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Purpose: Persistent hyperglycemia lead towards depletion of hydrogen sulfide (H 2 S) resulting in generation of oxidative stress and diabetic nephropathy. The aim of the current study was to explore the antioxidant potential of H 2 S and captopril, a -SH containing compound in streptozotocin (STZ)-induced diabetic nephropathy., Methods: Fifty four Wistar-Kyoto (WKY) rats male (200-250g) were divided into nine groups (n=6) with each group injected once with STZ (60mg/kg i.p) except normal control. After 3 weeks of induction of diabetes, groups were assigned as normal control, diabetic control, diabetic-captopril, diabetic-NaHS, diabetic-captopril-NaHS, diabetic-spironolactone, diabetic-metformin, diabetic-metformin-NaHS and diabetic-vitamin-c. All the animals were served with normal saline (N/S 4mL/kg p.o), captopril (50mg/kg/day p.o), sodium hydrosulfide (NaHS) (56µmol/kg i.p), spironolactone (50mg/kg/day s.c), metformin (500mg/kg/day p.o) and vitamin-c (50mg/kg p.o) on daily basis for next 4 weeks, respectively. Metabolic studies, H 2 S levels, renal hemodynamics and oxidative stress markers were analyzed at 0, 14 and 28 days followed by histopathological analysis of renal tissues., Results: The results showed decreased H 2 S levels, body weight, sodium to potassium ratio, glutathione (GSH), superoxide dismutase (SOD), total antioxidant assay (T-AOC) with malondialdehyde (MDA) and blood glucose levels significantly increased among diabetic rats. Treatment with captopril, NaHS, metformin, spironolactone and vitamin C showed significant improvement among renal hemodynamics and oxidative stress markers, respectively. But treatment groups like NaHS in combination with captopril and metformin showed more pronounced effects., Conclusion: The observations suggest that H 2 S mediated protective effects on STZ-induced diabetic nephropathy may be associated with reduced oxidative stress via augmenting the antioxidant effect., Competing Interests: The authors declare no conflict of interest., (© 2021 Hussain Lodhi et al.)

Drought stress is one of the extreme effects of climate change causing large losses in production of crop plants. The risk of recurrent droughts has increased in next decades hence, the development of shot-gun, inexpensive and effective approaches is essential to ensure high yield of crops in drought-prone areas of the world. Exogenous application of nutrients such as potassium (K) has been reported to increase abiotic resistance and improve yield in crops however, knowledge regarding interaction of K with osmoprotectants like chitosan (Ct) still remains elusive. Here, we report the effects of individual or combined K (using K 2 SO 4 as a source) or Ct application on growth, physiological processes and antioxidative defense system of sunflower under drought stress. At first, various doses of K (0, 5, 10, 15, 20, 25 g/l) and Ct (0, 0.1, 0.2, 0.3, 0.4, 0.5 g/l) were foliar applied to evaluate their role in improving plant biomass, water status and total chlorophyll in drought-induced seedlings of sunflower. The optimized K (11.48 g/l) and Ct (0.28 g/l) doses were further tested in second experiment to understand the underlying mechanisms of drought tolerance. Foliar K + Ct spray markedly enhanced the leaf gas exchange characteristics, increased proline, soluble proteins, and free amino acids, upregulated antioxidant defense system and helped to maintain plant water status in sunflower exposed to drought stress. The impact of drought stress was more pronounced at vegetative than reproductive stage and positive effects of combined K and Ct application were related to improved physiological and metabolic processes to improve yield and quality of sunflower under drought stress., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Antioxidants play an important role in animal and plant life owing to their involvement in complex metabolic and signaling mechanisms, hence uncovering the genetic basis associated with antioxidant activity is very important for the development of improved varieties. Here, a total of 182 common bean ( Phaseolus vulgaris ) landraces and six commercial cultivars collected from 19 provinces of Turkey were evaluated for seed antioxidant activity under four environments and two locations. Antioxidant activity was measured using ABTS radical scavenging capacity and mean antioxidant activity in common bean landraces was 20.03 µmol TE/g. Analysis of variance reflected that genotype by environment interaction was statistically non-significant and heritability analysis showed higher heritability of antioxidant activity. Variations in seed color were observed, and a higher antioxidant activity was present in seeds having colored seed as compared to those having white seeds. A negative correlation was found between white-colored seeds and antioxidant activity. A total of 7900 DArTseq markers were used to explore the population structure that grouped the studied germplasm into two sub-populations on the basis of their geographical origins and trolox equivalent antioxidant capacity contents. Mean linkage disequilibrium (LD) was 54%, and mean LD decay was 1.15 Mb. Mixed linear model i.e., the Q + K model demonstrated that four DArTseq markers had significant association ( p < 0.01) for antioxidant activity. Three of these markers were present on chromosome Pv07, while the fourth marker was located on chromosome Pv03. Among the identified markers, DArT-3369938 marker showed maximum (14.61%) variation. A total of four putative candidate genes were predicted from sequences reflecting homology to identified DArTseq markers. This is a pioneering study involving the identification of association for antioxidant activity in common bean seeds. We envisage that this study will be very helpful for global common bean breeding community in order to develop cultivars with higher antioxidant activity.

