Inhibitory Effect of Major Terpenoids of Essential Oil from Agathosma betulina Leaves on Collagenase and Elastase Enzymes Involved in Skin Aging

Abstract

Abstract Collagenase and elastase enzymes that cause the degradation of collagen and elastase have both been implicated in skin aging. Agathosma betulina is a popular plant in South Africa used in aromatherapy and folk medicine but the scientific knowledge regarding its anti-aging activity is yet to be explored. This study aimed to investigate the roles of the essential oil of A. betulina leaves on skin aging and its inhibitory effect on collagenase and elastase activities. In this work, the chemical profiling of essential oils of A. betulina leaves was explored. The antioxidant activity of essential oil of A. betulina leaves at different concentrations (0.07–10 µg/mL) was assessed using standard assay methods for 1,1-dihenyl-2-picryhydrayl (DPPH) and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS). Standard procedures for elastase and collagenase assays were also employed to determine the anti-aging skin activity of the essential oil at the same concentrations. Gas chromatography-mass spectrometric analysis showed the presence of 43 constituents with menthone (29.2%), limonene (23.7%), and pulegone (8.4%) as the major compounds. The oil expressed strong radical scavenging activity against DPPH and ABTS radicals at higher concentrations, with over 90% inhibition, particularly at 2.5, 5, and 10 µg/mL compared to the control (butylated hydroxytoluene). The oil also demonstrated stronger inhibitory activity against elastase at higher concentrations (5 and 10 µg/mL) and concentration-dependent inhibitory activity against collagenase compared to the control (ursolic acid). The essential oil of A. betulina leaves could be a potential candidate for the cosmetic industry to retard skin wrinkles and other manifestations of skin aging particularly associated with extrinsic factors.