Abstract
Paclitaxel (Taxol®) has inhibitory effects against a variety of cancer cells. It is, however, still expensive due to limited production. Callus culture of Taxus species is one of the promising strategies for the cheap production. However, accumulation of Taxol released to the culture medium reduces the callus growth and the Taxol productivity due to the feedback inhibition of Taxol. In this study, suspension callus culture of T. baccata was carried out in an organic solvent/medium two-phase system to make in situ extraction and production of Taxol effective. Appropriate organic solvents for this purpose were chosen from a variety of organic solvents such as hydrocarbons, fatty alcohols, triglycerides and aromatic hydrocarbons. Hexane (HX), nonone (NN), decane (DC), dodecane (DD), hexadecane (HD), octadecane (OD), lauryl alcohol (LA), tricaprylin (TC) and triacetin (TA) were used in the callus culture to examine their cytotoxicity and Taxol productivity. NN and HX having low log P values of 3-5 inhibited the callus growth. Hydrocarbons of the log P value more than 5 were non-cytotoxic and increased Taxol productivity. TA, TC and LA enhanced Taxol productivity by a factor of more than 2 compared to the control culture. These data indicated that fatty alcohols and triglycerides were effective to enhance the callus growth and Taxol productivity. In addition, methyl jasmonate (MJ), a well-known elicitor, was solubilized in the selected organic solvent, LA. The effect of MJ was investigated. The callus growth and the Taxol production increased with the increase of MJ concentration. The callus growth and the Taxol productivity at 22 mM of MJ were 1.5 and 2 times higher than those of the control culture, respectively.
