Displaying publications 41 - 60 of 351 in total

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  1. Fulltext Acute toxicity evaluation, antibacterial, antioxidant and immunomodulatory effects of Melastoma malabathricum
    Alnajar ZA, Abdulla MA, Ali HM, Alshawsh MA, Hadi AH
    Molecules, 2012;17(3):3547-59.
    PMID: 22433579 DOI: 10.3390/molecules17033547
    Melastoma malabathricum (MM) is a well-known plant in Malaysian traditional medicine, locally known as senduduk. Its ethanol and aqueous extracts have been used in the present investigation to study the immunomodulatory role on human peripheral blood mononuclear cell (PBMC), and the DPPH, ABTS and FRAP free radical scavenging activities were also measured. Total flavonoids and total phenolic contents were assayed and the antibacterial effect was tested against four species of bacteria; two Gram-positive (Staphylococcus aureus and Streptococcus agalactiae) and two Gram-negative (Escherichia coli and Klebsilla pneumonia). The tests were carried out using the disc diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods. Moreover, the acute toxicity was evaluated in vivo on the ethanol extract of MM to establish its safety when administered orally. In our results, both extracts of MM showed abilities to scavenge DPPH and ABTS free radicals, IC(50) values: (11.599 ± 0.84, 10.573 ± 0.58 µmol/L) and (62.657 ± 0.78, 63.939 ± 0.48 µmol/L) for ethanol and aqueous extracts respectively. Indeed the ethanol extract evidenced high phenolic content (384.33 ± 0.005 mg/g), flavonoids contents (85.8 ± 0.009 mg/g) and ferric reducing antioxidant power (33,590 ± 0.038 mmol/g), with high activity against S. aureus and S. agalactiae (11 ± 0.3 and 12 ± 0.6 mm inhibition zones). Likewise, the percentage of peripheral blood mononuclear cells (PBMC) viability was increased in response to MM, IC(50) values (1.781 ± 1.2 and 6.545 ± 0.93 µg/mL) for ethanol and aqueous extracts, respectively. In addition, our results showed that the MM extract is safe even at a high dose of 5,000 mg/kg and has no oral toxicity. These findings suggest the excellent medicinal bioactivity of MM and explain the popularity of this plant in the folk medicine as a remedy for different illnesses.
    Matched MeSH terms: Antioxidants/chemistry*
  2. Ultrasonically extracted β-d-glucan from artificially cultivated mushroom, characteristic properties and antioxidant activity
    Alzorqi I, Sudheer S, Lu TJ, Manickam S
    Ultrason Sonochem, 2017 Mar;35(Pt B):531-540.
    PMID: 27161557 DOI: 10.1016/j.ultsonch.2016.04.017
    Ganoderma mushroom cultivated recently in Malaysia to produce chemically different nutritional fibers has attracted the attention of the local market. The extraction methods, molecular weight and degree of branching of (1-3; 1-6)-β-d-glucan polysaccharides is of prime importance to determine its antioxidant bioactivity. Therefore three extraction methods i.e. hot water extraction (HWE), soxhlet extraction (SE) and ultrasound assisted extraction (US) were employed to study the total content of (1-3; 1-6)-β-d-glucans, degree of branching, structural characteristics, monosaccharides composition, as well as the total yield of polysaccharides that could be obtained from the artificially cultivated Ganoderma. The physical characteristics by HPAEC-PAD, HPGPC and FTIR, as well as the antioxidant in vitro assays of DPPH scavenging activity and ferric reducing power (FRAP) indicated that (1-3; 1-6)-β-d-glucans of Malaysian mushroom have better antioxidant activity, higher molecular weight and optimal degree of branching when extracted by US in comparison with conventional methods.
    Matched MeSH terms: Antioxidants/chemistry*
  3. Fulltext Changes in the vascular cell adhesion molecule-1, intercellular adhesion molecule-1 and c-reactive protein following administration of aqueous extract of piper sarmentosum on experimental rabbits fed with cholesterol diet
    Amran AA, Zakaria Z, Othman F, Das S, Al-Mekhlafi HM, Nordin NA
    Lipids Health Dis, 2011 Jan 09;10:2.
    PMID: 21214952 DOI: 10.1186/1476-511X-10-2
    BACKGROUND: Inflammation process plays an important role in the development of atherosclerosis. Hypercholesterolemia is one of the major risk factors for atherosclerosis. The present study aimed to evaluate the effect of aqueous extract of Piper sarmentosum (P.s) on inflammatory markers like vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and C-reactive protein (CRP).

