喜树碱和10—羟基喜树碱受喜树生长发育调控的不同特点

为了揭示喜树碱（camptothecin,CPT)和10-羟基喜树碱（10-hydroxycamptothecin,HCPT)在喜树（Camptotheca acuminata Decaisne)体内代谢的生理调控机制及这两种类似物之间的关系和作用。运用高效液相色谱技术对种子形成,成熟,萌发和幼苗生长过程中喜树三和10-羟基喜树碱的代谢动态进行了全面的研究。结果表明,喜树碱相对稳定地存在于成熟的幼嫩的组织中;10-羟基喜树碱特异性地积累在乳熟期的种子,种芽的子叶,幼嫩的真叶等幼嫩组织中,随着组织的进一步发育和成熟,其含量快速减少,成熟组织中积累极少,并且这两种生物碱的代谢在时间和数量上都呈现出相互消长的特点,由此推断,这两种生物碱不同程度地受生长发育调控的特点可能与喜树的化学防御策略密切相关。并且,它们之间可以相互转化以充分利用有限的氮素资源。     

喜树幼苗中喜树碱和10-羟基喜树碱对热激的响应特点和意义

植物在长期的生态环境适应过程中,产生了包括生物碱在内的大量次生代谢物。本文以我国特有树种——喜树(Camptotheca acuminata Decaisne)为材料,研究其不同器官中喜树碱(camptothecin,CPT)和10-羟基喜树碱(10-hydroxycamptothecin,HCPT)在不同热激温度和时间情况下的含量变化。CPT和HCPT变化呈现出较好的相互消长关系,并且分别在38℃和40℃达到各自的峰值,比以丙二醛和叶绿素为指标的致死温度低了2-4℃：HCPT在热激过程中的变化较CPT活跃;极易受到攻击和伤害的嫩叶中的生物碱含量变化最大。由此推断,CPT和HCPT遵循“幼嫩和生殖器官优先保护”的原则,从而有效地缓解了高温胁迫,并且HCPT和CPT代表了不同的防御策略。     

喜树幼苗中喜树碱和10-羟基喜树碱对热激的响应特点和意义

植物在长期的生态环境适应过程中,产生了包括生物碱在内的大量次生代谢物.本文以我国特有树种--喜树(Camptotheca acuminata Decaisne)为材料,研究其不同器官中喜树碱(camptothecin,CPT)和10-羟基喜树碱(10-hydroxycamptothecin,HCPT)在不同热激温度和时间情况下的含量变化.CPT和HCPT变化呈现出较好的相互消长关系,并且分别在38℃和40℃达到各自的峰值,比以丙二醛和叶绿素为指标的致死温度低了2~4℃;HCPT在热激过程中的变化较CPT活跃;极易受到攻击和伤害的嫩叶中的生物碱含量变化最大.由此推断,CPT和HCPT遵循"幼嫩和生殖器官优先保护"的原则,从而有效地缓解了高温胁迫,并且HCPT和CPT代表了不同的防御策略.     

抗癌药物喜树碱生产工艺的研究

前言抗癌药物喜树碱是含在我国南方的一种特产值物——珙桐科喜树(Camptothecaacuminata Decne.)中的一种生物碱,其结构为:在喜树的木、根皮和种子中都含有,以种子中台量为最高,主要成伪一为喜树碱 (c amPtothecine),其他还有10一径基喜树碱     

喜树碱的生物合成途径和代谢调控

喜树碱是一种具有抗肿瘤活性的萜类吲哚生物碱,最早是从我国特有植物喜树中分离获得的。本文概述喜树碱的天然分布合成途径和代谢调控的研究进展,并对喜树碱未来的生产和发展研究作了展望。     

不同产地和生长季节喜树叶中喜树碱含量测定

喜树(Camptotheca acuminata)是我国特有抗癌植物。本文通过测定不同产地的喜树幼嫩叶和成熟叶中喜树碱含量表明,均以四川都江堰所产喜树叶中喜树碱含量最高。不同生长月份的喜树嫩叶中喜树碱含量成一条单峰曲线,以7月喜树嫩叶中喜树碱的含量最高。     

