Syntheses of Jasmonic Acid Related Compounds and Their Structure-Activity Relationships on the Growth of Rice Seedings

Jasmonic acid (JA)-related compounds were synthesized, and their inhibitory activities on rice seedling growth were investigated. Three functions (C-1 CH₂COOH or CH₂COOCH₃, C-2 (Z)-2′-pentenyl or n-pentyl and C-3 ketone or hydroxyl) were essential for exhibiting inhibitory activity in this series of compounds. A dihydro-JA-related compound, 4-acetyl-nonanoic acid, also showed inhibitory activity similar to JA.     

Synthesis of Novel Plant Growth Inhibitors Structurally Related to Abscisic Acid

When paraffin wax is dispersed in medium as emulsion, some kinds of bacteria and yeasts readily grow on it. This paper presents a study on microbial cell production from solid paraffin. In this study a paraffin wax which contains 91% of normal paraffins ranging from C₂₅ to C₃₇ with the melting point of 62.5°C was used as a substate, but no solvent was used for the dispersion of the wax.

As a result of this study, the following have been found out. (1) Many strains of liquid normal paraffin assimilating bacteria and yeasts can assimilate paraffin wax. (2) Dried cell yields on added hydrocarbons of Corynebacterium hydrocarboclastus S-12-B2 and Candida tropicalis S-315-Y1 are 70% and 56% respectively, when they are cultured by wax emulsion of 0.6% concentration. (3) When nonion surface-active agent (Plysurf A210G) was added as an emulsifing agent, highly concentrated wax emulsion was obtained, but the growth of microorganisms on it was slower. Further investigation is needed to obtain better strains of bacteria and yeasts and also to find out optimum culture conditions.     

Abscisic Acid Structure-Activity Relationships in Barley Aleurone Layers and Protoplasts (Biological Activity of Optically Active,Oxygenated Abscisic Acid Analogs)

Optically active forms of abscisic acid (ABA) and their oxygenated metabolites were tested for their biological activity by examining the effects of the compounds on the reversal of gibberellic acid-induced [alpha]-amylase activity in barley (Hordeum vulgare cv Himalaya) aleurone layers and the induction of gene expression in barley aleurone protoplasts transformed with a chimeric construct containing the promoter region of an albumin storage protein gene. Promotion of the albumin storage protein gene response had a more strict stereochemical requirement for elicitation of an ABA response than inhibition of [alpha]-amylase gene expression. The naturally occurring stereoisomer of ABA and its metabolites were more effective at eliciting an ABA-like response. ABA showed the highest activity, followed by 7[prime]-hydroxyABA, with phaseic acid being the least active. Racemic 8[prime]-hydroxy-2[prime],3[prime]-dihydroABA, an analog of 8[prime]-hydroxyABA, was inactive, whereas racemic 2[prime],3[prime]-dihydroABA was as effective as ABA. The differences in response of the same tissue to the ABA enantiomers lead us to conclude that there exists more than one type of ABA receptor and/or multiple signal transduction pathways in barley aleurone tissue.     

枇杷蜜中脱落酸、多酚的测定及其指纹图谱的研究

以我国不同产地的10种枇杷蜜中的脱落酸及没食子酸、原儿茶酸、p-香豆酸、阿魏酸、芦丁、柚皮素、山奈酚等13种酚类物质为检测对象,利用高效液相色谱-二极管阵列检测技术(HPLC-DAD)进行检测。采用Welch XtimateTMC18柱(250 mm×4.6 mm,5μm)分离,以5%甲酸水及甲醇为流动相进行梯度洗脱,50 min内能较好地分离14种目标成分。利用中药色谱指纹图谱相似度评价系统(2004A版)对所得的图谱数据进行相似度分析,制定枇杷蜜的标准指纹图谱。同时利用掺入不同含量油菜蜜的枇杷蜜图谱数据对标准指纹图谱进行了验证。结果表明,14种目标成分在各自浓度范围内相关性良好(r=0.9990～0.9999);不同品牌枇杷蜜总酚物质分布不同(从263.4μg/100 g到580.3μg/100 g蜂蜜),其中总酚酸含量平均为249.3μg/100 g蜂蜜,显著高于总黄酮的含量(平均为140.9μg/100 g);14种成分在枇杷蜜中的分布不同,其中芦丁、脱落酸、α-儿茶酸含量最高,三者占总物质含量的68.9%;相似度的对比分析可以成功区分出不同程度的枇杷蜜掺假。本研究结果适合枇杷蜜中脱落酸及酚类物质的快速分离检测,制定的枇杷蜜标准指纹图谱可以有效用于单花蜜的品种鉴别及掺假检测,对于枇杷蜜的功能性分析及质量控制有重要的借鉴。     

