大蒜精油之安全性評估試驗

Abstract

大蒜（Allium sativum L.）已具有數千年的食用歷史，為一般公認之安全食品（generally recognized as safe, GRAS）。大蒜的有機含硫化合物為其獨特氣味與主要生理活性的來源，其中又以水蒸氣蒸餾萃取濃縮而成的大蒜精油（garlic essential oil, GEO）含有最多的油溶性活性成分。GEO的研究相當廣泛，動物實驗指出GEO可降低肝臟脂肪堆積、氧化與發炎反應，減緩高脂及酒精誘導的脂肪肝。在人體流行病學研究中，給予受試者六個月0.25 mg/kg bw/day GEO後，可調節血清膽固醇及三酸甘油脂，具有降低心血管疾病與冠狀動脈硬化風險的功效。但過去文獻提出大蒜可能產生的副作用，如下痢、腸胃道受損、血清蛋白降低、貧血與抗凝血等，然而目前GEO的安全性資料尚未被完整建立，顯示其安全性評估的需求與迫切性。因此，本實驗假說為GEO在功效性及建議攝取劑量下，可能不具造成基因毒性、動物急毒性與亞急毒性。本研究以微生物、細胞及動物實驗對GEO進行全面性的安全評估。在Ames test實驗結果顯示，GEO在0.05、0.1、0.125、0.25與0.5 mg/plate劑量下，不具造成沙門氏菌TA98、TA100、TA102、TA1535與TA1537產生致突變。而在細胞chromosome aberration實驗結果亦顯示GEO在1、1.5、2.5、5與10 µg/ml劑量下未引起中國倉鼠卵巢細胞（Chinese hamster ovary cells, CHO-K1）產生染色體畸變率的上升。進一步以GEO建議攝取量（0.25 mg/kg bw/day）之安全係數60、100與200倍進行動物實驗，在分別餵食ICR小鼠GEO（15, 25與50 mg/kg bw/day）24及48小時後，以眼窩採血進行微核試驗，結果顯示GEO在各劑量下皆不具引發小鼠體內微核發生比率上升。此外，在14天急毒性及28天亞急毒性試驗中，顯示GEO（15, 25與50 mg/kg bw/day）未使動物行為、體重、攝食、攝水量及臟器重量產生異常，血液參數及生化數值皆在正常範圍內，且在肝、心、脾、肺及腎臟等組織H&E染色分析中，亦無出現病變情形。綜合上述之結果，GEO在人體建議攝取量及具有功效性劑量下，不具造成基因毒性、動物急性與亞急毒性的產生，因此目前本實驗結果中，無觀察到不良反應之最高劑量（no-observed-adverse-effect level, NOAEL）為高於GEO 50 mg/kg bw/day。

Garlic (Allium sativum L.) has been used as both food and medicine for thousands of years. Garlic is listed as generally recognized as safe (GRAS) by the U.S. Food and Drug Administration. Recent studies found that biological activities are attributed to the organosulfur compounds in garlic. Garlic essential oil (GEO) is typically obtained by steam distillation the yield is around 0.2-0.5%. Many epidemiologic studies report that consumption of GEO (0.25 mg/kg bw/day) can reduce the cardiovascular disease and coronary arteriosclerosis, by decreasing the serum cholesterol and triglyceride level. Although, garlic has been widely used, it is commonly known that excessive consumption of garlic may cause some side effects, including diarrhea, gastrointestinal damage, reduced serum protein, anemia, anticoagulant etc. However, the GEO safety data has not been established. Nowadays, there are an increase of using garilic and supplementary products, thus, it is important and urgent to assess the GEO safety. The hypothesis of this study is GEO may not cause animal subacute toxicity and genotoxicity hazard under the efficacy dosage and intake recommendations. The aim of this study is to evaluate the genotoxicty, animal acute, and subacute toxicity of GEO through Ames, chromosome aberration, micronucleus and animal test. The Ames test results indicted that GEO in 0.05, 0.1, 0.125, 0.25, and 0.5 mg/plate doses, did not cause Salmonella typhimurium TA98, TA100, TA102, TA1535, and TA1537 mutant. The results also demonstrated that at 1, 1.5, 2.5, 5, and 10 µg/ml of GEO did not cause the increasemet of CHO-K1 cells chromosome aberration rate. Under the safety factor of 60, 100, and 200 times of recommended intake dose (0.25 mg/kg bw/day) of the GEO (15, 25, and 50 mg/kg bw/day) did not cause ICR mice peripheral blood micronucleus generation rate increase after 24 and 48 hours. In addition, GEO at dose 15, 25, and 50 mg/kg bw/day did not affect abnormal behavior, body weight, food intake, water intake, and histopathological analysis of organ tissue in ICR mice. Futhermore, no significant abnormal finding in blood biological parameter values in ICR mice. In conclusion, GEO did not cause genotoxicity, and the no-observed-adverse-effect level for GEO derived from the results of the present study was considered to be greater than 50 mg/kg bw/day.