PHÂN TÍCH THÀNH PHẦN HÓA HỌC VÀ BƯỚC ĐẦU XÁC ĐỊNH HOẠT TÍNH KHÁNG KHUẨN, KHÁNG NẤM CỦA TINH DẦU NGHỆ BÒ CẠP (Curcuma daknongensis)

Abstract

This study was conducted to determine the chemical composition and to preliminarily evaluate the antibacterial and antifungal activities of essential oils extracted from the rhizomes of Curcuma daknongensis, a newly discovered species of the Zingiberaceae family found in Đắk Nông Province, Viet Nam. The essential oils were obtained using two extraction techniques, namely hydrodistillation and supercritical CO₂ extraction. The volatile compounds were analyzed by headspace (HS) analysis and gas chromatography–mass spectrometry (GC/MS). The antibacterial and antifungal activities of the essential oils were evaluated using the agar well diffusion method against five bacterial strains, including Escherichia coli, Bacillus cereus, Salmonella typhimurium, Pseudomonas aeruginosa, and Staphylococcus aureus, as well as two fungal strains, Aspergillus flavus and Candida albicans. The results showed that the essential oil of Curcuma daknongensis contained more than 60 compounds, with the major constituents being saussurea lactone (21.36%), zerumbone (19.79%), camphene (15.57%), 1,8-cineole (13.48%), α-humulene (13.22%), and camphor (12.12%). Both essential oil samples exhibited inhibitory effects against the tested microorganisms. However, the essential oil obtained by hydrodistillation showed only moderate inhibitory activity, with inhibition zone diameters ranging from 8.2 to 13.0 mm for bacteria and from 11.0 to 20.0 mm for fungi. In contrast, the essential oil extracted by supercritical CO₂ showed stronger antibacterial and antifungal activities, particularly against S. typhimurium (17.0 mm), P. aeruginosa (15.0 mm), A. flavus (22.0 mm), and C. albicans (20.0 mm). These findings provide initial scientific evidence on the chemical composition and biological activities of Curcuma daknongensis essential oil and indicate the potential application of this species in natural food and pharmaceutical products.