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Molecularly imprinted polymer synthesis using RAFT polymerisation

Peter A.G. Cormack, Faizatul Shimal Mehamod

Sains Malaysiana, 2013;42:529-535.

In this paper, the synthesis and characterisation of caffeine-imprinted polymers are described. The polymers were prepared in monolithic form via both reversible addition-fragmentation chain-transfer (RAFT) polymerisation and conventional free radical polymerisation, using methacrylic acid and ethylene glycol dimethacrylate as the functional monomer and crosslinking agent, respectively. The potential benefits in applying RAFT polymerisation techniques towards the synthesis of molecularly imprinted polymers (MIPs) are explored and elucidated. The pore structures of the polymers produced were characterised by nitrogen sorption porosimetry and the molecular recognition properties of representative products were evaluated in high-performance liquid chromatography (HPLC) mode. Molecular imprinting effects were confirmed by analysing the relative retentions of analytes on imprinted and non-imprinted HPLC
stationary phases. It was found that a caffeine-imprinted polymer synthesised by RAFT polymerisation was superior to a polymer prepared using a conventional synthetic approach; the imprinting factor and column efficiency were found to be higher for the former material.

Matched MeSH terms: Free Radicals
Fulltext Cerebral protection: a review of current techniques

Palur, Ravikant

Medical Health Reviews, 2009;2009(1):15-42.
MyJurnal

The brain is considered the most eloquent organ in the human body as its activities impacts on all other systems. Though protected physically (in a bony covering), physiologically through the blood-CSF barrier (from invading organisms and toxins) and hemodynamically through the phenomenon of cerebral autoregulation; the brain is open to insults of various kinds which can critically damage this structure. Intracellular Ca++ accumulation, excessive activation of excitatory amino acid receptors, lipid peroxidation and free radical releaserelated damage are but a few of the pathological processes that occur at the neuronal level leading to damage. The mechanism by which the brain can be provided protection when it is in a compromised state or likely to be compromised is known as cerebral protection. There are various modalities of pharmacologic (use of barbiturates, etomidate, isoflurane, steroids, Ca++, corticosteroids etc) and non-pharmacologic therapies (hypothermia, hyperventilation, induced hypotension, electrophysiologic monitoring, endovascular management etc) available for cerebral protection which finds place in the armamentarium of clinicians managing the critically injured brain. Our knowledge of the functioning of the brain at the molecular level and the various biochemico-pathological processes that are set into motion during critical states continues to evolve. This review article attempts to explain present understanding of the biochemical and pathological processes involved in neuronal damage while also looking at current available therapies (pharmacologic & nonpharmacologic) being utilized in different clinical settings.

Matched MeSH terms: Free Radicals
Fulltext Phytochemistry, pharmacology and toxicology properties of Strobilanthes crispus

Nurraihana, H., Norfarizan-Hanoon, N.A.

International Food Research Journal, 2013;20(5):2045-2056.
MyJurnal

Strobilanthes crispus (S. crispus) is an herbal medicine plant which is native to countries from Madagascar to Indonesia. The plants contained high amount of mineral content and vitamin C, B1 and B2. This plant are used in medicinal and to treat a variety of ailments in the various traditional systems of medicine. Phytochemical investigations have revealed that the plant contain polyphenols, flavonoids, catechins, alkaloids, caffeine, tannins, compounds known to possess multiple health beneficial effects. Preclinical studies have shown that the plant possess antioxidant, free radical scavenging, anticancer, antidiabetic, antimicrobial, wound healing and antiulcerogenic activities. This review presents the comprehensive overview of phytochemical constituents, pharmacological and toxicological properties of S. crispus and to provide preliminary information for future research and for commercial exploitation.

Matched MeSH terms: Free Radicals
Fulltext Effect of blanching on enzyme and antioxidant activities of rambutan (Nephelium lappaceum) peel

Nurhuda, H.H., Maskat, M.Y., Mamot, S., Afiq, J., Aminah, A.

