Phosphomolybdenum Method Research Articles

Screening of Antioxidant, Antimicrobial Activities and Chemical Contents of Edible Mushrooms Wildly Grown in the Black Sea Region of Turkey

The antioxidative activity of the methanol extracts obtained from twelve commonly consumed wild edible mushrooms was investigated according to the phosphomolybdenum method, inhibition of linoleic acid peroxidation, reducing power, metal chelating, O(2)(˙-), DPPH(˙), peroxide and H(2)O(2) scavenging activity in the Black Sea Region of Turky, and compared to standard antioxidant compounds such as a-tocopherol, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and trolox. Total phenolic compounds, flavonoids, anthocyanins, ascorbic acid, β-carotene and lycopene in the extracts were measured. The antimicrobial activities of extracts were also evalated against gram (-) and (+) bacteria and yeast with disc diffusion method. Hydnum repandum, Lactarius delicious, Lactarius camphoratus, Lactarius piperatus, Ramaria flava, and Agaricus bisporus were greater than α-tocopherol and BHT on antioxidant activity. The lipid peroxidation of L. camphoratus and Lactarius volemus was excellent, and was 58.05% and 61.44% respectively. The DPPH(˙) scavenging effects decreased in the order of R. flava>BHT> Macrolepiota procera>L. camphoratus>L. piperatus>Lactarius volemus>a-tocopherol and were, at 500 µg/ml and were 80.38, 76.61, 69.74, 61.55, 61.47, 61.09, 60.65%, respectively. All the extracts of mushroom also had the stronger chelating effect according to standards. The O(2)(˙-) scavenging effect of extracts of the mushroom species was in order of R. flava>Boletus edulis>Leatiporus sulphureus>M. procera>standards. L. piperatus, L. camphorates, L. volemus, A. bisporus, Chanterellus cibarius, L. sulphureus, H. repandum showed strong antimicrobial activity, especially on E. coli. H. repandum exhibited to be more effective on P. aeruginosa than other bacterial strains.

Antioxidant activity and free radical-scavenging capacity of Gynura divaricata leaf extracts at different temperatures

Background:Extraction temperature influences the total phenolic content (TPC), total flavonoid content (TFC) of medicinal plant extracts to a great extend. TPC and TFC are the principle activity constituents present in the plant. The effects of extraction temperature on TPC, TFC and free radical-scavenging capacity of Gynura divaricata leaf extracts are worth to study.Materials and Methods:Folin–Ciocalteu and aluminum chloride colorimetric assay were used to determine the TPC and TFC of Gynura divaricata leaf extracts at different temperatures. The antioxidant and free radical-scavenging activity were measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) and phosphomolybdenum methods.Results:TPC and TFC were significantly elevated with increasing extraction temperature (from 40°C to 100°C). However, TPC and TFC were not significantly different (P > 0.05) at the extraction temperatures 90°C and 100°C. Also, the extracts obtained at a higher temperature exhibited a significant free radical-scavenging activity compared with extraction at lower temperatures (P < 0.05). The TPCs (13.95-36.68 mg gallic acid equivalent/g dry material) were highly correlated with DPPH (R2 = 0.9229), ABTS (R2 = 0.9951) free radical-scavenging capacity, and total antioxidant activity (R2 = 0.9872) evaluated by phosphomolybdenum method.Conclusion:The TPC and TFC of G. divaricata leaf was significantly influenced by the extraction temperatures, which were the main antioxidant constituents present in the G. divaricata plant.

RP-HPLC–DAD analysis of phenolic compounds in pomace extracts from five grape cultivars: Evaluation of their antioxidant, antiradical and antifungal activities in orange and apple juices

Phenolic compounds, related to antioxidative and antifungal properties of ethanolic extracts from five commercial grape cultivars (three red and two white) grown in Turkey were determined. A reversed-phase high performance liquid chromatography (RP-HPLC) procedure was developed, and a total 18 different phenolic compounds were identified. Total phenolic contents of the extracts were determined using Folin–Ciocalteau method. Antioxidant activities of the extracts were evaluated by using DPPH radical scavenging and phosphomolybdenum methods. All extracts exhibited strong antioxidant and antiradical activity. Phenolic compounds and antioxidant activities of the extracts were variety dependent. Antifungal activities of the pomaces and extracts were screened by both in vitro agar-well diffusion assay and antifungal activity in apple and orange juices in situ using Zygosaccharomyces rouxii and Z. bailii. Antifungal activities revealed that the pomaces and extracts of Gamay and Kalecik karasi could be more effective antifungal agents than those of Emir, Narince and Okuzgozu grape cultivars.

