2.1. Extraction of active components from common bean seed
The locally obtained common bean (P. vulgaris) dry seed was ground to a fine powder by using a laboratory mill and sieved through 0.4 mm sieve. The fraction with particle size less than 0.4 mm was used in experiments. Ten grams of seed powder was suspended in 1 L of NaCl water solution (0.5 mol/L). The suspension was stirred using a magnetic stirrer for 10 min to accomplish extraction and then filtered through a rugged filter paper (Macherey-Nagel, MN 651/120) to obtain filtrate – crude extract of active components.