Topical Creams for Acne and Melasma: In-Vitro and In-Vivo Investigations of Active Botanical Extract Formulations

Abstract

Background : Melasma is a common facial pigmentary disorder. A multifactorial contribution is suggested in the etiology of melasma and ultraviolet (UV) irradiation plays an important role in melasma. Plants have been used worldwide as medicine and have been reported to show anti-melasma activities. Cutaneous infections especially acne of the skin are one of the often faced dermatological diseases worldwide. Topical therapy is an attractive choice for the treatment of the cutaneous infections due to its advantageous such as targeting of drugs to the site of infection and reduction of the risk of systemic side effects. Materials and Methods : Methanolic extract of Hippophae rhamnoides and Cassia fistula were effectively extracted and phytochemically screened. The antioxidant activities of the plant extracts were measured by Nitric oxide radical scavenging assay, DPPH radical scavenging assay, Hydroxyl radical scavenging assay and Superoxide radical scavenging assay. Total phenolic contents observed spectophotometrically. Stable creams, F1 (Hippophae rhamnoides extract), F2 (Cassia fistula extract) and F3 (placebo) of o/w type were prepared using Paraffin oil as oily phase, Tween 80 and Span 20 as the emulsifiers while distilled water as the aqueous phase. 5% crude plant extract was used in F1 and F2 while F3 was without the plant extract. All these creams were kept at four different storage conditions i.e., 8oC, 25oC, 40oC and 40oC with 75% Relative Humidity for a period of two months to evaluate their stability characteristics. Human volunteers were used for in-vivo assessment of F1, F2 and F3 to evaluate their effects on human skin. Different skin parameters like Skin Melanin (for melasma effects), Skin Sebum contents (for acne effects), Skin Trans epidermal water loss (TEWL) and Stratum corneum water contents (for moisturizing effects) and Surface evaluation of living skin (SELS) parameters related to skin aging were measured at different time intervals for three months. For acne and melasma effects, instrumental readings, visual observation as well as photographs were taken while other parameters were observed only by instrumental readings. XIX The results obtained were compared with the zero hour readings and the statistical tools of ANOVA (Kruskal–Wallis tests) and Dunnett Multiple comparisons post test were used in the statistical analysis to evaluate the changes produced. Results : Both plants extracts showed appreciable antioxidant potential and statistically insignificant differences (P>0.05) were observed among the triplicates in different systems of antioxidant activity evaluation. The antioxidant activities were more when methanol was used as extracting solvent and maceration as extraction method. The expected pharmaceutical stability of emulsions was achieved from 2 months in-vitro study period. Results of an electrical conductivity confirmed that an outer phase is water. A significant (P≤0.05) decrease in the level of melanin was produced by F1 and F2. The difference between pre and post-treatment levels of melanin was statistically significant (P = 0.05). In case of skin sebum contents, a significant (P ≤ 0.05) decrease was observed for both F1 and F2. The difference between pre and post-treatment levels of sebum contents was statistically significant (P=0.004). F1 and F2 showed significant (p<0.0001) effects on SELS parameters i.e., skin wrinkles (SEw), skin smoothness (SEsm), skin scaliness (SEsc) and skin roughness (SEr). The results were supported by 3D images of human skin after applications of respective creams. Stratum corneum water contents were increased and Trans epidermal water loss (TEWL) was decreased significantly (p<0.05) supporting the results of SELS parameters. Conclusions : As a conclusion creams with 5% plant extracts could be effective, safe and well-tolerated topical medications for melasma (hyperpigmentation), acne vulgaris and dry skin conditions.