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

Regulation of keratinocyte proliferation and differentiation by secoiridoid oleacein in monoculture and fibroblast co-culture models

Aberrant differentiation of keratinocytes is closely associated with both pathological skin disorders and non-pathological skin conditions, making the maintenance of normal differentiation process essential for skin integrity and homeostasis. This study investigated the effect of olive-derived secoiridoid oleacein (OC) on keratinocyte proliferation and differentiation in vitro and further validated it in a co-culture model with fibroblasts mimicking a skin-like environment. OC was compared with oleuropein (OP) as a reference compound having similar chemical structure and reported effects on skin barrier formation and wound healing. Notably, OC significantly increased the proliferation makers KRT5 and KRT14 and demonstrated wound healing effect under low-calcium condition, reflecting characteristics of the basal layer. Under high-calcium condition, OC markedly upregulated differentiation markers KRT10, IVL, FLG, and TGM1, along with differentiation characteristics such as cytoplasmic extensions and cell adhesion. Transcriptomic analysis revealed that OP and OC shared a common upstream pathway, Integrin/E-cadherin-Rho-MAPK, at the cytoplasm, while they showed distinct regulatory mechanisms within the nucleus. OP induced differentiation by suppressing stemness genes through epigenetic regulation, whereas OC secured differentiation stability by suppressing proliferative gene ESR1 and activating the DNA damage response from DNA damage or mechanical stress occurring during differentiation. Our study is the first to elucidate the dual regulatory effects of OC on keratinocyte proliferation and differentiation stage-dependently as well as its underlying molecular mechanisms, suggesting that the divergent regulatory mechanisms may be due to their structural differences. These findings highlight OC as a skin protective agent for maintaining skin health and suggest its therapeutic potential for skin disorders related to abnormal differentiation.

International Union of Basic and Clinical Pharmacology. CXVII: Taste 2 receptors-Structures, functions, activators, and blockers

For most vertebrates, bitter perception plays a critical role in the detection of potentially harmful substances in food items. The detection of bitter compounds is facilitated by specialized receptors located in the taste buds of the oral cavity. This work focuses on these receptors, including their sensitivities, structure-function relationships, agonists, and antagonists. The existence of numerous bitter taste receptor variants in the human population and the fact that several of them profoundly affect individual perceptions of bitter tastes are discussed as well. Moreover, the identification of bitter taste receptors in numerous tissues outside the oral cavity and their multiple proposed roles in these tissues are described briefly. Although this work is mainly focused on human bitter taste receptors, it is imperative to compare human bitter taste with bitter taste of other animals to understand which forces might have shaped the evolution of bitter taste receptors and their functions and to distinguish apparently typical human features from rather general ones. For readers who are not very familiar with the gustatory system, short descriptions of taste anatomy, signal transduction, and oral bitter taste receptor expression are included in the beginning of this article. SIGNIFICANCE STATEMENT: Apart from their role as sensors for potentially harmful substances in the oral cavity, the numerous additional roles of bitter taste receptors in tissues outside the gustatory system have recently received much attention. For careful assessment of their functions inside and outside the taste system, a solid knowledge of the specific and general pharmacological features of these receptors and the growing toolbox available for studying them is imperative and provided in this work.

Extragustatory bitter taste receptors in head and neck health and disease

Taste receptors, first described for their gustatory functions within the oral cavity and oropharynx, are now known to be expressed in many organ systems. Even intraoral taste receptors regulate non-sensory pathways, and recent literature has connected bitter taste receptors to various states of health and disease. These extragustatory pathways involve previously unexplored, clinically relevant roles for taste signaling in areas including susceptibility to infection, antibiotic efficacy, and cancer outcomes. Among other physicians, otolaryngologists who manage head and neck diseases should be aware of this growing body of evidence and its relevance to their fields. In this review, we describe the role of extragustatory taste receptors in head and neck health and disease, highlighting recent advances, clinical implications, and directions for future investigation. Additionally, this review will discuss known TAS2R polymorphisms and the associated implications for clinical prognosis.

