The Herbal Bitter Drug Gentiana lutea Modulates Lipid Synthesis in Human Keratinocytes In Vitro and In Vivo

Abstract

Gentiana lutea is a herbal bitter drug that is used to enhance gastrointestinal motility and secretion. Recently we have shown that amarogentin, a characteristic bitter compound of Gentiana lutea extract (GE), binds to the bitter taste receptors TAS2R1 and TAS2R38 in human keratinocytes, and stimulates the synthesis of epidermal barrier proteins. Here, we wondered if GE also modulates lipid synthesis in human keratinocytes. To address this issue, human primary keratinocytes were incubated for 6 days with GE. Nile Red labeling revealed that GE significantly increased lipid synthesis in keratinocytes. Similarly, gas chromatography with flame ionization detector indicated that GE increases the amount of triglycerides in keratinocytes. GE induced the expression of epidermal ceramide synthase 3, but not sphingomyelinase. Lipid synthesis, as well as ceramide synthase 3 expression, could be specifically blocked by inhibitors of the p38 MAPK and PPARγ signaling pathway. To assess if GE also modulates lipid synthesis in vivo, we performed a proof of concept half side comparison on the volar forearms of 33 volunteers. In comparison to placebo, GE significantly increased the lipid content of the treated skin areas, as measured with a sebumeter. Thus, GE enhances lipid synthesis in human keratinocytes that is essential for building an intact epidermal barrier. Therefore, GE might be used to improve skin disorders with an impaired epidermal barrier, e.g., very dry skin and atopic eczema.

Precision medicine and phenotypes, endotypes, genotypes, regiotypes, and theratypes of allergic diseases

“…In a proofof-concept study, Gentiana lutea extract (containing amarogentin) significantly increased the lipid content of the treated skin areas. Enhancing lipid synthesis in human keratinocytes is essential for building an intact epidermal barrier, and therefore this therapeutic approach might be used to improve skin disorders like AD that are characterized by an impaired epidermal barrier (90).…”

Influence of phytogenics on recovery of the barrier function of intestinal porcine epithelial cells after a calcium switch

“…In a recent study, Gentiana lutea enhanced lipid synthesis in human keratinocytes, which are essential for building an intact epidermal barrier. It induced the expression of epidermal ceramide synthase 3, which also involves a MAPK signalling pathway (Wölfle et al, ). However, whilst Gentiana lutea can be used as treatment in some gastric disorders and might also influence the construction of specific tissue, no effect on the intestinal barrier function recovery after stress could be shown in the present study.…”

New Herbal Biomedicines for the Topical Treatment of Dermatological Disorders

“…In a placebo-controlled, double-blind half-side comparison with 33 volunteers 5% gentian extract significantly increased the lipid content of the epidermal stratum corneum on the volar forearm. In this body region skin lipids are nearly exclusively produced by keratinocytes [21]. The application occurred twice a day for 4 weeks.…”