Quantification Of Total Phenolic Content Research Articles

Antioxidant activity and total phenolic and flavonoids content variations of leaves extracts of white Horehound (Marrubium vulgare Linné) from three geographical origins.

To elucidate the effect of the sampling location of Marrubium vulgare L.leaves on phenolic contents and antioxidant proprieties of flavonoids extracts. M.vulgare L.leaves were collected from three different geographical locations belonging to northwest Algeria: Tessala (mountain region), M'sila forest (coastal region), and Ain Skhouna (steppe region). The flavonoid extraction was achieved using organic solvents with different polarities (methanol, chloroform, ethyl acetate, and hexane). Folin-Ciocalteu colorimetric method was used for quantification of total phenolic contents, and aluminum chloride assay for quantification of total flavonoid contents. The antioxidant properties of flavonoids extract were studied by free l,l-diphenyl-2-picrylhydrazyl radical-scavenging technique. Total phenolic and flavonoids concentrations varied respectively between 40.7 and 160mg gallic acid equivalents/g and 27.4 and 66.3mg catechin equivalents/g. The DPPH free radical-scavenging activity shows that the antioxidant activity of the flavonoid extracts varied significantly (P<0.001) depending on the type of the organic solvent used, and the sampling location. The methanol, chloroform and ethyl acetate extracts exhibited the highest percentages of inhibition unlike to the aqueous and hexane extracts. These percentages are ranged from 54.8 to 98.8% at 1000μg/mL. In general, M'sila forest flavonoids extracts showed the highestfree radical inhibition capacity; followed by those of Ain Skhouna and Tessala Mountain. The inhibitory concentration 50 (IC50) ranged from 33.7 to 774μg/mL and often exceeded those recorded by phenolic standards (ascorbic acid, gallic acid, caffeic acid, tannic acid and catechin). The phytochemical screening revealed the presence of some flavonoid classes, such as flavans and flavanols. The results suggested a potent antioxidant activity of M.vulgare flavonoids extracts, which may find its application in feature research for the food and the pharmacological industries.

Bioactive extracts of red seaweeds Pterocladiella capillacea and Osmundaria obtusiloba (Floridophyceae: Rhodophyta) with antioxidant and bacterial agglutination potential.

To evaluate the antioxidant, antibacterial and bacterial cell agglutination activities of the hexane (Hex) and 70% ethanol (70% EtOH) extracts of two species of red seaweeds Pterocladiella capillacea (P.capillacea) and Osmundaria obtusiloba. Invitro antioxidant activity was determined by DPPH radical scavenging assay, ferric-reducing antioxidant power assay, ferrous ion chelating assay, β-carotene bleaching assay and total phenolic content quantification. Antimicrobial activity was tested using the method of disc diffusion on Mueller-Hinton medium. The ability of algal extracts to agglutinate bacterial cells was also tested. The 70% EtOH extract of the two algae showed the highest values of total phenolic content compared to the Hex extract. The results of DPPH for both extracts (Hex, 70% EtOH) of Osmundaria obtusiloba (43.46% and 99.47%) were higher than those of P.capillacea (33.04% and 40.81%) at a concentration of 1000μg/mL. As for the ferrous ion chelating, there was an opposite behavior, extracts of P.capillacea had a higher activity. The extracts showed a low ferric-reducing antioxidant power, with optical density ranging from 0.054 to 0.180. Antioxidant activities of all extracts evaluated for β-carotene bleaching were above 40%. There was no antibacterial activity against bacterial strains tested. However, the extracts of both species were able to agglutinate bacterial Gram positive cells of Staphylococcus aureus and Gram negative cells of Escherichia coli, multidrug-resistant Salmonella and Vibrio harveyi. This is the first report of the interaction between these algal extracts, rich in natural compounds with antioxidant potential, and Gram positive and Gram negative bacterial cells.

Quantification of Total Phenolic Content, HPLC Analysis of Flavonoids and Assessment of Antioxidant and Anti-haemolytic Activities of Hibiscus rosa-sinensis L. Flowers in vitro

Quantification of Total Phenolic Content, HPLC Analysis of Flavonoids and Assessment of Antioxidant and Anti-haemolytic Activities of Hibiscus rosa-sinensis L. Flowers in vitro

Microplate Quantification of Total Phenolic Content from Plant Extracts Obtained by Conventional and Ultrasound Methods

There is increasing interest in phenolic compounds around the world because of their potential positive impact on human health. Phenolic compounds are largely found in fruits and vegetables. Extraction of phenolic compounds is a very important step in their recovery. The newly developed technique of ultrasound-assisted extraction (UAE) appears to be an advantageous alternative compared with conventional techniques, because it is simple and environmental friendly. The potential of UAE needs to be evaluated in each plant in order to demonstrate its efficiency. The objective of the present study was to compare a conventional method and UAE on the extraction efficiency of phenolic compounds from Jatropha dioica, Fluorensia cernua, Turnera diffusa and Eucalyptus camaldulensis plants and evaluate the in vitro anti-oxidant potential. Validation of the new method was carried out using mixed-model methodology and regression analysis. Feasibility of this new method was shown and applied using several plants extracts obtained by different extraction methods from semi-arid Mexican plants, which were characterised by high levels of polyphenols. Additionally, the anti-oxidant potential of these extracts was determined by 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity. Results showed that the new microplate method can be used to determine total phenolic content in plant extracts. Additionally, an alternative extraction method by ultrasound was less efficient compared with the conventional method. The tested plants are good candidates to obtain nutraceuticals and functional food ingredients.

