Bioguided Fractionation and Isolation of Free Radical Scavenging Components from in Vitro Propagated Chinese Medicinal Plants Dendrobium tosaense Makino and Dendrobium moniliforme SW

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• 作者：Shu-Fung Lo ; Vanisree Mulabagal ; Chung-Li Chen ; Chao-Lin Kuo ; and Hsin-Sheng Tsay
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2004
• 出版时间：November 17, 2004
• 年：2004
• 卷：52
• 期：23
• 页码：6916 - 6919
• 全文大小：51K
• 年卷期：v.52,no.23(November 17, 2004)
• ISSN：1520-5118

文摘

This study was performed to investigate the free radical scavenging active components from in vitropropagated medicinal herbs of the genus Dendrobium, namely, Dendrobium tosaense Makino andDendrobium moniliforme SW, using a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical antioxidative assay.Seeds of the capsules derived after 12 weeks of hand-pollination germinated asymbiotically (50-74%) on half-strength Murashige and Skoog's (MS) basal medium with 3% sucrose and solidifiedwith 0.9% Difco agar. Active growth in the germinated seedlings was achieved by reculturing onfull-strength MS basal medium supplemented with 8% banana homogenate, 8% potato homogenate,8% coconut water, 1.5% sucrose, and 0.9% Difco agar. Healthy plantlets transferred to plastic trayscontaining moss or moss and tree fern successfully acclimatized (84-100%) in the greenhouse.Extracts were prepared from plants grown in the greenhouse for a period of 6 months. Methanolicextracts of D. tosaense and D. moniliforme scavenged DPPH at 95.9 and 83.4%, respectively, at aconcentration of 0.4 mg/mL. Therefore, methanolic solubles of D. tosaense and D. moniliforme weresubjected to bioguided fractionation and separation by column chromatographic methods individually.After chromatographic separation of these crude extracts, the obtained fractions (Dm 1, Dm 2, Dm3, Dt 1, Dt 2, and Dt 3) were tested for their activity. Among them, fractions Dm 2 and Dt 1 showedsignificant antioxidant activity by DPPH radical antioxidative assay. Active fractions were purifiedfurther by column chromatography and resulted in identification of the antioxidant components alkylferulates from D. moniliforme and quercetin from D. tosaense.Keywords: Dendrobium; radical scavenging activity; mass propagation; alkyl ferulates