Acute and sub-chronic toxicological evaluation of Averrhoa carambola leaves in Sprague Dawley rats

Toxicity studies of condensed fuzheng extract in mice and rats

Nutritional supplements have been used to improve immune function. Condensed fuzheng extract (CFE) is a well-known traditional Chinese medicine (TCM) formula that is predominantly made from sheep placenta, Astragalus mongholicus Bunge, and Polygonatum kingianum Collett & Hemsl. However, the toxicological profile of CFE has not been determined. In this study, we investigated the acute (14 days) and sub-chronic (90 days) oral toxicities of CFE in mice and rats and the phytochemical composition of CFE.

Materials and methods

For the assessment of acute toxicity, 80 ICR mice of both sexes were randomly divided into four groups. Three groups were treated with 4500, 2250 and 1125 mg/kg/d bw CFE daily (n = 10/group per sex) for 14 days; a separate group was used as control. To test the sub-chronic toxicity, male and female Sprague Dawley rats were orally administered 8150, 4075 or 2037 mg/kg bw of CFE for 90 days; a control group was included. Hematological, biochemical, and histopathological markers were tested at the end of the experiment. The chemical composition of CFE was determined by UPLC-HRMS method.

Results

In both acute and sub-chronic toxicity studies, no mortalities, indications of abnormality, or treatment-related adverse effects were observed. The LD50 of CFE was higher than 4500 mg/kg. There were no significant changes in the hematological and biochemical data in the treatment group compared with the control group (p > 0.05). Histopathological analyses of the heart, liver, spleen, lungs, kidneys, thymus, testes (male rats) and ovaries (female rats) revealed no anatomical changes of each organ. Phytochemical analysis of CFE revealed the presence of flavonoids (highest abundance), phenols and alkaloids. In conclusion, our results showed that CFE is a safe and non-toxic formula. We also reported phytochemicals in CFE that may possess important pharmacological effects.

Averrhoa carambola leaves prevent dyslipidemia and oxidative stress in a rat model of poloxamer-407-induced acute hyperlipidemia

Background: The star fruit [Averrhoa carambola L (Oxalidaceae)] is traditionally used in the treatment of many ailments in many countries. It possesses several pharmacological activities, including antioxidant and anti-inflammatory effects. However, it contains the neurotoxic caramboxin and its high content of oxalic acid limits its consumption by individuals with compromised kidney function. This study assessed the anti-hyperlipidemic and antioxidant activities of different fractions of the methanolic extract of A. carambola leaves (MEACL). Methods: The antioxidant activity was investigated using FRAP, and ABTS and DPPH radical-scavenging assays and the inhibitory activity toward pancreatic lipase (PL) and HMG-CoA reductase was assayed in vitro. Acute hyperlipidemia was induced by poloxamer-407 (P-407) in rats and different fractions of MEACL (n-hexane, chloroform, n-butanol, ethyl acetate (EA), water, and chloroform) were orally administered. Cholesterol and triglycerides were determined at 0, 12, 24, and 48 h and LDL-C, vLDL-C, HDL-C, lipid peroxidation (LPO) and antioxidants were assayed after 48 h. The expression of ABCA1, ABCG5, ABCG8, LDL-R, SREBP-1, and SREBP-2 and the activity of HMG-CoA reductase were assayed in the liver of P-407-administered rats treated with the EA fraction. Results: The in vitro data revealed potent radical-scavenging activities of MEACL fractions with the most potent effect showed by the EA fraction that also suppressed the activities of HMG-CoA reductase and PL. In P-407-induced hyperlipidemic rats, all fractions prevented dyslipidemia as shown by the decrease in total cholesterol, triglycerides, LDL-C, vLDL-C and atherogenic index. MEACL and its fractions prevented LPO and boosted GSH, superoxide dismutase, glutathione peroxidase, and catalase in P-407-administered rats. The EA fraction showed more effective anti-hyperlipidemic and antioxidant effects than other fractions and downregulated SREBP-2 while upregulated ABCA1 and LDL-R and ameliorated LPL and HMG-CoA reductase in hyperlipidemic rats. Conclusion: MEACL showed in vitro and in vivo antioxidant activity and the EA fraction significantly ameliorated dyslipidemia in a rat model of P-407-induced acute hyperlipidemia by modulating LPL, PL, HMG-CoA reductase, and cholesterolgenesis-related factors. Therefore, the leaves of A. carambola represent a safe alternative for the star fruit particularly in kidney disease patients, and the EA is the most effective anti-hyperlipidemic and antioxidant fraction.