Comparative bioactivities of leaf and stem extracts of Houttuynia cordata Thunb.: Antioxidant, anti-inflammatory and antibacterial properties

Houttuynia cordata Thunb. is a medicinal plant widely used in traditional medicine and known for its diverse bioactive secondary metabolites. However, differences in metabolite composition between plant tissues and their functional implications remain unclear. This study assessed whether tissue-specific secondary metabolite profiles in H. cordata leaves and stems are associated with differences in antioxidant, anti-inflammatory and antibacterial activities. The botanical identification of the plant material was confirmed by matK gene sequencing. Gas chromatography-mass spectrometry (GC-MS) analysis revealed tissue-specific phytochemical distribution, with leaves enriched in biologically active compounds, whereas stems contained a greater number of detected compounds, indicating higher chemical diversity based on compound distribution within H. cordata. Both extracts exhibited dose-dependent anti-inflammatory activity through inhibition of nitric oxide (NO) production in RAW 264.7 macrophages; the stem extract showed stronger inhibitory potency, while the leaf extract demonstrated higher cell viability. The leaf extract also consistently exhibited higher antioxidant capacity in 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis       (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and ferric reducing antioxidant power (FRAP) assays. Furthermore, the leaf extract exerted stronger antibacterial activity and a broader inhibitory spectrum against Cutibacterium acnes, particularly among isolates from moderate to severe acne patients. These findings suggest that H. cordata may be associated with multiple biological effects related to bacterial growth, oxidative stress and inflammation, highlighting its potential relevance for developing herbal dermatological applications.