A potential antiviral against COVID-19 obtained from Byrsonima coccolobifolia leaves extract.

In this study, we specifically focused on the crude methanolic leaf extract of Byrsonima coccolobifolia, investigating its antifungal potential against human pathogenic fungi and its antiviral activity against COVID-19. Through the use of high-performance liquid chromatography coupled with electrospray ionization ion trap tandem mass spectrometry, direct infusion electrospray ionization ion trap tandem mass spectrometry, and chromatographic dereplication procedures, we identified galloyl quinic acid derivatives, catechin derivatives, proanthocyanidins, and flavonoid glycosides. The broth dilution assay revealed that the methanolic leaf extract of B. coccolobifolia exhibits antifungal activity against Cryptococcus neoformans (IC50 = 4 µg/mL). Additionally, docking studies were conducted to elucidate the interactions between the identified compounds and the central residues at the binding site of biological targets associated with COVID-19. Furthermore, the extract demonstrated an in vitro half-maximum effective concentration (EC50 = 7 µg/mL) and exhibited significant selectivity (>90%) toward SARS-CoV-2.

Galloylquinic acid derivatives from Byrsonima fagifolia leaf extract and potential antifungal activity.

ETHNOPHARMACOLOGICAL RELEVANCE: Byrsonima fagifolia Niedenzu (Malpighiaceae) and other Byrsonima species are popularly employed in Brazilian traditional medicine in the form of preparations as cicatrizing, anti-inflammatory, and antimicrobial. AIM OF THE STUDY: To characterize the phytochemical profile of the hydromethanolic extract obtained from B. fagifolia leaves (BF extract) and to evaluate the toxicity and the antifungal activity. MATERIALS AND METHODS: The compounds from BF extract were isolated by HPLC and the structures were elucidated based on extensive analyses of 1D and 2D NMR spectra (HMQC, HMBC and COSY) data. The antifungal effect was determined by the broth microdilution method and the toxicity was evaluated on erythrocytes from sheep's blood and Galleria mellonella larvae. RESULTS: Phytochemical investigation of the BF extract led to the isolation and characterization of pyrogallol, n-butyl gallate, 3,4-di-O-galloylquinic acid, 3,5-di-O-galloylquinic acid, 3,4,5-tri-O-galloylquinic acid, and 1,3,4,5-tetra-O-galloylquinic acid. The BF extract showed high content of galloylquinic acid derivatives reaching more than twenty-times the quercetin derivatives content, according to the quantification by HPLC. These galloylquinic acid derivatives, obtained during this study, and quercetin derivatives, previously isolated, were submitted to the antifungal assays. The BF extract inhibited yeast growth mainly against Cryptococcus spp., at concentrations of 1-16 µg/mL, comparable to isolated compounds galloylquinic acid derivatives. However, the quercetin derivatives as well as quinic acid, gallic acid, and methyl gallate showed lower antifungal effect compared with galloylquinic derivatives. In addition, the BF extract had no hemolytic effect and no toxicity on G. mellonella. CONCLUSION: The phytochemical analysis revealed that galloylquinic acid derivatives are the major compounds in the leaves of B. fagifolia and they are associated to anti-cryptococcal activity and presented reduced toxicity.