Oral Administration of Trapa taiwanensis Nakai Fruit Skin Extracts Conferring Hepatoprotection from CCl4-Caused Injury

As a folk medicine, the hot-water infusion of water caltrop fruits has been used to protect the liver. In this study, the outer skins of mature water caltrop fruits (Trapa taiwanensis Nakai) were removed, forced-air-dried, pulverized, and subjected to extraction with hot water, and the infusion was lyophilized and pulverized to prepare a hot water extract of T. taiwanensis (HWETT). HWETT was subjected to assays of α,α-diphenyl-β-picrylhydrazyl scavenging activity, reducing power, Trolox equivalent antioxidant capacity, and antioxidative potency, and all determinations showed HWETT to be a potent antioxidant. As further analyzed with LC-MS, two major HPLC-detected components were elucidated as gallic acid and ellagic acid. Hepatoprotective activity of HWETT was assessed with Sprague−Dawley male rats by oral administration. Six groups of rats (n = 8 for each) were respectively treated, namely, control, CCl4 (20% CCl4/olive oil by 2.0 mL/kg bw), CCl4 and Silymarin (200 mg/kg bw), CCl4 and low HWETT dose (12....