Tualang honey and its methanolic fraction ameliorate lipopolysaccharide-induced oxidative stress, amyloid deposition and neuronal loss of the rat hippocampus

Abstract

This study aims to evaluate the protective effects of Malaysian Tualang honey (TH) and its methanolic fraction (MTH) against oxidative stress, amyloid deposition and neuronal loss in the hippocampal tissue of lipopolysaccharide (LPS) rats. Sixty male Sprague Dawley rats were randomly divided into five groups: (1) control, (2) LPS (5 mg/kg), (3) LPS rats treated with 200 mg/kg TH, (4) LPS rats treated with 150 mg/kg MTH, and (5) LPS rats treated with 10 mg/kg memantine. The levels of catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GPr), superoxide dismutase (SOD), malondialdehyde (MDA), and beta-amyloid (Aβ) in the hippocampal tissues were determined using ELISA method. The CAT and GPx levels were significantly higher in all the treatment groups compared to the LPS group. The levels of GR and SOD were found to be significantly higher in the TH and memantine groups, and TH group, respectively. The TH and MTH groups, but not memantine, significantly lower MDA level compared to the LPS group. TH and memantine attenuated the effect of LPS where the levels of Aβ1−40 were higher and Aβ1−42 were lower compared to the LPS group. MTH, however, failed to lower the level of Aβ1−42. The number of Nissl-positive neurons in all hippocampal regions was significantly lower in the LPS group compared to the control group. Both TH and MTH treatments significantly ameliorate LPS-induced neuronal loss comparable to memantine, suggesting their neuroprotective potential. TH, however, exhibits slightly higher neuroprotective potential against oxidative stress and amyloid deposition when compared to MTH.