Assessment of Photoprotective, Antioxidant and Anti-Skin Cancer Activities of Leaf Extracts of Certain Medicinal Plants

Abstract

Plant extracts acquiring antioxidant potential have recently been used for topical applications for significant protection against ultra violet (UV)-induced sunburn. The current study was conducted for screening Pluchea discoridis (Asteracea), Lawsonia inermis (Lythraceae), Aloe vera (Liliaceae) and Eucalyptus camaldulensis (Myrtaceae) for their photoprotective, antioxidant and anti-skin cancer properties. Multivariate data analysis based on spectrophotometric evaluation of major secondary metabolites was performed. Each plant had its specific pattern of metabolites. P. discoridis and E. camaldulensis were separated from other plants due to their high content of secondary metabolites where P. discoridis was discriminated by high content of flavonoids and saponins. E. camaldulensis, was discriminated by high content of phenolics and tannins. Different concentrations of plant extracts were read for absorbance at UVB spectrum. Sun protection factors (SPFs) were calculated. The highest concentration (10 mg/mL) of P. discoridis extract had the highest SPF, i.e., 23.94±0.98. The antioxidant activity using 2,2-Diphenyl-1-picryl-hydrazyl (DPPH) assay revealed that P. discoridis and L. inermis extracts had the best free radical scavenging activity with DPPH at 100 µg/mL of 85.69 ± 1.8 and 85.35 ± 2.5%, respectively. Human skin tumor cell line (A431) was incubated with the plant extracts. P. discoridis had the best anti-skin cancer activity of lowest LC50 value. The effect induced by the P. discoridis extract was also identical to that of the standard chemotherapeutic drug (doxorubicin). The present study revealed that P. discoridis is a promising plant for use in sunscreen formulations and anti-skin cancer treatment.