Miconia albicans (Melastomataceae) to treat Chikungunya viral infection: An effectual symptom-driven ethnomedicinal repurposing of an anti-inflammatory species?

Ethnopharmacological relevance: Miconia albicans (MA) is consumed all over the Brazilian territory as a remedy to treat rheumatoid arthritis and has been increasingly used to alleviate the deleterious symptoms caused by Chikungunya virus (CHIKV).Aim of the study: To investigate the effect of MA leaf and stem hydroethanolic extracts (LE and SE, respectively), their fractions enriched in triterpene acids or polyphenols as well isolated constituents, on CHIKV hosted in Vero cells.Materials and methods: Polyphenol profiles of LE and SE were dereplicated by HPLC-DAD-ESI-MS/MS, aided by standards. Polyphenol-rich (LEx and SEx) and triterpenic acid-rich (LOH and SOH) fractions were obtained in Amberlite XAD-4 and alkalinized 95% ethanol (EtOH) extraction, respectively. TPC and TFC were assessed by colorimetric methods. Three representative flavonoids and two triterpenic acids were quantified by HPLC. CHIKV load suppression was evaluated in Vero cells by real-time qRT-PCR at noncytotoxic concentrations.Results: Fifteen flavonoids were characterized in LE and SE. LEx presented isoquercitrin, quercitrin, rutin (0.49-1.51%) and quercetin. The TPC was 48 and 62 mg QE/g extract, and the TFC was 11.93 and 0.76 mg QE/g extract for LEx and SEx, respectively. LOH presented ursolic (15.3%) and oleanolic (8.0%) acids. A reduction (91-97%) in the CHIKV load was produced by the triterpene fraction, quercitrin and quercetin; the latter maintained the activity down to one twentieth of the tolerated concentration.Conclusion: M. albicans contains flavonoids and triterpenic acids that are effective against CHIKV, which might justify its use to alleviate sequelae of CHIKV infection. However, further investigations on the species and its active constituents are needed.