ABSTRACT Aristolochia plants are notable from an ethnopharmacological viewpoint, but the relevance of these species for medicinal purposes has been debated because of their inherent toxicity. The convergence of these contrasting realities can be readily achieved using bioconversion methods, which have been shown to be useful tools for numerous applications, including the detoxification of biomass. In this context, methanolic extracts of leaves from Aristolochia triangularis and Aristolochia gibertii, as well as the feces of Battus polydamas larvae fed with leaves from these plants, were prepared, and their cytotoxic activities were evaluated on a human fibroblast cell line (GM07492). The leaf extracts were found to be cytotoxic, leading to reductions of 42.1 and 33.8% on cell viability, respectively, while the fecal extracts were considered inactive. In addition to evidencing the cytotoxicity of A. triangularis and A. gibertii, these findings demonstrated a potential bioconversion strategy for obtaining aristolochiaceous extracts with reduced toxicity using the larvae of a specialist phytophagous insect, thus renewing expectations in relation to the pharmacological importance of Aristolochia spp. The results were also ecologically relevant, as B. polydamas larvae were found to be able to detoxify compounds from host plants.

RESUMO: O extrato aquoso de folhas de Aristolochia triangularis mostrou atividade sobre larvas de Artemia salina, com um DL50 de 370,6 µg/mL. Em experimentos com sementes de Allium cepa, o extrato provocou uma redução de 51,26% no índice de germinação, inibiu o crescimento radicular médio e foi citotóxico nas concentrações de 668 e 2.000 µg/mL. Sua atividade antioxidante foi adicionalmente avaliada nesta pesquisa e o valor de poder redutor de íons férrico foi de 391,2 µM/g. Tal propriedade benéfica para a saúde pode ser parcialmente atribuída ao conteúdo de compostos fenólicos totais, espectrofotometricamente determinada como 52,67 mg/g. A ocorrência de citotoxicidade sugeriu cautela ao consumir chás de folhas de A. triangularis para propósitos medicinais, e igualmente revela a necessidade por estudos adicionais para investigar os efeitos adversos deles.

ABSTRACT: The aqueous extract of Aristolochia triangularis leaves showed activity against Artemia salina larvae, with an LD50 of 370.6 µg/mL. In experiments with Allium cepa seeds, the extract caused a 51.26% reduction in the germination index, inhibited mean root growth, and was cytotoxic at concentrations of 668 and 2,000 µg/mL. Its antioxidant activity was additionally assessed in this research and the ferric reducing antioxidant power value was found to be 391.2 µM/g. Such health-beneficial property can be attributed partly to the total phenolic content, spectrophotometrically determined as 52.67 mg/g. The occurrence of cytotoxicity suggested caution when consuming teas from A. triangularis leaves for medicinal purposes, and equally reveals the need for further studies to investigate their adverse effects.