A Fluorescence Ratiometric Probe for Cysteine/Homocysteine and Its Application for Living Cell Imaging

A fluorescence ratiometric probe 1 for cysteine (Cys) and homocysteine (Hcy) has been rationally constructed based on intramolecular charge transfer (ICT) mechanism. Upon treatment with Cys/Hcy, probe 1 exhibited a fluorescence ratiometric response, with the emission wavelength displaying a large shift (from 526 nm to 446 nm). When 90 μM Cys were added, the emission ratios (I446/I526) of the probe changed dramatically from 0.01797 to 4.65472. The detection limit was also measured to be 0.18 μM (S/N = 3). The theoretical calculations have confirmed that the ratiometric response of probe 1 to Cys/Hcy is due to the inhibition of ICT process upon the reaction of probe 1 with Cys/Hcy. Furthermore, the fluorescence imaging experiments in living cell demonstrated that probe 1 was favourable for intracellular Cys/Hcy imaging.

Homocysteine as a Biomarker for Predicting Disease-Free Survival in Breast Cancer

Introduction: Breast cancer is the leading cause of cancer mortality among women. Some biomarkers and clinical features are used for the diagnosis and prognosis of this tumor, but no prognostic or predictive marker is routinely available specifically for hormone receptor positive tumors. Homocysteine is well known as a risk factor in atherosclerotic vascular diseases, but its participation in cancer biology is still unclear. The aim of this study was to evaluate serum Homocysteine and Cysteine as biomarkers of disease progression in breast tumor. As a secondary objective, the effect of a short course (one month) of hormonal treatment on Homocysteine, Cysteine and DNA methylation levels was also evaluated. Methods: Blood samples, tumor samples and normal adjacent tissue were collected during the initial biopsy (pre-treatment) and after one month of hormonal therapy (post-treatment). Serum Homocysteine and Cysteine were analyzed by HPLC and tissue global DNA methylation was determined by the Methylation-Sensitive Restriction Enzyme (MSRE) technique. Results: Variations in Homocysteine levels were significantly correlated with Disease-Free Survival. Cox proportional risk model demonstrated that nodal status and Homocysteine levels were independent prognostic factors for disease-free survival (DFS). A significant difference was observed between pre-and post-treatment levels of Homocysteine and Cysteine in advanced tumors, suggesting a prognostic role in patients with poor clinical characteristics. Conclusion: Although more studies are needed to confirm these results, our research suggests that Hcy might be used as a prognostic biomarker for breast cancer.

Synergistic effects of elevated homocysteine level and abnormal blood lipids on the onset of stroke

Hyperhomocysteinemia and abnormal blood lipids are independent risk factors for stroke. However, whether both factors exert a synergistic effect in the onset of stroke remains unclear. The present study is a retrospective analysJs of 2 089 cases of stroke and 2 089 control cases of simple in- tervertebral disk protrusion using a paired multivariate logistic regression method. Adjusting for known confounding variables including the patients＇ age, gender, smoking status, alcohol con- sumption status, patient and family medical history, and clinical biochemical indices, elevated ho- mocysteine level was related to the onset of stroke. Patients with elevated homocysteJne levels and abnormal blood lipids showed a 40.9 % increase in the risk for stroke compared to patients with normal homocysteine levels and blood lipids （odds ratio 1.409; 95% confidence interval 1.127-1.761）. These results indicate that elevated homocysteine and abnormal blood lipids exert synergistic effects in the onset of stroke. Patients with elevated homocysteine levels and abnormal blood lipids are predisposed to stroke.