Spasmolytic Activity of Gentiana lutea L. Root Extracts on the Rat Ileum: Underlying Mechanisms of Action

The roots of Gentiana lutea L. are utilized in the preparation of various beverages and herbal remedies, serving as a traditional remedy for gastrointestinal ailments. The spasmolytic activity that could substantiate the traditional use of G. lutea root had not been investigated. The main objective goal of the study was to determine the validity of its use as a traditional remedy. The extraction of G. lutea root was performed using a 50% hydroethanolic solvent with three different extraction techniques: ultrasound-assisted extraction (UAE), heat-assisted extraction, and percolation. The spasmolytic activity was tested on isolated rat ileum. The mechanism of action was monitored using the models of spontaneous contractions and acetylcholine-, histamine-, CaCl2-, Bay K8644-, L-NAME-, ODQ-, apamin-, BaCl2-, charybdotoxin-, glibenclamide-, TRAM-34-, and quinine-modified contractions. UAE, having the best bioactivity, was further subjected to a liquid-liquid extraction fractionation. HPLC phytochemical analysis was performed for all tested extracts and fractions. Gentian root extracts were rich in secoiridoids, xanthones, and flavonoids. The UAE has shown better results on spontaneous contractions in comparison to its fractions, leading to the more detailed testing of its spasmolytic mechanism of activity. The extract's activity is primarily mediated through intermediate conductance Ca2+-activated K+ channels, ATP-sensitive K+ channels, voltage-sensitive K+ channels, and mechanisms that activate Ca2+ channels. Overall, the G. lutea root shows great potential in the treatment of spasmodic gastrointestinal ailments.

Bitter Phytochemicals as Novel Candidates for Skin Disease Treatment

Skin diseases represent a global healthcare challenge due to their rising incidence and substantial socio-economic burden. While biological, immunological, and targeted therapies have brought a revolution in improving quality of life and survival rates for certain dermatological conditions, there remains a stringent demand for new remedies. Nature has long served as an inspiration for drug development. Recent studies have identified bitter taste receptors (TAS2Rs) in both skin cell lines and human skin. Additionally, bitter natural compounds have shown promising benefits in addressing skin aging, wound healing, inflammatory skin conditions, and even skin cancer. Thus, TAS2Rs may represent a promising target in all these processes. In this review, we summarize evidence supporting the presence of TAS2Rs in the skin and emphasize their potential as drug targets for addressing skin aging, wound healing, inflammatory skin conditions, and skin carcinogenesis. To our knowledge, this is a pioneering work in connecting information on TAS2Rs expression in skin and skin cells with the impact of bitter phytochemicals on various beneficial effects related to skin disorders.

Amarogentin inhibits vascular smooth muscle cell proliferation and migration and attenuates neointimal hyperplasia via AMPK activation

OBJECTIVES

Recent studies validated the expression of extraoral bitter taste receptors and established the importance of regulatory functions that are associated with various cellular biological processes of these receptors. However, the importance of bitter taste receptors' activity in neointimal hyperplasia has not yet been recognized. The bitter taste receptors activator amarogentin (AMA) is known to regulate a variety of cellular signals, including AMP-activated protein kinase (AMPK), STAT3, Akt, ERK, and p53, which are associated with neointimal hyperplasia.

MATERIALS AND METHODS

The present study assessed the effects of AMA on neointimal hyperplasia and explored the potential underlying mechanisms.

RESULTS

No cytotoxic concentration of AMA significantly inhibited the proliferation and migration of VSMCs induced by serum (15 % FBS) and PDGF-BB. In addition, AMA significantly inhibited neointimal hyperplasia of the cultured great saphenous vein in vitro and ligated mouse left carotid arteries in vivo, while the inhibitory effect of AMA on the proliferation and migration of VSMCs was mediated via the activation of AMPK-dependent signaling, which could be blocked via AMPK inhibition.

CONCLUSION

The present study revealed that AMA inhibited the proliferation and migration of VSMCs and attenuated neointimal hyperplasia, both in ligated mice carotid artery and cultured saphenous vein, which was mediated via a mechanism that involved AMPK activation. Importantly, the study highlighted the potential of AMA to be explored as a new drug candidate for neointimal hyperplasia.

