Radical Inhibition Assay Research Articles

Bioactivity and Dereplication of Phenolic Compounds in Medicinal Plants

Three medicinal plants with recognized anti-inflammatory potential, identified as “erva de São João“ (Ageratum conyzoides), “Tanchagem“ (Plantago major) and “ Bardana“ (Arctium lappa L.) were obtained from a medicinal herbs company located in Teófilo Otoni city (Minas Gerais State, Brazil). The dry plant material obtained in packages was submitted to the chemical procedures to prepare the crude extracts by maceration according to the Brazilian pharmacopoeia legislation. After extraction, the samples were subjected to 1H NMR, TLC and Capillary Electrophoresis analysis by co-injection of authentic patterns of phenolic acids and flavonoids to identify the major compounds and classes of secondary metabolites present in each material and then their chemical and biological potential was assessed by DPPH free radical inhibition assay and antimicrobial against E. coli. The results obtained allow us to conclude that the phytopreparation was effective in the extraction of compounds with antioxidant potential and the three species presented a high concentration of flavonoids and other phenolics that is compatible with the chemosystematic data. The screening obtained by 1H NMR spectroscopy, TLC and Capillary Electrophoresis with ultraviolet detection analysis provided us a qualitative profile of the phytochemicals present in each material. None of the extracts were active against Escherichia coli by antibacterial disk diffusion assay at concentration of 1 mg/ml.

Environmental friendly synthesis of silver nanomaterials from the promising Streptomyces parvus strain Al-Dhabi-91 recovered from the Saudi Arabian marine regions for antimicrobial and antioxidant properties

The therapeutic molecules recovered from the marine biological origin are widely used for the treatment of diverse levels of infections caused by microbial pathogens. In addition, the eco-friendly preparations of nanomaterials together with the secondary metabolites' producing active microbial strains effectively suppress the spreading of the pathogenic bacteria. Considering their importance, the present study evaluated the environmental friendly synthesis of Silver nitrate nanomaterials (SNM) from the active marine Streptomyces strain Al-Dhabi-91 isolated from the Dammam region of Saudi Arabia. The obtained SNM was chemically characterized by various spectroscopic techniques such as UV, XRD, FTIR, SEM, TEM and EDAX; and its biological applications such as antimicrobial properties and antioxidant potential were recorded by DPPH methods. Biochemical and micromorphological studies together with the molecular techniques confirmed that the isolate Al-Dhabi-91 belonged to Streptomyces species. The characterization techniques confirmed that the UV spectrum showed maximum absorption peak at 305 nm indicating the plasmodium characteristics. SEM and TEM analyses evidenced 5–2 nm which are agglomerated, cool to form porous asymmetrical networks. Additionally, the FTIR spectrum showed maximum peak at 1194 cm−1 and 1394 cm−1, confirming the presence of aromatic CH bending and aromatic CC bending in the SNM. SNM exhibited prolific antibacterial activity against Gram negative pathogens, K. pneumoniae (28.33 mm) and E. coli (21.66 mm) respectively. The MIC values of SNM were significant with respect to E. faecalis (125 μg/ml), S. aureus (250 μg/ml), P. aeruginosa (125 μg/ml), K. pneumoniae (500 μg/ml) and E. coli (250 μg/ml) respectively. In addition, the antioxidant potential of the SNM was another value added importance. Especially 50 μg/ml of the nanoparticles showed 33% antioxidant potential; similarly in nitric oxide radical inhibition assay the concentration of 50 μg/ml nanoparticles showed 33% of inhibition potential. Overall, the eco-friendly synthesis of SNM from the marine Streptomyces strain Al-Dhabi-91 was an ideal active source for the treatment of infectious disease and health associated disorders.

