Studies On Chemical Constituents And Bioactivities Of Manihot Esculenta In Hainan

Cassava (Manihot esculenta Crantz) is one of the most important food crops in tropical regions of the world, being a staple source of energy carbohydrates for human consumption. In China, cassava was distributed in Hainan, Guangdong, Guangxi, Guizhou, Yunnan, Fujian, and Taiwan provinces, etc. The present paper discuss the chemical constituents and bioactivities of cassava collected in hainan.The chemical constituents of the volatile oils from the stems and leaves of cassava were analyzed by GC-MS.25 components, accounting for 83.53% of the oils from stems, and 22 components, accounting for 83.53% from the oils of leaves, were identified respectively. Bioassay of those two oils against Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) were carried out by paper disco diffusion method. The results showed that the volatile oil from stems possessed inhibitory activity towards Staphylococcus aureus, and the volatile oil from leaves possessed inhibitory activity towards MRSA. Cytotoxicity assay of the volatile oil from stems showed significant cytotoxicity against the K562 cell line with the IC50 values of 7.0μg/mL.An activity-directed fractionation and purification process was used to screen antioxidant fractions from the ethanol extract of cassava stems. The result suggested that the antioxidants were mainly contained in ethyl acetate fraction and n-butanol fraction. And the ethyl acetate fraction showed the greatest antioxidant activity, on which further investigation was focused.The ethyl acetate fraction was subjected to purification using column chromatography. and their structures were identified by physicochemical and spectroscopic methods (including NMR,2D-NMR, MS, et al.). Fifteen compounds were isolated from the stems of cassava in Hainan. And their structures were elucidated as Coniferaldehyde (1), Isovanillin (2), 6-Deoxyjacareubin (3), cholesterol (4),β-sitosterol (5), Scopoletin (6), Syringaldehyde (7), Pinoresinol (8),3,6-bis(4-hydroxy-3-methoxyphenyl)tetrahydrofuro[3,4-c]furan-1(3H)-one (9), Courmaric acid (10), Ficusol (11), Yucalexin P-15 (12), Balanophonin (13), Ethamivan (14) andβ-daucosterol (15), Compounds 1,2,3,7,8,9,10,11,13 and 14 were isolated from this plant for the first time.All the compounds were examined for their antioxidant activities by the DPPH method and ABTS method, and the results showed that phenolic compounds contributed to the antioxidant activity of ethyl acetate fraction. The cytotoxic activity of those compounds were tested by MTT assay, the result showed that compounds 1,2 and 13 has cytotoxic activity. And the antibacterial activities of those compounds were examined by the filter paper disc agar diffusion method. compounds 11 and 12 possessed effects on Staphylococcus aureus, which diameter of inhibition zone was 22.0 and 8.0 mm, respectively. Compounds 11 possessed effects on methicillin-resistant Staphylococcus aureus (MRSA), which diameter of inhibition zone was 14.0 mm.