International Food Research Journal, 2013;20(4):1725-1730.
MyJurnal

Rambutan (Nephelium lappaceum) peel is a potential source of antioxidant. As rambutan is a seasonal fruit, a proper heat treatment prior to storage is necessary. Thus, this study was conducted to determine the effect of water and steam blanchings on browning enzymes and antioxidant activities of rambutan peel extracts. Rambutan from the variety of ‘Anak Sekolah’ were peeled and the peel was blanched in boiling water for 0, 2.5, 5 min and by autoclaving for 0, 5, 10 and 15 min. The residual peroxidase (POD) and polyphenoloxidase (PPO) activities, antioxidant activity (2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity), total polyphenol content (TPC) and peel extract colour were determined. The results showed that both water and steam blanchings significantly reduced (p < 0.05) POD and PPO activities. The results also indicated that the increase in the blanching period did not significantly reduce the enzyme activities further. In terms of antioxidant activity, the thermal pretreatment caused no significant difference in the contents of phenolic compounds, as well as the antioxidant capacity of the final product.

Matched MeSH terms: Free Radicals
Fulltext Effect of solvent extraction on antioxidant and antibacterial activities from Quercus infectoria (Manjakani)

Nur Syukriah, A.R., Liza, M.S., Harisun, Y., Fadzillah, A.A.M.

International Food Research Journal, 2014;21(3):1067-1073.
MyJurnal

Bioactive compounds from Quercus Infectoria (manjakani) were extracted with six different types of solvents: 100% methanol, ethanol, acetone, aqueous and 70% methanol and ethanol. High Performance liquid chromatography (HPLC) was used to identify and quantify the active compounds, namely gallic acid and tannic acid. Total phenolics content were determined by Folin-Ciocalteu while antioxidant and antibacterial activity were tested using DPPH free radicals scavenging and disc diffusion assay. The result revealed that aqueous extract contained the highest concentration of bioactive compounds compared to other types of solvents which are 51.14 mg/g sample and 1332.88 mg/g sample of gallic acid and tannic acid respectively.. The highest level of phenolic compound was found in 100% acetone extract (121 mg GAE/g). The results demonstrated that aqueous extract gives the highest antioxidant activity approximately 94.55% while acetone extract gives the largest inhibition zone for disc diffusion assay which is 19.00 mm respectively. The results revealed rich sources of gallic acid and tannic acid in Q. infectoria which might provide a novel source of these natural antioxidant and antibacterial activity.

Matched MeSH terms: Free Radicals
Fulltext Preliminary phytochemical evaluation and vitamin c content of Tolidus (Hornstedtia havilandii (K. Schum) K. Schum) from Sabah

Nur Syafiqah Martang, Nadia Majitol, Farnidah Jasnie, Lo Chor-Wai

Borneo Akademika, 2020;4(4):15-20.
MyJurnal

Most of the plants in the ginger family Zingeberaceae are well-known for their medicinal properties. However, the genus Hornstedtia found in Sabah is less reported. This research aims to investigate the phytochemical constituent and vitamin C content of a fruit, locally known as the Tolidus fruit in Sabah. The dried fruit sample was extracted using three solvents which were water, ethanol and methanol. The phytochemical constituents were determined using standard Colour Test for the presence of alkaloid, flavonoid, saponin and tannin. Then, the content of Vitamin C was determined using the standard Colorimetric Titration and ascorbic acid as standard. The phytochemical evaluation revealed that all three targeted constituents were present in all extracts except for the alkaloid. The vitamin C content was determined in both dried and fresh sample of fruits, where 52.84 mg was quantified in the fresh fruit aqueous extract and 23.93 mg in the dried fruit aqueous extract respectively. These results are comparable to the content of vitamin C in orange and lime fruits. The phytochemical evaluation and vitamin C content of Tolidus suggested the potential of this underutilised fruit to be the natural and affordable source of vitamin C. Additionally, may protect the body against harmful free radicals. However, further analysis is needed to determine other constructive natural contents and evaluate the efficacy of this fruit as a natural source of antioxidant

Matched MeSH terms: Free Radicals
UV-VIS spectral evaluation of CR-39 detector exposed with diagnostic dosage

Nur Sha'dah Z, Iskandar S, Azhar A, Suhaimi M, Nur Lina R, Halimah M

Sains Malaysiana, 2014;43:953-958.

