Relevance of carnosic acid concentrations to the selection of rosemary, Rosmarinus officinalis (L.), accessions for optimization of antioxidant yield

Methods were developed to identify and select accessions of rosemary, Rosmarinus officinalis (L.), producing optimum antioxidant activity. Extracts from 12 different rosemary accessions, using three solvents of varying polarity, were assayed for their antioxidant activity, and their major antioxidant compounds were identified and quantified by high-performance liquid chromatography (HPLC). Carnosic acid concentrations were correlated with (i) the free radical scavenging activity of these extracts, as measured by the 2,2-diphenyl-1-picrylhydrazyl assay (adjusted R(2) = 77.3%) and (ii) their inhibition of linoleic acid oxidation, as measured by the beta-carotene assay (adjusted R(2) = 44.1%). The correlation was broadly confirmed by the production of volatile aldehydes as measured by the hexanal assay. The variation of carnosic acid concentrations in extracts of 29 accessions, grown in field trials at three sites in England, was determined.     

Recovery mechanism of the antioxidant activity from carnosic acid quinone,an oxidized sage and rosemary antioxidant

A solution of carnosic acid quinone, which is a radical chain-termination product having no antioxidant activity in the antioxidant reaction of carnosic acid, recovers potent antioxidant activity upon standing. The HPLC analysis of an aged solution of carnosic acid quinone revealed that several antioxidants are produced in the solution. From the time-course and quantitative analyses of the formation of the products and their structural analysis, an antioxidant mechanism from carnosic acid quinone is proposed that includes a redox reaction of carnosic acid quinone in addition to the isomerization to lactone derivatives. In the first stage of antioxidation, carnosic acid, the reduction product from carnosic acid quinone, contributes to the potent antioxidant activity of the solution. This proposed mechanism can explain one of the reasons for the strong antioxidant activity of the extract of the popular herbs sage and rosemary.     

Rapid quantitative enrichment of carnosic acid from rosemary (Rosmarinus officinalis L.) by isoelectric focused adsorptive bubble chromatography

For the first time, the potent but unstable antioxidative diterpene carnosic acid could be enriched from an aqueous extract of rosemary (Rosmarinus officinalis L.) by isoelectric focused adsorptive bubble chromatography. Enrichment of carnosic acid in the foam was influenced by the pH value and the flow rate of the foam-forming gas. Efficiency was highest with diluted samples at pH 4. Under these conditions, the conversion of carnosic acid to carnosol was negligible. Transfer of carnosic acid to the foam from a standard solution in the presence of saponin as surfactive substance was similar to that from the aqueous rosemary extract.     

Antioxidant mechanism of carnosic acid: structural identification of two oxidation products.

To determine the antioxidant mechanism of food phenolics against the oxidation of food components, the reaction of carnosic acid, an antioxidative constituent of the popular herbs sage and rosemary, was investigated in the presence of ethyl linoleate and the radical oxidation initiator 2,2'-azobis(2,4-dimethylvaleronitrile). During this process, carnosic acid was oxidized to an o-quinone and a hydroxy p-quinone, the chemical structures of which were confirmed by physical and chemical techniques. From a quantitative time course analysis of the production of these quinones, an antioxidant mechanism of carnosic acid is proposed, consisting of the oxidative coupling reaction with the peroxyl radical at the 12- or 14-position of carnosic acid and subsequent degradation reactions.     

铝胁迫下水稻幼苗根尖表面pH和有机酸的动态变化

采用添加pH指示剂溴甲酚紫的琼脂糖凝胶平板技术, 检测了铝胁迫下水稻幼苗根尖表面pH和根尖细胞有机酸含量的动态变化。铝胁迫下, 幼苗根尖表面颜色在处理第1 h、3 h、6 h无明显变化; 而对照处理第1 h时水稻幼苗根尖表面颜色已发生明显变化, 呈浅橙色, 处理第3~6 h幼苗根尖表面变为橙红色。表明在正常条件(pH 4.4)下水稻幼苗根尖表面pH有碱化趋势, 铝胁迫条件下(pH 4.4)水稻幼苗根尖表面pH碱化的趋势被抑制。在测定的铝胁迫水稻幼苗根尖细胞细胞质10种有机酸中, 发现3种有机酸含量的变化趋势不同。草酸含量无明显变化; 柠檬酸含量在铝处理0~3 h内变化不明显, 处理3 h后迅速提高, 处理12 h达最大值后转而下降, 铝胁迫24 h时柠檬酸含量比胁迫12 h时降低16.27%, 差异达显著水平, 胁迫24 h后的柠檬酸含量变化不大但仍高于胁迫6 h的柠檬酸含量; 铝处理3 h后苹果酸含量较胁迫前下降幅度不大, 差异不显著(P>0.05), 3 h后显著下降, 6 h后下降趋势不明显。     

