Effect of combination of germinated brown rice and oyster mushroom on the inflammatory response and glycemic control in hyperglycemic aged rat model

The elderly are a high-risk age group that is more vulnerable to severe diseases, such as diabetes, cardiovascular disease, and respiratory tract infections. Germinated brown rice (GBR) has glucose-lowering properties and antioxidant potential due to high phenolic bioactive compounds. Oyster mushroom (Pleurotus oestreatus) is rich in β-glucans with its wide-known anti-inflammatory effect. This present study evaluated the effect of the combination of GBR and oyster mushroom supplementation in the inflammatory response and glycemic effect on aged rats. Supplementation was given at 250 mg per kg body weight per day in three different ratios and administered to fructose-induced hyperglycemic aged rats for 8 weeks. A total of thirty-five rats aged 12-18 months were randomly assigned into five groups, negative (I) and positive (II) control, GBR: oyster mushroom ratio extract of 60%:40% (III), 70%:30% (IV), and 90%:10% (V). Groups II to IV received 50% fructose in the drinking water. The inflammatory and glycemic responses were evaluated by measuring serum TNF-α, IL-6, fasting glucose and insulin. HOMA-IR and HOMA-β were also calculated. All supplementation formulations had not been able to show a significant reduction in the levels of pro-inflammatory markers as well as fasting insulin markers. However, this formulation was able to reduce the serum glucose level (p = 0.001) and insulin resistance level (p = 0.002) of hyperglycemic rats to a similar level as the negative control rat. No significant difference was found between the three different formulations. In summary, the combination of GBR and oyster mushroom supplementation has the potential as functional food for the management of hyperglycemia and its possible complications.