Radical Cation Scavenging Assay Research Articles

Comparative Antioxidant and Antimicrobial Activities of Several Conifer Needles and Bark Extracts.

Nowadays, an increased concern regarding using natural products for their health benefits can be observed. The aim of this study was to assess and compare several phenolic compounds found in 15- to 60-year-old Douglas fir, silver fir, larch, pine, and spruce needle and bark extracts and to evaluate their antioxidant and antimicrobial activities. Spectrophotometric assays were used to determine the total polyphenol content and the antioxidant activity that was assessed by using the DPPH• radical scavenging assay (RSA), the ferric reducing antioxidant power assay (FRAP), and the ABTS•+ radical cation scavenging assay (ABTS). The phytochemical content was determined by using high-performance liquid chromatography, and the antimicrobial activity was determined by assessing the minimal inhibition concentration (MIC). The results of the study show a total polyphenol content of 62.45-109.80 mg GAE/g d.w. and an antioxidant activity of 91.18-99.32% for RSA, 29.16-35.74 µmol TE/g d.w. for FRAP, and 38.23-53.57 µmol TE/g d.w. for ABTS. The greatest quantity of phenolic compound for most of the extracts was for (+)-catechin, and it had values between 165.79 and 5343.27 µg/g d.w. for these samples. The antimicrobial inhibition for all the extracts was the strongest for Staphylococcus aureus (MIC 62.5-125 µg/mL). The extracts analyzed could be used for their bioactive potential after further investigations.

Green synthesis of silver nanoparticles using Onobrychis sativa L.: Characterization, catalytic degradation of methylene blue, antioxidant activity, and quantitative analysis of bioactive compounds

The synthesis of silver nanoparticles was achieved using Onobrychis sativa extract of leaves and flowers mixture and their structures were characterized by spectroscopic study. The appearance of maximum absorption at 442 nm in UV-Vis spectroscopy verified the silver nanoparticles (AgNPs@Os) structure. The functional groups of natural compounds in O. sativa acting as reducing and stabilizing agents were presented by FTIR. The typical signal appeared at 3211 cm−1 belonging to the OH moiety. The diffraction peaks by X-ray XRD analysis (2θ) at 38.16°, 44.31°, 64.49°,77.38°, and 81.52 degrees may relate to 111, 200, 220, 311, and 222 facets presenting the face-centered cubic unit structure (fcc). The stability of AgNPs@Os was determined by zeta potential as − 34.2 mV. Moreover, the histogram of DLS revealed the average size of nanoparticles in suspension. TEM analysis displayed that AgNPs@Os were quasi-spherical and the average magnitude was 14.7 nm. The intense peak at 2.5–3.5 keV in EDX spectrum approved the structure of the nanoparticles. The catalytic degradation of methylene blue by sodium borohydride in the presence of AgNPs@Os as a catalyst was investigated and degradation was found to be 68 % in 30 min. Antioxidant activity of extract and AgNPs@Os was conducted using the DPPH• free radical scavenging, ABTS•+ radical cation scavenging, FRAP, and superoxide anion radical scavenging assays. AgNPs@Os exhibited excellent activity. Quantitative analysis of bioactive compounds in water extract was carried out by HPLC after nanoparticles synthesis and gallic acid was found as a major compound.

High-performance liquid chromatography micro-fraction bioactive evaluation combined with countercurrent chromatographic separation of antioxidants from Citrus peel and their tyrosinase inhibition activities.

