Martín-García Beatriz, Aznar-Ramos María José, Verardo Vito, Gómez-Caravaca Ana María
Department of Analytical Chemistry, Faculty of Sciences, University of Granada, Avd. Fuentenueva s/n, 18071 Granada, Spain.
Department of Nutrition and Food Science, University of Granada, Campus of Cartuja, 18071 Granada, Spain.
Plants (Basel). 2022 Aug 4;11(15):2034. doi: 10.3390/plants11152034.
The leaves of Mill (cherimoya) are a potential source of phenolic compounds that have been shown to have beneficial properties. Therefore, this study focuses on establishing an ultrasonic-assisted extraction of phenolic compounds in cherimoya leaves using a sonotrode. For that purpose, a Box-Behnken design based on a response surface methodology (RSM) was used to optimize factors, such as amplitude, extraction time and solvent composition to obtain the maximum content of phenolic compounds by HPLC-MS and the maximum in-vitro antioxidant activity by DPPH, ABTS and FRAP assays in 'Fino de Jete' cherimoya leaves. The optimal conditions were 70% amplitude, 10 min and 40:60 ethanol/water (EtOH/HO) (/). The results obtained under these optimum conditions by using a sonotrode were compared with those from an ultrasonic bath; briefly, recovery of phenolic compounds by sonotrode was 2.3 times higher than a bath. Therefore, these optimal conditions were applied to different varieties 'Campas', 'Fino de Jete' and 'Negrito Joven' harvested in the Tropical Coast of Granada (Spain). A total of 39 phenolic compounds were determined in these cherimoya leaf extracts, 24 phenolic compounds by HPLC-MS and 15 proanthocianidins by HPLC-FLD. 5-p-coumaroylquinic acid, lathyroside-7-O-α-l-rhamnopyranoside and quercetin hexose acetate were first identified in cherimoya leaves. The most concentrated phenolic compounds were the flavonoids, such as rutin and quercetin hexoside and proanthocyanidins including monomers. Almost no significant differences in the phenolic content in these cultivars were found (11-13 mg/g d.w. for phenolic compounds and 11-20 mg/g d.w. for proanthocyanidins). In addition, sonotrode ultrasonic-assisted extraction has been shown to be an efficient extraction technique in the phenolic recovery from cherimoya leaves that could be implemented on an industrial scale.
番荔枝（释迦果）的叶子是酚类化合物的潜在来源，这些酚类化合物已被证明具有有益特性。因此，本研究聚焦于使用超声探头建立超声辅助提取番荔枝叶中酚类化合物的方法。为此，基于响应面法（RSM）的Box-Behnken设计用于优化诸如振幅、提取时间和溶剂组成等因素，以通过高效液相色谱-质谱联用（HPLC-MS）获得酚类化合物的最大含量，并通过二苯基苦味酰基自由基（DPPH）、2,2'-联氮-双-3-乙基苯并噻唑啉-6-磺酸（ABTS）和铁离子还原抗氧化能力（FRAP）测定法获得“菲诺德赫特”番荔枝叶的最大体外抗氧化活性。最佳条件为70%振幅、10分钟和40:60的乙醇/水（EtOH/H₂O）（v/v）。将使用超声探头在这些最佳条件下获得的结果与超声浴的结果进行比较；简而言之，超声探头对酚类化合物的回收率比超声浴高2.3倍。因此，将这些最佳条件应用于在西班牙格拉纳达热带海岸收获的不同品种“坎帕斯”、“菲诺德赫特”和“小黑仔”。在这些番荔枝叶提取物中总共测定了39种酚类化合物，通过HPLC-MS测定了24种酚类化合物，通过HPLC-荧光检测法（HPLC-FLD）测定了15种原花青素。5-对香豆酰奎尼酸、山黧豆苷-7-O-α-L-鼠李吡喃糖苷和槲皮素己糖乙酸酯首次在番荔枝叶中被鉴定出来。最浓缩的酚类化合物是黄酮类化合物，如芦丁和槲皮素己糖苷以及包括单体在内的原花青素。在这些品种中，酚类含量几乎没有显著差异（酚类化合物为11 - 13毫克/克干重，原花青素为11 - 20毫克/克干重）。此外，超声探头超声辅助提取已被证明是从番荔枝叶中回收酚类的一种有效提取技术，可在工业规模上实施。
