PsCor413pm2, a Plasma Membrane-Localized, Cold-Regulated Protein from Phlox subulata, Confers Low Temperature Tolerance in Arabidopsis.

Low temperature stress adversely affects plant growth and development. Isolation and characterization of cold response genes from cold-tolerant plants help to understand the mechanism underlying low temperature tolerance. In this study, PsCor413pm2, a cold-regulated (COR) gene isolated from Phlox subulata, was transferred to Arabidopsis plants to investigate its function. Real-time quantitative PCR analysis revealed that PsCor413pm2 expression was induced by cold. Subcellular localization revealed that the PsCor413pm2-green fluorescent protein (GFP) fusion protein localized to the plasma membrane in tobacco and Arabidopsis plants. Furthermore, overexpression of PsCor413pm2 in Arabidopsis plants enhanced tolerance to low temperature stress. Transgenic Arabidopsis roots had more influx of Ca2+ after a cold shock than wild-type plants, as shown using non-invasive micro-test technology (NMT). Moreover, the transcription abundance of five COR and two C-repeat (CRT) binding factor (CBF) genes in transgenic Arabidopsis plants was higher than that in the wild-type plants under cold stress. Taken together, our results suggest that overexpression of PsCor413pm2 enhances low temperature tolerance in Arabidopsis plants by affecting Ca2+ flux and the expression of stress-related COR and CBF genes.

Gallic acid as the major antioxidant in pequi (Caryocar brasiliense Camb. ) fruit peel / Ácido gálico como principal antioxidante da casca do fruto do pequi (Caryocar brasiliense Camb. )

ABSTRACTIn this study, ethanol-water extracts of pequi fruit peel were fractionated in order to identify and quantify the major antioxidant present in it. The fractions were subjected to liquid-liquid phase extraction and silica-gel column chromatography, and antioxidant activity was monitored using the 2,2-diphenyl-1-picrylhydrazyl radical-scavenging assay. The purity of the fractions was evaluated using thin-layer chromatography and high-performance liquid chromatography (HPLC). The substance with antioxidant property was identified through the analysis in a liquid chromatography-mass spectroscopy fragmentation and was quantified using HPLC. After the Silica-gel fractionation, it was identified a fraction with high antioxidant activity and purity, which contained gallic acid as the main compound. The gallic acid was found at the amount of 26.54 ± 1.13 mg/g of the dry mass of the pequi fruit peel. Because the quantifications were performed using crude ethanol-water extract, it was suspected that gallic acid was present in a free form. Thus, pequi fruit peel may serve as an attractive alternative of feedstock for natural antioxidant production. Moreover, the results obtained in this study emphasize the value of the pequi plant, and suggests improved opportunities for families that use this fruit`s products.

RESUMOExtratos hidroetanólicos da casca do fruto do pequi foram fracionados a fim de identificar e quantificar o principal antioxidante presente. Frações do extrato foram submetidas ao particionamento líquido-líquido e fracionamento em coluna de sílica gel. As atividades antioxidantes das frações foram monitoradas usando ensaio de redução do radical 2,2-difenil-1-picrilhidrazila e a pureza das frações foi avaliada em cromatografia de camada delgada e cromatografia líquida de alta eficiência (CLAE). A substância com propriedades antioxidantes foi identificada através da análise em sistema de cromatografia líquida associada à espectrometria de massas e foi quantificada em HPLC. Após o fracionamento identificou-se uma fração com alta atividade antioxidante e pureza, contendo ácido gálico como o composto principal. Ácido gálico foi encontrado em concentrações de 26,54 ± 1,13 mg/g de massa seca. Devido às quantificações terem sido realizadas no extrato hidroetanólico bruto, acredita-se que o ácido gálico esteja presente na forma livre. Assim, a casca do fruto pequi pode servir como interessante alternativa de matéria prima para a produção desse antioxidante natural. Além disso, esse resultado enfatiza o valor da planta do pequi e sugere oportunidades para as famílias que utilizam produtos de pequi.