Cytoprotective effects of amifostine,ascorbic acid and N-acetylcysteine against methotrexate-induced hepatotoxicity in rats

AIM:To investigate the potential role of oxidative stress and the possible therapeutic effects of N-acetyl cysteine(NAC),amifostine(AMF)and ascorbic acid(ASC)in methotrexate(MTX)-induced hepatotoxicity.METHODS:An MTX-induced hepatotoxicity model was established in 44 male Sprague Dawley rats by administration of a single intraperitoneal injection of20 mg/kg MTX.Eleven of the rats were left untreated(Model group;n=11),and the remaining rats were treated with a 7-d course of 50 mg/kg per day NAC (MTX+NAC group;n=11),50 mg/kg per single dose AMF(MTX+AMF group;n=11),or 10 mg/kg per day ASC(MTX+ASC group;n=11).Eleven rats that received no MTX and no treatments served as the negative control group.Structural and functional changes related to MTX-and the various treatments were assessed by histopathological analysis of liver tissues and biochemical assays of malondialdehyde(MDA),superoxide dismutase(SOD),catalase,glutathione(GSH)and xanthine oxidase activities and of serum levels of aspartate aminotransferase,alanine aminotransferase,alkaline phosphatase and total bilirubin.RESULTS:Exposure to MTX caused structural and functional hepatotoxicity,as evidenced by significantly worse histopathological scores[median(range)injury score:control group:1(0-3)vs 7(6-9),P=0.001]and significantly higher MDA activity[409(352-466)nmol/g vs 455.5(419-516)nmol/g,P<0.05].The extent of MTX-induced perturbation of both parameters was reduced by all three cytoprotective agents,but only the reduction in hepatotoxicity scores reached statistical significance[4(3-6)for NAC,4.5(3-5)for AMF and 6(5-6)for ASC;P=0.001,P=0.001 and P<0.005vs model group respectively].Exposure to MTX also caused a significant reduction in the activities of GSH and SOD antioxidants in liver tissues[control group:3.02(2.85-3.43)μmol/g and 71.78(61.88-97.81)U/g vs model group:2.52(2.07-3.34)μmol/g and 61.46(58.27-67.75)U/g,P<0.05];however,only the NAC treatment provided significant increases in these antioxidant enzyme activities[3.22(2.54-3.62)μmol/g and 69.22(61.13-100.88)U/g,P<0.05 and P<0.01vs model group respectively].CONCLUSION:MTX-induced structural and functional damage to hepatic tissues in rats may involve oxidative stress,and cytoprotective agents(NAC>AMF>ASC)may alleviate MTX hepatotoxicity.

Aberrant methylation of secreted protein acidic and rich in cysteine gene and its significance in gastric cancer

BACKGROUND Aberrant methylation in DNA regulatory regions could downregulate tumor suppressor genes without changing the sequences.However,our knowledge of secreted protein acidic and rich in cysteine(SPARC)and its aberrant methylation in gastric cancer(GC)is still inadequate.In the present research,we performed fundamental research to clarify the precise function of methylation on SPARC and its significance in GC.AIM To investigate promoter methylation and the effects of the SPARC gene in GC cells and tissues and to evaluate its clinical significance.METHODS Plasmids that overexpressed the SPARC gene were transfected into human GC BGC-823 cells;non-transfected cells were used as a control group(NC group).Quantitative real-time polymerase chain reaction and western blotting(WB)were then used to detect the expression of SPARC.Methylation-specific polymerase chain reaction was executed to analyze the gene promoter methylation status.Cell viability was measured by the cell counting kit-8 assay.The migration and invasion ability of cells were detected by scratch assays and transwell chamber assays,respectively.Cell cycle events and apoptosis were observed with a flow cytometer.RESULTS The expression of SPARC mRNA in GC tissues and cells was significantly lower and showed differing degrees of hypermethylation,respectively,than that in normal adjacent tissues and control cells.Treatment with 5-Aza-2’-deoxycytidine(5-Aza-Cdr)was able to restore the expression of SPARC and reverse promoter hypermethylation.Overexpression of the SPARC gene significantly inhibited proliferation,migration,and invasion of GC cells,while also causing cell cycle arrest and apoptosis;the NC group exhibited the opposite effects.CONCLUSION This study demonstrated that SPARC could function as a tumor suppressor and might be silenced by promoter hypermethylation.Furthermore,in GC cells,SPARC inhibited migration,invasion,and proliferation,caused cell cycle arrest at the G0/G1 phase,and promoted apoptosis.