Antioxidant and antimicrobial potential of the Bifurcaria bifurcata epiphytic bacteria.

Surface-associated marine bacteria are an interesting source of new secondary metabolites. The aim of this study was the isolation and identification of epiphytic bacteria from the marine brown alga, Bifurcaria bifurcata, and the evaluation of the antioxidant and antimicrobial activity of bacteria extracts. The identification of epiphytic bacteria was determined by 16S rRNA gene sequencing. Bacteria extracts were obtained with methanol and dichloromethane (1:1) extraction. The antioxidant activity of extracts was performed by quantification of total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and oxygen radical absorbance capacity (ORAC). Antimicrobial activities were evaluated against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Salmonella enteritidis, Staphylococcus aureus, Saccharomyces cerevisiae and Candida albicans. A total of 39 Bifurcaria bifurcata-associated bacteria were isolated and 33 were identified as Vibrio sp. (48.72%), Alteromonas sp. (12.82%), Shewanella sp. (12.26%), Serratia sp. (2.56%), Citricoccus sp. (2.56%), Cellulophaga sp. (2.56%), Ruegeria sp. (2.56%) and Staphylococcus sp. (2.56%). Six (15.38%) of the 39 bacteria Bifurcaria bifurcata-associated bacteria presented less than a 90% Basic Local Alignment Search Tool (BLAST) match, and some of those could be new. The highest antioxidant activity and antimicrobial activity (against B. subtilis) was exhibited by strain 16 (Shewanella sp.). Several strains also presented high antimicrobial activity against S. aureus, mainly belonging to Alteromonas sp. and Vibrio sp. There were no positive results against fungi and Gram-negative bacteria. Bifurcaria bifurcata epiphytic bacteria were revealed to be excellent sources of natural antioxidant and antimicrobial compounds.

Qualitative and Quantitative Determination of Secondary metabolites and Antioxidant Potential of Eruca sativa

Objective: To Determine the phytochemical composition of E. sativa (stem, leaves, flowers and seeds), and evaluate their antioxidant activity. Method: Preliminary phytochemical screening for all parts of E. sativa (stem, leaves, flowers and seeds) was carried out according to standard methods. Total phenolic contents of all methanolic extracts of E. sativa, have been quantified spectrophotometrically. Hydrogen Peroxidase and 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical assays have been used to analyze antioxidant characteristics of all extracts of E. sativa (leaves, stem, seed, flowers and seeds). Further separation and identification of number of phenolic compounds has been carried out by Reversed- Phase High-Performance Liquid Chromatography (RP-HPLC). Results: Experimental evaluation indicated that E. sativa is a rich source of secondary phytoconstituents (Alkaloids, flavonoids, Diterpenes, Coumarins, polyphenols, tannins, cardiac glycosides etc). Quantification of total phenolic contents from all aerial parts revealed that they contain significant amount of phenolics particularly seeds and leaves (27.1 ± 0.2 mg, 23.07 ± 0.11GAE/g) respectively. Searation and identification of phenolics from E. sativa stem, leaves, flowers and seeds extracts through RP-HPLC showed presence of variety of important phenolics namely; Vanillin (RT=3.853), Ellagic acid (RT=4.04), Salicylic acid (RT=19.09), Resorcinol (RT=3.30), Catechol (RT=3.53), Quercetin (RT=18.91), Benzoic acid (RT=10.4), Tannic acid (RT=5.06), Kaempferol (RT=8.70) and Rutin (RT=9.2). Conclusion: Results revealed that E. sativa is a rich source of secondary phytoconstituents which impart significant antioxidant potential. This work also contributes significantly to support the claim about the use of this herb in folk medicines. Further investigation regarding isolation and purification of a number of phytoconstituents from leaves, stem, flowers and seeds of E. sativa may yield optimal combinations of therapeutic alternates.

Antioxidant, Antimicrobial and Cytotoxicity Activities of Acacia farnesiana (L.) Willd. Leaves Ethanolic Extract

The antioxidant activity was evaluated from the ability to chelate iron, reducing property, scavenging DPPH radical and nitric oxide. The A. farnesiana ethanolic extract responded to all the antioxidant assays in concentrations dependent manner. Evaluated by broth microdilution assay, the extract exhibited MIC value at 0.8 mg/ml against Bacillus subtilis and MIC value at 2.5 mg/ml against Saccharomyces cerevisiae. The absence of cytoxicity was observed from the brine shrimp lethality test. The quantification of total phenolic content by Folin-Ciocalteu reagent resulting 209.78 ± 3.21 mg gallic acid/g ethanolic extract of A. farnesiana leaves. Analysis of the extract by both HPLC-PDA and LC/MS have tentatively identified flavonoid galloylglycoside and flavonoid glycosides from the extract. It was plausible that the preparation method of the extract influenced the consituents of the extract, and that later contributed to the exhibited antioxidant and antibacterial activities. Quercetin deoxyhexoside was tentatively identified as the major consituent of the extract. Bioassay guided isolation is suggested as future research to study the biological activities and elucidate the chemical structure of flavonoids involved.