Soldera-Silva Andressa, Seyfried Melina, Campestrini Luciano Henrique, Zawadzki-Baggio Selma Faria, Minho Alessandro Pelegrine, Molento Marcelo Beltrão, Maurer Juliana Bello Baron
Department of Biochemistry and Molecular Biology, Federal University of Paraná, 81531-980, Curitiba, PR, Brazil.
Embrapa Southeast Livestock, 13560-970, São Carlos, SP, Brazil.
Vet Parasitol. 2018 Feb 15;251:34-43. doi: 10.1016/j.vetpar.2017.12.019. Epub 2017 Dec 27.
The aim of this study was to characterize the extracts and fractions of Persea americana Mill. (Avocado) seeds and to determine the composition and the in vitro anthelmintic activity against third-stage larvae (L3) of Haemonchus contortus. The fresh (F) and dried (H) avocado seeds (PA) were subjected to extraction with hot water (W-PAF, W-PAH), ethanol (E-PAF, E-PAH) or methanol 70% (v/v), and partition with solvents of increasing polarity [n-hexane (H-PAF, H-PAH), chloroform (C-PAF, C-PAH), ethyl acetate (Ea-PAF, Ea-PAH), and n-butanol (B-PAF, B-PAH)], yielding a total of 14 extracts/fractions. After considering the yield, water solubility, and the preliminary results of the larval migration test (LMT), the E-PAF, E-PAH, H-PAF, and H-PAH were selected for further experiments. E-PAH presented an efficiency concentration of 50% (EC) of 36 μg/mL on the LMT. E-PAH showed the greatest efficiency when its EC was compared to the other fractions (E-PAF = 147 μg/mL; H-PAF = 801 μg/mL; H-PAH = 77 μg/mL). After that, the E-PAH was chemically characterized, considering its quantitative polyphenolic and flavonoid contents by colorimetric and chromatographic techniques. E-PAH presented 50, 38, and 24 mg/g of dry matter of total phenol, condensed tannins (CT), and flavonoid contents, respectively. Using high performance liquid chromatography (HPLC) analysis, E-PAH had shown to have epicatechin (4.7 μg/mL), rutin (2.8 μg/mL), and chlorogenic acid (1.4 μg/mL) as its main constituents besides quercetin. These isolated compounds were evaluated using the LMT in order to relate the composition to the anthelmintic activity observed for E-PAH. Quercetin (EC = 7.8 μg/mL) and epicatechin (EC = 10 μg/mL) presented a higher efficiency than rutin (EC = 30 μg/mL). Chlorogenic acid was also tested with the LMT but did not present a significant efficiency. According to the results, the phenolic composition of E-PAH and the EC values obtained for the isolated phenols, it can be suggested that, besides the CT content, the presence of epicatechin and rutin contributed to the larvicidal activity of E-PAH. In conclusion, avocado seeds may be used as a source of polyphenols with promising anthelmintic applications.
本研究的目的是对鳄梨（Persea americana Mill.）种子的提取物和馏分进行表征，并确定其成分以及对捻转血矛线虫三期幼虫（L3）的体外驱虫活性。将新鲜（F）和干燥（H）的鳄梨种子（PA）分别用热水（W-PAF、W-PAH）、乙醇（E-PAF、E-PAH）或70%（v/v）甲醇进行提取，并用极性递增的溶剂进行分配[n-己烷（H-PAF、H-PAH）、氯仿（C-PAF、C-PAH）、乙酸乙酯（Ea-PAF、Ea-PAH）和正丁醇（B-PAF、B-PAH）]，共得到14种提取物/馏分。在考虑产率、水溶性和幼虫迁移试验（LMT）的初步结果后，选择E-PAF、E-PAH、H-PAF和H-PAH进行进一步实验。E-PAH在LMT上的半数有效浓度（EC）为36μg/mL。与其他馏分相比，E-PAH的EC值显示出最高的效率（E-PAF = 147μg/mL；H-PAF = 801μg/mL；H-PAH = 77μg/mL）。之后，通过比色法和色谱技术对E-PAH的总多酚和黄酮含量进行定量分析，对其进行化学表征。E-PAH的总酚、缩合单宁（CT）和黄酮含量分别为50、38和24mg/g干物质。使用高效液相色谱（HPLC）分析，除槲皮素外，E-PAH的主要成分还有表儿茶素（4.7μg/mL）、芦丁（2.8μg/mL）和绿原酸（1.4μg/mL）。使用LMT对这些分离出的化合物进行评估，以便将成分与观察到的E-PAH的驱虫活性联系起来。槲皮素（EC = 7.8μg/mL）和表儿茶素（EC = 10μg/mL）的效率高于芦丁（EC = 30μg/mL）。也用LMT对绿原酸进行了测试，但未显示出显著的效率。根据结果，E-PAH的酚类成分以及分离出的酚类化合物的EC值，可以认为，除了CT含量外，表儿茶素和芦丁的存在有助于E-PAH的杀幼虫活性。总之，鳄梨种子可能作为具有潜在驱虫应用前景的多酚来源。
