Natural antioxidants
Vitamin C and vitamin E were the first antioxidants to be applied. In animal tests and in vitro tests, vitamin C and vitamin E showed scavenging of free radicals, protection of endothelial cells, and inhibition of inflammatory factors associated with atherosclerosis (e.g., monocyte chemotactic factor-1, cell adhesion molecule-1, interleukin-6, and tumour necrosis factor-𝝰). These phenomena ignited hopes for the application of antioxidants in the treatment of atherosclerotic cardiovascular diseases. Therefore, since the second half of the last century, Heart Outcome Prevention Evaluation (HOPE), Primary Prevention Project (PPP), Chloseterol Lowering Atherosclerosis Study (Chloseterol) have been conducted. The Chloseterol Lowering Atherosclerosis Study (CLAS) and other large randomised controlled trials have been conducted to verify the clinical benefits of natural antioxidants (vitamin C, vitamin E, multivitamins) in cardiovascular disease: whether they can actually slow down the progression of atherosclerosis and reduce clinical vascular events. However, the results of the clinical studies were disappointing: the vast majority of the studies failed.
The large number of negative studies led the medical community to believe that antioxidant therapy for atherosclerotic cardiovascular disease was on its last legs. These phenomena have also caused researchers to think, and in 2009 Steinberg, the founder of the oxidative theory of atherosclerosis, pointed out that vitamin E and vitamin C are weak antioxidants and are not effective antioxidants in the body, while the synthetic antioxidant probucol has a long history of proven efficacy.
Synthetic antioxidants
Probucol was first used as a lipid-lowering drug in clinical practice. In recent years, a large number of studies have found it to have powerful antioxidant properties. Unlike natural antioxidants, Probucol is a synthetic anti-oxidative stress agent, which has become a representative antioxidant and is widely used in several clinical areas.
The clinical benefits of Probucol are closely related to its unique structure: (1) Probucol has 14 lipophilic methyl groups and its structure is completely symmetrical, with strong lipid solubility, effectively traversing the tissues, and it can enter the tissues to exert antioxidant effects; (2) It has strong binding ability with lipoproteins, and strongly inhibits oxidative modification of low-density lipoproteins; (3) Probucol has 2 antioxidant active groups -phenolic hydroxyl group, strong antioxidant capacity, and irreversible chain-breaking reaction in the molecular structure after binding with free radicals. These structures determine that Probucol is not only a tissue-type antioxidant, but also a chain-breaking antioxidant with strong and irreversible antioxidant capacity, which can play a strong antioxidant role in the tissues, and a large number of studies have proved that Probucol has a significant clinical effect in the field of atherosclerotic vascular disease, diabetes mellitus, nephropathy, and other clinical treatments.
In recent years, synthetic antioxidant stress drugs have been gaining remarkable results, which has renewed people’s hope for antioxidant therapy.