番石榴4个品种叶和幼果的生物活性和酚类成分研究

Biological Activities and Phenolic Constituents in Extracts from Leaves and Young Fruits of Four Guava Cultivars

摘要:

为提高番石榴（Psidium guajava）副产物的综合利用率，测定了‘珍珠’、‘水蜜’、‘红宝石’和‘西瓜’4个品种叶和幼果提取物中的酚类与黄酮含量，并分析了其与清除DPPH·、ABTS⁺、HO·自由基能力和α-葡萄糖苷酶抑制活性的相关性，并用超高效液相色谱-串联质谱法（UPLC-MS/MS）分析了提取物的酚类成分。结果表明，4个番石榴品种叶的酚类和黄酮含量、清除自由基能力、α-葡萄糖苷酶抑制活性均显著高于幼果，‘珍珠’叶的酚类含量最高，生物活性最强。酚类、黄酮含量与清除自由基能力呈极显著正相关（P<0.01），与α-葡萄糖苷酶抑制活性呈显著正相关（P<0.05）。UPLC-MS/MS鉴定结果表明，4个品种叶酚类含量较高的均为槲皮素-3-O-葡萄糖苷、金丝桃苷、鞣花酸和杨梅苷，除鞣花酸外大部分存在于叶的酚类成分也存在于幼果中，且含量显著高于幼果。因此，4个品种中，‘珍珠’叶是开发天然抗氧化剂和α-葡萄糖苷酶抑制剂的优良资源。

Abstract:

In order to improve the comprehensive utilization rate of the by-products of guava (Psidium guajava), the biological activities and phenolic constituents of extracts from 4 cultivars (‘Zhenzhu’, ‘Shuimi’, ‘Hongbaoshi’, ‘Xigua’) of guava were studied. The contents of total phenols and flavonoids were determined, then the correlations between the contents of phenols and flavonoids with biological activities were analyzed, including the scavenging abilities on DPPH·, ABTS⁺, HO· free radicals, and the α-glucosidase inhibitory activity. Furthermore, the phenolic constituents of extracts were identified by ultra-high performance liquid chromatography and the triple-quadrupole tandem mass spectrometry (UPLC-MS/MS). The results showed that the contents of total phenols and flavonoids, the free radicals scavenging abilities and α-glucosidase inhibitory activity in leaves of 4 cultivars were significantly higher than those in young fruits, ‘Zhenzhu’ leaf had the highest content of total phenols as well as the most potent free radicals scavenging abilities and α-glucosidase inhibitory activity. Correlation analysis revealed that the contents of phenols and flavonoids were significantly positively correlated with the scavenging abilities towards DPPH·, ABTS⁺, HO· free radicals (P<0.01), as well as the α-glucosidase inhibitory activity (P<0.05). UPLC-MS/MS analysis showed that the contents of quercetin-3-O-glucoside, hyperoside, ellagic acid and myricitrin in leaves of 4 cultivars were high, and most of the constituents found in leaves except ellagic acid also existed in the young fruits, and the contents in leaves were higher than those in young fruits. Therefore, ‘Zhenzhu’ guava leaf could be a good resource for developing natural antioxidant and α-glucosidase inhibitor among 4 cultivars.