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1.
Mannan Hajimahmoodi Mohammad Ali Faramarzi Najmeh Mohammadi Neda Soltani Mohammad Reza Oveisi Nastaran Nafissi-Varcheh 《Journal of applied phycology》2010,22(1):43-50
Antioxidant activities of both cells and extracellular substances were evaluated in 12 soil-isolated strains of microalgae
according to FRAP and DPPH-HPLC assays. Their total phenolic contents were also determined by Folin–Ciocalteu method. Extractions
were performed with hexane, ethyl acetate, and water. The results of FRAP assay showed that algal cells contained considerable
amounts of antioxidants from 0.56 ± 0.06 to 31.06 ± 4.00 μmol Trolox g−1 for Microchaete tenera hexane extract and Chlorella vulgaris water extract, respectively. In water fractions of extracellular substances, the antioxidants were from 1.30 ± 0.15 μmol
Trolox g−1 for Fischerella musicola to 73.20 ± 0.16 μmol Trolox g−1 for Fischerella ambigua. Also, DPPH-HPLC assay represented high antioxidant potential of water fractions. The measured radical-scavenging activities
of the studied microalgae were at least 0.15 ± 0.02 in Nostoc ellipsosporum cell mass to a maximum of 109.02 ± 8.25 in C. vulgaris extracellular substance. The amount of total phenolic contents varied in different strains of microalgae and ranged from
zero in hexane extract to 19.15 ± 0.04 mg GAE g−1 in C. vulgaris extracellular water fraction. Significant correlation coefficients between two measured parameters indicated that phenolic
compounds were a major contributor to the microalgal antioxidant capacities. 相似文献
2.
《Journal of bryology》2013,35(1):151-158
AbstractThe concentration of chlorophyll a, b, and total chlorophyll have been monitored on a seasonal basis in Brachythecium rutabulum. Total chlorophyll increases during summer full canopy conditions from 1.70 mg chl g?1 on 8 May to 11.1 mg chl g?1 on 11 October. Photosynthetic-illumination curves show that during this period light saturation declines from 200 μmol m?2s?1 to 30 μmol m?2s?1 by 6 July, and light compensation falls dramatically from 65 μmol m?2s?1 to 4 μmol m?2s?1. The data also appear to support the conclusion that there is concurrently an increase in the density of photosynthetic units by the end of September. 相似文献
3.
The extent to which the parasitic angiosperm Striga hermonthica reduces the growth of its sorghum host is dependent on the concentration of nitrogen (as NH4NO3 in 40% Long Ashton Solution) supplied to the plants. The biomass of 0.5,1 and 2 mol m?3 N-grown infected plants was 22,30 and 66%, respectively, of uninfected plants after 140d growth. The biomass of 3 and 4 mol m?3 N-grown infected plants differed little from uninfected plants. No grain was set in 0.5 and 1 mol m?3 N-grown infected plants, grain yield reached 42 and 73% of controls in 2 and 3 mol m?3 N-grown plants, and was unaffected in 4 mol m?3 N-grown plants. Striga hermonthica also altered the allometry and architecture of the host, at all but the highest N concentration. Higher N concentration (3 and 4 mol m ?3 N) reduced the growth of S. hermonthica. Foliar N concentrations in sorghum ranged from 11 mg g?1 dwt. in 0.5 mol m?3 N-grown plants, to 28 mg g?1 dwt. in 4 mol m?3 N-grown plants, and were not affected by S. hermonthica. Higher N concentrations were measured in S. hermonthica, and ranged from 18 to 45 mg g?1 dwt. in 0.5 and 3 mol m?3 N-grown plants, respectively. The relationship between photosynthesis (CO2 flux) and N concentration differed between uninfected and infected sorghum. This was most apparent in 0.5 mol m?3 N-grown plants, with rates of 16 and 11 μmol m?2 s?1 in uninfected and infected plants, respectively (at 1500–1800 μmol m?2 s?1 photosynthetic photon flux density). At higher N concentrations, this difference was smaller, with both sets of plants reaching 26 μmol m?2 s?1 at 4 mol m?3 N. Varying the level of S. hermonthica infection showed that the effect of N on host photosynthesis cannot be explained by differences in the mass or number of parasites supported by the host. At low levels of infection in 1 mol m?3 N-grown plants, the negative effect of the parasite was reversed, and photosynthesis in infected plants exceeded that in uninfected plants by 20%. Photosynthesis in S. hermonthica at 3 mol m?3 N (8 μmol m?2 s?1) was double that in 0.5 mol m?3 N-grown plants. Stable carbon isotope and gas exchange measurements data demonstrated that this higher level of autotrophic carbon fixation was accompanied by a lower dependency on hetero trophic carbon. The latter ranged from 27 to 6% in 0 5 mol m?3 and 3 mol m?3 N-grown plants, respectively. 相似文献
4.
