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The effect of tropospheric ozone on flavonoids and pigments content in common buckwheat cotyledons

Abstract

Tropospheric ozone forms in photochemical reactions or by refuse burning and combustion of exhaust gases from engines, and during some industrial processes. The mean ambient ozone concentration doubled during the last century, and in many urban areas has reached the phytotoxic level. In the present study, there was determined the effect of ozone fumigation on levels of individual flavonoids, chlorophylls, carotenoids and total phenols in the cotyledons of four common buckwheat cultivars (Hruszowska, Panda, Kora and Red Corolla). Six-day-old buckwheat seedlings were grown in controlled conditions and treated with an elevated dose of ozone (391 μg · m−3) during 5 days for 1 h each day. After the experiment, the cotyledons of the seedlings were analysed for individual flavonoids, chlorophylls, carotenoids and total phenols. Shoot elongation was also measured. Individual types of flavonoids in buckwheat cotyledons were found to respond to an elevated ozone dose in various ways. The response was also dependent on the cultivar evaluated. In the cotyledons of ozonized buckwheat seedlings, contents of C-glucosides of luteolin and apigenin decreased or did not change depending on the cultivar examined. In the case of flavonols, the contents of quercetin-3-O-rhamnosyl-galactoside and rutin (quercetin-3-O-rhamnosyl-glucoside) were markedly reduced in most cultivars. O3 had no effect on the level of anthocyanins and chlorophylls but it decreased carotenoids, and tended to inhibit buckwheat growth. In conclusion, a thesis can be formulated that, due to high reduction in important flavonoids, an elevated level of ambient ozone decreases the nutritional value of common buckwheat seedlings.

Open access
Phenolic Compounds and Seed Oil Composition of Ziziphus mauritiana L. Fruit

Phenolic Compounds and Seed Oil Composition of Ziziphus mauritiana L. Fruit

Ber is a tropical fruit which grows from the tree species, Ziziphus mauritiana Lamk. The pericarp of this fruit is consumed either fresh or dried while its seeds are usually discarded as waste. The present study was undertaken to evaluate the antioxidant activity and phenolic content of the fruit, and to evaluate if any potential value-added phytochemicals can be extracted from seed waste. The edible portion of the fruit was extracted with 60% aqueous methanol by sonication and then assayed for total phenolic content, antioxidant activity, and individual phenolic compounds by HPLC-DAD. The seed oil extracted with n-hexane was assayed for fatty acid composition, sterols, and tocopherols content by GC-MS. The total phenolic content of the fresh fruit was 12.8 mg/g as gallic acid equivalent, with an antioxidant activity of 0.5 μmol/g as quercetin equivalent by Folin-Ciocalteu and DPPH assays respectively. Hydroxybenzoic acid, vanillin, ortho- and para-coumaric acid, epicatechin, quercetin, and naringenin were tentatively identified by matching retention time and UV spectra with those of commercial reference standards. GC-MS analysis of the TMS derivative of fruit extract showed the presence of following compounds: propanoic, hexanoic, heptanoic, octanoic, nonanoic, decanoic, dodecanoic, n-pentadecanoic, hexadecanoic, benzoic, and trihydroxybenzoic acids. In addition, D-fructose, galactofuranoside, gluconic acid, and β-sitosterol were also detected. In seed oil of ber, the fatty acids such as, hexanoic, octanoic, 7-octadecenoic, 9,12-octadecendoic, eicosanoic, 11-eicosenoic, and docosanoic acid with 7-octadecenoic acid, were found to make up 55% of total fatty acids. Squalene, γ-tocopherol and stigmasterol were identified as minor constituents in the unsaponifiable fraction of seed oil. Current study shows that ber fruit is a good source of healthy phytochemicals.

Open access
Determination of Bioactive Compounds and Mineral Substances in Latvian Birch and Maple Saps

Abstract

Birch and maple saps contain carbohydrates and organic acids, B complex vitamins and vitamin C, tannins, flavonoids, glycosides and mineral substances. The aim of the study was to quantitatively determine the concentrations of bioactive compounds and mineral substances in Latvian birch (Betula pendula Roth.) and maple (Acer platanoides L.) saps. Electrical conductivity was determined (629 and 967 S/cm in birch and maple saps, respectively) to characterise the total amount of mineral substances. In birch and maple saps the titratable acidity (0.50 and 0.70 mmol of NaOH per litre of sap, respectively) and formol number (0.25 and 0.20 mmol NaOH per litre of sap, respectively) were determined. The protein concentration was found to be higher in maple sap (171 and 127 mg/l, respectively). The antioxidant concentration, determined using quercetin as a standard, was 0.35 mg of quercetin equivalents (QE)/l in birch sap and 0.77 mg QE/l in maple sap. In conclusion, Latvian maple sap contains more bioactive and mineral compounds than birch sap. Latvian birch sap contains up to 20% more glucose and fructose than birch sap produced in Finland, but Latvian maple sap contains 10 to 40% less sucrose than sap produced in North America.