不同产地和生长季节喜树叶中喜树碱含量测定

喜树（Camptotheca acuminata）是我国特有抗癌植物。本文通过测定不同产地的喜树幼嫩叶和成熟叶中喜树碱含量表明,均以四川都江堰所产喜树叶中喜树碱含量最高。不同生长月份的喜树嫩叶中喜树碱含量成一条单峰曲线,以7月喜树嫩叶中喜树碱的含量最高。     

喜树果中喜树碱和10-羟基喜树碱的匀浆提取工艺

以喜树果为原料,对匀浆法提取喜树碱和10-羟基喜树碱的工艺进行了研究,确定了最佳的工艺条件：提取溶剂为体积分数55％的乙醇,匀浆时间为8min,料液比为1：15（g／mL）。在此工艺条件下,喜树碱和10-羟基喜树碱的提取率分别为0．801‰和0．546‰。将该法与超声提取、回流提取、常温冷浸提取、水浴振荡提取进行了比较,结果表明,匀浆提取具有得率高、省时间等方面的优势,是一种高效提取喜树碱和10．羟基喜树碱的方法。     

接种时期对丛枝菌根喜树幼苗喜树碱含量的影响

喜树(Camptotheca acuminata)是我国特有的多年生亚热带落叶阔叶树种, 因其次生代谢产物喜树碱具有良好的抗肿瘤活性而受到人们的广泛关注。通过温室盆栽接种试验, 观察了喜树幼苗不同生长时期接种蜜色无梗囊霉(Acaulospora mellea)和根内球囊霉(Glomus intraradices)对喜树幼苗喜树碱积累的影响。结果表明接种两种丛枝菌根真菌均促进了喜树幼苗喜树碱的积累, 表现为喜树碱产量(单株幼苗所含的喜树碱量, 喜树碱含量与幼苗生物量的乘积)的显著提高。进一步分析发现, 接种丛枝菌根真菌导致幼喜树苗喜树碱产量的提高, 早期(幼苗出土20天)接种主要是源于喜树碱含量的提高, 特别是叶片喜树碱含量的提高, 而晚期(幼苗出土60天)接种则主要是源于幼苗生物量的增加。     

喜树毛状根的诱导及其喜树碱含量分析

研究了不同外植体类型(包括真叶、茎段、子叶及胚轴)、胚轴年龄和不同发根农杆菌菌株(包括A4、15834、R1601、C58C1)等因素对喜树毛状根诱导频率的影响,并用PCR对诱导出的毛状根进行了分子鉴定.结果表明:(1)最佳外植体为胚轴,5~10 d是胚轴最佳诱导年龄段,最佳诱导菌株为15834.(2)PCR鉴定结果表明,发根农杆菌的rolB基因已整合到喜树毛状根基因组中.(3)对不同菌株诱导的毛状根进行HPLC检测表明,C58C1菌株诱导的毛状根的喜树碱和羟基喜树碱含量最高,分别为1.219 mg/g和0.305 mg/g.研究结果为喜树碱的药源开发提供了一条新途径,并为进一步利用基因工程技术调控喜树碱的代谢合成奠定了基础.     

Extraction and composition of three naturally occurring anti-cancer alkaloids in Camptotheca acuminata seed and leaf extracts

