The aim of this study was to compare the phenolic compound profiles and antioxidant capacities of eight varieties of longan (Dimocarpus longan Lour.) planted in the middle and upper Yangtze River area. The total polyphenols content (TPC) and total flavonoids content (TFC) of dried longan pulp ranged from 1.07 ± 0.05 to 1.22 ± 0.05 mg gallic acid equivalents/g and 0.25 ± 0.07 to 0.87 ± 0.14 mg rutin equivalents/g. UHPLC-QqQ-MS/MS analysis revealed 12 individual polyphenol compounds in longan. The Fuwan8, Dongliang and FD97 varieties showed the strongest DPPH scavenging activity (IC50 of 1.03 g/mL). The highest ABTS+ scavenging activity was found in the Dongliang. In the enzyme assays, the Fuwan8 and Dongliang varieties demonstrated maximum α-amylase and α-glucosidase inhibition activities, with values of 97.56 and 88.58%, respectively. The principal component analysis indicated that the Rongyu8 and Songfengben cultivars have nearly analogous polyphenol compounds.

中文翻译：

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龙眼的酚含量，抗氧化能力以及α-淀粉酶和α-葡萄糖苷酶的抑制活性。

这项研究的目的是比较长江中上游地区种植的八种龙眼（Dimocarpus longan Lour。）的酚类化合物概况和抗氧化能力。干燥龙眼肉的总多酚含量（TPC）和总黄酮含量（TFC）为1.07±0.05至1.22±0.05 mg没食子酸当量/ g和0.25±0.07至0.87±0.14 mg芦丁当量/ g。UHPLC-QqQ-MS / MS分析显示龙眼中有12种独立的多酚化合物。Fuwan8，Dongliang和FD97品种表现出最强的DPPH清除活性（IC50为1.03 g / mL）。在东凉发现了最高的ABTS +清除活性。在酶分析中，Fuwan8和Dongliang变种表现出最大的α-淀粉酶和α-葡萄糖苷酶抑制活性，分别为97.56和88.58％。