SNP-induced Lipid Peroxidation Research Articles

Chemical Composition and Antioxidant Potential of Leaf Essential Oils of Ocimum Canum Sims Harvested at Various Times Daily

Fresh Ocimum canum leaves were harvested five times at interval of three hours in a twelve hour-cycle daily (7:00, 10:00, 13:00, 16:00, and 19:00 hours). The leaves from each harvest were separately subjected to hydrodistillation for three hours in a Clevenger-type apparatus. The oils obtained were analyzed by Gas Chromatography (GC) and Gas Chromatography-Mass Spectrometry (GC-MS). Cluster analysis was used (based on the data, select variables > 0.2% of 43 oil components from five harvest times) to classify the oils. Antioxidant potential of the oils were determined using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and Sodium Nitroprusside (SNP)-Induced Lipid Peroxidation assays. The oils afforded yield in the range of 0.15-0.23% (w/w), with the highest and lowest yields observed at 7:00 and 13:00 hours respectively. A total of 23-40 compounds, representing 99.4-99.8% of the total oils were identified from their mass spectra with predominance of oxygenated monoterpenoids (50-65.7%), hydrogenated monoterpenoids accounted for 5.4-19.1%, whereas hydrogenated sesquiterpenoids constituted between 10.1-21.4% of the total oils. The most abundant compound was linalool (46.7-52.4%), other major compounds identified were terpinen-4-ol (8.5-9.5%), eugenol (1.9-10%) and trans-α-bergamotene (5.5-10.2%). Cluster analysis revealed a significant variability within the oil samples obtained from various harvest times. The oils presented a considerable antioxidant activity (IC50 of 5.45-10.87µg/ml compared with 4.05-6.11µg/ml for BHT standard) for DPPH assay; and (3.86- 5.36 µg/ml compared with 2.12-4.33 µg/ml for BHA standard) for SNP-Induced lipid peroxidation assay. The oil obtained from 10:00 hours harvest had the best antioxidant activity at IC50 for both assays. Chemical composition and antioxidant activity of the oils varied significantly with harvest times. The oils exhibited antioxidant property comparable to those of standards, hence could serve as cheaper and safer alternative to synthetic drugs to ameliorate oxidative stress after clinical trials.

Enhancement of polyphenols and antioxidant and inhibitory properties of Corchorus olitorius and Amaranthus hybridus leaves by the Ultraviolet-C treatment

The effect of the postharvest (Ultraviolet-C) treatment on total phenolics, total flavonoids, total antioxidant capacity, 1,1-diphenyl-2-picrylhydrazyl scavenging activity(DPPH),and reducing power of Corchorus olitorius(CO) and Amaranthus hybridus(AH)was investigated. Their abilities to inhibit induced lipid peroxidation, α-amylase,and α-glucosidase after the ultraviolet-C treatment were also evaluated. The leaves were exposed to ultraviolet-C radiation for 10 min. Total phenolics, total flavonoids, total antioxidant capacity, DPPH scavenging ability,and reducing power were significantly (p < 0.05) increased after the ultraviolet-C treatment. Also,their abilities to inhibit SNP-induced lipid peroxidation, α-amylase and α-glucosidase were also enhanced significantly (p < 0.05). Therefore,apart from using ultraviolet-C radiation in water purification, it can be used to enhance health-promoting components in fruit and vegetables.