SHEILA F. CHRISTOPHER BLAIR D. PAGE JOHN L. CAMPBELL MYRON J. MITCHELL 《Global Change Biology》2006,12(2):364-381
Two nearly adjacent subcatchments, located in the Adirondack Mountains of New York State, US, with similar atmospheric inputs of N (0.6 kmol ha?1 yr?1), but markedly different stream water solute concentrations, provided a unique opportunity to evaluate the mechanisms causing this variation. Subcatchment 14 (S14) had much greater stream water Ca2+ and NO3? concentrations (851 and 73 μmolc L?1, respectively) than Subcatchment 15 (S15) (427 and 26 μmolc L?1, respectively). To elucidate factors affecting the variability in stream water concentrations, soil and forest floor samples from each subcatchment were analyzed for total elemental cations and extractable N species. Mineral soil samples were also analyzed for exchangeable cations. Tree species composition was characterized in each subcatchment and potential differences in land use history and hydrology were also assessed. Compared with S15, soils in S14 had significantly higher total elemental Ca2+ in the forest floor (380 vs. 84 μmol g?1), Bs horizon (e.g. 1361 vs. 576 μmol g?1) and C horizon (1340 vs. 717 μmol g?1). Exchangeable Ca2+ was also significantly higher in the mineral soil (64 μmol g?1 in S14 vs. 8 μmol g?1 in S15). Extractable NO3? was higher in S14 compared with S15 in both the forest floor (0.1 vs. 0.01 μmol g?1) and Bs horizon (0.2 vs. 0.07 μmol g?1) while extractable NH4+ was higher in S14 vs. S15 in the forest floor (7 vs. 5 μmol g?1). The total basal area of ‘base‐rich indicator’ tree species (e.g. sugar maple, American basswood, eastern hophornbeam) was significantly greater in S14 compared with S15, which had species characteristic of sites with lower base concentrations (e.g. American beech and eastern white pine). The disparity in stream water Ca2+ and NO3?, concentrations and fluxes between S14 and S15 were explained by differences in tree species composition and soil properties rather than differences in land use or hydrology. The marked difference in soil Ca2+ concentrations in S14 vs. S15 corresponded to the higher stream water Ca2+ and the larger contribution of base‐rich tree species to the overstory biomass in S14. Soil under such species is associated with higher net mineralization and nitrification and likely contributed to the higher NO3? concentrations in the drainage waters of S14 vs. S15. Studies investigating differences in spatial and temporal patterns of the effects of chronic N deposition on surface water chemistry need to account for changes in tree species composition and how vegetation composition is influenced by soil properties, as well as climatic and biotic changes. 相似文献
5.
Cledes TerezinhadeOliveira Beatriz Helena LameirodeNoronhaSalesMaia Aurea PortesFerriani Vidiany AparecidaQueirozSantos Mrio AntnioAlvesdaCunha Sirlei DiasTeixeira 《化学与生物多样性》2019,16(2)
This is the first time that composition, antimicrobial potential and antioxidant ability of essential oil from the leaves of Baccharis oreophila are reported. Essential oil was obtained by hydrodistillation and analyzed by GC/MS. Antimicrobial potential was evaluated by diffusion disk and broth microdilution methods. ABTS.+, DPPH. and FRAP methods were employed for antioxidant activity evaluation. Essential oil yield was 0.47 %. Sixty‐five compounds were identified, representing 88.53 % of the total essential oil, which showed to be rich in oxygenated (37.88 %) and hydrocarbons sesquiterpenes (34.84 %). The main constituents were khusimone (16.37 %) and spathulenol (16.12 %). Antimicrobial activity was verified against S. aureus (10.33±0.5 mm, MIC: 1250 μg mL?1) and C. albicans (8.66±0.5 mm, MIC: >2500 μg mL.1). Antioxidant ability was evidenced by FRAP (4.09 μmol FeSO4 E mL?1), ABTS.+ (1.45 μmol TE mL?1) and DPPH. (1.04 μmol TE mL?1) scavenging capacity. Results showed that this essential oil has interesting biological potential, encouraging further investigations especially in relation to action mechanisms of antimicrobial and antioxidant activity. 相似文献
6.