The effects of the X-ray irradiation and chemical etching on the physical and optical properties of cR-39 plastic detectors were investigated for different doses of X-ray. cR-39 detectors were etched in the solution of the 3 M of NaOH after irradiation for revelations of the track. The tracks formed on cR-39 either by irradiated X-ray or due to the effect of environment. The changes in the thickness after exposed have significant decrease in 60 kVp and started to increase in the range of 70 kVp up to 100 kVp due to the formation of oxidation layer on surface by free radicals. The optical band gaps before etching and after etching were determined by using Ultraviolet-visible (uv-Vis) spectroscopy. The optical band gap is attributed to the indirect transition due to its amorphous nature which is significantly decline trend energy in increase of the energy fluence of radiation. The Urbach's energy, is defined as the width of the tail localized states in the forbidden band gap which change increment trend as increase in dose delivered due to the distortion structure of the cR-39 in terms of the electron charges in valences electron hence attributes to the induced modification of angle bond between the neighboring atoms.

Matched MeSH terms: Free Radicals
Fulltext Quantification of total phenolics in different parts of Pluchea indica (less) ethanolic and water extracts

Normala, H., Suhaimi, M.I.

Pertanika Journal of Science & Technology, 2011;19(1):19-24.
MyJurnal

One of the compounds present in Pluchea indica extracts is antioxidant which plays an important role in inhibiting free radicals and thus protects humans against infections and degenerative diseases, such as cancer, arthritis, and ageing process. The main objective of this study was to investigate and determine the total phenolic compounds of Pluchea indica in different concentrations of ethanolic extracts. This species was chosen because of its high phytonutrient compounds with potential medicinal properties. There was a significant difference (P ≤ 0.05) in the total phenolic among the different parts of the tested plant. 50% of the ethanolic extract produced the highest total phenolic compounds (1775.00±86.00 to 658.95±5.00 µmol/g), followed by water extract (759.79±1.53 µmol/g) and 100% ethanol extract (352.72±22.30 to 249.29±5.37 µmol/g), respectively. In terms of the plant parts, the leaves contained the highest phenolic compounds (1775.00±86.00 µmol/g in 50% ethanol extract, 759.79±1.53 µmol/g in 100% aqueous extract and 352.72±22.30 µmol/g in 100% ethanol extract), followed by the stems (990.22±24.00 µmol/g in 50% ethanol extract, 990.22±24.59 µmol/g in 100% aqueous extract and 293.48±0.00 µmol/g in 100% ethanol extract). Meanwhile, lower total phenolic compounds were detected in the flowers (727.71±11.00 µmol/g in 50% ethanol extract, 603.81±8.46 µmol/g in 100% aqueous extract and 249.29±5.37 µmol/g in 100% ethanol extract) and roots (658.95±5.00 µmol/g in 50% ethanol extract, 450.00±10.76 µmol/g in 100% aqueous extract and 272.28±0.53 µmol/g in 100% ethanol extract). Based on these findings, Pluchea indica has potential medicinal properties that can be further developed to produce neutraceutical products, diet supplements or cosmetic products. However, further research should first be conducted on the effects of these compounds on laboratory animals.

Matched MeSH terms: Free Radicals
Fulltext Effect of Cosmos caudatus kunth. (ulam raja) aqueous and dry extracts on the physicochemical and functional properties, and sensory acceptability of herbal yellow alkaline noodles

Norlaili, A.H., Roselina, K., Muhammad, T.S.