Flow-injection Determination of Cysteine,N-Acetyl Cysteine and Glutathione in Pharmaceuticals via Potassium Ferricyanide-Fe(Ⅲ) Spectrophotometric System

A simple flow injection spectrophotometric method is reported for the determination of cysteine,N-acetyl cysteine and glutathione based on the reduction of Fe（Ⅲ）/ferricyanide,the in situ reduced ions are reacted with unreduced portion of ferricyanide/Fe（Ⅲ） to form soluble Prussian blue,which is monitored at 735 nm.The calibration graphs are linear in the concentration ranges of（1―100）×10-6 mol/L for cysteine and N-acetyl cysteine,and（1―50）×10-6 mol/L for glutathione.The relative standard deviations of 1.8%,2.5% and 1.9% were found for eleven replicate analyses of 5×10-6 mol/L cysteine,N-acetyl cysteine and glutathione.The limits of detection（3σ blank） at 5×10-7 mol/L for cysteine,and 3×10-7 mol/L for N-acetyl cysteine and glutathione were obtained.The proposed method allowed 60 injections/h.The effects of common substances present in pharmaceuticals and human physiological fluids were examined.The method was applied to determining cysteine in pharmaceutical formulations with the recoveries in a range of 97% to 106% and the results obtained are agreed well with labeled values.

Assay of Cysteine in Human Serum with Quinine-Ce^(4+) Chemiluminescence System

A sensitive and selective chemiluminescence (CL) method was developed for the determination of cysteine. This method is based on that the weak CL of cysteine oxidized with cerium (IV) can be greatly enhanced by quinine, and the total cysteine in human serum can be detected through simply diluting with water, showing a simpler analytical characteristic.

Characterization of Cysteine Coated Magnetite Nanoparticles as MRI Contrast Agent

In this work,a kind of stabilized ferrofluid based on magnetite nanoparticles(mean core and its coating size about 21.9 and 1.6 nm,respectively)was synthesized via coprecipitation method.Cysteine was used as surfactant due to its proper conjunction to the surface of magnetite nanoparticles.Coating density and synthesized ferrofluids were characterized by using transmission electron microscope,thermogravimetry analysis,dynamic light scattering and fourier transform infrared spectroscopy techniques.Magnetic resonance imaging studies show that the synthesized ferrofluid can be used as a potential contrast enhancement agent especially for imaging lymphatic system.

An Elevated Dietary Cysteine to Methionine Ratio Does Not Impact on Dietary Methionine Efficiency and the Derived Optimal Methionine to Lysine Ratio in Diets for Meat Type Chicken

Optimal dietary methionine (Met) to lysine (Lys) ratio in presence of elevated dietary cysteine (Cys) levels was derived for meat type growing chicken. Twelve averaged weighed Ross 308 birds (each 50% of male and female per dietary treatment) were utilized in N balance trials. During starter (d10 - 20) and grower period (d25 - 35) five dietary treatments were used. Diets based on uniform mixtures of maize, wheat, soybean meal, potato protein and fish meal were supplemented with crystalline amino acids (AA). In diets 1 - 3, the dietary Cys to Met ratio was set as 85, 95 and 105 to 100, respectively. Diet 4, at a Cys to Met ratio of 105 to 100, was additionally supplemented with betaine (BET) as methyl group donor. Diets 1 - 4 were limiting in Met, diet 5 without L-Lys·HCl addition was limiting in Lys. Individual N-balance data per treatment were utilized for assessing protein quality and efficiency of dietary Met (Diets 1 - 4) or Lys (Diet 5) based on “Goettingen approach”. Elevated dietary Cys supply and supplemented BET failed to improve both dietary protein quality and Met efficiency. The established optimal Met to Lys ratio was on average 34 to 100 for growing chicken during starter and grower period, respectively.

