中国红豆杉中主要紫杉烷类物质的分布研究

DISTRIBUTION OF TAXOL AND TAXANES IN YEW TREE

对中国红豆杉[Taxus chinensis(Pilg.)Rehd.]中的紫杉烷类化合物紫杉醇及两种重要前体巴卡亭III(B III)和10-脱乙酰巴卡亭III(10-DAB)的分布进行了研究.结果表明,紫杉醇的含量在同一棵树中的分布依主干皮、根皮、侧枝树皮、种子、须根、嫩枝、叶的次序递减,并发现侧枝茎中紫杉醇在横截面方向呈梯度分布,且紫杉醇含量最高部位是在次生木质层.10-DAB和B III在叶中含量最高,在须根中含量最低,叶子中10-DAB的含量达0.02%～0.03%,高于B III的含量.在2～3 a生的小树枝、叶中未检测到紫杉烷类物质,提示其合成可能与植株发育有关.紫杉醇在30 a 树龄的当年生嫩叶中春季高于秋季,而10-DAB在当年生和多年生的叶中积累都较多,且秋季比春季含量高.

The contents of taxol and its two important precursors,namely baccatin III(B III)and 10-deacetylbaccatin III (10-DAB) in various tissues of yew trees \[Taxus chinensis(Pilg.)Rehd.\] at different ages in different seasons were quantified by HPLC.The results indicated that the content of taxol decreased successively according to stem barks,root barks,lateral stem barks,seeds,fibres,twigs and young needles in a single tree.The gradient distribution of taxol concentration along radial direction of cross section of lateral stem was surveyed for the first time.It was found that the highest amount of taxol occurred in the secondary xylem rather than in the cortex of the lateral stem.The highest and the lowest contents of 10-DAB and B III among the parts of a tree occurred in needles and fibres,respectively.The content of 10-DAB in needles was in a range of 0.01% to 0.02%,higher than that of B III and taxol.The result of the absence of both taxol and related taxanes in needles from 2-3 years old yew tree indicated that the biosynthesis of taxanes may require related phase of the development of the plant.It was observed that the mature needles in the spring have higher amount of taxol than in autumn,while the case of 10-DAB was in reverse.The mechanisms of (biosynthesis) and accumulation of taxol were discussed through the analysis of the distribution of taxol and related (compounds) in T.chinensis(Pilg.)R..