    METHODS: Forty two male New Zealand white rabbits were divided equally into seven groups; (i) C- control group fed normal rabbit chow (ii) CH- cholesterol diet (1%cholesterol) (iii) X1- 1% cholesterol with water extract of P.s (62.5 mg/kg) (iv) X2- 1% cholesterol with water extract of P.s (125 mg/kg (v) X3- 1% cholesterol with water extract of P.s (250 mg/kg) (vi) X4- 1% cholesterol with water extract of P.s (500 mg/kg) and (vii) SMV group fed with 1% cholesterol supplemented with simvistatin drug (1.2 mg/kg). All animals were treated for 10 weeks. Blood serum was taken for observing the inflammatory markers at the beginning and end of the experiment.

    RESULTS: Rabbits fed with 1% cholesterol diet (CH) showed significant increase in the level of VCAM-1, ICAM-1 and CRP compared to the C group. The levels of VCAM-1, ICAM-1 and CRP in the 1% cholesterol group and supplemented with P.s (500 mg/kg) were significantly reduced compared to the cholesterol group. Similar results were also reported with simvistatin group.

    CONCLUSION: These results suggest that the supplementation of Piper sarmentosum extract could inhibit inflammatory markers which in turn could prevent atherosclerosis.

    Matched MeSH terms: Antioxidants/chemistry
  4. Colloidal astaxanthin: preparation, characterisation and bioavailability evaluation
    Anarjan N, Tan CP, Nehdi IA, Ling TC
    Food Chem, 2012 Dec 1;135(3):1303-9.
    PMID: 22953858 DOI: 10.1016/j.foodchem.2012.05.091
    Astaxanthin colloidal particles were produced using solvent-diffusion technique in the presence of different food grade surface active compounds, namely, Polysorbate 20 (PS20), sodium caseinate (SC), gum Arabic (GA) and the optimum combination of them (OPT). Particle size and surface charge characteristics, rheological behaviour, chemical stability, colour, in vitro cellular uptake, in vitro antioxidant activity and residual solvent concentration of prepared colloidal particles were evaluated. The results indicated that in most cases the mixture of surface active compounds lead to production of colloidal particles with more desirable physicochemical and biological properties, as compared to using them individually. The optimum combination of PS20, SC and GA could produce the astaxanthin colloidal particles with small particle size, polydispersity index (PDI), conductivity and higher zeta potential, mobility, cellular uptake, colour intensity and in vitro antioxidant activity. In addition, all prepared astaxanthin colloidal particles had significantly (p<0.05) higher cellular uptake than pure astaxanthin powder.
    Matched MeSH terms: Antioxidants/chemistry*
  5. Antioxidant properties of phenolic Schiff bases: structure-activity relationship and mechanism of action
    Anouar el H, Raweh S, Bayach I, Taha M, Baharudin MS, Di Meo F, et al.
    J Comput Aided Mol Des, 2013 Nov;27(11):951-64.
    PMID: 24243063 DOI: 10.1007/s10822-013-9692-0
    Phenolic Schiff bases are known for their diverse biological activities and ability to scavenge free radicals. To elucidate (1) the structure-antioxidant activity relationship of a series of thirty synthetic derivatives of 2-methoxybezohydrazide phenolic Schiff bases and (2) to determine the major mechanism involved in free radical scavenging, we used density functional theory calculations (B3P86/6-31+(d,p)) within polarizable continuum model. The results showed the importance of the bond dissociation enthalpies (BDEs) related to the first and second (BDEd) hydrogen atom transfer (intrinsic parameters) for rationalizing the antioxidant activity. In addition to the number of OH groups, the presence of a bromine substituent plays an interesting role in modulating the antioxidant activity. Theoretical thermodynamic and kinetic studies demonstrated that the free radical scavenging by these Schiff bases mainly proceeds through proton-coupled electron transfer rather than sequential proton loss electron transfer, the latter mechanism being only feasible at relatively high pH.
    Matched MeSH terms: Antioxidants/chemistry*
  6. Comparative phytochemical composition, oleuropein quantification, antioxidant and cytotoxic properties of Olea europaea L. leaves
    Anwar S, Saleem H, Khurshid U, Ansari SY, Alghamdi S, Al-Khulaidi AWA, et al.