Ameliorative effect of Parinari curatellifolia seed extracts on sodium nitroprusside–induced cardiovascular toxicity in rats

The pharmacological potential of Parinari curatellifolia has remained largely unexplored by the scientific community and little information is available to support the folkloric and ethnobotanical uses of the plant. This present study was carried out to investigate the ameliorative effect of P. curatellifolia seed extracts on sodium nitroprusside (SNP) toxicity on the heart and artery in rats. P. curatellifolia seed crude aqueous-methanolic extract (CMPC) as well as n-hexane (HFPC), dichloromethane (DFPC), ethyl acetate (EFPC), and n-butanolic (BFPC) fractions was prepared and screened for phytoconstituents. In the in vitro test, crude extract and fractions were assessed for antiperoxidative potential in SNP-induced lipid peroxidation (LPO) in rat heart and artery. For in vivo assessment, CMPC (400, 500, and 600 mg/kg bwt) and the fractions (5 and 6 mg/kg bwt) were co-administered with 5 mg/kg SNP to Wistar rats for 7 days. Extent of LPO in the heart and artery and serum activities of aspartate transaminase (AST) and alanine transaminase (ALT) as well as concentrations of bilirubin, creatinine, urea, and uric acid were evaluated. The result of phytochemical screening revealed the presence of alkaloids, tannins, saponins, flavonoids, terpenoids, phlobatannins, and cardiac glycosides. SNP toxicity significantly (p < 0.05) increased LPO, bilirubin, creatinine, urea, and uric acid levels as well as the activities of AST and ALT. However, the extracts reversed the effect of SNP toxicity. The study revealed the protective effect of P. curatellifolia against SNP-induced cardiovascular toxicity in rats. The study plant could serve as a good therapeutic agent to combat cardiovascular-related complications.

In Vitro Evaluation of Free Radical Scavenging, Fe2+ and SNP-Induced Lipid Peroxidation (Rat Brain) Activities of Methanolic Extracts from Three (3) Northern Nigerian Plants Leaf

Over the years research findings have shown that free radicals are the basis for many diseases. This study sought to investigate the free radical scavenging and inhibition of lipid peroxidation activities of some three Northern Nigerian plant leaf; Boswellia dalzielii Hutch. (Burseraceae) (BDL), Detarium microcarpum Guill. and Perr. (DML), and Daniellia oliveiri (Rolfe) Hutch. & Dalz (DOL). The study investigated both qualitative and quantitative phytochemical screening, free radical scavenging activities of 1, 1-diphenyl–2-picrylhydrazyl DPPH, total antioxidant capacity ABTS, hydroxyl, reducing property and inhibition of lipid peroxidation. All the seven phytochemicals screened were all present in both BDL and DML plant extracts but saponins and glycosides were absent in DOL plant leaf. The result revealed that BDL methanolic extract had the highest total flavonoid and phenolic content while BDL methanolic extract had the highest alkaloid content. DOL methanolic extract had the least content in all the 3 phytochemicals quantified. BDL methanolic extract had the highest free radical scavenging activity in 1, 1-diphenyl–2-picrylhydrazyl (DPPH), Hydroxyl and reducing power assays. While DML methanolic extract, had the highest free radical scavenging ability in 2, 2-azino-bis(3-ethylbenzazoline-6-sulphonic acid (TEAC) assays. The IC 50 of BDL extract (12.37 mg/mL) was not significantly different (p > 0.05) from DML extract (10.39 mg/mL) in the Fe 2+ -induced lipid peroxidation assay. While, the IC 50 of DML extract (14.83 mg/mL) was significantly higher (p < 0.05) than the BDL extract (19.92 mg/mL) in the SNP-induced lipid peroxidation. The DOL extract had the least scavenging and peroxidative inhibitory activity in all the assays carried out. We therefore concluded that the synergistic free radical scavenging activities and inhibition of lipid peroxidation of the three plants studied (especially, BDL and DML), provides a biochemical rationale for their usage as a medicinal plant.

African crocus (Curculigo pilosa) and wonderful kola (Buchholzia coriacea) seeds modulate critical enzymes relevant to erectile dysfunction and oxidative stress.

