Neuroprotective effect of Decalepis hamiltonii aqueous root extract and purified 2-hydroxy-4-methoxy benzaldehyde on 6-OHDA induced neurotoxicity in Caenorhabditis elegans.

In this study, we investigated the possible neuroprotective efficacy of Decalepis hamiltonii tuber extract against 6-Hydroxy dopamine (6-OHDA) induced neurotoxicity and associated effects in Caenorhabditis elegans. The major component of flavour rich extract from D. hamiltonii is 2-hydroxy-4-methoxy benzaldehyde (2H4MB) which is an isomer of vanillin. We have conducted preliminary experiments with different types of extracts and subsequently DHFE (D. hamiltonii Fresh Tuber Extract) and DHPF (D. hamiltonii purified 2H4MB fraction) were used for further studies. Here we attempted to enumerate the neuroprotective efficacy of the above compounds in worms by evaluating behavioural and mitochondrial function, dopamine content and selective degeneration of dopaminergic neurons in BZ555 strains in comparison with control and 6-OHDA treated organisms. The relative expression levels of selected antioxidant genes involved in defence mechanism like SOD-3, GST-2 and GST-4 were evaluated along with those of CAT-2 and DOP-2 at mRNA level. We observed that both DHPF and DHFE exhibited significant levels of neuroprotective property against 6-OHDA induced neurotoxicity, which was evident in mitochondrial/dopaminergic function and antioxidant defence mechanism.

Alpha-linolenic acid suppresses dopaminergic neurodegeneration induced by 6-OHDA in C. elegans.

Parkinson's disease (PD) is the second most common neurodegenerative disorder characterized by the specific and massive loss of dopamine (DA) containing neurons in the substantia nigra pars compacta (SNpc) and aggregation of protein α-synuclein. There are a few animal studies, which indirectly implicate the neuroprotective action of omega-3 polyunsaturated fatty acids in neurodegenerative diseases. In this study, we exposed Caenorhabditis elegans (both wild type N2, and transgenic strain, UA44) to 6-hydroxydopamine (6-OHDA, the model neurotoxicant) and evaluated the extent of protection offered by alpha-linolenic acid (ALA). Larval stage worms (L1/L2) of N2 and transgenic strains were exposed to 6-OHDA (25 mM) with or without ALA (10, 50 and 100 µM) for 48 h at 20 °C. After 48 h, while the N2 worms were assessed for their responses in terms of locomotion, pharyngeal pumping, lifespan and AChE activity, the transgenic worms were monitored for dopaminergic neuronal degeneration. Worms exposed to 6-OHDA exhibited a significant reduction (48%) in the locomotion rate. Interestingly, supplementation with ALA increased the locomotion rate in 6-OHDA treated worms. A marked decrease (45%) in thrashing was evident in worms exposed to 6-OHDA while thrashing was slightly improved in worms co-exposed to 6-OHDA and higher concentrations of ALA. Interestingly, worms co-exposed to 6-OHDA with ALA (100 µM) exhibited a significant increase in thrashing (66 ± 1.80 thrashes/30s). The pharyngeal pumping rate declined significantly in the case of worms exposed to 6-OHDA (35%). However, the worms co-treated with ALA exhibited significant recovery in pharyngeal pumping. The mean survival for the control worms was 26 days, while the worms exposed to 6-OHDA, showed a marked reduction in survival (21 days). Worms co-exposed to 6-OHDA and ALA showed a concentration-dependent increase in lifespan compared to those exposed to 6-OHDA alone (23, 25 and 26 days respectively). Transgenic worms treated with 6-OHDA showed significant loss of processes of CEP and ADE neurons as evident from visibly marked reduction in GFP expression. Worms co-exposed to 6-OHDA and ALA showed visibly significant reduction in neuronal degeneration in both CEP and ADE. However, worms exposed to 6-OHDA together with ALA showed increased GFP expression within processes of CEP and ADE neurons. Overall, our results demonstrate that ALA significantly suppresses the dopaminergic neurodegeneration and movement disorder induced by 6-OHDA in C. elegans.

Antioxidant-mediated protective effect of potato peel extract in erythrocytes against oxidative damage.

