INTRODUCTION
Acne is an inflammatory condition common in adolescents, but blemish-prone skin can persist into adulthood.1,2 The pathogenesis of acne is characterized by increased sebum production, follicular hyperkeratinization, C. acnes colonization, and inflammation, which manifest as inflammatory and noninflammatory acne lesions. Acne is believed to have an underlying genetic component, but it can be influenced by a wide variety of factors including age, gender, ethnicity, hormones, diet, pollution, climate, and stress.3-7
A link has been proposed between sebum and acne, with sebum oxidation perhaps contributing to enhanced formation of lesions.8,9 Acneic skin is reported to have both higher levels of oxidative stress and lower levels of antioxidants than healthy skin.10 Additional oxidative environmental factors, such as ultraviolet (UV) radiation and pollution, generate free radicals that exacerbate the condition. Oxidative stress, particularly lipid peroxidation, contributes to inflammation, which creates a favorable environment for acne-causing bacteria (Figure 1). It has been proposed that topical antioxidant application can improve this environment and help reduce the prevalence of acne.11-16
Silymarin is a standardized extract from the seeds of the milk thistle plant (Silybum marianum) which typically contains 70% to 80% of an isomeric mixture of flavonoid complexes called flavonolignans. The main flavonolignans comprising silymarin are silybin, isosilybin, silychristin, dehydrosilybin, and silydianin, in addition to the flavonoid taxifolin. The highest concentration, comprising roughly 50% to 60% of silymarin, is silybin, which is the major bioactive component of the extract. Silymarin is a powerful antioxidant owing to the complimentary free radical scavenging abilities of the various flavonolignan isomers. As such,
A link has been proposed between sebum and acne, with sebum oxidation perhaps contributing to enhanced formation of lesions.8,9 Acneic skin is reported to have both higher levels of oxidative stress and lower levels of antioxidants than healthy skin.10 Additional oxidative environmental factors, such as ultraviolet (UV) radiation and pollution, generate free radicals that exacerbate the condition. Oxidative stress, particularly lipid peroxidation, contributes to inflammation, which creates a favorable environment for acne-causing bacteria (Figure 1). It has been proposed that topical antioxidant application can improve this environment and help reduce the prevalence of acne.11-16
Silymarin is a standardized extract from the seeds of the milk thistle plant (Silybum marianum) which typically contains 70% to 80% of an isomeric mixture of flavonoid complexes called flavonolignans. The main flavonolignans comprising silymarin are silybin, isosilybin, silychristin, dehydrosilybin, and silydianin, in addition to the flavonoid taxifolin. The highest concentration, comprising roughly 50% to 60% of silymarin, is silybin, which is the major bioactive component of the extract. Silymarin is a powerful antioxidant owing to the complimentary free radical scavenging abilities of the various flavonolignan isomers. As such,
