INTRODUCTION
Psoralea corylifolia is a plant found in the southern United States, India, and China that is used in traditional Chinese and Ayurvedic medicine due to its anti-tumor, anti-bacterial, and anti-inflammatory properties.1 The word Psoralea is derived from the Greek word psoraleos, meaning "affected with the itch or with leprosy,"1 perhaps alluding to the plant's usefulness in dermatologic diseases. Previous uses of P. corylifolia in traditional Chinese medicine include the treatment of psoriasis, leprosy, and eczema.1 Interestingly, the seed powder was commonly mixed with buttermilk and topically applied to treat scabies and ringworm.1
One derivative from the seeds of P. corylifolia is bakuchiol, a meroterpene phenol shown to have anti-microbial, anti-inflammatory, and anti-tumorigenic effects.1,2 Recent studies in mouse models demonstrate bakuchiol has cardioprotective effects after myocardial infarction and can reduce liver fibrosis.3 While these visceral effects of bakuchiol are still early in development, bakuchiol’s use in disorders of the skin is gaining in popularity, especially for the use in acne, and anti-aging products. Herein we describe the in vitro and in vivo evidence of bakuchiol in acne, post-inflammatory hyperpigmentation (PIH), anti-aging, psoriasis, and skin cancer.
One derivative from the seeds of P. corylifolia is bakuchiol, a meroterpene phenol shown to have anti-microbial, anti-inflammatory, and anti-tumorigenic effects.1,2 Recent studies in mouse models demonstrate bakuchiol has cardioprotective effects after myocardial infarction and can reduce liver fibrosis.3 While these visceral effects of bakuchiol are still early in development, bakuchiol’s use in disorders of the skin is gaining in popularity, especially for the use in acne, and anti-aging products. Herein we describe the in vitro and in vivo evidence of bakuchiol in acne, post-inflammatory hyperpigmentation (PIH), anti-aging, psoriasis, and skin cancer.
MATERIALS AND METHODS
Bakuchiol Use in Acne
Bakuchiol has fewer adverse effects than topical retinoids making it a viable alternative for retinoids in patients with sensitive skin. Since it is able to effectively inhibit three pathways involved in the pathogenesis of acne: increased inflammatory mediators, Cutibacterium acnes colonization (formerly known as Propionobacterium acnes), and increased sebum production (Figure 1), it would serve well in the armamentarium of acne therapies.
Anti-inflammatory Effects of Bakuchiol
Bakuchiol's ability to modulate levels of inflammatory mediators makes it an appealing option for the treatment of acne. In studies using murine derived macrophages stimulated with the inflammatory cytokine interferon-γ (IFN-γ) or bacterial lipopolysaccharide (LPS), bakuchiol decreased levels of nitric oxide synthase levels (iNOS).4 iNOS plays a role in activating macrophages in inflammatory states. Furthermore, the researchers demonstrated that the decrease in iNOS expression occurred at a transcriptional level due to bakuchiol's inhibition of nuclear transcription factor-κB (NF-κB),4 a transcription factor responsible for generating inflammatory mediators such as IL-6 and iNOS.4-6 Analysis of punch biopsy samples of acne lesions show elevated levels of NF-κB.7 Bakuchiol's ability to inhibit NF- κB as shown in Pae et al may suggest activity in decreasing downstream inflammatory mediators.
In a mouse model of ear edema, topical bakuchiol significantly reduced levels of the downstream inflammatory
Bakuchiol has fewer adverse effects than topical retinoids making it a viable alternative for retinoids in patients with sensitive skin. Since it is able to effectively inhibit three pathways involved in the pathogenesis of acne: increased inflammatory mediators, Cutibacterium acnes colonization (formerly known as Propionobacterium acnes), and increased sebum production (Figure 1), it would serve well in the armamentarium of acne therapies.
Anti-inflammatory Effects of Bakuchiol
Bakuchiol's ability to modulate levels of inflammatory mediators makes it an appealing option for the treatment of acne. In studies using murine derived macrophages stimulated with the inflammatory cytokine interferon-γ (IFN-γ) or bacterial lipopolysaccharide (LPS), bakuchiol decreased levels of nitric oxide synthase levels (iNOS).4 iNOS plays a role in activating macrophages in inflammatory states. Furthermore, the researchers demonstrated that the decrease in iNOS expression occurred at a transcriptional level due to bakuchiol's inhibition of nuclear transcription factor-κB (NF-κB),4 a transcription factor responsible for generating inflammatory mediators such as IL-6 and iNOS.4-6 Analysis of punch biopsy samples of acne lesions show elevated levels of NF-κB.7 Bakuchiol's ability to inhibit NF- κB as shown in Pae et al may suggest activity in decreasing downstream inflammatory mediators.
In a mouse model of ear edema, topical bakuchiol significantly reduced levels of the downstream inflammatory
