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

Mansoa alliacea 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 M. alliacea 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 IC₅₀ values observed in various assays as follows: anti-cholesterol activity (IC₅₀= 18.64 ± 0.32 µg/mL), pancreatic lipase inhibition (IC₅₀= 12.24 ± 0.05 µg/ mL), and inhibition of carbohydrate metabolism enzymes including α-amylase (IC₅₀ = 13.49 ± 0.23 µg/mL) and α-glucosidase (IC₅₀ = 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 Enterobacter cloacae, 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 M. alliacea flower could be used as a potential pharmaceutical product.