Study of arsenic accumulation in rice and evaluation of protective effects of Chorchorus olitorius leaves against arsenic contaminated rice induced toxicities in Wistar albino rats

The current research work was designed to investigate the As accumulation in different parts of rice and to evaluate the protective effects of C. olitorius leaves against As contaminated rice induced toxicities. To accomplish the first objective, a pot experiment was conducted where accumulation of As were found in high amounts in root followed by straw, husk and grain. In addition, the highest amount of As accumulation in different parts of rice was found in 50 mg/L As containing irrigation water which suggests that for irrigation purpose, As contaminated water cannot be used. Moreover, we noticed that As accumulation in different parts of rice were significantly higher than the permissible limits of WHO. Therefore, As contaminated rice and straw should not be consumed as human feed and cattle feed respectively. In the absolute control condition (0 mg/L), a trace amount of As accumulation was found that might be due to the background As in the soil. These findings are affirmative with the findings of Abedin et al. [16] and Imamul Huq et al. [17].

It is noticed from the earlier investigations that As can exhibit its toxicities by inducing haematological perturbations. Similar findings were also observed in this study. In the present study, we noticed significant reduction of Hb, total RBC count and total WBC count in As contaminated rice treated group (Group-II). The reduced Hb concentration and total RBC count might be due to binding ability of As to Hb that leads to inhibition of heme synthesis pathway [18]. Furthermore, decreased level of total WBC count might be due to apoptotic effect of As on plasma cells as also studied by Rousselot et al. [19]. We found no significant differences in platelet count among the groups in this study. Similar findings were also observed by Ferzand et al. [20]. A significant improvement of altered haematological parameters was observed in ameliorative group (Group-IV) compared to Group-II that confirms the beneficial roles of C. olitorius in restoring hematological parameters.

Arsenic can generate free radicals that promote lipid peroxidation by attacking polyunsaturated fatty acids in membranes, setting off a free radical chain reaction sequence. Peroxidation of lipid is known to cause membrane disruption, resulting in the loss of membrane integrity and leakage of microsomal enzymes [21]. AST and ALT are two prominent liver marker enzymes which are cytoplasmic in origin and are released into circulation after cellular damage [22]. That’s why increased activities of these enzymes in serum are an indication of hepatic damage. In the present study, we observed that As contaminated rice administration substantially increased the serum AST and ALT activities as also reported by Islam et al. [23]. On the contrary, co-administration of C. olitorius leaves as a food supplement remarkably reduced the As induced elevation of serum AST and ALT activities. These findings suggest the hepatoprotective role of C. olitorius leaves against As contaminated rice induced liver injury in rat.

Renal dysfunction is one of the major health effects of chronic As exposure, and increased levels of serum urea have been reported to be associated with renal dysfunction [24]. In the present study, we have also found increased serum urea levels in As contaminated rice intoxicated rats which is an indication of the detrimental effects of As on kidney. C. olitorius leaves potentially reduced the As induced elevation of serum urea levels which indicates its nephroprotective role.

Reduced protein synthesis is associated with As intoxication as showed by Mehta and Hundal [25] and our results are corroborating with their findings. We observed reduced serum protein level in Group-II compared to Group-I. This reduction might be attributed to increased proteolytic activity or reduced protein synthesis or destruction of hepatic protein synthesizing sub-cellular structures. In addition, it is also possible that severe nephrotoxic lesions caused drainage of protein through the urine, resulting in hypoproteinaemia. Interestingly, co-administration of C. olitorius leaves with As contaminated rice significantly (p??0.05) reversed the serum protein level towards control. One possibility for increasing serum protein level might be due to antioxidant activity of C. olitorius leaves with a significant amount of ?-tocopherol equivalent Vitamin E [26] where vitamin E could decrease hepatic insulin resistance allowing insulin to stimulate the incorporation of amino acids into protein [27].

Cardiovascular disease is one of the prominent causes of As related mortality [28]. Increased levels of TG, TC and LDL-C are often associated with cardiovascular diseases such as atherosclerosis. In this study, we also observed elevated levels of TG, TC and LDL-C in As contaminated rice treated rats (Group-II) which were reversed to normal levels with the supplementation of C. olitorius leaves (Group-IV). This may be an indication of the anti-hyper lipidemic property of C. olitorius leaves as also reported by Adedosu et al. [29]. These findings open up the possibility to employ the C. olitorius leaves in treating cardiovascular diseases in near future.

Due to chronic exposure, As is known to accumulate in different organs such as spleen, kidney, heart, liver etc. Among the organs, spleen is more prone to accumulate As than other organs as studied by Nasir et al. [30] and our results are in full agreement with their findings. Lower As deposition was found in organs of rat treated with As contaminated rice plus C. olitorius than those treated with As contaminated rice alone. C. olitorius leaves might have thiol-containing amino acids which could play role to reduce tissue As burden in rat.

Histopathological evaluation of different organs revealed that As contaminated rice caused various pathological alterations in the tissues. However, supplementation of C. olitorius leaves with As contaminated rice could prevent the pathological alterations and also maintain the normal histo-architecture of tissues.