In the present study, high-performance liquid chromatography micro-fraction bioactive evaluation and high speed countercurrent chromatography were performed on screening, identification and isolation of antioxidants from Citrus peel. Three compounds were screened as antioxidants and tyrosinase inhibitors using 2,2'-azino-bis (3-ethyl-benzothiazoline-6-sulfonic acid) radical cation scavenging assay and tyrosinase activity test, then they were identified as eriocitrin, narirutin and hesperidin. Moreover, the solvent system ethyl acetate-n-butanol-water (6:4:10, v/v/v) was used for separation of ethyl acetate extract of Citrus peel by high speed countercurrent chromatography. In total, 0.45mg of eriocitrin with 87.10% purity, 2.04mg of narirutin with 95.19% purity and 1.35mg of hesperidin with 95.19% purity were obtained from 20mg of ethyl acetate extract of Citrus peel in a single run and then each component was subjected to 2,2'-azino-bis (3-ethyl-benzothiazoline-6-sulfonic acid) radical cation scavenging assay and tyrosinase inhibition assay. Eriocitrin showed great antioxidant activity (the half-maximum concentration: 3.65µM) and tyrosinase inhibition activity (the half-maximum concentration: 115.67µM), while narirutin and hesperidin exhibited moderate activity. Tyrosinase inhibition activity for eriocitrin in vitro was reported for the first time. Furthermore, molecular docking between eriocitrin and mushroom tyrosinase was also studied.

PHYTOCHEMICAL INVESTIGATION AND EVALUATION OF ANTIOXIDANT, AND ANTI-INFLAMMATORY ACTIVITY OF AERIAL PARTS OF Lindernia antipoda

Plant species always remain a backbone for the discovery of active biomolecules required for public health. The existing scrutiny is outlined to dissect the chemical nature and explore the antioxidant and anti-inflammatory strength of methanol extract of aerial parts of Lindernia antipoda by in vitro methods. The basic phytochemical evaluation of the extract reflected the existence of essential nitrogenous and phenolic bio-compounds. UV-visible and FTIR (Fourier Transform-Infrared Spectroscopy) spectral analysis supported the chemical nature of reflected compounds. The antioxidant capability was noticed through nitric oxide scavenging assay and ABTS [2,2’-azinobis-(3- ethylbenzothiazoline-6-sulfonic acid)] radical cation scavenging assay while anti-inflammatory competence was examined through the stabilization approach of human erythrocytes membrane against heat-induced membrane lysis. The methanol extract showed nitric oxide scavenging and ABTS radical cation scavenging by IC50 values of 398.38 μg/mL and 513.30 μg/mL respectively while anti-inflammatory activity was observed with the IC50 value of 573.01 μg/mL. The outcomes of each activity of methanol extract are presumably linked to the essential bioactive chemical substances in the extract

Antioxidant capacity and metabolic characterization of aqueous and ethanolic extraction of Saraca indica

Saraca indica (Ashoka) is an important medicinal plant and the compounds present in this plant are very helpful in preventing various diseases. Further, it is an important drug used in many Ayurvedic formulations. Asoka is used in Ayurveda to treat a variety of conditions, including excessive uterine bleeding, gynaecological issues, internal piles, diabetes, dyspepsia, indigestion, burning sensation, blood disorders, fractures, tumours, bites, ulcerations, etc. Therefore, keeping in view of above beneficial effects, the aim of the present study was to investigate phytochemical screening, antioxidant capacity and metabolic characterization of aqueous and ethanolic extraction of Saraca indica. Phytochemical evaluation was performed using standard protocol. The in vitro antioxidant activity, total phenolic content and total flavonoid content was determined. UV visible spectroscopy was used to recognize quantitative determination. The active metabolites of the plant Saraca indica have been studied using Fourier transform-infrared spectroscopy and gas chromatography-mass spectrometry. IC50 values of DPPH radical scavenging assay for aqueous and ethanolic extracts were 380µg/ml and 350µg/ml, respectively. IC50 values of ABTS+ radical cation scavenging assay for aqueous and ethanolic extracts were 200µg/ml and 350µg/ml, respectively. Major functional groups and active metabolic compounds in the S. indica were identified by FT-IR and GCMS, respectively. Saraca indica is an excellent source of natural antioxidants and the antioxidant activity observed may be due to phenolic and flavonoid content in the aqueous and ethanolic extract.

Determination of antioxidant capacity, citric acid, phenolic compounds, physicochemical and sensory properties of Pepino marmalade yogurts enriched with erythritol and amaranth flour at different concentrations.