Naturally occurring camptothecins (CPT) are important sources of chemotherapeutic agents for clinical treatment of cancer. Extraction of CPT from Camptotheca acuminata trees remains to be a cost-effective way in the supply equation compared with a total synthesis. This study conducted a series of experiments to determine efficient solvent for the maximal extraction of CPT and its two derivatives, hydroxycamptothecin (HCPT) and methoxycamptothecin, from seeds and leaves of C. acuminata. Methanol as an extraction solvent demonstrated in seeds a significantly higher recovery of these three alkaloids than dichloromethane and acetone. Methanol concentrations at 70% in water resulted in maximum extraction of all the three alkaloids regardless of the type of plant materials. However, other strengths of methanol, lower or higher, either decreased the extracting power or showed no improvement in the extraction. Seed extract contained all the three alkaloids whereas leaf extract was absent of HCPT. A stable ratio of the three alkaloids was discovered but it was dependent upon seed or leaf extract of C. acuminata, which with various compositions can be produced. Ecological and medicinal implications of the leaf and seed extract characterized with different chemical compositions are discussed.     

滤光膜对喜树幼苗叶片生长和喜树碱含量的影响

喜树 (Camptotheca acuminata)为中国特有树种 ,因其次生代谢产物喜树碱具有抗癌作用而闻名。通过用黄色、红色、蓝色 3种滤光膜对温室栽培的喜树幼苗进行遮光处理 ,研究了不同光照环境下喜树幼苗叶片生物量、叶绿素含量、光合作用和喜树碱含量的差异。结果表明在 30 d的遮光过程中 ,红膜和蓝膜遮光明显导致幼苗叶片生物量降低 ,黄膜遮光下幼苗叶片生物量在处理后 2 5 d才表现明显降低。不同滤光膜下幼苗叶片叶绿素含量先降低然后升高 ,遮光幼苗的叶绿素 a/ b明显低于日光幼苗。幼苗日最大净光合速率的顺序是 :日光 >黄膜 >红膜 >蓝膜。处理后第 2 0天 ,不同滤光膜下幼苗的光饱和光合速率 (Amax)、光饱和点 (Is)、光补偿点 (Ic)、最大表观量子效率 (AQYmax)都不同程度的低于日光幼苗。处理后第 10天至第 30天 ,遮光幼苗叶片喜树碱含量均显著高于日光下幼苗 ,以蓝膜下幼苗的喜树碱含量最高。蓝膜和黄膜下幼苗的喜树碱产量在后期处理中显著高于日光下幼苗 ,蓝膜下幼苗喜树碱产量在第 30天最高 ,是日光下幼苗的 2 .4 9倍。红膜下幼苗的喜树碱产量在第 10天后与日光下幼苗差异不显著。通过滤光膜遮光促进喜树碱在幼苗叶片中的积累 ,提高了叶片喜树碱产量 ,对喜树碱的生产实践有一定的意义     

Camptothecin and 10-hydroxycamptothecin accumulation in tender leaves of Camptotheca acuminata saplings after treatment with plant growth regulators

The effect of plant growth regulators (PGRs) on the accumulation of the alkaloid camptothecin (CPT) and its analogue 10-hydroxycamptothecin (HCPT) in tender leaves of Camptotheca acuminata saplings was studied. In screening experiments for PGRs, 40?mg/L dose of thiourea, triacontanol, and ascorbic acid (V_C) had no positive effects on the accumulation of the alkaloids. However, treatments with 40?mg/L of chlormequat chloride (CCC), choline chloride, paclobutrazol (PBZ), and daminozide (B₉) induced CPT and HCPT accumulation in both pre-harvest and postharvest stages. On that basis, five levels of PGRs at 0, 20, 40, 60, 80?mg/L were sprayed on tender leaves of C. acuminata saplings at pre-harvest and postharvest stages. Treatment by 40?mg/L CCC dramatically enhanced HCPT production by 308?% in pre-harvest, treatment by 60?mg/L CCC enhanced HCPT production by 100?% in postharvest. Spraying the leaves with 60?mg/L choline chloride resulted in 94?% increase of CPT and spraying with 40?mg/L of the PGRs reached 167?% increase of HCPT in the pre-harvest treatment, respectively; treatments with 60?mg/L choline chloride resulted in 64?% increase of CPT and 525?% increase of HCPT in postharvest, respectively. 52?% increase of CPT and 86?% increase of HCPT in pre-harvest, 22?% increase of CPT and 33?% increase of HCPT in postharvest were obtained by spraying leaves with 60?mg/L PBZ. Treatments with 40?mg/L B₉ had the highest impact on CPT (12?% increase in pre-harvest, 11?% increase in postharvest) and HCPT (167?% increase in pre-harvest, 173?% increase in postharvest) accumulation. The optimal PGR for obtaining the highest levels of CPT and HCPT was treatment with 60?mg/L choline chloride. In most case, the pre-harvest treatment was better than the postharvest one. These preliminary results suggest that the application of PGRs may be a useful and feasible method to increase CPT and HCPT levels in C. acuminata.     