    Nat Prod Res, 2023 Mar;37(6):1023-1029.
    PMID: 35815778 DOI: 10.1080/14786419.2022.2097230
    In the present research, oleuropein (OLE) contents from two Saudi Arabian wild olive trees (Olea europaea L.) leaves (O1 and O2), were collected from two nearby geographical sites differing in altitudes, and were determined via UHPLC-MS analysis. Moreover, total bioactive contents, antioxidant, and cytotoxicity (against MCF-7 and MDA-MB-231 cells) potential were also evaluated. The sample (O2) was found to contain significantly (p 
    Matched MeSH terms: Antioxidants/chemistry
  7. Fulltext Colostrum supplementation protects against exercise-induced oxidative stress in skeletal muscle in mice
    Appukutty M, Radhakrishnan AK, Ramasamy K, Ramasamy R, Abdul Majeed AB, Noor MI, et al.
    BMC Res Notes, 2012;5:649.
    PMID: 23173926 DOI: 10.1186/1756-0500-5-649
    This study examined the effects of bovine colostrum on exercise -induced modulation of antioxidant parameters in skeletal muscle in mice. Adult male BALB/c mice were randomly divided into four groups (control, colostrum alone, exercise and exercise with colostrum) and each group had three subgroups (day 0, 21 and 42). Colostrum groups of mice were given a daily oral supplement of 50 mg/kg body weight of bovine colostrum and the exercise group of mice were made to exercise on the treadmill for 30 minutes per day. Total antioxidants, lipid hydroperoxides, xanthine oxidase and super oxide dismutase level was assayed from the homogenate of hind limb skeletal muscle.
    Matched MeSH terms: Antioxidants/chemistry
  8. PASS-assisted design, synthesis and antioxidant evaluation of new butylated hydroxytoluene derivatives
    Ariffin A, Rahman NA, Yehye WA, Alhadi AA, Kadir FA
    Eur J Med Chem, 2014 Nov 24;87:564-77.
    PMID: 25299680 DOI: 10.1016/j.ejmech.2014.10.001
    New multipotent antioxidants (MPAOs), namely 1,3,4-thiadiazoles and 1,2,4-triazoles bearing the well-known free radical scavenger butylated hydroxytoluene (BHT), were designed and synthesized using an acid-(base-) catalyzed intramolecular dehydrative cyclization reaction of the corresponding 1-acylthiosemicarbazides. The structure-activity relationship (SAR) of the designed antioxidants was performed along with the prediction of activity spectra for substances (PASS) training set. Experimental studies based on antioxidant activity using DPPH and lipid peroxidation assays verified the predictions obtained by the PASS-assisted design strategy. Compounds 4a-b, 5a-b and 6a-b showed an inhibition of stable DPPH free radicals at a 10(-4) M more than the well-known standard antioxidant BHT. Compounds with p-methoxy substituents (4b, 5b and 6b) were more active than o-methoxy substituents (4a, 5a and 6a). With an IC50 of 2.85 ± 1.09 μM, compound 6b exhibited the most promising in vitro inhibition of lipid peroxidation, inhibiting Fe(2+)-induced lipid peroxidation of essential oils derived from the egg yolk-based lipid-rich medium by 86.4%. The parameters for the drug-likeness of these BHT derivatives were also evaluated according to Lipinski's 'rule-of-five'. All of the BHT derivatives were found to violate one of Lipinski's parameters (Log P ≥ 5) even though they have been found to be soluble in protic solvents. The predictive TPSA and %ABS data allow for the conclusion that these compounds could have a good capacity for penetrating cell membranes. Therefore, these novel MPAOs containing lipophilic and hydrophilic groups can be proposed as potential antioxidants for tackling oxidative stress and lipid peroxidation processes.
    Matched MeSH terms: Antioxidants/chemistry
  9. An overview of structure-activity relationship studies of curcumin analogs as antioxidant and anti-inflammatory agents
    Arshad L, Haque MA, Abbas Bukhari SN, Jantan I
    Future Med Chem, 2017 04;9(6):605-626.