Inhibition of Zinc Metallopeptidases by Flavonoids and Related Phenolic Compounds: Structure-Activity Relationships

Abstract

Flavonoids and other benzopyrone substances, having an appropriate hydroxylation profile, may inhibit the metalloenzymes leucine aminopeptidase (LAP), aminopeptidase M (AP-M), and carboxypeptidase A (CP-A). A structural feature that evidently favours the interaction between flavonoids and the three metalloenzymes is the 2,3-double bond conjugating the A and B rings and conferring a planar structure. This can be considered virtually indispensable for inhibition of the three metallopeptidases, though the hydroxylation profile required differed for each of the enzymes, and the interaction mechanism and behaviour also differed. The inhibitory effect of flavonoids on LAP was reversible, and to be effective the flavonoid had to have conjugated A and B rings and or tho-dihydroxylation on at least one of the aromatic rings. This same requirement was essential for inhibition by coumarins and was attributed to a catechol-like mechanism of interaction. The inhibitory effects on AP-M were due to inactivation of the enzyme, irreversibly altered by flavonoids with a 2,3-double bond and a minimum of one hydroxyl substituent on each of the aromatic rings. With CP-A, conjugation of the A and B rings enhanced the inhibitory effect of flavonoids, though it was not strictly required. The interaction between the polyphenolic substances tested and the two zinc aminopeptidases was not reversed by adding zinc to the reaction medium, indicating that the inhibition is not due to the coordination of the phenolic hydroxyl groups with the catalytical zinc of active site, though the presence of zinc affected the interaction behaviour differently according to each substance's hydroxylation profile.     

Syntheses and Biological Activities of New Plant Growth Inhibitors Structurally Related to Abscisic Acid

Several analogs of abscisic acid (ABA) were prepared and their biological activities were assayed. Among the compounds tested, 5-(l, 2-epoxy-2, 6, 6-trimethyl-l-cyclohexyl)-, 5-(l-hydroxy-2, 6, 6-trimethyl-2-cyclohexen-l-yl)- and 5-(l-hydroxy-2-methylene-6, 6-dimethyl-l-cyclohexyl)-3-methyl-cis, trans-2, 4-pentadienoic esters (V, IX, XXIII and XXV) were found to be potent plant growth inhibitors. Their activities were superior or comparable to that of ABA.     

Chemistry of Abscisic Acid, Abscisic Acid Catabolites and Analogs

Recently there have been breakthroughs on a number of fronts in abscisic acid (ABA) biology research that have advanced the field significantly, including discovery of genes involved in ABA metabolism, along with progress in understanding of ABA signaling (Finkelstein and others 2002; Kushiro and others 2004; Lim and others 2005; Saito and others 2004). At the same time, the chemistry of ABA has advanced. New analytical methods have been developed for profiling ABA and catabolites (Ross and others 2004; Zaharia and others 2005). Novel bioactive catabolites have been discovered from feeding studies with deuterated ABA and catabolites (Zaharia and others 2004; Zhou and others 2004). This review covers recent advances and prospects in natural products chemistry, analysis of ABA catabolism, and applications of ABA analogs for biochemical studies and horticultural uses.     

The Structure-Activity Relationships in Coronatine Analogs and Amino Compounds Derived from (+)-Coronafacic Acid

In order to investigate the active site of coronatine, the coronatine stereoisomers and analogs were synthesized by replacing the coronamic acid moiety with other amino compounds. The hypertrophy response of potato tubers was used for the bioassay of the compounds. A carboxyl group in coronamic acid was indispensable for the induction of activity. Moreover, the configuration at α-carbon atom in the amino acid was closely related to increase in activity Some alkyl groups of the amino acid also concerned with the activity.     

对氨基二苯醚类化合物与细胞色素P450相互作用的定量与活性关系

对氨基二苯醚类化合物是结构色素Ｐ４５０（Ｐ４５０）的一种准不可逆抑制剂。本文测定了１７种这类化合物生成Ｐ４５０代谢中间体络合物的活性和抑制Ｐ４５０催化氧化氨基比林脱甲基的活性。用逐步多元回归分析法导出了这两种活性与Ｈａｎｓｃｈ理化参数或分子轨道指数之间的定量结构与活性关系（ＱＳＡＲ）。结果表明：这两种活性都与取代基的脂溶性参数之（Σπ）和间位的立体性参数Ｅｓ（３′）等Ｈａｎｓｃｈ理化参数或最低未占据分子轨道级（ＥＬＵＭＯ）和原子净电荷的绝对值之和（ΣＱ）等分子轨道指数相关;生成Ｐ４５０代谢中间体络合物的活性还与取代基的电性参数之和（Σσ）和邻位和立体性参数（Ｅｓ（２′）相关。两种活性之间存在很好的相关性。     

