Archives of Current Research International

Fenugreek (Trigonella foenum-graecum L.) seeds are recognised as a valuable source of bioactive constituents, particularly phenolics, flavonoids and saponins, which collectively contribute to their antioxidant properties. This study evaluated the ultrasound-assisted extraction of bioactive compounds from dried fenugreek seeds using methanol as the extraction solvent. Response Surface Methodology, based on a Central Composite Design, was applied to assess the effects of extraction time, solvent temperature and ultrasonication power on total phenolic content, total flavonoid content, total saponin content and antioxidant activity. The investigated extraction conditions comprised extraction times of 10-50 min, solvent temperatures of 30-50 °C and ultrasonication power levels of 60-100%. Total phenolic content, total flavonoid content and total saponin content ranged from 13.35 to 26.83 mg GAE/g DW, 27.08 to 35.60 mg QE/g DW and 76.50 to 101.25 mg DE/g DW, respectively. Antioxidant activity, expressed as IC₅₀, ranged from 265.80 to 298.50 μg/mL. The fitted quadratic models were significant, with coefficients of determination ranging from 0.9419 to 0.9916, indicating that the selected process variables adequately explained the extraction responses. Numerical optimisation identified an extraction time of 33.08 min, a solvent temperature of 38.78 °C and an ultrasonication power of 86.17% as the optimum conditions, with an overall desirability value of 0.748. Under these conditions, the predicted responses were 26.74 mg GAE/g DW for total phenolic content, 35.88 mg QE/g DW for total flavonoid content, 101.25 mg DE/g DW for total saponin content and 265.80 μg/mL for IC₅₀. Overall, the findings indicate that ultrasound-assisted extraction can enhance the recovery of methanol-soluble bioactive compounds from dried fenugreek seeds under optimised processing conditions and may provide a useful basis for further laboratory-scale extraction studies.