The fact that ubiquinone can serve not only as an energy generator but also as an antioxidant in the skin has been investigated (168,169). In cultured human keratinocytes exposed to hydrogen peroxide, the detrimental increase in the activity of phosphotyrosine kinase was suppressed and the loss of glulathione was prevented (169). Ubiquinone (0.3%) also suppressed […]

Background Ubiquinone (coenzyme Q10, Figure 14) is so named because it is ubiquitous in virtually all living cells, excluding some bacteria and fungi, although the level is quite variable. Since most human tissues synthesize ubiquinone, it is not considered to be a vitamin. Ubiquinone is primarily located in the inner mitochondrial membrane where it is […]

To evaluate possible improvement to photodamage, a split-face study was done on 33 women (162). Topical application twice daily of 5% lipoic acid cream for 12 weeks decreased skin roughness by 50.8% (as measured by laser profilometry) when compared with the placebo. Clinical and photographic evaluation showed reduction in lentigenes and fine wrinkles in this […]

a-LA has been found to penetrate rapidly into murine and human skin to dermal and subcutaneous layers. Two hours after application of 5% a-LA in propylene glycol, maximum levels of a-LA were attained in the epidermis, dermis, and subcutaneous tissue (154). The stratum corneum concentration of a-LA predicted the penetration and levels in the underlying […]

Topical a-LA with its metabolite DHLA could protect the skin from oxidative stress in several ways. Both a-LA and DHLA are highly effective antioxidants, as summarized in Table 1 (22). DHLA is actually the more potent form. Both successfully scavenge ROS in vitro and in vivo. However, pro-oxidant activity has been observed. This occurs when […]

R-Alpha lipoic acid (a-LA) is synthesized in the mitochondria of plants and animals, including humans. Natural a-LA is covalently bound to proteins via lysine; thus only minimal free a-LA enters the circulation after biosynthesis or eating a-LA-rich food (22). The lipoamide is a required co-factor for two enzymes in the citric acid cycle. It is […]

As described above, topical 5 mmol genistein has been studied extensively and has been proven to protect from UV damage. Unlike vitamin C, genistein is a stable molecule. Unlike vitamin E and Se, genistein is absorbed transcutaneously to give protective activity. The only challenge in formulation is to have a pure source of genistein without […]

The mechanism by which genistein inhibits carcinogenesis may be through inhibition of tyrosine protein kinases, the enzymes which phosphorylate proteins necessary for the regulation of cell division and transformation (132). Of particular importance is phosphorylation of TPK-dependent epidermal growth factor receptors which are related to tumor promotion, including initiation of transcription factors, release of inflammatory […]

Genistein is an isoflavone isolated from soy, the structure of which is shown in Figure 7. Recent interest in genistein has been stimulated by epidemiological studies which correlate diets high in soy with reduced incidence of cardiovascular disease (123), osteoporosis (123), and certain cancers in humans (124-126). The direct anticarcinogenic action of genistein is documented. […]