Plant Polyprenols and Their Biological Activity

Research on the isolation, identification, and biological activity of plant polyprenols is reviewed.     

Screening of Humic Substances Extracted from Leonardite for Free Radical Scavenging Activity Using DPPH Method

Humic substances (HSs) have been researched for a long time and still manage to surprise humanity today. According to the latest research, in addition to their previously well-known effects, they also have antioxidant properties. However, this previous research does not examine the difference in the antioxidant effect of the fractions extracted/produced in different processes; they do not consider the light absorption of the HSs, which falsifies analysis based on the measurement of color change over time. In the present work, HS fractions were obtained from leonardite, the extraction processes can also be implemented on an industrial scale. The fractions were characterized by elementary analysis, UV–Vis and FT-IR spectroscopies, to prove that our self-extracted samples have similar characteristics to the International Humic Substances Society (IHSS) standard samples. The different methods of HS fractionation affected the elemental composition, and the spectral characteristics. The antioxidant effect was investigated using the DPPH method to screen the antioxidant efficiency of humic, fulvic, and himatomelanic acids. In addition, we compared our results with the IHSS standard samples to obtain a more comprehensive picture of the antioxidant effect of HSs extracted in different ways according to the DPPH method. Based on our results, the extraction method affects not only the physico-chemical properties but also the free radical scavenging activity of the fractions.     

The Singular Molecular Conformation of Humic Acids in Solution Influences Their Ability to Enhance Root Hydraulic Conductivity and Plant Growth

Some studies have reported that the capacity of humic substances to improve plant growth is dependent on their ability to increase root hydraulic conductivity. It was proposed that this effect is directly related to the structural conformation in solution of these substances. To study this hypothesis, the effects on root hydraulic conductivity and growth of cucumber plants of a sedimentary humic acid and two polymers—polyacrylic acid and polyethylene glycol—presenting a molecular conformation in water solution different from that of the humic acid have been studied. The results show that whereas the humic acid caused an increase in root hydraulic conductivity and plant growth, both the polyacrylic acid and the polyethylene glycol did not modify plant growth and caused a decrease in root hydraulic conductivity. These results can be explained by the different molecular conformation in water solution of the three molecular systems. The relationships between these biological effects and the molecular conformation of the three molecular systems in water solution are discussed.     

α-(1,3,4-噻二唑-5-基)氨基烃基膦酸酯的合成及生物活性

以5-氨基-2-巯基的席夫碱与亚磷酸二乙酯反应, 合成了15个新的α-(1,3,4-噻二唑-5-基)氨基烃基膦酸酯, 初步的生物活性测试表明部分目标化合物具有较好的植物生长调节活性, 其中2,4-二氯苯甲醛、呋喃甲醛和吲哚甲醛的席夫碱生成的α-氨基烃基膦酸酯具有较好的生长素活性.     

Synthesis of Lactosylated Piperazinyl Porphyrins and Their Biological Activity

The aim of this work is to synthesize of a new family of lactosylated piperazinly porphyrins, in which the galactoside piperazine moieties are linked to the tetra‐ and mono‐phenyl rings of tetraphenylporphyrin (TPP). 5,10,15,20‐Tetrakis[4‐(4‐lactobionylpiperazin‐1‐yl)phenyl]porphyrin (TLPP) and 5‐mono[4‐(4‐lactobionylpiperazin‐1‐yl)phenyl]‐10,15,20‐triphenylporphyrin (MLPP) have been synthesized. A detailed ¹H NMR study gave their complete structural elucidation. The UV‐Visible, mass spectra and elemental analysis are also presented. The biological activity on cancer cells and the pharmacokinetics have also been evaluated, showing a better biological activity, a very high liver to skin ratio and short retention time in tissues. It was suggested that such novel lactosylated piperazinly porphyrins, as potential hepatocyte‐selective targeting drugs, exhibit a promising activity in photodynamic therapy (PDT).     

