilaginoidea virens (teleomorph: Villosiclava virens), the pathogen of rice false smut disease. These compounds were evaluated for their phytotoxic activity, and showed strong inhibition against the radicle and germ elongation of rice and lettuce seedlings.…”

“…Both helminthosporal acid (291) and helminthosporol (294) were also isolated from Bipolaris sorokiniana. These two compounds inhibited seed germination of lettuce [195]. Helminthosporal (292) isolated from Helminthosporium sativum was toxic to barley root explants by seedling growth assay.…”