Bioactivities and promising active compounds of Etlingera pavieana (Pierre ex Gagnep) R.M.Sm. rhizome extract for dermatological applications

The rhizome of Etlingera pavieana (EE), traditionally used in Southeast Asian medicine, was evaluated for its antimicrobial, antioxidant, and anti-inflammatory properties. The ethanolic extract was tested against Cutibacterium acnes and Staphylococcus epidermidis using well diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), biofilm formation, and cell surface hydrophobicity assays. Antioxidant activity was measured via DPPH radical scavenging, and anti-inflammatory effects were assessed using protein denaturation assays. Cytotoxicity was evaluated on human dermal fibroblasts using the MTT assay. Major phenolic compounds were identified by HPLC and tested for antibacterial activity. The EE extract exhibited significant antibacterial activity against C. acnes, with an inhibition zone of 24.00 ± 1.73 mm and an MBC/MIC ratio of 4, confirming its bactericidal effect. It also inhibited biofilm formation and reduced cell surface hydrophobicity. The extract demonstrated antioxidant and anti-inflammatory activities and was noncytotoxic to dermal cells. HPLC identified 4-methoxycinnamyl p-coumarate (MCC) and p-coumaric acid (PCA) as major phenolics, both of which inhibited C. acnes more effectively than S. epidermidis, with MCC showing superior antibacterial efficacy. This study is the first to report the inhibitory effects of MCC and PCA against C. acnes, highlighting their contribution to the extract’s efficacy. The EE extract, with its effective bioactivities and low cytotoxicity, holds promise as a natural ingredient in skincare products for managing microbial infections and inflammation.