研究顯示人類癌症的發生與 DNA 受傷害有關。海巴戟天俗稱諾麗，生長在熱帶亞洲，其被應用在很多的傳統醫療，包括癌症。本研究利用彗星試驗探討海巴戟天褐莖乙醇萃取液 (BSE) 與其各正己烷、正丁醇、乙酸乙酯及水層分配相，保護人類淋巴球細胞免於遭受過氧化氫誘發 DNA 氧化傷害的效果。結果顯示 BSE 中同時含有抗氧化及促氧化的物質存在，其中正-己烷分配相 (BSE-H)，濃度在25~50μg/mL 時，不具基因毒性，且具有顯著保護淋巴球細胞免於遭受到過氧化氫傷害的效應，綜合本研究顯示 BSE-H 中的成分清除 DPPH 自由基的能力不高，多屬非多酚類物質，並具有油溶性特性。 Studies have shown that the incidences of human cancer are associated with DNA damage. Morinda citrifolia commonly known as Noni, is a plant typically found in the tropical Asia. The plant has been used traditionally as a folk remedy for many diseases including cancers. In this study, we examined the effects of the ethanolic extracts from the Noni’s brown stem (BSE), and n-hexane-, n-butanol-, ethyl acetate-, and H2O-soluble partitioned phases obtained from BSE on protective from hydrogen peroxide induced DNA damage within purified healthy human blood lymphocyte using comet assay. Results showed that BSE contains antioxidants and pro-oxidants dual components. Furthermore, n-hexane partitioned phase from BSE (BSE-H) at concentration of 25-50 μg/mL had significant protection against oxidative stress induced by H2O2. From these findings, we suggest that ingredients from BSE-H belong to hydrophobic properties, mostly non-polyphenolics and lower in the scavenging ability of DPPH radical.