Antioxidant Activity, Total Phenolic and Flavonoid Contents, and Cytotoxicity Evaluation of Bougainvillea Xbuttiana

Objective: Bougainvillea xbuttiana is widely distributed in Mexico and it used as an analgesic in folk medicine. The aim of this study was to investigate the effect of five ethanolic extracts of Bougainvillea xbuttiana from different colours on cell and to quantify the potential of antioxidant activity, the total phenolic and flavonoids contents, all these in order to find possible sources for future novel antioxidant and pharmaceutical formulations. Methods: The effect of aerial part (flowers) of B. xbuttiana extracts from different colours such as orange-1 (BxbO1), orange-2 (BxbO2), rose (BxbR), violet (BxbV) and white (BxbW) were determined on cells by viability and vacuolization assays. The cellular viability activity was determined by taking the lyses percentage and the vacuoles formation. The antioxidant activity was performed by 2,2 ́-diphenyl-1-pierylhydrazyl (DPPH) and ferric reducing power (FRAP) assays. The total yield of phenolic and flavonoids contents was determined using spectrophotometer methods. Results: In this study, the effect of Bxb extracts on cells was shown by cytotoxicity percentage and vacuoles formation. The highest cytotoxic activity was observed when HeLa cells were exposed to BxbO1 and BxbO2 extracts. With respect to vacuoles formation the highest percentage of vacuoles formation was observed when the HeLa cells were exposed to BxbR. The phytochemical screening of ethanolic extracts of B.xbuttiana from different colour revealed the antioxidant activity with ranking order for the antioxidant activity index was BxbO2 = BxbR > BxbW > BxbO1 > BxbV. The ranking order for the reduction capacity was BxbO2 = BxbR > BxbW = BxbV > BxbO1. The total phenolic content ranged from 14.68 to 28.89 of dry weight of extract, expressed as gallic acid equivalents, and the ranking order was BxbO2 > BxbR > BxbW > BxbV > BxbO1. The total flavonoid contents varied from 59.13 to 129.38 expressed as EQmg/g dry weight and the ranking order was BxbV > BxbO2 = BxbO1 > BxbR > BxbW. Conclusions: Data from present results show that aerial part (flowers) of Bougainvillea xbuttiana possesses significant free radical scavenging properties colour-dependent manner, and clear correlation exists between the strong antioxidant activity, and phenolic, and flavonoids contents. The results suggest that Bxb can be regarded as promising candidates for natural plant sources of antioxidants with high value.