Felisa Rey Paulo Cartaxana Sónia Cruz Tânia Melo M. Rosário Domingues 《Journal of phycology》2023,59(5):1025-1040
Marine algae are one of the most important sources of high-value compounds such as polar lipids, omega-3 fatty acids, photosynthetic pigments, or secondary metabolites with interesting features for different niche markets. Acetabularia acetabulum is a macroscopic green single-celled alga, with a single nucleus hosted in the rhizoid. This alga is one of the most studied dasycladalean species and represents an important model system in cell biology studies. However, its lipidome and pigment profile have been overlooked. Total lipid extracts were analyzed using hydrophilic interaction liquid chromatography-high resolution mass spectrometry (HILIC-HRMS), tandem mass spectrometry (MS/MS), and high-performance liquid chromatography (HPLC). The antioxidant capacity of lipid extracts was tested using DPPH and ABTS assays. Lipidomics identified 16 polar lipid classes, corresponding to glycolipids, betaine lipids, phospholipids, and sphingolipids, with a total of 191 lipid species, some of them recognized by their bioactivities. The most abundant polar lipids were glycolipids. Lipid classes less studied in algae were identified, such as diacylglyceryl-carboxyhydroxymethylcholine (DGCC) or hexosylceramide (HexCer). The pigment profile of A. acetabulum comprised carotenoids (17.19%), namely cis-neoxanthin, violaxanthin, lutein and β,β-carotene, and chlorophylls a and b (82.81%). A. acetabulum lipid extracts showed high antioxidant activity promoting a 50% inhibition (IC50) with concentrations of 57.91 ± 1.20 μg · mL−1 (438.18 ± 8.95 μmol Trolox · g−1 lipid) in DPPH and 20.55 ± 0.60 μg · mL−1 in ABTS assays (918.56 ± 27.55 μmol Trolox · g−1 lipid). This study demonstrates the potential of A. acetabulum as a source of natural bioactive molecules and antioxidant compounds. 相似文献
7.
Growth, photosynthesis, dark respiration and pigment contents were monitored in adult sporophytes of the Antarctic brown alga Desmarestia menziesii J. Agardh grown under fluctuating Antarctic daylength conditions. Growth rates were closely coupled to daylength variations with values varying from 0.05% d?1 in winter condition (July-August) to 0.5% d?1 in early summer (December). Photosynthetic pigments had maximum values of 1.8 mg g?1 FW (chlorophyll a), 0.4 mg g?1 FW (chlorophyll c) and 0.9 mg g?1 FW (fucoxanthin) in summer. These changes were also closely related to individual size and biomass of the plants. Net photosynthesis (Pmax), on a fresh weight basis, showed a clear seasonal pattern with highest rates of 25μmol O2 g?1 FW h?1 in October and minima close to 9μmol O2 g?1 FW h?1 in April. Dark respiration was high in spring (13μmol O2 g?1 FW h?1) approximately coinciding with growth peaks. Likewise, photosynthetic efficiency (α) and the initial saturating light point of photosynthesis (lk) increased significantly in spring [1.3 μimol O2 g?1 FW h?1 (μmol m?2 s?1)?1 and 26μmol photons m?2 s?1, respectively]. In the case of α, no significant differences between fresh weight and Chl a based rates were found. The results of the present study are the first that demonstrate seasonality of physiological parameters in D. menziesii sporophytes and confirm also that phenology and physiology of macroalgae can be simulated in the laboratory. On the other hand this study adds new elements to the explanation of the life strategy of D. menziesii, in particular that algal growth and photosynthesis occur under a programmed seasonal pattern. 相似文献
8.
