Going green

Ecology and sustainability are pillars of the new economy. Governments worldwide are pushing for sustainability, while consumers are demanding sustainable products. To keep pace with these changes, the cosmetics industry, on its part, has started expanding its green vision1 to the supply chain to embed sustainability throughout product lifecycles. Over the last few years, the industry’s efforts have spawned new natural alternatives to traditionally used ingredients. One such ingredient that is receiving considerable attention is bakuchiol, an extract from seeds of Psoralea corylifolia, a plant native to India (locally known as ‘babchi’).

Bakuchiol, being a plant-based extract, is seen as a sustainable alternative to synthetic retinol; the gold standard in skin restoration therapy. It is generally categorised as a ‘bioretinol’ due to its natural plant-based origins. According to studies2, bakuchiol stimulates collagen receptors in the skin, showing promising anti-ageing, anti-inflammatory, and antibacterial properties3. These studies show that the ingredient is as effective as retinol in removing fine wrinkles and improving skin colour, albeit with lesser side effects of peeling and burning, usually associated with retinol. 

While bakuchiol may be good for the skin, like most active molecules, the potential benefits cannot be fully realised unless they are delivered into the deeper layers of the skin. However, getting an active molecule to penetrate in sufficient quantities through the Stratum Corneum (SC), the outer skin layer, is challenging. Here’s why:

The SC layer in the skin functions as an epidermal barrier. Its role includes maintaining water content and balance (permeability barrier), preventing transepidermal water loss (TEWL), defending against microbes and antigens (antimicrobial barrier and immune response barrier), protecting against ultraviolet (UV) light exposure (photoprotection barrier), and guarding against oxidative stresses (antioxidant barrier)4. 

The SC has a unique structure comprising an arrangement of hydrophilic keratin proteins densely packed with hydrophobic lipids. This unique structure however, also makes it difficult for active molecules to penetrate transdermally5. Thankfully, for effective transdermal delivery of bioactives, novel approaches have been developed to design efficient transdermal drug delivery systems. 

Nanoemulsions

Nanoemulsions or “soft” lipid formulations have been shown to improve penetration of drugs and other active agents via the SC and into deeper layers of skin, leading to prolonged cargo release in transdermal delivery. Scientists recently used nanotechnology to engineer a novel oil-in-water colloidal nanoemulsion platform for the transdermal delivery of bakuchiol with promising results6. The study was published in the International Journal of Molecular Sciences. 

In the study, scientists extracted bakuchiol using modern production methods like supercritical fluids-assisted technology (SCF) based 
on ‘Green Chemistry’ principles. SCF is environment-friendly and solvent-free7. 

The nanoemulsion was fabricated by accessing sustainable materials from renewable sources, namely, coco-betaine obtained from coconut oil and surfactin molecules synthesised from rapeseed oil. The resulting formulation was a water-dispersible and kinetically stable bakuchiol formulation. It showed excellent skin biocompatibility and improved skin permeability. The formulation also displayed anti-ageing, moisturising, and skin-restoring abilities. 

The study8 concluded that the novel delivery formulation is a sustainable alternative to conventional retinol products, with a more ecological nature and less harmful effects such as skin irritation, photosensitivity, and health concerns.