Fig. 1. (A) Normal control group. Photomicrograph of the haematoxylin and eosin stained section of rat colon showed intact epithelial surface; ×100. (B) Acetic acid-treated animals, the colonic mucosa showed massive necrotic destruction of epithelium, submucosal oedema, haemorrhages and inflammatory cellular infiltration; ×100. (C) Sulphasalazine-treated group. (C, D and F) Ginkgo biloba-treated groups, treatment with Ginkgo biloba showed a dose-dependent protective effect against acetic acid-induced damage; small doses of Ginkgo biloba (30 and 60 mg kg⁻¹) produced mild and moderate protection (D and E, respectively) while complete protection (F) was observed with the highest dose of Ginkgo biloba (120 mg kg⁻¹); ×100. Drugs were given orally once daily for 2 days before induction of colitis and continued for 5 consecutive days after induction of colitis.

Fig. 2. Effects of different doses of Ginkgo biloba (30, 60 and 120 mg kg⁻¹) on colonic myeloperoxidase (MPO) levels in acetic acid-induced colitis in rats. Results are expressed as mean ± S.E.M. of eight observations. The vehicles or drugs were administered orally once daily for 2 days before induction of colitis and continued for 5 consecutive days after induction of colitis. ^*P < 0.001 as compared to the saline control group. ^#P < 0.001 as compared to the acetic acid group.

Fig. 3. Effects of different doses of Ginkgo biloba (30, 60 and 120 mg kg⁻¹) on colonic interleukin-1β (IL-1β) levels in acetic acid-induced colitis in rats. Results are expressed as mean ± S.E.M. of eight observations. The vehicle or drugs were administered orally once daily for 2 days before induction of colitis and for 5 consecutive days after induction of colitis. ^*P < 0.001 as compared to the saline control group. ^#P < 0.001 as compared to the acetic acid group.

Fig. 4. Effects of different doses of Ginkgo biloba (30, 60 and 120 mg kg⁻¹) on colonic tumor necrosis factor alpha levels (TNF-α) in acetic acid-induced colitis in rats. Results are expressed as mean ± S.E.M. of eight observations. The vehicle or drugs were administered orally once daily for 2 days before induction of colitis and for 5 consecutive days after induction of colitis. ^*P < 0.001 as compared to the saline control group. ^#P < 0.001 as compared to the acetic acid group.

Fig. 5. Effects of different doses of Ginkgo biloba (30, 60 and 120 mg kg⁻¹) on colonic reduced glutathione (GSH) content in acetic acid-induced colitis in rats. Results are expressed as mean ± S.E.M. of eight observations. The vehicle or drugs were administered orally once daily for 2 days before induction of colitis and for 5 consecutive days after induction of colitis. ^*P < 0.001 as compared to the saline control group. ^#P < 0.001 as compared to the acetic acid group.

Effects of different doses of Ginkgo-biloba (30, 60 and 120 mg kg⁻¹) on gross lesion score of acetic acid-induced colitis in rats

Values are expressed as mean ± S.E.M. of eight animals per group. The percentage reduction indicates the reduction of colonic lesion as compared to acetic acid group.