The anti-aging potential of medicinal plants in Cameroon - Harungana madagascariensis Lam. and Psorospermum aurantiacum Engl. prevent in vitro ultraviolet B light-induced skin damage

Abstract

IntroductionPlants are used by the populations of Foumban (West Region) and Nkol Anga’a (Center Region) for skin care in Cameroon, Central Africa. In this study, the anti-aging potential of the medicinal plants were investigated by evaluating their in vitro antioxidant, anti-elastase and anti-tyrosinase activities followed by the analysis of their protective effect on ultraviolet B light-induced oxidative stress. MethodsAntioxidant potential to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydrogen-hydroxyl (OH°), reduce potassium ferrocyanate and phosphomolybdenum and inhibit lipid peroxidation (LP) was assessed while the anti-elastase and anti-tyrosinase activities were determined spectrophotometrically. The protective potential of the most active extracts were determined on ultraviolet B light-induced oxidative stress in fibroblasts and melanoma cells by measuring the mRNA levels of Nrf-2 and HO-1 ResultsTwenty-six medicinal plants species belonging to sixteen families were stock-listed. The crude extracts of Harungana madagascariensis and Psorospermum aurantiacum possessed high total polyphenol content. Likewise, the antioxidant activity of both plants was comparable to that of ascorbic acid in all the studied oxidative models. Tested at 100 μg/mL, these extracts were found to inhibit the activity of elastase at 100 and 77.58% respectively. Both extracts exhibited low inhibitory activity on tyrosinase as compared to ascorbic acid while the isolated hexane and methanol fractions demonstrated strong antioxidative activities. The hexane fraction of P. aurantiacum induced significant (p < 0.01) up-regulation of antioxidant genes (Nrf-2 and HO-1). ConclusionThe above cited plants exhibited high antioxidative, anti-tyrosinase and anti-elastase activities and, their active compounds may be promising for skin care.