Effect of Sanguis draconis (a dragon's blood resin) on streptozotocin- and cytokine-induced ß-cell damage, in vitro and in vivo.

The study was to examine the effects of Sanguis draconis ethanol extract (SDEE) on streptozotocin (STZ)- and cytokine-induced ß-cell damage. In vitro, SDEE did not cause cytotoxicity below 200 µg/ml, and can prevent STZ (5mM)-induced cell death and apoptosis below 100 µg/ml on RIN-m5F cells. SDEE inhibits IL-1ß/IFN-γ-stimulated NO, TNF-α release, and iNOS expression. Furthermore, SDEE suppressed the IL-1ß/IFN-γ- or STZ-induced p65 expression of NF-κB, which is associated with inhibition of IκB-α degradation. In vivo, treatment of ICR mice with STZ (100 mg/kg, i.p. single injection) resulted in hyperglycemia and hypoinsulinemia, which was further evidenced by blood glucose and plasma insulin. The diabetogenic effects of STZ were completely prevented when mice were orally administered with SDEE for 3 weeks, however, the blood glucose and plasma insulin showed no significant change after SDEE administration alone. In addition, SDEE also can inhibit STZ-induced iNOS protein expression, pancreatic injury and lipid peroxidation. In conclusions, the molecular mechanism by which SDEE inhibits iNOS gene expression appears to involve the inhibition of NF-κB activation. These results suggest the possible therapeutic value of S. draconis and could be potentially developed into a novel drug for preventing the progression of diabetes mellitus.

Myrrh mediates haem oxygenase-1 expression to suppress the lipopolysaccharide-induced inflammatory response in RAW264.7 macrophages.

OBJECTIVES: To elucidate a novel anti-inflammatory mechanism of myrrh against lipopolysaccharide (LPS)-induced inflammation. METHODS: RAW264.7 macrophages were cultured in DMEM and then cells were treated with LPS or LPS plus a myrrh methanol extract (MME) for 24h. The culture medium was collected for determination of nitric oxide (NO), prostaglandin (PG)E(2) , interleukin (IL)-1ß, and tumour necrosis factor (TNF)-α, and cells were harvested by lysis buffer for Western blot analysis. KEY FINDINGS: Our data showed that treatment with the MME (1∼100µg/ml) did not cause cytotoxicity or activate haem oxygenase-1 (HO-1) protein synthesis in RAW264.7 macrophages. Furthermore, the MME inhibited LPS-stimulated NO, PGE(2) , IL-1ß and TNF-α release and inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 protein expression. Zn(II) protoporphyrin IX, a specific inhibitor of HO-1, blocked the inhibition of iNOS and COX-2 expression by the MME. CONCLUSIONS: These results suggest that among mechanisms of the anti-inflammatory response, the MME inhibited the production of NO, PGE(2) , IL-1ß and TNF-α by downregulating iNOS and COX-2 gene expression in macrophages and worked through the action of HO-1.

Protective effects of Ginkgo biloba extract on the ethanol-induced gastric ulcer in rats.

AIM: To evaluate the preventive effect of Ginkgo biloba extract (GbE) on ethanol-induced gastric mucosal injuries in rats. METHODS: Female Wistar albino rats were used for the studies. We randomly divided the rats for each study into five subgroups: normal control, experimental control, and three experimental groups. The gastric ulcers were induced by instilling 1 mL 50% ethanol into the stomach. We gave GbE 8.75, 17.5, 26.25 mg/kg intravenously to the experimental groups respectively 30 min prior to the ulcerative challenge. We removed the stomachs 45 min later. The gastric ulcers, gastric mucus and the content of non-protein sulfhydryl groups (NP-SH), malondialdehyde (MDA), c-Jun kinase (JNK) activity in gastric mucosa were evaluated. The amount of gastric juice and its acidity were also measured. RESULTS: The findings of our study are as follows: (1) GbE pretreatment was found to provide a dose-dependent protection against the ethanol-induced gastric ulcers in rats; (2) the GbE pretreatment afforded a dose-dependent inhibition of ethanol-induced depletion of stomach wall mucus, NP-SH contents and increase in the lipid peroxidation (increase MDA) in gastric tissue; (3) gastric ulcer induced by ethanol produced an increase in JNK activity in gastric mucosa which also significantly inhibited by pretreatment with GbE; and (4) GbE alone had no inhibitory effect on gastric secretion in pylorus-ligated rats. CONCLUSION: The finding of this study showed that GbE significantly inhibited the ethanol-induced gastric lesions in rats. We suggest that the preventive effect of GbE may be mediated through: (1) inhibition of lipid peroxidation; (2) preservation of gastric mucus and NP-SH; and (3) blockade of cell apoptosis.

Effects of Ginkgo biloba extract on cytoprotective factors in rats with duodenal ulcer.

AIM: To investigate the effects of Ginkgo biloba extract on cytoprotective factors in rats with duodenal ulcer. METHODS: Sprague-Dawley rats were randomly divided into four groups: sham operation without ginkgo, sham operation with ginkgo, duodenal ulcer without ginkgo, and duodenal ulcer with ginkgo. Rats with duodenal ulcer were induced by 500 mL/L acetic acid. Rats with ginkgo were intravenously injected with Ginkgo biloba extract from the tail at a dose of 0.5 mg/(kg/d) for 7 and 14 days. RESULTS: Pathological result showed that duodenal ulcer rats with ginkgo improved mucosal healing and inflammation compared with those without ginkgo after 7 d treatment. After 14 d treatment, duodenal ulcer rats with ginkgo significantly increased weight gain (34.0+/-4.5 g versus 24.5+/-9.5 g, P<0.05) compared with those without ginkgo. Duodenal ulcer rats significantly increased cell proliferation (27.4+/-4.0 and 27.8+/-2.3 BrdU-labeled cells in duodenal ulcer rats with and without ginkgo versus 22.4+/-3.5 and 20.8+/-0.5 BrdU-labeled cells in sham operation rats with and without ginkgo, P<0.05) compared with sham operation rats. Mucosal prostaglandin E(2) concentration significantly increased by 129% (P<0.05) in duodenal ulcer rats with ginkgo compared with that in those without ginkgo. Duodenal ulcer rats without ginkgo significantly decreased superoxide dismutase activity in the duodenal mucosa and erythrocytes (19.4+/-6.7 U/mg protein versus 38.1+/-18.9 U/mg protein in the duodenal mucosa, and 4.87+/-1.49 U/mg protein versus 7.78+/-2.16 U/mg protein in erythrocytes, P<0.05) compared with sham operation rats without ginkgo. However, duodenal ulcer rats with ginkgo significantly increased erythrocyte superoxide dismutase activity (8.22+/-1.92 U/mg protein versus 4.87+/-1.49 U/mg protein, P<0.05) compared with those without ginkgo. Duodenal ulcer rats without ginkgo significantly increased plasma lipid peroxides (4.18+/-1.12 micromol/mL versus 1.60+/-1.10 micromol/mL and 1.80+/-0.73 micromol/mL, P<0.05) compared with sham operation rats without ginkgo and duodenal ulcer rats with ginkgo during the experimental period. CONCLUSION: Ginkgo biloba extract can improve weight gain and mucosal healing in duodenal ulcer rats by the actions of cytoprotection and antioxidation.