Drought-induced in vivo synthesis of camptothecin in Camptothecaacuminata seedlings

Biosynthesis of secondary metabolites may be affected by environmental stimuli. In the present work, the effect of drought on the levels of an indole alkaloid (camptothecin [CPT]) in Camptotheca acuminata seedlings was investigated. Three seed sources, one from its native habitat in China and two from earlier introductions to the United States, in Texas and South Carolina, were used to compare response patterns. Progressive drought stress significantly reduced biomass production in the 3 seed sources of C. acuminata . Stomatal conductance closely followed the drought cycles, indicating the stress levels experienced by the plants. Leaf CPT concentrations showed a strong increase in the initial drought cycle in all seed sources except Texas, but they deviated in the second drought cycle, in which the South Carolina source continued to increase, whereas the Chinese and Texas seed sources decreased. CPT was inducible by drought, but the sustainability of the drought effect on leaf CPT concentrations was low and varied among seed sources.     

喜树的分泌结构及其与喜树碱积累的关系(英文)

为了揭示喜树碱(camptothecin,CPT)在喜树(Camptotheca acuminata Decne.)中的积累部位及积累规律,运用组织化学技术和高效液相色谱技术对喜树茎、叶中喜树碱的积累部位和含量进行了相关性分析。结果发现两类分泌结构与喜树碱积累密切相关:一类是分布于幼茎和幼叶表面的单细胞腺毛;另一类是分布于喜树幼茎和幼叶中的由1～2层细胞包围而成的分泌道。由此推断,喜树中的分泌结构为喜树碱的主要积累部位。     

喜树的分泌结构及其与喜树碱积累的关系

为了揭示喜树碱(camptothecin,CPT)在喜树(Camptotheca acuminata Decne.)中的积累部位及积累规律,运用组织化学技术和高效液相色谱技术对喜树茎、叶中喜树碱的积累部位和含量进行了相关性分析.结果发现两类分泌结构与喜树碱积累密切相关:一类是分布于幼茎和幼叶表面的单细胞腺毛;另一类是分布于喜树幼茎和幼叶中的由1～2层细胞包围而成的分泌道.由此推断,喜树中的分泌结构为喜树碱的主要积累部位.     

Influence of soil fertilization, plant spacing, and cokppicing on growth, stomatal conductance, abscisic acid, and camptothecin levels in Camptotheca acuminata seedlings

Changes in amount of the plant alkaloid, camptothecin (CPT), were investigated in field-grown Camptotheca acuminata seedlings in response to fertilization, variation in plant density, and cokppicing. The relationship between CPT and growth, and abscisic acid (ABA) levels were also examined. Fertilization caused positive responses in growth of both the slow- and the fast-growing C. acuminata plants. It lowered stomatal conductance ( g ), reduced leaf CPT level in slow-growing but not fast-growing seedlings in mid-summer (July), and increased leaf ABA level in dense plantings in early fall (September). Shoots induced to develop as a result of cokppicing were significantly higher in leaf CPT level than the original non-cokppiced shoots. These results suggest that in the C. acuminata plantation management, cokppicing should be employed to produce high concentrations of CPT, but that soil fertilization should be used cautiously so that greater growth is not achieved at the cost of lower CPT biosynthesis.