Natural antioxidant activity of commonly consumed plant foods in India: effect of domestic processing.

Phytochemicals protect against oxidative stress which in turn helps in maintaining the balance between oxidants and antioxidants. In recent times natural antioxidants are gaining considerable interest among nutritionists, food manufacturers, and consumers because of their perceived safety, potential therapeutic value, and long shelf life. Plant foods are known to protect against degenerative diseases and ageing due to their antioxidant activity (AOA) attributed to their high polyphenolic content (PC). Data on AOA and PC of Indian plant foods is scanty. Therefore we have determined the antioxidant activity in 107 commonly consumed Indian plant foods and assessed their relation to their PC. Antioxidant activity is presented as the range of values for each of the food groups. The foods studied had good amounts of PC and AOA although they belonged to different food groups. Interestingly, significant correlation was observed between AOA (DPPH and FRAP) and PC in most of the foods, corroborating the literature that polyphenols are potent antioxidants and that they may be important contributors to the AOA of the plant foods. We have also observed that common domestic methods of processing may not affect the PC and AOA of the foods studied in general. To the best of our knowledge, these are the first results of the kind in commonly consumed Indian plant foods.

Antioxidant activity of commonly consumed cereals, millets, pulses and legumes in India.

Plant foods are important due to their antioxidant activity (AOA) attributed to the phenolics which are known to protect organisms against harmful effects of oxygen radicals. However, information on antioxidant activity of Indian plant foods is scanty. Therefore, the present study evaluated the AOA of cereals, millets, pulses and legumes, commonly consumed in India and assessed the relationship with their total phenolic content (TPC). AOA was assessed by DPPH (2,2-Diphenyl-1-picryl hydrazyl) radical scavenging assay, ferric reducing antioxidant power (FRAP) assay and reducing power. DPPH scavenging activity ranged from 0.24 and 1.73 mg/g, whereas FRAP ranged from 16.21 to 471.71 micromoles/g. Finger millet (Eleusine cora cana) and Rajmah (Phaseolus vulgaris) had the highest FRAP 471.71, 372.76 and DPPH scavenging activity 1.73, 1.07. Similar trends were observed with reducing power. Among cereals and legumes, Finger millet (Ragi) and black gram dhal (Phaseolus mungo Roxb) had the highest TPC, the values being 373 and 418 mg/100 g respectively, while rice (Oryza sativa) and green gram dhal (Phaseolus aureus Roxb) showed the least (47.6 and 62.4 mg/100 g). In the present study, FRAP (r = 0.91) and reducing power (r = 0.90) showed significant correlation with TPC in cereals and millets, but not in pulses and legumes. The results suggest that TPC contributes significantly to the AOA of Indian cereals and millets.

Local immunity in Indian women with bacterial vaginosis.

OBJECTIVES: To determine the immunoglobulin (Ig) and cytokine levels and degradation of Igs in the cervico-vaginal secretions (CVS) of non-pregnant Indian women of low socio economic status (LSES), with/without bacterial vaginosis (BV) and to assess the interactions among nutritional status, BV and local immunity. METHODS: A descriptive study in non-pregnant women of LSES attending the gynecology out patient clinic at a local government hospital, Hyderabad, India. Two hundred non-pregnant women underwent clinical, anthropometrical and gynecological examination and were screened for BV. In a sub-sample of 80 with/without BV, levels of IL-10 and IL-12, IgA, IgM and IgG were determined in the CVS by ELISA and degradation of IgA and IgM by Western blotting. Statistical significance among the groups was tested using the non-parametric Mann-Whitney U-test. RESULTS: Fifty seven percent of the women tested positive for BV. Women with BMI<16.0 had the highest BV positivity and the lowest IgA levels in CVS. Higher levels of IgA were observed in women with BMI>18.5. There was significant degradation of IgA and IgM in women with BV. IL-12 was undetectable while IL-10 was detected with higher means in CVS of women with BV. CONCLUSIONS: Severe under-nutrition appears to be relevant to BV positivity and local immunity in these women. Greater degradation of IgA and IgM in BV suggests impaired local immunity.

Addition of milk does not alter the antioxidant activity of black tea.

Tea is a polyphenol-rich beverage like wine and catechins are its chief polyphenols. Catechins have cardio-protective effects as they can scavenge free radicals and inhibit lipid peroxidation. Epidemiological studies indicate an inverse relation between tea consumption and the risk of cardiovascular and other chronic diseases. Addition of milk to black tea has been reported to adversely affect its beneficial effects, but the data are not unequivocal. Therefore, we assessed the effect of the addition of milk to black tea on its ability to modulate oxidative stress and antioxidant status in adult male human volunteers. Although the area under the curve of plasma catechins was lower on the consumption of tea with milk compared to black tea, it did not affect the beneficial effects of black tea on total plasma antioxidant activity, plasma resistance to oxidation induced ex vivo, and decreased plasma and urinary thiobarbituric acid reactive substance levels. The results suggest that addition of milk may not obviate the ability of black tea to modulate the antioxidant status of subjects and that consumption of black tea with/without milk prevents oxidative damage in vivo.

Serum dehydroepiandrosterone and lipid peroxides in human volunteers of different age groups.

