Diterpenoids have a total of 20 carbons, and (C5H8)n is a structural formula. Diterpenoids are widely distributed in nature, and there are dioxins in plants, animals and marine organisms. There are 119 kinds of skeletons in the diterpenoids, and there are more than 10,000 compounds. The main diterpenoid skeleton types are cleordane, kaurane, labdane, and abietane, among which enantiomer-kaurane compounds are more. Diterpenoids isolated from various plants have biological activities such as antibacterial, anti-tumor and anti-oxidation effects.
Diterpenoid structures are classified into acyclic (chain), monocyclic, bicyclic, tricyclic, tetracyclic and pentacyclic groups according to the number of carbon rings in their molecules.
Chain diterpenoids: a plant alcohol widely present in chlorophyll, which is a raw material for the synthesis of vitamin E and vitamin K1.
Monocyclic diterpene: Vitamin A, mainly in cod liver oil.
Bicyclic diterpene: Ginkgolide is the active ingredient in the root bark and leaves of Ginkgo biloba. It is the main active ingredient of Ginkgo biloba preparation for treating cardiovascular and cerebrovascular diseases. Andrographolide in Andrographis paniculata is the main component of anti-inflammatory and anti-inflammatory of Andrographis paniculata.
Tricyclic diterpenoids: Tripterygium wilfordii, triptolide and 16-hydroxytriptolide are anti-cancer active substances isolated from Tripterygium wilfordii. Taxol is mainly isolated from Taxus and has many anticancer activities.
Tetracyclic diterpenoids: Stevioside in Stevia rebaudiana, which is 300 times sweeter than sucrose and has high sweetness and low calorie. Recently, however, stevioside has been reported to be carcinogenic and banned in the United States and the European Union.
The anti-tumor mechanisms of diterpenoids include: (1): Diterpenoids induce apoptosis of tumor cells by modulating signaling molecules associated with the apoptotic pathway. (2) Diterpenoids inhibit the abnormal proliferation of tumor cells. (3) Direct cytotoxicity: Some diterpenoid compounds can directly exert a killing effect on tumor cells, and avoid the apoptosis process in this segment. (4) Inhibition of tumor angiogenesis: Diterpenoids have a certain inhibitory effect on tumor angiogenesis, thereby inhibiting blood supply to tumors and causing death of tumor cells by ischemia and hypoxia. (5) Decrease mitochondrial membrane potential in tumor cells: Mitochondria efficiently store and convert energy for the body and regulate cell survival. (6) Change the concentration of free calcium ions in tumor cells.
In addition to anti-tumor, anti-viral, anti-inflammatory and anti-immunological activities, diterpenoids have other biological activities, such as anti-angiogenesis and significant antihypertensive effects, and have a relaxing effect on a variety of isolated vascular smooth muscles. In addition to its strong anti-tumor activity, Lanchong Tea A has anti-platelet aggregation and is of great significance in preventing arterial thrombosis and arteriosclerosis. Further, most enantiomeric-kaurane compounds have varying degrees of antioxidant activity. High concentration of caraway A has weak selective inhibitory effect on thromboxane A2 synthesis, while caraway A has anti-carbon tetrachloride liver injury and anti-myocardial ischemia-reperfusion injury. The enantioseparacetane diterpenoids isolated from non-caraway genus plants has the same physiological activity as the genus Camellia, but also in the antispasmodic, anti-vascular smooth muscle, anti-platelet aggregation, anti-AIDS, and anti-virus, etc. In addition to this, some diterpenoids have an anti-parasitic infection.