In vitro cholesterol lowering activity of Ganoderma australe mycelia based on mass spectrometry, synchrotron Fourier-transform infrared analysis and liver-spheroid bioactivity

Abstract

Mycelia were cultivated from a Thai wild mushroom identified as Ganoderma australe based on polymerase chain reaction (PCR) and morphological analyses. The mycelial extracts were examined for their active ingredients using a liquid chromatography-tandem mass spectrometry (LC‒MS/MS) method. This revealed the presence of lovastatin and tentative compounds including p-coumaric, nicotinamide, gamma-aminobutyric acid, choline, nucleosides, amino acids, and saccharides. The extracts had an inhibitory effect on the activity of HMG-CoA reductase in a concentration-dependent manner. At 2.5 mg/mL, the G. australe extracts did not interfere with the viability of HepG2 spheroids, but their biochemical composition was altered as determined by Fourier-transform infrared (FTIR) spectroscopy. The lipid profile of the spheroids treated with the mycelial extract was distinct from that of the control and the 5 µM lovastatin treatment, corresponding with the production of cholesterol by the spheroids. The mycelia of G. australe increased the percentage of high-density lipoprotein (HDL) production to 71.35 ± 2.74%, compared to the control and lovastatin-treated spheroids (33.26 ± 3.15% and 32.13 ± 3.24%, respectively). This study revealed the superior effect of natural compound mixtures to pure lovastatin, and the potential use of Thailand’s wild G. australe as a functional food to prevent or alleviate hypercholesterolemia.