Effect of Aerva lanata on calcium oxalate urolithiasis in rats

Calcium oxalate (CaOx) stone was induced in rats using 0.75% of ethylene glycol in drinking water for 28 days. Ethylene glycol treated rats showed significant increase in the activities of oxalate synthesizing enzymes such as glycolic acid oxidase (GAO) in liver and lactate dehydrogenase (LDH) in liver and kidney. CaOx crystal deposition, as indicated by increased excretion of stone-forming constituents in urine, such as calcium, oxalate, uric acid, phosphorus and protein and decreased concentration of inhibitors, such as citrate and magnesium was observed in ethylene glycol induced urolithic rats. Histopathological studies also confirmed the deposition of CaOx crystals. Administration of Aerva lanata aqueous suspension (2g/kg body wt/dose/day for 28 days) to CaOx urolithic rats had reduced the oxalate synthesizing enzymes, diminished the markers of crystal deposition in the kidney. The results of the present study confirmed that A. lanata can be used as an curative agent for urolithiasis.     

Effect of citrate feeding on free radical induced changes in experimental urolithiasis.

Feeding calculi producing diet (CPD) to rats for 4 weeks produced calcium oxaltate stones. Supplementation of sodium citrate to CPD (c-CPD) prevented stone formation. Except oxalate, the excretion of calcium, phosphorus and magnesium was restored to normal in c-CPD fed rats. The CPD fed rats exhibited increase in glycolic acid oxidase (GAO) and lactate dehydrogenase (LDH) activities and only GAO activity was partially restored in c-CPD fed rats. Kidney sub-cellular fractions of calculi producing diet (CPD) fed rats showed increased susceptibility for lipid peroxidation in presence of promotors. Antioxidant enzyme activities of superoxide dismutase (SOD), catalase and glutathione peroxidase and antioxidant concentrations of reduced glutathione, total thiols, ascorbic acid and vitamin E were significantly decreased while the xanthine oxidase activity, and concentrations of hydroxyl radical, diene conjugates and hydroperoxides were significantly increased in CPD fed rats. The susceptibility to lipid peroxidation, activities of antioxidant enzymes, and the concentration of antioxidants were not normalized by feeding citrate.     

Methionine feeding prevents kidney stone deposition by restoration of free radical mediated changes in experimental rat urolithiasis

Feeding calculi producing diet (CPD) to rats for 4 weeks produced calcium oxalate stones deposition. Supplementation of methionine to CPD (m-CPD) prevented the stone deposition. However the urine pH and excretion of oxalate and calcium in m-CPD-fed rats was still as high as in CPD-fed groups compared to that of the control group. The CPD-fed rats exhibited an increase in liver oxalate synthesizing enzymes and glycolic acid oxidase (GAO) and lactate dehydrogenase (LDH), and these activities were not restored in m-CPD-fed rats. Similarly, the elevated LDH activity and oxalate concentration observed in the kidney of CPD-fed rats were not restored by methionine supplementation. Kidney sub-cellular fractions of CPD-fed rats showed increased susceptibility for lipid peroxidation in presence of iron, ascorbate, and t-butyl hydroperoxide. Antioxidant enzyme activities of superoxide dismutase (SOD), catalase, and glutathione peroxidase and antioxidant concentrations of reduced glutathione, total thiols, ascorbic acid, and vitamin E were significantly decreased, while the xanthine oxidase activity and concentrations of hydroxyl radical, diene conjugates, and hydroperoxides were significantly increased in CPD-fed rats. The susceptibility to lipid peroxidation, activities of antioxidant enzymes, and the concentration of antioxidants were normalized in m-CPD—fed rats, thus suggesting that methionine feeding prevents the stone formation by neutralizing the free radical induced changes.     

