將海巴戟天乙醇萃取物上清液(LES)經HPLC RP-18管柱劃分，在吸光值A280條件下，使LES劃分成五個分劃物(fractions I-V)，用Standard （細胞膜存在的條件） 與 Lysed-cell comet assay（將人類淋巴球細胞的細胞膜移除的條件)做體外實驗，研究LES與fractions I-V在仿體內環境中的效用。結果顯示LES有明顯的濃度依存且有促氧化效應，而且LES中的一些成分可能穿越細胞膜和在Standard assay部分能間接保護DNA，可能是經由與細胞膜或是細胞內的成分產生交互作用。結果也顯示某些成分，fractions I與III(rutin-like)是不能穿越細胞膜的，對於氧化壓力所引起傷害的保護機制是屬於間接。另外，fraction IV可以穿越細胞膜，直接地清除過氧化氫。然而在LES中fraction I、 IV是沒有基因毒性，fraction II 、V於基因毒性與促氧化裡扮演重要的角色。結論是fraction I、III、IV可能是在人類血液淋巴球細胞中對抗氧化壓力顯著的外生性抗氧化物質的重要關鍵。 The supernatant of ethanolic extracts from leaf of Morinda citrifolia (LES) were fractionated on a preparative HPLC RP-18 column with ethanol as eluate. Based on A280, the column was able to separate LES into five fractions (I-V). Standard (whole cell) and a modified version of the comet assay (Lysed-cell comet assay, that is cell membrane removed) was employed to investigate the effect in vitro of LES and its five fractions in the subcellular environment. Results showed that LES has a significantly concentration-dependent pro-oxidant effect. Besides, some components of LES are likely to be membrane permeable and have an indirect DNA protection in whole cells mediated via interaction with membrane and / or intracellular components. The results also indicate that some components of fraction I and III (rutin-like) are membrane impermeable and have an indirect protection mechanism against oxidative stress. In addition, fraction IV is membrane permeable and directly scavenging hydrogen peroxide. Although fraction I and IV have no genotoxicity effect, fraction II and V may be played a major role for genotoxicity and / or pro-oxidant effect in the LES. In conclusion, fraction I, III and IV might contribute significantly to exogenous antioxidants which are crucial in combating oxidative stress to human blood lymphocyte.
