Vance N C, Kelsey R G, Sabin T E
USDA Forest Service, Pacific Northwest Research Station, Corvallis, OR 97331.
Phytochemistry. 1994 Jul;36(5):1241-4. doi: 10.1016/s0031-9422(00)89644-2.
Analysis of seven taxanes: taxol, baccatin III, 10-deacetyltaxol, 10-deacetylbaccatin III, 7-xylosyl-10-deacetyltaxol, cephalomannine and brevifoliol in extracts from bark and foliage of pacific yew (Taxus brevifolia) showed a gradient of decreasing concentration from stem base to branch tip. This decrease is attributed to the generally higher concentration of taxanes in the phloem tissue and the decrease in inner bark thickness from base to branch tip. Analysis of taxanes extracted from stem bark and needles sampled over a growing season showed that most taxane concentrations were significantly lower in the needles than in the bark. Typically, taxane concentrations in bark increased from May through August; whereas, in needles, concentrations changed little during that period. Two exceptions were baccatin III, which in the summer reached levels equivalent to bark, and brevifoliol which increased from March to August, reaching levels in needles nine times greater than bark.
对太平洋紫杉（短叶红豆杉）树皮和树叶提取物中的七种紫杉烷进行分析：紫杉醇、巴卡亭III、10-去乙酰紫杉醇、10-去乙酰巴卡亭III、7-木糖基-10-去乙酰紫杉醇、三尖杉宁碱和短叶醇，结果显示从茎基部到枝尖浓度呈递减梯度。这种减少归因于韧皮部组织中紫杉烷的浓度通常较高，以及从基部到枝尖内皮厚度的减少。对在一个生长季节采集的茎皮和针叶中提取的紫杉烷进行分析表明，针叶中大多数紫杉烷的浓度显著低于树皮中的浓度。通常，树皮中紫杉烷的浓度从5月到8月增加；而在针叶中，在此期间浓度变化不大。两个例外是巴卡亭III，其在夏季达到与树皮相当的水平，以及短叶醇，其从3月到8月增加，针叶中的含量比树皮高九倍。
