Unlocking Agave bracteosa Saponins: Optimized green extraction through Box-Behnken design

Ultrasound-assisted extraction has emerged as an eco-friendly and efficient alternative for the recovery of bioactive compounds from plant matrices. The present study aimed to optimize the UAE conditions for obtaining saponin-enriched extracts from Agave bracteosa leaves. To this end, a Box-Behnken design coupled with response surface methodology was employed to evaluate the influence of the following factors on saponin yield: ethanol concentration, extraction temperature, sample-to-solvent ratio, ultrasound cycle, and amplitude. The optimal conditions were as follows: 71 % ethanol in water, 34 °C, a sample-to-solvent ratio of 0.02 g/20 mL, a 0.3 s on/0.7 s off cycle, 20 % amplitude, and 5 min. The extracts were analyzed using UPLC-QTOF/MS^E, leading to the identification of saponins recently reported for Agave bracteosa. The optimized method demonstrated high repeatability and applicability across different Agave species (A. americana and A. lophanta). An extraction efficiency (%EE) of 2739 was achieved compared with preliminary UAE extractions. This study highlights the potential of ultrasound-assisted extraction as a sustainable and effective technique for saponin extraction with important advantages such as reduced energy consumption and processing time.