The healing bitterness of Gentiana lutea L., phytochemistry and biological activities: A systematic review

Over many years, natural products have been a source of healing agents and have exhibited beneficial uses for treating human diseases. The Gentiana genus is the biggest genus in the Gentianaceae, with over 400 species distributed mainly in alpine zones of temperate countries around the world. Plants in the Gentiana genus have historically been used to treat a wide range of diseases. Still, only in the last years has particular attention been paid to the biological activities of Gentiana lutea Linn., also known as yellow Gentian or bitterwort. Several in vitro/vivo investigations and human interventional trials have demonstrated the promising activity of G. lutea extracts against oxidative stress, microbial infections, inflammation, obesity, atherosclerosis, etc.. A systematic approach was performed using Pubmed and Scopus databases to update G. lutea chemistry and activity. Specifically, this systematic review synthesized the major specialized bitter metabolites and the biological activity data obtained from different cell lines, animal models, and human interventional trials. This review aims to the exaltation of G. lutea as a source of bioactive compounds that can prevent and treat several human illnesses.

Safety of a feed additive consisting of a tincture derived from the roots of Gentiana lutea L. (gentian tincture) for all animal species (FEFANA asbl)

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety of a tincture derived from Gentiana lutea L. (gentian tincture). It is intended to be used as a sensory additive for all animal species. The product is a water/ethanol solution, with a dry matter content of approximately 4.3% and it contains on average 0.0836% polyphenols (of which 0.0463% are flavonoids and 0.0027% xanthones) and 0.0022% gentiopicroside. The additive is intended for use in complete feed or drinking water up to a maximum level of 50 mg tincture/kg for all animal species, except horses, for which the proposed use is 200 mg/kg in complete feed. In a previous assessment, due to the genotoxic potential identified in vitro for xanthones (gentisin and isogentisin) and gentiopicroside the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) could not conclude on the safety of the additive for long-living animals and on risks of genotoxicity and carcinogenicity for dermal exposure of unprotected users. The additive did not raise safety concern for short-living animals, consumers and the environment. The applicant has provided information in the form of literature to address the previously identified genotoxic activity of xanthones and gentiopicroside and the risk for the user. Considering that the literature identified provided no new evidence, the FEEDAP Panel reiterated that it is not in a position to conclude on the safety of the additive for long-living and reproductive animals. No conclusions could be drawn on the potential of the additive to be a dermal/eye irritant or a skin sensitiser. When handling the tincture, exposure of unprotected users to xanthones (gentisin and isogentisin) and gentiopicroside cannot be excluded. Therefore, to reduce the risk, the exposure of the users should be minimised.

Targeting TGF-β1/miR-21 pathway in keratinocytes reveals protective effects of silymarin on imiquimod-induced psoriasis mouse model

Epidermal cells integrate multiple signals that activate the signaling pathways involved in skin homeostasis. TGF-β1 signaling pathway upregulates microRNA (miR)-21-5p in keratinocytes and is often deregulated in skin diseases. To identify the bioactive compounds that enable to modulate the TGF-β1/miR-21-5p signaling pathway, we screened a library of medicinal plant extracts using our miR-ON RILES luciferase reporter system placed under the control of the miR-21-5p in keratinocytes treated with TGF-β1. We identified silymarin, a mixture of flavonolignans extracted from Silybum marianum (L.) Gaertn., as the most potent regulator of miR-21-5p expression. Using Argonaute 2 immunoprecipitation and RT-qPCR, we showed that silymarin regulates the expression of miR-21-5p through a noncanonical TGF-β1 signaling pathway, whereas RNA-sequencing analysis revealed three unexpected transcriptomic signatures associated with keratinocyte differentiation, cell cycle, and lipid metabolism. Mechanistically, we demonstrated that SM blocks cell cycle progression, inhibits keratinocyte differentiation through repression of Notch3 expression, stimulates lipid synthesis via activation of PPARγ signaling and inhibits inflammatory responses by suppressing the transcriptional activity of NF-κB. We finally showed that topical application of silymarin alleviates the development of imiquimod-induced psoriasiform lesions in mice by abrogating the altered expression levels of markers involved in inflammation, proliferation, differentiation, and lipid metabolism.

