SYNERGISTIC EFFECT OF ANTI-OXIDANT, ANTI-TYROSINASE AND ANTI-BACTERIAL ACTIVITIES OF TRIDAX PROCUMBENS, LANTANA CAMARA, EUPHORBIA HIRTA AND THEVETIA PERUVIANA PLANT EXTRACTS FOR COSMETIC AND PERSONAL CARE APPLICATIONS

Objective: Herbal skin care products have become increasingly popular in the cosmeceutical industry. Skin care products are used to lighten the skin, improve the skin tone, treat pigmentation disorders and to combat the skin microflora. The approaches in development of skin care products have broadened widely in the recent years. One of the approaches is the utilization of a consortium of herbal extracts that have multiple benefits such as antimicrobial, anti-tyrosinase and antioxidant activities for their combined effects in skin care formulations. The present study is an effort to investigate the anti-tyrosinase, anti-oxidant and antibacterial properties in selected Malaysian plants viz. Tridax procumbens, Lantana camara, Euphorbia hirta and Thevetia peruviana towards their application in skincare and personal care formulation. The major objectives of the study are: to extract the bio-active principles from these plants with three different solvents, screen the extracts for anti-tyrosinase activity, anti-oxidant and anti-bacterial activities, evaluate the synergistic effect of polyherbal mix for the development a skincare formulation that has a combined effect of anti-tyrosinase, anti-oxidant and anti-bacterial activities. Methods: The crude extracts were screened for (i) anti-tyrosinase property by dopachrome method; (ii) anti-oxidant property by DPPH and FRAP assays and (iii) antimicrobial property using disc diffusion and broth dilution methods. Synergistic combination of specific plant extracts rich in anti-tyrosinase, antioxidant and antimicrobial properties were incorporated and evaluated for their benefits in the skincare cream. The skincare cream was evaluated for preservative efficacy by challenging it with test microorganisms: Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus as described in British Pharmacopoeia 2002. Results: The anti-oxidant activity of plant extracts were evaluated using DPPH and FRAP assays which were found to be correlated. Antioxidant activity was observed to be the highest in methanol extract of Euphorbia hirta and acetone extract of Euphorbia hirta. The polyherbal extract combination acted as the only preservative in the formulation and recorded 99% mortality of the loaded microorganisms in 7 days. Hence, the polyherbal extract combination would serve as natural preservative augmented with skin lightening benefits replacing the synthetic anti-tyrosinase, anti-oxidant and anti-bacterial compounds. Anti-tyrosinase activity has been reported in Tridax procumbens , Euphorbia hirta and Thevetia peruviana for the first time in this study. Conclusion : Remarkable anti-bacterial activity was observed in acetone extracts of Tridax procumbens . Synergistic effect of the polyherbal mix was confirmed for anti-oxidant activity and antibacterial activity. However, synergistic effect of the polyherbal mix for anti-tyrosinase activity was not significant in comparison to the individual activity of the selected plants.