Efficacy and Safety of a Facial Mask Containing Aquilaria crassna Leaf Extract: a Double-Blind Randomized Controlled Trial

Abstract

Aquilaria crassna Pierre ex Lecomte (Agarwood) is a common plant in Southeast Asia. Both A. crassna leaf extract and its component, mangiferin, have been reported as having antioxidant, anti-inflammatory and antiglycation activities. The objectives of this study were, first, to test the standardized aqueous extract of A. crassna leaves (eAC) and formulations containing eAC, for skin irritation, and second, to test the cosmetic efficacy of facial masks containing eAC via a double-blind, randomized, placebo-controlled trial. For the skin irritation tests, patches containing either 1% or 5% eAC in water, or 0.1% and 0.2% eAC formulation were applied to the skin and the extent of skin irritation was measured by the Mean Cumulative Irritation Index. To test the cosmetic efficacy, facial masks containing a formulation of 0.2% eAC, or a placebo formulation, were randomly applied to either the left or the right half of the face of the 33 participants for 8 weeks. The result showed that the formulae containing 0.1% and 0.2% eAC caused no skin irritation. However, higher eAC doses of 1% and 5% in water caused mild irritation. The efficacy study showed that the formulation of 0.2% eAC significantly increased skin hydration from 30.9±1.3 (baseline) to 39.6±1.4 at week 4 and 45.9±1.3 at week 8 (p=0.001), while the effect of the placebo facial mask was negligible. Skin elasticity was not affected by either treatment. In conclusion, eAC at appropriate concentrations improves skin hydration while having no adverse or toxic reactions, thus showing promise as a bioactive ingredient in cosmetic products.