Ultrasound-Assisted Water Extraction of Gentiopicroside, Isogentisin, and Polyphenols from Willow Gentian “Dust” Supported by Hydroxypropyl-β-Cyclodextrin as Cage Molecules

The residue after sieving (“dust”) from the willow gentian underground parts is an unexploited herbal tea by-product, although it contains valuable bioactive compounds. Cyclodextrins as efficient green co-solvents, cage molecules, and multifunctional excipients could improve the extraction and contribute to the added value of the resulting extracts. The objective of this study was to determine the optimal conditions for the extraction of gentiopicroside, isogentisin, and total phenolics (TPC) from willow gentian “dust” using ultrasound-assisted water extraction coupled with hydroxypropyl-β-cyclodextrin (HPβCD). The influence of extraction temperature (X1: 20–80 °C), time (X2: 20–50 min), and HPβCD concentration (X3: 2–4% w/v) was analyzed employing the response surface methodology (RSM). The optimal extraction conditions for simultaneously maximizing the extraction yield of all monitored responses were X1: 74.89 °C, X2: 32.57 min, and X3: 3.01% w/v. The experimentally obtained response values under these conditions (46.96 mg/g DW for gentiopicroside, 0.51 mg/g DW for isogentisin, and 12.99 mg GAE/g DW for TPC) were in close agreement with those predicted, thus confirming the suitability and good predictive accuracy of the developed RSM models. Overall, the developed extraction system could be an applicable alternative strategy to improve the extraction of bioactive compounds from the underutilized “dust” of willow gentian underground parts.

Simultaneous Quantitative Analysis of the Major Bioactive Compounds in Gentianae Radix and its Beverages by UHPSFC-DAD

This study presents the first ultra-high performance supercritical fluid chromatography-diode array detector (UHPSFC-DAD) assay for simultaneous quantitation of secoiridoids, iridoids, xanthones, and xanthone glycosides in Gentiana lutea L. Separation was reached within 12 min on an Acquity UPC2 BEH 2-EP column using CO2 and methanol with 5.5% water as mobile phases. Method validation for nine selected marker compounds (gentisin, isogentisin, swertiamarin, sweroside, gentiopicroside, loganic acid, amarogentin, gentioside, and its isomer) confirmed the assay's sensitivity, linearity, precision, and accuracy. The practical applicability was proven by the analysis of 13 root specimens and 10 commercial liquid preparations (seven liqueurs and three clear spirits). In all root batches, the secoiridoid gentiopicroside dominated (2.1-5.6%) clearly over all other metabolites. In the liqueurs, the metabolite content and distribution were extremely variable: while gentiopicroside was the main compound in four liqueurs, sweroside dominated in one preparation and loganic acid in two others. In contrast, measurable amounts of the metabolites were not detected in any of the examined clear spirits.

The Anti-Inflammatory Effect of Humulus lupulus Extract In Vivo Depends on the Galenic System of the Topical Formulation

We demonstrated the anti-inflammatory and anti-oxidative effects of Humulus lupulus (HL) extract on solar simulator-irradiated primary human keratinocytes (PHKs) by analyzing ERK and p38 MAPK phosphorylation and production of IL-6 and IL-8. The anti-inflammatory effect of topically applied HL was further tested in vivo on human skin. To this end, we developed an oil-in-water (O/W) and a water-in-oil (W/O) cream with a lipid content of 40%. The anti-inflammatory effect of 1% HL extract incorporated in these two vehicles was assessed in a randomized, prospective, placebo controlled, double-blind UVB erythema study with 40 healthy volunteers. Hydrocortisone acetate (HCA) in the corresponding vehicle served as positive control. Surprisingly, both HL and HCA were only effective in the O/W system but not in the W/O formulation. Release studies using vertical diffusion cells (Franz cells) revealed that HCA was released in much higher amounts from the O/W cream compared to the W/O formulation. In summary, we have shown that 1% HL extract exerts anti-inflammatory effects comparable to 1% HCA, but only when incorporated in our O/W cream. Our findings confirm the critical role of the vehicle in topical anti-inflammatory systems.