This work aimed to evaluate the feasibility of fortifying Pepino marmalade containing erythritol and amaranth flour (1, 2, and 3%) as the source of antioxidants, dietary fiber, and polyphenols in yogurt for increasing nutritional value and improving storability. Both Pepino marmalade and amaranth flour increased the phenolic content, citric acid value, viscosity, and WHC of the yogurt samples. The diphenyl-1 picrylhydrazyl scavenging activity (DPPH), radical cation (ABTS*+) scavenging assay, oxygen radical absorption capacity (ORAC), and ferric-reducing antioxidant capacity (FRAP) were found to be in the range of 4.5-46.6%, 166.2-1022µg AAE/g, 2.61-4.49 µmol Trolox/g, and 4.9-23.88 µmol Fe2+/g respectively. As the concentration of marmalade and amaranth flour increased, the samples showed higher b* and lower a* and L* values. In addition, the panelists stated that they enjoyed the yogurt samples with Pepino marmalade and amaranth flour.

Co-Encapsulation of Tannic Acid and Resveratrol in Zein/Pectin Nanoparticles: Stability, Antioxidant Activity, and Bioaccessibility.

Hydrophilic tannic acid and hydrophobic resveratrol were successfully co-encapsulated in zein nanoparticles prepared using antisolvent precipitation and then coated with pectin by electrostatic deposition. The encapsulation efficiencies of the tannic acid and resveratrol were 51.5 ± 1.9% and 77.2 ± 3.2%, respectively. The co-encapsulated nanoparticles were stable against aggregation at the investigated pH range of 2.0 to 8.0 when heated at 80 °C for 2 h and when the NaCl concentration was below 50 mM. The co-encapsulated tannic acid and resveratrol exhibited stronger in vitro antioxidant activity than ascorbic acid, as determined by 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH·) and 2,2'-azinobis (3-ethylberizothiazoline-6-sulfonic acid) radical cation (ABTS+·) scavenging assays. The polyphenols-loaded nanoparticles significantly decreased the malondialdehyde (MDA) concentration and increased the superoxide dismutase (SOD) and catalase (CAT) activities in peroxide-treated human hepatoma cells (HepG2). An in vitro digestion model was used to study the gastrointestinal fate of the nanoparticles. In the stomach, encapsulation inhibited tannic acid release, but promoted resveratrol release. However, in the small intestine, it led to a relatively high bioaccessibility of 76% and 100% for resveratrol and tannic acid, respectively. These results suggest that pectin-coated zein nanoparticles have the potential for the co-encapsulation of both polar and nonpolar nutraceuticals or drugs.

Study on biochemical analysis, antioxidant assay and GCMS analysis of Saccharina japonica

Marine algae are one of the largest sources for biogenic compounds. They produce a wide variety of chemically active metabolites. They are found to possess significant antioxidant, and phytochemical activities. Macroalgae provide a great variety of metabolites and natural bioactive compounds with antimicrobial activity, such as polysaccharides, polyunsaturated fatty acids, phlorotannins other phenolic compounds and carotenoids. In the present study the phytochemical, amylase activity, GCMS and Antioxidant assays such as ABTS assay and DPPH assays were carried out for Saccharina japonica using two different solvents, petroleum ether and ethyl acetate. For antioxidant activity, DPPH radical assay and ABTS radical cation scavenging assay were carried out.

Proteome Analysis and In Vitro Antiviral, Anticancer and Antioxidant Capacities of the Aqueous Extracts of Lentinula edodes and Pleurotus ostreatus Edible Mushrooms.

