Author
Muhammad Nadeem Asghar
Bio: Muhammad Nadeem Asghar is an academic researcher from Government College University. The author has contributed to research in topics: Ring (chemistry) & ABTS. The author has an hindex of 5, co-authored 13 publications receiving 88 citations.
Papers
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Journal Article•
TL;DR: An improved decolorization method for measuring the antioxidant activity of food samples using N,N-dimethyl-p-phenylenediamine (DMPD) is developed.
Abstract: An improved decolorization method for measuring the antioxidant activity of food samples using N,N-dimethyl-p-phenylenediamine (DMPD) is developed. DMPD radical cation (DMPD° + ) is generated through a reaction between DMPD and potassium persulfate and is subsequently reduced in the presence of hydrogen-donating antioxidants. This assay has a clear edge over the previous DMPD assay (the DMPD/FeCl 3 assay) for the determination of antioxidant activity on a number of counts. The chemistry involves the generation of a more stable DMPD radical mono-cation by a reaction with potassium persulfate. The DMPD radical cation generator does not involve Fe(II) ions, which through Fenton's Reaction could cause negative deviation in the antioxidant activity of food extracts. The assay can equally be applied to the determination of antioxidant capacity of both hydrophilic and lipophilic antioxidants. The experimental procedure is rapid, inexpensive and ensures sensitivity along with reproducibility in the measurement of antioxidant activity of hydrophilic and lipophilic compounds and thus has a promising aspect of use in screening large number of fruit samples. The effectiveness of new DMPD decolorization assay was verified by evaluating the antioxidant capacity of different fruit samples.
22 citations
TL;DR: The results obtained in the present study indicate that both Abutilon species are potential sources of natural antioxidants.
Abstract: Abutilon indicum L. (Malvaceae) and Abutilon muticum DC. (Malvaceae) are traditional medicinal herbs used for analgesic, anthelmintic, hepatoprotective, and hypoglycemic properties. These effects may be correlated with the presence of antioxidant compounds. Extracts in organic solvents from the aerial parts and roots of both species were prepared and evaluated for their total antioxidant capacity (TAC), total phenolic content, and total flavonoid content. The Trolox equivalent antioxidant capacity (TEAC) of all the extracts of both plants was found, employing ABTS and FRAP assays. TEAC values ranged from 3.019 to 10.5 μM for n-hexane and butanol fractions of Abutilon indicum and from 2.247 to 14.208 μM for n-hexane and butanol fractions of Abutilon muticum, respectively, using the ABTS assay. The FRAP assay showed reducing powers of the fractions in the order of butanol > ethyl acetate > chloroform > n-hexane and butanol > chloroform > hexane > ethyl acetate for Abutilon indicum and Abutilon muticum, resp...
17 citations
TL;DR: In this article, a simple, fast, and accurate highperformance liquid chromatography (HPLC) method was developed to determine latanoprost in pharmaceutical formulations, where the drug was chromatographed on a C18 column and monitored at a wavelength of 210nm using a mixture of acetonitrile and 0.05m potassium phosphate buffer pH 3.0 (70:30, (v/v).
Abstract: A simple, fast, and accurate high‐performance liquid chromatography (HPLC) method was developed to determine latanoprost in pharmaceutical formulations. The drug was chromatographed on a C18 column. Eluents were monitored at a wavelength of 210 nm using a mixture of acetonitrile and 0.05 M potassium phosphate buffer pH 3.0 (70:30, (v/v). A linear response (r>0.9998) was observed in the range of 10.0–90.0 µg mL−1. The method showed good recoveries (average 100.4%) and the relative standard deviations intra‐ and inter‐day were ≤1.0%. The method can be used for quality control assay of latanoprost in raw materials as well as in pharmaceutical formulations.
12 citations
Journal Article•
TL;DR: In this article, an improved 2,2'-Azinobis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) radical cation decolorization method was proposed for the measurement of antioxidant activity of human plasma and herbal extracts.
Abstract: 2,2'-Azinobis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) radical cation decolorization assay has been applied under different pH conditions for the determination of trolox equivalent antioxidant capacity (TEAC) of biological and food samples. Due to innate nature of ABTS radical cation, it is unstable at physiological pH. Further, its sensitivity is also lost at acidic pH. No single method has yet claimed to cover both drawbacks of the ABTS procedure. The present investigation was aimed at developing an improved ABTS decolorization method for the measurement of antioxidant activity of human plasma and herbal extracts with greater stability and sufficient sensitivity. A relatively stable ABTS radical cation was generated through a reaction between ABTS and potassium persulfate in the presence of sodium acetate buffer at pH 6.5 (20 mM). The electron or hydrogen atom transfer from antioxidative components of plasma or herbal extracts reduced the radical cation. Standard antioxidants like trolox, butylated hydroxyanisol (BHA), butylated hydroxytoluene (BHT) and ascorbic acid demonstrated stable end-point readings showing a promising aspect of determination of total antioxidant activity (TAA) of all the other samples with reference to these indicators. The modified assay proved to be highly reproducible. TEAC values for plasma samples ranged between 1.410-2.025 mM with mean percent relative standard deviation (% RSD) 1.64 and between 1.72-1.98 with mean % RSD 1.27 for older and modified ABTS assays, respectively. The efficacy of the assay was ascertained further by determining antioxidant activity of organic and aqueous extracts of Cuscuta reflexa and Terminalia arjuna.