Pharmacological significance of extra-oral taste receptors

It has recently been shown that taste receptors, in addition to being present in the oral cavity, exist in various extra-oral organs and tissues such as the thyroid, lungs, skin, stomach, intestines, and pancreas. Although their physiological function is not yet fully understood, it appears that they can help regulate the body's homeostasis and provide an additional defense function against pathogens. Since the vast majority of drugs are bitter, the greatest pharmacological interest is in the bitter taste receptors. In this review, we describe how bitter taste 2 receptors (TAS2Rs) induce bronchodilation and mucociliary clearance in the airways, muscle relaxation in various tissues, inhibition of thyroid stimulating hormone (TSH) in thyrocytes, and release of glucagon-like peptide-1 (GLP-1) and ghrelin in the digestive system. In fact, substances such as dextromethorphan, chloroquine, methimazole and probably glimepiride, being agonists of TAS2Rs, lead to these effects. TAS2Rs and taste 1 receptors (TAS1R2/3) are G protein-coupled receptors (GPCR). TAS1R2/3 are responsible for sweet taste perception and may induce GLP-1 release and insulin secretion. Umami taste receptors, belonging to the same superfamily of receptors, perform a similar function with regard to insulin. The sour and salty taste receptors work in a similar way, both being channel receptors sensitive to amiloride. Finally, gene-protein coupled receptor 40 (GPR40) and GPR120 for fatty taste perception are also protein-coupled receptors and may induce GLP-1 secretion and insulin release, similar to those of other receptors belonging to the same superfamily.

An update on extra-oral bitter taste receptors

Bitter taste-sensing type 2 receptors (TAS2Rs or T2Rs), belonging to the subgroup of family A G-protein coupled receptors (GPCRs), are of crucial importance in the perception of bitterness. Although in the first instance, TAS2Rs were considered to be exclusively distributed in the apical microvilli of taste bud cells, numerous studies have detected these sensory receptor proteins in several extra-oral tissues, such as in pancreatic or ovarian tissues, as well as in their corresponding malignancies. Critical points of extra-oral TAS2Rs biology, such as their structure, roles, signaling transduction pathways, extensive mutational polymorphism, and molecular evolution, have been currently broadly studied. The TAS2R cascade, for instance, has been recently considered to be a pivotal modulator of a number of (patho)physiological processes, including adipogenesis or carcinogenesis. The latest advances in taste receptor biology further raise the possibility of utilizing TAS2Rs as a therapeutic target or as an informative index to predict treatment responses in various disorders. Thus, the focus of this review is to provide an update on the expression and molecular basis of TAS2Rs functions in distinct extra-oral tissues in health and disease. We shall also discuss the therapeutic potential of novel TAS2Rs targets, which are appealing due to their ligand selectivity, expression pattern, or pharmacological profiles.

Anti-tyrosinase activity of South African Aloe species and isolated compounds plicataloside and aloesin

Tyrosinase is the key enzyme in the production of melanin. Tyrosinase inhibitors have gained interest in the cosmetics industry to prevent hyperpigmentation and skin-related disorders by inhibiting melanin production. It has been reported that several Aloe species exhibit anti-tyrosinase efficacy in vitro. In this study, the exudates of thirty-nine South African Aloe species were screened to identify species and compounds with anti-tyrosinase activity. Qualitative screening revealed that twenty-nine Aloe species exhibited tyrosinase inhibition activity with one to three active bands. Quantitative screening was performed for 29 species and expressed as IC50 values. Three species were further analysed and subsequently, aloesin and aloeresin A was isolated from A. ferox and plicataloside from A. plicatilis and A. chabaudii. Aloeresin A was determined to be a substrate of mushroom tyrosinase. Dose-response assays showed that aloesin (IC50 = 31.5 μM) and plicataloside (IC50 = 84.1 μM) exhibited moderate to weak activity. Molecular docking scores for plicataloside were considerably lower than for aloesin (P < 0.01), confirming its lower IC50. Several Aloe species may have potential for the management of hyperpigmentation or as a skin lightening agent. This is the first report showing that plicataloside, present in A. plicatilis and A. chabaudii, exhibits anti-tyrosinase activity.