Potato peels are waste by-product of the potato processing industry. They are reportedly rich in polyphenols. Our earlier studies have shown that extracts derived from potato peel (PPE) possess strong antioxidant activity in chemical and biological model systems in vitro, attributable to its polyphenolic content. The main objective of this study was to investigate the ability of PPE to protect erythrocytes against oxidative damage, in vitro. The protection rendered by PPE in erythrocytes was studied in terms of resistance to oxidative damage, morphological alterations as well as membrane structural alterations. The total polyphenolic content in PPE was found to be 3.93 mg/g powder. The major phenolic acids present in PPE were predominantly: gallic acid, caffeic acid, chlorogenic acid and protocatechuic acid. We chose the experimental prooxidant system: FeSO(4) and ascorbic acid to induce lipid peroxidation in rat RBCs and human RBC membranes. PPE was found to inhibit lipid peroxidation with similar effectiveness in both the systems (about 80-85% inhibition by PPE at 2.5 mg/ml). While PPE per se did not cause any morphological alteration in the erythrocytes, under the experimental conditions, PPE significantly inhibited the H(2)O(2)-induced morphological alterations in rat RBCs as revealed by scanning electron microscopy. Further, PPE was found to offer significant protection to human erythrocyte membrane proteins from oxidative damage induced by ferrous-ascorbate. In conclusion, our results indicate that PPE is capable of protecting erythrocytes against oxidative damage probably by acting as a strong antioxidant.

Angiotensin converting enzyme inhibitory activity of amino acid esters of carbohydrates.

L-alanyl-D-glucose, L-valyl-D-glucose, L-phenylalanyl-D-glucose and L-phenylalanyl-lactose esters were synthesized enzymatically using two lipases viz., Rhizomucor miehei lipase (RML) and porcine pancreas lipase (PPL) and tested for their potential as inhibitors of angiotensin converting enzyme (ACE) in vitro. The esters exhibited concentration related ACE inhibitory activity. The potency of the various esters measured in terms of IC50 values were as follows: L-phenylalanyl-D-glucose, IC50-0.121 mM (mixture of five diastereomeric esters: 6-O-24.1%; 3-O-23.3%; 2-O-19.2%; 2,6-di-O-16.6% and 3,6-di-O-16.8% from the total yield of 92.4%); L-phenylalanyl-lactose, IC50-0.229 mM (mixture of three diastereomeric esters: 6-O-42.1%; 6'-O-30.9%; and 6,6'-di-O-27.0% from the total yield of 50.58%); alanyl-D-glucose, IC50-0.23 mM (mixture of five diastereomeric esters: 6-O-46.7%; 3-O-11.5%; 2-O-19.9%; 2,6-di-O-6.6% and 3,6-di-O-15.3% from the total yield of 26.5%) and L-valyl-D-glucose, IC50-0.396 mM (mixture of five diastereomeric esters: 6-O-32.4%; 3-O-26.5%; 2-O-26.4%; 2,6-di-O-8.8% and 3,6-di-O-5.9% from the total yield of 68.2%). These in vitro data suggest a potential therapeutic role for the aminoesters of carbohydrates as inhibibitors of ACE.

Protective effect of potato peel powder in ameliorating oxidative stress in streptozotocin diabetic rats.

The potential of dietary potato peel (PP) powder in ameliorating oxidative stress (OS) and hyperglycemia was investigated in streptozotocin (STZ)-induced diabetic rats. In a 4-week feeding trial, incorporation of potato peel powder (5 and 10%) in the diet of diabetic rats was found to significantly reduce the plasma glucose level and also reduce drastically the polyuria of STZ diabetic rats. The total food intake was significantly reduced in the diabetic rats fed 10% PP powder compared to the control diabetic rats. However, the body weight gain over 28 days was nearly four times greater in PP powder supplemented diabetic rats (both at 5 and 10%) compared to the control diabetic rats. PP powder in the diet also decreased the elevated activities of serum transaminases (ALT and AST) and nearly normalized the hepatic MDA and GSH levels as well as the activities of specific antioxidant enzymes in liver of diabetic rats. The result of these studies clearly establishes the modulatory propensity of PP against diabetes induced alterations. Considering that potato peels are discarded as waste and not effectively utilized, these results suggest the possibility that PP waste could be effectively used as an ingredient in health and functional food to ameliorate certain disease states such as diabetes.

Fenvalerate-induced oxidative damage in rat tissues and its attenuation by dietary sesame oil.

The primary objective of this study was to investigate the propensity of Fenvalerate (FEN), a synthetic pyrethroid to induce oxidative stress (OS) in various tissues of growing male rats following a short-term (28 days) dietary regimen and its possible attenuation by dietary (10%) sesame oil (SO). FEN incorporated diet was fed to weanling male rats at the dosages of 0, 250, 500 and 1000 ppm. Terminally, significant induction of OS in liver, thymus, spleen and erythrocytes was noticed at higher doses as evidenced by the elevated levels of lipid peroxidation (LPO). Significant dose-dependent depletion of GSH levels, perturbations in antioxidant enzymes, and enhanced protein carbonyls further confirmed the potential of FEN to induce OS in hepatic tissue. In addition, FEN also caused significant increases in activities of hepatic transaminases, ALP and LDH. Interestingly, dietary SO significantly attenuated FEN-induced oxidative damage in liver and other tissues. The degree of protection was remarkably high, since LPO and GSH status, protein carbonyl content and antioxidant defenses in liver and other tissues were brought down to basal levels in the SO + FEN1ooo group. These results clearly indicate the potential of FEN to induce oxidative damage in vivo and also suggest the ability of SO, a dietary fat to significantly offset the oxidative damage which may related to the presence of antioxidant compounds in the oil.

