Effects of extraction solvents on phytochemicals and bioactivities of Ganoderma lucidum

Ganoderma lucidum is a mushroom cultivated in many Asian countries. This work aimed to explore carotenoids and triterpenoids of the mushroom in Vietnam, and to investigate phenolics, antioxidant properties, inhibitory effect on bovine albumin denaturation, inhibition of alpha-glucosidase and alpha-amylase of its extracts obtained with methanol, ethyl acetate, acetone and water. The results showed that the mushroom contained average 20.30 ug of carotenoids, 488.62 ug of ergosterol and 532.53 ug of ganoderic acid A per g of dried G. ludidum fruiting body. The use of different extraction solvents apparently affected phenolic composition and bioactivities of G. lucidum. The methanolic extract had the highest total phenolic content (113.75 +/- 5.05 mg GAE/g), followed by the acetonic extract. These two solvents also outperformed the others with respect to the extractability on major phenolics in G. lucidum. The methanolic extract generally exhibited the strongest antioxidant activity estimated via ABTS and DPPH assays (33.83 +/- 2.40 and 5.36 +/- 0.47 mg GAE/g, respectively) while the ethyl acetate extract displayed the most potent activity (IC50 = 284.79 ug/mL) to protect bovine albumin from heat-induced denaturation. Extraction with the organic solvents resulted in extracts possessing more potent activity to suppress alpha-glucosidase and alpha-amylase in comparison with water. The research provides more data about phytochemicals and additional evidence of potential health endorsing properties of G. lucidum, which are useful for applications in food and nutraceutical industries as well as development of new therapeutic agents for disease prevention and treatment.