Supplementation of vitamin E and selenium prevents hyperoxaluria in experimental urolithic rats

Renal injury is considered as one of the prerequisites for calcium oxalate retention. In order to determine the role of lipid peroxidation related effects for hyperoxaluria, we evaluated the alterations in lipid peroxidation, antioxidants and oxalate synthesizing enzymes in lithogenic rats with response to vitamin E + selenium treatment. In kidney of lithogenic rats, the level of lipid peroxidation and the activities of oxalate synthesizing enzymes were found to be increased whereas the levels/activities of non-enzymatic and enzymatic antioxidants were found to be decreased. The urinary excretion of both oxalate and calcium were significantly elevated. Supplementation of lithogenic rats with vitamin E + selenium decreased the levels of lipid peroxides and the activities of oxalate synthesizing enzymes like glycolic acid oxidase (GAO), lactate dehydrogenase (LDH), xanthine oxidase (XO) with a concomitant increase in the activities of enzymatic antioxidants like superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glucose-6-phosphate dehydrogenase (G6PDH) and increased levels of non-enzymatic antioxidants like ascorbic acid, alpha-tocopherol and reduced glutathione (GSH). The urinary excretion of oxalate and calcium were normalized. The antioxidants vitamin E + selenium thereby protected from hyperoxaluria.     

Effect of cyclosporin A treatment on renal calcium oxalate binding in experimental hyperoxaluria

This study was aimed to investigate the effect of Cyclosporin A administration on renal calcium oxalate binding under hyperoxaluric condition.Cyclosporin A administration or ammonium oxalate treatment increased calcium oxalate binding, which was further increased in kidney treated with cyclosporin A and ammonium oxalate together. The increase of calcium oxalate binding was associated with lipid peroxidation as well as with a concomitant decrease in total thiol in both rat and human kdiney homogenate.Cyclosporin A administration to hyperoxaluric rats resulted with increased calcium oxalate binding protein. However there was no change with specific activity of the protein.In conclusion, Cyclosporin A administration either to normal or hyperoxaluric rats is resulted with increased concentration of calcium oxalate binding protein as well as enhanced activity due to membrane lipid peroxidation.     

Attenuation of oxalate-induced nephrotoxicity by eicosapentaenoate-lipoate (EPA-LA) derivative in experimental rat model

Hyperoxaluria is one of the major risk factors for the formation of urinary calcium oxalate stones. Calcium oxalate crystals and their deposition have been implicated in inducing renal tubular damage. Lipoic acid (LA) and eicosapentaenoic acid (EPA) have been shown to ameliorate the changes associated with hyperoxaluria. This prompted us to investigate the nephroprotectant role of EPA-LA, a new derivative, in vivo in hyperoxaluric rats. Elevation in the levels of calcium, oxalate and phosphorus, the stone-forming constituents, were observed in calculogenic rats as a manifestation of crystal deposition.Tubular damage to the renal tissue was assessed byassaying the excretion of marker enzymes in the urine. Damage to the tubules was indicated by increased excretion of alkaline phosphatase (ALP), lactate dehydrogenase (LDH), gamma-glutamyl transferase (gamma-GT), beta-Glucuronidase (beta-GLU) and N-Acetyl beta-D glucosaminidase (NAG). Fibrinolytic activity was found to be reduced. Administration of EPA, LA and EPA-LA reduced the tubular damage and decreased the markers of crystal deposition markedly, which was substantiated by the reduction in weight of bladder stone formed. Our results highlight that EPA-LA is the most effective drug in inhibiting stone formation and mitigating renal damage caused by oxalate toxicity, thus confirming it as a nephroprotectant. Further work in this direction is warranted to establish the therapeutic effectiveness of this new derivative.     

Metabolism of [1-14C]glyoxylate, [1-14C]-glycollate, [1-14C]glycine and [2-14C]-glycine by homogenates of kidney and liver tissue from hyperoxaluric and control subjects

1. The metabolism of [1-(14)C]glyoxylate to carbon dioxide, glycine, oxalate, serine, formate and glycollate was investigated in hyperoxaluric and control subjects' kidney and liver tissue in vitro. 2. Only glycine and carbon dioxide became significantly labelled with (14)C, and this was less in the hyperoxaluric patients' kidney tissue than in the control tissue. 3. Liver did not show this difference. 4. The metabolism of [1-(14)C]glycollate was also studied in the liver tissue; glyoxylate formation was demonstrated and the formation of (14)CO(2) from this substrate was likewise unimpaired in the hyperoxaluric patients' liver tissue in these experiments. 5. Glycine was not metabolized by human kidney, liver or blood cells under the conditions used. 6. These observations show that glyoxylate metabolism by the kidney is impaired in primary hyperoxaluria.     

Effect of DL alpha-lipoic acid on some carbohydrate metabolising enzymes in stone forming rats.

