Phytotoxic activity and identification of chemicals constituents in Lonchocarpus cultratus (Vell.) A.M.G. Azevedo & H.C. Lima aerial parts (Fabaceae)

Abstract

Lonchocarpus cultratus (Vell.) A.M.G. Azevedo & H.C. Lima (Fabaceae) is a native tree species and from which flavonoids, triterpenes, alkaloid were isolated. In addition, potent antiproliferative activity of hexane fraction and chalcone, obtained from this plant, has been described in different cell lines of human tumors. However, no studies were found on the allelopathic and/or bioherbicidal action, using aerial parts of L. cultratus. Thus, the aim of the present work was to evaluate the allelopathic activity of methanol extract, fractions and compounds from aerial parts of L. cultratus. Dried aerial parts were extracted by exhausting extraction with methanol at room temperature, and the solvent was evaporated under reduced pressure providing the crude extract. The crude extract was partitioned in a liquid-liquid extraction and to obtain hexanic (HF), chloroform (CF), ethyl acetate (EAF), and hydromethanolic (HMF) fractions. The compounds were extracted from fractions through chromatographic methods. Crude extract and its fractions inhibited Lactuca sativa germination mean time (GMT) and germination speed índex (GSI), but not the germination percentage (GP) of Lactuca sativa. Crude extract and hexane fraction inhibited the hypocotyl growth of L. sativa seedlings and the other fractions inhibited the primary root of seedlings. Hexane, chloroform, and ethyl acetate fractions inhibited primary root growth of Euphorbia heterophylla. Chalcone 2’,4’-dihydroxy-5’-prenylchalcone, flavanone 8-prenylpinocembrin and alkaloid 4-hydroxy-N-methylproline were tested on lettuce early growth. Thirty-three metabolites were identified by UHPLC-MS/MS analysis, with flavonoid derivatives being the most abundant constituents.