Azeez OI and Adegboyega IO

Lead as very common in the environment as heavy released through burning of various fuels, mining, and manufacturing of lead batteries. Therefore, constant exposure to lead predisposes people to lead induced toxicity with acute and prolonged exposure. This study investigated the ameliorative roles of Curcuma longa rhizome extracts (aqueous and ethanolic) on the haematological, erythrocyte osmotic fragility, plasma biochemistry and indicators of associated oxidative stress in the rats.

Thirty-five adult male Wistar rats that weigh 150-190 g used in this experiment were randomly divided into seven groups, A to G which consist five rats in each group. The positive control (group A) was given distilled water, Group B rats were administered a dose of 150 mg/kg lead acetate only. Groups C-D rats were given 150 mg/kg lead acetate plus 100 and 200 mg/kg aqueous extract of Curcuma longa respectively, while group E and F rats were exposed to a dose of 150 mg/kg lead acetate with 100 and 200 mg/kg of Curcuma longa ethanol extract, respectively. Finally group G rats were administered a dose of 150 mg/kg lead acetate and 100 mg/kg Gallic acid, a known antioxidant, for a period of twenty-eight (28) days. All extracts were dissolved in 5% Tween 80, which was also given to the control groups A, B and G. At days 14 and 28, blood was collected for haematological parameters, erythrocyte osmotic fragility and plasma biochemist. At day 28, kidneys, liver and testes were collected for histology and determination of markers/indicators of oxidative stress.

Exposure to lead acetate resulted in mild macrocytic hypochromic anaemia as indicated by decreased values of Hb concentration, PCV and RBC with increased MCV and decreased MCHCH as compared to the untreated control. The osmotic fragility in lead only treated group B was higher than were those of the control and those treated with aqueous and ethanol extract of Curcuma longa as well as Gallic acid. Concomitant exposure to lead and Curcuma longa showed a degree of response to the anaemia. The extracts also modulated the elevated erythrocyte osmotic fragility seen in lead only treated group B. Furthermore, signs of mild liver and kidney damages in lead toxicity were observed, following elevated AST and ALT levels. The LDL was also elevated while HDL was reduced. The damages were however ameliorated by Curcuma longa aqueous and ethanol extract, especially at 200 mg/kg dosage and Gallic acid.

Oxidative stress indicators such as H₂O₂ and MDA values were higher, while antioxidant enzymes, GSH, GPx and SOD were depleted in lead only treated rats in the liver, kidneys, and testes. Degenerative changes, congestion and were also observed in the liver, kidneys and testes in Group B, but the extracts were able to ameliorate the oxidative stress damages and histopathological changes in those treated concurrently with the toxicant and Curcuma longa aqueous and ethanol extracts, both at 100 mg/kg and 200 mg/kg dosages.

This study further established the toxic effects of exposure to lead by causing anaemia, increased erythrocyte membrane fragility and multiple organ damage by increasing oxidative stress and exhaustion of endogenous antioxidants. The effect of lead was however corrected by Curcuma longa extracts in a manner that is similar to that of gallic acid. These effects of Curcuma longa extract may be linked with flavonoids and phenolic compounds with antioxidant effects in Curcuma longa.

DOI: 10.22271/phyto.2023.v12.i5c.14734

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