    PMID: 28394628 DOI: 10.4155/fmc-2016-0223
    Curcumin, extracted mainly from Curcuma longa rhizomes, has been reported to possess potent anti-inflammatory and anti-oxidant activities. Although safe at higher doses and exhibiting multiple biological activities, curcumin still has the problem of poor bioavailability which has been an attractive area of research over the last few years. A number of efforts have been made by modifying structural features of curcumin. This review highlights the structurally modified and more stable newly synthesized curcumin analogs that have been screened against antioxidant and anti-inflammatory activities. Also the structure-activity relationship to gain insight into future guidelines for scheming new compounds has been discussed, and further these analogs being more stable may serve as promising agents for use in different pathological conditions.
    Matched MeSH terms: Antioxidants/chemistry
  10. Role of Antioxidants and Natural Products in Inflammation
    Arulselvan P, Fard MT, Tan WS, Gothai S, Fakurazi S, Norhaizan ME, et al.
    Oxid Med Cell Longev, 2016;2016:5276130.
    PMID: 27803762
    Inflammation is a comprehensive array of physiological response to a foreign organism, including human pathogens, dust particles, and viruses. Inflammations are mainly divided into acute and chronic inflammation depending on various inflammatory processes and cellular mechanisms. Recent investigations have clarified that inflammation is a major factor for the progression of various chronic diseases/disorders, including diabetes, cancer, cardiovascular diseases, eye disorders, arthritis, obesity, autoimmune diseases, and inflammatory bowel disease. Free radical productions from different biological and environmental sources are due to an imbalance of natural antioxidants which further leads to various inflammatory associated diseases. In this review article, we have outlined the inflammatory process and its cellular mechanisms involved in the progression of various chronic modern human diseases. In addition, we have discussed the role of free radicals-induced tissue damage, antioxidant defence, and molecular mechanisms in chronic inflammatory diseases/disorders. The systematic knowledge regarding the role of inflammation and its associated adverse effects can provide a clear understanding in the development of innovative therapeutic targets from natural sources that are intended for suppression of various chronic inflammations associated diseases.
    Matched MeSH terms: Antioxidants/chemistry
  11. Manganese disulfide-silicon dioxide nano-material: Synthesis, characterization, photocatalytic, antioxidant and antimicrobial studies
    Ashraf MA, Peng WX, Fakhri A, Hosseini M, Kamyab H, Chelliapan S
    J. Photochem. Photobiol. B, Biol., 2019 Sep;198:111579.
    PMID: 31401316 DOI: 10.1016/j.jphotobiol.2019.111579
    The sol-gel/ultrasonically rout produced the novel MnS2-SiO2 nano-hetero-photocatalysts with the various ratio of MnS2. Prepared nano-catalyst were investigated in the photo-degradation of methylene blue under UV light illumination. Structural and optical attributes of as-prepared nano-catalysts were evaluated by X-ray diffraction and photoelectron spectroscopy. The morphological were studied by scanning electron microscopy-EDS, and dynamic light scattering. The diffuse reflectance spectroscopy was applied to examine the band gap energy. The Eg values of SiO2, MnS2-SiO2-0, MnS2-SiO2-1, and MnS2-SiO2-2 nanocomposites are 6.51, 3.85, 3.17, and 2.67 eV, respectively. The particle size of the SiO2 and MnS2-SiO2-1 nanocomposites were 100.0, and 65.0 nm, respectively. The crystallite size values of MnS2-SiO2-1 were 52.21 nm, and 2.9 eV, respectively. MnS2-SiO2 nano-photocatalyst was recognized as the optimum sample by degrading 96.1% of methylene blue from water. Moreover, the influence of pH of the solution, and contact time as decisive factors on the photo-degradation activity were investigated in this project. The optimum data for pH and time were found 9 and 60 min, respectively. The photo-degradation capacity of MnS2-SiO2-2 is improved (96.1%) due to the low band gap was found from UV-vis DRS. The antimicrobial data of MnS2-SiO2 were studied and demonstrated that the MnS2-SiO2 has fungicidal and bactericidal attributes.
    Matched MeSH terms: Antioxidants/chemistry*
  12. Improving fried burger quality and modulating acrylamide formation by active coating containing Rosa canina L. extract nanoemulsions
    Ashrafi A, Ahari H, Asadi G, Nafchi AM
    J Food Sci, 2024 Apr;89(4):2158-2173.
