Effects of escins Ia, Ib, IIa, and IIb from horse chestnut, the seeds of Aesculus hippocastanum L., on acute inflammation in animals.

We investigated the effects of escins Ia, Ib, and IIb isolated from horse chestnut, the seeds of Aesculus hippocastanum L., and desacylescins I and II obtained by alkaline hydrolysis of escins on acute inflammation in animals (p.o.). Escins Ia, Ib, IIa, and IIb (50-200 mg/kg) inhibited the increase of vascular permeability induced by both acetic acid in mice and histamine in rats. Escins Ib, IIa, and IIb (50-200 mg/kg) also inhibited that induced by serotonin in rats, but escin Ia didn't. Escins Ia, Ib, IIa, and IIb (200 mg/kg) inhibited the hind paw edema induced by carrageenin at the first phase in rats. Escin Ia (200 mg/kg) and escins Ib, IIa, and IIb (50-200 mg/kg) inhibited the scratching behavior induced by compound 48/80 in mice, but escin Ia was weakest. Desacylescins I and II (200 mg/kg) showed no effect. With regard to the relationship between their chemical structures and activities, the acyl groups in escins were essential. Escins Ib, IIa, and IIb with either the 21-angeloyl group or the 2'-O-xylopyranosyl moiety showed more potent activities than escin Ia which had both the 21-tigloyl group and the 2'-O-glucopyranosyl moiety.