Avaliação da atividade antioxidante e efeito sobre a melanogênese de extratos das folhas de Passiflora nitida Kunth

Abstract

Pigmentary disorders such as melasma, freckles, and ephelides have motivated the search for natural products with potential for skin whitening. Given that the main regulatory enzyme of melanin production, tyrosinase can be inhibited by polyphenols and antioxidants, extracts from leaves of Passiflora nitida Kunth, which have been reported as rich in polyphenols and have antioxidant effects, can act as inhibitors of melanogenesis. This study aimed to know the total phenols, the antioxidant effect on tyrosinase, the cytotoxicity and the effect on melanin content of extracts from leaves of P. nitida. Were assessed extracts aqueous by infusion (EAI), aqueous by maceration (EAM), hydroethanolic (EHE) and ethanolic (EE). The EAM showed higher antioxidant activity by DPPH method and by the inhibition of lipid peroxidation and tyrosinase. The percentages of phenolic compounds found in the extracts were EAM = 5.63 ± 0.06%; EAI = 5.10 ± 0.04%, EHE = 3.97 ± 0.08%, EE = 3.35 ± 0, 17%. The median inhibitory concentration (IC50) of DPPH by the extracts were EAM = 38.99 ± 1.56 mg / mL, EHE = 44.16 ± 1.69 mg / mL, EAI = 45.26 ± 0.96 mg / mL, EE = 48.44 ± 0.66 mg / mL and the IC50 of gallic acid was AG = 0.80 ± 0.03 mg / mL. The inhibition of lipid peroxidation reaction at 120 minutes were BHT = 67.55 ± 1.66%, EAI = 56.29 ± 2.63%, EAM = 60.98 ± 2.07%, EHE = 45.04 ± 3 22%, EE = 23.22 ± 3.83%. The extracts also inhibited the tyrosinase which IC50 of kojic acid, the EAI, EAM, EHE and EE respectively were: 0.001 ± 1, 475 ± 28, 440 ± 27, 879 ± 32, 901 ± 29 mg / mL. The cytotoxicity of EAM on NIH 3T3 fibroblasts, melanoma B16F10 and Melan-a melanocyte was time dependent. Was lower for fibroblasts and melanocytes than melanoma. The EAM showed no antioxidant activity in NIH 3T3. EAM at concentrations of 10 and 25 mg / ml in B16F10 induced increase of melanin content to 196 ± 15% and 217 ± 20% respectively and in Melan-a concentrations of 6.25, 12.50 and 25 mg / ml reduced the melanin content to 90 ± 8, 84.8 ± 0.6 and 54 ± 4% respectively. Thus, one can say that EAM was able to reduce the level of melanin in melanocytes, with greater cytotoxicity for melanoma than for fibroblasts and melanocytes.