Background The seeds of African crocus (AC) (Curculigo pilosa) and wonderful kola (WK) (Buchholzia coriacea) are commonly used in folklore medicine in managing erectile dysfunction (ED) without the full understanding of the possible mechanism of actions. This study investigated and compared the effects of aqueous extracts from the seeds of AC and WK on arginase and acetylcholinesterase (AChE) activities and some pro-oxidant [FeSO4 and sodium nitroprusside (SNP)]-induced lipid peroxidation in rat penile homogenate in vitro. Method Aqueous extracts of AC and WK were prepared, and their effects on arginase and AChE activities as well as FeSO4- and SNP-induced lipid peroxidation in rat penile homogenate were assessed. Furthermore, phenolic constituents of the extract were determined using high-performance liquid chromatography coupled with diode-array detector (HPLC-DAD). Results Both extracts exhibited concentration-dependent inhibition on arginase (AC, IC50=0.05 mg/mL; WK, IC50=0.22 mg/mL) and AChE (AC, IC50=0.68 mg/mL; WK, IC50=0.28 mg/mL) activities. The extracts also inhibited FeSO4- and SNP-induced lipid peroxidation in rat penile homogenate. HPLC-DAD analysis revealed the presence of phenolic acids (gallic, caffeic, ellagic and coumaric acids) and flavonoids (catechin, quercetin and apigenin) in AC and WK. AC had higher arginase inhibitory and antioxidative activities but lower AChE inhibitory properties when compared with WK. Conclusions These effects could explain the possible mechanistic actions of the seeds in the management/treatment of ED and could be as a result of individual and/or synergistic effect of the constituent phenolic compounds of the seeds.

Quercetin, rutin, and their combinations modulate penile phosphodiesterase-5′, arginase, acetylcholinesterase, and angiotensin-I-converting enzyme activities: a comparative study

This study demonstrates the effects of rutin and quercetin and their various combinations on phosphodiesterase-5 (PDE-5), arginase, acetylcholinesterase (AChE), and angiotensin-I-converting enzyme (ACE) activities in vitro. The effects of the flavonoids against Fe2+- and sodium nitroprusside (SNP)-induced lipid peroxidation in rats’ corpus cavernosum tissues were also investigated. Quercetin and rutin were dissolved in dimethylsulfoxide (DMSO) to a final concentration of 1 mM each. Thereafter, their combinations (50% quercetin + 50% rutin [Q1:R1]; 75% quercetin + 25% rutin [Q3:R1]; 25% quercetin + 75% rutin [Q1:R3]) were prepared. Our findings revealed that both flavonoids inhibited PDE-5, arginase, AChE, and ACE activities. Rutin exhibited significantly higher inhibitory effects on PDE-5, AChE, and ACE activities compared to quercetin. Considering the combinations, Q1:R3 was more potent compared to Q1:R1 and Q3:R1. Both flavonoids inhibited Fe2+- and SNP-induced lipid peroxidation in rat’s corpus cavernosa tissues. Rutin also showed higher inhibitory effects on Fe- and SNP-induced lipid peroxidation. Similarly, the combinatorial effects of the flavonoids revealed that Q1:R3 significantly inhibited malondialdehyde (MDA) production compared to Q1:R1 and Q3:R1. In conclusion, our findings suggest that the combination of quercetin and rutin is more potent than their individual effect.

Effect of Different Processing Methods on Antihypertensive Property and Antioxidant Activity of Sandpaper Leaf (Ficus exasperata) Extracts