Synthesis and Antioxidant Activity of Some New Coumarinyl-1,3-Thiazolidine-4-ones

A series of Schiff’s bases (E)-N-2-aryliden-2-(4-methyl-2-oxo-2H-chromen-7-yloxy)acetohydrazides 2a-l and N-(2-(substituted phenyl)-4-oxo-thiazolidin-3-yl)-2-(4-methyl-2-oxo-2H-chromen-7-yloxy)acetamides 3a-l were synthesized and evaluated for their antioxidant activity by the phosphomolybdenum method. Most of the Schiff’s bases and thiazolidine-4-ones bearing two hydroxyl groups on the phenyl ring showed excellent antioxidant activity in comparison with ascorbic acid. Preliminary investigation on cytotoxic and antifungal activity was done on some representative samples.

A comparative study on the antioxidant activity of methanolic leaf extracts of Ficus religiosa L, Chromolaena odorata (L.) King & Rabinson, Cynodon dactylon (L.) Pers. and Tridax procumbens L.

Objective To compare the antioxidative effects of the methanolic leaf extracts of Ficus religiosa (F. religiosa), Chromolaena odorata (C. odorata), Cynodon dactylon (C. dactylon) and Tridax procumbens (T. procumbens) as well as the contents of antioxidants in the extracts. Methods Total phenol and total flavanoid contents were measured according to the standard procedures. The total antioxidant capacity was determined using the phosphomolybdenum method. Reducing power was determined by the potassium ferricyanide reducing method. The free radical scavenging activity was measured by 2,2′-Diphenyl-1-picrylhydrazyl (DPPH) assay. Results Quantitative phytochemical analysis of total phenol content showed that C. odorata had the highest content of phenolic compounds significantly followed by F. religiosa, T. procumbens and C. dactylon. As for the total flavanoids content, F. religiosa had the highest content, followed by C. odorata, T. procumbens and C. dactylon. Study on the total antioxidant capacity revealed that F. religiosa, C. dactylon and C. odorata showed higher total antioxidant capacity. T. procumbens showed the lowest capacity. Meanwhile, T. procumbens and C. odorata have the highest reducing power activity followed by F. religiosa and C. dactylon. The results of DPPH radical scavenging activity indicated that T. procumbens induced the largest elevation as the concentration of its extract increased, followed by C. odorata and F. religiosa and C. dactylon. Conclusions The present study demonstrates the antioxidative capacity of all the four plant species. Of all the plants, C. odorata, a perennial weed plant showed potentially a high antioxidant activity, with higher phenolic and flavonoids contents. The data suggest that C. odorata can be best utilized in developing bioantioxidants.

An efficient synthesis and antioxidant properties of novel imino and amino derivatives of 4-hydroxy coumarins

Series of imino and amino derivatives of 4-hydroxy coumarins were synthesized via conventional and microwave promoted procedure and evaluated for antioxidant potential through different in vitro models such as (DPPH) free radical scavenging activity, linoleic acid emulsion model system, reducing power assay and phosphomolybdenum method. All prepared compounds possess good antioxidant activity and among them p-nitro-phenyl derivative 6c with IC50 at 25.9 microM possesses radical scavenging activity which is comparable to standard BHT, while the best reducing power was observed in a case of benzyl amino compound 8c (RP50 255.6 microM). Also, observed data indicated that compounds may serve as inhibitors of lipid peroxidation process.

Chemical composition and screening of the antimicrobial and anti-oxidative activity of extracts of Stachys species

GC and GC/MS analyses of the diethyl ether and ethyl acetate extracts obtained from the aerial parts of Stachys germanica subsp. heldreichii (Boiss) Hayek, Stachys iva Griseb., Stachys plumosa Griseb. and Stachys scardica Griseb., Balkan peninsula endemics, were performed. One hundred and seventy-nine constituents, accounting for 88.8-98.1% of the total composition of the extracts, were identified. The common feature of the diethyl ether extracts was the high content of terpenoids and fatty acidderived compounds, while the common feature of the ethyl acetate extracts was the prevalence of fatty acid-derived compounds. A disk diffusion method was used for the evaluation of the antimicrobial activities of the extracts against a panel of microorganisms (bacteria: Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Salmonella enteritidis; fungi: Aspergillus niger and Candida albicans). The total antioxidant capacity of the extracts was evaluated by the phosphomolybdenum method. The preliminary bioassay results indicated that the diethyl ether extract of S. plumosa could be a possible source of antioxidant and antimicrobial compounds.

