中药蓼大青叶及其伪品的nrDNA ITS区序列的测定

中药蓼大青叶的基源为蓼科蓼属植物蓼蓝（Polygonum tinctorium Ait),同属植物的水蓼（辣蓼）,（P.hydropiperL.)的叶常作其伪品,本文采用PCR直接测序法,首次测定了它们的核糖体DNA ITS区序列,结果显示,两者充列长度（ITS1,5,8S,ITS2）均为646bp,序列间共有28个变异位点,本研究为产蓝植物的DNA分子鉴定提供了必要的序列资料。     

Identification of a drimenol synthase and drimenol oxidase from Persicaria hydropiper,involved in the biosynthesis of insect deterrent drimanes

The sesquiterpenoid polygodial, which belongs to the drimane family, has been shown to be an antifeedant for a number of herbivorous insects. It is presumed to be synthesized from farnesyl diphosphate via drimenol, subsequent C‐12 hydroxylation and further oxidations at both C‐11 and C‐12 to form a dialdehyde. Here, we have identified a drimenol synthase (PhDS) and a cytochrome P450 drimenol oxidase (PhDOX1) from Persicaria hydropiper. Expression of PhDS in yeast and plants resulted in production of drimenol alone. Co‐expression of PhDS with PhDOX1 in yeast yielded drimendiol, the 12‐hydroxylation product of drimenol, as a major product, and cinnamolide. When PhDS and PhDOX1 were transiently expressed by agro‐infiltration in Nicotiana benthamiana leaves, drimenol was almost completely converted into cinnamolide and several additional drimenol derivatives were observed. In vitro assays showed that PhDOX1 only catalyses the conversion from drimenol to drimendiol, and not the further oxidation into an aldehyde. In yeast and heterologous plant hosts, the C‐12 position of drimendiol is therefore likely to be further oxidized by endogenous enzymes into an aldehyde and subsequently converted to cinnamolide, presumably by spontaneous hemiacetal formation with the C‐11 hydroxyl group followed by oxidation. Purified cinnamolide was confirmed by NMR and shown to be deterrent with an effective deterrent dose (ED₅₀) of about 200–400 μg g^?1 fresh weight against both whiteflies and aphids. The putative additional physiological and biochemical requirements for polygodial biosynthesis and stable storage in plant tissues are discussed.     

蓼二醛对蚜虫的拒食活性

辣蓼(Polygonum hydropiper L.)中的天然产物蓼二醛((-)-POLYGODIAL)具有很好的昆虫拒食活性。本文介绍了提取、分离的方法和含量测定。结果表明,我国辣蓼叶中含有蓼二醛约为0,08%。合成的蓼二醛在室内对空气、光和热的半衰期分别为34.6天、33.8天和15,6天。室内外生测结果表明,天然蓼二醛的乙醚提取物对蚜虫有很好的柜食活性。