Malays J Nutr, 2014;20(3):403-415.
MyJurnal

Introduction: Cosmos caudatus (Ulam Raja) is rich in phytochemicals and can be utilised in diet diversification strategies to improve the health of individuals. lbis study was designed to incorporate dry and aqueous extracts of C. caudatus for the preparation of herbal noodles. Methods: For this purpose, different proportions of dry extract (2, 4 and 6% dry extract) and aqueous extract (5, 10 and 15% aqueous extract) of C. caudatus were used. The physicochemical properties of noodles evaluated were pH, cooking time, cooking loss, texture and colour. Total polyphenol contents (TPq and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay were carried out to assess the antioxidant potential. Lastly, sensory appraisal of functional noodles was carried out to assess consumer acceptance and marketability. Results: The results on physicochemical properties indicated that the pH value of noodles varied from 8.66 to 10.47. In terms of textural analysis and colour properties, firmness and greenness (a*) were higher in dry extract noodles. TPC varied between 115to149 mg gallic acid equivalents (GAE/lOOg) whilst the highest DPPH free radical inhibition was exhibited in herbal noodles prepared using 4% dry extract (92.8%). In contrast, in terms of sensory appraisal, herbal noodles prepared with aqueous extract were more acceptable than dry extract noodles. Conclusion: C. caudatus can be utilised to prepare herbal noodles thus enhancing the dietary intake of phytochemicals especially antioxidants. Such functional foods can improve the health of consumers and offer the potential of protection against various ailments.

Matched MeSH terms: Free Radicals
Rapid Nucleation of Reduced Graphene Oxide-Supported Palladium Electrocatalysts for Methanol Oxidation Reaction

Ng JC, Tan CY, Ong BH, Matsuda A, Basirun WJ, Tan WK, et al.

J Nanosci Nanotechnol, 2019 Nov 01;19(11):7236-7243.
PMID: 31039881 DOI: 10.1166/jnn.2019.16717

Small sized electrocatalysts, which can be obtained by rapid nucleation and high supersaturation are imperative for outstanding methanol oxidation reaction (MOR). Conventional microwave synthesis processes of electrocatalysts include ultrasonication, stirring, pH adjustment, and microwave irradiation of the precursor mixture. Ethylene glycol (EG), which serves as a reductant and solvent was added during the ultrasonication or stirring stage. However, this step and pH adjustment resulted in unintended multi-stage gradual nucleation. In this study, the microwave reduction approach was used to induce rapid nucleation and high supersaturation in order to fabricate small-sized reduced graphene oxide-supported palladium (Pd/rGO) electrocatalysts via the delayed addition of EG, elimination of the pH adjustment step, addition of sodium carbonate (Na₂CO₃), prior microwave irradiation of the EG mixed with Na₂CO₃, and addition of room temperature precursor mixture. Besides its role as a second reducing agent, the addition of Na₂CO₃ was primarily intended to generate an alkaline condition, which is essential for the high-performance of electrocatalysts. Moreover, the microwave irradiation of the EG and Na₂CO₃ mixture generated highly reactive free radicals that facilitate rapid nucleation. Meanwhile, the room temperature precursor mixture increased supersaturation. Results showed improved electrochemically active surface area (78.97 m² g-1, 23.79% larger), MOR (434.49 mA mg-1, 37.96% higher) and stability.

Matched MeSH terms: Free Radicals
Fulltext Involvement of inflammation and adverse vascular remodelling in the blood pressure raising effect of repeatedly heated palm oil in rats

Ng CY, Kamisah Y, Faizah O, Jubri Z, Qodriyah HM, Jaarin K

Int J Vasc Med, 2012;2012:404025.
PMID: 22778962 DOI: 10.1155/2012/404025

Oil thermoxidation during deep frying generates harmful oxidative free radicals that induce inflammation and increase the risk of hypertension. This study aimed to investigate the effect of repeatedly heated palm oil on blood pressure, aortic morphometry, and vascular cell adhesion molecule-1 (VCAM-1) expression in rats. Male Sprague-Dawley rats were divided into five groups: control, fresh palm oil (FPO), one-time-heated palm oil (1HPO), five-time-heated palm oil (5HPO), or ten-time-heated palm oil (10HPO). Feeding duration was six months. Blood pressure was measured at baseline and monthly using tail-cuff method. After six months, the rats were sacrificed and the aortic arches were dissected for morphometric and immunohistochemical analyses. FPO group showed significantly lower blood pressure than all other groups. Blood pressure was increased significantly in 5HPO and 10HPO groups. The aortae of 5HPO and 10HPO groups showed significantly increased thickness and area of intima-media, circumferential wall tension, and VCAM-1 than other groups. Elastic lamellae were disorganised and fragmented in 5HPO- and 10HPO-treated rats. VCAM-1 expression showed a significant positive correlation with blood pressure. In conclusion, prolonged consumption of repeatedly heated palm oil causes blood pressure elevation, adverse remodelling, and increased VCAM-1, which suggests a possible involvement of inflammation.