ABSTRACTSandpaper leaf (Ficus exasperata) is commonly used in folk medicine to manage high blood pressure. However, different methods such as soaking, boiling, hand maceration, and blending have been employed for preparing sandpaper leaf extracts for hypertensive patients. This study sought to investigate and compare the influence of different processing methods on the antihypertensive properties of sandpaper leaf as well as its effect on Fe2+ and sodium nitroprusside– (SNP-) induced lipid peroxidation in rat heart in vitro. Sandpaper leaf extracts were prepared using different methods and the resulting solutions were freeze-dried. Effect of the extracts on angiotensin-1-converting enzymes (ACE) and arginase activity was assessed. Thereafter, antioxidant activities of the extracts were determined using in vitro antioxidant assays, and the total phenolic content and flavonoid content of the extracts were determined. The results revealed that sandpaper leaf extracts from different processing methods inhibited ACE and arginase activity in a dose-dependent manner. However, the soaking method had significantly (p < .05) higher inhibitory effect on angiotensin converting (ACE) and arginase activity than hand maceration, boiling, and blending methods. Sandpaper leaf extracts also exhibited high antioxidant activities as typified by their iron-chelating ability, 2, 2′-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical–scavenging and iron-chelating ability as well as inhibition of Fe2+- and SNP-induced lipid peroxidation in rat heart in vitro. Processing methods alter the inhibitory effect of sandpaper leaf extracts on ACE and arginase activities. Thus, inhibition of ACE and arginase coupled with antioxidant properties could offer protective mechanisms against hypertension. However, the soaking method appears to be the most promising among methods considered.

Modulatory effect of caffeic acid on cholinesterases inhibitory properties of donepezil.

Background Donepezil hydrochloride commonly used in the management of Alzheimer's disease (AD), exhibiting its inhibitory effects on acetylcholinesterase and butyrylcholinesterase activity thereby enhance cognitive function. Caffeic acid member of hydroxycinnamic acid is widely present in human diet. This study aims to investigate influence of caffeic acid on acetylcholinesterase and butyrylcholinesterase inhibitory properties of donepezil (in vitro). Methods 5 mg of donepezil was dissolved in 50 mL distilled water while 10 mg of caffeic acid was dissolved in 100 mL distilled water. Therefore, mixtures of samples were prepared as follows: A2=donepezil 0.075 mg/mL+caffeic acid 0.025 mg/mL; A3=donepezil 0.050 mg/mL+caffeic acid 0.050 mg/mL; A4=donepezil 0.025 mg/mL+caffeic acid 0.075 mg/mL. All samples were kept in the refrigerator at 4 °C for subsequent analysis. Results The result showed that all the combinations show an inhibitory effect on acetylcholinesterase and butyrylcholinesterase activity in vitro, with the combination A4=donepezil 0.025 mg/mL+caffeic acid 0.075 mg/mL had significant (p<0.05) highest inhibitory effect on acetylcholinesterase and butyrylcholinesterase activity in vitro. More so, all the samples were able to prevent pro-oxidants (FeSO4 and sodium nitroprusside [SNP] ) induced lipid peroxidation in rat brain homogenate, with the combination A4=donepezil 0.025 mg/mL+caffeic acid 0.075 mg/mL and A3=donepezil 0.050 mg/mL+caffeic acid 0.050 mg/mL had highest inhibitory effect against FeSO4 and SNP induced lipid peroxidation in rat brain homogenate in vitro respectively. Moreover, all the samples exhibit antioxidant properties as typified by their ability to chelate iron (II) ion (Fe2+), hydroxyl radical (OH٭) radical scavenging ability and ferric reducing property (FRAP). Conclusions Therefore, the combination of caffeic acid with donepezil enhances the antioxidant properties of donepezil. The combination of caffeic acid with donepezil could be a therapeutic aid in the management of AD, possibly with fewer side effects of donepezil. Nevertheless, the combination donepezil 0.025 mg/mL+caffeic acid 0.075 mg/mL acid look promising.

Modulatory effects of Aqueous extract from Tetracarpidium conophorum leaves on key enzymes linked to erectile dysfunction and oxidative stress-induced lipid peroxidation in penile and testicular tissues

Tetracarpidium conophorum (walnut) is used in folk medicine for the treatment of erectile dysfunction but the mechanism remains unclear. This study evaluated the effect of aqueous extract from T conophorum leaves on oxidative stress-induced penile damage and key enzymes linked to erectile dysfunction. The inhibitory effect of the extract on sodium nitroprusside (SNP)-induced lipid peroxidation, arginase, angiotensin I-converting enzyme (ACE) and acetylcholinesterase (AChE) activities in penile and testicular tissue homogenates were determined via colorimetric method. The aqueous extract inhibited SNP-induced lipid peroxidation in rats penile and testicular homogenates in a dose dependent manner. The highest inhibitory effect was obtained in the penis at a concentration of 0.5 mg/mL. Furthermore, the extract inhibited arginase activity in a dose dependent pattern. The IC50 revealed that the extract had significantly (P