Alternanthera bicolor Produces Hypoglycemic Effect in Alloxan-Induced Diabetic Mice through its Antioxidant Activity

The current investigation was carried out to evaluate the antioxidant properties of ethanolic extract of Alternanthera bicolor and to assess the potential hypoglycemic effect of the extract in alloxan-induced diabetic mice. HPLC-DAD method was used to determine polyphenolic compounds present in the extract. Different in vitro assays (i.e. DPPH radical scavenging activity test, reducing power test, NO radical inhibition assay and scavenging of hydrogen peroxide) were used to determine the antioxidant potential of the plant. Antidiabetic activity was evaluated in alloxan-induced diabetic mice by glucose tolerance test and standard biochemical analyses. HPLC-DAD analysis of the extract confirmed the presence of (+)-catechin hydrate, caffeic acid, quercetin and kaempferol. A. bicolor showed potent antioxidant activities in DPPH radical, hydrogen peroxide and nitric oxide scavenging assays. Moreover, A. bicolor showed potent reducing power and dose-dependent increment of total antioxidant capacity. Furthermore, the plant showed potent hypoglycemic activities in alloxan-induced diabetic mice. Ethanolic extract of the plant at doses of 200- and 400-mg/kg body weight (administered orally for 3 weeks) significantly decreased the elevated levels of blood glucose, lipid peroxidation product TBARS, hydroperoxides and nitric oxide in experimental animals. Apart from these activities, the ethanolic extract of the plant restored the reduced catalase function in liver. From this study, we can conclude that ethanolic extract of A. bicolor exhibited hypoglycemic and antioxidant activities in alloxan-induced diabetic mice.
 Dhaka Univ. J. Pharm. Sci. 18(1): 49-60, 2019 (June)

Antioxidant and Haematological Activities of Ethanolic Extract of Ricinus communis

Ricinus communis commonly known as castor oil is used as a traditional natural remedy or folkloric herb for the control and treatment of a wide range of diseases around the globe. Various studies have revealed the presence of diverse phytochemicals such as alkaloids, flavonoids, terpenes, saponins, phenolic compounds such as kaempferol, gallic acid, ricin, rutin, lupeol, and ricinoleic acid. The present study investigates the in vivo and in vitro analyses of the effect of ethanolic extract of ricinus communis leaf and seed on animal models. The antioxidant potential of Ethanolic leaf and seed extract of Ricinus communis was investigated. The result shows that the ethanolic extract of the seed and leaf exhibited IC50 values of 77.17± 0.36 and 69.33 ± 0.26 μg/mL, 62.86±0.54 and 62.39±0.18 μg/mL respectively in DPPH and nitric oxide radical inhibition assays these values were less than those obtained for ascorbic acid used as standard. In the in vivo experiments the extract treatment caused a significant increase in the level of catalase in the liver and the kidneys. A significant increase in the level of SOD in the liver was observed. The acute toxicity study was carried out in both male and female wistar rats; the results reveal that even at the highest dose 2000mg/kg body weight R.communis seed and leaf extract showed no significant toxic effects showing that LD50 is above 2000 and belongs to class 5. The haematological and biochemical parameters of the treatment groups were compared with the control group, result shows that there were no significant differences (mean ± SEM n=6 *p < 0.05) in the biochemical and haematological parameters of treatment groups compared to the control group. These findings suggest that the ethanolic extract of Ricinus communis seed and leaf exhibited a strong antioxidant activity which may be responsible for some of its reported pharmacological activities and can be used as antioxidant supplement.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

The novel phytocomponent asiaticoside-D isolated from Centella asiatica exhibits monoamine oxidase-B inhibiting potential in the rotenone degenerated cerebral ganglions of Lumbricus terrestris