DL alpha-lipoic acid has been shown to prevent the induced precipitation of calcium oxalate crystals in the renal tissues of laboratory animals. The acid seems to have a profound influence on carbohydrate metabolism in diabetic rats. Here the effect of alpha-lipoic acid was studied on certain key carbohydrate metabolising enzymes in the tissues of calcium oxalate stone forming rats administered with glycollate as oxalate precursor. There was augmentation of glycolysis in the renal tissues of stone forming as well as lipoate administered rats. The two major gluconeogenic enzymes, glucose-6-phosphatase (G6P) and fructose-1, 6 diphosphatase (FDP) were significantly inhibited in tissues of calculogenic rats. Lipoic acid also reduced the enzyme activities significantly. The citric acid cycle enzymes were not influenced to an appreciable extent. The observed alterations are likely to be due to the regulatory effects of oxalate and lipoate on the enzyme systems.     

Induction of lipid peroxidation in calcium oxalate stone formation

The function of lipid peroxidation and the anti-peroxidative enzymes of rat liver and kidney were investigated under hyperoxaluric and stone forming conditions. The experimental animals showed higher malondialdehyde content in liver and kidney than that of control. A significant increase in malondialdehyde release was observed in the experimental liver or kidney when incubated with either ferrous sulphate or hydrogen peroxide compared to that of control liver or kidney. Superoxide dismutase activity was not affected in the hyperoxaluric rats while there was a moderate increase in the stone forming rats when compared to control. Highly significant decrease in catalase activity was observed in both conditions in liver and kidney compared to control.     

Oxalate synthesis from [14C1]glycollate and [14C1]glycoxylate in the hepatectomized rat

Hepatectomy significantly altered the metabolism of [1-¹⁴C]glyoxylate and [1-¹⁴C]glycollate in the rat. The production of ¹⁴CO₂ was reduced by 47% and 77%–86%, respectively, indicating the involvement of the liver in the oxidation of both substrates. Unidentified intermediates, assumed to be primary glycine, serine and ethanolamine, were also reduced by over 50%, was would be expected from the removal of the aminotransferase enzymes through the hepatectomy. The biosynthesis of [¹⁴C]oxalate from [1-¹⁴C]glycollate was reduced by more than 80% in the hepatectomized rat. This suggests that this oxidation is primarily catalyzed by the liver enzymes, glycolic acid oxidase and glycolic acid dehydrogenase, in the intact rat. The limited formation of [¹⁴C]oxalate from [¹⁴₁]glycollate observed in the hepatectomized rat is probably catalyzed by lactate dehydrogenase or extrahepatic glycolic acid oxidase. Hepatectomy did not significantly alter the rate of formation of [¹⁴C]oxalate from [¹⁴₁]glyoxylate. However, since saturating concentrations of glyoxylate could not be used because of the toxicity of this substrate, the involvement of glycollic acid oxidase in this oxidation reaction in the intact rat can not be ruled out. In the hepatectomized rat, lactate dehydrogenase appears to be the enzyme making the major contribution, although other as yet not identified enzymes may be contributing. The increased deposition of oxalate in the tissues, oxalosis, may result from the shift in oxalate synthesis from the liver to the extrahepatic tissues.     

The pathways of oxalate formation from phenylalanine,tyrosine, tryptophan and ascorbic acid in the rat

The metabolic pathway by which L-[¹⁴C₁]phenylalanine, L-[¹⁴C₁]tyrosine, L-[¹⁴C₁]tryptophan, and L-[¹⁴C₁]ascorbic acid are converted to [¹⁴C]oxalate have been investigated in the male rate. Only [¹⁴C]oxalate was detected in the urine of rats injected with L-[¹⁴C₁]ascorbic acid, but [¹⁴C]-labeled oxalate, glycolate, glyoxylate, glycolaldehyde, glycine, and serine were recovered from the [¹⁴C₁]-labeled aromatic amino acids. DL-Phenyllactate, an inhibitor of glycolic acid oxidase and glycolic acid dehydrogenase, reduced the amount of [¹⁴C]oxalate recovered in the urine of rats given the [¹⁴C₁]-labeled aromatic amino acids, but increased the amount of [¹⁴C]glycolate formed from L-[¹⁴C₁]-phenylalanine and L-[¹⁴C₁]tyrosine and the amount of [¹⁴C]glycolate produced from [¹⁴C₁]tryptophan. Based on the [¹⁴C]labeled intermediates identified and the relative distribution of the radioactivity, it is postulated that phenylalanine and tyrosine are converted to oxalate via glycolate which is oxidized directly to oxalate by glycolic acid dehydrogenase. Tryptophan is metabolized via glyxylate which is oxidized directly to oxalate by glycolic acid oxidase. Neither glycolate, glyoxylate, glycolic acid oxidase or glycolic acid dehydrogenase are involved in the formation of oxalate from ascorbic acid.     

