Effect of a flavonoid preparation (S 5682) on experimental capillary permeability increase in rat paw and rabbit skin

S 5682 is constituted by a flavonoid mixture of 90% diosmin and 10% hesperidin. Its action has been studied in vivo on microcirculation by measuring experimental alterations of capillary permeability and of venous pressure. Rats were pretreated by IV injection of 25 mg S 5682/kg, one hour before being submitted to a transitory compression of the posterior paw, resulting in reversible oedema that was estimated by plethysmography. The swelling of the paw in pretreated rats was lower than in controls (p less than 0.02), indicating a smaller increase of capillary permeability in rats treated with S 5682. A direct action on capillary permeability has been examined by measuring accumulation of IV injected Evans blue at the site of injection of zymosan, this accumulation was lower in pretreated rats than in controls (p less than 0.05). Similarly, in CFY rats, the pressure required to evoke capillary fragilisation was higher in S 5682 pretreated rats. Evans blue extravasation was also studied in the rabbit in which skin was irritated by topical application of chloroform of by gamma rays. Subcutaneous accumulation of Evans blue was lower in animals pretreated either IV or by oral route than in controls (p less than 0.05). S 5682 has a complex effect on microcirculation as indicated by a smaller increase in femoral venous pressure after ligation of homolateral iliac vein. The above experimental results indicate that S 5682 is acting at the venous side of the microcirculation.