Background: Centella asiatica (CA) is one of the most valuable herbal medicines widely being used for the treatment of various neurological ailments that are challenging for health-care providers and also is deemed to be safe and effective.Purpose: Monoamines (MAs) are neurotransmitters and neuromodulators that play a significant role in the neural communication, regulation of motor and cognitive functions in the brain. Neurodegeneration is associated with elevated levels of MAO-B that can lead to damaging reactive oxygen species (ROS) in the brain. The current study, evaluated the effects of asiaticoside-D (AD) from neuroprotective CA, on the levels and activities of monoamine oxidase A and B (MAO-A and B), in addition to the behavioral analysis.Methods: Qualitative and quantitative analyses of various solvent extracts of CA were performed. The extracts were screened for antioxidant potential using 1,1-diphenyl-2-picryl hydroxyl (DPPH), 2,2′-azinobis-3-ethylbenzothiozoline-6-sulfonic acid (ABTS), hydrogen peroxide (H2O2) radical, nitric oxide (NO) radical inhibition, lipid peroxidation (LPO) and ferric reducing antioxidant power (FRAP) assays. The purification of AD was done by column, thin layer and high-performance liquid chromatographies followed by structural elucidation using IR, HR–MS, 1H and 13C NMR spectra. Docking studies were performed to assess the impact of AD on MAO-A and B.In vivo, Lumbricus terrestris were exposed to 0.4 ppm rotenone (ROT) of medium for 7 days and were subjected to co-treatment along with 15 ppm of AD from CA. At the end of experiment period, the neuronal behavior of worms was assessed. Cerebral ganglions (CGs) were removed and the m-RNA levels of MAO-A and B were analyzed by Semi Q-PCR and their activities were also analyzed.Results: The ethanolic extracts exhibited higher antiradical activity against DPPH, ABTS, H2O2, LPO, FRAP, NO and vitamin C with EC50 value of 20.2, 20.9, 20.4, 22.0, 24.9, 28.1, 25.5 and 22.0 µg/ml respectively. Structural analysis by IR, HR-MS, 1H and 13C NMR spectrum have shown the structure of the isolated compound as (2α, 3β)-2,3–dihydroxyurs-12-en-28-oicacid-O-α-L-rhamnopyranosyl-(1→4)-O-β-d-glucopyranosyl (1→6)-β–copyranosyl ester and was represented as AD. In silico interaction of AD with MAO-A and B residues Lys312 at distances of 1.84 Å and 2.44 Å respectively was found to exhibit high binding energy of -9.4 and 7.4 kcal. The neuronal behavior using L. terrestris showed significant improvement against (p < 0.001) ROT impaired behavior (group II) on AD supplementation (p < 0.05). Further, the m-RNA levels and activities of MAO-A and B which were significantly altered (p < 0.001) by ROT could be effectively maintained on AD supplementation.Conclusion: AD was found to exert its negative impact on the levels and activities of MAO-A and B in CGs of rotenone- induced changes in L. terrestris, the property which is considered to be crucial against ROT induced neurodegenerative pathology like -Parkinsonism.

CHEMICAL AND BIOLOGICAL STUDY OF EUGENIA STIPITATA MC VAUGH COLLECTED IN THE COLOMBIAN ANDEAN REGION

Objective: The main objective of this study is to evaluate the chemical and bioactive properties of Eugenia stipitata (Myrtaceae) fruit seeds collected in the Andean region of Colombia using an ethanolic extract, a dichloromethane fraction (DF), and a hydroalcoholic residue.Methods: E. stipitata seeds were evaluated using bromatological analysis; these were macerated (ethanol 96%) and partitioned (dichloromethane). Phytophenols composition of the samples was tested by high-pressure liquid chromatography-mass spectrometry and Folin–Ciocalteu method, then calculated as gallic acid equivalents (GAEs). Antiradical capacity was tested by 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and 3-ethylbenzthiazoline-6- sulfonic acid (ABTS•+) and inhibitory concentration 50% (IC50) was calculated; antioxidant capacity was determined using ferric reducing antioxidant power, oxygen radical absorbance capacity, and OH• radical and hemolysis inhibition assays. Anthelmintic activity against Panagrellus redivivus and ovine gastrointestinal (GI) nematodes and toxicity on human blood cells were tested.Results: E. stipitata seeds contain protein, sulfur, boron, iron, and copper. The ethanolic extract exhibited significant anthelmintic activity against free-living and GI nematodes, which would be associated with the phytophenols content, mostly tannins (29.14 g GAE/100 g). DF displayed the highest antiradical capacity in DPPH• and ABTS•+ (IC50: 2.65 and 0.33 mg/l, respectively) methods, antioxidant capacity, and hemolysis inhibition of human erythrocytes (IC50: 200 mg/l). There were no toxic metabolites to human blood cells.Conclusion: These findings would be useful for promoting the use of E. stipitata seeds, collected in the Colombian Andean region, in biotechnological processes. This is the earliest paper showing a study carried out in Colombia with an interest in evaluating chemical and biological characteristics of E. stipitata seeds.