In this study, we examined aqueous extracts of the edible mushrooms Pleurotus ostreatus (oyster mushroom) and Lentinula edodes (shiitake mushroom). Proteome analysis was conducted using LC-Triple TOF-MS and showed the expression of 753 proteins by Pleurotus ostreatus, and 432 proteins by Lentinula edodes. Bioactive peptides: Rab GDP dissociation inhibitor, superoxide dismutase, thioredoxin reductase, serine proteinase and lectin, were identified in both mushrooms. The extracts also included promising bioactive compounds including phenolics, flavonoids, vitamins and amino acids. The extracts showed promising antiviral activities, with a selectivity index (SI) of 4.5 for Pleurotus ostreatus against adenovirus (Ad7), and a slight activity for Lentinula edodes against herpes simplex-II (HSV-2). The extracts were not cytotoxic to normal human peripheral blood mononuclear cells (PBMCs). On the contrary, they showed moderate cytotoxicity against various cancer cell lines. Additionally, antioxidant activity was assessed using DPPH radical scavenging, ABTS radical cation scavenging and ORAC assays. The two extracts showed potential antioxidant activities, with the maximum activity seen for Pleurotus ostreatus (IC50 µg/mL) = 39.46 ± 1.27 for DPPH; 11.22 ± 1.81 for ABTS; and 21.40 ± 2.20 for ORAC assays. This study encourages the use of these mushrooms in medicine in the light of their low cytotoxicity on normal PBMCs vis à vis their antiviral, antitumor and antioxidant capabilities.

Functionalization of Betulinic Acid with Polyphenolic Fragments for the Development of New Amphiphilic Antioxidants.

The present work aimed at the valorization of biomass derived compounds by their transformation into new added-value compounds with enhanced antioxidant properties. In this context, betulinic acid (BA) was decorated with polyphenolic fragments, and polyhydroxylated (E)-2-benzylidene-19,28-epoxyoleanane-3,28-diones 4a–d were obtained. For that, the synthetic strategy relied on base-promoted aldol condensation reactions of methyl betulonate, which was previously prepared from natural BA, with appropriate benzaldehydes, followed by cleavage of the methyl protecting groups with BBr3. It is noteworthy that the HBr release during the work-up of the cleavage reactions led to the rearrangement of the lupane-type skeleton of the expected betulonic acid derivatives into oleanane-type compounds 4a–d. The synthesized compounds 4a–d were designed to have specific substitution patterns at C-2 of the triterpene scaffold, allowing the establishment of a structure-activity relationship. The radical scavenging ability of 4a–d was evaluated using the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid radical cation (ABTS•+) scavenging assays. In particular, derivative 4c, bearing a catechol unit, revealed to be the most efficient scavenger against both free radicals DPPH• and ABTS•+. Subsequently, we designed two analogues of the hit derivative 4c in order to achieve more potent antioxidant agents: (i) the first analogue carries an additional unsaturation in its lateral chain at C-2 (analogue 5) and (ii) in the second analogue, E-ring was kept in its open form (analogue 6). It was observed that the presence of an extended π-conjugated system at C-2 contributed to an increased scavenging effect, since analogue 5 was more active than 6, α-tocopherol, and 4c in the ABTS•+ assay.

Synthesis and antioxidant activity of conjugates of hydroxytyrosol and coumarin

Antioxidants have been the subject of intense research interest due to their numerous health benefits. In this work, a series of new conjugates of hydroxytyrosol and coumarin were synthesized and evaluated for their free radical scavenging, toxicity and antioxidant mechanism in vitro. The all target compounds 14a–t exhibited better radical scavenging activity than BHT, hydroxytyrosol, and coumarin in both DPPH radical and ABTS+ radical cation scavenging assays. The structure-activity relationships study indicated that the number and position of hydroxyl groups on the coumarin ring were vital to a good antioxidant capacity. Furthermore, the most promising compound 14q showed less toxicity in hemolysis assay and weaker antiproliferative effects than BHT against normal WI-38 and GES cells, and enhanced viability of H2O2-induced HepG2 cells. Additionally, 14q decreased the apoptotic percentage of HepG2 cells, reduced the ROS produce and LDH release, and improved GSH and SOD levels in H2O2-treated HepG2 cells. Lastly, 14q exhibited more stability than hydroxytyrosol in methanol solution. These results revealed that conjugations of hydroxytyrosol and coumarin show better antioxidant capacity, and are the efficacious approach to finding novel potential antioxidant.