    PMID: 38488727 DOI: 10.1111/1750-3841.17019
    During the frying of foods, undesirable reactions such as protein denaturation, acrylamide formation, and so on occur in the product, which has confirmed carcinogenic effects. The use of antioxidants has been proposed as an effective solution to reduce the formation of these compounds during the process. The current study aimed to assess the impact of an edible coating holding within chia seed gum (CSG) and Rosa canina L. extract (RCE) nanoemulsions on the physicochemical properties, oil uptake, acrylamide formation, 5-hydroxymethyl-2-furfural (HMF) content, and sensory characteristics of beef-turkey burgers. The RCE-loaded nanoemulsions were prepared using the ultrasonic homogenization method, and different concentrations (i.e., 10%, 20%, and 40% w/w) were added to the CSG solutions; these active coatings were used to cover the burgers. CSG-based coatings, especially coatings containing the highest concentration of nanoemulsions (40%), caused a significant decrease in the oil uptake and moisture retention, acrylamide content, and HMF content of fried burgers. The texture of coated burgers was softer than that of uncoated samples; they also had a higher color brightness and a lower browning index. Field emission scanning electron microscopy analysis showed that RCE concentration less than 40% should be used in CSG coatings because it will cause minor cracks, which is an obvious possibility of failure of coating performance. Coating significantly (4-10 times) increased the antioxidant activity of burgers compared to the control. In conclusion, it is suggested to use the active coating produced in this study to improve fried burger quality and modulate acrylamide formation.
    Matched MeSH terms: Antioxidants/chemistry
  13. Antioxidant versus anti-diabetic properties of leaves from Vernonia amygdalina Del. growing in Malaysia
    Atangwho IJ, Egbung GE, Ahmad M, Yam MF, Asmawi MZ
    Food Chem, 2013 Dec 15;141(4):3428-34.
    PMID: 23993503 DOI: 10.1016/j.foodchem.2013.06.047
    The antioxidant and anti-diabetic properties of the sequential extracts of Vernonia amygdalina based on the chemical composition of the most effective anti-diabetic extract were studied. Using DPPH and ABTS radical scavenging as well as FRAP assays, the extracts showed a consistent dose-dependent trend of potent antioxidant activity in the following solvents: water extract>methanol extract>chloroform extract>and petroleum ether extracts. In the oral glucose tolerance test, the chloroform extract exerted the highest response (33.3%), similar to metformin (27.2%), after 2h compared to the control (50.8%, P<0.05). After a 14-day administration in diabetic rats, the chloroform extract recorded the highest blood (23.5%) and serum (21.4%) glucose-lowering effects (P<0.05). GC-MS analysis of the chloroform extract revealed high levels of linoleic acid (4.72%), α-linolenic acid (10.8%) and phytols (12.0%), as well as other compounds.
    Matched MeSH terms: Antioxidants/chemistry
  14. Fulltext Synthesis, crystal structure, DFT studies and evaluation of the antioxidant activity of 3,4-dimethoxybenzenamine schiff bases
    Aziz AN, Taha M, Ismail NH, Anouar el H, Yousuf S, Jamil W, et al.
    Molecules, 2014 Jun 19;19(6):8414-33.
    PMID: 24950444 DOI: 10.3390/molecules19068414
    Schiff bases of 3,4-dimethoxybenzenamine 1-25 were synthesized and evaluated for their antioxidant activity. All the synthesized compounds were characterized by various spectroscopic techniques. In addition, the characterizations of compounds 13, 15 and 16 were supported by crystal X-ray determinations and their geometrical parameters were compared with theoretical DFT calculations at the B3LYP level of theory. Furthermore, the X-ray crystal data of two non-crystalline compounds 8 and 18 were theoretically calculated and compared with the practical values of compounds 13, 15, 16 and found a good agreement. The compounds showed good DPPH scavenging activity ranging from 10.12 to 84.34 μM where compounds 1-4 and 6 showed stronger activity than the standard n-propyl gallate. For the superoxide anion radical assay, compounds 1-3 showed better activity than the standard.
    Matched MeSH terms: Antioxidants/chemistry*
  15. Fulltext Green Microwave-Assisted Combustion Synthesis of Zinc Oxide Nanoparticles with Citrullus colocynthis (L.) Schrad: Characterization and Biomedical Applications
    Azizi S, Mohamad R, Mahdavi Shahri M
    Molecules, 2017 Feb 16;22(2).
