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Crude extracts of Sedum formosanum N.E.Br. obtained from n-butanol partition (BP) and isopropanol salting-out pretreatment (ISP) were analyzed using antioxidation assays. The results indicated that the extract from ISP contained more potent antioxidants and thus exhibited more antioxidant activity in all the assays. The superoxide radical-scavenging activity and inhibition of nitric oxide radicals achieved after ISP were 3.65 and 2.18 times higher than those achieved through BP, respectively. Eight bioactive natural products were isolated and identified according to an analysis of antioxidation activity in different fractions of the ISP crude extract, namely three cyanophoric glycosides 1–3, three flavonoids 4–6 and two phenolic compounds (7 and a new compound 8). Among them, compounds 5 and 6 exhibit the highest antioxidation capability, and the ISP is suitable for obtaining compounds 5 and 6 using HPLC chromatograms. Therefore, ISP is an excellent extraction technology that can be used to extract antioxidant compounds in the nutraceutical and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

Abstract: Seven flavonoid glycosides (1–7) and one theasaponin (8) were isolated from the defatted Camellia oleifera seeds using the isopropanol salting-out pretreatment (ISP) technique, followed by column chromatography. Among them, compounds 5, 7, and 8 are new compounds. The comparison of oxygen radical absorbance capacity (ORAC) of crude extracts extracted by the n-butanol partition (BP) with those extracted by the ISP showed that the latter method yields eight times greater scavenging capacities than that of the former approach. Besides, ISP exhibited almost twice the extraction efficiency than that of BP. ORAC and Trolox equivalent antioxidant capacity (TEAC) analysis revealed that the most potent antioxidants are compounds 1 and 2, which exhibited 1.78 and 1.41 times higher antioxidant activity than that of Trolox, respectively. These results indicated that the ISP approach improves the extraction efficiency in the isolation of potent antioxidants, making the defatted C. oleifera seeds valuable in the food additive industry. [Copyright &y& Elsevier]

Abstract: The purpose of this research was to investigate a salting-out procedure for isolating four flavonoid glycosides from defatted Camellia oleifera seeds. The procedure included extraction with 80% methanol, methanol removal and addition of an equal amount of hydrophilic isopropanol and salt to separate the isopropanol fraction from the water layer. Using successive column chromatography, kaemferol-3-O-[2-O-β-d-glucopyranosyl-6-O-α-l-rhamnopyranosyl]-β-d-glucopyranoside (compound 1), kaemferol-3-O-[2-O-β-d-xylopyranosyl-6-O-α-l-rhamnopyranosyl]-β-d-glucopyranoside (compound 2), naringenin-7-O-[β-d-xylopyranosyl(1→6)][β-d-glucopyranosyl(1→3)-α-l-rhamnopyranosyl(1→2)]-β-d-glucopyranoside (compound 3) and naringenin-7-O-β-d-xylopyranosyl(1→6)-β-d-glucopyranoside (compound 4) were obtained. The structure of compound 3, a new flavanone glycoside, was analyzed using UV, FT-IR, 1H NMR, 13C NMR and HR-FAB-MS. Quantification using high-performance liquid chromatography (HPLC) demonstrated that defatted C. oleifera seed cake contains 7.92, 17.7, 2.23 and 1.06mg/g of the four compounds. The extraction efficiencies of the four compounds were increased by 23.17%, 7.59%, 48.67% and 47.22% from those obtained with n-butanol partition extraction. This new extraction technique is simpler, faster and less expensive than the traditional extraction method. Accordingly, this salting-out method can potentially replace the existing one. [Copyright &y& Elsevier]