Contribution of lysosomal cysteine proteases in cardiac and renal diseases

Cardiac and renal diseases(CRDs) are characterized by extensive remodeling of the extracellular matrix(ECM)architecture of the cardiorenal system. Among the many extracellular proteolytic enzymes present in cardiorenal cells and involved in ECM remodeling, members of the matrix metalloproteinase family and serine protease family have received the most attention. However, recent findings from laboratory and clinical studies have indicated that cysteine protease cathepsins also participate in pathogenesis of the heart and kidney.Deficiency and pharmacological inhibition of cathepsins have allowed their in vivo evaluation in the setting of pathological conditions. Furthermore, recent studiesevaluating the feasibility of cathepsins as a diagnostic tool have suggested that the serum levels of cathepsins L, S and K and their endogenous inhibitor cystatin C have predictive value as biomarkers in patients with coronary artery disease and heart and renal failure. The goal of this review is to highlight recent discoveries regarding the contributions of cathepsins in CRDs, particularly hypertensive heart failure and proteinuric kidney disease.

The Construct of A Neutral Medium Applicable Electrochemiluminescent Sensor Based on the Chemical Modification of Cysteine and Luminol

In the phosphate buffer solution of pH＞7,the cysteine sensitized the electrochemiluminescence (ECL) of luminol.It could be modified on the surface of platinum electrode and furthermore adsorbing the luminol on its exterior to construct an ECL sensor.The ECL intensity of this sensor was strong enough and very stable.There wasn't obvious decrease of ECL intensity for thirty times of using in 48 hours with the relative standard deviation (RSD) of 0.98%.It could be used to determine some quenching effective molecules such as superoxide dismutase (SOD) with negative response upon the concentration range from 4.8 IU/ml to 57.6 IU/ml.

Protective effect of Scrophularia striata combined with trehalose and cysteine added to diluents on cryopreservd goat epididymal sperm

Objective:To evaluate antioxidant effects of Scrophularia(S.)striata ethanol extract,trehalose and cysteine added to diluents on cryopreserved goat epididymal sperms.Methods:Motility and standard motion parameters of sperm were assessed by using computer assisted sperm motility analysis system.Sperm viability was evaluated by eosin-nigrosin staining method.Hypo-osmotic swelling test was used to evaluate membrane health.Thiobarbituric acid testing was used to measure malondialdehyde(MDA)concentrations.To assess DNA fragmentation,sperm chromatin dispersion test was used.In Experiment 1,treatments consisting of basal Tris diluent supplemented with 25,50 or 100µg/mL of S.striata ethanol extract gave the best concentration to the freezing diluents.Experiment 2 was carried out to compare the best concentration of S.striata ethanol extract(50µg/mL)resulting from the first experiment with 150 mM trehalose and/or 5 mM cysteine alone or in combination.Results:S.striata ethanol extract(50µg/mL)significantly increased sperm viability,motility and progressive motility and at the same time decreased MDA concentration and DNA fragmentation compared to other treatments(P<0.05).In addition,all treatment groups resulted in viability,membrane health,total motility,progressive motility,curvilinear velocity,straightline velocity higher and MDA lower compared to the control group(P<0.05).Acrosome integrity was significantly higher in 50µg/mL of S.striata ethanol extract combined with cysteine,trehalose,or cysteine+trehalose groups than those in the control,trehalose,cysteine,and 50µg/mL of S.striata ethanol extract groups(P<0.05).Regarding DNA,extenders supplemented with 50µg/mL of S.striata ethanol extract,50µg/mL of S.striata ethanol extract+trehalose,and 50µg/mL of S.striata ethanol extract+trehalose+cysteine were superior to other treatments.Conclusions:Adding 50µg/mL of S.striata ethanol extract alone or in combination with trehalose and cysteine can improve the quality of cryopreserved epididymal sperms of goats.

