The Effect of Route of Administration in Thymoquinone Toxicity in Male and Female Rats

The maximum tolerated dose for intraperitoneal injection and oral ingestion of thymoquinone was determined in male and female Wistar rats. A range of dose levels of thymoquinone: 20, 30 and 40 mg/kg body weight for intraperitoneal injection and 200, 300 and 500 mg/kg body weight for oral ingestion were tested for acute toxicity in rats. The results showed that the maximum tolerated dose for intraperitoneal injection was 22.5 mg/kg in male rats and 15 mg/kg in females, whereas for oral ingestion it was 250 mg/kg in both male and female rats. There were different signs of toxicity shown in rats which received intraperitoneal injection from those that received oral ingestion of thymoquinone. Rats which received intraperitoneal injection of thymoquinone showed toxicity signs which were related to acute pancreatitis. Meanwhile, rats which received oral ingestion of thymoquinone showed transient toxicity signs. Two deaths were reported at dose of 500 mg/kg as a result of bowel obstruction complications. The data presented in this study indicate that the route of administration of thymoquinone could have an influence on thymoquinone toxicity outcome in both genders.