Are foliar extracts of mycorrhizal Hymenaea martiana toxic to human peripheral blood mononuclear cells?

Arbuscular mycorrhizal fungi (AMF) are known to enhance the accumulation of bioactive compounds with medicinal properties in plants. However, the potential cytotoxic effects of extracts from mycorrhizal plants on peripheral blood mononuclear cells (PBMC) remain unexplored. Therefore, this study aimed to verify the cytotoxic potential of foliar extract from Hymenaea martiana Hayne seedlings, either associated or not associated with AMF on PBMC. A greenhouse experiment was conducted with two treatments: a control group (without AMF) and a group inoculated with Acaulospora longula Spain and N.C. Schenck. After 148 days, leaves were collected to prepare aqueous extracts, and cytotoxicity of the extracts was assessed using the MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide) assay. Additionally, the antioxidant potential and the content of soluble carbohydrates, flavonoids, flavonols, flavonones, dihydroflavonols, and saponins were assessed. Hymenaea martiana seedlings associated with A. longula exhibited a more than 50% increase in the accumulation of phenolic compounds compared to the control. However, no toxicity was detected for PBMC under any of the conditions evaluated. This study provides the first evidence of the effect of mycorrhizal plant extracts on human blood cells, highlighting their potential safety for medicinal and cosmetic applications.