Potential Applications of Phyto-Derived Ceramides in Improving Epidermal Barrier Function

Abstract

The outer most layer of the skin, the stratum corneum, consists of corneocytes which are coated by a cornified envelope and embedded in a lipid matrix of ordered lamellar structure. It is responsible for the skin barrier function. Ceramides (CERs) are the backbone of the intercellular lipid membranes. Skin diseases such as atopic dermatitis and psoriasis and aged skin are characterized by dysfunctional skin barrier and dryness which are associated with reduced levels of CERs. Previously, the effectiveness of supplementation of synthetic and animal-based CERs in replenishing the depleted natural skin CERs and restoring the skin barrier function have been investigated. Recently, however, the barrier function improving effect of plant-derived CERs has attracted much attention. Phyto-derived CERs (phytoCERs) are preferable due to their assumed higher safety as they are mostly isolated from dietary sources. The beneficial effects of phytoCER-based oral dietary supplements for skin hydration and skin barrier reinforcement have been indicated in several studies involving animal models as well as human subjects. Ingestible dietary supplements containing phytoCERs are also widely available on the market. Nonetheless, little effort has been made to investigate the potential cosmetic applications of topically administered phytoCERs. Therefore, summarizing the foregoing investigations and identifying the gap in the scientific data on plant-derived CERs intended for skin-health benefits are of paramount importance. In this review, an attempt is made to synthesize the information available in the literature regarding the effects of phytoCER-based oral dietary supplements on skin hydration and barrier function with the underlying mechanisms.

Moisturizers versus Current and Next-Generation Barrier Repair Therapy for the Management of Atopic Dermatitis

“…It should be noted that some popular over-the-counter moisturizers also include a skin-identical or synthetic ceramide, or pseudoceramide [7]. Although these ceramides, if provided at sufficient concentrations, can improve epidermal permeability barrier and SC hydration [8], their content in most formulations is usually too low to impart measurable benefits.…”

Age- and Diabetes-Related Changes in the Free Fatty Acid Composition of the Human Stratum Corneum

“…Keratinocytic lipid synthesis is mostly an autonomous process and produces not only cholesterol and cholesterol derivates but also free fatty acids (FFAs) with different chain lengths as well as triglycerides [14]. Additionally, ceramides (CERs) are synthesised in the endoplasmic reticulum of the keratinocytes, and their anisometric molecular structure differs markedly from other lipid classes [15,16]. Due to load differences within their long-chain molecules, CERs are able to spontaneously form lyotropic mesophases (also known as liquid-crystalline membrane structures) [17,18].…”

Atopic Patients Show Increased Interleukin 4 Plasma Levels but the Degree of Elevation Is Not Sufficient to Upregulate Interleukin-4-Sensitive Genes

“…However, the precise roles of pro-inflammatory leukotrienes [32] and anti-inflammatory lipoxins/resolvins [33, 34] in atopic diseases are not completely understood. A recent study reported that patients suffering from atopic dermatitis show an altered profile of lipids in blood plasma [35] and in the skin [36] and these data have been suggested to point towards an increased production of ALOX-derived pro-inflammatory mediator [35]. IL-4 has previously been identified as regulator of the ALOX pathway in monocytes/macrophages and dendritic cells [21, 22, 37], and microarray-based expression profiles suggested that IL-4 strongly upregulates the expression of ALOX15 and ALOX15B [21, 22, 37, 38].…”