Biosynthesis, Gene Expression, and Pharmacological Properties of Triterpenoids of Ganoderma Species (Agaricomycetes): A Review

For more than 6 millennia, Ganoderma species have been used in traditional Asian medicine due to their health benefits. Ganoderma synthesizes several compounds with biological activity, including lanostane-type triterpenoids like ganoderic acids (GAs), lucidones, and colosolactones. These triterpenoids have been investigated for their antiviral, hypoglycemic, and anticancer effects. GAs are highly oxygenated triterpenoids with different functional groups attached to lanostane skeleton. Their great chemical diversity makes GAs prospects for the development of new drugs to treat multiple illnesses such as cancer. The effect of GAs against cancer cells has been associated with their capability to inhibit specific targets such as STAT3, to induce apoptosis and cell cycle blockage, and to increase natural killer cell activity. Due to the biological activity of these molecules, novel strategies are being developed for Ganoderma production mainly by liquid cultivation, gene overexpression (HMGR, SQS, LS) by elicitors, and modified growing conditions (carbon and nitrogen sources, pH, temperature), which induce reactive oxygen species production, key compounds for secondary metabolism. In addition, some transcription factors are mainly expressed under stress conditions, such as cytochrome P450 genes, which participate in the regulation of triterpenoid synthesis. The fermentation process has been scaled up to a 300-L bioreactor, which shows good GA production. This article reviews current knowledge on bioactive triterpenoids of Ganoderma and their production, biosynthesis, and pharmacological properties, emphasizing gene expression in liquid culture. It also discusses the lack of information regarding other species with high potential.