Study on Cobalt(Ⅱ)Ionprobe for Cysteine Determination

A spectrophotometric method for the determination of cysteine was developed basing on the reaction of cysteine with cobalt (Ⅱ) in NH 4Cl NH 4OH. The molar absorptivity is 7.98×10 3 L·mol -1 ·cm -1 at 284 nm. Beer′s law is obeyed for cysteine in the range of 0～2.0×10 -4 mol·L -1 . The method was applied to the assay of cysteine in urine.

Synthesis of N1-Substituted-3-aryl-4-alkyl-4, 5-dihydro-1H-1-pyra-zolethiocarboxamide as Novel Small Molecule Inhibitors of Cysteine Protease of T.cruzi

A series of N1-substituted-3-aryl-4-alkyl-4, 5-dihydro-1H-1-pyrazolethiocarboxamide were prepared from the Mannich bases of aryl ketones in good yields. Some derivatives were found to be active against the cysteine protease of T.cruzi..

Diagnostic and prognostic value of secreted protein acidic and rich in cysteine in the diffuse large B-cell lymphoma

BACKGROUND Secreted protein acidic and rich in cysteine(SPARC)is an extracellular matrixassociated protein.Studies have revealed that SPARC is involved in the cell interaction and function including proliferation,differentiation,and apoptosis.However,the role of SPARC in cancer is controversial,as it was reported as the promoter or suppressor in different cancers.Further,the role of SPARC in lymphoma is unclear.AIM To identify the expression and significance of SPARC in lymphoma,especially in diffuse large B-cell lymphoma(DLBCL).METHODS The expression analysis of SPARC in different cancers was evaluated with Oncomine.The Brune,Eckerle,Piccaluga,Basso,Compagno,Alizadeh,and Rosenwald datasets were included to evaluate the mRNA expression of SPARC in lymphoma.The Cancer Genome Atlas(TCGA)-DLBCL was used to analyze the diagnostic value of SPARC in DLBCL.The Compagno and Brune DLBCL datasets were used for validation.Then,the diagnostic value was evaluated with the receiver operating characteristic(ROC)curve.The Kaplan-Meier plot was conducted with TCGA-DLBCL,and the ROC analysis was performed based on the survival time.Further,the overall survival analysis based on the level of SPARC expression was performed with the GSE4475 and E-TABM-346.The Gene Set Enrichment Analyses(GSEA)was performed to make the underlying mechanism-regulatory networks.RESULTS The pan-cancer analysis of SPARC showed that SPARC was highly expressed in the brain and central nervous system,breast,colon,esophagus,stomach,head and neck,pancreas,and sarcoma,especially in lymphoma.The overexpression of SPARC in lymphoma,especially DLBCL,was confirmed in several datasets.The ROC analysis revealed that SPARC was a valuable diagnostic biomarker.More importantly,compared with DLBCL patients with low SPARC expression,those with higher SPARC expression represented a higher overall survival rate.The ROC analysis showed that SPARC was a favorable prognostic biomarker for DLBCL.Results of the GSEA confirmed that the high expression of SPARC was closely associated with focal adhesion,extracellular matrix receptor interaction,and leukocyte transendothelial migration,which suggested that SPARC may be involved in the regulation of epithelial-mesenchymal transition,KRAS,and myogenesis in DLBCL.CONCLUSION SPARC was highly expressed in DLBCL,and the overexpression of SPARC showed sound diagnostic value.More interestingly,the overexpression of SPARC might be a favorable prognostic biomarker for DLBCL,suggesting that SPARC might be an inducible factor in the development of DLBCL,and inducible SPARC was negative in some oncogenic pathways.All the evidence suggested that inducible SPARC might be a good diagnostic and prognostic biomarker for DLBCL.