EXTRACTS OF OCIMUM GRATISSIMUM LEAVES INHIBITS FE2+ AND SODIUM NITROPRUSSIDE INDUCED OXIDATIVE STRESS IN RAT LIVER

This study investigate the antioxidative properties and the ability of aqueous, ethanol and ethyl acetate extracts from Ocimum gratissimum (OG) leaves to inhibit some pro-oxidants (Fe and sodium nitroprusside) induced lipid peroxidation in rat’s liver homogenates in vitro. The ability of the extracts to inhibit 25 μM FeSO4 and 7.0 μM sodium nitroprusside induced lipid peroxidation in isolated rat’s liver was determined. The results of the study revealed that both pro-oxidants caused a significantly decrease in (p<0.05) accumulation of lipid peroxides. However, aqueous extract of Ocimum gratissimum shows a high ability to inhibit lipid production in the liver induced with SNP than Fe. Ethanol and ethyl acetate extract of Ocimum gratissimum which shows a high ability to inhibit lipid production more when induced with Fe than SNP. However, ethyl acetate fraction of Ocimum gratissimum shows a higher inhibitory effect on both Fe and SNP induced lipid peroxidation in rat’s liver. This might be as a result of its significantly higher extractable phytochemicals. Therefore, Fe II and sodium nitroprusside induced oxidative stress could be managed by dietary intake of Ocimum gratissimum leaves.

Protective effect of phenolic extracts from two species of miracle berry leaves (Thaumatococcus daniellii and Megaphrynium macrostachyum) on some pro-oxidant induced oxidative stress in rat pancreas in vitro.

Traditionally, miracle berry leaves are mostly used as food wrappers in order to increase the shelf life of the food. Therefore, this study sought to investigate the antioxidative properties and protective effect of phenolic extracts from two species of miracle berry leaves namely; Thaumatococcus daniellii (Benn) Benth and Megaphrynium macrostachyum (Benth) Milne-Redh on some pro-oxidant induced oxidative stress in rat pancreas in vitro. The phenolic extract was prepared with 80% acetone (v/v); thereafter, ability of the extracts to inhibit some prooxidants (FeSO4 and Sodium nitroprusside, SNP) induced lipid peroxidation in rat’s pancreas was assessed. Furthermore, antioxidative properties of the phenolic extracts were evaluated. The result revealed that both leaves extracts inhibit Fe 2+ and SNP-induced lipid peroxidation on rat’s pancreas in a dose dependent manner (0 – 0.5 mg/mL) and also exhibit antioxidant properties as typified by their Fe 2+ chelating, DPPH and OH radical scavenging abilities, however, M. macrostachyum leaf had a significantly (P<0.05) higher Fe 2+ and SNP-induced lipid peroxidation on rat’s pancreas and antioxidant properties than T. daniellii leaf in vitro. The inhibition of Fe 2+ and SNP-induced lipid peroxidation in rat’s pancreas by both leaves could be attributed to their reducing power, chelating and radical scavenging abilities. Therefore, this antioxidative potential of both M. macrostachyum and T. daniellii leaves clearly gives us an insight that they could be used to prevent degenerative disease associated with oxidative stress. Hence, this antioxidant effect could be some possible mechanism by which they are used as food wrappers in order to increase the shelf life of food.

