Antimicrobial activity of Phyllanthus Emblica fruit extract and its cosmetic application

Abstract

Fruit extract from Phyllanthus emblica L., a native plant in Thailand, possesses several biological activities including antimicrobial and antityrosiness activities. Development of a cosmetic product containing emblica fruit extract is not only increase economic values of this native plant but also provides an alternative choice of natural anti-acne product for consumers. In this study, fruit extract powder from two different sources, a commercially available emblica extract and an in-house emblica extract (ESDE), was extracted with acetone, methanol and ethyl acetate. The marc from ethyl acetate was sequentially extracted with acetone and methanol. Each fraction was characterized for their antimicrobial activities (such as MIC) and their chemical constituents. The phenolic compounds, mainly gallic acid, present in each fraction was evaluated using HPLC technique and the Folin-Ciocalteu reagent. Gel containing ESDE was developed in the presence of sodium metabisulfite, sodium benzoate, and citrate buffer pH 3.0. The gel containing ESDE was further evaluated for its physical and chemical stability at 30 ± 2 ℃, 75 ± 5 %RH for 1 month. Finally, the anti-acne efficacy of the gel containing ESDE was evaluated on 25 patients. ESDE and its fractions contained more phenolic content (15.77-29.92%, w/w) than the commercially available emblica extract and its fractions. MIC of ESDE was 10 mg/mL while other fractions did not show obvious antibacterial activities against S. aureus ATCC 25923 and 29 clinical isolates due to their limited water solubility. Further analysis of data from previous study of the peak area and time profile of ESDE in citrate buffer pH 3.0 stored at 30 ± 2 ℃ for 1 month showed the increment of gallic acid and peak no.1, the decrement of peak no.2, 5 and 6 and the consistent of peak no.3. Interestingly, peak no.6 decreased dramatically within a week and the observed inhibition zone against S. aureus was also decreased. Gel containing emblica extract (GCE) was translucent with yellow color. The color was change from yellow to brown within 1 week and eventually dark brown within 1 month. During 1 month storage at ± 2 ℃ and 75 ± 5 % RH, the pH was observed to be 3.24 + 0.06, the viscosity changed from 1238 + 75.60 to 1040 + 21.79 cP and gallic acid content increased from 0.06 to 0.09 % w/w. The peak area and time profile of GCE was similar to that of ESDE in citrate buffer. GCE was tested its anti-acne efficacy for 1 month and 1% clindamycin gel was used as a positive control. The individual acne reduction from week 0 to week 4 was significantly different, p<0.05. At the end of each week, mean acne reduction between two groups was not different, p>0.05.