PROTECTIVE AND THERAPEUTIC EFFECTS OF PROPOLIS AGAINST MONOSODIUM GLUTAMATE (MSG) TOXICITY IN RAT BRAIN: HISTOPATHOLOGICAL STUDY

Abstract

Monosodium glutamate (MSG) is the salt of nonessential glutamic acid. It has a property to enhance the perception that flavors are well blended and full-bodied. Propolis is a resinous substance collected by honeybees from the bud and bark of certain trees and plants. It has been used in folk medicine from ancient times in many countries. The present study aimed to investigate the protective and curative effect of propolis against MSG on the rat brain. Accordingly, fifty male albino rats were divided into five groups. The first group served as control, whereas the second group was administered propolis at an oral daily dose of 200 mg/kg b. w. for eight weeks. The third group received MSG 1 g/kg b. w. for eight weeks. The fourth group (protective group) was initialy administered with propolis alone for 4 weeks, and followed by MSG in association with propolis for 4 weeks. The fifth group (therapeutic group) was first given MSG alone for 4 weeks and secondly administered propolis in association with MSG for 4 weeks. At the end of four and eight weeks, brain tissues were collected for histopathological study purposes. Histopathological studies of MSG-treated rats displayed deleterious alterations in brain tissues as indicated by perivascular oedema and cuffing. Some blood vessels were congested and there was vacuolation of some neurons. The protective group showed gliosis in the cerebrum. There were still some odematous changes and perivascular cuffing which were still persistent. Propolis extract in the curative group caused active hyperaemia of the brain, blood vessels were congested and showed perivascular oedema and some neurons exhibited a marked vacuolation. It may be concluded that the results confirm the toxic effect of MSG on the brain and the protective effect of propolis, especially when administrated as a propolis alone.