Characterization of histone (H1B) oxalate binding protein in experimental urolithiasis and bioinformatics approach to study its oxalate interaction

The rat kidney H1 oxalate binding protein was isolated and purified. Oxalate binds exclusively with H1B fraction of H1 histone. Oxalate binding activity is inhibited by lysine group modifiers such as 4',4'-diisothiostilbene-2,2-disulfonic acid (DIDS) and pyridoxal phosphate and reduced in presence of ATP and ADP. RNA has no effect on oxalate binding activity of H1B whereas DNA inhibits oxalate binding activity. Equilibrium dialysis method showed that H1B oxalate binding protein has two binding sites for oxalate, one with high affinity, other with low affinity. Histone H1B was modeled in silico using Modeller8v1 software tool since experimental structure is not available. In silico interaction studies predict that histone H1B-oxalate interaction take place through lysine121, lysine139, and leucine68. H1B oxalate binding protein is found to be a promoter of calcium oxalate crystal (CaOx) growth. A 10% increase in the promoting activity is observed in hyperoxaluric rat kidney H1B. Interaction of H1B oxalate binding protein with CaOx crystals favors the formation of intertwined calcium oxalate dehydrate (COD) crystals as studied by light microscopy. Intertwined COD crystals and aggregates of COD crystals were more pronounced in the presence of hyperoxalauric H1B.     

大蒜素通过抑制OPN表达和NF‑κB通路活化对大鼠肾结石形成的作用研究

大蒜素可改善草酸诱导的肾小管上皮细胞损伤,以肾结石大鼠为研究对象,探讨大蒜素对肾结石大鼠的作用及其可能的机制。采用1%乙二醇+2%氯化铵混合液灌胃造模（空白组除外）,分别灌胃大蒜素7.5 mg·kg^-1（低剂量大蒜素组）、15 mg·kg^-1（高剂量大蒜素组）、胃枸橼酸氢钾钠颗粒0.6 g·kg^-1（阳性对照组）,其余组灌胃0.9%氯化钠溶液（空白组）,检测各组大鼠与肾结石疾病相关的指标。与空白组相比,模型组大鼠肾指数、肌酐（creatinine,Cr）、血清尿素氮（blood urea nitrogen,BUN）水平和天冬氨酸转氨酶（aspartate aminotransferase,AST）、谷丙转氨酶（alanine aminotransferase,ALT）活性及24 h尿量、尿液中草酸、钙和磷含量显著升高（P<0.05）,草酸钙结晶评分显著升高（P<0.05）,镁含量显著降低（P<0.05）,骨桥蛋白（osteopontin,OPN）表达显著升高（P<0.05）,核因子κB（nuclear factor-κB,NF-κB）通路活化;与模型组相比,低剂量大蒜素组、高剂量大蒜素组和阳性对照组大鼠肾指数、Cr、BUN水平和AST、ALT活性、24 h尿量、尿液中草酸、钙和磷含量显著降低（P<0.05）,草酸钙结晶评分显著降低（P<0.05）,镁含量显著升高（P<0.05）,OPN表达显著降低（P<0.05）,NF?κB通路被抑制。结果表明,大蒜素通过改善大鼠肾功能指标、抑制骨桥蛋白表达和NF?κB通路活化进而抑制肾结石形成。     