Antonella Smeriglio Valeria D'Angelo Marcella Denaro Domenico Trombetta Francesco Maria Raimondo Maria Paola German 《化学与生物多样性》2019,16(9)
In this study, we investigated the phenolic composition of the crude extract (MeOH 80 %) of Alnus cordata (Loisel .) Duby stem bark (ACE) and its antioxidant and skin whitening properties. RP‐LC‐DAD analysis showed a high content of hydroxycinnamic acids (47.64 %), flavanones (26.74 %) and diarylheptanoids (17.69 %). Furthermore, ACE exhibited a dose‐dependent antioxidant and free‐radical scavenging activity, expressed as half‐maximal inhibitory concentration (IC50): Oxygen radical absorbance capacity (ORAC, IC50 1.78 μg mL?1)>Trolox equivalent antioxidant capacity (TEAC, IC50 3.47 μg mL?1)>2,2‐Diphenyl‐1‐picrylhydrazyl (DPPH, IC50 5.83 μg mL?1)>β‐carotene bleaching (IC50 11.58 μg mL?1)>Ferric reducing antioxidant power (FRAP, IC50 17.28 μg mL?1). Moreover, ACE was able to inhibit in vitro tyrosinase activity (IC50 77.44 μg mL?1), l ‐DOPA auto‐oxidation (IC50 39.58 μg mL?1) and in an in vivo model it exhibited bleaching effects on the pigmentation of zebrafish embryos (72 h post fertilization) without affecting their development and survival. In conclusion, results show that A. cordata stem bark may be considered a potential source of agents for the treatment of skin disorders due to its bleaching properties and favorable safety profiles, associated to a good antioxidant power. 相似文献
9.
Lisheng Xu Shoubiao Zhou Longhua Wu Na Li Liqiang Cui Yongming Luo 《International journal of phytoremediation》2009,11(3):283-295
Field survey, hydroponic culture, and pot experiments were carried out to examine and characterize cadmium (Cd) and zinc (Zn) uptake and accumulation by Sedum jinianum, a plant species native to China. Shoot Cd and Zn concentrations in S. jinianum growing on a lead/Zn mine area reached 103–478 and 4165–8349 mg kg?1 (DM), respectively. The shoot Cd concentration increased with the increasing Cd supply, peaking at 5083 mg kg?1 (DM) when grown in nutrient at a concentration of 100 μmol L?1 for 32 d, and decreased as the solution concentration increased from 200 to 400 μmol L?1. The shoot-to-root ratio of plant Cd concentrations was > 1 when grown in solution Cd concentrations ≤ 200 μmol L?1. Foliar, stem, and root Zn concentrations increased linearly with the increasing Zn level from 1 to 9600 μmol L?1. The Zn concentrations in various plant parts decreased in the order roots > stem > leaves, with maximum concentrations of 19.3, 33.8, and 46.1 g kg?1 (DM), respectively, when plants were grown at 9600 μmol Zn L?1 for 32 d. Shoot Cd concentrations reached 16.4 and 79.8 mg kg?1 (DM) when plants were grown in the pots of soil with Cd levels of 2.4 mg kg?1 and 9.2 mg kg?1, respectively. At soil Zn levels of 619 and 4082 mg kg?1, shoot Zn concentrations reached 1560 and 15,558 mg kg?1 (DM), respectively. The results indicate that S. jinianum is a Cd hyperaccumulator with a high capacity to accumulate Zn in the shoots. 相似文献
10.