不对称1,3,2—二氧磷杂环己烷非对映选择性合成及其生物活性

不对称１，３，２－二氧磷杂环己烷非对映选择性合成及其生物活性邵瑞链＊杨敏华成俊然（南开大学元素有机化学研究所，元素有机化学国家重点实验室天津３０００７１）关键词二氧磷杂环，立体有择合成，顺反异构体，生物活性１９９７－０６－０４收稿，１９９７－１２－０...     

含硅氨基甲酸酯衍生物的合成,结构及生物活性

通过１－甲硫基亚乙基氨－甲基氨基甲酸酯与二氯亚砜反应，制得一系列新的含硅氨基甲酸酯衍生物．化合物结构经１￣ＨＮＭＲ、元素分析ＩＲ和ＭＳ确证，测定了化合物３ａ的晶体结构．生物测定结果表明，该类化合物对蚊子、粘虫、玉米螟等多种害虫具有优良的杀虫活性，且与母体灭多威相比，在哺乳动物安全性方面有显著提高．     

N-5-(1H-1,2,4-三唑基）-N'-芳甲酰基脲的合成与生物活性

以5-氨基-1H-1，2，4-三唑-3-羧酸与酰基异氰酸酯反应，合成了15个新的N- 5-（1H-1，2，4-三唑基）-N'-芳甲酰基脲，用核磁共振氢谱、红外光谱和元素分 析确证了其结构，并进行了室内生物活性测试。生测试验证明部分酰基脲类化合物 具有良好的植物生长调节活性，其中N-5（3-羧基-1，2，4-三唑基）-N'-o-氯苯甲 酰基脲、N-5-（3-羧基-1，2，4-三唑基）-N'-o-溴苯甲酰基脲和N-5-(3-羧基-1， 2，4-三唑基）-N'-p(或m)-甲基苯甲酰基脲具有优良的生长素活性。     

Diversity in Chemical Structures and Biological Properties of Plant Alkaloids

Phytochemicals belonging to the group of alkaloids are signature specialized metabolites endowed with countless biological activities. Plants are armored with these naturally produced nitrogenous compounds to combat numerous challenging environmental stress conditions. Traditional and modern healthcare systems have harnessed the potential of these organic compounds for the treatment of many ailments. Various chemical entities (functional groups) attached to the central moiety are responsible for their diverse range of biological properties. The development of the characterization of these plant metabolites and the enzymes involved in their biosynthesis is of an utmost priority to deliver enhanced advantages in terms of biological properties and productivity. Further, the incorporation of whole/partial metabolic pathways in the heterologous system and/or the overexpression of biosynthetic steps in homologous systems have both become alternative and lucrative methods over chemical synthesis in recent times. Moreover, in-depth research on alkaloid biosynthetic pathways has revealed numerous chemical modifications that occur during alkaloidal conversions. These chemical reactions involve glycosylation, acylation, reduction, oxidation, and methylation steps, and they are usually responsible for conferring the biological activities possessed by alkaloids. In this review, we aim to discuss the alkaloidal group of plant specialized metabolites and their brief classification covering major categories. We also emphasize the diversity in the basic structures of plant alkaloids arising through enzymatically catalyzed structural modifications in certain plant species, as well as their emerging diverse biological activities. The role of alkaloids in plant defense and their mechanisms of action are also briefly discussed. Moreover, the commercial utilization of plant alkaloids in the marketplace displaying various applications has been enumerated.     

α-氨基膦酸及其酯的合成及生物活性的研究进展

α-氨基膦酸及其衍生物已成为国内外关注的热点.作为天然氨基酸的类似物,在医药、农药中起到越来越重要的作用,综述了有关2-氨基膦酸及其酯的合成、生物活性研究方面的工作,并对它的发展趋势、应用前景作了进一步的展望.     

N-(2-羧基-1,3,4-噻二唑-5-基)-N''-芳酰基硫脲与芳氧乙酰基硫脲的合成与生物活性

为了寻找高活性的杂环农药,用5-氨基-1,3,4-噻二唑-2-羧酸与芳酰基异硫氰酸酯及芳氧乙酰基异硫氰酸酯反应,合成出18种新的芳酰基硫脲与芳氧乙酰基硫脲,采用红外光谱、核磁共振氢谱和元素分析证明了其结构,初步的生物活性测定试验表明,部分目标化合物具有良好的植物生长调节活性,其中2c,2d,3b和3g具有良好的生长素活性.     

