NGHIÊN CỨU KHẢ NĂNG KHÁNG VI KHUẨN PROPIONIBACTERIUM ACNES VÀ KHÁNG OXY HÓA CỦA ĐỊA Y PARMOTREMA TINCTORUM (PARMELIACEAE) ĐỊNH HƯỚNG ĐIỀU CHẾ KEM HỖ TRỢ ĐIỀU TRỊ MỤN TRỨNG CÁ

Abstract

Background: In recent studies, Parmotrema tinctorum has been shown to possess good antibacterial and antioxidant activities, but it has not yet received much attention or been exploited in the cosmetics industry. Objectives: Incorporating P. tinctorum lichen extract into a cream base and evaluating its antioxidant and Propionibacterium acnes antibacterial activities to develop a safe, natural acne treatment cream. Materials and methods: The lichen P. tinctorum was collected in Da Lat, Lam Dong. The extract was prepared using maceration assisted by ultrasonic waves with acetone as the solvent. The extract was incorporated into the cream base at concentrations of 1%, 3%, and 5% (w/w). Antibacterial activity was evaluated using the agar well diffusion method, and antioxidant activity was assessed based on DPPH free radical scavenging ability. Results: The samples of P. tinctorum cream are soft, smooth, homogeneous, and do not separate, with a pH range of 6-7. The 1% and 3% P. tinctorum creams are opaque white, while the 5% cream is light yellow. The diameter of the inhibition zone for P. tinctorum extract against P. acnes is 19,0 ± 1,0 mm at a concentration of 160 mg/mL. The 1% cream has a faint inhibition zone, while the 3% and 5% creams both show an inhibition zone with a diameter of 10,0 ± 1,0 mm at the same concentration. P. tinctorum extract effectively scavenges DPPH free radicals with an IC₅₀ value of 74,02 µg/mL. Conclusions: The P. tinctorum extract creams at 1%, 3%, and 5% demonstrate antibacterial activity against P. acnes. The 3% cream is selected as the product for acne treatment support and will be used in subsequent studies.