11 citations
TL;DR: In this article, the authors investigated the threats to insect biodiversity associated with rice crop agroecosystem by excessive and increasing use of agrochemicals (78.7%) and rice straw burning (68%) along with animal grazing were explored as major threats.
Abstract: During a survey and through face to face interviews of rice farmers, their attitudes and substandard farming practices were investigated as threats to insect biodiversity associated with rice crop agroecosystem. Excessive and increasing use of agrochemicals (78.7%) and rice straw burning (68%) along with animal grazing were explored as major threats. Rational use of agrochemicals and legislation about bans of rice straw burning and cattle grazing in harvested rice fields were proposed.
Key words: Insect biodiversity, rice farmers, straw burning, animal grazing.
11 citations
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01 Jan 1976
TL;DR: A positive temperature coefficient is the term which has been used to indicate that an increase in solubility occurs as the temperature is raised, whereas a negative coefficient indicates a decrease in Solubility with rise in temperature.
Abstract: A positive temperature coefficient is the term which has been used to indicate that an increase in solubility occurs as the temperature is raised, whereas a negative coefficient indicates a decrease in solubility with rise in temperature.
1,573 citations
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TL;DR: The Wealth of India: A Dictionary of Indian Raw Materials and Industrial Products as mentioned in this paper is a dictionary of the economic products of India that was published during the years 1889-99 by the Government of India.
Abstract: IT may occasion some surprise to those men of science who are ill-acquainted with India, and who so frequently express the view that Governments are unappreciative of the importance of science to learn that as far back as 1886 the Government of India arranged for Dr. George (later Sir George) Watt, professor of botany in the Presidency College, Calcutta, to prepare a "Dictionary of the Economic Products of India". The six volumes of this standard work were published during the years 1889-99. In 1908 Sir George Watt published a condensed version, "The Commercial Products of India". Whatever the defects of these 'dictionaries', they have been of inestimable value to all interested in Indian natural products. The Wealth of India A Dictionary of Indian Raw Materials and Industrial Products. Raw Materials, Vol. 1. Pp. xxvii+254+39 plates. 15 rupees ; 24s. Industrial Products, Part 1. Pp. xii+182+8 plates. 8 rupees ; 12s. (New Delhi : Council of Scientific and Industrial Research, 1948.)
694 citations
TL;DR: Assessment of the total antioxidant capacity of some commercial fruit juices, spectrophotometrically and by the biamperometric method, using the redox couple DPPH· (2,2-diphenyl-1-picrylhydrazyl/DPPH) and Trolox®, in good agreement.
Abstract: The aim of this paper was to assess the total antioxidant capacity of some commercial fruit juices (namely citrus), spectrophotometrically and by the biamperometric method, using the redox couple DPPH· (2,2-diphenyl-1-picrylhydrazyl)/DPPH (2,2-diphenyl-1-picrylhydrazine). Trolox® was chosen as a standard antioxidant. In the case of the spectrophometric method, the absorbance decrease of the DPPH· solution was followed. For the biamperometric method, the influence of some parameters like the potential diference, ΔE, DPPH· concentration, and Trolox® concentration was investigated. The calibration graph obtained for Trolox® presents linearity between 5 and 30 µM, (y = 0.059 x + 0.0564, where y represents the value of current intensity, expressed as μA and x the value of Trolox® concentration, expressed as μM; r2 = 0.9944). The R.S.D. value for the biamperometric method was 1.29% (n = 10, c = 15 μM Trolox®). In the case of the spectrophotometric method, the calibration graph obtained for Trolox® presents linearity between 0.01 and 0.125 mM (y = -9.5789 x+1.4533, where y represents the value of absorbance and x, the value of Trolox® concentration, expressed as mM; r2 = 0.9963). The R.S.D. value for the spectrophotometric method was 2.05%. Both methods were applied to total antioxidant activity determination in real samples (natural juices and soft drinks) and the results were in good agreement.
138 citations
TL;DR: The synthesised complex structures were determined by UV-vis spectrophotometry, infrared spectroscopy, thermogravimetry and differential thermal analysis techniques, and the structure of the compounds was elucidated on the basis of obtained results.
124 citations