N-(5-对三氟甲基苯基-1,3,4-噻二唑-2-基)-N''''-芳酰基硫脲的合成及生物活性

用2-氨基-5-对三氟甲基苯基1，3，4-噻二唑与芳酰基异硫氰酸酯反应，合成了14种新的标题化合物（3a-3n），其的结构经1^H NMR，IR和元素分析确证。室内初步的生物活性测定试验表明，部分标题化合物具有良好的植物生长调节活性，其中3e，3g和3m的生长素活性更好。     

N-(2-羧基-1,3,4-噻二唑-5-基)-N'-芳酰基硫脲与芳氧乙酰基硫脲的合成与生物活性

为了寻找高活性的杂环农药, 用5-氨基-1,3,4-噻二唑-2-羧酸与芳酰基异硫氰酸酯及芳氧乙酰基异硫氰酸酯反应, 合成出18种新的芳酰基硫脲与芳氧乙酰基硫脲, 采用红外光谱、核磁共振氢谱和元素分析证明了其结构, 初步的生物活性测定试验表明, 部分目标化合物具有良好的植物生长调节活性, 其中2c, 2d, 3b和3g具有良好的生长素活性.     

盐酸-5-甲基-8-羟基喹啉的晶体结构与生物活性研究

5-甲基-8-羟基喹啉(1)经盐酸酸化成1.HC l,其水溶性增强。研究了1.HC l对蚕豆有丝分裂的影响,结果表明,1.HC l更能有效地促进细胞的有丝分裂。培养了单晶1.HC l。在293 K,用单晶X-射线衍射法对1.HC l进行了结构表征。1.HC l晶体属于单斜晶系,空间群P21/c,a=0.73770(9)nm,b=1.57126(19)nm,c=0.81414(10)nm,β=101.329(2),°V=0.9253(2)nm3,Z=4,Dc=1.404 g.cm-3,F(000)=408,μ=0.368 mm-1,R1=0.0393,wR2=0.1091。     

钒酰腙配合物的合成、结构及生物活性

以酰腙为配体钒的单核、双核配合物因其结构丰富、生物活性多样而引起广泛关注。目前该领域新配合物的合成、表征和生物活性的研究甚为活跃。本文回顾了近年来钒酰腙配合物的研究状况,主要从以下三个方面进行综述：(1)钒酰腙配合物的合成方法;(2)此类配合物的配位模式;(3)一些单、双核钒酰腙配合物抗变形虫,抗肿瘤,类胰岛素,抑制Na⁺, K⁺-ATP酶,与DNA作用的生物活性。文中着重阐述了钒酰腙化合物的结构和生物活性之间的关系。此外,还提出了钒酰腙配合物研究领域的不足之处并对其今后发展方向进行了展望。     

Biological Activity of Essential Oils of Four Juniper Species and Their Potential as Biopesticides

The objective of this study was to assess the biological activity of essential oils (EOs) of four Juniperus species obtained via two different distillation methods and their potential as biopesticides. The studied factors were juniper species (Juniperus communis L., J. oxycedrus L., J. pygmaea C. Koch., and J. sibirica Burgsd), plant sex (male (M) and female (F)), and distillation method (hydrodistillation via a standard Clevenger apparatus (ClevA) and semi-commercial (SCom) steam distillation). The hypothesis was that the EO will have differential antioxidant, antimicrobial, and insecticidal activities as a function of plant species, plant sex, and distillation method. The two distillation methods resulted in similar EO composition within a given species. However, there were differences in the EO content (yield) due to the sex of the plant, and also differences in the proportions of some EO components. The concentration of α-pinene, β-caryophyllene, δ-cadinene and δ-cadinol was dissimilar between the EO of M and F plants within all four species. Additionally, M and F plants of J. pygmaea, and J. sibirica had significantly different concentrations of sabinene within the respective species. The EOs obtained via ClevA extraction showed higher antioxidant capacity within a species compared with those from SCom extraction. All of the tested EOs had significant repellent and insecticidal activity against the two aphid species Rhopalosiphum padi (bird cherry-oat aphid) and Sitobion avenae (English grain aphid) at concentrations of the EO in the solution of 1%, 2.5%, and 5%. The tested EOs demonstrated moderate activity against selected pathogens Fusarium spp., Botrytis cinerea, Colletotrichum spp., Rhizoctonia solani and Cylindrocarpon pauciseptatum. The results demonstrate that the standard ClevA would provide comparable EO content and composition in comparison with SCom steam distillation; however, even slight differences in the EO composition may translate into differential bioactivity.     

