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Potent and specific inhibitors of hyaluronidases, a group of enzymes preferentially catalysing the hydrolysis of hyaluronic acid, are not known so far. Such compounds could be useful as pharmacological tools for studying the physiological and pathophysiological role of both hyaluronan and hyaluronidases. The effects of sulphated and non-sulphated structurally different oligosaccharides on bovine testicular hyaluronidase, hyaluronidase from bee venom and hyaluronate lyase from Streptococcus agalactiae (hylB (4755)) were studied with the Morgan-Elson reaction. Several active compounds were identified within a series of sulphated beta-(1,4)-galacto-oligosaccharides. The determined IC (50) values of these sulphated oligosaccharides ranged from 4 microM to 630 microM for all hyaluronan-degrading enzymes. Sulphated oligosaccharides like verbascose, planteose and neomycin showed comparable inhibition on all hyaluronidases, thereby possessing 100 - 500 times the activity of the widely accepted hyaluronidase inhibitor apigenin.

Angiogenesis is a strictly controlled process in the healthy, adult human body. It is regulated by a variety of endogenous angiogenic and angiostatic factors. It is only switched on, e.g., during wound healing. Pathological angiogenesis occurs, for example, in cancer, chronic inflammation, or atherosclerosis. Angiogenesis inhibitors are able to interfere with various steps of angiogenesis, like basement destruction of blood vessels, proliferation and migration of endothelial cells, or the lumen formation. Among the known angiogenesis inhibitors compounds derived from natural sources, like flavonoids, sulphated carbohydrates, or triterpenoids are playing a prominent role.

The ethanolic extract of Ilex aquifolium L. (Aquifoliaceae) concentration-dependently inhibited leukotriene B4 biosynthesis in isolated bovine PMNL with an IC50 value of about 60 micrograms/ml, whereas the effect on epidermal 12(S)-HETE biosynthesis was much less pronounced. The extract also inhibited the non-enzymatic, peroxyl radical-stimulated lipid peroxidation in model membranes and was further a scavenger of the iron-dependent generation of hydroxyl radicals from hydrogen peroxide as determined by protection against deoxyribose degradation. While inhibition of leukotriene biosynthesis was not mediated by its known phenolic constituents such as hyperoside, rutoside, and chlorogenic acid, these compounds were responsible for the inhibitory effects of I. aquifolium against non-enzymatic lipid peroxidation and deoxyribose degradation.

Application of [ (14)C]-progesterone to the leaves of NERIUM OLEANDER L. (Apocynaceae) resulted in the formation of [ (14)C]-digitoxigenin and [ (14)C]-oleandrigenin glycosides; the labelled aglycones were obtained after hydrolysis from the cardenolide extract. Both radioactive cardenolide aglycones were further transformed by the leaves of NERIUM OLEANDER L. to the corresponding 3- O-beta-glucosides digitoxigenin glucoside and oleandrigenin glucoside. It could be shown that both cardenolide glucosides are genuine constituents of the cardenolide fraction of NERIUM OLEANDER L. leaves. The structures of these newly identified compounds were verified by (1)H-NMR and FAB (+) mass spectroscopy and by enzymatic cleavage of the glycosidic bond with a beta-glucosidase from HELIX POMATIA.