铁皮石斛化学成分及其抗氧化活性研究

采用硫酸-苯酚法、Al Cl3比色法、酸性染料比色法测定铁皮石斛(Dendrobium officinale)花、叶、茎中多糖、黄酮、生物碱含量,通过DPPH和ABTS清除实验评价铁皮石斛花、叶、茎的水提物和乙醇提取物的体外抗氧化活性。结果表明,铁皮石斛不同部位的多糖含量茎>花>叶,黄酮含量花>叶>茎,生物碱在各个部位分布均较少。其中茎的多糖含量可达23.92%,花中黄酮含量可达1.847%。抗氧化能力评价表明,铁皮石斛花水提物、茎醇提物、花醇提物的DPPH自由基清除能力相对较好,半效应浓度(EC50)分别为410.4μg·mL^(-1)、454.1μg·mL^(-1)、573.2μg·mL^(-1);铁皮石斛茎醇提物、花醇提物、花水提物ABTS自由基清除能力相对较好,半效应浓度(EC50)分别为61.1μg·m L^(-1)、62.2μg·mL^(-1)、103.0μg·mL^(-1)。铁皮石斛花的提取物抗氧化活性整体优于叶和茎,醇提物抗氧化能力优于水提物。

The Chemical Constituents and Antioxidant Activities of Dendrobium officinale

Sulfuric acid phenol method, AlCl₃ method and acid dye colorimetry were used to determine the contents of polysaccharides, flavonoids and alkaloids in flowers, leaves and stems of Dendrobium officinale. DPPH and ABTS clearance test were used to evaluate the antioxidant activities in vitro of water extracts and ethanol extracts from flowers, leaves and stems of D. officinale. The results showed that the content of polysaccharide: stem>flower>leaf, flavonoid content: flower>leaf>stem. Alkaloids were less distributed in all parts. The content of flavonoids in flower was 1.847%, the content of polysaccharide in stem was 23.92%. The DPPH radical scavenging capacity was as follows: flower water extract, stem alcohol extract, flower alcohol extract, the half effect concentration (EC₅₀) were 410.4 μg·mL^-1, 454.1 μg·mL^-1, 573.2 μg·mL^-1, respectively. The ABTS radical scavenging ability was as follows: flower alcohol extract, flower alcohol extract, flower water extract, the half effect concentration (EC₅₀) were 61.1 μg·mL^-1, 62.2 μg·mL^-1, 103.0 μg·mL^-1, respectively. The antioxidant activity of D. officinale flower was better than that of leaves and stems, and the antioxidant capacity of ethanol extract was better than that of water extract.