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Acute oral administration of absolute ethanol (1.0 ml/kg) to fasting rats produced extensive necrosis of the gastric mucosa within 1 h. Pretreatment 30 min before administration of ethanol with oral tetramethylpyrazine (TMP) prevented this necrosis. Gross examination of the gastric mucosa of rats that received TMP showed fewer gastric lesions than that of rats who did not receive TMP. TMP pretreatment in rats exhibited superoxide scavenging activity in absolute ethanol-induced lipid peroxidation in gastric mucosal homogenates. TMP added in vitro to gastric homogenates made from control rats also showed scavenging activity. We conclude that the gastric protective mechanism of TMP could be attributed, at least in part, to its ability to inhibit lipid peroxidation and hence indirectly protect the gastric mucosa from oxidative stress.

Oxygen free radicals have been suggested to be a contributory factor in complications of diabetes mellitus. In the present study, we investigated the effect of tetramethylpyrazine (TMP) (10, 25 and 50 mg/kg), an active component of a Chinese medicinal plant Ligusticum wallich Franch (Chuanxiang), on streptozotocin (STZ)-induced diabetic male ICR mice. STZ was injected as a single daily dose (4 mg/kg i.p. in buffered citrate solution, pH 4.0) for one week. A single daily dose of TMP (10, 25 or 50 mg/kg i.p.) was administered for 2 weeks to the STZ-induced diabetic mice immediately following 1 week STZ induction. Plasma glucose and serum blood urea nitrogen (BUN) concentrations were estimated at the time of sacrifice. Malonialdehyde (MDA) formation was measured from the liver and kidney tissues. TMP dose dependently inhibited glucose concentration and BUN elevation. TMP also remarkably reduced the degree of lipoperoxidation. Our results indicate that TMP may be an effective agent for treatment of diabetes mellitus complications with oxidative stress.

Acute p.o. administration of 99.5% ethanol (0.1 ml) to fasted mice produced heart toxicity. Pretreatment with p.o. administration of tetramethylpyrazine (TMP) could prevent such toxicity effectively and dose-dependently. The maximal antioxidative effect against 99.5% ethanol-induced heart toxicity could be observed at 1 hour after TMP administration. In order to further investigate the heart protective mechanism of TMP, both lipid peroxidation level in vivo and superoxide scavenging activity were conducted. TMP exhibited a dose-dependently anti-lipid peroxidation effect in mice heart homogenate, and results indicated that 99.5% ethanol-induced intoxicated mice hearts have higher malonic dialdehyde (MDA) levels compared with those in TMP administrated mice hearts. These results suggest that the potentially heart protective mechanism of TMP could be contributed, at least in part, to its prominent anti-lipid peroxidation and anti-free radical formation effects, hence it could protect the heart from lipid peroxidation-induced heart toxicity.

In this study, the intraperitoneal administration of 1 mg/kg thioacetamide (TAA) produced hepatotoxicity in mice. The increase in serum SGOT and SGPT produced at 24 h by this regimen was decreased in a dose-dependent manner by coadministration of tetramethylpyrazine (TMP; 10, 25 and 50 mg/kg). A rise in serum interleukin-2 was similarly prevented. Increased concentrations of malondialdehyde (MDA) generated in vitro in liver homogenates prepared from TAA-treated mice were decreased by TMP treatments. The increase in MDA produced by TAA was also prevented by in vitro addition of TMP to liver homogenates. These results suggest that part of the hepatocellular injury induced by TAA is mediated by oxidative stress caused by the action of cytokines through lipid peroxidation. TMP appears to act by preventing lipid peroxidation.

Acute administration of absolute ethanol (10 ml/kg) per os to fasted mice produced extensive renal failure as measured by a rise in blood urea nitrogen and creatinine. Pretreatment with oral administration of tetramethylpyrazine (TMP) prevented such failure. The maximal effect against absolute ethanol-induced renal failure could be observed 1 h after TMP administration. In order to further investigate the renal protective mechanism of TMP, experiments on lipid peroxidation and superoxide scavenging activity were conducted. Renal homogenates made from mice treated with ethanol showed that TMP pretreatment had an antioxidant effect. Mice in acute renal failure had higher malonic dialdehyde concentrations than those pretreated with TMP. The renal protective mechanism of TMP was attributed, in part, to its prominent superoxide scavenging effect, which protects the kidney from superoxide-induced renal damage.

2,3,5,6-Tetramethylpyrazine (TMP) is well known as a true calcium antagonist. The aim of this study was to investigate the hepatoprotective and therapeutic effects of TMP on acute econazole-induced liver injury. The hepatological effect of various concentrations of TMP was first assessed by the biochemical assays of SGOT and SGPT and then by hepatohistological microscopic examination. The dose-response relationship of liver injury induced by various doses of econazole was observed simultaneously from serum biochemical assay of SGOT and SGPT, and also from hepatohistological microscopic examination, by determination of the hepatoprotective effects of various concentrations of TMP on SGOT and SGPT elevation induced by a hepatotoxic dose of econazole (300 mg/kg). The inhibitory effect of various concentrations of TMP or vitamin E (positive control, 0.5 mM in vitro, 0.69 mM in vivo) on FeCl 2 -induced (in vitro) or econazole-induced (in vivo) lipid peroxidation was also investigated. The superoxide scavenging activity of various concentrations of TMP in econazole-damaged rat liver homogenate was assessed by the cytochrome C reduction method. Results showed that the hepatoprotective effect of TMP might be, at least in part, due to its inhibitory ability on membrane lipid peroxidation and free radical formation, or due to its free radical scavenging ability. Improvement of serum transaminases and MDA levels in rat liver homogenate, hepatohistological microscopic examination, and assessment of free radical scavenging activity by the cytochrome C reduction method were used to detect hepatoprotective and therapeutic effects of TMP on acute econazole-induced liver injury.