Brain activation by the umami taste substance monosodium L-glutamate via gustatory and visceral signaling pathways, and its physiological significance due to homeostasis after a meal

Monosodium glutamate induces memory and hepatic dysfunctions in mice: ameliorative role of Jobelyn® through the augmentation of cellular antioxidant defense machineries

This study investigated the effect of high doses of monosodium glutamate (MSG), a known food additive on hepatic, memory and locomotor functions in mice, and the ameliorative potentials of Jobelyn^® (JB), a unique dietary supplement. Twenty four  male Swiss mice  divided into 4 groups (n = 6) were given MSG (2, 4 and 8 g/kg) or normal saline (10 mL/kg) orally for 14 days. In the intervention study, another set of 30 male Swiss mice distributed into 5 groups (n = 6) received normal saline, MSG (8 g/kg) alone or in combination with JB (5, 10 and 20 mg/kg) orally, for 14 days. Memory and locomotor functions as well as brain oxido-nitrergic stress biomarkers were then assessed in both studies. The hepatic oxido-nitrergic stress biomarkers, liver enzymes functions and histomorphology of the liver were also assessed. MSG (2, 4 and 8 g/kg) produced memory dysfunction, hyperlocomotion, increased malondialdehyde and nitrite levels accompanied by decreased antioxidant status in the brain and hepatic tissues. MSG-treated mice had increased hepatic enzyme activities (alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase) and distorted cyto-architectural integrity of the liver. These findings further suggest that MSG compromised hepatic functioning, which might also contribute to its neurotoxicity. However, JB (5, 10 and 20 mg/kg, p.o) attenuated the memory deficit, hyperlocomotion, increased oxido-nitrergic stress responses in the brain and hepatic tissues induced by MSG (8 g/kg, p.o). JB also normalized hepatic enzymes activities and histomorphological changes in MSG-treated mice. Taken together, JB mitigated MSG-induced toxicity through mechanisms relating to enhancement of cellular antioxidant-machineries and normalization of hepatic enzymatic functions.

An Interesting Tour of New Research Results on Umami and Umami Compounds

Knowledge about the fifth basic taste, the umami taste, has been investigated by many scientists in the last years and continues to gain importance. Therefore, a lot of scientific studies were conducted to explore several effects influencing the mechanism of umami, which is elicited and enhanced by defined concentrations of MSG (monosodium glutamate) and umami compounds. This paper covers the most relevant scientific literature regarding umami, its use as a flavor enhancer, and the latest umami compounds, which have been released in the last ten years. The main goal of this overview was to summarize the most important results which were related to umami as one of the five basic tastes, the umami taste receptor, the essential role of umami in a great number of physiological mechanisms, and the MSG symptom complex. Furthermore, the function of umami in the interaction of taste, aftertaste and olfactory pathways has been discussed.