Reishi

Reishi (Ganoderma lucidum), also known as Lingzhi, is a medicinal mushroom with over 2000 years of use in traditional Chinese medicine, containing over 400 bioactive compounds with immunomodulatory, anticancer, antioxidant, antidiabetic, and neuroprotective properties [PMID:40455062, PMID:35407117].

Ganoderma lucidum is a large, reddish-brown mushroom with a distinctive fan-like appearance, revered in Asia for over two millennia as a tonic for promoting health, restoring vitality, and preventing illness [PMID:39527685, PMID:40455062]. It is a white-rot fungus cultivated through solid substrates or submerged mediums, and is consumed as tea, dietary supplements, powders, and in alcoholic beverages [PMID:40455062, PMID:25794896]. The genus Ganoderma has experienced taxonomic confusion, with the name G. lucidum naively applied to Asian species commonly known as Chinese Lingzhi [PMID:25794896].

In traditional Chinese medicine, Lingzhi has been used for improving health, restoring vitality, preventing illness, and promoting longevity [PMID:39527685, PMID:29344411]. Traditional applications include control of blood glucose levels, modulation of the immune system, hepatoprotection, and bacteriostasis [PMID:22593926]. Bioactive components have been used to treat hepatopathy, chronic hepatitis, nephritis, hypertension, hyperlipemia, arthritis, neurasthenia, insomnia, bronchitis, asthma, gastric ulcers, atherosclerosis, leukopenia, diabetes, anorexia, and cancer [PMID:23557365].

Ganoderma lucidum contains over 400 bioactive compounds, including polysaccharides (α/β-D-glucans), triterpenoids (ganoderic acids, ganoderenic acids, ganoderol, ganoderiol, lucidenic acids), sterols/ergosterol, proteins (LZ-8, LZ-9), nucleosides (adenosine, inosine, uridine), nucleotides (guanine, adenine), alkaloids, peptides, dietary fibers, oligosaccharides, alcohols, phenols, mineral elements, vitamins, and amino acids [PMID:34411377, PMID:40455062, PMID:23557365]. More than 600 chemical compounds have been extracted and identified from Ganoderma, with triterpenes serving as primary components [PMID:36671409]. Ganoderma lucidum polysaccharides (GLP) are the main bioactive component in the water-soluble extracts [PMID:29141563].

GLP exerts immunomodulatory effects by affecting B and T lymphocytes, dendritic cells, macrophages, and natural killer cells, promoting immune organ growth, cytokine release, and immune regulatory functions [PMID:31777013]. Anticancer mechanisms include immunomodulatory, anti-proliferative, pro-apoptotic, anti-metastatic, and anti-angiogenic effects via intrinsic and extrinsic apoptotic pathways, cell cycle arrest, telomerase inhibition, autophagy, and inhibition of NF-κB and AP-1 transcription factors [PMID:29141563, PMID:31777015, PMID:14713328]. Ganoderic acid stimulates immune response, activates the MAP-K pathway, induces cytoprotective autophagy and apoptosis in cancer cells [PMID:38398467]. Anti-osteoporosis effects involve suppression of osteoclast differentiation via the RANKL/RANK pathway and downstream ERK, JNK, and p38 MAPK signaling [PMID:31777023]. Antidiabetic effects are mediated by protecting pancreatic islets, inhibiting protein tyrosine phosphatase 1B, and increasing insulin antibody detection [PMID:31777020]. Ganoderma lucidum spore powder ameliorates colitis by inhibiting MAPK pathway phosphorylation (ERK1/2, p38, AKT) and reducing proinflammatory cytokines [PMID:37830195].

Ganoderma lucidum is generally well tolerated and has not been associated with serum aminotransferase elevations during therapy, but has been implicated in rare single instances of acute liver injury, although in most reports other diagnoses were not adequately excluded [PMID:39527685]. Clinical studies have shown beneficial effects as an adjuvant therapy without obvious toxicity [PMID:29141563]. However, due to availability from different sources, quality standardization is advised [PMID:14713328].

A systematic review suggested G. lucidum may improve chemotherapeutic efficacy and reverse multidrug resistance through inhibition of ATP-dependent transmembrane drug transporters [PMID:29256841, PMID:31777015]. G. lucidum used together with colistin reduced nephrotoxicity, suggesting a protective interaction [PMID:32749099].

The evidence base for Reishi consists predominantly of in vitro, in vivo animal studies, and narrative reviews. Only one meta-analysis/systematic review was identified (radioprotection), which found no clinical trials among eligible studies. One systematic review examined chemotherapy adjunct use. Most anticancer, antidiabetic, anti-inflammatory, and neuropharmacological claims rest on preclinical evidence and expert reviews. The few clinical studies that exist are described as questionable. No Ganoderma-related drugs have been approved by the US FDA. Overall evidence strength is low to moderate, with a significant need for well-designed randomized clinical trials to substantiate therapeutic claims.