[Leukocyanidines and collagenases: in vitro enzyme inhibition activity]

The matrix metalloproteinases (MMPs) play a key role in the extracellular matrix turnover. This protein family has been involved in some ocular pathologies such as glaucoma, diabetic retinopathy, macular degeneration, vitreous degeneration and corneal stroma ulceration cleaving all the matrix components. In the present study we evaluated the action of leucocyanidin from Vitis vinifera seeds as non toxic inhibitor of these proteinases.

To this purpose we used a fluorimetric method to evaluate the effect of this substance on the collagenase activity. We evaluated "in vitro" the inhibitory potency of the tested drug on type III collagenase activity, and the recover of the metalloprotease activity upon removal by dialysis of the inhibitor.

The leucocyanidines extract (minimum procyanidines value of 95.0) resulted to be a good collagenase activity inhibitor showing an inhibition constant value, Ki, of 82 microM, evident index of affinity between the extract and the enzyme. Furthermore, the dialysis experiments demonstrated that the inhibitory effect persisted 24 h later, probably because the extract forms a stable complex with the enzyme.

These results should be related to the pharmacokinetic profile of leucoanthocyanins, a family of natural polyphenols belonging to the class of bioflavonoids of grape seds extract (Vitis vinifera L.).