Phytochemical, cytotoxic, hepatoprotective and antioxidant properties of Delonix regia leaves extract

Hepatocellular carcinoma is considered the third most common cause of cancer-related death worldwide. Thus, the present study was designed to test for the first time the putative cytotoxic effect of Delonix regia extract, besides its hepatoprotective activity. In this context, this study targets four specific aims; first, the phytochemical investigation of D. regia extract which led to the isolation of seven flavonoid glycosides; Kaempferol 3-rhamnoside 1, Quercetin 3-rhamnoside 2, Kaempferol 3-glucoide 3, Kaempferol 3-rutinoside 4, Kaempferol 3-neohesperidoside 5, Quercetin 3-rutinoside 6 and Quercetin 3-glucoside 7. Second, the evaluation of in vitro cytotoxic activity of the extract, where the extract exhibited a potent cytotoxic effect against HepG2 cell line. Third, the hepatoprotective activity was investigated using carbon tetrachloride (CCl4)-induced liver injury. The plant extract at dose of 50, 100 and 200 mg/kg body weight reduced serum aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase as well as total and direct bilirubin in a dose dependent manner. The fourth aim was the investigation of the antioxidant activity of the extract as the treatment of rats with the extract at different doses significantly increased the liver tissue level of superoxide dismutase, catalase, reduced glutathione and total antioxidant capacity and decreased the level of malondialdehyde as compared to CCl4 treated group. The current findings concluded that the extract of D. regia possessed not only a significant anticancer effect against HepG2 cells, but also an effective and a dose dependent hepatoprotective and antioxidant activities due to the presence of flavonoids content.