Interconnected PolymerS TeChnology (IPSTiC): An Effective Approach for the Modulation of 5α-Reductase Activity in Hair Loss Conditions

Hair loss represents a condition that adversely affects the social life of patients. The most common cause is androgenetic alopecia (AGA), which is a genetically determined progressive hair-loss condition involving 5α-reductase. In this study, a novel anti-baldness agent based on Interconnected PolymerS TeChnology (IPSTiC), which is an effective strategy for the delivery of bioactive molecules, was developed. This product (IPSTiC patch hair) is based on a polymeric blend consisting of high molecular weight hyaluronic acid and soybean proteins and is able to improve efficacy and stability of bioactive ingredients such as Origanum vulgare leaf extract, Camellia Sinensis leaf extract, and Capsicum Annuum fruit extract. The efficacy of the developed anti-baldness agent was investigated by performing several tests including NO radical and 5α-reductase inhibition assays, stability studies under different conditions, and in vitro diffusion studies using Franz cells. The biocompatibility of IPSTiC patch hair was also evaluated by in vitro analysis of the pro-sensitising potential and EPISKIN model. The obtained results confirmed both the efficacy and safety of IPSTiC patch hair supporting the potential use of this product in the topical treatment of AGA.

Antioxidant and antibacterial activities of the essential oils obtained from seven Iranian populations of Rosmarinus officinalis

Rosemary (Rosmarinus officinalis) is an aromatic shrub belonging to the Lamiaceae family and widely used as herbal remedy and spices. In this work, the leaf essential oil from seven populations of rosemary growing in Western Iran was obtained by hydrodistillation and analyzed by GC-FID and GC–MS. The major chemical groups occurring in the essential oils were monoterpene ketones (14.55–37.31%), hydrocarbons (28.36–36.81%) and oxygen-containing compounds (9.05–27.60%). The major constituents of the essential oils were 1,8-cineole (5.63–26.89%), camphor (1.66–24.82%) and α-pinene (14.69–20.81%). The essential oils were screened for antibacterial and antioxidant activities. The antibacterial activity of the essential oils was evaluated on two gram-positive and two gram-negative strains, namely Streptococcus agalactiae, Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae by the agar disc diffusion method. Results of antibacterial test indicated that the largest inhibition (inhibition zone of 18.51mm) was achieved with essential oil from Ma population against E. coli. This sample showed high level of 1,8-cineole. Antioxidant activity of the essential oils was evaluated using the DPPH radical inhibition assay (at 0.4, 0.8, 1.6 and 3.2mg/ml). Overall, the essential oils from the seven populations, at 3.2mg/ml, exhibited high antioxidant activity (more than 50% radical inhibition). Statistical analysis revealed a significant correlation between some essential oil components and biological activity displayed.

Phytochemical Evaluation and In vitro Antioxidant Activity of Various Solvent Extracts of Leucas aspera (Willd.) Link Leaves