Determination of Several Bitlis Honeys based on their Botanic and Biochemical Profiles

Objective: In this paper, we aimed to evaluate the pollen composition and antioxidant activity of 4 randomly selected honey samples from the Bitlis region in 2017. Material and Method: The melisopalynological analysis was used standard protocol without acetolysis. The antioxidant activity of samples were evaluated using several in vitro methods, 1,1-diphenyl-2-picrylhydrazyl free radical scavenging activity (DPPH), hydrogen peroxide scavenging activity (HPSA), Ferrous ions chelating activities (FICA), 2,2’-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid radical cation scavenging assays (ABTS) and the ferric reducing antioxidant power assays (FRAP). Result and Discussion: All the samples were determined as multifloral honey. Outcomes obtained declared that the antioxidant activity changed remarkably from honey to honey. ABTS and FICA of samples differ slightly each other’s. DPPH, HPSA, and FRAP were ranged from between 54.45 – 387.60 µg/mL, 212.11 – 246.64 µg/mL and 47.20 – 78.23 %, respectively. In addition, total phenol and total flavonoid contents were determined. Comparatively, Sample 3 showed highest levels of phenolic and flavonoid content (626.48 mg GAE/100 g and 4.4 mg CAE/100 g, respectively) in ethanol extract. Almost all the samples are well source for antioxidants.

Antioxidant Potential and Stabilization Studies of Sunflower Oil Using Sorbaria tomentosa Extract and its Cu(II)/Zn(II) Chelates

Sorbaria tomentosa,, commonly known as “Berre” is native to Himalaya and Hindukush range in Pakistan. Qualitative phytochemical screening as well as quantitative antioxidant potential of its ethanolic extract was evaluated. Antioxidant potential of the extract was determined using standard methods like DPPH, FRAP, total phenolics, total flavonoids, ABTS radical cation scavenging assay and β-carotene linoleic acid emulsion system. Cu(II) and Zn(II) chelates of ,,Sorbaria tomentosa,, were also prepared and their antioxidant potential was compared with the extract as well as with synthetic antioxidants (BHT and BHA). It was observed that ,,Sorbaria tomentosa,, is a good source of natural antioxidant that worked efficiently compared to respective chelates. Keeping in view less efficiency of chelated extracts, stabilization studies of sunflower oil were conducted with ethanolic extract (250, 500, 1000 ppm) of ,,Sorbaria tomentosa,,. Various parameters like PV, FFA and IV were estimated to evaluate stabilization of oil. ,,Sorbaria tomentosa,, extract (1000 ppm) showed almost same role during stabilization like BHA at ambient condition during a storage period of 45 days. Keywords: Sorbaria tomentosa, phytochemicals, antioxidant potential, chelation, stabilization

Analysis of chemical components and biological activities of essential oils from black and white pepper (Piper nigrum L.) in five provinces of southern China

The chemical composition and antioxidant and antifungal activities of hydro-distilled essential oils (EOs) in black and white Piper nigrum L were evaluated in the present study. Hydro-distilled EOs obtained from black and white P. nigrum L from five areas of China was analyzed by gas chromatography-mass spectrometry (GC-MS). Nineteen compounds were identified, accounting for 98.20–99.35% of the oils. Chemical variation in the oils was estimated using systematic cluster analysis and principal component analysis. Moreover, antioxidant activity was determined by DPPH and ABTS radical cation scavenging assay, ferric reducing power assay, and ferric ion chelating activity assay, scavenging superoxide anion free radical activity assay and antifungal activity were assessed by micro-well dilution assay. Our results suggest that the region of origin greatly influences the pepper's chemical composition and bioactivities, which might support the development and utilization of this promising bio-resource in food industries.

Antioxidant capacity of germinated quinoa-based yoghurt and concomitant effect of sprouting on its functional properties

In this study, functional yoghurt was produced from germinated and ungerminated quinoa seeds of two different cultivars (Mengli 1 and Mengli 2) obtained from Inner Mongolia Province, China. The effect of germination on the physicochemical, antioxidant compounds, and antioxidant capacity was determined. In the results obtained, germination influenced the nutritional qualities of quinoa yoghurt to a large extent. Total phenolic content (TPC) and Total flavonoid content (TFC) were the highest in germinated quinoa yoghurt of both cultivars. Germinated quinoa yoghurt also recorded high antioxidant capacities with 2,21, diphenyl-1 picrylhydrazyl scavenging activity (DPPH), ferric reducing antioxidant capacity (FRAP), radical cation (ABTS*+) scavenging assay and oxygen radical absorption capacity (ORAC) assays. Thus, it was concluded that yoghurt produced from germinated quinoa could serve as functional yoghurt beneficial for human health.