The phytochemistry and biological aspects of Caryocaraceae family / Aspectos fitoquímicos e biológicos da família Caryocaraceae

The Caryocaraceae family is constituted of 25 species distributed in two genera (Caryocar and Anthodiscus). Plants of this family have been used in several phytochemical studies for isolation and characterization of chemical compounds. Some of these studies evaluated in vitro and in vivo biological activities of extracts and pure substances isolated from plants of this family. Nine species of Anthodiscus genus have been described, while no phytochemical study related to them has been reported. On the other hand, Caryocar genus presents 16 species with several medicinal uses like for the treatment of colds and bronchitis, in the prevention of tumours, as a regulating agent of the menstrual flow, to treat ophthalmological problems and for the cure of hematomas and bruises. Some species of this genus were targeted by phytochemical studies and presented, in their composition, the following classes of secondary metabolites: triterpenes, fatty acids, tannins, carotenoids, triterpenic saponins, phenolic coumarins, phenolic glycosides, and others. The fruits of Caryocar species are very nutritive, containing in their composition fibers, proteins, carbohydrates and minerals. Seeds have been widely used as oil source with nutritional and cosmetic value. The biological evaluation of some species was carried out by using relevant biological assays such as: antioxidant, allelopathic and antifungal activities against Biomphalaria glabrata and toxicity on Artemia salina.

A família Caryocaraceae é constituída por 25 espécies distribuídas em dois gêneros (Caryocar e Anthodiscus). Plantas desta família têm sido utilizadas em diversos estudos fitoquímicos para isolamento e caracterização de constituintes químicos. Alguns destes estudos avaliaram atividades biológicas in vitro e in vivo de extratos e substâncias puras isoladas a partir de plantas desta família. São descritas nove espécies dentro do gênero Anthodiscus e nenhum estudo fitoquímico relacionado a elas foi relatado. Por outro lado, o gênero Caryocar apresenta 16 espécies com diversos usos medicinais, tais como: para o tratamento de resfriados, bronquites, na prevenção de tumores, como reguladores do fluxo menstrual, em problemas oftalmológicos, e na cura de hematomas e contusões. Algumas espécies deste gênero foram submetidas a estudos fitoquímicos e apresentaram, em sua composição, as seguintes classes de metabólitos secundários: triterpenos, ácidos graxos, taninos, carotenoides, saponinas triterpênicas, cumarinas, glicosídeos fenólicos, entre outros. Os frutos de espécies Caryocar são muito nutritivos contendo em sua composição, fibras, proteínas, carboidratos e minerais. As sementes têm sido amplamente usadas como fonte de óleo com valor nutricional e cosmético. A avaliação biológica de algumas espécies foi realizada utilizando-se testes biológicos relevantes, entre eles: a atividade antioxidante, alelopática, antifúngica, contra Biomphalaria glabrata, e toxicidade sobre Artemia salina.

Optimisation of the azinobis-3-ethyl-benzothiazoline-6-sulphonic acid radical scavenging assay for physiological studies of total antioxidant activity in woody plant germplasm.

A robust spectroscopic method for determining total antioxidant activity in aqueous extractions has been applied to tissues from diverse woody plant species, including seeds of Coffea arabica and in vitro shoots from Ribes nigrum, Picea sitchensis and Shorea leprosula. The assay involves scavenging of an ABTS [2,2'-azinobis-(3-ethyl-benzothiazoline-6-sulphonic acid)] radical generated by the reaction of potassium persulphate with ABTS to produce an ABTS*(+) chromophore (lambda=734 nm). Antioxidants reduce ABTS*(+) back to ABTS with a concomitant decrease in absorbance. Aqueous extractions from C. arabica and S. leprosula had considerably higher (110-205 micromol Trolox eq. g(-1) FW) total antioxidant activities than P. sitchensis and R. nigrum (6-11 micromol Trolox eq. g(-1) FW). Further studies in two of these species showed that the inclusion of water-insoluble polyvinylpyrrolidone during aqueous tissue extraction enabled the combined phenolic and alkaloid antioxidant activity to be determined. These fractions accounted for 85% and 60% of total antioxidant activity for C. arabica seeds and R. nigrum shoots, respectively. The ABTS radical scavenging assay is presented herein as a robust method for determining total antioxidant activity in germplasm from diverse woody plant tissues and species. Its applicability to study oxidative stress in tissue cultures and germplasm employed in plant biotechnology, breeding and stress physiology programmes is discussed.

Changes in photosynthesis and leaf characteristics with tree height in five dipterocarp species in a tropical rain forest.

Variations in leaf photosynthetic, morphological and biochemical properties with increasing plant height from seedlings to emergent trees were investigated in five dipterocarp species in a Malaysian tropical rain forest. Canopy openness increased significantly with tree height. Photosynthetic properties, such as photosynthetic capacity at light saturation, light compensation point, maximum rate of carboxylation and maximum rate of photosynthetic electron transport, all increased significantly with tree height. Leaf morphological and biochemical traits, such as leaf mass per area, palisade layer thickness, nitrogen concentration per unit area, chlorophyll concentration per unit dry mass and chlorophyll to nitrogen ratio, also changed significantly with tree height. Leaf properties had simple and significant relationships with tree height, with few intra- and interspecies differences. Our results therefore suggest that the photosynthetic capacity of dipterocarp trees depends on tree height, and that the trees adapt to the light environment by adjusting their leaf morphological and biochemical properties. These results should aid in developing models that can accurately estimate carbon dioxide flux and biomass production in tropical rain forests.