Matched MeSH terms: Free Radicals
alpha-Tocopherol increased nitric oxide synthase activity in blood vessels of spontaneously hypertensive rats

Newaz MA, Nawal NN, Rohaizan CH, Muslim N, Gapor A

Am J Hypertens, 1999 Aug;12(8 Pt 1):839-44.
PMID: 10480480

Antioxidant protection provided by different doses of alpha-tocopherol was compared by determining nitric oxide synthase (NOS) activity in blood vessels of spontaneously hypertensive rats (SHR) treated with alpha-tocopherol. SHR were divided into four groups namely hypertensive control (C), treatment with 17 mg of alpha-tocopherol/kg diet (alpha1), 34 mg of alpha-tocopherol/kg diet (alpha2), and 170 mg of alpha-tocopherol/kg diet (alpha3). Wister Kyoto (WKY) rats were used as normal control (N). Blood pressure were recorded from the tail by physiography every other night for the duration of the study period of 3 months. At the end of the trial, animals were sacrificed. The NOS activity in blood vessels was measured by [3H]arginine radioactive assay and the nitrite concentration in plasma by spectrophotometry at wavelength 554 nm using Greiss reagent. Analysis of data was done using Student's t test and Pearson's correlation. The computer program Statistica was used for all analysis. Results of our study showed that for all the three alpha-tocopherol-treated groups, blood pressure was significantly (P < .001) reduced compared to the hypertensive control and maximum reduction of blood pressure was shown by the dosage of 34 mg of alpha-tocopherol/kg diet (C: 209.56 +/- 8.47 mm Hg; alpha2: 128.83 +/- 17.13 mm Hg). Also, NOS activity in blood vessels of SHR was significantly lower than WKY rats (N: 1.54 +/- 0.26 pmol/mg protein, C: 0.87 +/- 0.23 pmol/mg protein; P < .001). Although alpha-tocopherol in doses of alpha1, alpha2, and alpha3 increased the NOS activity in blood vessels, after treatment only that of alpha2 showed a statistical significance (P < .01). Plasma nitrite concentration was significantly reduced in SHR compared to normal WKY rats (N: 54.62 +/- 2.96 mol/mL, C: 26.24 +/- 2.14 mol/mL; P < .001) and accordingly all three groups showed significant improvement in their respective nitrite level (P < .001). For all groups, NOS activity and nitrite level showed negative correlation with blood pressure. It was significant for NOS activity in hypertensive control (r = -0.735, P = .038), alpha1 (r = -0.833, P = .001), and alpha2 (r = -0.899, P = .000) groups. For plasma nitrite, significant correlation was observed only in group alpha1 (r = -0.673, P = .016) and alpha2 (r = -0.643, P = .024). Only the alpha2 group showed significant positive correlation (r = 0.777, P = .003) between NOS activity and nitrite level. In conclusion it was found that compared to WKY rats, SHR have lower NOS activity in blood vessels, which upon treatment with antioxidant alpha-tocopherol increased the NOS activity and concomitantly reduced the blood pressure. There was correlation of lipid peroxide in blood vessels with NOS and nitric oxide, which implies that free radicals may be involved in the pathogenesis of hypertension.

Matched MeSH terms: Free Radicals/metabolism
Role of ambrisentan (selective endothelin-A receptor antagonist) on cigarette smoke exposure induced cognitive impairment in Danio rerio

Muthuraman A, Nafisa K, Sowmya MS, Arpitha BM, Choedon N, Sandy CD, et al.