植物ABA受体及其介导的信号转导通路

ABA是调控植物体生长发育和响应外界应激的重要植物激素之一。近年来, ABA受体的筛选和鉴定取得了突破性进展, 为植物中ABA信号转导通路的阐明奠定了重要基础。该文主要综述了ABA-binding protein/H subunit of Mgchelatase (ABAR/CHLH)、G protein-coupled receptor 2 (GCR2)、GPCR-type G protein 1/2 (GTG1/2)和pyrabactin resistant/PYR-like/regulatory component of ABA (PYR/PYL/RCAR)被报道为ABA受体的研究历程, 重点介绍了以ABAR/CHLH PYR/PYL/RCAR为受体的ABA信号转导通路模型的构建, 旨在为ABA受体及其信号转导通路的相关研究提供参考。     

Abscisic Acid in relation to mineral deprivation

Tobacco (Nicotiana rustica) plants growing in half-strength Hoagland solution were deprived of nutrients by being transferred to distilled water. The abscisic acid content of leaves in the mineral-deprived plants rose continuously throughout the 7 days of the experimental period. However, although the content of ABA rose within 24 hours, a decline in growth and leaf-chlorophyll were discernible only after the 4th day of mineral deprivation. As anticipated, mineral-deprived (stressed) plants exhibit “resistance” to lack of aeration in the root medium, similar to that shown in salt-stressed plants or plants that were pretreated with absiscic acid. When the mineral-deprived plants were returned to half-strength Hoagland, the content of leaf abscisic acid declined to the prestressed level and the “resistance” to lack of root aeration disappeared.     

Studies on Abscisic Acid

Methyl α-cyclocitrylideneacetate was successively oxidized with selenium dioxide and chromium trioxide-pyridine complex to give methyl 1′-hydroxy-α-cyclocitrylideneacetate and a mixture of methyl 3′-keto-β-cyclocitrylideneacetate and methyl 4′-keto-α-cyclocitrylideneacetate. Further, oxidation of methyl α-cyclocitrylideneacetate with tert-butyl chromate afforded methyl 4′-keto-α-cyclocitrylideneacetate and methyl 1′-hydroxy-4′-keto-α-cyclocitry-lineacetate. Similarly, methyl α-cyclogeranate was oxidized to methyl 3-keto-β-cyclogeranate and methyl 4-keto-α-cyclogeranate. Methyl l′-hydroxy-4′-keto-α-cyclocitrylideneacetate, methyl l-hydroxy-4-keto-α-cyclogeranate and their related compounds did not show growth inhibitory activities on rice seedlings.     

Studies on Abscisic Acid

Epoxidation of methyl dehydro-β-ionylideneacetates with perbenzoic acid afforded methyl 1′, 2′-epoxy-dehydro-β-ionylideneacetates and then methyl 1′, 2′-, 3′, 4′-di-epoxy-dehydro-β-ionylideneacetates. 1′,2′-Epoxy-dehydro-β-ionone, obtained byepoxidation of dehydro-β-ionone, was treated with carbethoxymethylenetriphenlphosphorane to give ethyl 1′, 2′-epoxy-dehydro-β-ionylideneacetates. Further, sensitive photooxidation of ethyl dehydro-β-ionylidenecrotonate, followed by alkaline hydrolysis, gave 1′-hydroxy-4′-keto-α-ionylidenecrotonic acid. Growth inhibitory activities of the above compounds on rice seedlings were examined.     

Studies on Abscisic Acid

Oxidation of 2-cis-α-ionylidene-ethanol (II) with active MnO₂ afforded a mixture of 2-cis and 2-trans-α-ionylideneacetaldehydes (III and IV). Reduction of methyl epoxy-α- and -β-ionylideneacetates (Vb, Xb XXIb and XXIIb) with LiAlH₄ gave the diols (VI, XI, XXIII and XXIV). The Wittig reaction of the hydroxyketones (XIII and XVIII) with carbethoxymethylenetriphenylphosphorane, followed by alkaline hydrolysis, yielded 5-(1′-and 2′-hydroxy-2′,6′,6′-trimethyl-1′-cyclohexyl)-3-methylpentadienoic acids (XIVa, XVa, XIXa and XXa). The reaction of α-cyclocitrylideneacetaldehyde (XXVII) and dihydro-α-ionone (XXXIII) with carbethoxymethylenetriphenylphosphorane afforded ethyl 3-demethyl-α-ionyli-deneacetate (XXVIIIb) and ethyl dihydro-α-ionylideneacetates (XXXIVb and XXXVb). Physiological activities of the above synthesized compounds on rice seedlings were examined.     

