Stimulation of the phenylpropanoid pathway and antioxidant capacities by biotic and abiotic elicitation strategies in common bean (Phaseolus vulgaris) sprouts

This study evaluated the impact of different concentrations of glutamic acid (1, 3, 5 and 7 mM) and sodium chloride (NaCl- 100, 200, 300 and 400 mM) elicitations on the biosynthesis of phenolic compounds and their antioxidant properties in common bean sprouts. Results showed that high glutamic acid concentrations (5 and 7 mM) elicited maximum levels of stress markers (H2O2, catalase and peroxidase), phenylpropanoid triggering enzymes (phenylalanine ammonia-lyase and tyrosine ammonia-lyase), and subsequent elevation of phenolic compounds. Although stress markers were elevated, it recorded no negative influence on the sprouting potential of common beans. Also, maximum antioxidant capacities were observed with phenolic compounds extract elicited with 5 mM glutamic acid at 96 h of sprouting, over their NaCl and control counterparts. Multiple quadratic regression studies led to the conclusion that, for optimum biosynthesis of phenolic compounds, synergistic activities of phenylalanine ammonia-lyase and tyrosine ammonia-lyase are required rather than in their isolated catalytic activities.