Anti-Hangover and Hepatoprotective Effects of the Leaf Extract of Thunbergia laurifolia in Sprague–Dawley Rats

Background/Objectives: The present study aims to evaluate the anti-hangover and hepatoprotective activities of the leaf extract of T. laurifolia in experimental animals. Methods: Two experiments were conducted that involved giving a single dose of the leaf extract of T. laurifolia (1, 10, or 100 mg/kg body weight) to rats 30 min either before or after administration of 40% ethanol (5 g/kg body weight). The locomotor activity of the rats was measured before and after receiving the test substances. Blood samples were collected to determine the ethanol, acetate, and liver enzyme levels. Liver tissues were collected to evaluate alcohol-metabolizing enzymes, antioxidant enzyme activities, and antioxidant levels. Results: Administration of the leaf extract of T. laurifolia to the rats prior to ethanol increased locomotor activity and reduced blood ethanol levels. The extract also prevented changes in liver enzyme levels and demonstrated antioxidant activity by scavenging free radicals resulting from ethanol-induced oxidative stress. Conversely, rats administered the leaf extract of T. laurifolia after receiving ethanol were able to reduce the elevated liver enzyme levels back to normal levels, and probably helped to inhibit the harmful effects of free radicals by stimulating the synthesis and/or activities of antioxidant enzymes. Administration of the leaf extract of T. laurifolia either before or after ethanol exposure was able to reduce the activity of an alcohol-metabolizing enzyme as well as reduce blood acetate levels. Conclusions: In summary, receiving the leaf extract of T. laurifolia before alcohol consumption could probably help to reduce hangover symptoms and was shown to have hepatoprotective effects superior to receiving the extract after alcohol consumption.