Matrix effect evaluation and validation of the 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical cation scavenging assay, as well as its application using a tejate, an ancient beverage in Mexico

Nowadays, consumers, food industries, and researchers have a great interest in evaluating the total antioxidant value of foodstuffs and plasma samples. The 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation scavenging assay is one of the most common antioxidant evaluations. However, this assay shows a great variability in its methodology, e.g., the use of a phosphate buffered saline (PBS) matrix. Moreover, all prior assays did not describe a complete validation procedure. This study demonstrated that the matrix of calibration standards had a significant effect on the accuracy of antioxidant measurements, under the ABTS radical cation scavenging assay. A PBS matrix should only be used in this assay during plasma analysis due to a negative matrix effect on calibration curves. Meanwhile, a PBS-free matrix should be used during analyses of water-based beverages. Our analytical validation showed that the current assay had an inverse lineal relationship, acceptable range, sensitivity, precision, accuracy, short and long-term stability, selectivity, identity, and short time of analysis. Additionally, this study showed that a traditional Southern Mexico beverage (tejate) had antioxidant properties (inhibition of the ABTS radical cation and ability to reduce the ferric ion) due to the presence of polyphenol compounds. The biological relevance was supported by a high plasma antioxidant activity in rats after a 7-day period of tejate consumption.

Essential oils of Moldavian Thymus species: Chemical composition, antioxidant, anti‐Aspergillus and antigenotoxic activities

AbstractThymus species are important aromatic, medicinal and culinary plants with a significant economic value. This study evaluated for the first time the chemical composition and in vitro bioactivities of the essential oils (EOs) from five Moldavian Thymus species (T. vulgaris, T. × citriodorus, T. calcareus) and cultivars (T. vulgaris ‘Faustini’, T. citriodorus ‘Aureus’). The main compounds in Thymus EOs were: thymol in T. vulgaris and T. calcareus EOs (55.44% and 55.45%, respectively), lavandulol in T. × citriodorus EO (54.27%), and geraniol in T. citriodorus ‘Aureus’ and T. vulgaris ‘Faustini’ EOs (60.31% and 31.45%, respectively). T. vulgaris and T. calcareus EOs showed the most potent antioxidant activities (EC50=0.003 mg/mL in ABTS radical cation scavenging assay) and exhibited significant inhibitory effects against aflatoxin‐producing Aspergillus flavus fungus (MIC=0.25 μL/mL). At doses that provided micromolar concentrations of thymol, T. vulgaris and T. calcareus EOs acted genoprotective at preventive and interventional levels against H2O2‐induced genomic damage in V79 cells, the former being more active (6.21% and 5.52% vs. 25.13% and 7.26% tail DNA in pre‐ and post‐treatment protocols, respectively). The genoprotective effects may be ascribed to antioxidant potential and, possibly, to stimulation of DNA repair processes. The Moldavian Thymus species are valuable resources of bioactive EOs for pharmaceutical and food industries (T. vulgaris, T.calcareus) but also for flavor industry and perfumery (T. × citriodorus, T. citriodorus ‘Aureus’, T. vulgaris ‘Faustini’).