Characterization of two unknown compounds in methanol extracts of rosemary oil

In this study, two unknown compounds in rosemary oil, containing 3% carnosic acid and 0.3% carnosol, were identified and characterized. After methanol extraction, purification, and analysis by reversed-phase HPLC and LC-MS, a recovery of 92% (+/-8%) of carnosic acid was obtained, but no carnosol was found. However, two unknown compounds with a molecular weight of 330.2 and 302.2 were consistently detected. From additional LC-MS-MS, (1)H NMR, and elemental analyses, it became clear that the first compound (M(w) = 330.2) could not be carnosol. It was hypothesized that it originated from the breakdown of the intramolecular bond of carnosol, followed by the addition of a water molecule. Possibly, an unsaturated double bond was formed after dehydration. Assuming that this compound was an intermediate in the conversion to rosmanol, the second unknown compound (M(w) = 302.2) may have resulted from the breakdown of the intramolecular bond of rosmanol. Similarly, an unsaturated double bond may have been formed. After splitting off carbon oxide, a detectable molecule with a molecular weight of 302.2 was observed.     

Variation in diosgenin levels among 10 accessions of fenugreek seeds produced in western Canada

A collection of 10 accessions of fenugreek (Trigonella foenum-graecum L.), an annual legume, was grown during two summers at three plot locations in western Canada to assess whether genetic (accession) and environmental factors (site and year of production) influenced levels of diosgenin, a steroidal sapogenin. The 60 harvested seed samples, each analyzed by single determinations on three subsamples of defatted and dried seed material, were hydrolyzed by a microscale procedure in water containing 2-propanol (70%) and sulfuric acid (1 M). The extracts were analyzed by capillary gas chromatography with 6-methyldiosgenin as internal standard. Diosgenin levels from mature seeds ranged from 0.28 to 0.92% (28-92 microg/10 mg). Analysis of variance on combined diosgenin levels from the three sites and two years revealed that accession, accession x year, and site x year effects were significant for diosgenin content, whereas site, year, and site x accession effects were not. Four accessions, CN 19062, CN 19067, CN 19070, and CN 19071, were identified with high levels of diosgenin on the basis of the 2-year data set. In these accessions, mean levels of diosgenin plus yamogenin from seven site years were estimated at 0.70, 0.98, 0.84, and 0.87%, respectively.     

Exogenous application of humic acid and salicylic acid to alleviate seedling drought stress in two corn (Zea mays L.) hybrids

Efficacy of 1?mM humic (HA) and salicylic (SC) acids on SC 260 and SC 705 corn seedlings to alleviate drought stress via polyethylene glycol was studied via hydroponics at Shiraz University, Iran in a factorial, randomized design, with four replicates each. Under stress, SC 260 had higher electrolyte leakage compared to SC 705, and exogenous application of HA combined with SA decreased SC 705 electrolyte leakage. As a general trend, photosynthetic pigment content, relative water content, root and shoot length, mean number and diameter of central and peripheral root metaxylem, and K⁺ accumulation were higher in SC 705 treated with HA and SA compared to SC 260. Application of HA with SA could be an effective and low cost approach to ensure seedling establishment and plant growth in fields affected by soil drought in the early season, especially for the SC 705 corn hybrid in semi-arid regions.     

The role of potassium and zinc in reducing salinity and alkalinity stress conditions in two wheat genotypes

