Capsaicin is a spicy ingredient found in chili peppers. By binding to capsaicin receptors, it can increase the concentration of calcium ions in cells, causing neurons and their fibers to release multiple neuropeptides. It has anti-inflammatory, analgesic, vasodilatory, gastroprotective, and anti-tumor effects.
Capsaicin has various pharmacological and physiological activities, affecting the sensory nervous system containing P-substances, cardiovascular system, body temperature regulation, and gastrointestinal function. It also has anti-inflammatory, analgesic, antipruritic, fat metabolism promoting, and gastrointestinal protective effects. Its most prominent feature is its unique long-term analgesic effect. In clinical use, it is used to treat post-herpetic neuralgia, sciatica, diabetic neuropathy, etc. Furthermore, it has a significant therapeutic effect on preventing elderly people from inhaling pneumonia, low back pain, hematuria syndrome, and psoriasis.
Studies have shown that the side chain of capsaicin is quite sensitive to oxidase. When capsaicin was co-incubated with ADPH and the phenobarbital-treated mouse liver S9 fraction, the side chain of capsaicin could be hydroxylated.
Research has found that the cytochrome peroxidase in the liver can convert capsaicin into phenyloxy, which then dimerizes or forms a covalent bond with cytochrome peroxidase, causing it to lose activity. Therefore, capsaicin can also be used as an inhibitor. Some scholars have studied the electronic oxidation changes of capsaicin using electrochemistry, enzymes, and chemical methods.
Capsaicin can be kept warm with mitochondria or form 5,5-cis-capsaicin by non-enzyme-catalyzed interaction with potassium ferricyanide. It is believed that the mutagenic effect of capsaicin is due to the formation of phenyloxy. This phenyloxy group is very common in the metabolism of many plant polyphenols and plays an important role in the formation of lignin. When tyrosine is oxidized by horseradish peroxidase, the tyrosine dimer is formed, and it is reported that this is caused by the formation of the phenyloxy group. Similarly, when capsaicin is co-incubated with peroxidase and hydrogen peroxide, a fluorescent dimer can be formed.
When capsaicin-like substances are fed in oral form, they are first absorbed by the intestine, mainly metabolized in the liver, and finally enter the systemic circulation. Therefore, the capsaicin-like substances absorbed by the intestine to the central nervous system and other tissues are almost exclusively in the form of their degradation products.
The mechanism of action is through regulating the metabolism of carcinogens and mutagens in vivo and their interaction with target DNA. Capsaicin can inhibit the activity of cytochrome P450 hydroxylase, thereby regulating the metabolism of many carcinogenic polycyclic hydrocarbons, including benzo(a)pyrene. Capsaicin can inhibit the metabolism of [a]-benzo(a)pyrene and its covalent binding with DNA molecules in human and mouse keratinocytes.
Capsaicin is a spicy ingredient found in chili peppers and is a commonly used seasoning and food additive in households. Due to the broad distribution of capsaicin receptors in the body and its involvement in many physiological and pathological processes, it has the potential to become a treatment for pain relief, anti-inflammatory, inducing tumor cell apoptosis, lowering blood pressure, and certain epithelial growth disorders. Capsaicin has now been developed into cream and film for clinical use. It is believed that in the near future, the molecular biology mechanisms of capsaicin will be further clarified; how to use biotechnology such as genetic engineering to develop multiple dosage forms of capsaicin for clinical use will become an important direction for new drug development.