Lisboaeflavanonol A: A New Flavonoid Glycoside Obtained From Amazonian Eugenia Lisboae

Eugenia lisboae M.A.D. Souza (Myrtaceae) is a species found in the Amazon biome, recently described and has not yet been studied regarding its chemical properties. This study aims to identify the main chemical constituents of crude ethyl acetate and ethanolic extracts from E. lisboae leaves. These crude extracts were fractionated using chromatographic methods (LC and HPLC). The identified compounds are a triterpene (1), three organic acids (2 4), and two flavonoids (5 and 6). These structures were determined by analyzing the spectroscopic (NMR and MS) data. Compound 6 was named lisboaeflavanonol A {(-)-2R,3R-dihydrokampferol 3-O-beta-D-xylopyranosyl(1"'-> 2")-alpha-L-rhamnopyranoside}, undescribed in the literature. These were the first compounds described in this matrix, and the chemical composition is in line with chemistry of the Eugenia genus. In addition, preliminary molecular docking analysis indicated lisboaeflavanonol A as a potential inhibitor of 3-chymotrypsin-like cysteine protease (3CLpro) and RNA-dependent RNA polymerase (RdRp), which are important SARS-CoV-2 non-structural proteins (NSPs).