药食同源物质杜仲叶的安全性评价及保健功能研究进展

Safety assessment and health function of eucommia floium, a food-medicine homologous substance

杜仲叶为我国特产树木杜仲树的叶,于夏秋二季枝叶茂盛时采收。作为一种药食同源物质,系统评估杜仲叶安全性很有必要。现有文献显示,杜仲叶醇提取物小鼠急性经口毒性LD50>21.50 g/kg·bw;小鼠急性经口最大耐受剂量约为60 g/kg·bw;小鼠腹腔注射LD50范围2.57±0.15 g/kg·bw。大鼠28 d(或30 d)实验未观察到的损害作用剂量NOAEL为330 mg/kg·bw。连续8周大鼠实验观察到损害作用的最低剂量(LOAEL)为0.69 g/kg·bw。杜仲叶遗传毒性研究尚有争议,杜仲叶水提取物Ames试验(8~5000μg/皿)为阴性;小鼠骨髓嗜多染红细胞微核试验(2.5~10.0 g/kg·bw)为阴性;SOS/UMU实验(10~100 mg/ml)为阴性;DNA交联试验(0.1~10 mg/ml)为阴性;也有研究报道杜仲水煎剂在加与不加S9条件下均可诱发L5178Y细胞tk位点突变并导致染色体损伤,因此杜仲叶遗传毒性研究,应采用遗传项目组合方式,综合体内体外实验结果判定。杜仲叶已报道的保健功能,包括降压、降糖、降脂和抗氧化。

Eucommia floium are the leaves of Eucommia ulmoides trees, the specialty trees in China, which are harvested in summer and autumn. In order to develop and utilize the resources of Eucommia floium, a food-medicine homologous substance, it is necessary to systematically evaluate the safety of Eucommia floium. The existing literature shows that the acute oral toxicity test of water extract from Eucommia floium in mice is LD50>21.50 g/kg·bw, the maximum tolerance dose of acute oral extract in mice is about 60 g/kg·bw, and the range of intraperitoneal injection of LD50 in mice is 2.57±0.15 g/kg·bw. The dose of NOAEL, which is not observed in 28 days(or 30 days), is 330 mg/kg·bw. The lowest dose of(LOAEL) observed in experimental rats for 8 weeks is 0.69 g/kg·bw. The study on genotoxicity of Eucommia floium is controversial. The Ames test(8~5 000 μg/plate) of water extract from Eucommia floium is negative, the micronucleus test(2.5~10.0 g/kg·bw) of mouse bone marrow polychromatic erythrocytes is negative, the SOS/UMU test(10~100 mg/ml) is negative, and the DNA cross-linking test(0.1~10 mg/ml) is negative. However, some studies have shown that Eucommia ulmoides decoction can induce tk site mutation and chromosome damage in L5178 Y cells under the condition of +/-S9, genotoxicity of Eucommia ulmoides need genetic project combination to determine the result of in vivio and in vitro. Eucommia floium have health care functions, including hypotension, hypoglycemia, lipid lowering and antioxidation.