Oxidative stress and suppressed H2S production lead to increased renal vascular resistance, disturbed glomerular hemodynamics, and abnormal renal sodium and water handling, contribute to the pathogenesis and maintenance of essential hypertension in man and the spontaneously hypertensive rat. This study investigated the impact of H2S and tempol alone and in combination on blood pressure and renal hemodynamics and excretory functions in the SHR. Groups of WKY rats or SHR (n=6) were treated for 4 weeks either as controls or received NaHS (SHR+NaHS), tempol (SHR+Tempol), or NaHS plus tempol (SHR+NaHS +Tempol). Metabolic studies were performed on days 0, 14, and 28, thereafter animals were anaesthetized to measure renal hemodynamics and plasma oxidative and antioxidant markers. SHR control rats had higher mean arterial blood pressure (140.0 ± 2 vs. 100.0 ± 3 mmHg), lower plasma and urinary H2S, creatinine clearance, urine flow rate and urinary sodium excretion, and oxidative stress compared to WKY (all p<0.05). Treatment either with NaHS or with tempol alone decreased blood pressure and oxidative stress and improved renal hemodynamic and excretory function compared to untreated SHR. Combined NaHS and tempol therapy in SHRs caused larger decreases in blood pressure (∼20-22% vs. ∼11-15% and ∼10-14%), increases in creatinine clearance, urinary sodium excretion and fractional sodium excretion and up-regulated the antioxidant status compared to each agent alone (all p<0.05). These findings demonstrated that H2S and tempol together resulted in greater reductions in blood pressure and normalization of kidney function compared with either compound alone.

Antioxidants play an important role in animal and plant life owing to their involvement in complex metabolic and signaling mechanisms, hence uncovering the genetic basis associated with antioxidant activity is very important for the development of improved varieties. Here, a total of 182 common bean (Phaseolus vulgaris) landraces and six commercial cultivars collected from 19 provinces of Turkey were evaluated for seed antioxidant activity under four environments and two locations. Antioxidant activity was measured using ABTS radical scavenging capacity and mean antioxidant activity in common bean landraces was 20.03 µmol TE/g. Analysis of variance reflected that genotype by environment interaction was statistically non-significant and heritability analysis showed higher heritability of antioxidant activity. Variations in seed color were observed, and a higher antioxidant activity was present in seeds having colored seed as compared to those having white seeds. A negative correlation was found between white-colored seeds and antioxidant activity. A total of 7900 DArTseq markers were used to explore the population structure that grouped the studied germplasm into two sub-populations on the basis of their geographical origins and trolox equivalent antioxidant capacity contents. Mean linkage disequilibrium (LD) was 54%, and mean LD decay was 1.15 Mb. Mixed linear model i.e., the Q + K model demonstrated that four DArTseq markers had significant association (p < 0.01) for antioxidant activity. Three of these markers were present on chromosome Pv07, while the fourth marker was located on chromosome Pv03. Among the identified markers, DArT-3369938 marker showed maximum (14.61%) variation. A total of four putative candidate genes were predicted from sequences reflecting homology to identified DArTseq markers. This is a pioneering study involving the identification of association for antioxidant activity in common bean seeds. We envisage that this study will be very helpful for global common bean breeding community in order to develop cultivars with higher antioxidant activity. [ABSTRACT FROM AUTHOR]

