Exploring the antiviral potential of justicidin B and four glycosylated lignans from Phyllanthus brasiliensis against Zika virus: A promising pharmacological approach.

BACKGROUND: Zika virus (ZIKV) is an emerging arbovirus that in recent years has been associated with cases of severe neurological disorders, such as microcephaly in newborns and Guillain-Barré syndrome in adults. As there is no vaccine or treatment, the search for new therapeutic targets is of great relevance. In this sense, plants are extremely rich sources for the discovery of new bioactive compounds and the species Phyllanthus brasiliensis (native to the Amazon region) remains unexplored. PURPOSE: To investigate the potential antiviral activity of compounds isolated from P. brasiliensis leaves against ZIKV infection. METHODS: In vitro antiviral assays were performed with justicidin B (a lignan) and four glycosylated lignans (tuberculatin, phyllanthostatin A, 5-O-ß-d-glucopyranosyljusticidin B, and cleistanthin B) against ZIKV in Vero cells. MTT colorimetric assay was used to assess cell viability and plaque forming unit assay to quantify viral load. In addition, for justicidin B, tests were performed to investigate the mechanism of action (virucidal, adsorption, internalization, post-infection). RESULTS: The isolated compounds showed potent anti-ZIKV activities and high selectivity indexes. Moreover, justicidin B, tuberculatin, and phyllanthostatin A completely reduced the viral load in at least one of the concentrations evaluated. Among them, justicidin B stood out as the main active, and further investigation revealed that justicidin B exerts its antiviral effect during post-infection stages, resulting in a remarkable 99.9 % reduction in viral load when treatment was initiated 24 h after infection. CONCLUSION: Our findings suggest that justicidin B inhibits endosomal internalization and acidification, effectively interrupting the viral multiplication cycle. Therefore, the findings shed light on the promising potential of isolated compounds isolated from P. brasiliensis, especially justicidin B, which could contribute to the drug development and treatments for Zika virus infections.

First report of phenolic compounds isolated from Inga stipularis DC. (fabaceae) leaves.

Several species of the Inga genus are used by Amazonian indigenous communities to treat injuries, pain and inflammations, which is directly related to the presence of phenolic compounds in these species. Many studies have addressed the phytochemical relevance of this genus, but they are still few considering the large number of species. Therefore, this study aimed to investigate the chemical composition of Inga stipularis leaves in order to find compounds with potential pharmacological application and economic interest. The developed method allowed the isolation and identification of 8 compounds in the ethanol extract of I. stipularis: eucryphin, neoastilbin, astilbin, neoisoastilbin, isoastilbin, quercitrin, engeletin and isoengeletin. Astilbin stands out for having been isolated directly from the fractionation of the extract by SPE with high yield. This study was a pioneer for I. stipularis and revealed the potential of the species as an abundant source of compounds of pharmacological and economic interest.