    PMID: 28212344 DOI: 10.3390/molecules22020301
    In this paper, a green microwave-assisted combustion approach to synthesize ZnO-NPs using zinc nitrate and Citrullus colocynthis (L.) Schrad (fruit, seed and pulp) extracts as bio-fuels is reported. The structure, optical, and colloidal properties of the synthesized ZnO-NP samples were studied. Results illustrate that the morphology and particle size of the ZnO samples are different and depend on the bio-fuel. The XRD results revealed that hexagonal wurtzite ZnO-NPs with mean particle size of 27-85 nm were produced by different bio-fuels. The optical band gap was increased from 3.25 to 3.40 eV with the decreasing of particle size. FTIR results showed some differences in the surface structures of the as-synthesized ZnO-NP samples. This led to differences in the zeta potential, hydrodynamic size, and more significantly, antioxidant activity through scavenging of 1, 1-Diphenyl-2-picrylhydrazyl (DPPH) free radicals. In in vitro cytotoxicity studies on 3T3 cells, a dose dependent toxicity with non-toxic effect of concentration below 0.26 mg/mL was shown for ZnO-NP samples. Furthermore, the as-synthesized ZnO-NPs inhibited the growth of medically significant pathogenic gram-positive (Bacillus subtilis and Methicillin-resistant Staphylococcus aurous) and gram-negative (Peseudomonas aeruginosa and Escherichia coli) bacteria. This study provides a simple, green and efficient approach to produce ZnO nanoparticles for various applications.
    Matched MeSH terms: Antioxidants/chemistry
  16. Fulltext Tualang Honey: A Decade of Neurological Research
    Azman KF, Aziz CBA, Zakaria R, Ahmad AH, Shafin N, Ismail CAN
    Molecules, 2021 Sep 06;26(17).
    PMID: 34500857 DOI: 10.3390/molecules26175424
    Tualang honey has been shown to protect against neurodegeneration, leading to improved memory/learning as well as mood. In addition, studies have also demonstrated its anti-inflammatory and antioxidant properties. However, a substantial part of this research lacks systematization, and there seems to be a tendency to start anew with every study. This review presents a decade of research on Tualang honey with a particular interest in the underlying mechanisms related to its effects on the central nervous system. A total of 28 original articles published between 2011 and 2020 addressing the central nervous system (CNS) effects of Tualang honey were analysed. We identified five main categories, namely nootropic, antinociceptive, stress-relieving, antidepressant, and anxiolytic effects of Tualang honey, and proposed the underlying mechanisms. The findings from this review may potentially be beneficial towards developing new therapeutic roles for Tualang honey and help in determining how best to benefit from this brain supplement.
    Matched MeSH terms: Antioxidants/chemistry*
  17. Use of lyophilised and powdered Gentiana lutea root in fresh beef patties stored under different atmospheres
    Azman NA, Gordon MH, Skowyra M, Segovia F, Almajano MP
    J Sci Food Agric, 2015 Jul;95(9):1804-11.
    PMID: 25139796 DOI: 10.1002/jsfa.6878
    Gentiana lutea root is a medicinal herb that contains many active compounds which contribute to physiological effects, and it has recently attracted much attention as a natural source of antioxidants. The aim of this study was to evaluate the effects on the colour, pH, microbial activities, sensory quality and resistance to lipid oxidation (through the thiobarbituric acid method) during storage of beef patties containing different concentrations of G. lutea. Fresh beef patties were formulated with 0-5 g kg(-1) of G. lutea and 0 or 0.5 g kg(-1) of ascorbic acid and packed in two different atmospheres, Modified Atmosphere 1 (MAP1) and Modified Atmosphere 2 (MAP2), and stored at 4 ± 1 °C for 10 days. MAP1 contained 20:80 (v/v) O2:CO2 and MAP2 contained 80:20 (v/v) O2:CO2.
    Matched MeSH terms: Antioxidants/chemistry*
  18. Fulltext Etlingera elatior-Mediated Synthesis of Gold Nanoparticles and Their Application as Electrochemical Current Enhancer
    Azri FA, Selamat J, Sukor R, Yusof NA, Ahmad Raston NH, Nordin N, et al.
    Molecules, 2019 Aug 29;24(17).
