Writing in its international patent, Unilever said its method centred on external application of hydroxystearic acid and various blends of the emollient to induce the secretion of AMPs from keratinocytes on the human body – an “important part” of the skin’s natural defence system. The topical composition worked to kill or inactivate invading infectious microorganisms, such as Staphylococcus aureus [S. aureus], which was associated with various skin and soft tissue infections.
Antimicrobial peptides to the defence
“AMPs are ubiquitous in nature and they typically exhibit a broad spectrum of activity against invading bacteria, fungi, viruses and parasites,” Unilever wrote in its patent filing.
“…The present inventors have found that on application of hydroxystearic acid on skin, which could be skin per se or scalp or oral cavity, the active induces generation of AMPs which is known to be an important step in improving the immunity of the skin against attack by microorganisms.”
These enhanced levels of AMPs on the skin following application, it said, then interacted synergistically with the hydroxystearic acid active to provide antimicrobial activity against infective organisms like S. aureus and P. aeruginosa.
“…Hydroxystearic acid therefore provides protection for the body against infections by boosting the body’s own defence. In other words, the active primes the body surface for germ protection. The advantage of this is that it provides long-lasting protection, e.g. up to 24 hours of protection against germs.”
‘Skin friendly’ with natural molecules
Unilever said hydroxystearic acid had long been used in personal care and cleansing compositions as part of fatty acid mixtures; in cosmetics as an emulsifier; and in industrial applications as a lubricant. However, the company said its use as an active for generation of AMPs on topical surfaces of the body was not known.
The goal of the invention, it said, had been to enhance AMP levels in the skin using natural molecules that were perceived by the consumer to be more “skin friendly” and “less harsh”.
“…The benefit obtained by a consumer is that the skin is protected against germs which may attack in the future by application of a composition comprising hydroxystearic acid.”
Unilever said the topical composition could be used in leave-in or rinse-off products across an array of personal care, hair care, oral care and cosmetic products for non-therapeutic use, including liquids, lotions, creams, foams, soaps, toners, antiperspirants, wipes, and even foundations and lipsticks.
Hydroxystearic acid was preferably included at 0.1-1% by weight of the composition and could be also be blended by antimicrobial peptides (AMPs) or antimicrobial lipids (AMLs).
WIPO International Patent No. WO/2022/117404
Published on: June 9, 2022. Filed on: November 24, 2021.
Title: “Hydroxystearic acid for inducing generation of antimicrobial peptides”
Authors: Unilever – TC. Alexander et al.