Anne Herbst Viraj Ranawakage Takashi Asaeda Hendrik Schubert 《Phycological Research》2022,70(1):57-65
The immediate effect of zinc (Zn) and hydrogen peroxide (H2O2) in Chara braunii was analyzed in short-time exposure experiments. The exposure concentrations were 12.3, 18.4, and 24.5 μmol L?1 H2O2, 12, 60, and 120 mg L?1 Zn, and 12.3 μmol L?1 H2O2 + 12 mg L?1 Zn, 12.3 μmol L?1 H2O2 + 60 mg L?1 Zn, and 18.4 μmol L?1 H2O2 + 12 mg L?1 Zn. The stress response of C. braunii was analyzed by measuring photosynthetic photosystem II activity, chlorophyll a and b and carotenoid contents, the H2O2 concentration, and antioxidant enzyme activities of ascorbic peroxidase, catalase, and guaiacol peroxidase. The short-term addition of Zn reduced pigment contents in C. braunii. Chlorophyll a and b and carotenoid contents in H2O2-exposed C. braunii were as high as in control plants. Photosynthesis was reduced in H2O2-treated C. braunii and the short-term addition of Zn did not affect the electron transport rate. H2O2 concentration and antioxidant enzyme activities in C. braunii were not significantly different between control and exposed plants. Trends of enzymatic adaptation were described: the H2O2-induced stress response was characterized by increased antioxidant enzyme activities, whereas Zn inactivated catalase in C. braunii. 相似文献
11.
Secondary metabolites 2,4‐dihydroxy‐l,4‐benzoxazin‐3‐one(DIBOA) and 2‐benzoxazolinone (BOA) were quantified in different morphological parts of A. mollis. The highest DIBOA content was determined in the stamens of the flowers (57.0 umol g?1 fr. wt). Content of DIBOA in leaves decreased from approximately 28 μmol g?1 fr. wt for younger leaves (less than 4 wk old), to 3.0 μmol g?1 fr. wt. for the older ones (more than 13 wk of age). The concentration of BOA was lower than that of DIBOA in all parts of the plant (less than 1.5 μmol g?1 fr. wt) and showed a small variation. Younger leaves exhibit antifeeding activity against the larvae of Pseudaletia impuncta a native moth that feeds on cereals. These results suggest that DIBOA protects A. mollis species from phytophagous insects. 相似文献
12.
Mirjana D. Marčetić Silvana D. Petrović Marina T. Milenković Marjan S. Niketić 《Central European Journal of Biology》2014,9(2):149-155
The chemical composition, antimicrobial and antioxidant activity of Eryngium palmatum, an endemic plant species from the Balkan Peninsula, were investigated. The flavonoids apigenin (9.5±0.3 mg g?1) and apigenin 7-O-glucoside (2.4±0.1 mg g?1) were determined in a methanol extract of aerial parts using HPLC analysis. The methanol extract of roots contained catechin (5.0±0.1 mg g?1), epicatechin (2.9±0.1 mg g?1), chlorogenic acid (1.6±0.0 mg g?1), gallic acid (0.9±0.0 mg g?1) and rosmarinic acid (0.9±0.2 mg g?1). GC-FID and GCMS analysis of a chloroform extract of aerial parts showed that the main volatile constituents were falcarinol, linoleic acid, hexadecanoic acid and methyl linoleate (comprising 32.6%; 24.4%; 19.9; 13.2% of the volatile fraction, respectively), while octanoic acid, tetradecanol and dodecanol dominated in the chloroform extract of the roots (34.9%; 25.8%; 22.2% of the volatile fraction, respectively). Investigation of antimicrobial activity by broth microdilution showed that the methanol and chloroform extracts of aerial parts and roots exerted a significant effect (MIC 3.5–15.6 μg mL?1) against tested Gram-positive and Gram-negative bacteria. The methanol extracts of aerial parts or roots exerted moderate ferric reducing antioxidant power, DPPH radical scavenging activity and hydroxyl radical scavenging activity. 相似文献
13.
《Saudi Journal of Biological Sciences》2020,27(4):1009-1015
The grape is a matrix rich in bioactive compounds and its production generates large quantities of by-products, such as grape stems, which, to date, present low commercial value. However, there is a growing interest in the application of this material as a source of phenolic compounds. Therefore, the present study aims at assessing the phytochemical profile of (poly)phenolic extracts of white Portuguese grape stem varieties produced in the Região Demarcada do Douro (Portugal). The antioxidant activity determined by several assays, as well as the antimicrobial activity using the disc diffusion method against human gastrointestinal pathogenic bacteria of the hydromethanolic extracts, were evaluated. This work presents very positive results as the rich composition in phenolic compounds (94.71–123.09 mg GA−1 and 0.02–73.79 mg g−1 for the total phenol content and for individual phenolics, respectively) presented by grape stems can explain the high antioxidant (0.37–1.17 mmol Trolox g−1) and antimicrobial activities against, essentially, Gram-positive bacteria, and in some cases with higher efficacy than commercial antibiotics. Thus, demonstrating that this wine by-product should deserve greater attention from the pharmaceutical industries due to its excellent biological properties and characteristics not yet applied. 相似文献
14.
