A new colorimetric technique for the estimation of vitamin C using Folin phenol reagent.

Department of Biochemistry, Panjab University, Chandigarh-160 014, India
Analytical Biochemistry (Impact Factor: 2.58). 12/1982; 127(1):178-82. DOI: 10.1016/0003-2697(82)90162-2
Source: PubMed

ABSTRACT A new colorimetric technique for the estimation of ascorbic acid by using Folin phenol reagent has been developed. The absorption maximum of the color developed by the interaction of ascorbic acid with Folin reagent is 760 nm. The technique obeys the Beer-Lambert law up to a concentration of 45 μg ascorbic acid as shown by the standard curve. The color developed has been found to be stable up to 18 h. Recovery experiments showed that the technique is almost 100% efficient. The development of the color is not obstructed by glucose, glutathione, bovine serum albumin, urea, cysteine, adenine, guanine, cytosine, uracil, sulfosalicylic acid, thymol, or oxyhemoglobin, which are compounds suspected of interfering in routine analysis. The technique is simple, quick, and efficient and can be employed for the estimation of ascorbic acid in a wide variety of biological materials.

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    ABSTRACT: Background: Tuberculosis (TB) still remains a major cause of morbidity and mortality worldwide. In Nigeria, there is little information on antioxidant status of TB patients. In this study, effects of oxidative stress markers and vitamins C and E were investigated in pulmonary TB patients at-tending a health care facility in Nigeria. Methods: Sputum specimens were processed for acid-fast bacilli (AFB) while rifampicin resistance was determined by GeneXpert/Rif assay. Patients were screened for HIV after adequate counselling. Assays for hydrogen peroxide (H 2 O 2), malondialde-hyde (MDA), protein carbonyl (PC), myeloperoxidase (MPx), xanthine oxidase (XO), catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH), glutathione S-transferase (GST), glu-tathione peroxidase (GPx), α-tocopherol and ascorbic acid were estimated using standard me-thods. Results: Of the 83 recruited subjects, 29 (34.9%) were AFB negative, 30 (36.1%) were AFB positive while 24 (29.0%) were positive for rifampicin resistance. Overall, HIV prevalence was 6.0% while higher rate of 16.7% was found among the rifampicin resistant subjects. Plasma con-centrations of H2O2, MDA and PC and also MPx and XO activities were significantly higher among rifampicin resistant subjects compared with AFB positive and AFB negative groups (P < 0.05). Plasma concentration of GSH and the activities of SOD, GST and GPX were significantly reduced in rifampicin resistant subjects compared with the 2 other groups (P < 0.05). The plasma activity of CAT was similar between rifampicin resistant and AFB positive subjects but significantly lower when compared with AFB negative group. Rifampicin resistant subjects had significantly lower concentrations of α-tocopherol and ascorbic acid compared with 2 other groups (P < 0.05). Con-clusion: This study revealed that resistance of TB patients to rifampicin may be due to induction of oxidative stress. Administration of vitamins C and E may be beneficial by reducing the severity of the disease.
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    ABSTRACT: Aim Aquaporin-4(AQP4) expression in brain with relation to edema formation following focal cerebral ischemia was investigated. Studies have shown that brain edema is one of the significant factors in worsening stroke outcomes. While many mechanisms may aggravate brain injury, one such potential system may involve AQP4 up regulation in stroke patients that could result in increased edema formation. Post administration of melatonin following ischemic stroke reduces AQP4 mediated brain edema and confer neuroprotection. Materials and Methods An in-silico approach was undertaken to confirm effective melatonin-AQP4 binding. Rats were treated with 5mg/kg, i.p. melatonin OR placebo at 30 min prior, 60 min post and 120 min post 60 minutes of MCAO followed by 24 hour reperfusion. Rats were evaluated for battery of neurological and motor function tests just before sacrifice. Brains were harvested for infarct size estimation, water content measurement, biochemical analysis, apoptosis study and western blot experiments. Key findings Melatonin at sixty minutes post ischemia rendered neuroprotection as evident by reduction in cerebral infarct volume, improvement in motor and neurological deficit and reduction in brain edema. Furthermore, ischemia induced surge in levels of nitrite and MDA were also found to be significantly reduced in ischemic brain regions in treated animals. Melatonin potentiated intrinsic antioxidant status, inhibited acid mediated rise in intracellular calcium levels, decreased apoptotic cell death and also markedly inhibited protein kinase C influenced AQP4 expression in the cerebral cortex and dorsal striatum. Significance Melatonin confer neuroprotection by Protein Kinase C mediated AQP4 inhibition in ischemic stroke.
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    ABSTRACT: Background: COPD may develop due to variation in the functioning of antioxidants along with smoking and environmental factors in genetically susceptible individuals. Since there are different views about the antioxidants responsible for detoxifying xenobiotic compound in the human body whose functional variation may lead to obstructive disease, this associative study has been taken up between GST gene polymorphism and COPD in populations exposed to coal dusts. Methods: Genotypes of the 70 COPD patients and 85 non COPD patients were determined by PCR based methods followed by multiplex PCR of GSTT1 and GSTM1 genes taking albumin gene as a control. Suspended particulate analyses were determined through the Respirable Dust sampler along with the FTIR analysis of the dust samples from the glass microfiber filters. Results: Dust sampling analysis reveals higher level of respirable suspended particulate matter, non respirable particulate matter, SO2 and NO2 present in air of the study site. FTIR analysis also suggests a higher concentration of organic silicone and aliphatic C-F compounds present in air of the study site and when spirometry was done, low lung function was observed among most of the subjects. GSTM1 null type was significantly associated with low lung function in smoker groups and the presence of at least one active allele (either GSTM1/GSTT1) seemed to have a protective role in the development of COPD. Conclusions: GSTM1 (null genotype) appeared to be a risk factor for lower lung function in smokers living in the vicinity of coal mines. Apart from polluted environment and genetic susceptibility, mixed coal dust exposure rich in organic silicone and aliphatic C-F compounds also appears to be a factor for the low lung function.
    PLoS ONE 05/2014; May 2014 | Volume 9 | Issue 5 | e96739(5):e96739. · 3.73 Impact Factor


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