Allocation to defense or growth in dipterocarp forest seedlings in Borneo.

We quantified the allocation of net production to plant secondary metabolites (especially condensed tannins and lignins) to evaluate the investment into defense mechanisms of three tropical forest canopy species in Borneo vis-à-vis the resource availability hypothesis. In particular, we focused on Borneo ironwood (Eusideroxylon zwageri, Lauraceae), which seemed to employ an extreme defensive strategy. The wood of this species is extremely durable and has a high specific gravity with a very slow growth rate. The allocation to defense by Borneo ironwood was compared to two emergent species of Dipterocarpaceae, the dominant family in this forest community. We conducted shade-house experiments on seedlings under four controlled conditions (two light levels x two nutrient levels) and showed that the growth rate of E. zwageri was much lower than those of the other two species, and it allocated more of its net production to leaves and roots than to stems. The concentrations of condensed tannins and lignins were very high in the leaves and stems of this species, at about 20 and 30%, respectively. In total, E. zwageri allocated a maximum of about 35% of its net production to defensive substances (i.e., condensed tannins + lignins). In contrast, the two dipterocarp species allocated about 20-25% of their net production to defensive substances. The condensed tannins in E. zwageri help to prolong the lifespan of the leaves, and the lignins in the stems enhance the durability of the wood. Thus, although E. zwageri grows very slowly, the allocation to defensive substances seems to be an advantageous strategy for survival under dark conditions.

Neuroendocrine evidence for dopaminergic actions of hypericum extract (LI 160) in healthy volunteers.

BACKGROUND: We studied the effect of a single dose of a formulation of a methanolic extract of Hypericum perforatum (HP), also known as St. John's wort, on plasma concentrations of growth hormone (GH), prolactin (PRL), and cortisol (CORT) in 12 healthy male volunteers. METHODS: Subjects received 9 tablets of the finished product Jarsin 300 and placebo in a double-blind, balanced-order, cross-over design. RESULTS: Following HP relative to placebo, there was a significant increase in plasma GH and a significant decrease in plasma PRL. Plasma CORT levels were unchanged. CONCLUSIONS: Taken together with data from animal experimental studies, the findings suggest that this dose of HP may increase some aspects of brain dopamine function in humans.

Oxidation products of hyperforin from Hypericum perforatum.

The isolation of two oxidation products of hyperforin from the aerial parts of Hypericum perforatum and their structure determination by means of 2D NMR methods is reported. The products had the same 1-(2-methyl-1-oxopropyl)-2,12-dioxo-3,10 beta-bis(3-methyl-2-butenyl)-11 beta-methyl-11 alpha-(4-methyl-3-pentenyl)-5-oxatricyclo[6.3.1.0(4,8)]-3-dodec ene skeleton. In addition, one of them, with the same number of carbons as hyperforin (C35H52O5), contained a 1-methyl-l-hydroxyethyl group in the 6 beta-position, whereas the other compound (a hemiacetal, C32H46O5), presumably a degradation product of hyperforin, exhibited a 6-hydroxy function. The latter was an inseparable mixture of 6 alpha- and 6 beta-hydroxy epimers undergoing (according to phase sensitive NOESY) mutual interconversion.

Xanthones from Hypericum japonicum and H. henryi.

From the aerial part of Hypericum japonicum, one new xanthone glycoside, 1,5-dihydroxyxanthone-6-O-beta-D-glucoside, one novel dimer xanthone, bijaponicaxanthone, and the first natural prenylated xanthone, 1,3,5,6-tetrahydroxy-4-prenylxanthone, were isolated together with the four known xanthones, 1,5,6-trihydroxyxanthone, isojacereubin, 6-deoxyisojacareubin and 4',5'-dihydro-1,5,6-trihydroxy-4',4',5'-trimethylfurano (2',3':4,5) xanthone. five previously known xanthones, kielcorin, cadensin, 1,7,-dihydroxyxanthone, 1,5-dihydroxy-4-methoxyxanthone and 1,2,5-trihydroxyxanthone were also found in the dichoromethane extract of the stems and leaves of H. henryi. Their structures were elucidated by spectroscopic and chemical methods. Some of the compounds from H. japonicum were found to exert an interesting coagulant activity in an in vitro test. The chemotaxonomic value of xanthones is discussed briefly.