Cysteine Supplementation to Parenteral Nutrition Improves Red Blood Cell Glutathione Concentrations of Critically Ill Preterm Neonates

Premature neonates have immature antioxidant enzyme systems rendering them more susceptible to oxidative injury. One key antioxidant is glutathione (GSH). The rate limiting amino acid (AA) in GSH production is thought to be cysteine. Critically ill premature neonates who are parenterally fed are often supplemented with additional cysteine, yet the need for cysteine and optimal dose is unknown. This was a prospective, un-blinded, three-group, randomized crossover study aimed to evaluate three doses of cysteine by analyzing red blood cell (RBC) GSH, plasma AA, weight, and nitrogen balance. Neonates were randomized to receive 72 hours of each of the following cysteine doses: 10 mg/g AA, 20 mg/g AA, and 40 mg/g AA. GSH, plasma AAs, weight, and nitrogen balance were evaluated at baseline (after 72 hours of 0 mg/g AA), day three, day six, and day nine. Sixteen patients completed all doses of cysteine, which resulted in significantly increased RBC GSH concentrations over baseline. Plasma concentrations of cystine, total and free cysteine/cystine, glycine and serine increased with cysteine dose. All cysteine doses were associated with adequate weight gain, and positive nitrogen balance. These results are contrary to more recent studies of cysteine effect on RBC GSH concentrations in preterm neonates and infants, but may reflect the severity of illness in our study subjects, where cysteine requirements may be increased.

Cloning and Sequence Analysis of a Cysteine Proteinase Inhibitor Gene from Seedless Litchi

[Objective] This study aimed to clone and analyze the cysteine proteinase inhibitor gene from seedless litchi. [Method] According to the EST se- quence of cysteine proteinase inhibitor in constructed SSH snhtraetive library of seedless litchi abortion, nucleotide sequence of the cysteine proteinase inhibitor gene was obtained by using RACE technology and analyzed by using bioinformatics software. [ Result ] A cysteine protease inhibitor gene was obtained with the sequence of 635 bp containing a 321 bp open reading frame. It was predicted that the erlcoded protein contained 106 amino acids with conserved domain of cysteine proteinase inhibitor and had relatively high homology with the cysteine proteinase inhibitor gene of several species, [ Conclusion] This study laid the foundation for further ex- ploring the physiological functions of this cysteine proteinase inhibitor gene in plants.

Interactions and Effects on Cysteine Synthase Activity of Aminooxyacetate and Boc-Aminooxyacetate on the Bioherbicides <i>Colletotrichum truncatum</i>and <i>Alternaria cassia</i>and Their Weed Hosts

Aminooxyacetate (AOA) is a pyridoxal phosphate antagonist that inhibits various plant enzymes (including transaminases) which require pyridoxal phosphate as a cofactor and it exhibits phytotoxic and herbicidal properties. We examined AOA and its analog, N-t-butoxycarbonyl-AOA (Boc-AOA) for phytotoxicity, interactions with weed pathogens (bioherbicides), and effects on an important pyridoxal requiring enzyme, cysteine synthase (CS, E.C. 4.2.99.8). Studies were performed on two weeds, i.e., hemp sesbania [Sesbania exaltata (Raf.) Rybd. Ex A.W. Hill] and sicklepod (Senna obtusifolia), and two pathogens, (Colletotrichum truncatum and Alternaria cassiae), that are bioherbicidal agents against hemp sesbania and sicklepod, respectively. Pathogenicity tests, and assays for extractable, and in vitro CS activities were utilized. Phytotoxicity bioassays indicated that the bulky t-butoxycarbonyl moiety substitution on the AOA molecule did not substantially hinder expression of biological activity of Boc-AOA in these tests. Generally, spray application of the compounds to young dark-grown seedlings caused little growth effects, but root-feeding of the chemicals reduced growth (stem elongation) in both weeds. Hemp sesbania was generally more tolerant than sicklepod to these compounds. The only apparent positive interaction of the chemicals with these pathogens was the Boc-AOA: C. truncatum combination treatment on hemp sesbania. Both compounds reduced extractable CS in the seedlings by 30%, 72 h after treatment. CS activity was reduced by 15% in hemp sesbania treated with C. truncatum but increased 20% above control levels after infection of sicklepod by A. cassiae. This latter effect suggests that CS may be involved in sicklepod defense mechanisms against this pathogen.

