Martínez-Castro Robinson, Flórez-Santiago Jiress, Valle-Molinares Roger, Cabrera-Barraza Julián, Espitia-Almeida Fabián
Faculty of Engineering, Chemical Engineering Program, Universidad del Atlántico, Puerto Colombia, 081001, Colombia.
Faculty of Basic Sciences, Chemistry Program, Universidad del Atlántico, Puerto Colombia, 081001, Colombia.
Heliyon. 2024 May 18;10(10):e31504. doi: 10.1016/j.heliyon.2024.e31504. eCollection 2024 May 30.
The neem tree ( A. Juss) is grown mainly for shade, fuel, and numerous non-timber forest products using its leaves, fruit, and bark. It produces an essential oil that is used as a source for obtaining bioinsecticides, with a broad spectrum of action in agricultural production. Its bioinsecticidal activity is due to the presence of triterpenes, such as azadirachtin, a product in continued growth of the global biopesticide market. Optimal conditions for neem oil extraction using response surface methodology (RSM) and microwave-assisted extraction (MAE) methods have been defined. However, the extraction conditions for these methods tend to consume high volumes of organic solvent and long extraction times. The aim of the present study is to determine the optimal conditions for the extraction of azadirachtin from neem seeds in a hydroalcoholic medium using MAE and RSM with a Box-Behnken design (BBD). A BBD was applied to evaluate the effects of the factors, magnetron voltage (X), extraction time (X), and pH of the extraction medium (X), on the yield of the azadirachtin extraction process. The effect of each variable on the extraction yield was studied independently, considering the pure coefficients (linear and quadratic) on the three levels that were studied in the experiments. Moreover, the study experiments were conducted in triplicate, data were presented as mean and standard deviation, homogeneity of variances was estimated using Levene's test, and a two-way ANOVA with Tukey's post hoc analysis was performed to identify the experimental conditions that allowed us to find the highest extraction yield and to analyze whether the response surface model adequately described our data. The most significant effects of the model correspond to quadratic and interaction effects (p < 0.0001); the quadratic terms voltage (X), extraction time (X), and pH (X); and the interaction effects between voltage-pH (XX) and time-pH (XX), which had a significant influence on the model. Moreover, a canonical analysis was performed. The optimal conditions were as follows: 69.22 V, 6.89 min, and a pH value of 4.35, coinciding with the zones shown in the contour plots. Furthermore, the response obtained at the optimal conditions was 37.5 μg of azadirachtin per gram of pretreated seed.
印楝树（A. Juss）主要因其树荫、燃料以及利用其树叶、果实和树皮生产的众多非木材林产品而种植。它能产出一种精油，该精油用作获取生物杀虫剂的来源，在农业生产中具有广泛的作用谱。其生物杀虫活性归因于三萜类化合物的存在，如印楝素，这是全球生物农药市场持续增长的一种产品。已经确定了使用响应面法（RSM）和微波辅助萃取（MAE）方法提取印楝油的最佳条件。然而，这些方法的提取条件往往消耗大量有机溶剂且提取时间长。本研究的目的是使用MAE和带有Box-Behnken设计（BBD）的RSM确定在水醇介质中从印楝种子中提取印楝素的最佳条件。应用BBD来评估因素磁控管电压（X₁）、提取时间（X₂）和提取介质的pH值（X₃）对印楝素提取过程产率的影响。考虑实验中研究的三个水平上的纯系数（线性和二次），独立研究每个变量对提取产率的影响。此外，研究实验重复进行三次，数据以平均值和标准差表示，使用Levene检验估计方差齐性，并进行带有Tukey事后分析的双向方差分析，以确定使我们能够找到最高提取产率的实验条件，并分析响应面模型是否充分描述了我们的数据。模型中最显著的影响对应于二次效应和交互效应（p < 0.0001）；二次项电压（X₁²）、提取时间（X₂²）和pH值（X₃²）；以及电压-pH（X₁X₃）和时间-pH（X₂X₃）之间的交互效应，它们对模型有显著影响。此外，进行了规范分析。最佳条件如下：69.22 V、6.89分钟和pH值4.35，与等高线图中所示区域一致。此外，在最佳条件下获得的响应是每克预处理种子含37.5μg印楝素。
