Raphanus sativus L. var. caudatus Alef (RS)是一种具有营养和药用价值的泰国本土植物，具有抗癌活性，但仅限于体外。因此，研究了RS在大鼠肝癌初始阶段的化学预防作用。将致癌物Diethylnitrosamine (DEN)注入大鼠体内引发肝癌。在DEN注射的同时，口服水溶性(RS-H2O)或二氯甲烷萃取物(RS-DCM)。用免疫组织化学法检测谷胱甘肽S-转移酶胎盘型(GST-P)阳性部位和大鼠肝脏中的凋亡细胞，以指示初始阶段的癌变。通过以下方式研究化学预防的潜在机制：(a)抗突变活性；(b)肝脏第II期酶诱导；(c)肝脏促炎症细胞因子基因表达。结果显示，RS-DCM比RS-H2O更有效地降低DEN诱导的GST-P阳性部位和凋亡细胞。RS-DCM(苯酚和硫代谷氨酸含量)对抗肝癌的机制是：(1)阻断致癌物的活性；(2)提高第II期解毒酶；(3)抑制促炎症基因表达。相反，RS-H2O(苯酚含量)仅降低促炎症基因表达。总之，RS提取物由苯酚和异硫氰酸酯组成，对DEN诱导的肝癌表现出显著的化学预防活性。

Raphanus sativus L. var. caudatus Alef (RS) is an indigenous Thai plant with nutritional and medicinal values such as anticancer activity, but only in vitro. The chemopreventive effects of RS were, therefore, investigated in the initial stage of hepatocarcinogenesis in rats. Diethylnitrosamine (DEN), a carcinogen, was intraperitoneally injected into rats to induce liver cancer. Along with the DEN injection, either aqueous (RS-H2O) or dichloromethane (RS-DCM) extract was administered orally. Immunohistochemistry was used to detect glutathione S-transferase placental (GST-P) positive foci and apoptotic cells in rat livers as indicators of initial-stage carcinogenesis. The underlying mechanisms of chemoprevention were investigated with (a) antimutagenic activity, (b) hepatic phase II enzyme induction, and (c) hepatic pro-inflammatory cytokine gene expression. The results showed that RS-DCM was more potent than RS-H2O in decreasing GST-P positive foci and apoptotic cells induced by DEN. The mechanisms of RS-DCM (phenolics and sulforaphene contents) against liver carcinogenesis (1) block the activity of carcinogens; (2) elevate phase II detoxifying enzymes; and (3) suppress the pro-inflammatory gene expression. RS-H2O (phenolics contents), in contrast, only decreases pro-inflammatory gene expression. In conclusion, the RS extract consisting of phenolics and isothiocyanates exerted significant chemopreventive activity against DEN-induced liver carcinogenesis.