The effect of photosynthetically active radiation and temperature on the photosynthesis of two Vietnamese species of Sargassum,S. mcclurei and S. oligocystum,based on the field and laboratory measurements
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Ryuta Terada Triet D. Vo Gregory N. Nishihara Kazuya Matsumoto Shogo Kokubu Yuki Watanabe Shigeo Kawaguchi 《Phycological Research》2016,64(4):230-240
SUMMARY The effects of photosynthetically active radiation (PAR) and temperature on the photosynthesis of two Vietnamese brown algae, Sargassum mcclurei and S. oligocystum (Fucales), were determined by field and laboratory measurements. Dissolved oxygen sensors and pulse‐amplitude modulated (PAM) fluorometry were used for the measurements of photosynthetic efficiency. A Diving‐PAM revealed that underwater measurements of the effective quantum yield (Φ PSII ) of both species declined with increasing incident PAR, with minimum Φ PSII occurring during noon to early afternoon. Φ PSII recovered in the evening, indicating photo‐adaptation to excessive PAR. In laboratory experiments, Φ PSII also decreased under continuous exposure to 1000 μmol photons m?2 s?1; and full recovery occurred after 12 h of dark acclimatization. The net photosynthesis – PAR experiments of S. mcclurei and S. oligocystum conducted at 28°C revealed that the net photosynthetic rate quickly increased at PAR below the saturation irradiance of 361 and 301 μmol photons m?2 s?1 and nearly saturated to maximum net photosynthetic rates of 385 and 292 μg O2 gww ? 1 min?1 without photoinhibition, respectively. Gross photosynthesis and dark respiration experiments determined over a range of temperatures (12–40°C), revealed that the maximum gross photosynthetic rates of 201 and 147 μg O2 gww ? 1 min?1 occurred at 32.9 and 30.7°C for S. mcclurei and S. oligocystum, respectively. The dark respiration rates increased exponentially over the temperature ranges examined. The estimated maximum value of the maximum quantum yield occurred at 19.3 and 20.0°C and was 0.76 and 0.74, respectively. Similar to the natural habitat of the study site, these two species tolerated the relatively high temperatures and broad range of PAR. The ability of these species to recover from exposure to high PAR is one of the mechanisms that allow them to flourish in the shallow water environment. 相似文献
15.
C. Wiencke J. Rahmel U. Karsten G. Weykam G. O. Kirst 《Plant biology (Stuttgart, Germany)》1993,106(1):78-87
The photosynthetic performance of macroalgae isolated in Antarctica was studied in the laboratory. Species investigated were the brown algae Himantothallus grandifolius, Desmarestia anceps, Ascoseira mirabilis, the red algae Palmaria decipiens, Iridaea cordata, Gigartina skottsbergii, and the green algae Enteromorpha bulbosa, Acrosiphonia arcta, Ulothrix subflaccida and U. implexa. Unialgal cultures of the brown and red algae were maintained at 0°C, the green algae were cultivated at 10°C. IK values were between 18 and 53 μmol m?2 s?1 characteristic or low light adapted algae. Only the two Ulothrix species showed higher IK values between 70 and 74 μmol m?2 s?1. Photosynthesis compensated dark respiration at very low photon fluence rates between 1.6 and 10.6 μmol m?2 s?1. Values of α were high: between 0.4 and 1.1 μmol O2 g?1 FW h?1 (μmol m?2 s?1)?1 in the brown and red algae and between 2.1 and 4.9 μmol O2 g?1 FW h?1 (μmol m?2 s?1)?1 in the green algal species. At 0°C Pmax values of the brown and red algae ranged from 6.8 to 19.1 μmol O2 g?1 FW h?1 and were similarly high or higher than those of comparable Arctic-cold temperate species. Optimum temperatures for photosynthesis were 5 to 10°C in A. mirabilis, 10°C in H. grandifolius, 15°C in G. skottsbergii and 20°C or higher in D. anceps and I. cordata. P: R ratios strongly decreased in most brown and red algae with increasing temperatures due to different Q10 values for photosynthesis (1.4 to 2.5) and dark respiration (2.5 to 4.1). These features indicate considerable physiological adaptation to the prevailing low light conditions and temperatures of Antarctic waters. In this respect the lower depth distribution limits and the northern distribution boundaries of these species partly depend on the physiological properties described here. 相似文献
16.
