Heng, Y; Ban, J; Khoo, K; Sit, N
Cibotium barometz (L.) J.Sm. (Cibotiaceae) is a tropical tree fern and its rhizome is used in many traditional medicines. The hairs covering the rhizome are usually removed before use. This study aims to evaluate the rhizome hairs for phytochemical content, antioxidant and antimicrobial activities, as well as metabolites profiling of the ethyl acetate extract using gas chromatographyâmass spectrometry (GCâMS). The rhizome hairs were extracted sequentially using hexane, chloroform, ethyl acetate, ethanol, methanol, and water. Qualitative analysis indicates that the extracts contained anthraquinones, flavonoids, phenolics, tannins, phytosterols, and triterpenoids. The total phenolic and flavonoid contents of the extracts were 0.37â266 mg gallic acid equivalents/g sample and 4.57â113 mg quercetin equivalents/g sample, respectively. The ethyl acetate extract had the strongest antioxidant activity with the highest ferric-reducing antioxidant power (FRAP) value (35.1 mmol FeSO4 equivalents/mg sample), the highest oxygen radical absorbance capacity (ORAC) value (4.91 mmol Trolox equivalents/mg sample), and the lowest half-maximum effective concentration (6.50 μg/mL) for DPPH radical scavenging activity. A high positive correlation (P < 0.05) was found only between total phenolic content and FRAP (r = 0.9688) or ORAC (r = 0.9836), suggesting non-flavonoid polyphenols are the main contributors of antioxidant activity for the extracts. The ethyl acetate extract was the most active extract against bacteria and fungi, with minimum inhibitory concentration ranges of 0.31â1.25 mg/mL and 0.02â0.31 mg/mL, respectively. GCâMS analysis revealed the presence of 1-nonadecene, Z-5-nonadecene, octacosanol, and 1-tetracosanol/1-heneicosanol in the ethyl acetate extract which contributed partially to the antioxidant, antibacterial, and antifungal activities. The results indicate that the rhizome hairs is a good source of bioactive compounds with antioxidant and antimicrobial activities. © 2020 Elsevier B.V.