Triterpenoids
Ganoderma Triterpenoids are the most important components in ganoderma because they are species-specific and display bioactive diversity. The first person to discover ganoderma triterpenoids was Japanese researcher whose original intention was to remove the bitter taste of ganoderma.
Triterpenoids are metabolites existing in plants or fungi. The fresh air inhaled while one strolls in the forest contains high levels of triterpenoids, which are also commonly known as phytoncides. Mint, citrus, lavender are rich in triterpenoids and can be refined into essential oils. Most of the components found in these essential oils are called monoterpenes or sesquiterpenes.
(i) Inhibition of Tumor Metastasis Effects
In 2002, Kimura et al. (Japan) presented research showing that mice with lung cancer fed with crude triterpenoids of the ganoderma fruiting body (100mg/Kg, 200mg/Kg), had tumor sizes significantly smaller than those mice in the control group (which is not fed with crude triterpenoids of the ganoderma fruiting body).
Due to lung cancer cell proliferation, the mice in the control group demonstrated liver and spleen metastases, whereas metastases in the group fed with triterpenoids were significantly controlled. This inhibitory effect was proportioned to dosage, higher dosage resulting in higher efficacy. When a malignant tumor is formed as it mutates from cells it will develop new blood vessels in order to obtain nutrients for its growth and expansion of its territory. In medical terms, this phenomenon is called ‘angiogenesis’. Newly-formed vessels connect to other, healthy vessels where the cancer cells can obtain nutrients easily for their proliferation and migration. The main reason why ganoderma triterpenoids are effective in arresting cancer cell metastasis is due to their ability to inhibit the malignant tumor from forming new blood vessels (‘anti-angiogenesis’). Thus, cancer cells can no longer migrate to other organs or tissues via the new vessels, and may undergo apoptosis through lack of nutrition.
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(ii) Protection of the Liver
Statistical analysis of research work conducted over the years indicates that ganoderma triterpenoids have a protective effect on the liver. In 1999, Korean scientists, Kim et al., discovered that, in mouse liver ex-vivo tests, ganoderma triterpenoids could inhibit beta-glucuronidase activity in the liver. Beta-glucuronidase is a blood biochemical index for liver fibrosis. The main compound acting as the inhibitor is ganoderenic acid A isolated from ganoderma triterpenoids.
The potential to protect the liver provides multiple benefits, including reducing hepatic inflammation, increasing the amount of hepatic proteins (generating new liver cells), repairing liver cells to promote regeneration, arresting virus invasion of the liver, assisting liver to form antibodies against viruses and killing hepatoma cells.
(iii) Immune Modulation
An allergic reaction is one of the symptoms of an immune disorder where the immune system over-reacts. Mast cells play an important role in allergic reactions as the histamine they release induces inflammation. In 1986, Japanese researchers, Konda et al., discovered that the four most common triterpenoids from G. lucidum, namely ganoderic A, B, C, D are effective in preventing histamine from being released from mast cells in mice.
Similar results were obtained from research, carried out by Bi-Fong Lin and Miao-Lin Chen of National Taiwan University (NTU) in 2006, which proposed that G.tsugae attenuates the symptoms of respiratory allergy in mice. The purpose of this experiment was to explore its possibility in modulating T cell activity. This research confirmed that ganoderma triterpenoids (separated from YK-01 strain) are the most important factor in effectively preventing T-cells developing into Th2 cells. Th2 cells are imperative in triggering allergy as it is the over-reactive Th2 cells that induce immune disorders.
(iv) Cholesterol Reduction
Research on a cholesterol-lowering drug, developed by the Nestle Research Centre in Switzerland in 2004, showed that ganoderma was effective in reducing cholesterol, especially low density cholesterol, in hamsters and mini pigs with high blood cholesterol. In 2005, an ex-vivo test was conducted to prove that the effective components were ganoderma triterpenoids, including ganoderic alcohol A, B, ganoderic-aldehyde A and ganoderic acid Y.
Two years later, the same research team went a step further in searching for the reasons by using a cell model. The results showed that it was ganoderma triterpenoids that suppressed hepatic cholesterol biosynthesis in the liver. A review of the literature showed that in 1986, Professor Ming-Shi Shiao (Taiwan) used isotopic methods to prove that ganoderic acids could inhibit hepatic cholesterol biosynthesis.
In 1989, Japanese researchers, Komoda et al., obtained similar results using a liver ex-vivo test, finding ganoderic acid C and its derivatives effective in suppressing hepatic cholesterol biosynthesis.
(v) Anti-oxidation
Oxidation in the human body signifies aging, and oxidized cells are more vulnerable to pathological changes. The emergence of a number of anti-oxidants is to effect the slowing down of oxidation in the human body. In 1999, Zhu and co-workers at the Chinese University of Hong Kong conducted an animal ex-vivo test (using rat red blood cells and liver mitochondria), and discovered that triterpenoids of ganoderma possess the most powerful anti-oxidation capability.
Furthermore, ganoderic acid A, B, C, D, lucidenic acid B, and ganodermanontiol were isolated from the anti-oxidation triterpenoids as the active compounds. Its physiological activity, promoting human health, is one of the most important actions of ganoderma. On this basis the Japan Health Food Association (JHFA) uses triterpenoids to authenticate ganoderma products.
