Maximum Phenylalanine Ammonium Lyase (PAL) Enzyme activity at Mid Stage of Growth Imparts Highest Hypoglycemic Property to Fenugreek

PAL catalyzes the first step in the biosynthesis of phenylpropanoids, which are further modified into a wide variety of phenolic compounds. In the current study, we estimated the change in PAL enzyme activity and total phenol content in six cultivars of fenugreek (ML1-ML6) seeds and vegetative green leafy parts of their respective plants taken at early, mid and late stages of growth. The results obtained were correlated with their respective hypoglycemic activities. Our study demonstrated that, at the mid stage of growth all the cultivars showed maximum PAL activity with simultaneous increase in phenol production and hypoglycemic activities. The results of this study taken together suggest that all the fenugreek cultivars possess good hypoglycemic activity that is directly related to increase in total phenol content and PAL activity. Among six selected cultivars, ML-2 cultivar in addition to possess maximum hypoglycemic activity in terms of inhibiting α-amylase (72.53%) and α-glucosidase (52%) activities also showed maximum PAL enzyme activity (0.01008 μM cinnamic acid/mg protein/min) as well as total phenol production (560 mg/100g fresh weight) at mid stage of growth. A highly significant correlation was found between PAL activity and total phenols (r=0.759) which were significantly correlated with α-amylase inhibitory activity (r=0.439, r=’0.690 respectively) as well as with α glucosidase inhibitory activity (r=0.507, r=0.552 respectively). It was observed that extracts from such cultivars especially that of ML2 cultivar taken at mid stage of growth when incorporated into diet could act as a potential chemopreventive functional food for better management of hyperglycemia.