新型金属卟啉的合成及其仿酶活性研究

合成并表征了一系列水溶性和非水溶性金属卟啉3a～3e,5a～5f和8a～8f;测试了这些金属卟啉作为超氧化物歧化酶(SOD)和过氧化氢酶(CAT)的模拟物催化歧化O₂-和催化分解H₂O₂等有毒氧自由基的活性及抗脂质过氧化性质.结果表明,含有吡啶溴化盐的水溶性金属卟啉8a～8f的仿酶活性明显大于含有羟基的非水溶性金属卟啉3a～3e和含有酯基的金属卟啉5a～5f.     

Insights on Molecular Characteristics of Hydrochars by 13C-NMR and Off-Line TMAH-GC/MS and Assessment of Their Potential Use as Plant Growth Promoters

Hydrochar is a carbon-based material that can be used as soil amendment. Since the physical-chemical properties of hydrochar are mainly assigned to process parameters, we aimed at evaluating the organic fraction of different hydrochars through ¹³C-NMR and off-line TMAH-GC/MS. Four hydrochars produced with sugarcane bagasse, vinasse and sulfuric or phosphoric acids were analyzed to elucidate the main molecular features. Germination and initial growth of maize seedlings were assessed using hydrochar water-soluble fraction to evaluate their potential use as growth promoters. The hydrochars prepared with phosphoric acid showed larger amounts of bioavailable lignin-derived structures. Although no differences were shown about the percentage of maize seeds germination, the hydrochar produced with phosphoric acid promoted a better seedling growth. For this sample, the greatest relative percentage of benzene derivatives and phenolic compounds were associated to hormone-like effects, responsible for stimulating shoot and root elongation. The reactions parameters proved to be determinant for the organic composition of hydrochar, exerting a strict influence on molecular features and plant growth response.     

N-[5-(1-邻(对)氯苯氧乙基)-1,3,4-噻二唑-2-基]-N'-芳酰基硫脲的合成与生物活性

为了寻找高活性的杂环农药, 通过2-氨基-5-(1-邻氯苯氧乙基)-1,3,4-噻二唑和2-氨基-5-(1-对氯苯氧乙基)-1,3,4-噻二唑与芳酰基异硫氰酸酯反应, 合成了26种新的芳酰基硫脲. 采用核磁共振氢谱、红外光谱及元素分析确证了它们的结构. 初步的生物活性测定试验表明, 部分目标化合物表现出良好的植物生长调节活性, 其中3c, 3d, 3e, 4b和4c具有优良的生长素活性.     

Synthesis,Characterization, and Biological Activity of Substituted Thiazole-5-carboxaldehydes and Their Ylidenenitriles Derivatives

The Vilsmeier–Haack reaction of 2-amino -4-(4-substituted phenyl)-thiazoles 1, in the presence of micellar media, gives formylated derivatives 2, which upon hydrolysis afforded thiazole-5-carboxaldehydes 3. Microwave-assisted Knoevenagel condensation of 3 with active methylene compounds, in the presence of piperidine as catalyst, gives excellent yields of ylidenenitrile compounds 4. The structures of the newly synthesized compounds were established on the basis of elemental analysis, IR, ¹H NMR, and ¹³C NMR spectral analysis. All newly synthesized compounds were screened for antibacterial activity using two Gram-positive and one Gram-negative bacterial species and their antifungal activity was screened using two fungal species.