Life Sci, 2019 Mar 04.
PMID: 30844374 DOI: 10.1016/j.lfs.2019.03.002

BACKGROUND: Cigarette smoke is exogenous modifiable factors to changes the neurovascular complication. The chronic exposure of cigarette smoke enhances neurocognitive dysfunction.
AIMS: The present study is focused on evaluating the role of ambrisentan (selective endothelin-A receptor antagonist) on cigarette smoke-induced cognitive impairment in Danio rerio.
MAIN METHODS: The cognitive dysfunction was developed by cigarette smoke exposure (CSE; 10 min in 25 ml of CSE per day) for five days. The selective endothelin-A receptor antagonist i.e., ambrisentan (2.5 to 5 mg/kg; i.p. for five consecutive days) was used for testing of CSE induced cognitive dysfunction. In addition, treatment of reference drug i.e., donepezil (10 mg/kg; i.p. for five consecutive days) was used for this cognitive function study. The cognitive functions were assessed by light and dark chamber; color recognition; partition preference; horizontal compartment; and T-Maze tests. Further, the CSE induced biomarkers changes of the zebrafish brain samples were estimated.
KEY FINDINGS: The treatment of ambrisentan showed a potential ameliorative effect against the CSE induced cognitive functions along with attenuation of biochemical changes. The results are comparable to donepezil-treated groups.
SIGNIFICANCE: Therefore, ambrisentan can be considered for the attenuation of CSE induced impairment neurocognitive functions due to its reduction of free radical scavenging and neuroinflammatory actions as well as regulation of cholinergic neurotransmitter functions.

Matched MeSH terms: Free Radicals
Fulltext In Vitro Wound Healing Potential of Stem Extract of Alternanthera sessilis

Muniandy K, Gothai S, Tan WS, Kumar SS, Mohd Esa N, Chandramohan G, et al.

Evid Based Complement Alternat Med, 2018;2018:3142073.
PMID: 29670658 DOI: 10.1155/2018/3142073

Impaired wound healing is one of the serious problems among the diabetic patients. Currently, available treatments are limited due to side effects and cost effectiveness. In line with that, we attempted to use a natural source to study its potential towards the wound healing process. Therefore, Alternanthera sessilis (A. sessilis), an edible and medicinal plant, was chosen as the target sample for the study. During this investigation, the wound closure properties using stem extract of A. sessilis were analyzed. Accordingly, we analyzed the extract on free radical scavenging capacity and the cell migration of two most prominent cell types on the skin, human dermal fibroblast (NHDF), keratinocytes (HaCaT), and diabetic human dermal fibroblast (HDF-D) to mimic the wound healing in diabetic patients. The bioactive compounds were identified using gas chromatography-mass spectrometry (GC-MS). We discovered that the analysis exhibited a remarkable antioxidant, proliferative, and migratory rate in NHDF, HaCaT, and HDF-D in dose-dependent manner, which supports wound healing process, due to the presence of wound healing associated phytocompounds such as Hexadecanoic acid. This study suggested that the stem extract of A. sessilis might be a potential therapeutic agent for skin wound healing, supporting its traditional medicinal uses.

Matched MeSH terms: Free Radicals
Fulltext Optimal antioxidant activity with moderate concentrations of Tocotrienol rich fraction (TRF) in in vitro assays

Muid, S., Ali, A.M., Yusoff, K., Nawawi, H.M.

International Food Research Journal, 2013;20(2):687-694.
MyJurnal

Vitamin E is known to have potent antioxidant activity and plays an important role in reducing oxidative stress, a pivotal step in atherogenesis. However, several randomised clinical trials using α-tocopherol have failed to demonstrate consistent beneficial effects of antioxidants against atherosclerosis and clinical endpoints. Tocotrienol, a vitamin E compound analogue is shown to have more potent antioxidant activity compared to tocopherol. Finding the optimal anti-oxidative dose is crucial and may effectively be applied for cardioprotection in human. The objective of this study was to determine the optimal dose of tocotrienol rich fraction (TRF) with highest antioxidant activity in vitro using the ferric thiocyanate (FTC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and 2’, 7’- dichlorofluorescein diacetate (DCFHDA) assays. It was found that TRF exhibited potent antioxidant and free radical scavenging activities with an IC50 of 22.10 + 0.01 µg/ml. In all assays, TRF had optimal antioxidant activity at moderate concentrations (10-100 µg/ml). In conclusion, TRF has potent antioxidant activity, which is optimal at moderate concentrations.