Soil salinity may reduce potassium (K) uptake due to strong competition with sodium cations at the root surface. In calcareous soils, zinc (Zn) precipitates in forms unavailable to plants. This study evaluated the responses of two wheat genotypes (C), Baccrosroshan and salinity-tolerant Line No. 4, to K and Zn fertilizers in both greenhouse and farm experiments with similar soil and water conditions. A factorial experiment with four K levels (K0 = 0, K1 = 72, K2 = 144 and K3 = 216 kg K₂O ha^?1) and three Zn levels (Zn0 = 0, Zn1 = 20 and Zn2 = 40 kg ha^?1) based on a randomized complete block design was employed. Analysis of variance results showed significant Zn × K × C interactions on all measured traits. Despite sufficient available potassium and illite clay in the root-growing medium, plants responded to K application. Yield components, grain yield and protein content of the two genotypes increased linearly as Zn × K increased. Considering Zn2K2 and Zn2K3, Line No. 4 produced 17% higher 1000-grain weight, 30% higher weight of grains per ear and 23% higher grain yield than Baccrosroshan in the farm experiment, and 10, 50, 16% higher values, respectively, in the greenhouse experiment. Results showed a significant relationship between grain weight per ear and grain yield. The achieved results highlight the importance of K and Zn nutrition under salt-stress conditions.     

Investigation of the changes in low molecular weight organic acids and other physiological parameters by nitric oxide application in two wheat cultivars exposed to boron stress

Boron (B) is one of the essential nutrients for the growth of plants, but its high concentrations are toxic for plants. Thus, B toxicity is a big challenge in crop cultivation. Nitric oxide (NO) is a small signaling molecule that has cytoprotective roles in plants. We investigated whether exogenous sodium nitroprusside (SNP), which is a NO donor, may succeed to alleviate B-induced toxicity in wheat cultivars. Seedlings were grown for 10 days in a growth chamber at 25°C with 16 hr light–8 hr dark photo cycle. After high B application, the effects of SNP on growth parameters; electrolyte leakage (EL); changes in reactive oxygen species [contents of hydrogen peroxide (H₂O₂), malondialdehyde (MDA), and proline]; the activities of antioxidant enzymes [glutathione peroxidase (GSHPx), glutathione reductase (GR), and glutathione S-transferase (GST)] and nitrate reductase (NR); and low molecular weight organic acid (LMWOAs) contents and also chlorophyll and total carotenoid contents were investigated in both shoots and roots of two different wheat cultivars. All experiments were carried out in triplicate. 0.2 mM SNP application ameliorated the chlorophyll and total carotenoid contents, and growth parameters such as shoot length, root length, and fresh weight in both wheat cultivars exposed to B stress. SNP reduced the B-induced lipid peroxidation, EL, and proline and H₂O₂ content in wheat cultivars. SNP application also increased the activities of NR and antioxidant enzymes, including GSHPx, GR, and GST in wheat cultivars exposed to B toxicity. All of the tested LMWOAs including succinic, propionic, butyric, oxalic, formic, malic, malonic, and benzoic acids were increased by SNP treatment in the shoots and roots of both wheat cultivars exposed to B toxicity. In conclusion, results obtained from this study have demonstrated that interactive effects of SNP with B considerably reduced the toxic effects of B in wheat cultivars.     

Low levels of genetic diversity detected by RAPD analysis in geographically distinct accessions of Bacopa monnieri

Brahmi (Bacopa monnieri) is atraditional Indian medicinal plant known for its natural nootropicaction of saponins present in large amount in its shoots. Acollection of 24 B.monnieri accessions from differentagro-climatic zones of India and an introduction from Malaysiamaintained in the field genebank at CIMAP was analysed for RAPDvariation. Among the 40 random primers tested, 29 primers generatedone or more polymorphic bands. The number of polymorphic bandsgenerated was primer dependent, ranging from 2 to maximum of 8.Similarity matrices were generated from the RAPD data on the basis ofNei's estimates of similarity indices and dendrograms wereconstructed based on UPGMA clustering. All the accessions were foundto be in the range of 0.8–1.0 of similarity, which isindicative of a narrow genetic base among the various accessions witha medium level of polymorphism. It was possible to differentiateindividual accessions, showing differences in morphological andgrowth properties at DNA level. The observed low levels of geneticvariation were attributed to interplay of sexual and vegetative modesof reproduction and similarity of local environments in habitats ofB. monnieri.     

