野生桃金娘主要抗氧化成分及其抗氧化能力

本实验研究了野生桃金娘（Rhodomyrtus tomentosa）的抗氧化能力、总多酚含量、总黄酮含量、抗坏血酸含量和花青素类成分。采用超高效液相串联光电二极管阵列（photo-diode array，PDA）检测器和离子肼质谱法（ultra performance liquid chromatography coupled to photo-diode array and ion-trap mass spectrometry，UPLC-PDAIT-MS）鉴定花青素类化合物，通过高通量的自由基清除方法测定抗氧化能力。结果表明：野生桃金娘具有较高的抗氧化能力。每克桃金娘的1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl，DPPH）自由基清除能力相当于67.2 μmol的抗坏血酸和28.5 μmol没食子酸；过氧化氢自由基清除能力（PSC单位）相当于23.2 μmol的抗坏血酸和14.3 μmol没食子酸；2,2’-联氮双（3-乙基苯并噻唑啉-6-磺酸）二铵盐（2,2’-azinobis（3-ethylbenzothi azoline-6-sulfonic acid） ammonium salt，ABTS）自由基（ABTS+·）清除能力相当于30.4 μmol的抗坏血酸和7.8 μmol没食子酸；对三价铁的还原能力相当于28.7 μmol的抗坏血酸和3.1 μmol没食子酸。野生桃金娘的总多酚含量和总黄酮含量分别是4 976 mg 没食子酸/100 g（以干质量计）和49.7 mg儿茶酚/100 g（以干质量计），总抗坏血酸含量是9 mg/100 g（以鲜质量计）。总花青素含量相当于414 mg矢车菊素/100 g（以干质量计），共有飞燕草素3-O-葡萄糖苷等7 种花青素类化合物被鉴别出来。

Main Antioxidant Components and Antioxidant Activity of Wild Hill Gooseberry Fruits (Rhodomyrtus tomentosa) from Southern China

The ripe fruit of wild hill gooseberry (Rhodomyrtus tomentosa) was analyzed for its antioxidant activity, total
phenolics, total flavonoids, ascorbic acid contents, and anthocyanin composition. Ultra performance liquid chromatography
coupled to photo-diode array and ion-trap mass spectrometry (UPLC-PDA-IT-MS) was used to identify the anthocyanin
composition. The antioxidant activity was determined by high-throughput free radical scavenging assay. As a result, the wild
hill gooseberry had a higher antioxidant capacity. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity was
expressed as 67.2 μmol of ascorbic acid and 28.5 μmol of gallic acid equivalents per g of hill gooseberry. The peroxyl radical
scavenging capacity (PSC) was expressed as 23.2 μmol of ascorbic acid and 14.3 μmol of gallic acid equivalents per g of hill
gooseberry. The 2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity was expressed as
30.4 μmol of ascorbic acid and 7.8 μmol of gallic acid equivalents per g of hill gooseberry. The ferric reducing antioxidant power
(FRAP) was expressed as 28.7 μmol of ascorbic acid and 3.1 μmol of gallic acid equivalents per g of hill gooseberry. Total
phenolics and total flavonoids contents (on a dry weight basis) were 4 976 mg GAE/100 g md and 49.7 mg catechin/100 g md,
respectively, and total ascorbic acid content (on a fresh weight basis) was 9 mg/100 g mf. Total monomeric anthocyanin content (on
a dry weight basis) was 414 mg/100 g md. Seven anthocyanins including delphinidin 3-O-glucoside were identified. Cyanidin
3-O-glucoside was the most predominated form, followed by peonidin 3-O-glucoside and delphinidin 3-O-glucoside.