Background: Free radicals initiate the oxidative stress and damage the healthy cells. These damages contribute ageing, cancer, cardiovascular and inflammatory diseases. Phenolic compounds, flavonoids and tannins are directly contributed to antioxidant activity. Objective: The present study was attempted to evaluate the phytochemicals present in various solvent extracts obtained from Leucas aspera (Willd) Link leaves (L. aspera) and its antioxidant activity using different in-vitro models. Materials and Methods: The free radical scavenging and antioxidant activity of petroleum ether, ethanol, isopropyl alcohol, ethyl acetate and chloroform extracts of L. aspera leaves were assessed by different in-vitro models include DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging capacity, total antioxidant activity, ABTS (2,2,-azinobis (3-ethylbenzoline-6-sulfonic acid) radical scavenging activity and nitric oxide radical inhibition assay, in order to ensure the pharmacological effects of the plant. Results: Petroleum ether extract (non-polar solvent) showed better antioxidant activity among the solvents with IC50 values 18.96 μg/mL (DPPH assay), 17.22 μg/mL (total antioxidant assay), 16.00 μg/mL (ABTS assay) and 11.87 μg/mL (nitric oxide scavenging). Whereas, ethanol extract (polar solvent) exhibited better DPPH scavenging, ABTS assay and nitric oxide scavenging activity (IC50=19.90, 11.60 and 13.47 μg/mL respectively) compared to chloroform, ethyl-acetate and isopropyl alcohol extracts. Conclusion: The results of our current study showed, L. aspera leaf is a significant source of phytochemicals that possess antioxidant and scavenging properties. Our study findings warrants for various pharmacological activities and further research on isolation and characterization of active principle responsible for the pharmacological activity.

Quality and Antioxidant Activity of Yogurt Supplemented with Roselle during Cold Storage

The purpose of this study was to determine the quality (physical, chemical, microbiological characteristics), total phenolic content, and antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) inhibition assay of probiotic yogurt supplemented with roselle flower extract (Hibiscus sabdariffa L) during cold storage. The experiment used treatment for types of yogurt as follows: cow’s milk probiotic yogurt + roselle, goat’s milk probiotic yogurt + roselle, cow’s milk yogurt, and goat’s milk yogurt. The yogurt was stored in cold storage and evaluated the quality and antioxidant activity variables on days 0, 3, 6, 9, 12, and 15th. The results showed that there were interaction (P<0.05) between types of yogurt and storage time on pH value and total lactic acid bacteria (LAB), but no interaction effect on viscosity. The types of yogurt significantly affected (P<0.05) aw, total titrable acid (TTA), total phenolic content, and antioxidant activity. Cow’s milk probiotic yogurt + roselle and goat’s milk probiotic yogurt + roselle were the best yogurt that contributed to a good quality and high antioxidant activity up to 15 d at cold storage.

Profiling of polyphenolics, nutrients and antioxidant potential of germplasm’s leaves from seven cultivars of Moringa oleifera Lam.

This work compares the polyphenolics composition, antioxidant activity and contents of selected nutrients in the leaves from seven cultivars of Moringa oleifera (‘Tumu’, ‘Sunyaw’, ‘Kumasi’, ‘Techiman’, ‘China’, ‘Pakistan Black’, and ‘Pakistan White’) representing the variety in Pakistan. Both the non-enzymatic (DPPH free radical and linoleic acid peroxidation inhibition assays) and enzymatic (superoxide dismutase, peroxidase, and catalase activities) antioxidant capacity was appraised. Regarding the nutritional value, in terms of protein and minerals contents, minor differences were recorded among cultivars. HPLC-PDA-ESI-MSn analysis of the hydro-methanolic extracts of Moringa leaves revealed a wide range of phenolics, highlighting their content in kaempferol derivatives, caffeoylquinic acid, and feruloylquinic acid. The antioxidant capacity of the tested leaves was correlated with the individual phenolics composition in order to identify which compounds were responsible for this beneficial power. The varying (p<0.05) concentration of phenolics together with the antioxidant capacity of the tested leaves established ‘Pakistan Black’ and ‘Techiman’ as the most nutritive cultivar among others to be grown in the local area. Moreover, these data support the relevance of genetic variability of Moringa for determining the aptitude as a source of beneficial phenolics and nutrients, allowing to identify the optima cultivars to be grown in southern Asia.