Matched MeSH terms: Free Radicals
Fulltext Acuminatol and other antioxidative resveratrol oligomers from the stem bark of Shorea acuminata

Muhammad N, Din LB, Sahidin I, Hashim SF, Ibrahim N, Zakaria Z, et al.

Molecules, 2012 Jul 30;17(8):9043-55.
PMID: 22847143 DOI: 10.3390/molecules17089043

A new resveratrol dimer, acuminatol (1), was isolated along with five known compounds from the acetone extract of the stem bark of Shorea acuminata. Their structures and stereochemistry were determined by spectroscopic methods, which included the extensive use of 2D NMR techniques. All isolated compounds were evaluated for their antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (RSA) and the β-carotene-linoleic acid (BCLA) assays, and compared with those of the standards of ascorbic acid (AscA) and butylated hydroxytoluene (BHT). All compounds tested exhibited good to moderate antioxidant activity in the DPPH assay (IC₅₀s 0.84 to 10.06 mM) and displayed strong inhibition of β-carotene oxidation (IC₅₀s 0.10 to 0.22 mM). The isolated compounds were evaluated on the Vero cell line and were found to be non-cytotoxic with LC₅₀ values between 161 to 830 µM.

Matched MeSH terms: Free Radicals/chemistry
Fulltext Two different isomers of vitamin e prevent bone loss in postmenopausal osteoporosis rat model

Muhammad N, Luke DA, Shuid AN, Mohamed N, Soelaiman IN

Evid Based Complement Alternat Med, 2012;2012:161527.
PMID: 23118785 DOI: 10.1155/2012/161527

Postmenopausal osteoporotic bone loss occurs mainly due to cessation of ovarian function, a condition associated with increased free radicals. Vitamin E, a lipid-soluble vitamin, is a potent antioxidant which can scavenge free radicals in the body. In this study, we investigated the effects of alpha-tocopherol and pure tocotrienol on bone microarchitecture and cellular parameters in ovariectomized rats. Three-month-old female Wistar rats were randomly divided into ovariectomized control, sham-operated, and ovariectomized rats treated with either alpha-tocopherol or tocotrienol. Their femurs were taken at the end of the four-week study period for bone histomorphometric analysis. Ovariectomy causes bone loss in the control group as shown by reduction in both trabecular volume (BV/TV) and trabecular number (Tb.N) and an increase in trabecular separation (Tb.S). The increase in osteoclast surface (Oc.S) and osteoblast surface (Ob.S) in ovariectomy indicates an increase in bone turnover rate. Treatment with either alpha-tocopherol or tocotrienol prevents the reduction in BV/TV and Tb.N as well as the increase in Tb.S, while reducing the Oc.S and increasing the Ob.S. In conclusion, the two forms of vitamin E were able to prevent bone loss due to ovariectomy. Both tocotrienol and alpha-tocopherol exert similar effects in preserving bone microarchitecture in estrogen-deficient rat model.

Matched MeSH terms: Free Radicals
Fulltext Ipomea aquatica crude extract inhibits lipoxygenase, hyaluronidase and xanthine oxidase activities

Muhammad Helmi Nadri, Kian, Kai Cheng, Pei, Ying Ong, Hong, Yeng L., Nor Zalina Othman, Nur Fashya Musa, et al.

Journal of Academia Universiti Teknologi MARA Negeri Sembilan, 2020;8(2):9-14.
MyJurnal