New norcantharidin analogs were designed and obtained as compounds with biological activity. As a starting material, exo‐7‐oxabicyclo[2.2.1]heptane‐2,3‐dicarboxylic acid anhydride was used. Three groups of compounds: dicarboximides, triazoles and thiazolidines were obtained in multistep reactions. The 1H‐ and 13C‐NMR spectra were used to confirm the structures of all obtained products and they were in agreement with the proposed structure of substances. All derivatives were screened for their antioxidant activity. The most promising group was dicarboximides ( 1 – 4 , 6 ). Derivatives 2–4 displayed antioxidant activity with EC50=7.75–10.89 μg/ml, which may be comparable to strong antioxidant Trolox (EC50=6.13 μg/ml). Excellent activity with EC50=10.75 μg/ml also presented norcantharidin analog with 1,2,4‐triazole system ( 12 ). 相似文献
17.
Bairon Jorquera Ailin Mayorga Dr. Helena Quintero-Pertuz Jessica Mejía Gabriel Núñez Paula Núñez Pizarro Dr. María Fernanda Arias-Santé Dr. Gloria Montenegro Dr. Adriano Costa de Camargo Dr. Raquel Bridi 《化学与生物多样性》2023,20(10):e202301015
Bee bread (BB) is a beehive product generated upon fermentation of pollen combined with flower nectar and glandular secretions. The potential application of BB is related to its nutritional and functional components, including phenolic compounds. This is the first prospective study on palynological parameters, phenolics, antioxidant, and antibacterial activity of Chilean bee bread in vitro. The tested material exhibited high levels of phenolics (1340±186 mg GAE/100 g BB) and showed antioxidant capacity as determined by the FRAP (51±2 μmol Trolox equivalent/g BB) and ORAC-FL (643±64 μmol Trolox equivalent/g BB) and antibacterial activity against Streptococcus pyogenes. Furthermore, the phenolic acids and flavonoids was determined using liquid chromatography-mass spectrometry, and the concentration was determined using liquid chromatography with diode array detection. Kaempferol, quercetin, ferulic acid, and rutin were the main phenolics found. This study demonstrates the bioactive potential of Chilean BB and supports the evidence that this bee product is a promising source of antioxidants and antimicrobial compounds. 相似文献
18.
Free-air CO2 enrichment of wheat: leaf flavonoid concentration throughout the growth cycle 总被引:1,自引:0,他引:1
Marc Estiarte Josep Peñuelas Bruce A. Kimball Donald L. Hendrix Paul J. Pinter Jr Gerard W. Wall Robert L. LaMorte Douglas J. Hunsaker 《Physiologia plantarum》1999,105(3):423-433
To test the predictions that plants will have a larger flavonoid concentration in a future world with a CO2-enriched atmosphere, wheat (Triticum aestivum L. cv. Yecora Rojo) was grown in a field experiment using FACE (free-air CO2 enrichment) technology under two levels of atmospheric CO2 concentration: ambient (370 μmol mol?1) and enriched (550 μmol mol?1), and under two levels of irrigation: well-watered (100% replacement of potential evapotranspiration) and half-watered. We also studied the effects of CO2 on the concentration of total non-structural carbohydrates (TNC) and nitrogen (N), two parameters hypothesized to be linked to flavonoid metabolism. Throughout the growth cycle the concentration of isoorientin, the most abundant flavonoid, decreased by 62% (from an average of 12.5 mg g?1 on day of year (DOY) 41 to an average of 4.8 mg g?1 on DOY 123), whereas the concentration of tricin, another characteristic flavone, increased by two orders of magnitude (from an average of 0.007 mg g?1 of isoorientin equivalents on DOY 41 to an average of 0.6 mg g?1 of isoorientin equivalents on DOY 123). Although flavonoid concentration was dependent on growth stage, the effects of treatments on phenology did not invalidate the comparisons between treatments. CO2-enriched plants had higher flavonoid concentrations (14% more isoorientin, an average of 7.0 mg g?1 for ambient CO2 vs an average of 8.0 mg g?1 for enriched CO2), higher TNC concentrations and lower N concentrations in ukpper canopy leaves throughout the growth cycle. Well-irrigated plants had higher flavonoid concentrations (11% more isoorientin, an average of 7.1 mg g?1 for half watered vs an average of 7.9 mg g?1 for well-watered) throughout the growth cycle, whereas the effect of irrigation treatments on TNC and N was more variable. These results are in accordance with the hypotheses that higher carbon availability promoted by CO2-enrichment provides carbon that can be invested in carbon-based secondary compounds such as flavonoids. The rise in atmospheric CO2 may thus indirectly affect wheat-pest relations, alter the pathogen predisposition and improve the UV-B protection by changing flavonoid concentrations. 相似文献
19.