Open access
Maidenhair tree (Ginkgo Bilobae) leaf extraction products in the light of Biopharmaceutics Classification System (BCS) requirements and medium of diversified polarity (εM)

Summary

Model maidenhair tree (Ginkgo bilobae) leaf extracts were created basing on medium of diversified polarity (εM). Chromatographic analysis was performed with the HPLC method, with the so-called dry residue remaining after evaporating the dissolving agent from saturated aqueous solutions and from 0.1 mol HCl. Viscosity measure and surface activity estimations were conducted on phase boundary. Then, basic values of viscosity ([η], Mη) and hydrodynamic values (Ro, Robs., Ω) were calculated. Moreover, reference quercetin and rutin (rutoside) were used to mark the conversion contents of flavonoids in produced extracts with the UV method.

Open access
Phenolic compounds variation in Mentha L. Species in the course of a four-years period / Kolísanie fenolových látok v rôznych druhoch Mentha L. Počas 4 ročného obdobia

Abstract

Mints rank among the most important Lamiaceae plants. In addition to essential oil, they contain many valuable phenolic compounds, including flavonoids and phenolic acids that participate in mints’ pharmacological properties. In this work, we examined the contents of phenolic compounds variation in the course of 4 years of vegetation. We compared the contents of total hydroxycinnamic derivatives expressed as rosmarinic acid (λ = 505 nm), total polyphenols and tannins expressed as rosmarinic acid (λ = 760 nm), and flavonoids expressed as luteolin-7-O-glucoside (λ = 392 nm) and quercetin (λ = 420 nm) in 1-, 2-, 3-, and 4-year-old plants’ dry leaves, respectively. Spectrophotometric methods of the European Pharmacopoeia were employed. Our results show high levels of active phenolic compounds, particularly in 3- and 4-year-old plants.

Open access
Phenolics in the Tussilago farfara leaves

Summary

Coltsfoot leaves (Farfarae folium) are used in the European medicine in respiratory tract diseases, for cough, bronchitis and asthmatic disorders, while in the traditional Chinese medicine only flower buds (Farfarae flos) have been recognized as a medicine. A short literature review shows that most data concern the chemical composition of the coltsfoot flowers. During the carried out studies we have isolated and identified (UV, 1H and 13C NMR, analysis of acid and enzymatic hydrolyze products) six known flavonols from the coltsfoot leaves: kaempferol and its 3-O-β-glucopyranoside and 3-O-α-rhamnopyranosyl(1→6)- β-glucopyranoside, along with quercetin derivatives: 3-O-β-arabinopyranoside, 3-O-β- glucopyranoside and 3-O-α-rhamnopyranosyl(1→6)-β-glucopyranoside. Moreover, we have detected the presence of three phenolic acids.

Open access
Botanical Investigation of Fallopia Dumetorum (L.) Holub (Polygonaceae) and Qualitative and Quantitative Assessment of its Polyphenolic Compounds

Abstract

Background: Considering the continuous need to find new sources of polyphenolic compounds, we performed a pharmacognostical examination of the species Fallopia dumetorum (L.) Holub sin. Polygonum dumetorum L. (Polygonaceae). The plant is common in the plain regions of Romania and has not been exploited therapeutically.

Materials and method: Microscopic examination was performed on cross-sections, surface preparations and on powder obtained from the aerial parts of the flowering plant. Qualitative chemical analysis was realized by phytochemical screening and thin layer chromatography (TLC). Phenolic compounds were assayed by spectrophotometric methods: flavonoids expressed as rutin (with aluminium chloride), phenolcarboxylic acids expressed as chlorogenic acid (Arnow’s method) and proanthocyanidins expressed as cyanidin chloride (in acidic medium, by conversion to anthocyanins).

Results: The species has the following microscopic characters: anomocytic stomata, druses of calcium oxalate, sessile, pluricellular glandular hairs and pollen grains with smooth exine. Polysaccharides, reducing compounds, coumarins, sterols/triterpenes, phenol-carboxylic acids, flavones, proanthocyanidins, tannins and carotenoids were identified by phytochemical screening; chlorogenic acid, caffeic acid, quercetin and stigmasterol/beta-sitosterol were detected by TLC. F. dumetori herba has a content of 1.49 ± 0.105 g% polyphenol-carboxylic acids, 0.40 ± 0.087g% flavonoids and 0.18 ± 0.002 g% proanthocyanidins.

