[Flavonoids extracted from Ribes nigrum L. and Alchemilla vulgaris L.: 1. In vitro inhibitory activities on elastase, trypsin and chymotrypsin. 2. Angioprotective activities compared in vivo].

In vitro experiments were conducted on the inhibitory properties of extracts from Ribes nigrum L. and Alchemilla vulgaris L. (fractions A1 + A2, A1, A2) on activity of the proteolytic enzymes elastase, trypsin and alpha-chymotrypsin. Extracts from Ribes Nigrum L. and Alchemilla Vulgaris L. (Fraction A1) inhibited 50% of the activity of porcine pancreas elastase at concentrations of 0.56 mg/ml and 0.16 mg/ml, respectively, against a synthetic substrate. Inhibition was less effective on activity of trypsin and alpha-chymotrypsin. Marked in vivo angioprotective properties were shown by the compounds studied, except Fraction A2 of Alchemilla vulgaris L. which had no significant activity. The results suggest a possible role by these inhibitors in the protection of conjunctive and elastic tissues adversely affected by proteolytic enzymes. An additional advantage is their lack of toxicity.