Evaluation of toxicological effects of an aqueous extract of shells from the pecan nut Carya illinoinensis (Wangenh.) K. Koch and the possible association with its inorganic constituents and major phenolic compounds

Abstract

Background. Industrial processing of the pecan nut Carya illinoinensis K. Koch generated a large amount of shells, which have been used to prepare nutritional supplements and medicinal products; however, the safe use of shells requires assessment. This study evaluated the toxic, genotoxic, and mutagenic effects of pecan shell aqueous extract (PSAE) and the possible contribution of phenolic compounds, ellagic and gallic acids, and inorganic elements present in PSAE to induce toxicity. Results. Levels of inorganic elements like K, P, Cl, and Rb quantified using the Particle-Induced X-Ray Emission method were higher in PSAE than in pecan shells, while Mg and Mn levels were higher in shells. Mice showed neurobehavioral toxicity when given high PSAE doses (200– 2,000mg kg−1). The LD50 was 1,166.3mg kg−1. However, PSAE (50–200mg⋅kg−1) and the phenolic compounds (10–100mg kg−1) did not induce DNA damage or mutagenicity evaluated using the comet assay and micronucleus test. Treatment with ellagic acid (10–100mg kg−1) decreased triglyceride and glucose levels, while treatments with PSAE and gallic acid had no effect. Conclusion. Pecan shell toxicity might be associated with high concentrations of inorganic elements such as Mn, Al, Cu, and Fe acting on the central nervous system, besides phytochemical components, suggesting that the definition of the safe dose should take into account the consumption of micronutrients.