The objective of the present study was to evaluate the changes in serum dehydroepiandrosterone (DHEA) and lipid peroxide levels during ageing in human subjects. Random blood samples were collected from a total of 128 apparently normal human volunteers of both sexes, whose age ranged between 21-70 years. The subjects were divided into groups of a decade years of age difference. Serum levels of dehydroepiandrosterone (DHEA), lipid peroxides as malondialdehyde (MDA), and insulin were analysed in all the subjects recruited in the study. In the present study there was decrease in serum DHEA levels with age (11.30 to 7.99 ng/ml). However the differences were significant only after 50 years up to 70 years. Serum MDA levels of these subjects were higher (3.91 to 4.74 ng/ml) as compared to the values reported earlier (2.64 to 3.94 ng/ml). The serum MDA levels also showed an increasing trend with age but the increase was significant only in the 40-50 years age group and values plateaud off at later ages. The MDA and DHEA levels in women in general were lower than in men and this could be due to female hormones, which are known to protect lipid against peroxidation. There was a significant negative correlation between age and DHEA (r=-0.311 P<0.05) and positive correction between MDA and age (r=+0.405 P<0.01). No significant differences were seen in serum insulin, albumin and total protein levels. These preliminary findings support the possible utility of DHEA and MDA as markers for chronological ageing.

Changes in biochemical indicators of iron status during iron repletion and depletion in monkeys.

Different modes of iron depletion and repletion were studied in monkeys to understand the sequential changes in and the relative importance of different biochemical indicators of iron status. Six control monkeys were divided into two groups, one was fed an iron-deficient diet (group 1) and the other underwent phlebotomy in addition to receiving an iron-deficient diet (group 2). Previously iron-depleted monkeys were subdivided into 4 groups of 3 animals each. While one group was continued on the iron-deficient diet (group 3), the second group received parenteral iron (group 4), the third group (group 5) received a sufficient-iron-containing diet, and the fourth group was fed 50% of the iron requirement. All indicators of iron status like hemoglobin (Hb), erythrocyte protoporphyrin (EPP), serum transferrin saturation and serum ferritin were monitored periodically, in addition to liver and bone marrow iron. all the indicators except serum ferritin and liver iron showed a decrease in group 2. On the other hand, animals receiving parenteral iron (group 4) showed an increase in all the parameters except serum ferritin. The dietary supplementation produced an increase in Hb and a decrease in EPP only (groups 5 and 6). There was a significant positive correlation between changes in bone marrow iron and Hb concentration depending on the severity of depletion and repletion. Both serum ferritin and liver iron did not respond to changes in dietary iron. Another parameter which responded to repletion was EPP. Serum ferritin and liver iron did not respond to changes in dietary iron or was not sensitive to subclinical iron deficiency. The results indicate that change in Hb is more sensitive to detect the deficiency of iron. It was also observed that different parameters respond variably under different modes of depletion and repletion.

Isolation and characterization of monkey liver ferritin.

Monkey liver ferritin was isolated and purified along with human liver ferritin and their physicochemical and immunological characteristics were compared. The apparent molecular weight of monkey liver ferritin was estimated to be 430 kDa as against 450 kDa of human liver ferritin. Both ferritins appeared to be made up of a 22.5 kDa polypeptide under denaturing conditions and the proteins contained neutral sugar (wt/wt) of 2.0% (monkey) and 2.4% (human). By immunoblots both human and monkey liver ferritins showed appreciable cross-reactivity with the polyclonal antibodies raised against either proteins. Monkey liver ferritin, however, was not recognised by the human monoclonal antibody. The amino acid composition of both ferritins was more or less similar. Isoelectric focusing indicated that monkey liver ferritin showed microheterogeneity with three bands at pI 5.4, 5.5 and 5.6, whereas human liver ferritin showed a single band at pI 5.6 confirming the relative acidic nature of monkey liver ferritin.

Induction of dietary iron deficiency in rhesus monkeys: sequential changes in serum ferritin and other biochemical indicators of iron status.

The usefulness of serum ferritin as a measure of subclinical stages of iron deficiency has been tested in monkeys by inducing a mild iron deficiency dietarily over a period of 12 months. Various biochemical indicators of iron status were measured periodically along with analysis of liver iron and iron staining of bone marrow samples obtained by biopsy, at the end of the experiment. A mild form of iron deficiency was confirmed by bone marrow staining for iron. Of all the biochemical indicators tested, significant decreases were seen in hemoglobin and hematocrit at the 11th and 10th months, respectively. These changes were consistent with the changes later found in bone marrow grading for iron. Serum ferritin concentration and liver iron concentration did not show any significant difference between the controls and iron-deficient monkeys. Thus, these results do not support the existence of a latent stage of iron deficiency. In the mild form of iron deficiency, the functional compartment, represented by bone marrow iron and hemoglobin, is sensitive to depletion even when there were no changes in storage compartment represented by liver iron and serum ferritin.

Distribution of iodine in marine foods from different regions of India.

The iodine content of fresh and processed marine fish collected from different parts of coastal India was analysed. It was found that Indian marine fish are rich in iodine content (mean of 193 +/- 82 micrograms/100 g on wet weight basis). Also the iodine contents of shell fish and crabs (0.7-2.5 mg/100 g on wet weight basis) were higher than that of other fish. No significant regional differences were noted in the iodine content of marine fish. Further, no differences were observed in case of either salted or sun-dried fish indicating that curing did not influence the iodine content.