Macromolecular inhibitors of malarial cysteine proteases —An invited review

There are evidences indicating that cysteine proteases play an essential role in malaria parasites;therefore, an obvious area of investigation is the inhibition of these enzymes to treat malaria. Small cysteine protease inhibitors of malaria are well studied, but macromolecular nature of inhibitor is a new field to explore. In malarial cysteine proteases, there are macromolecular endogenous inhibitors playing important roles in regulation of the cysteine protease activity of parasite and host. Recent studies suggested that there are known and characterized endogenous inhibitors like falstatin present in P. falciparum, PbICP (inhibitor of cysteine protease in P. berghei), PyICP (inhibitor of cysteine protease in P. yoelli), and other macromolecular inhibitors which are the prodomain of enzyme itself regulating the activity of the mature enzyme. All the known macromolecular endogenous inhibitors are using specific loop-like structure to interact with malarial cysteine proteases. The majority of macromolecular inhibitors are competitive in nature, and block access to the active site of their target protease, but do not bind in a strictly substrate-like manner. They rather interact with the protease subsites and catalytic residues in a non-catalytically competent manner. In future, designing inhibitors based on these protein-protein interactions will be a new approach in the field of malaria. Since macromolecular inhibitors can gain potency through the burial of a large surface area and specificity through contacts with secondary binding sites critical for inhibition, and could be less prone to drug resistant mutation.

Reversal Effects of N-Acetyl Cysteine on <i>Moringa oleifera</i>Leaves-Induced Sub-Acute Hepatotoxicity in Wistar Albino Rats

Background: M. oleifera is a highly valued medicinal plant used widely from time immemorial to treat various ailments. However, with continued un-standardized use of the plant leaves, studies have reported organ toxicity to the liver, kidney and the heart. As communities continue to use M. oleifera leaves for its medicinal and nutritional values, there is need to find an antidote for its hepatotoxicity. Aim: The study established the reversal effect of N-Acetyl Cysteine (NAC) on M. oleifera aqueous leaf extract-induced hepatotoxicity in Wistar albino rats. Methods: Twenty-four (24) rats received a toxic dose (8.05 g/kg bwt) of M. oleifera leaf extract for 28 days to cause sub-acute hepatotoxicity. They were divided into 4 groups of 6 rats each. Group I received 1 ml normal (control group), Group II received 1000 ng/kg NAC, Group III received 1200 mg/kg NAC and Group IV received 1500 mg/kg NAC. Another group of 6 rats (Group V) received 0.75 mg/kg Paracetamol to cause hepatotoxicity. Group V (a positive control) received the prescribed clinical dose of 1200 mg/kg NAC which reverses the hepatotoxicity. All the NAC doses were given once a day intragastric for 7 days. On days: 1, 3 and 7 of receiving NAC, liver serum enzymes and bilirubin were measured. On day 7 the animals were sacrificed and liver tissue harvested for histopathology analysis. Results: A dose of 8.05 g/kg of M. oleifera leaf extract and 0.75 mg/kg Paracetamol were able to induce hepatotoxicity in Wister albino rats in 28 days. The M. oleifera extract induced hepatotoxic rats treated with NAC at doses of 1000 mg/kg, 1200 mg/kg and 1500 mg/kg, had a reduction in mean serum liver enzymes, plus reduced mean serum bilirubin levels. The liver histopathological analysis showed reduced inflammation after treatment with NAC for 3 and 7 days in the M. oleifera and paracetamol induced hepatotoxic rats. Conclusion: NAC can reverse M. oleifera leaf aqueous extract-induced sub-acute hepatotoxicity in Wistar Albino rats.