AbstractTriterpene and steroid saponins and sapogenins of medicinal plants (Aesculus hippocastanumL.,Hedera helixL.,Ruscus aculeatusL.) are claimed to be effective for the treatment/prevention of venous insufficiency. In this work we evaluated the inhibitory effects of these plant constituents on the activity of elastase and hyaluronidase, the enzyme systems involved in the turnover of the main components of the perivascular amorphous substance.The results evidence that forHedera helixL., the sapogenins only non‐competitively inhibit hyaluronidase activity in a dose‐dependent fashion, showing comparable IC50values (hederagenin IC50= 280.4 μM; oleanolic acid IC50= 300.2 μM); both the saponins hederacoside C and α‐hederin are very weak inhibitors.The same behaviour is observed for serine protease porcine pancreatic elastase: the glycosides are devoid of inhibitory action, while genins are potent competitive inhibitors (oleanolic acid IC50= 5.1 μM; hederagenin IC50= 40.6 μM). Constituents fromAesculus hippocastanumL. show inhibitory effects only on hyaluronidase, and this activity is mainly linked to the saponin escin (IC50= 149.9 μM), less to its genin escinol (IC50= 1.65 μM).By contrast, ruscogenins fromRuscus aculeatusL., ineffective on hyaluronidase activity, exhibit remarkable anti‐elastase activity (IC50= 119.9 μM; competitive inhibition). The mechanism of elastase inhibition by triterpene and steroid aglycones, with a nitroanilide derivative as substrat