Oral Administration of Lingzhi or Reishi Medicinal Mushroom Ganoderma lucidum (Agaricomycetes) Extract Protects Gingival Tissues against Proinflammatory TNF-α and Oxidative Stress in Periodontitis Model Rats

Ganoderma lucidum is a medicinal mushroom that has been used since ancient times. We studied whether chronic oral administration of G. lucidum extract withstands increases in levels of proinflammatory TNF-α and lipid peroxide (LPO), an indicator of oxidative stress, in the gingival tissues of periodontitis model rats. G. lucidum extract was initially examined for inhibition of in vitro oxidative stress, produced by Fenton's reagents in whole homogenates of fresh gum tissues from rats. Prior to in vivo and in vitro experiments with rats, G. lucidum extract was quantitatively tested for its total polyphenol and/or flavonoid contents and ability to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH)-free radicals. Chronic oral administration of G. lucidum extract (300 mg/kg BW) significantly decreased TNF-α and LPO levels in the gingival tissues of periodontitis model rats. G. lucidum extract also inhibited (P < 0.05) in vitro oxidative stress, as indicated by reduced levels of LPO in G. lucidum extract-preincubated gum tissue homogenates of fresh rats. The in vitro results were, thus, consistent with the in vivo inhibition of lipid peroxidation, DPPH free radical-scavenging effects, and the presence of total polyphenols/flavonoids in G. lucidum extract. Our results provide the evidence, at least partially, for the beneficial effects of G. lucidum on periodontitis, an inflammatory condition of gums which is associated with oxidative stress and preceded by infectious gum diseases.