In vitro evaluation of antioxidant and antidiabetic activities of Syzygium densiflorum fruits

ABSTRACT Objective To provide experimental support for the traditional knowledge of Syzygium densiflorum ( S. densiflorum ) fruits. Methods Powered S. densiflorum dried fruits were subjected to successive extraction with n -hexane, ethyl acetate, and ethanol using a Soxhlet extractor. Further, preliminary phytochemical screening was carried out with a series of tests. In vitro free radical scavenging was evaluated using total antioxidant estimation, 2,2-diphenyl-1-picrylhydrazyl radical, superoxide radical scavenging, and hydroxyl radical scavenging assays. Antidiabetic activity was estimated using α-amylase inhibition assay. Results Preliminary phytochemical estimation confirmed the presence of alkaloids, flavonoids, sterols, terpenoids, anthocyanin, phenols, carbohydrates, fixed oils, and fats in fruits of S. densiflorum . Ethyl acetate and n -hexane extracts showed less free radical scavenging and α-amylase inhibition activity than ethanol extract. IC 50 values of ethanol extracts for 2,2-diphenyl-1-picrylhydrazyl radical, superoxide radical, hydroxyl radical, lipid peroxidation, and α-amylase inhibition assays were found to be 0.01, 0.16, 0.66, 0.46, and 0.46 mg/mL respectively. Conclusions In vitro evaluations confirmed the antioxidant and antidiabetic potential of S. densiflorum fruits. Ethanol extract of S. densiflorum fruits showed higher activity with statistical significance vs. ethyl acetate and n -hexane extracts.

&lt;I&gt;In Vitro&lt;/I&gt; &amp;#945;-Glucosidase Inhibition and Antioxidant Activity of &lt;I&gt;Walsura trifoliata&lt;/I&gt; (A. Juss.) Harms

Walsura trifoliata is being used in traditional system of medicine with scant scientific documentation. This report is an attempt to provide laboratory findings in support of its traditional use. The crude extract of the root prepared with the solvent systems hexane, ethyl acetate and methanol were used separately for its α–glucosidase inhibition, phenolic contents, reducing ability assay and antioxidant activities. The antioxidant property of the crude extracts were tested using DPPH Radical Scavenging Assay, Hydroxyl Radical Scavenging Assay, Nitric Oxide Radical Inhibition Assay, Superoxide Scavenging Activity, Inhibition of Lipid Peroxidation and Ferric Reducing Antioxidant Power. Among the solvent preparations, the methanol extract of the root of Walsura trifoliata showed the maximum inhibitory activity for α–glucosidase inhibition with the IC50 value 690 ± 1.44 µg/ml. The IC50 value for the methanol extract in DPPH Radical Scavenging Assay was 620 ± 1.99 µg/ml. Among all the parameters studied, methanol extract showed the maximum activity while minimum activity was recorded in hexane extract.Keywords: Walsura trifoliata, α–Glucosidase Inhibition, Antioxidant, Medicinal Plant

Antioxidant activity and viability of lactic acid bacteria in soybean-yogurt made from cow and camel milk

In the present study soybean (Glycine max L.) was included in cow and camel milk during fermentation. The resulting soybean-yogurt was evaluated with respect to the changes of post-acidification, viable cell counts (VCC) of Lactobacillus spp. and Streptococcus thermophilus, total phenolic content (TPC) and antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) inhibition assay during 21 days of refrigerated storage. The presence of soybean in fresh cow- and camel-milk yogurts did not affect pH reduction compared to respective plain-yogurt. However, soybean–camel milk yogurt showed significant reduction in pH (4.05±0.06) compared to plain-yogurt 4.35±0.02 on day 7 of storage. Titratable acidity (TA) increased in soybean–cow milk yogurt (p<0.05) but not in soybean–camel milk yogurt as compared with respective plain-yogurt during period of storage. The presence of soybean in fresh yogurt showed increased (p<0.05) in Lactobacillus spp. VCC by 10% in cow milk-yogurt and 30% in camel milk-yogurt compared to respective plain-yogurts. On the other hand, VCC of S. thermophilus was higher (p<0.05) in the presence of soybean in cow milk yogurt than in camel milk yogurt. Soybean–camel milk yogurt had 2-folds higher TPC on day 0 and 7 (149.59±1.8 and 111.44±2.8μgGAE/ml respectively) than plain-camel milk yogurt (60.04±0.01 and 55.22±0.01μgGAE/ml respectively). The highest value of TPC in soybean–cow milk-yogurt was showed on day 21 of storage (43.17±1.2μgGAE/ml). The antioxidant activity increased (p<0.05) in the presence of soybean in both cow and camel milk yogurts compared to respective controls. The highest antioxidant activity was shown on day 0 for soybean–cow milk yogurt (61.76±2.2%) and day 7 for soybean–camel milk yogurt (53.16±0.1%). In conclusion, the addition of soybean in both cow- and camel-milk yogurts enhanced the viability of LAB and antioxidant activity during refrigerated storage.