In vitro anti-oxidant activity of the leaves of Dillenia indica

The methanol extract of Dillenia indica was tested for antioxidant activity as determined by free radical scavenging of DPPH radical scavenging assay, reducing power, total antioxidant capacity measured by phosphomolybdenum method, total phenolic content and total flavonoids content determination assays. The extract showed significant activities in all antioxidant assays compared to the standard antioxidant in a dose dependent manner. In DPPH radical scavenging assay the <TEX>$IC_{50}$</TEX> value of the extract was found to be 100.53<TEX>${\mu}g/ml$</TEX> while ascorbic acid has the <TEX>$IC_{50}$</TEX> value 58.92<TEX>${\mu}g/ml$</TEX>. Dillenia indica extract showed strong reducing power and total antioxidant capacity. Moreover, methanol extracts also possess high amount of phenolics and flavovonoids and expressed as gallic acid and rutin equivalent respectively. The remarkable activities exhibited in reactive oxygen species scavenging may attributed to the high amount of hydrophilic phenolics present in Dillenia indica.

Antioxidant activity of wild edible plants in the Black Sea Region of Turkey

The antioxidative activity of the 80% ethanol extract obtained from eleven commonly consumed wild edible plants was determined according to the phosphomolybdenum method, reducing power, metal chelating, superoxide anion and free radical scavenging activity and compared to standard compounds such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and trolox. Total phenolic compounds, flavonoids, and anthocyanins in the extracts were also measured. Trachystemon orientalis, Vaccinium mrytillus, Rumex acetosella Polygonum amphibium, Beta vulgaris, and Similax Excelsa had the highest antioxidant capacities. Overall results showed that these plants can serve as good sources of bioactive polyphenols in the human diet and can be regarded as good candidates for nutritional supplement formulations due to their high concentrations of total phenolic compounds, flavonoids and anthocyanins as well as their strong antioxidant activity.

Substituted imino and amino derivatives of 4-hydroxycoumarins as novel antioxidant, antibacterial and antifungal agents: Synthesis and in vitro assessments

A series of imino and amino derivatives of 4-hydroxycoumarins were synthesised and evaluated for antioxidant potential, through different in vitro models such as (DPPH) free radical-scavenging activity, linoleic acid emulsion model system, reducing power assay and phosphomolybdenum method. Also, antimicrobial activity of obtained coumarins was evaluated against 13 bacteria and eight fungi. All prepared compounds possessed good antioxidant activity and among them a p-nitrophenol derivative with IC 50 at 25.9 μM possessed radical-scavenging activity which was comparable to BHT. Observed data for antibacterial activity indicated strong activity of all tested amino derivatives, while imines showed better antifungal properties.

Composition, Antioxidant and Antimicrobial Activities of the Essential Oil of Marrubium deserti

The essential oil from aerial part of Marrubium deserti De Noé (Lamiaceae), obtained by hydrodistillation was analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS), and evaluated for in vitro antimicrobial activity. The antioxidant activity was determined using three in vitro assays: scavenging effect on DPPH, the ABTS test and the phosphomolybdenum method. Thirty-seven compounds were identified in the oil, with germacrene D as the major component (45.7%). This oil was characterized by an important hydrocarbon fraction (78.1%) and by the predominance of sesquiterpenes (67.4%). M. deserti essential oil had no activity on the tested microorganisms (Staphylococcus aureus ATCC 25923, Echerichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Candida albicans and Aspergillus flavus). However the oil presented an antioxidant activity.

Free radical scavenging and antioxidant activities of Glinus oppositifolius (carpet weed) using different in vitro assay systems