Ipomea aquatica, locally known as water spinach, is one of the most common vegetable consumed by
Malaysian. Based on previous studies, crude extract and phenolic compounds of I. aquatica exhibited
several biological activities including antioxidant, anti-microbial and anti-proliferative. The presence
of phenolic compounds in I. aquatica may contributed to their ability to inhibit enzymes, chelate
metals and scavenge free radicals. Currently, no study reported on anti-inflammatory activity of I.
aquatica with respect to lipoxygenase, hyaluronidase and xanthine oxidase enzymes. The present
study aims to enhance current knowledge on biological properties of I. aquatica crude extract
particularly on anti-inflammatory activity. Three enzymes that involve in inflammatory pathway were
selected in this study including lipoxygenase, hyaluronidase and xanthine oxidase. I. aquatica was
extracted in methanol and tested for lipoxygenase, hyaluronidase and xanthine oxidase at different
concentrations using direct enzyme inhibition assay. Lipoxygenase, hyaluronidase and xanthine
oxidase inhibitory activities of the methanol crude extract increased with increasing
concentration. Highest inhibition activity against lipoxygenase, hyaluronidase and xanthine oxidase
were observed at a concentration of 1000 µg/ml with inhibition of 87.18%, 95.36% and 78.38%,
respectively. Our finding in this study indicates potential anti-inflammatory activity of I. aquatica
crude extract through inhibition of lipoxygenase, hyaluronidase and xanthine oxidase.

Matched MeSH terms: Free Radicals
Fulltext Two-year variations of phenolics, flavonoids and antioxidant contents in acacia honey

Moniruzzaman M, Sulaiman SA, Azlan SA, Gan SH

Molecules, 2013;18(12):14694-710.
PMID: 24287998 DOI: 10.3390/molecules181214694

Honey is a good source of several important chemical compounds and antioxidants and is harvested throughout the year. However, no study has determined how their contents change over the years. The aim of the present research was to investigate the changes in the phenolics, flavonoids and antioxidant properties, as well as other physicochemical properties, of Malaysian acacia honey collected during different months during a two year period. The DPPH (1,1-diphenyl-2-picrylhydrazyl) and FRAP (ferric reducing antioxidant power) methods were used to determine the total antioxidant activity of the honey samples. Generally, honey samples collected in the beginning and the middle of the year tended to have higher sugar content, which may be attributed to its high acidic nature and low moisture content. There was a gradual increase in the phenolic content of the acacia honey samples collected between September 2010 and December 2010. The honey sample collected at the beginning of the year (January) showed the highest color intensity and was dark amber in color. It also contained the highest concentration of phenolic compounds (341.67 ± 2.94 mg(gallic acid)/kg), the highest flavonoid content (113.06 ± 6.18 mg(catechin)/kg) and the highest percentage of DPPH inhibition and the highest FRAP value, confirming its high antioxidant potential. There was a positive correlation between DPPH and total phenolic content, suggesting that phenolic compounds are the strongest contributing factor to the radical scavenging activity of Malaysian acacia honeys. Overall, our results indicated that there were significant seasonal variations in the antioxidant potentials of honey over the two year period and the time of honey collection affects its physicochemical properties. Therefore, acacia honey from Malaysia should ideally be collected during the dry season, particularly in the months of January, May and June.

Matched MeSH terms: Free Radicals/antagonists & inhibitors
Advances in the analytical methods for determining the antioxidant properties of honey: a review

Moniruzzaman M, Khalil MI, Sulaiman SA, Gan SH

Afr J Tradit Complement Altern Med, 2012;9(1):36-42.
PMID: 23983317

Free radicals and reactive oxygen species (ROS) have been implicated in contributing to the processes of aging and disease. In an effort to combat free radical activity, scientists are studying the effects of increasing individuals' antioxidant levels through diet and dietary supplements. Honey appears to act as an antioxidant in more ways than one. In the body, honey can mop up free radicals and contribute to better health. Various antioxidant activity methods have been used to measure and compare the antioxidant activity of honey. In recent years, DPPH (Diphenyl-1-picrylhydrazyl), FRAP (Ferric Reducing Antioxidant Power), ORAC (The Oxygen Radical Absorbance Capacity), ABTS [2, 2-azinobis (3ehtylbenzothiazoline-6-sulfonic acid) diamonium salt], TEAC [6-hydroxy-2, 5, 7, 8-tetramethylchroman-2-carboxylic acid (Trolox)-equivalent antioxidant capacity] assays have been used to evaluate antioxidant activity of honey. The antioxidant activity of honey is also measured by ascorbic acid content and different enzyme assays like Catalase (CAT), Glutathione Peroxidase (GPO), Superoxide Dismutase (SOD). Among the different methods available, methods that have been validated, standardized and widely reported are recommended.

Matched MeSH terms: Free Radicals/metabolism

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