两种基因型番茄对镉胁迫响应差异

【目的】使用两个番茄品种YSL189高镉积累和HZ903低Cd积累进行苗期水培实验,旨在揭示番茄品种间Cd耐性差异的机理,为分子育种改良番茄重金属耐性提供新的信息。【方法】本研究以前期鉴定的番茄高Cd积累品种YSL189和低Cd积累品种HZ903为材料,采用苗期人工气候箱水培的方式,分析了在Cd 50和100μmol/L胁迫下,供试品种间形态学指标、抗氧化酶活性、Cd积累量及相关基因表达的差异,同时分析了供试品种苗期对离子态Cd的吸收速率差异。【结果】1)在Cd 50和100μmol/L胁迫下,根长对Cd胁迫最敏感,株高和生物量次之;与低Cd积累品种HZ903相比,高Cd积累品种YSL189表现出生物量大、根系短、株高较高的特点。2)在50和100μmol/L Cd胁迫下,植株Cd积累量以根茎叶的趋势递减;同等胁迫下,YSL189植株根、茎、叶部的Cd积累量都显著高于HZ903。3)当培养介质中Cd浓度大于20μmol/L时,YSL189根系对离子态Cd的吸收速率显著高于HZ903;定量PCR结果显示,在50和100μmol/L Cd胁迫下,品种间Nramp2、Nramp3和ZIP的表达量差异趋势与Cd积累的差异趋势一致,即YSL189根系Cd吸收相关基因Nramp2,Nramp3和ZIP的表达量高于HZ903。4)在Cd 50和100μmol/L胁迫下,根、茎部的SOD(超氧化物歧化酶)、POD(过氧化物酶)和CAT(过氧化氢酶)活性都是YSL189高于HZ903,同时YSL189叶部POD和SOD活性也显著高于HZ903,同时,TBARS(巴比妥酸反应底物)含量所指示的根、茎部膜质过氧化伤害程度则没有品种间差异。【结论】YSL189根系对离子态Cd的高吸收速率以及Nramp2、Nramp3和ZIP基因的高表达量,可能是其获得高镉积累量的原因之一;同等胁迫条件下,YSL189植株体内高Cd浓度诱导了抗氧化酶的高活性,这说明YSL189植株对活性氧的清除能力强于HZ903。     

Potential of rosemary (Rosemarinus officinalis L.) diterpenes in preventing lipid hydroperoxide-mediated oxidative stress in Caco-2 cells

The effects of 24 h supplementation of Caco-2 cells with carnosic acid and carnosol, and their activities against 5 microM oleic acid hydroperoxide (OAHPx)-mediated oxidative stress, were investigated. At 24 h of incubation, under nonstressed and stressed conditions, both compounds at 25, 50, and 100 microM supplement concentrations reduced catalase activity, whereas changes in glutathione peroxidase and superoxide dismutase activities varied depending upon the concentrations. Relative to control cultures, carnosic acid and carnosol reduced membrane damage by 40-50% when stressed by OAHPx. Carnosic acid and carnosol inhibited lipid peroxidation by 88-100% and 38-89%, respectively, under oxidative stress conditions. Both compounds significantly lowered DNA damage induced by OAHPx. Results of this study suggest that antioxidant activities of carnosic acid and carnosol could be partly due to their ability to increase or maintain glutathione peroxidase and superoxide dismutase activities.     

植物低温胁迫响应的生化与分子生物学机制研究进展

综述了植物对低温胁迫响应的生化与分子生物学机制 ,即低温信号激活某些抗冻基因的表达 ,产生特异蛋白和渗透调节物质 ,使植物抗氧化胁迫能力和渗透调节能力提高 ,保护了植物细胞。而植物抗寒性的提高决定于抗冻基因的表达 ,如何通过分子生物学手段提高植物抗冻基因表达的效应是培育植物抗寒品系的关键。并展望了该领域今后研究的方向。     

Barley response to salt stress at varied levels of phosphorus

Increasing plant phosphorus (P) supply can increase or decrease salt tolerance of many plants. Barley (Hordeum vulgare L., cv. ACSAD 176) was grown in nutrient solution under controlled conditions to determine effects of P level on detrimental effects of sodium chloride (NaCl). Increasing level of P improved tolerance of barley to NaCl. At 3, 30, and 60 μM P, the NaCl concentrations to reduce shoot dry matter (DM) by 50% were 158, 193, and 260 mM, respectively. Increased NaCl levels reduced shoot P concentrations. Plants grown with NaCl had higher Internal P requirements. When NaCl in solution was 10, 150, and 300 mM, the corresponding concentrations of P in shoots required to obtain 50% DM were 1.6, 4.2, and 4.7 mg‐g^‐1 dry weight, respectively. Increasing solution P level from 3 to 60 μM P decreased sodium (Na) and increased potassium (K) concentrations in shoots. Accumulation of mineral ions for osmotic adjustment and restriction of Na accumulation in shoots was involved in P enhancement of salt tolerance of barley.     

