Determination of phenolic compounds and evaluation of cytotoxicity in Plectranthus barbatus using the Allium cepa test

Abstract

Plectranthus barbatus, popularly known as Brazilian boldo or false boldo is mainly used for digestive problems. The aim of our study was to evaluate the proliferative and genotoxic potential of aqueous extracts obtained from fresh and dry leaves and stems of P. barbatus using the in vivo Allium cepa test. For the treatments, 6 g of fresh material was first weighed. This was then dried in the microwave, resulting in 0.9 g stems and 0.64 g leaves. The same amount of material was dried naturally at room temperature. We prepared the aqueous extracts by infusion of the leaves and decoction of the stems. Water was used as a negative control and glyphosate 1.5% as a positive control. The extracts were analyzed by high performance liquid chromatography (HPLC). Statistical analysis was performed using the Chi-square and Scott-Knott tests (p <0.05). The results showed that the extracts increased the cellular division of roots. No treatment found genotoxicity. The HPLC showed the predominance of isoquercitrin and kaempferol in the leaves, and isoquercitrin, kaempferol, and quercitrin in the stems. We concluded that the aqueous extracts from both leaves and stems of P. barbatus have proliferative and non-genotoxic activity on the cell division of A. cepa, which can be extrapolated to other eukaryotic cell types.