山茶各部位黄酮提取工艺优化及提取物成分分析

熊诗蓓; 邓闯; 范益飞; 杨灵光

doi:10.13386/j.issn1002-0306.2023070010

山茶各部位黄酮提取工艺优化及提取物成分分析

Extraction Optimization of Flavonoid Compounds from Various Parts of Camellia japonica and Constituent Analysis of the Extracts

摘要

摘要: 目的：优化山茶花瓣、叶和花蕊三部位的黄酮提取量，比较抗氧化活性并分析其化学成分。方法：以总黄酮提取量为评价指标，通过单因素实验和正交试验优化超声波辅助酶解法黄酮提取工艺。采用DPPH、ABTS⁺自由基清除实验和还原力实验评价优化后总黄酮提取物的抗氧化能力。通过超高效液相色谱-四极杆飞行时间质谱联用技术（UPLC-QTOF-MS/MS）分析各部位的化学成分。结果：在最优提取工艺下，山茶各部位总黄酮提取量依次为叶（63.14 RE mg/g）>花蕊（58.77 RE mg/g）>花瓣（20.26 RE mg/g）。抗氧化活性测定结果表明，花瓣、叶、花蕊中黄酮清除DPPH自由基的IC₅₀值分别为7.28、2.51、1.15 mg/mL，清除ABTS⁺自由基的IC₅₀值分别为2.85、0.95、0.59 mg/mL，还原力分别为63.25、214.11、475.90 Trolox mg/g，其抗氧化强弱顺序为：花蕊>叶>花瓣。通过UPLC-QTOF-MS/MS从花瓣、叶、花蕊三部位共鉴定出29种化合物，且B型原花青素二聚体、表儿茶素、槲皮素-3-O-半乳糖苷等黄酮单体化合物在三个部位中的分布规律与总黄酮提取量一致。结论：超声波辅助酶法能够有效提高黄酮类化合物的提取量，且山茶的叶和花蕊部位具有较高黄酮含量及抗氧化活性。

Abstract: Objective: To optimize the extraction amount of flavonoid from petals, leaves, stamens and pistils of Camellia japonica, respectively, and compare the antioxidant activity and analyze the chemical constituents of the extracts. Method: The total flavonoids extraction amount was used as evaluation index, and single-factor experiments and orthogonal tests were used to optimize the ultrasonic-assisted enzymatic extraction process of flavonoids. The antioxidant capacity of optimized flavonoids extract was evaluated by DPPH and ABTS⁺ free radical scavenging and reducing power experiment. And the chemical constituents of extracts from each part were qualitatively analyzed by ultra-performance-liquid-chromatography quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS/MS). Results: In the optimum extraction condition, the total flavonoids extraction amount form each part of Camellia japonica were in the order as follows: Leaves (63.14 RE mg/g)>stamens and pistils (58.77 RE mg/g)>petals (20.26 RE mg/g). Meanwhile, the results of antioxidant activity determination showed that the IC₅₀ values of DPPH and ABTS⁺ free radical scavenging assay of extracts from petals, leaves, stamens and pistils were 7.28, 2.51, 1.15 mg/mL, and 2.85, 0.95, 0.59 mg/mL, respectively. And the reducing power value of extracts from petals, leaves, stamens and pistils were 63.25, 214.11, 475.90 Trolox mg/g. Therefore, the antioxidant activities of the extracts were in the order of stamens and pistils>leaves>petals. At last, a total of 29 flavonoid-related compounds were identified from the three parts by UPLC-QTOF-MS/MS, and the distribution pattern of B-type procyanidin dimer, epicatechin, quercetin-3-O-galactoside and some other flavonoid compounds in the three parts was consistent with that of total flavonoids extraction amount. Conclusion: Ultrasound-assisted enzymatic extraction effectively improved the extraction amount of flavonoids, and the leaves and stamens and pistils parts of Camellia japonica possessed higher flavonoid contents and stronger antioxidant activity.