Orobol, a derivative of genistein, inhibits heat-killed Propionibacterium acnes -induced inflammation in HaCaT keratinocytes.

Acne is a chronic skin disease that typically occurs in the teens and twenties, and its symptoms vary according to age, sex, diet, and lifestyle. Acne is characterized by hyperproliferation of keratinocytes in the epidermis, sebum overproduction, growth of Propionibacterium acnes , and P. acnes induced skin inflammation. Interleukin (IL)-1α and IL-6 are predominant in the inflammatory lesions of acne vulgaris. These cytokines induce an inflammatory reaction in the skin in the presence of pathogens or stresses. Moreover, IL-1α accelerates the production of keratin 16, which is typically expressed in wounded or aberrant skin, leading to abnormalities in architecture and hyper-keratinization. 3',4',5,7-Tetrahydroxyisoflavone, also termed orobol, is a metabolite of genistein. Orobol inhibited the P. acnes induced increases in IL-6 and IL-1α levels in human keratinocytes (HaCaTs) compared with salicylic acid. In addition, orobol decreased the IL-1α and IL-6 mRNA levels and inhibited the phosphorylation of inhibitor of kappa-B kinase, nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha, and mitogen-activated protein kinase induced by P. acnes . Finally, the expression of Ki67 was decreased by orobol. Thus, orobol ameliorated the inflammation and hyper-keratinization induced by heat-killed P. acnes and thus has potential for use in foods and cosmetics.