    PMID: 31470528 DOI: 10.3390/molecules24173141
    This work presents a simple green synthesis of gold nanoparticles (AuNPs) by using an aqueous extract of Etlingera elatior (torch ginger). The metabolites present in E. elatior, including sugars, proteins, polyphenols, and flavonoids, were known to play important roles in reducing metal ions and supporting the subsequent stability of nanoparticles. The present work aimed to investigate the ability of the E. elatior extract to synthesise AuNPs via the reduction of gold (III) chloride hydrate and characterise the properties of the nanoparticles produced. The antioxidant properties of the E. elatior extract were evaluated by analysing the total phenolic and total flavonoid contents. To ascertain the formation of AuNPs, the synthesised particles were characterised using the ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray (EDX) microscopy, and dynamic light scattering (DLS) measurement. The properties of the green synthesised AuNPs were shown to be comparable to the AuNPs produced using a conventional reducing agent, sodium citrate. The UV-Vis measured the surface plasmon resonance of the AuNPs, and a band centered at 529 nm was obtained. The FTIR results proved that the extract contained the O-H functional group that is responsible for capping the nanoparticles. The HRTEM images showed that the green synthesized AuNPs were of various shapes and the average of the nanoparticles' hydrodynamic diameter was 31.5 ± 0.5 nm. Meanwhile, the zeta potential of -32.0 ± 0.4 mV indicates the high stability and negative charge of the AuNPs. We further successfully demonstrated that using the green synthesised AuNPs as the nanocomposite to modify the working surface of screen-printed carbon electrode (SPCE/Cs/AuNPs) enhanced the rate of electron transfer and provided a sensitive platform for the detection of Cu(II) ions.
    Matched MeSH terms: Antioxidants/chemistry
  19. Antioxidant and anti-inflammatory activities contribute to the prophylactic effect of semi-purified fractions obtained from the crude methanol extract of Muntingia calabura leaves against gastric ulceration in rats
    Balan T, Sani MH, Mumtaz Ahmad SH, Suppaiah V, Mohtarrudin N, Zakaria ZA
    J Ethnopharmacol, 2015 Apr 22;164:1-15.
    PMID: 25540923 DOI: 10.1016/j.jep.2014.12.017
    In traditional medicine, the leaves, flowers, barks and roots of Muntingia calabura L. (Muntingiaceae) have been employed as a treatment for various ailments including dyspepsia and to relieve pain caused by gastritis and peptic ulcer disease. The methanolic extract of Muntingia calabura leaves (MEMC) has been proven in the previous study to possess significant antiulcer activity. In this study, we attempted to determine the prophylactic effect of the fractions obtained from MEMC against ethanol-induced gastric lesion in rats and the involvement of antioxidants and anti-inflammatory mediators.
    Matched MeSH terms: Antioxidants/chemistry
  20. Fulltext Phytoantioxidant Functionalized Nanoparticles: A Green Approach to Combat Nanoparticle-Induced Oxidative Stress
    Balkrishna A, Kumar A, Arya V, Rohela A, Verma R, Nepovimova E, et al.
    Oxid Med Cell Longev, 2021;2021:3155962.
    PMID: 34737844 DOI: 10.1155/2021/3155962
    Nanotechnology is gaining significant attention, with numerous biomedical applications. Silver in wound dressings, copper oxide and silver in antibacterial preparations, and zinc oxide nanoparticles as a food and cosmetic ingredient are common examples. However, adverse effects of nanoparticles in humans and the environment from extended exposure at varied concentrations have yet to be established. One of the drawbacks of employing nanoparticles is their tendency to cause oxidative stress, a significant public health concern with life-threatening consequences. Cardiovascular, renal, and respiratory problems and diabetes are among the oxidative stress-related disorders. In this context, phytoantioxidant functionalized nanoparticles could be a novel and effective alternative. In addition to performing their intended function, they can protect against oxidative damage. This review was designed by searching through various websites, books, and articles found in PubMed, Science Direct, and Google Scholar. To begin with, oxidative stress, its related diseases, and the mechanistic basis of oxidative damage caused by nanoparticles are discussed. One of the main mechanisms of action of nanoparticles was unearthed to be oxidative stress, which limits their use in humans. Secondly, the role of phytoantioxidant functionalized nanoparticles in oxidative damage prevention is critically discussed. The parameters for the characterization of nanoparticles were also discussed. The majority of silver, gold, iron, zinc oxide, and copper nanoparticles produced utilizing various plant extracts were active free radical scavengers. This potential is linked to several surface fabricated phytoconstituents, such as flavonoids and phenols. These phytoantioxidant functionalized nanoparticles could be a better alternative to nanoparticles prepared by other existing approaches.
    Matched MeSH terms: Antioxidants/chemistry
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