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Optimization of Ultrasound-Assisted Extraction of (−)-Stepholidine from Onychopetalum amazonicum Leaves Using Response Surface Methodology

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide (−)-Stepholidine, a naturally occurring alkaloid found in the leaves of Onychopetalum amazonicum (Annonaceae), has shown significant pharmacological potential and serves as an important precursor in the synthesis of bioactive compounds. Currently, ultrasound-assisted extraction (UAE), combined with optimization through response surface methodology (RSM), has emerged as a promising strategy to enhance the efficiency of extraction processes. This study aimed to develop an efficient method for extracting (−)-stepholidine from the leaves of O. amazonicum . Powdered leaves were extracted using methanol-based systems assisted by ultrasound, following a central composite rotatable design (CCRD) with three factors: plant-to-solvent ratio (X 1 ), methanol concentration (X 2 ), and extraction time (X 3 ). The samples were quantified by NMR using the PULCON method. The model was validated by ANOVA, and the optimal conditions were determined using RSM. The factors X 2 2 (methanol percentage), X 3 (extraction time), and the interaction X 1 ·X 3 (plant-to-solvent ratio × extraction time) significantly influenced (−)-stepholidine concentration ( p < 0.05). The model showed a good fit (R 2 = 0.728) and was statistically significant ( p = 0.0005). The optimal conditions identified were as follows: a plant-to-solvent ratio of 1:10, 100% methanol, and 20 min of extraction. Experimental validation yielded an average (−)-stepholidine concentration of 82.8 ± 1.3 mg per g of extract, close to the predicted value of 81.2 mg/g. This study demonstrates that optimizing extraction parameters, such as the plant-to-solvent ratio, methanol percentage, and extraction time, is crucial for maximizing (−)-stepholidine recovery. These findings also support the potential of UAE combined with qNMR as a reliable and reproducible approach for the extraction and quantification of bioactive compounds from plant matrices.

Source: ACS Omega

DOI: 10.1021/acsomega.5c06822