A greenhouse experiment was conducted to evaluate the comparison of nutrient use efficiency, antioxidant assay, and nutritional quality of butter-head lettuce in five cultivation systems. For this experimental study, a split-boxes experimental arrangement in a completely randomized design (CRD) with three aeroponics systems (high pressure (T1), low pressure (T2), and ultrasonic nozzle (T3)), hydroponic system (T4), and conventional cultivation system (T5) was designed. The analyses of variance (ANOVA) were employed to assess yield, chlorophyll content, relative water content (RWC), nutrient use efficiency (NUE), 2,2-Diphenyl-1-picrylhydrazyl (DDPH), Hydrogen Peroxide (H2O2), Ferric Reducing Antioxidant Power (FRAP), total phenolic (TPC), flavonoid content (TFC) and nutritional quality of butter-head lettuce. The experimental comparative results indicated that the shoot and root (fresh and dry) weight, root-to-shoot ratio, chlorophyll contents, CWC, NUE, DDPH, H2O2, FRAP, TPC, TFC, nitrate, vitamin C, and protein level were significantly (p<0.05) higher in T2 treatment, and the values were significantly (p<0.05) lower in T1 followed by T5 treatment. Moreover, as mentioned earlier, the median values of the above-mentioned parameters were measured in aeroponics systems with low-pressure nozzle (T3). It also found a strong positive correlation (r>0.7) among the Shoot (FW), Chlorophyll, RWC, NUE, and among TPC, TFC, DDPH, H2O2, and FRAP. This study demonstrates that butter-head lettuce grown in aeroponics systems with high-pressure nozzles may serve as a potential dietary source and is rich in natural antioxidants. [ABSTRACT FROM AUTHOR]

Abstract: The aim of the present study was to quantify phenolic acids and flavonoids from Citrullus colocynthis roots (CCR), leaves (CCL) fruits (CCF) and compare the antioxidant and free radical scavenging activities of their extracts and major compounds. Reverse phase high performance liquid chromatography method was developed and validated for the simultaneous quantification of phenolic acids and flavonoids from ethanol and hexane extracts of CCR, CCL and CCF. The antioxidant activity of CCR, CCL and CCF extracts was investigated by measuring total phenolics, total flavonoids contents, DPPH free radical scavenging activity, inhibition of linoleic acid peroxidation and reducing power. The RP-HPLC analysis of C. colocynthis extracts revealed the presence of ferulic acid, vanillic acid, p-coumeric acid, gallic acid, p-hydroxy benzoic acid and chlorogenic acid being the major phenolic acids and quercetin, myricetin and catechin being the most prominent flavonoids compounds. The amounts of TP (3.07–18.6mg/g of dry plant material, measured as gallic acid equivalent) and TF (0.51–13.9mg/g of dry plant material, measured as catechin equivalent) were higher in ethanol extracts of CCL, followed by CCR and CCF. Ethanol extract of CCL exhibited the highest antioxidant and DPPH radical scavenging activities followed by ethanol extracts of CCR and CCF. However, only hexane extract of CCF showed considerable DPPH radical scavenging activity. The results suggested that CCR, CCL and CCF extracts showed a wide variability of their phenolic acids and flavonoids composition and antioxidant activity. [Copyright &y& Elsevier]