Role of glutathione on renal mitochondrial status in hyperoxaluria

Role of glutathione on kidney mitochondrial integrity and function during stone forming process in hyperoxaluric state was investigated in male albino rats of Wistar strain. Hyperoxaluria was induced by feeding ethylene glycol (EG) in drinking water. Glutathione was depleted by administering buthionine sulfoximine (BSO), a specific inhibitor of glutathione biosynthesis. Glutathione monoester (GME) was administered for supplementing glutathione. BSO treatment alone or along with EG, depleted mitochondrial GSH by 40% and 51% respectively. Concomitantly, there was remarkable elevation in lipid peroxidation and oxidation of protein thiols. Mitochondrial oxalate binding was enhanced by 74% and 129% in BSO and BSO + EG treatment. Comparatively, EG treatment produced only a 33% increase in mitochondrial oxalate binding. Significant alteration in calcium homeostasis was seen following BSO and BSO + EG treatment. This may be due to altered mitochondrial integrity and function as evidenced from decreased activities of mitochondrial inner membrane marker enzymes, succinate dehydrogenase and cytochrome-c-oxidase and respiratory control ratio and enhanced NADH oxidation by mitochondria in these two groups. NADH oxidation (r = -0.74) and oxalate deposition in the kidney (r = -0.70) correlated negatively with mitochondrial glutathione depletion. GME supplementation restored normal level of GSH and maintained mitochondrial integrity and function, as a result of which oxalate deposition was prevented despite hyperoxaluria. These results suggest that mitochondrial dysfunction resulting from GSH depletion could be a contributing factor in the development of calcium oxalate stones.     

Isolation and characterization of glycolic acid oxidase from human liver.

Glycolic acid oxidase has been isolated from human liver and purified over 3000-fold to a specific activity of 123 U/mg protein by a 5-step procedure. The preparation gave a single protein band on polyacrylamide gel electrophoresis, required flavin mononucleotide for catalytic activity, had a pH optimum between 8.2-8.8 depending on the substrate, and had a molecular weight of 105 000. The enzyme has a broad specificity towards alpha-hydroxy acids. Glycolate (Km = 3.3 . 10(-4) M) was the most effective substrate. The enzyme was stable for several months when stored as an (NH4)2SO4 precipitate or in 15% glycerol. Since glycolate inhibits the oxidation of glyoxylate to oxalate by glycolic acid oxidase, it is suggested that glycolic acid oxidase contributes to the synthesis of oxalate in vivo when the glyoxylate concentration is high and the glycolate concentration is low.     

Enteric oxalate elimination is induced and oxalate is normalized in a mouse model of primary hyperoxaluria following intestinal colonization with Oxalobacter

Oxalobacter colonization of rat intestine was previously shown to promote enteric oxalate secretion and elimination, leading to significant reductions in urinary oxalate excretion (Hatch et al. Kidney Int 69: 691-698, 2006). The main goal of the present study, using a mouse model of primary hyperoxaluria type 1 (PH1), was to test the hypothesis that colonization of the mouse gut by Oxalobacter formigenes could enhance enteric oxalate secretion and effectively reduce the hyperoxaluria associated with this genetic disease. Wild-type (WT) mice and mice deficient in liver alanine-glyoxylate aminotransferase (Agxt) exhibiting hyperoxalemia and hyperoxaluria were used in these studies. We compared the unidirectional and net fluxes of oxalate across isolated, short-circuited large intestine of artificially colonized and noncolonized mice. In addition, plasma and urinary oxalate was determined. Our results demonstrate that the cecum and distal colon contribute significantly to enteric oxalate excretion in Oxalobacter-colonized Agxt and WT mice. In colonized Agxt mice, urinary oxalate excretion was reduced 50% (to within the normal range observed for WT mice). Moreover, plasma oxalate concentrations in Agxt mice were also normalized (reduced 50%). Colonization of WT mice was also associated with marked (up to 95%) reductions in urinary oxalate excretion. We conclude that segment-specific effects of Oxalobacter on intestinal oxalate transport in the PH1 mouse model are associated with a normalization of plasma oxalate and urinary oxalate excretion in otherwise hyperoxalemic and hyperoxaluric animals.     

