Investigating the In Vitro Anti-Obesity Activity of the Ultrasonic-Assisted Extraction Process of Alkaloid- Rich Extract from <i>Mansoa alliacea</i> Flowers Using Response Surface Methodology

<i>Mansoa alliacea</i> is a member of the Bignoniaceae family and a common medicinal herb found in Asian nations. However, scientific studies conducted on this species are still limited. Therefore, this study was conducted to optimize the extraction process of <i>M. alliacea</i> flowers and evaluate the therapeutic activity of the optimized alkaloid-rich extract. The optimization process was developed using response surface methodology with Box–Behnken model, assisted by ultrasound. The optimal extraction conditions were: temperature, 79°C; ultrasound time, 16 minutes; ethanol concentration, 80% (v/v); and raw material–solvent ratio 1:30 (w/v). The stated conditions yielded the total alkaloid content of 196.58 mg of atropine equivalent (AE)/g extract. This prediction model was determined to be highly reliable. The optimized extract had excellent anti-obesity activity, with IC<sub>50</sub> values observed in various assays as follows: anti-cholesterol activity (IC<sub>50</sub>= 18.64 ± 0.32 µg/mL), pancreatic lipase inhibition (IC<sub>50</sub>= 12.24 ± 0.05 µg/ mL), and inhibition of carbohydrate metabolism enzymes including α-amylase (IC<sub>50</sub> = 13.49 ± 0.23 µg/mL) and α-glucosidase (IC<sub>50</sub> = 68.56 ± 1.99 µg/mL). Additionally, the extract showed antioxidant activity with IC₅₀ values ranging from 11.87 ± 0.23 µg/mL to 30.43 ± 2.13 µg/mL, depending on the assay used, and exhibited antibacterial activity against the Gram-negative bacterium <i>Enterobacter cloacae</i>, with inhibition zone diameters ranging from 21.90 ± 0.66 mm to 46.60 ± 0.53 mm. These bioactivities were related to the alkaloid content of the optimal extract. These findings indicated that <i>M. alliacea</i> flower could be used as a potential pharmaceutical product.