Strategic Electrochemical Determination of Nitrate over Polyaniline/Multi-Walled Carbon Nanotubes-Gum Arabic Architecture.

Significant agricultural and industrial activities necessitate the regular monitoring of nitrate (NO3-) ions levels in feed and groundwater. The current comparative study discloses an innovative user-friendly electrochemical approach for the determination of NO3- over polyaniline (PAni)-based modified electrodes. The electrochemical sensors concocted with PAni, multi-walled carbon nanotubes (CNT), and gum arabic (GA). The unique electrode material GA@PAni-CNT was synthesized by facile one-pot catalytic polymerization of aniline (Ani) with FeCl3/H2O2 in the presence of CNT and GA as integral components. As revealed by cyclic voltammetry (CV), the anchoring/retention of NO3- followed by reduction is proposed to occur when a GA@PAni-CNT electrode is immersed in phosphate buffer electrolyte containing NO3- that eventually results in a significantly higher redox activity of the GA@PAni-CNT electrode upon potential scan. The mechanism of NO3- anchoring may be associated with the non-redox transition of leucomeraldine salt (LS) into emeraldine salt (ES) and the generation of nitrite (NO2-) ions. As a result, the oxidation current produced by CV for redox transition of ES ↔ pernigraniline (PN) was ~9 times of that obtained with GA@PAni-CNT electrode and phosphate buffer electrolyte, thus achieving indirect NO3- voltammetric determination of the GA@PAni-CNT electrode. The prepared GA@PAni-CNT electrode displayed a higher charge transfer ability as compared to that of PAni-CNT and PAni electrodes. The optimum square wave voltammetric (SWV) response resulted in two linear concentration ranges of 1-10 (R2 = 0.9995) and 15-50 µM (R2 = 0.9988) with a detection limit of 0.42 µM, which is significantly lower. The GA@PAni-CNT electrode demonstrated the best detection, sensitivity, and performance among the investigated electrodes for indirect voltammetric determination of NO3- that portrayed the possibility of utilizing GA-stabilized PAni and CNT nanocomposite materials in additional electrochemical sensing applications.

Detailed approach toward the anti-hyperglycemic potential of Sterculia diversifolia G. Don against alloxan-induced in vivo hyperglycemia model.

OBJECTIVE: To investigate Sterculia diversifolia G. Don for potential anti-diabetic activity in the in vivo mouse model of alloxan-induced hyperglycemia. METHODS: Sterculia diversifolia (S. diversifolia) was subjected to extraction and isolation techniques and structural characterization of the isolated compounds were performed using spectroscopic methods. The acute toxicity test was performed by orally administering S. diversifolia in doses of 500-2000 mg/kg. For the assessment of anti-hyperglycemic activity, S. diversifolia bark and leaves extracts were administered orally in doses of 50, 100, and 200 mg/kg, along with metformin (150 mg/kg, i.p) as positive control, after confirmation of alloxan (150 mg/kg, i.p.) induced hyperglycemia in BALB/c mice. Serum biochemical parameters were monitored for the period of study. RESULTS: The phytochemical studies showed the presence of quercetin and kaempferol in S. diversifolia. The IC50 values in the in vivo acute toxicity study revealed the safety margin of S. diversifolia bark (1166.66 mg/kg) and leaves (683.34 mg/kg) extracts. A significant attenuation of alloxan induced hyperglycemia was produced by S. diversifolia extracts at 50 mg/kg (P < 0.05), 100 mg/kg (P < 0.05, < 0.01), and 150 mg/kg (P < 0.05, < 0.01, < 0.001) during 1-4 h, which was comparable to metformin (P < 0.001). Significant (P < 0.001) improvement appeared in blood hemoglobin, protein, cholesterol, triglycerides, urea, creatinine, HDL, and LDL of the stem bark and leaves extracts treated diabetic mice. CONCLUSION: These findings connote the usefulness of S. diversifolia as an anti-diabetic in traditional medicine and this might be attributed to the presence of quercetin and kaempferol, among other phytochemicals.

In vivo laxative, anti-diarrheal, hepatoprotective and diuretic investigations of Sterculia diversifolia and its isolated compound.

OBJECTIVE: To investigated the laxative, anti-diarrheal, hepatoprotective and diuretic activity of Sterculia diversifolia and its isolated compounds. METHODS: The laxative activity was studied by counting wet stools while anti-diarrheal activity was performed by measuring gastrointestinal tract motility. Hepatoprotective activity was studied by biochemical and histo-pathological analysis while diuretic activity was performed by urine collection protocol. RESULTS: Doses of 30 and 100 mg/kg of crude methanolic extract of Sterculia diversifolia (MESD) stem bark and leaves, significantly (P < 0.05, P < 0.01) produced wet feces in subjects pretreated with atropine while 8-hydroxyquercetin and dihydroquercetin showed highly significant (P < 0.001) results by increasing fecal weight and water contents without producing diarrhea. MESD stem bark and leaves also dose-dependently lowered diarrhea while 8-hydroxyquercetin and dihydroquercetin showed highly significant (P < 0.001) results by producing shaped stools in mice. MESD, 8-hydroxyquercetin and dihydroquercetin offered significant protection against histopathological changes in the liver. Diuretic activity of Crude MESD stem bark and leaves extracts shows highly significant diuretic effect while dihydroquercetin showed better results than 8-hydroxyquercetin. CONCLUSION: It is concluded that Sterculia diversifolia and its isolated compounds bears laxative, anti-diarrheal, hepatoprotective and diuretic effects.

Potent anti-platelet constituents from Centaurea iberica.

New naturally occurring nitrogenous compounds 1 and 2, along with a new dimeric lignan glucoside 3, have been isolated from the ethyl acetate soluble fraction of Centaurea iberica. Their structures have been elucidated through spectroscopic techniques. All the isolated compounds showed significant platelet aggregation inhibition.

Conferin, potent antioxidant and anti-inflammatory isoflavone from Caragana conferta Benth.

Conferin (1), a new isoflavone, has been isolated from the ethyl acetate soluble fraction of Caragana conferta Benth. along with seven known compounds, namely biochanin A (2), p-hydroxybenzoic acid (3), 3,5-dimethoxybenzoic acid (4), ursolic acid (5), erythrodiol (6), pinoresinol (7), and syringresinol (8), reported for the first time from this species. The structure of the new isoflavone was deduced on the basis of spectroscopic studies. Compounds 1 and 2 were investigated for biological activities and showed significant anti-inflammatory activity in carrageenan induced paw edema of rats. Evaluation of antioxidant activity by the radical scavenging method indicated that compound 1 is a potent antioxidant while 2 is moderately active. It was also shown that the reducing capability of compound 2 was remarkably increased in a concentration dependent manner as compared to 1. Compound 1 showed moderate inhibitory activity against the enzyme lipoxygenase, while 2 showed weak activity.