Attenuation of hyperglycemia and associated biochemical parameters in STZ-induced diabetic rats by dietary supplementation of potato peel powder.

BACKGROUND: Both dietary fiber and polyphenols have been reported to exert antihyperglycemic effect. Potato peel (PP), a waste by product of potato processing, is found to be a good source of both dietary fiber and polyphenols. The current study examined the attenuating influence of dietary potato peel (PP) powder on hyperglycemia and various oxidative stress-associated biochemical parameters in diabetic rats. METHODS: Streptozotocin (STZ)-induced diabetic male Wistar rats were used as experimental models. The rats were divided into nondiabetic (control), diabetic, potato-peel-supplemented (5% and 10%) and diabetic-PP (5% and 10%)-supplemented groups and were maintained for 4 weeks on the experimental regime. The modulatory role of PP was assessed by determining its effect on blood glucose, urine output, body weight gain, lipid peroxidation, reduced glutathione, serum aminotransferases, lipid profiles, selected antioxidant enzymes in liver/kidney and selected eye lens parameters. RESULTS: Diabetic rats fed with PP-powder-supplemented diet for 4 weeks showed a significant decrease in blood glucose levels. Incorporation of PP powder reduced significantly the hypertrophy of both liver and kidney of STZ-diabetic rats and also normalized the activities of serum ALT and AST, hepatic and renal MDA and GSH, as well as activities of various antioxidant enzymes in liver and kidney of diabetic rats. Furthermore, PP powder in the diet also appeared to attenuate the eye lens damage associated with the diabetic condition. CONCLUSION: Potato peel powder supplementation in diet was found to effectively attenuate diabetic alterations in rats.

Cytotoxicity of certain organic solvents and organophosphorus insecticides to the ciliated protozoan Paramecium caudatum.

Responses of Paramecium caudatum, a ciliated protozoan, to acute exposures of certain organic solvents and organophosphorus insecticides (OPI) were studied by determining their lethal concentration (10 min-LC100) and median lethal concentration (4 h-LC50). The solvents and OPI evoked a distinct sequence of responses. Among the five solvents tested, acetone proved most toxic [LC-2.9% and LC50-0.68% (v/v)], while dimethyl sulphoxide (DMSO) showed least toxicity [LC-11.0% and LC50-3.16% (v/v)]. The order of toxicity of solvents was: acetone greater than ethanol greater than methanol greater than N, N-dimethylformamide greater than dimethylsulphoxide. The LC values of six OPI dissolved in either acetone or DMSO indicated that they were more toxic when dissolved in acetone and least toxic in DMSO. Among the OPI, bromophos proved most toxic (LC-10 ppm) while malathion showed least toxicity (LC-200 ppm) in DMSO. The order of toxicity of OPI was: bromophos greater than pirimiphos-methyl greater than parathion methyl greater than dichlorvos greater than fenitrothion greater than malathion. The 4 h-LC50 values computed for bromophos and malathion (dissolved in DMSO) were 575 ppb and 19.9 ppm, respectively, indicating the high susceptibility of P. caudatum to bromophos. The results indicate that the Paramecium toxicity assay could be used as a complementary system to rapidly elucidate the cytotoxic potential of compounds.

Effect of L-ascorbic acid supplementation on the toxicity of pirimiphos-methyl to albino rats.

The effect of L-ascorbic acid supplementation on Pirimiphos-methyl induced toxicity was studied in albino rats. Biochemical estimations were made in rats administered orally the insecticide at 100 and 200 mg/kg body weight with or without oral supplementation of L-ascorbic acid at 200 mg/kg b.w. The biochemical assessments included estimations of brain and plasma cholinesterases, levels of ascorbic acid in liver, kidney and adrenals, urinary levels of ascorbic acid and glucuronic acid. A lower degree of inhibition of the cholinesterases were evident in ascorbic acid supplemented rats. Marked elevation in urinary levels of ascorbic acid and glucuronic acid was observed in the insecticide treated rats. Results of this study suggests that L-ascorbic acid supplementation partially offsets Pirimiphos-methyl induced toxicity.