Biological activities, antioxidant properties and phytoconstituents of essential oil from sweet basil (Ocimum basilicum L.) leaves

This study investigated the biological activities of essential oil from sweet basil leaves via its effect on α-amylase, α-glucosidase and angiotensin-I-converting enzyme (ACE) activities, inhibition of Fe2+ and sodium nitroprusside (SNP)-induced lipid peroxidation in rats’ pancreas and heart homogenates. The phytoconstituents of the oil were analysed using gas chromatography (GC). The essential oil exhibited a dose-dependent inhibition of α-amylase (IC50 = 3.21 mg/mL), α-glucosidase (IC50 = 3.06 mg/mL) and ACE (IC50 = 0.89 mg/mL) activities in vitro. The oil also inhibited both Fe2+- and SNP-induced lipid peroxidation in rats’ pancreas and heart. The GC analysis revealed the presence of about 28 phytoconstituents, with limonene (47.40 %), borneol (8.66 %), geranial (6.93 %), neral (5.71 %), myrcene (4.68 %), β-caryophyllene (4.68 %), α-terpineol (4.60 %), 1,8-cineole (4.17 %), linalool (3.53 %), β-elemene (3.05 %), germacrene D (2.68 %), and terpinen-4-ol (2.21 %) being the most prominent. Thus, the antioxidant and enzyme inhibitory effects of the essential oil could be attributed to the presence of these phytochemicals, which could be the principle responsible for the antidiabetic and antihypertensive properties of the essential oil. This study therefore, could provide the possible rationale for the application of essential oil from sweet basil leaves as functional foods and nutraceutical ingredient in the management of type 2 diabetes and hypertension.

Inhibition of key enzymes linked to type 2 diabetes and sodium nitroprusside-induced lipid peroxidation in rat pancreas by water-extractable phytochemicals from unripe pawpaw fruit (Carica papaya)

Various parts of unripe pawpaw (Carica papaya Linn) fruit have been reportedly used for the management or treatment of diabetes mellitus in folklore medicine. Therefore, the present study sought to investigate the inhibitory effects of the aqueous extract of different parts of unripe pawpaw fruit on key enzymes linked to type 2 diabetes (α-amylase and α-glucosidase) and sodium nitroprusside (SNP)-induced lipid peroxidation in rat pancreas in vitro. The aqueous extracts of the unripe pawpaw (C. papaya) fruit parts were prepared (1:20 w/v) and the ability of the extracts to inhibit α-amylase, α-glucosidase and SNP-induced lipid peroxidation in rat pancreas in vitro was investigated. The results revealed that all the extracts inhibited α-amylase (IC50=0.87-1.11 mg/mL), α-glucosidase (IC50=1.76-2.64 mg/mL) and SNP-induced lipid peroxidation (IC50=1.99-2.42 mg/mL) in a dose-dependent manner. However, combination of the flesh, seed and peel in equal amounts had the highest inhibitory effect on α-amylase and α-glucosidase activities. Strong inhibitory activities of the unripe pawpaw fruit against key enzymes linked to type 2 diabetes and SNP-induced lipid peroxidation in rat pancreas could be part of the mechanism by which unripe pawpaw is used in the management/prevention of diabetes mellitus in folk medicine. However, combining the unripe pawpaw fruit parts in equal amounts exhibited synergistic properties on α-amylase and α-glucosidase inhibitory activities.

Inhibition of key enzymes linked to type 2 diabetes and sodium nitroprusside-induced lipid peroxidation in rat pancreas by water extractable phytochemicals from some tropical spices