Conclusions: We have characterized pharmacognostically the native species F. dumentorum. Due to its content in phenolic compounds it might serve as a source of polyphenols.

Open access
Inhibition of Filarial Glutathione-S-transferase by various classes of compounds and their evaluation as novel antifilarial agents

Abstract

Glutathione S-transferase(s); GST(s) (E.C. 2.5.1.18) are a large family of multifunctional dimeric enzymes that conjugate reduced glutathione to electrophilic centres in hydrophobic organic compounds. GST(s) represent the major class of detoxifying enzymes from parasitic helminths. The GST enzymatic activity has been described in the adult and larval stages of helminths. Several forms and isoforms of the enzyme have been purified and GST genes have also been isolated and expressed as recombinant proteins. The helminth GST(s) participate in detoxification of lipid hydroperoxides and cytotoxic carbonyl compounds produced by oxygen-reactive intermediates (ORIs). The ORIs can come from the endogenous parasite metabolism or from the host immune system. The helminth GST(s) are able to conjugate glutathione to xenobiotic compounds or to bind to the anthelminth drugs. GST is usually found to be localized near to host-parasite interface. This enzyme has been identified as a potentially vulnerable target in immunotherapy and chemotherapy of parasitic diseases. The most effective drug candidates are those based on inhibitors of GST. In the present study, purified GST from cytosolic fraction of bovine filarial worms Setaria cervi was inhibited in a concentration dependent fashion by various compounds such as hemin, ethacrynic acid, S-hexylglutathione, quercetin, cibacron blue, lithocholate sulfate and ellagic acid. Cytosolic GST was inhibited to varying degrees by each inhibitor. In this context, the possible physiological significance of the observed results has been discussed.

Open access
Determination of Antioxidant Capacity, Flavonoids, and Total Phenolic Content in Eucalyptus and Clover Honeys

Abstract

Polyphenolic compounds reportedly produce physiological effects that are beneficial to health. Bee products are particularly rich in polyphenolic compounds. We determined the antioxidant capacity and the phenolic and flavonoid compounds content of 81 samples of honey. We used the Folin-Ciocalteu reagent method to evaluate the total phenolic content. The antioxidant activities were evaluated using in vitro scavenging assays of 2,2-diphenyl-1-picrylhydrazyl (DPPH ) and hydroxyl radicals (OH ), Trolox equivalent antioxidant capacity (TEAC ), and ferric-reducing antioxidant capacity (FRAC ). Total phenolic content ranged from 40.3 to 193.0 mg gallic acid equivalents (GAE )/100 g; the flavonoid content varied from 1.4 to 7.5 mg quercetin equivalents (QE)/100 g. Eucalyptus honeys exhibited significantly higher phenolic content and free radical-scavenging activity than clover honey samples (p<0.05 for all). Principal component analysis explained 73% of the differences observed in antiradical activity with respect to floral origin. Total phenolic content may be more useful than the radical-scavenging assay for detecting antioxidant capacity in honey; it also represents the variable that most appropriately discriminated among these honeys.

Open access
Application of HPLC-DAD Technique for Determination of Phenolic Compounds in Bee Pollen Loads

Abstract

A method was elaborated to determine phenolic compounds (vanillin, caffeic, p-coumaric and salicylic acids, and flavonoids: rutin, hesperetin, quercetin, pinocembrin, apigenin, kaempferol, isorhamnetin, chrysin, and acacetin) in bee pollen loads using highperformance liquid chromatography with a diode array detector (HPLC-DAD). Phenolic compounds from bee pollen were isolated on Cleanert C18-SPE columns (500 mg/6 mL, Agela Technologies). Polyphenols were identified by comparing the retention times and spectra of compounds found in pollen load samples with the ones of the standard mixture. Quantitative analysis was conducted using the external standard method. In addition, basic validation parameters for the method were determined. For the identified compounds (except for the salicylic acid), satisfactory (≥0.997) linear correlations were obtained. The elaborated method showed high repeatability and inter-laboratory reproducibility. Variability coeffcients of the majority of phenolic compounds did not exceed 10% in conditions of repeatability and inter-laboratory reproducibility, and for the total polyphenolic content they were 1.7 and 5.1%, respectively. The pollen load samples (n = 15) differed in qualitative and quantitative composition of the phenolic compounds. In all the samples, we identified the p-coumaric and salicylic acids and flavonoids rutin, hesperetin, and apigenin nevertheless, these compounds’ contents significantly differed among individual samples. The total phenolic content in the tested samples of pollen loads ranged from 0.653 to 5.966 mg/100 g (on average 2.737 mg/100 g).

Open access