Design and Engineering of “Green” Nanoemulsions for Enhanced Topical Delivery of Bakuchiol Achieved in a Sustainable Manner: A Novel Eco-Friendly Approach to Bioretinol

Abstract

In the present work, we establish novel “environmentally-friendly” oil-in-water nanoemulsions to enhance the transdermal delivery of bakuchiol, the so-called “bioretinol” obtained from powdered Psoralea corylifolia seeds via a sustainable process, i.e., using a supercritical fluid extraction approach with pure carbon dioxide (SC-CO2). According to Green Chemistry principles, five novel formulations were stabilized by “green” hybrid ionic surfactants such as coco-betaine—surfactin molecules obtained from coconut and fermented rapeseed meal. Preliminary optimization studies involving three dispersion stability tests, i.e., centrifugation, heating, and cooling cycles, indicated the most promising candidates for further physicochemical analysis. Finally, nanoemulsion colloidal characterization provided by scattering (dynamic and electrophoretic light scattering as well as backscattering), microscopic (transmission electron and confocal laser scanning microscopy), and spectroscopic (UV–Vis spectroscopy) methods revealed the most stable nanocarrier for transdermal biological investigation. In vitro, topical experiments provided on human skin cell line HaCaT keratinocytes and normal dermal NHDF fibroblasts indicated high cell viability upon treatment of the tested formulation with a final 0.02–0.2 mg/mL bakuchiol concentration. This excellent biocompatibility was confirmed by ex vivo and in vivo tests on animal and human skin tissue. The improved permeability and antiaging potential of the bakuchiol-encapsulated rich extract were observed, indicating that the obtained ecological nanoemulsions are competitive with commercial retinol formulations.

Bakuchiol – a natural meroterpenoid: structure, isolation, synthesis and functionalization approaches

“…Extraction of bakuchiol with advanced methods was rarely explored. A study on ultrasonic assisted 23 and supercritical CO 2 extraction 24 of bakuchiol reported highest yield when compared with other conventional methods. Further, many advanced extraction techniques (microwaves, ultrasonic, pressurized liquids, supercritical fluids, and electric fields etc. )…”

Applications of bakuchiol in dermatology: Systematic review of the literature

“…When compared to other compounds derived from P. coryliforia , (BAK, 8‐MOP, ipsoralen, and psoralidin) in an in vitro study, BAK showed moderate keratinocyte antiproliferative activity, with MOP and ipsoralen with the highest counts 16 . Additionally, BAK was shown to be highly lipophilic, for which an oil‐in‐water nanoemulsion was developed to enhance its transdermal delivery 17 …”

“…16 Additionally, BAK was shown to be highly lipophilic, for which an oil-in-water nanoemulsion was developed to enhance its transdermal delivery. 17 Bakuchiol was also studied to elucidate its immunomodulatory and anti-inflammatory mechanisms in macrophage cell lines, showing that it significantly suppressed the pro-inflammatory cytokine expression in a dose-dependent manner. 18 Also, oral administration per healthy mice significantly decreased delayed hypersensitivity responses as compared to control group.…”

Development of a new chromatographic method for the determination of bakuchiol in cosmetic products

“…To produce cosmetics containing bakuchiol is used bakuchiol carrier oil or about 90% pure bakuchiol which is achieved through an extraction process. Bakuchiol extract purification 4 , 6 , 15 involves several different steps and is not always completely effective. Up to now, a few methods based on high-performance liquid chromatography (HPLC) with various types of detection have been developed for bakuchiol determination in Psoralea corylifolia 4 , 16 – 22 .…”