Anti-arboviral activity and chemical characterization of hispidulin and ethanolic extracts from Millingtonia hortensis L.f. and Oroxylum indicum (L.) Kurz (Bignoniaceae).

L.f. and (L.) Kurz (Bignoniaceae) are native species from the Asian continent. They are popularly used in traditional medicine and their extracts are rich in flavonoids. In this work, ethanolic extracts of stems and leaves of these species were evaluated against the Chikungunya, Zika and Mayaro virus. The extracts were subjected to analysis by ultra-efficient liquid chromatography coupled to mass spectrometry. Additionally, leaves extract was fractionated, leading to the isolation of hispidulin. Anti-arboviral activity against the three viruses was detected for leaves extract with EC ranging from 37.8 to 134.1 µg/mL and for stems extract with EC ranging from 18.6 to 55.9 µg/mL. Hispidulin inhibited viral cytopathic effect of MAYV (EC value 32.2 µM) and CHIKV (EC value 78.8 µM). In LC-DAD-ESI-MS/MS analysis we characterized 25 flavonoids confirming once again the presence of these substances in extracts of these species.