山荆子中根皮苷和黄酮含量的测定及其乙醇提取物的抗氧化活性

Contents of phloridzin and flavonoids in Malus baccata (Linn.) Borkh and antioxidant activity of its ethanol extract

【目的】测定山荆子鲜叶、茎皮和果中根皮苷及阴干的果实和叶中黄酮的含量,并比较阴干叶和果实乙醇提取物的抗氧化活性。【方法】采用超声波辅助甲醇提取山荆子鲜叶、茎皮和果实中的根皮苷,用高效液相色谱法测定提取物中目标产物的含量;用超声波辅助乙醇提取山荆子阴干叶和果实中的黄酮,用亚硝酸钠-硝酸铝-氢氧化钠法测定其叶和果实中的黄酮含量,并通过清除DPPH、ABTS自由基和还原力比较研究其乙醇提取物的抗氧化活性。【结果】山荆子鲜叶、茎皮和果实中的根皮苷含量分别为(12.00±3.60),(21.60±6.10)和(1.18±0.15)mg/g;阴干的叶和果实中黄酮含量分别为(4.78±0.62)和(0.68±0.04)mg/g。在清除DPPH自由基、ABTS自由基活性及还原力方面,山荆子阴干叶乙醇提取物较果实的抗氧化活性强。【结论】超声波辅助提取技术结合HPLC法测定山荆子叶、茎皮和果实中根皮苷含量操作简单,重复性好,结果准确。山荆子阴干叶和果实的乙醇提取物都具有较强的抗氧化活性,且叶乙醇提取物的抗氧化活性较强。

【Objective】This study aimed to determine the contents of phloridzin in leaves,bark and fruits and the contents of flavonoids in shady dried leaves and fruits of Malus baccata,and to compare the antioxidant activities of the ethanol extracts from dried leaves and fruits.【Method】Phloridzin was extracted by ultrasonic-assisted methanol method from leaves,bark and fruits of M.baccata and was quantified by HPLC.Flavonoids were extracted by ultrasonic-assisted ethanol method from shady dried leaves and fruits and were determined by NaNO2Al（NO3）3 NaOH method.The antioxidant activities of ethanol extracts from shady dried leaves and fruits of M.baccata in scavenging of DPPH and ABTS radicals and reducing power were assessed as well.【Result】Contents of phloridzin in M.baccata leaves,bark and fruits were （12.00±3.60）,（21.60±6.10） and （1.18±0.15） mg/g,respectively.Contents of flavonoids in shady dried leaves and fruits of M.baccata were （4.78±0.62） and （0.68±0.04） mg/g,respectively.The ethanol extract from M.baccata leaves had stronger antioxidant activity in scavenging of DPPH and ABTS radicals and reducing power than that from fruits.【Conclusion】Determination of phloridzin and flavonoids contents in M.baccata by ultrasonic-assisted extraction method with HPLC was simple and accurate.The ethanol extracts from shady dried leaves and fruits of M.baccata had strong antioxidant activities,and the ability of extract from leaves was stronger.