Genus Gentiana: A review on phytochemistry, pharmacology and molecular mechanism

ETHNOPHARMACOLOGICAL RELEVANCE

As the largest genus of Gentianaceae family, the Gentiana genus harbors over 400 species, widely distributed in the alpine areas of temperate regions worldwide. Plants from Gentiana genus are traditionally used to treat a wide variety of diseases including easing pain dispelling rheumatism, and treating liver jaundice, chronic pharyngitis and arthritis in China since ancient times. In this review, a systematic and constructive overview of the traditional uses, phytochemistry, molecular mechanisms, toxicology and pharmacological activities of the researched species of genus Gentiana is provided.

MATERIALS AND METHODS

The used information in this review is based on various databases (PubMed, Science Direct, Wiley online library, Wanfang Data, Web of Science) through a search using the keyword "Gentiana" in the period of 1981-2019. Besides, other ethnopharmacological information was acquired from Chinese herbal classic books and Chinese pharmacopoeia 2015 edition.

RESULTS

The plants from Gentiana genus have a long tradition of various medicinal uses in Europe and Asia. Phytochemical studies showed that the main bioactive components isolated from this genus includes iridoids xanthones and flavonoids. These compounds and extracts isolated from this genus show a wide range of protective activities including hepatic protection, gastrointestinal protection, cardiovascular protection, immunomodulation, joint protection, pulmonary protection, bone protection and reproductive protection. Molecular mechanism studies also indicated several potential therapeutic targets in the treatment of certain diseases by plants from this genus. Besides, natural products from this plant show no significant animal toxicity, cytotoxicity or genotoxicity.

CONCLUSION

This review summarized the traditional medicinal uses, phytochemistry, pharmacology, toxicology and molecular mechanism of genus Gentiana, providing references and research tendency for plant-based drug development and further clinical studies.

Antiobesity Effects of Gentiana lutea Extract on 3T3-L1 Preadipocytes and a High-Fat Diet-Induced Mouse Model

Obesity is one of the most common metabolic diseases resulting in metabolic syndrome. In this study, we investigated the antiobesity effect of Gentiana lutea L. (GL) extract on 3T3-L1 preadipocytes and a high-fat-diet (HFD)-induced mouse model. For the induction of preadipocytes into adipocytes, 3T3-L1 cells were induced by treatment with 0.5 mM 3-isobutyl-1-methylxanthine, 1 mM dexamethasone, and 1 μg/mL insulin. Adipogenesis was assessed based on the messenger ribonucleic acid expression of adipogenic-inducing genes (adiponectin (Adipoq), CCAAT/enhancer-binding protein alpha (Cebpa), and glucose transporter type 4 (Slc2a4)) and lipid accumulation in the differentiated adipocytes was visualized by Oil Red O staining. In vivo, obese mice were induced with HFD and coadministered with 100 or 200 mg/kg/day of GL extract for 12 weeks. GL extract treatment inhibited adipocyte differentiation by downregulating the expression of adipogenic-related genes in 3T3-L1 cells. In the obese mouse model, GL extract prevented HFD-induced weight gain, fatty hepatocyte deposition, and adipocyte size by decreasing the secretion of leptin and insulin. In conclusion, GL extract shows antiobesity effects in vitro and in vivo, suggesting that this extract can be beneficial in the prevention of obesity.

Gentiana lutea Extract Modulates Ceramide Synthesis in Primary and Psoriasis-Like Keratinocytes

Gentiana lutea is a bitter herb that is traditionally used to improve gastric disorders. Recently, we have shown that Gentiana lutea extract (GE) also modulates the lipid metabolism of human keratinocytes in vitro and in vivo. In the present study, we investigated the role of GE on ceramide synthesis in human primary keratinocytes (HPKs) and psoriasis-like keratinocytes. We could demonstrate that GE increased the concentrations of glucosylceramides and the ceramide AS/AdS subclass without affecting the overall ceramide content in HPKs. The expression of ceramide synthase 3 (CERS3) and elongases (ELOVL1 and 4) was reduced in psoriasis lesions compared to healthy skin. Psoriasis-like HPKs, generated by stimulating HPKs with cytokines that are involved in the pathogenesis of psoriasis (IL-17, TNF-α, IL-22 and IFN-γ) showed increased levels of IL-6, IL-8 and increased expression of DEFB4A, as well as decreased expression of ELOVL4. The treatment with GE partly rescued the reduced expression of ELOVL4 in psoriasis-like HPKs and augmented CERS3 expression. This study has shown that GE modulates ceramide synthesis in keratinocytes. Therefore, GE might be a novel topical treatment for skin diseases with an altered lipid composition such as psoriasis.