Xiumin Guan Xiaoxia Liu Zengquan Lu Zhangwu Zhao Qingwen Zhang & Jingyuan Xia 《Entomologia Experimentalis et Applicata》2009,132(1):50-58
Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) causes huge economic losses in cotton production around the world. Tannin, one of the important secondary substances in cotton plants, can increase the δ‐endotoxin activity of Bacillus thuringiensis ssp. kurstaki. The mechanism of interaction between tannin and Bt toxin on H. armigera is unclear. We investigated the interaction between tannic acid and Cry1Ac toxin in H. armigera, and monitored survival, growth, and development during the larval period after treating the larvae with four concentrations of Cry1Ac toxin (0, 2, 8, and 14 μg?1) alone or in combination with four concentrations of tannic acid (0, 0.5, 1, and 2 mg g?1). Mortality of larvae treated with both tannic acid and Cry1Ac was higher than the mortality of larvae treated with tannic acid or Cry1Ac alone. Mortality was 47.5 and 51.5% in larvae treated with 14 μg g?1 Cry1Ac alone or 2 mg g?1 tannic acid alone, respectively. In contrast, larval mortality was 75% when treated with the mixture of 14 μg g?1 Cry1Ac and 2 mg g?1 tannic acid, suggesting that a mixture of the two enhanced the effectiveness of each one alone. The developmental time of larvae treated with the combination of tannic acid and Cry1Ac was significantly longer than when they were treated with Cry1Ac or tannic acid alone. Larval weight, pupal weight, and pupation rate were also significantly reduced in larvae treated with both toxins, compared with the larvae treated with either toxin alone. These results showed that the interactive effect of tannic acid and Cry1Ac on larval growth inhibition is additive, and that tannic acid improves Cry1Ac toxicity to insects. Tannic acid used in combination with B. thuringiensis might potentially reduce overall insecticide use, thus delaying development of insecticide resistance. 相似文献
20.
Variations of pigment content in the microscopic conchocelis stage of four Alaskan Porphyra species were investigated in response to environmental variables. Conchocelis filaments were cultured under varying conditions of irradiance and nutrient concentrations for up to 60 d at 11°C and 30 psu salinity. Results indicate that conchocelis filaments contain relatively high concentrations of phycobilins under optimal culture conditions. Phycobilin pigment production was significantly affected by irradiance, nutrient concentration, and culture duration. For Porphyra abbottiae V. Krishnam., Porphyra sp., and Porphyra torta V. Krishnam., maximal phycoerythrin (63.2–95.1 mg · g dwt?1) and phycocyanin (28.8–64.8 mg · g dwt?1) content generally occurred at 10 μmol photons · m?2 · s?1, f/4–f/2 nutrient concentration after 10–20 d of culture. Whereas for Porphyra hiberna S. C. Lindstrom et K. M. Cole, the highest phycoerythrin (73.3 mg · g dwt?1) and phycocyanin (70.2 mg · g dwt?1) content occurred at 10 μmol photons · m?2 · s?1, f nutrient concentration after 60 d in culture. Under similar conditions, the different species showed significant differences in pigment content. P. abbottiae had higher phycoerythrin content than the other three species, and P. hiberna had the highest phycocyanin content. P. torta had the lowest phycobilin content. 相似文献