Phytochemical Content, Radical Scavenging and Antibacterial Properties of Aqueous Extract of Jatropha curcas Linn Leaves

This study investigated phytochemical content, radical scavenging and antibacterial activities of aqueous extract of leaves of Jatropha curcas Linn. Quantitative phytochemical analyses of alkaloids, phenols, tannins and flavonoids contents were carried out; radical scavenging activity was assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and hydrogen peroxide inhibition assays while Disc diffusion and Agar well (ditch) diffusion methods were used for antibacterial activity against Klebsiella pneumonia, Escherichia coli, Pseudomonas aeruginosa, Staphilococcus aureus and Proteus species at 62.5, 125, 250 and 500 mg/mL. The extract contained alkaloids (1.600± 0.58 %), tannins (0.121 ± 0.00 mg/mL), phenols (0.463 ± 0.06 mg/mL) and flavonoids (0.672 ± 0.00 mg/mL), and showed radical scavenging activities against DPPH (IC50 = 21.24) and hydrogen peroxide (15.67 mg/mL) which were less than that of Butylated hydroxyanisole (BHA); IC50 = 3.92 (DPPH) and 6.19 mg/mL (hydrogen peroxide) respectively. It also showed antibacterial activity against Klebsiella pneumonia, Escherichia coli, and Pseudomonas aeruginosa at 250 and 500 mg/ml (MIC = 125 mg/mL), which were resistant to ampicillin, chloxacillin and erythromycin, and the extract was inactive against Staphilococcus aureus and Proteus species at these concentrations, though all were sensitive to gentamycin. This shows that the aqueous extract of leaves of Jatropha curcas Linn may possess some of the folkloric properties claimed.

Improvement of antioxidant activity of peptides with molecular weights ranging from 1 to 10 kDa by PEF technology

Egg white protein powder was hydrolyzed with Alcalase to produce antioxidant peptides. Then, the peptides were fractionated with ultrafiltration membranes. The peptides (1–10kDa) were further treated by pulsed electric field (PEF) to investigate its effect on the antioxidant activity of the peptides. Antioxidant activity was evaluated using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical inhibition assay. The results indicated that optimal electric field intensity and standing times of PEF can enhance the antioxidant activity of the peptides. Therefore, a Box-Behnken design (BBD) with three independent variables including concentration, electric field intensity and pulse frequency was used to establish the regression equation of second-order response surface. The optimal conditions were as follows: concentration 8mg/ml, electric field intensity 10kV/cm and pulse frequency 2400Hz. Under these conditions, the peptides antioxidant activity was 62.64%±0.98%. The present study demonstrated that the antioxidant activity of peptides (1–10kDa) could be improved using PEF.

HPLC Method for Chemical Composition and In vitro Antioxidant Activity of Camellia sinensis Linn.

Chemical composition and antioxidant properties of green tea extract (Camellia sinensis L.) are presented in this study. Yield of extract was quantified (5.31±0.91%). Total phenol content was estimated as gallic acid equivalents (485±43 mg/g) and total flavonoid content was estimated (133.41±4.04 mg of catechin/g of extract). Qualitative-quantitative composition of the extract was determined by high performance liquid chromatography coupled with photodiode array detection and total phenols found to be 46.81±0.07 (epigallocatechin (8.O1±0.12%), catechin (1.74±0.08%), epicatechin (3.04±0.12 %), epigallocatechin-3gallate (16.42±0.05%), gallocatechingallate (12.98±0.08%) and epicatechin-3-gallate (4.62±0.22%)). Free radical scavenging activity of the extract was determined by both 1,1-diphenyl-2-picrylhydrazyl assay (IC50=4.57 μg/ml) and ABTS radical inhibition (IC50 2.50 μg/ml) assay. Oxygen radical absorbance capacity (165.34±4.28 μmol of Trolox equivalent (TE)/g of fresh weight) and total antioxidant capacity (707.30±12.14 mg ascorbic acid equivalent/g) of the extract were determined. Reducing power of the extract was found to be 1.976±0.013 absorbance unit at 120 μg/ml. The results obtained from the present study indicate that green tea extract is a potential source of natural antioxidant with multimodal activities.