Context: Spices have been used as food adjuncts and in folklore for ages. Inhibition of key enzymes (α-amylase and α-glucosidase) involved in the digestion of starch and protection against free radicals and lipid peroxidation in pancreas could be part of the therapeutic approach towards the management of hyperglycemia and dietary phenolics have shown promising potentials.Objective: This study investigated and compared the inhibitory properties of aqueous extracts of some tropical spices: Xylopia aethiopica [Dun.] A. Rich (Annonaceae), Monodora myristica (Gaertn.) Dunal (Annonaceae), Syzygium aromaticum [L.] Merr. et Perry (Myrtaceae), Piper guineense Schumach. et Thonn (Piperaceae), Aframomum danielli K. Schum (Zingiberaceae) and Aframomum melegueta (Rosc.) K. Schum (Zingiberaceae) against α-amylase, α-glucosidase, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and sodium nitroprusside (SNP)-induced lipid peroxidation in rat pancreas - in vitro using different spectrophotometric method.Materials and methods: Aqueous extract of the spices was prepared and the ability of the spice extracts to inhibit α-amylase, α-glucosidase, DPPH radicals and SNP-induced lipid peroxidation in rat pancreas - in vitro was investigated using various spectrophotometric methods.Result: All the spice extracts inhibited α-amylase (IC50 = 2.81–4.83 mg/mL), α-glucosidase (IC50 = 2.02–3.52 mg/mL), DPPH radicals (EC50 = 15.47–17.38 mg/mL) and SNP-induced lipid peroxidation (14.17–94.38%), with the highest α-amylase & α-glucosidase inhibitory actions and DPPH radical scavenging ability exhibited by X. aethiopica, A. danielli and S. aromaticum, respectively. Also, the spices possess high total phenol (0.88–1.3 mg/mL) and flavonoid (0.24–0.52 mg/mL) contents with A. melegueta having the highest total phenolic and flavonoid contents.Discussion and conclusion: The inhibitory effects of the spice extracts on α-amylase, α-glucosidase, DPPH radicals and SNP-induced lipid peroxidation in pancreas (in vitro) could be attributed to the presence of biologically active phytochemicals such as phenolics and some non-phenolic constituents of the spices. Furthermore, these spices may exert their anti-diabetic properties through the mechanism of enzyme inhibition, free radicals scavenging ability and prevention of lipid peroxidation.

Antioxidant effect of functionalized alkyl-organotellurides: a study in vitro

We evaluated the in vitro antioxidant effect of alkyl-organotellurides A–D on lipid peroxidation and protein carbonylation in rat liver homogenates. The thiol oxidase and thiol peroxidase-like activities of compounds were investigated. δ-Aminolevulinic acid dehydratase (δ-ALA-D) activity was determined in rat liver homogenates. Compounds A–D protected against lipid peroxidation induced by Fe2+/EDTA and sodium nitroprusside (SNP). According to the confidence limits of the IC50 values of compounds A–D, the IC50 values for organotellurides followed the order: C (0.30 µM) ≤ B (0.40 µM) < D (0.68 µM) < A (2.90 µM), for Fe2+/EDTA, and B (0.21 µM) ≤ C (0.33 µM) ≤ D (0.43 µM) < A (1.21 µM) for SNP-induced lipid peroxidation. Compounds A–D reduced protein carbonyl content to control levels. The results demonstrated an inverse correlation between thiol oxidase and δ-ALA-D activities. This study supports an antioxidant effect of organotellurides A–D on rat liver.

Involvement of nitric oxide in nitroprusside-induced hepatocyte cytotoxicity

Sodium nitroprusside (SNP) cytotoxicity towards rat hepatocytes was accompanied by peroxynitrite formation, lipid peroxidation, inhibition of glycolysis, cyanide (CN) release, partial inhibition of hepatocyte respiration, and ATP depletion. Antioxidants and desferoxamine prevented both cytotoxicity and lipid peroxidation induced by SNP. The CN antidote thiosulfate or the CN trapping agents dihydroxyacetone and glyceraldehyde increased SNP metabolism, SNP-induced peroxynitrite formation, cytotoxicity, and lipid peroxidation. On the other hand, addition of non-toxic concentrations of CN to hepatocytes prevented SNP metabolism and SNP-induced lipid peroxidation and cytotoxicity. SNP depleted hepatocyte GSH immediately upon addition, and GSH-depleted hepatocytes were more susceptible to SNP. The results of this study suggest that nitric oxide rather than CN mediates SNP cytotoxicity in isolated cells.