Glinus oppositifolius (L.) Aug. DC. (Aizoceae), commonly called slender carpet weed, is a prostrate or diffuse herb which acts as stomachic, uterine stimulant, aperient and lochia. It is used traditionally in the treatment of earache, itch and skin diseases. Glinus oppositifolius was extracted with ethanol (70%) and used for the evaluation of various in vitro antioxidant assays which includes H-donor activity, nitric oxide scavenging, superoxide anion scavenging, reducing ability, hydroxyl radical, hydrogen peroxide scavenging, total phenolic content, total flavonoid content, total antioxidant activity by thiocyanate and phosphomolybdenum method, metal chelating, β-carotene bleaching, total peroxy radical assays. The pro-oxidant activity was measured using bleomycin-dependent DNA damage. Ex vivo models such as lipid peroxidation were used to study the antioxidant property of the extract. The various antioxidant activities were compared with suitable standard antioxidants such as ascorbic acid, butylated hydroxyl toluene (BHT), α-tocopherol, curcumin, quercetin and Trolox. The generation of free radicals, viz., O2·−, OH·, H2O2, NO· and peroxyl radicals, were effectively scavenged by the ethanol extract of Glinus oppositifolius. The antioxidant activity depends on concentration and increases with increasing amounts of the extract. The total phenolic content, flavonoid content and total antioxidant activity in Glinus oppositifolius were determined as microgram (μg) pyrocatechol, quercetin and α-tocopherol equivalent/mg, respectively. The extract did not exhibit any pro-oxidant activity when compared with ascorbic acid. The results obtained in this study indicate that Glinus oppositifolius scavenges free radicals and reduces lipid peroxidation, ameliorating the damage imposed by oxidative stress in different disease conditions and serve as a potential source of natural antioxidant.

In Vitro Evaluation of the Antioxidant Activities of Grape Seed (Vitis vinifera) Extract, Blackseed (Nigella sativa) Extract and Curcumin

Abstract Objective Evaluation of in vitro antioxidant activities of grape seed (Vitis vinifera) extract GSE, blackseed (Nigella sativa) extract NSE and curcumin CUR. Methods In vitro antioxidative potential of GSE, NSE and CUR was evaluated through determination of total soluble phenolic content and reducing power. Also, the antioxidant activity was measured using linoleic acid peroxidation assay, phosphomolybdenum method, superoxide anion radical scavenging assay and DPPH. free radical-scavenging assay. Results GS and NS were extracted with 50% ethanol and methanol, respectively. Extraction yield of GSE and NSE was 127 and 109 mg/g dry weight, respectively. CUR elicited greater phenolic contents (115±0.04) than NSE (14±0.05) and GSE (5.2±0.06) mgGAE/g. Percentage scavenging activity of each sample against DPPH. was 1425%, 600% and 333% for CUR, NSE and GSE, respectively. Percentage superoxide scavenging activity was more pronounced in CUR (41%) than NSE (32%) and GSE (14%). CUR exhibited highest percentage antioxidant activity (87.1%) followed by NSE (77.6%) and GSE (61.4%) using phosphomolybdenum method. In Contrary, increased order of antioxidant activity using FTC-linoleic system was GSE > CUR > NSE. All the mentioned experiments were also conducted using vitamin E as a standard antioxidant. Strong linear regression between the total phenolic contents and above parameters in studied samples were noticed as indicated by high r2 at P Conclusions Our results indicated that, reducing power and antioxidative potentials of GSE, NSE and CUR may be attributed to high total phenolic contents. GSE, NSE and CUR may be valuable as food preservative and nutritional health supplements.

Total phenolic contents and free radical scavenging activity of certain Egyptian Ficus species leaf samples

The antioxidative phytochemicals in grains, vegetables, fruits and medicinal plants have received increasing attention for their potential role in prevention of human diseases. The methanol extracts of the leaves of eleven Ficus species growing in Egypt were subjected to free radical scavenging activity using 1,1-diphenyl picrylhydrazyl (DPPH ) method. Six methanol extracts of six species showed high activity in order: Ficus lyrata Warb. > Ficus afzelli G. > Ficus nitida L. > Ficus virens Ait. > Ficus sycomorus L. > Ficus decora Hort. with SC 50 38.37, 60.22, 61.67, 74.00, 79.50 and 81.62 μg/ml, respectively. The free radical scavenging activity of different fractions obtained from successive fractionation of the six methanol extracts with organic solvents of different polarities; petroleum ether, CHCl 3, EtOAc and n-BuOH; showed that, the EtOAc and n-BuOH fractions have the high activity with SC 50 < 50 μg/ml whereas petroleum ether and CHCl 3 fractions have weak activity at SC 50 > 200 and 100 μg/ml, respectively. The EtOAc and n-BuOH fractions of F. lyrata showed the strongest free radical scavenging activity on DPPH with SC 50 = 8.27 and 12.14 μg/ml, respectively and also the highest antioxidant capacity monitored by phosphomolybdenum method (928.48 and 728.53 mg equivalent to ascorbic acid/g extract). Preliminary phytochemical investigation of the six active EtOAc and n-BuOH fractions guided by review of literatures of this genus showed that phenolic compounds constitute the major components of it. The total phenolic, tannin, flavonoid and flavonol contents of the six active EtOAc and n-BuOH fractions were measured using the well established methods. Linear correlation between the total antioxidant capacity of the six active EtOAc and n-BuOH fractions and the total phenolic and flavonoid contents were observed. More in vivo and in vitro studies along with detailed photochemical investigation are needed in the hope to can use these species (crude extract, fractions, sub-fractions or pure compounds) in the prevention and therapies of diseases in which oxidants or free radicals are involved.