Evaluation of antioxidant activity of Tetracarpidium conophorum (Müll. Arg) Hutch & Dalziel leaves.

This study evaluated the antioxidant activity as well as bioflavonoid content of the methanol and ethanol-water extracts of the fresh and dried leaves of Tetracarpidium conophorum. Antioxidant activity was determined by spectrophotometric methods using DPPH free radical, nitric oxide radical inhibition and ferric reducing antioxidant power assays. In addition, total phenolics, flavonoids and proanthocyanidin content were also determined. The ethanol: water extract of the dried leaves had the highest antioxidant activity with a 50% inhibition of DPPH at a concentration of 0.017 mg/mL compared to the standards, Vitamin C and Vitamin E with inhibition of 0.019 and 0.011 mg/mL, respectively. This extract also showed nitric oxide radical inhibition activity comparable to that of rutin, 54.45% and 55.03% for extract and rutin, respectively, at 0.1 mg/mL. Ferric reducing power was also comparable to that of ascorbic acid (281 and 287 μM Fe (11)/g, resp.) at a concentration of 1 mg/mL. The methanol extract of both the dried and the fresh leaves had higher phenolic, flavonoids and proanthocyanidin content than the ethanol : water extract. The study reveals that T. conophorum can be an interesting source of antioxidants with their potential use in different fields namely food, cosmetics and pharmaceuticals.

Flavonoid glycosides in the shoot system of Okinawa Taumu (Colocasia esculenta S.)

Six C-glycosylflavonoids and one O-glycosylflavonoid have been isolated from the shoot system of Taumu (Colocasia esculenta S.). They were identified as schaftoside, isoschaftoside, orientin, isovitexin, isoorientin, vitexin and luteolin 7-O-sophoroside. The presence of catechol moiety in the B-ring of isoorientin, orientin and luteolin 7-O-sophoroside showed strong antioxidant activity with different mechanisms of action in DPPH radical scavenging, β-carotene bleaching and superoxide radical inhibition assays. The amount of dry weight matter extract of water was higher than methanol for both the leaf and the stem parts. Isovitexin was the main compound in water and methanol extracts of the leaf while schaftoside was the main compound of the water extract of the stem. Methanol extract of the leaf showed higher DPPH radical scavenging activity than water extract while the opposite was observed for the stem. The results of this experiment suggest the potential of the leaf of Taumu as a source of dietary antioxidant.

Physicochemical characterization and antioxidant activity of a polysaccharide isolated from oolong tea

Oolong tea polysaccharide (OTPS) is a kind of water-soluble polysaccharide isolated from oolong tea. Its molecular weight, composition, and structure were analyzed by laser light scattering analysis, chemical methods, gas chromatography, and atomic force microscopy (AFM). Antioxidant potential was detected by hydroxyl radical scavenging, inhibition of lipid peroxidation, DPPH radical scavenging, and reducing power assays. Results showed that OTPS was a non-reductive acid heteropolysaccharide bound to protein. The amounts of uronic acid, protein and neutral sugar in OTPS were 40.65, 19.59, and 26.66%, respectively. The neutral sugar was composed of d-rhamnose, l-arabinose, d-galactose, and d-glucose with a molar ratio of 1.37:1.89:1.00:1.30. The molecular weight of OTPS was 1.28 × 106 Da and the second viral coefficient was 2.36 × 10−4 cm3 mol/g2. A globular image of OTPS was imaged by AFM. OTPS showed effective antioxidant activities on hydroxyl radical scavenging assay and inhibition assay of lipid peroxidation.