New Sulphated Flavonoids and Larvicidal Activity of Helicteres velutina K. Schum (Sterculiaceae).

Abstract

Helicteres velutina K. Schum (Sterculiaceae), commonly known in Brazil as ‘pitó’, is traditionally used by indigenous peoples as insecticides and repellents. The present work reports on the the phytoconstituents from aerial parts of H. velutina and evaluation of the larvicidal potential of its extract. The compounds were isolated using chromatographic techniques and identified by NMR, IR and LC-HRMS. This study led to the isolation of a fatty acid, one aliphatic alcohol, four chlorophyll derivatives, one steroid, triterpenes, a lignan, and flavonoids, highlighting the new compounds in the literature, 5,4′-di-hydroxy-7-methoxy-8-O-sulphate flavone (mariahine) (15a) and 5,3′-di-hydroxy-7,4′-dimethoxy-8-O-sulphate flavone (condadine) (15b). The work presented here contributes to the chemotaxonomic knowledge of the Sterculiaceae family by describing the occurrence of sulphated flavonoids in this family for the first time. The crude ethanolic extract of H. velutina featured robust larvicidal activity against Aedes aegypti larvae, showing that the extract can be useful as a domestic larvicide, just as indicated by traditional use, to combat A. aegypti, a vector insect of severe viral diseases, such as dengue and Zika.