Studies on Abscisic Acid

Methyl α-ionylideneacetates were oxidized with selenium dioxide to a mixture of methyl 3′-keto-β-ionylideneacetates and a small amount of methyl 4′-keto-α-ionylidene-acetates followed by treatment with active manganese dioxide. By a similar oxidation methyl 3′-keto-β-ionylideneacetates were prepared from methyl β-ionylidene acetates. Methyl 4′-keto-α-ionylideneacetates were obtained by oxidation of methyl α-ionylideneacetates with tert-butyl chromate. Dehydrobromination of methyl bromoionylideneacetate, obtained by bromination of methyl 2-trans-α-ionylideneacetate with N-bromosuccinimide, gave a mixture of methyl 2-trans-dehydro-β-ionylideneacetate and methyl 2-cis-dehydro-β-ionylideneacetate. The growth inhibitory activities of these sesquiterpene carboxylic acids and keto esters on rice seedlings were tested.     

Studies on Abscisic Acid

Photosensitized oxygenation of dehydro-β-ionylidene-ethanol afforded 1′-hydroxy-4′keto-α-ionylidene-ethanol, which was oxidized with active MnO₂ to give 1′-hydroxy-4′-keto-α-ionylidene-acetaldehyde. The Wittig reaction of α-ionylideneacetaldehyde with carbethoxymethylenetriphenylphosphorane or the phosphorane prepared from ethyl γ-bromosenecioate gave ethyl α-ionylidene-crotonate or ethyl α-ionylidenesenecioate. Vitamin A₂ acid ethyl ester was converted to the hydroxy-keto-ester by photosensitized oxygenation. About the above synthesized compounds were examined growth inhibitory activities on rice seedlings.     

Studies on Abscisic Acid

Oxidation of methvl 2-trans-β-ionylideneacetate with X-bromosuccinimide afforded methyl 2-cis and trans-3′-hydroxy-β-ionylideneacetates. NaBH₄ reduction of methyl 2-cis-3′-keto-β-ionylideneacetate and ethyl 4′-keto-α-ionylideneacetate gave methyl 2-cis-3′-hydroxy-β-ionylideneacetate and ethyl 4′-hydroxy-α-ionyiideneacetate respectively. Further, methyl 4′-methoxy-epoxy-α-ionylideneacetate was prepared by epoxidation of methyl 4′-methoxy-α-ionylideneacetate. And then methyl 4′-hydroxy-l′, 2′-dihydro-β-ionylideneacetate was synthesized from ethyl 4-keto-α-cyclogeranate. Growth inhibitory activities of the above compounds on rich seedlings were examined.     

The Abscisic Acid Content of Citrus with Special Reference to Lemon

Free and conjugated abscisic acid (ABA) in the fruit peel offour species of citrus and their distribution in the variousreproductive organs of Citrus limon L. cv. Eureka during ontogenywere determined by an indirect enzyme-linked immunosorbent assay(ELISA). The different citrus species varied in free ABA (3-8g g dry wt.) and conjugated ABA (10-39 /xg gl dry wt.). In general,the amount of conjugated ABA was 4-fold that of free ABA. Inthe lemon flower, the combined style and stigma tissues containedthe predominant (>65%) amount of both free and conjugatedABA. During fruit development, free and conjugated ABA of thedifferent tissues showed dynamic changes. In the vesicles, freeABA showed progressive increases with development and reacheda high level at maturity whereas the conjugated ABA showed acorresponding decrease with fruit development. Free ABA in theseed increased with fruit development. The content of ABA incitrus fruit was significantly correlated ( = 8.06 + 2.81 Inx; /-2 = 0.84^**) with the weight of the fruit Key words: Abscisic acid, citrus species, reproductive organs, development     

Abscisic Acid Translocation and Influence of Water Stress on Grain Abscisic Acid Content

The movement of foliar applied [1-¹⁴C]abscisic acid (ABA) inwheat plants (Triticum aestivum L., cv. Kolibri) was investigatedat two stages of grain development (1000 grains, weight 19 and24 g dry matter). [1–¹⁴C]ABA seemed to be readily translocated within 12h into the developing grains as well as in other plant parts.A subsequent rapid metabolism took place leading to a decreasedactivity of the ABA-containing chromatogram fraction in theyounger plants 48 h after application. The metabolism seemodto be less intensive in the older grains, where the activityrunning with the ABA increased over 64 h. Treating the leaves of barley plants (Hordeum vulgare, L., cv.Union) 2 weeks after anthesis with a gentle stream of warm air(36° C) resulted in a significant increase in the ABA contentof all parts of the ear. The results mentioned above indicatethat this may be partially due to translocation from other partsof the plant such as the leaves.