N-acetylcysteine with apocynin prevents hyperoxaluria-induced mitochondrial protein perturbations in nephrolithiasis

Diminished mitochondrial activities were deemed to play an imperative role in surged oxidative damage perceived in hyperoxaluric renal tissue. Proteomics is particularly valuable to delineate the damaging effects of oxidative stress on mitochondrial proteins. The present study was designed to apply large-scale proteomics to describe systematically how mitochondrial proteins/pathways govern the renal damage and calcium oxalate crystal adhesion in hyperoxaluria. Furthermore, the potential beneficial effects of combinatorial therapy with N-acetylcysteine (NAC) and apocynin were studied to establish its credibility in the modulation of hyperoxaluria-induced alterations in mitochondrial proteins. In an experimental setup with male Wistar rats, five groups were designed for 9?d. At the end of the experiment, 24-h urine was collected and rats were euthanized. Urinary samples were analyzed for kidney injury marker and creatinine clearance. Transmission electron microscopy revealed distorted renal mitochondria in hyperoxaluria but combinatorial therapy restored the normal mitochondrial architecture. Mitochondria were isolated from renal tissue of experimental rats, and mitochondrial membrane potential was analyzed. The two-dimensional electrophoresis (2-DE) based comparative proteomic analysis was performed on proteins isolated from renal mitochondria. The results revealed eight differentially expressed mitochondrial proteins in hyperoxaluric rats, which were identified by Matrix-assisted laser desorption/ionization time of flight/time of flight (MALDI-TOF/TOF) analysis. Identified proteins including those involved in important mitochondrial processes, e.g. antioxidant defense, energy metabolism, and electron transport chain. Therapeutic administration of NAC with apocynin significantly expunged hyperoxaluria-induced discrepancy in the renal mitochondrial proteins, bringing them closer to the controls. The results provide insights to further understand the underlying mechanisms in the development of hyperoxaluria-induced nephrolithiasis and the therapeutic relevance of the combinatorial therapy.     

Oxalate balance in fat sand rats feeding on high and low calcium diets

Oxalate reduces calcium availability of food because it chelates calcium, forming the sparingly soluble salt calcium-oxalate. Nevertheless, fat sand rats (Psammomys obesus; Gerbillinae) feed exclusively on plants containing much oxalate. We measured the effects of calcium intake on oxalate balance by comparing oxalate intake and excretion in wild fat sand rats feeding on their natural, oxalate-rich, calcium-poor diet with commercially-bred fat sand rats feeding on an artificial, calcium-rich, oxalate-poor diet of rodent pellets. We also tested for the presence of the oxalate degrading bacterium Oxalobacter sp. in the faeces of both groups. Fat sand rats feeding on saltbush ingested significantly more oxalate than fat sand rats feeding on pellets (P < 0.001) and excreted significantly more oxalate in urine and faeces (P < 0.01 for both). However the fraction of oxalate recovered in excreta [(oxalate excreted in urine + oxalate excreted in faeces)/oxalate ingested] was significantly higher in pellet-fed fat sand rats (61%) than saltbush-fed fat sand rats (27%). We found O. sp. in the faeces of both groups indicating that fat sand rats harbor oxalate degrading bacteria, and these are able, to some extent, to degrade oxalate in its insoluble form.     

Influence of aqueous extract of Hibiscus sabdariffa L. petal on cadmium toxicity in rats

The effects of chronic exposure to cadmium (Cd) on some selected biochemical parameters, as well as the possible protective role of aqueous extracts of Hibiscus sabdariffa L petal were studied in 12-wk-old male Wistar albino rats. Exposure to Cd caused a significant increase in plasma l-alanine aminotransferases (ALT) only but with a corresponding decrease in liver l-alanine and l-aspartate aminotransferases (L-ALT, L-AST) when compared to the Cd-free control. Total superoxide dismutase activity was decreased in the liver, testis, and prostate of Cd-exposed rats, whereas malondialdehyde (MDA) concentrations were increased relative to the Cd-free control. The metal significantly increased prostatic acid phosphatase activity in the prostate, but decreased the body weight gain of the rats and organ/body weight ratio for prostate and testis compared to the Cd-free control. Pretreatment of rats with aqueous extract of H. sabdariffa resulted in significantly less hepatotoxicity than with Cd alone as measured by plasma ALT and liver ALT and AST activities. The extract also protected the rats against Cd-induced liver, prostate, and testis lipoperoxidation as evidenced by significantly reduced MDA values in these organs, as well as reduced prostatic acid phosphatase activity in the prostate, when compared to the Cd-only exposed rats. Also, when compared to the organ/body weight ratios obtained from rats exposed to Cd alone the prostate and testis were protected by the extract as shown by enhanced prostate/body weight and testis/body weight ratios of Cd- and extract-treated rats. These data suggest that H. sabdarrifa L might be protective in Cd toxicity.