Ipomoea aquatica (Convolvulaceae) and Enhydra fluctuans (Asteraceae), two aquatic vegetables, are traditionally used against heavy metal toxicity in traditional medicines in India. The present study aimed to explore the protective role of edible (aqueous) extracts of I. aquatica (AEIA) and E. fluctuans (AEEF) against Cd-intoxication.
The extracts were chemically standardized by spectroscopic and HPLC analysis. The cytoprotective roles of AEIA and AEEF were measured on mouse hepatocytes. The effect on redox status were measured after incubating the hepatocytes with CdCl2 (30 μM) along with AEIA or AEEF (400 μg/ml). The effects on the expressions of apoptotic signal proteins were estimated. The protective roles of AEIA or AEEF were measured by in vivo assay in mice. Haematological, serum biochemical, tissue redox status, Cd bioaccumulation and histological parameters were evaluated to estimate the protective role of AEIA or AEEF (100 mg/kg) against CdCl2 (4 mg/kg) intoxication.
Phytochemical analysis revealed presence of substantial quantities of phenolics, flavonoids, saponins, carbohydrates and ascorbic acid in AEIA or AEEF. CdCl2 treated murine hepatocytes showed a gradual reduction of cell viability in a concentration dependent manner with an IC50 of ~30 μM. CdCl2 treated hepatocytes exhibited significantly enhanced levels (p < 0.01) of ROS production, lipid peroxidation, protein carbonylation and NADPH oxidase with concomitant depletion (p < 0.01) of antioxidant enzymes and GSH. However, AEIA or AEEF treatment along with CdCl2 significantly restored the aforementioned parameters in murine hepatocytes near to normalcy. Besides, AEIA or AEEF significantly counteracted (p < 0.05-0.01) with ROS mediated alteration of transcription levels of signal proteins viz. Bcl-2, BAD, Cyt-C, Caspases, Fas and Bid. In in vivo bioassay, CdCl2 treatment caused significantly high Cd bioaccumulation and oxidative stress in the liver, kidney, heart, brain and testes in mice. In addition, the haematological and serum biochemical parameters were significantly altered in the CdCl2 treated animals. Simultaneous administration of AEIA or AEEF could significantly restore the tested parameters to the near-normal status.
The extracts would offer the overall protective effect via counteracting with Cd mediated oxidative stress and/or promoting the elimination of Cd by chelating.