Studies on Indian Green Leafy Vegetables for Their Antioxidant Activity

To identify the potential of green leafy vegetables (GLV) as antioxidants, methanolic extracts of Amaranthus sp., Centella asiatica, Murraya koenigii and Trigonella foenum graecum were studied for their antioxidant activity in different systems at multiple concentrations. Total antioxidant activity assessed by phosphomolybdenum method, free radical scavenging activity by 1,1-diphenly-2-picryl hydrazyl (DPPH), reducing power and ferrous ion chelating activity were determined. The GLV were analyzed for ascorbic acid, total and beta-carotene and total polyphenol contents. The ascorbic acid, total carotene, beta-carotene and total phenolic content (tannic acid equivalents) of the GLV ranged between 15.18-101.36, 34.78-64.51, 4.23-8.84 and 150.0-387.50 mg/100 g GLV, respectively. The extracts were found to have significantly different levels of antioxidant activities in the systems tested. The total antioxidant activity was highest in Murraya koenigii (2,691.78 micromol of ascorbic acid/g sample) and least in Centella asiatica (623.78 micromol of ascorbic acid/g sample). The extract concentration causing 50% inhibition of DPPH (IC50) was determined (M. koenigii<C.asiatica<Amaranthus sp.<T. graecum). The maximum DPPH scavenging activity and reducing power was exhibited by Murraya koenigii. Multiple regression analysis showed that the relationship of total antioxidant activity, free radical scavenging activity, and reducing power with polyphenol and total and beta-carotene was highly significant.

Antioxidant activities of Erythrina stricta Roxb.using various in vitro and ex vivo models

Erythrina stricta, a deciduous tree widely used traditionally in indigenous system of medicine for various ailments such as rheumatism, fever, leprosy, epilepsy etc. The leaves of Erythrina stricta was extracted with ethanol (70%) and used for the evaluation of various in vitro antioxidant assays which includes H - donor activity, nitric oxide scavenging, superoxide anion scavenging, reducing ability, hydroxyl radical, hydrogen peroxide scavenging, total phenolic content, total flavonoid content, total antioxidant activity by thiocyanate and phosphomolybdenum method, metal chelating, <TEX>$\beta$</TEX>-carotene bleaching, total peroxy radical assays. The pro-oxidant activity was measured using bleomycin-dependent DNA damage. Ex vivo models like lipid peroxidation and erythrocyte haemolysis were also used to study the antioxidant property of the extract. The various antioxidant activities were compared with suitable standard antioxidants such as ascorbic acid, butylated hydroxyl toluene, <TEX>$\alpha$</TEX>-tocopherol, curcumin, quercetin and Trolox. The generation of free radicals viz. <TEX>$O_2^{{\cdot}-}$</TEX>, <TEX>$OH^{\cdot}$</TEX>, <TEX>$H_2O_2$</TEX>, <TEX>$NO^{\cdot}$</TEX> and peroxyl radicals were effectively scavenged by the ethanolic extract of Erythrina stricta. In all the methods, the extract offered strong antioxidant activity in a concentration dependent manner. The total phenolic content, flavonoid content and total antioxidant activity in Erythrina stricta were determined as microgram (g) pyrocatechol, quercetin and <TEX>$\alpha$</TEX>-tocopherol equivalent/mg respectively. The extract did not exhibit any prooxidant activity when compared with ascorbic acid. The results obtained in the present study clearly indicates that Erythrina stricta scavenges free radicals and reduces lipid peroxidation, ameliorating the damage imposed by oxidative stress in different disease conditions and serve as a potential source of natural antioxidant.