Corn response to two fertilization rates under Sw Spain conditions

Abstract

Corn cv. PRISMA response (growth, plant composition, and yield) was studied in relation to two fertilizer treatments: the high rate used in irrigated fields in SW Spain (1000 kg/ha 15–15–15 fertilizer plus two applications of 400 kg urea (46%N)/ha); and the same reduced to one‐third. Plant height (～ 290 cm), specific leaf area (0.018 m²/g), ear weight (～210 g), kernel weight per ear (～185 g), and estimated yield (～16 Mg/ha) were similar with both treatments. Plant nutrient contents were similar in the leaf level, with both treatments, although the N content of stalk and kernel (at harvest) were higher (P<0.05) when the high fertilization dose was applied. DRIS indices presented N and S as the more balanced nutrients, and in general the P and Mg contents were comparatively low, and Ca and K comparatively high. Amounts of N and P removed by corn (above‐ground part) were higher than those fertilized at the lower rate. Removed K was considerably higher than the loaded amount, whichever rate of fertilization was considered. When fertilized with a comparatively low rate (for irrigated regimes in SW Spain), the natural reserves of the previously fertilized sandy loam soil used in the assay contributed to achieve a high yield with a high‐yielding corn crop.     

Role of water stress in differential aluminum tolerance of two barley cultivars grown in an acid soil

Two cultivars of barley (Hordeum vulgare L.), Al‐sensitive ‘Dayton’ and Al‐tolerant ‘Kearney’, were grown under controlled environmental conditions to determine the influence of Al stress and water stress imposed separately and in combination with one another. Plants were grown for 4 weeks in polyethylene‐lined, waxed cartons containing 1 kg of acid, Al‐toxic, Tatum subsoil (clayey, mixed, thermic, Typic Hapludult) at high (pH 4.7) or low (pH 6.6) Al stress. During the final 2 weeks they were also subjected to low (‐20 to ‐40 kPa) or high (‐60 to ‐80 kPa) water stress. Under low water stress, little difference in the growth or appearance of the two cultivars was found, even in the presence of low Al stress (pH 6.6). When high water stress treatment was superimposed on low Al stress treatment, however, significant differences between the two cultivars in biomass production, leaf enlargement, and tillering resulted. When high water stress was combined with high Al stress (pH 4.7), these differences in vegetative growth were further magnified. Thus, drought exacerbates the stress effects of Al toxicity in plants and may account for a significant portion of the reduction in yield commonly observed in acid soils under field conditions and formerly attributed to Al toxicity alone. By increasing soil moisture level, the growth suppressive effect of Al toxicity was significantly reduced.     

Comparison of oil and phytosterol levels in germplasm accessions of corn, teosinte, and Job's tears

Seeds of 49 accessions of corn (Zea mays ssp. mays), 9 accessions of teosinte (Zea species that are thought to be ancestors and probable progenitors to corn), and 3 accessions of Job's tears (Coix lacryma), obtained from a germplasm repository, were ground and extracted with hexane. Whole kernel oil yields and levels of four phytonutrients (free phytosterols, fatty acyl phytosterol esters, ferulate phytosterol esters, and gamma-tocopherol) in the oils were measured. Among the seeds tested, oil yields ranged from 2.19 to 4.83 wt %, the levels of ferulate phytosterol esters in the oil ranged from 0.047 to 0.839 wt %, the levels of free phytosterols in the oil ranged from 0.54 to 1.28 wt %, the levels of phytosterol fatty acyl esters in the oil ranged from 0.76 to 3.09 wt %, the levels of total phytosterols in the oil ranged from 1.40 to 4.38 wt %, and the levels of gamma-tocopherol in the oil ranged from 0.023 to 0.127 wt %. In general, higher levels of all three phytosterol classes were observed in seed oils from accessions of Zea mays ssp. mays than in seed oils from accessions of the other taxonomic groups. The highest levels of gamma-tocopherol were observed in teosinte accessions.     

Enhanced sensitivity of a glutathione-deficient yeast strain to thiram and dimethyldithiocarbamic acid

The sensitivity of a glutathione-deficient mutant of yeast towards thiram and dimethyl dithiocarbamic acid was compared to that of a wild strain. It was shown that the GSH contents of the cell correlated with the toxicity of both drugs, and that glutathione is probably involved in the metabolism of these drugs.