NOPR Collection: [Pages 73-140]

Time course evaluation of provitamin A carotenoids stored under different storage regimens in maize

2021-02-01T07:05:42Z

Title: Time course evaluation of provitamin A carotenoids stored under different storage regimens in maize Authors: Kaur, Harmanjot; Das, Abhijit Kumar; Sethi, Mehak; Choudhary, Mukesh; Rakshit, Sujay; Chaudhary, Dharam Paul Abstract: Yellow maize is natural source of provitamin A components. However, the provitamin A carotenoids are known to degrade fast as a result of oxidation and isomerization due to exposure to heat and oxygen during storage. Keeping this in view, here, we evaluated the provitamin A carotenoids in maize stored under different storage conditions. For this purpose, F₂ grains of six hybrids consisting of two provitamin A rich, two QPM and two normal maize were stored in earthen pot, aluminium box, cotton cloth and jute bag for a period of 6 months under ambient temperature and carotenoid components were estimated at monthly interval. Provitamin A components are found to reduce significantly within two to six months under various storage conditions. However, the samples stored in aluminium box exhibited least degradation of β-carotene (73%) and β-cryptoxanthin (81%), whereas those stored in earthen pot exhibited highest degradation of β-carotene (86%) and β-cryptoxanthin (90%), after six months of storage. The provitamin A rich hybrids especially APH27 retained highest concentration of provitamin A carotenoids after six months of storage. The least losses observed in the samples stored in aluminium box may be attributed to reduced oxidation and least light penetration. Page(s): 79-87

Salivary amylase from Chilo partellus (Swinhoe) — Characterization and mode of inhibition through analysis of double reciprocal, fractional velocity and combination plots

2021-02-01T07:03:22Z

Title: Salivary amylase from Chilo partellus (Swinhoe) — Characterization and mode of inhibition through analysis of double reciprocal, fractional velocity and combination plots Authors: Kaur, Sarbjit; Kaur, Kamaljit; Jindal, Jawala; Kaur, Gurjit Abstract: The stem borer Chilo partellus (Swinhoe) is the most devastating pest that causes huge losses to agricultural productivity. Being a herbivorous insect, the starch degrading enzyme, salivary amylase, plays a crucial role in its digestive system. The characterization of salivary amylase and targeting it with potent inhibitors could help in managing the pest by hindering its normal digestive process. Therefore, we have made an attempt to characterize the enzyme and analyze its nature of interaction with organic acids and inorganic salts. The salivary amylase was purified by G-100 column chromatography to 16.02 folds and biochemically characterized. The purified fraction consisted of α-amylase activity with a single isoform of 59.26 kDa. It showed an optimum pH between 6.0 and 7.0. Its optimum temperature was 40 °C and was thermally stable up to 70 °C. Starch was the preferred substrate of salivary amylase. By critical analysis of Lineweaver-Burk, Eadie- Hofstee and Hanes plots, the Km and Vmax values of salivary amylase for starch were confirmed to be 0.49 mg/mL and 1.67 nmoles of reducing sugars formed/min/mL, respectively. Zinc chloride, calcium nitrate, salicylic acid, citric acid and oxalic acid were found to be potent inhibitors of salivary α-amylase activity. From Lineweaver-Burk, fractional velocity and combination plots, it was inferred that citric acid was a pure non-competitive inhibitor of salivary α-amylase while salicylic acid, oxalic acid and zinc chloride caused complete mixed non-competitive- competitive inhibitions. The inhibition of salivary α-amylase with calcium nitrate was of complete mixed non-competitive- uncompetitive type. Page(s): 88-96

Correlation between prolidase activity and spatial memory functions in streptozotocin-induced diabetic rats

2021-02-01T06:57:19Z

Title: Correlation between prolidase activity and spatial memory functions in streptozotocin-induced diabetic rats Authors: Prabha, Lakshmi M; Subramanian, Sarada Abstract: In the present study, we investigated the association of prolidase activity in streptozotocin (STZ) induced diabetic rat model with hippocampus-dependent spatial memory functions in chronic hyperglycemic conditions. Towards this, a single dose of STZ (30 mg/kg, i.p.) was administered to 4-month-old female Sprague Dawley rats and hyperglycemia was confirmed in all the STZ treated rats. To assess the spatial memory, at the time intervals of 9 days, 30 days and 90 days post STZ administration, the animals were subjected to Barnes maze task. Prolidase activity and glucose concentration in the serum were measured at these time points. With prolonged duration of hyperglycemia, severe impairment in spatial memory functions was seen in STZ induced diabetic rats which was correlatable with reduction in prolidase levels (P <0.05), thus suggesting that alterations in synaptic integrity due to prolidase mediated extracellular matrix remodeling as the possible mechanism of memory defects observed during chronic diabetes. Page(s): 97-101

Antidiabetic and antioxidant potential of Durio zibethinus Murr. leaves ethanolic extract

2021-03-26T05:33:54Z

Title: Antidiabetic and antioxidant potential of Durio zibethinus Murr. leaves ethanolic extract Authors: Chigurupati, Sridevi Abstract: Durio zibethinus Murr., commonly called Durian, though well known for its rich medicinal uses, only fewer studies are available on the leaves of this plant. In this study, we investigated the antioxidant and antidiabetic potential of ethanol extract of D. zibethinus leaves (DZL) from Malaysian geographical origin. DZL was subjected to the preliminary phytochemical screening along with the quantitative analysis of phenols and flavonoids. The in vitro antioxidant properties were evaluated by DPPH and ABTS methods and in vitro antidiabetic properties were evaluated by α-amylase and α-glucosidase enzyme inhibition studies. The results of the above biological activities were expressed as inhibitory concentration 50% for DZL and standard drugs (acarbose and ascorbic acid). Based on the acute oral toxicity test, two test doses (100 and 200 mg/kg) of DZL were compared with glibenclamide (5 mg/kg) for their effect on fasting blood glucose at various time intervals (0 to12 h) in glucose-loaded normoglycemic rats. DZL (200 mg/kg) showed a better response in streptozotocin (STZ) induced diabetic rats. The antioxidant assay of DZL showed an appreciable extract inhibitory concentration 50% against the free radicals generated by DPPH (1.61±0.07 μg/ mL) and ABTS (1.47±0.07 μg/mL) assays. Similarly, the in vitro antidiabetic assay results demonstrated a dose-dependent inhibition of α-amylase (2.58±0.08 μg/mL) and α-glucosidase enzymes (2.41±0.08 μg/ mL) by DZL. Both glucose-loaded normoglycemic rats and STZ-induced diabetic rats treated with DZL (200 mg/kg) exhibited a significant post-dose reduction in blood glucose levels (P <0.01, 8 h and P <0.001, 12 h) when compared to normal and diabetic control rats, respectively. These findings suggest that the presence of polyphenols in DZL might be responsible for antioxidant and antidiabetic properties and DZL could be a natural source as an herbal remedy for diabetes. Page(s): 102-110