Imparting mildness with living tea plant ingredient

In this article, Recentia CS is evaluated in in vitro surfactant-induced skin cell inflammation/irritation model to determine if this ingredient has potential to reduce undesirable impact of personal care and cleansing products. Cultured human epidermal keratinocytes (HEK) were treated with surfactants to induce release of key inflammatory cytokine interleukin (IL-1) and key chemokine interleukin (IL-8). Cytotoxicity was evaluated with Lactate Dehydrogenase (LDH) assay. Based on cytotoxicity data and abilities to induce release of IL-1, six representatives of four different classes of surfactants were ranked. A nonionic ethoxylated alcohol was the mildest surfactant and was able to induce release of IL-1but not IL-8. It was found that Recentia CS was a potent inhibitor of IL-1and IL-8 in HEK treated with either Sodium Dodecyl Sulfate (SDS) or ethoxylated alcohol. Activity of Recentia CS was comparable to 2-acetoxybenzoic acid (positive control for IL-1) for inhibition of IL-1induced by either SDS or ethoxylated alcohol. The 2-acetoxybenzoic acid was ineffective for inhibition of IL-1induced by ethoxylated alcohol. Importantly, Recentia CS inhibited both SDS-induced and basal level IL-8 in keratinocytes, while SB203580 (positive control for IL-8) inhibited SDS-induced IL-8 only. Traditional green tea and black tea preparations obtained from the same cultivar as Recentia CS failed to inhibit IL-1and IL-8 induced by either SDS or ethoxylated alcohol. Thus, Recentia CS provides not only superior multifunctional antioxidant and anti-inflammatory activities, as well as photo-stabilisation properties, but also significantly imparts mildness to novel personal care and cleansing products by mitigating surfactant-induced skin inflammatory and irritation responses.

 Surfactants are used in a variety of personal care and cleansing products to allow or improve processes of cleansing, foaming, emulsifying, solubilising, and dispersing. Repetitive contact with surfactant-containing products has been shown to cause damage of the skin barrier due to surface or interface activities of the surfactants.1 The weakened barrier subsequently leads to deeper penetration of the surfactants into skin and induced irritation and inflammation,2,3 which can be perceived by consumers as dryness, itchiness, swelling, redness, and pain. As surfactants are widely used in hand soaps, facial and body washes, shampoos and conditioners, as well as dish, laundry and housecleaning detergents, human skin contact with surfactants is frequent. Therefore, mitigating surfactant-induced skin inflammatory responses is highly desirable. One of the methods to study and quantify such inflammation is by culturing cells of the tissue most likely to come in contact with surfactants, such as viable epidermal keratinocytes from human skin. Keratinocytes have become the focus of attention in irritant-induced skin inflammation by virtue of their epidermal location, importance in maintaining the integrity of the stratum corneum barrier, and the ability to produce a variety of inflammatory mediators.4 Keratinocytes contain interleukin (IL)-1, one of the primary cytokines which can be additionally induced and released at an early stage of inflammation cascade in response to a range of irritants including surfactants. Subsequently, IL-1induces numerous down-stream inflammatory mediators, such as signalling molecules, cytokines and chemokine IL-8, which critically contribute to skin morphological changes and development of the signs of skin inflammation and irritation. Therefore, by reducing keratinocytes’ release of the initial inflammatory response mediator (IL-1) and the key chemotactic factor (IL-8), the signs of the skin irritation and inflammation may be reduced, prevented, and eliminated. Recentia CS is obtained from living Camellia sinensis (tea) plants via patented Zeta Fraction technology.5–7 Unlike the traditional green tea and black tea, Recentia CS preserves a unique and diversified composition of natural constituents and exhibits superior multifunctional benefits. In the articles previously published in Personal Care Europe magazine,8,9 we have presented and discussed potent antioxidant, photostability, and anti-inflammatory properties of novel ingredients that are well-suited to personal care (Recentia CS) and for ‘Beauty From Within’ beverage (Purecentia) products. This paper encompasses the continuing research regarding utilisation of the power of living tea plant for meeting consumers’ growing demands for personal care and cleansing products that are milder to the skin and hair. We evaluated Recentia CS (now referred to as ‘the tea plant serum fraction’) in a surfactant-induced skin keratinocyte inflammation model and demonstrated that the tea plant serum fraction may provide a novel approach to develop milder products.

Materials and methods