Effect of extraction solvents on antioxidant and antimicrobial properties of fenugreek seeds (Trigonella foenum-graecum L.)
The present study was aimed to investigate the efficacy of fenugreek seeds as a potential natural source of antioxidants and antimicrobials. Fenugreek seed (FS) extracts were prepared using ethanol (75%), methanol (75%) and water as extraction solvents. Ethanol (E-FSP), methanol (M-FSP), water (W-FSP) and hot water (HW-FSP) extracts were obtained from ground FS, whilst water extract (W-GeFS) was obtained from germinated FS. The results revealed that all extracts of the ground FS exhibited antioxidant and antimicrobial activities and the extractability of bioactive compounds in the presence of water was higher in germinated seeds (W-GeFS). Highest phenolic (156.3 mg GAE/ g) and flavonoid (38.5 mg CE/ g) contents were found in W-GeFS. It also showed the strongest DPPH radical-scavenging activity of 68 % inhibition at a lower concentration (0.06 mg/ ml). In addition, highest vitamin C equivalent antioxidant capacity (143.28 mg vitamin C/ g) with an IC 50 value of 42.1 µg/ ml were found in W-GeFS. Based on disc diffusion method, W-GeFS exhibited highest antimicrobial activity against all tested bacterial pathogens (Bacillus subtilis, Staphylococcus aureus, and Escherichia coli). Thus, it can be concluded from the results that W-GeFS extract from germinating fenugreek seeds (W-GeFS) has the potential to be used as a natural source of bioactive compounds with varied applications in food industry especially, for active film packaging purposes to prolong the shelf-life of food products.