Do Ganoderma Species Represent Novel Sources of Phenolic Based Antimicrobial Agents?

Ganoderma species have been recognized as potential antimicrobial (AM) agents and have been used in traditional Chinese medicine (TCM) for a long time. The aim of this study is to examine the AM potential of autochthonous Ganoderma species (G. applanatum, G. lucidum, G. pfeifferi and G. resinaceum) from Serbia. The extraction of fungal material was prepared in different solvents (ethanol-EtOH, water-H2O, chloroform-CHCl3). Antibacterial activity (ABA) was determined using disk-diffusion, agar-well diffusion, and micro-dilution method, while for antifungal properties disk-diffusion and pour plate method were applied. Antiviral activity was tested on model DNA virus LK3 and determined by plaque assay. Statistical PCA analysis was applied for detection of correlation effects of phenolics and AM activities, while LC-MS/MS was performed for phenolics quantification. G. resinaceum CHCl3 extract expressed the most potent ABA against P. aeruginosa (MIC = 6.25 mg/mL), probably due to presence of flavonoids and 2,5-dihydroxybenzoic acid. Among H2O extracts, the highest ABA was determined for G. pfeifferi against both E. coli and S. aureus (21 and 19 mm, respectively). EtOH extracts of G. pfeifferi and G. resinaceum were the most effective against A. niger (23.8 and 20.15 mm, respectively), with special impact of phenolic acids and flavonoid isorhamnetin, while C. albicans showed the lowest susceptibility. The most potent antiviral inhibitor was G. lucidum (70.73% growth inhibition) due to the high amount of phenolic acids. To the best of our knowledge, this is the first report of a methodical AM profile of G. pfeifferi and G. resinaceum from the Balkan region including PCA analysis.

Mushroom Species Stereum hirsutum as Natural Source of Phenolics and Fatty Acids as Antioxidants and Acetylcholinesterase Inhibitors.

Many lignicolous mushroom species are used as a food supplement and may represent an alternative treatment of Alzheimer's disease (AD). This study aimed to evaluate acetylcholinesterase inhibition (AChEI) of Stereum hirsutum together with antioxidant activity (AO) and cytotoxic activity against HepG2 cells. Different extracts (water, ethanol, methanol, polysaccharide) were analyzed, with respect to their mineral composition and chemical content. Ethanol extract was the most potent in AChEI (98.44 %) and demonstrated cytotoxic activity (91.96 % at 900.00 µg/mL), while the highest AO was demonstrated for polar extracts (methanol and water) as well. These activities may be attributed to determined phenolics (hydroxybenzoic and quinic acid) and fatty acids (FA), while biflavonoid amentoflavone may be responsible for cytotoxic activity. The most prevalent FA was linoleic (40.00 %) and the domination of unsaturated FA (UFA) (71.91 %) over saturated (26.96 %) was observed. This is the first report of AChEI of S. hirsutum extracts and first detection of amentoflavone. Due to high amount of UFA and well-expressed AChEI, this species can be considered as a potent food supplement in the palliative therapy of AD.