Antioxidant activities of extracts and fractions from Lysimachia foenum-graecum Hance

The antioxidant activities of water extract, methanol extract, ethyl acetate, and n-BuOH fractions of methanol extract from Lysimachia foenum-graecum Hance were investigated in this study. Various methods, such as the total antioxidant capacity measured by phosphomolybdenum method, scavenging activities towards 1,1-diphenyl-2-picryhydrazyl (DPPH) radical, superoxide anion radical, and hydroxyl radical, were established in in vitro systems. The amounts of total phenolics and total flavonoids in the extracts and fractions were also determined by spectrophotometric methods. The results showed that all the extracts and fractions exhibited antioxidant and radical-scavenging activities at different magnitudes of potency. The decreasing order of antioxidant and radical-scavenging activities among the extracts assayed through all the four methods were found to be ethyl acetate fraction>n-BuOH fraction>methanol extract>water extract. This similar order of the amounts of total phenolics and total flavonoids shows that the extent of antioxidant and radical-scavenging activities is in accordance with the amounts of phenolics and flavonoids present in extracts and fractions. The extracts of L. foenum-graecum Hance might be valuable antioxidant natural sources and seemed to be applicable in both healthy medicine and food industry.

Non-Phenolic Antioxidant Compounds from Buddleja asiatica

The methanol extract of the leaves of Buddleja asiatica Lour. (Loganiaceae) showed antioxidant activity toward the well known in vitro antioxidant tests such as total antioxidant capacity by the phosphomolybdenum method, free radical scavenging activity by the 1,1-diphenyl-2-picrylhydrazyl scavenging assay (DPPH assay) and hydrogen peroxide scavenging methods. Due to the high scavenging activity of the n-butanol successive fraction toward DPPH and H2O2 (SC50 = 11.99 and 18.54 microg/ml, respectively), this extract was subjected to chromatographic separation and isolation. Four non-phenolic compounds were isolated and identified on the basis of spectroscopic and chemical analyses: 1-O-beta-D-glucopyranosyl-2-methoxy-3-(2-hydroxy-triaconta-3,12-dienoate)-glycerol (1), 3-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->3)]-[beta-D-glucopyranosyl-(1-->2)]-beta-D-fucopyranosyl-olean-11,13(18)-diene-3 beta,23,28-triol (2), 3-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->3)]-beta-D-fucopyranosyl-olean-11,13(18)-diene-3,23,28-triol (3), and 3-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->3)]-[beta-D-xylopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl-acid-olean-11,13(18)-diene-3 beta,23,28-triol (4). The four compounds were evaluated as antioxidant agents using the three antioxidant bioassay tests.

Antioxidant activity of polyphenols from Lycopus lucidus Turcz

The aim of this paper was to evaluate the antioxidant properties of the different extracts from Lycopus lucidus (crude methanolic extract, dichloromethane, diethyl ether and ethyl acetate sub-fractions) and to correlate their antioxidant potential to the composition of polyphenols. The ability of deactivating free radicals was measured using DPPH and NO scavenging assays. The reducing power towards transition metals was tested by the phosphomolybdenum method. Qualitative and quantitative analyses of major phenolic acids were also performed. The main antioxidant compound from the methanol extract was confirmed to be rosmarinic acid. Other identified phenolic acids that are likely to contribute to the antioxidant potential are: ferulic, caffeic, chlorogenic, vanillic, p-hydroxybenzoic acid, p-coumaric acid and protocatechuic acid. The most active ethyl acetate extract contained the highest level of rosmarinic acid, but the luteolin glycosides are also the major determinants of the antioxidant activity as has been revealed by analysis of the two most active fractions from column chromatography. These two classes of antioxidants are likely to act synergistically in the ethyl acetate fraction and the crude extract of the plant.

In vitro free radical scavenging activity of Ixora coccinea L

Antioxidant activity of the methanol extract of Ixora coccinea L. was determined by DPPH free radical scavenging assay, reducing power and total antioxidant capacity using phosphomolybdenum method. Preliminary phytochemical screening revealed that the extract of the flower of I. coccinea possesses flavonoids, steroids and tannin materials. The extract showed significant activities in all antioxidant assays compared to the standard antioxidant in a dose-dependent manner and remarkable activities to scavenge reactive oxygen species (ROS) may be attributed to the high amount of hydrophilic phenolics. In DPPH radical scavenging assay the IC50 value of the extract was found to be 100.5 μg/mL while ascorbic acid had the IC50 value 58.9 μg/mL. Moreover, I. coccinea extract showed strong reducing power and total antioxidant capacity.