Phytochemical Screening and in vitro Antioxidant Properties of Methanol and Aqueous Leaf Extracts of Geophila obvallata

Aim: This study investigated the phytochemical constituents and in vitro antioxidant properties of methanol and aqueous leaf extracts of Geophila obvallata using standard methods.
 Materials and Methods: The in vitro antioxidant assays carried out were 1, 1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging ability, Nitric oxide (NO•) radical scavenging activity assay, 2, 2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS•+) radical cation scavenging assay, ferric reducing properties and hydroxyl radical scavenging assays.
 Results: Phytochemical analysis revealed the presence of alkaloids, flavonoids, phenolic compounds, steroids, saponins, terpernoids and cardiac glycosides in both extracts. Relative to the aqueous extract, the methanol extract contained a higher amount of the secondary metabolites. However, both extracts exhibited appreciable and dose-dependent capacities for quenching DPPH, ABTS•+ and NO• free radicals, and potent ferric reducing ability to levels comparable to those of ascorbic acid. The crude methanol extract showed significantly increased (P<0.05) antioxidant activity than the aqueous extract.
 Conclusion: It was concluded that the extract possesses strong antioxidant properties due to its content of phytochemicals, and provides scientific basis for its ethno medicinal applications.

Synthesis and in vitro Antioxidant Activity Study of Some Novel Substituted Piperazinyl Flavone Compounds.

A new series of 13 piperazinyl flavone derivatives has been synthesized and examined for their in vitro antiradical and antioxidant activities in response to the pharmacy industry's increasing demand for new non-toxic anti-inflammatory and anticancer drugs. Their antioxidant activity was evaluated by the reactive oxygen species (ROS) scavenging assays, 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH•) and 2,2'-azino-bis(3- ethylbenzothiazoline-6-sulphonic acid) radical cation (ABTS+•) scavenging assays, and the ferric reducing antioxidant potency (TAC) method, and was compared to known positive controls, herbal infusions, and penicillins. Chemiluminescence, spectrophotometry, electron spin resonance (ESR) and 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) as the spin trap were the measurement techniques. It was seen that synthesized compounds have a wide spectrum of antioxidant property. Some of the test compounds proved to be extremely efficient scavengers of H2O2 exhibiting, in some cases, EC50 of about 2 µM. The values of antioxidant status (TAS) were in the range of 49 ± 3.9 to 1283 ± 51.3 µM TE/g (TE = Trolox equivalent) and were lower than that of butylated hydroxytoluene (BHT) (1304 ± 43.2 µM TE/g) and green tea (1356 ± 40.0 µM TE/g), but for several synthesized compounds, they were higher than chamomille infusion and penicillins. Ferric reducing antioxidant powers (TAC) for the piperazinyl flavone derivatives were in the range 7 ± 0.5 to 104 ± 0.6 µM TE/g and were weaker than that of BHT (217 ± 5.3 µM TR/g ). Carboxylic or hydroxamic acid substituted piperazinyl flavones are potentially active as antioxidants, thus may be suggested as pharmacologically interesting ones.

Antioxidative and Antihypertensive Activities of Selected Malaysian ulam (salad), Vegetables and Herbs

This study was conducted to investigate antioxidative and antihypertensive activities of selected Malaysian ulam (salad), vegetables and herbs. The aqueous extract of selected ulam (salad), vegetables and herbs were analysed for total phenolic content (TPC), antioxidant activities (2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, 2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) radical cation scavenging assay and ferric reducing antioxidant power assay (FRAP) and antihypertension activity (angiotensin converting enzyme (ACE) inhibitory activity assay). TPC analysis showed that Polygonum minus contains significantly (p<0.05) highest phenolic compound at 48.23 ± 0.17 mg GAE/g as compared to other plants. DPPH analysis showed that P. minus had significantly (p<0.05) highest percentage of radical scavenging activity at 79.09 ± 0.10% as compared to other plants. ABTS analysis showed that Sauropus androgynus had significantly (p<0.05) highest percentage of radical cation scavenging activity at 95.10 ± 0.26% as compared to other plants. FRAP analysis showed that P. minus had significantly (p<0.05) highest ferric reducing power at 63.61 ± 0.73 mmol Fe2+/g as compared to other samples. Murraya koenigii had the highest percentage of ACE inhibitory activity (91.20 ± 4.15%). Correlation analysis showed positive and significant (p<0.01) correlation between TPC and FRAP (r = 0.956), TPC and ABTS (r = 0.635), TPC and DPPH (r = 0.630) and TPC and ACE inhibitors (r = 0.645). This shows that Malaysian tropical plants especially P. minus are potential source of natural antioxidant and antihypertensive agents.