New Herbal Biomedicines for the Topical Treatment of Dermatological Disorders

Herbal extracts and isolated plant compounds play an increasing role in the treatment of skin disorders and wounds. Several new herbal drugs, medicinal products and cosmetic products for the treatment of various skin conditions have been developed in recent years. In this nonsystematic review, we focus on herbal drugs that were tested in controlled clinical studies or in scientifically sound preclinical studies. The herbal biomedicines are intended to treat atopic dermatitis (St. John's wort, licorice, tormentil, bitter substances, evening primrose), psoriasis (araroba tree, lace flower, barberry bark, indigo, turmeric, olibanum, St. John's wort), actinic keratosis (birch bark, petty spurge), herpes simplex (lemon balm, sage and rhubarb), rosacea (green tea, licorice, tormentil) and acne vulgaris (tea tree oil, green tea, hop), or to improve photo protection (green tea, Dyer's weed, cocoa tree, carotinoids, licorice), aesthetic dermatology (licorice, pine bark, gotu kola) and wound healing (birch bark, onion).

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

A rapidly developing paradigm for modern health care is a proactive and individualized response to patients' symptoms, combining precision diagnosis and personalized treatment. Precision medicine is becoming an overarching medical discipline that will require a better understanding of biomarkers, phenotypes, endotypes, genotypes, regiotypes, and theratypes of diseases. The 100-year-old personalized allergen-specific management of allergic diseases has particularly contributed to early awareness in precision medicine. Polyomics, big data, and systems biology have demonstrated a profound complexity and dynamic variability in allergic disease between individuals, as well as between regions. Escalating health care costs together with questionable efficacy of the current management of allergic diseases facilitated the emergence of the endotype-driven approach. We describe here a precision medicine approach that stratifies patients based on disease mechanisms to optimize management of allergic diseases.

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

Background

The gut barrier is essential for animal health as it prevents the passage of potentially harmful foreign substances. The epithelial tight junctions support the intestinal barrier and can be disrupted by stress caused, for example, by pathogens or dietary or environmental factors, predisposing the host to disease. In animal husbandry, phytogenics (plant‐derived feed additives) are used to support and maintain growth, feed efficiency and health. Therefore, several phytogenics were tested in vitro for their influence on the barrier function recovery of intestinal porcine epithelial cells (IPEC‐J2) after disruption, particularly on the abundance of tight junction proteins.

Results

IPEC‐J2 treated with 1,000 µg/ml liquorice root extract, 80 µg/ml plant powder mix, or 80 µg/ml angelica root powder showed significantly higher trans‐epithelial electric resistance (TEER) 24 hr after tight junction disruption via a calcium switch assay than the control. In contrast, cells treated with 1,000 µg/ml oak bark extract showed a significantly lower TEER after 6 hr but not at later time points. The increased TEER caused by the liquorice root extract correlated with an increase in the abundance of the tight junction protein claudin‐4.

Conclusions

This study suggests potential beneficial effects of liquorice and angelica root extracts on the gut barrier function when used as feed additives for livestock. Further studies, especially in vivo, are necessary to confirm these findings.

Antiadipogenic Effects of Loganic Acid in 3T3-L1 Preadipocytes and Ovariectomized Mice

Obesity is caused by an excess storage of body fat, resulting from a chronic imbalance between energy intake and expenditure. Gentiana lutea L. (GL) root has been reported to reduce lipid accumulation in the aortic wall of diabetic rats. Here, we performed fractionation and isolation of the bioactive constituent(s) that may be responsible for the antiadipogenic effects of the GL root extract. A single compound, loganic acid, was identified as a candidate component in the 30% ethanol extract of GL. Loganic acid treatment significantly decreased the adipocyte differentiation of 3T3-L1 preadipocytes in a dose-dependent manner. The expression of key adipogenesis-related genes such as adiponectin (Adipoq), peroxisome proliferator-activated receptor gamma (Pparg), lipoprotein lipase (Lpl), perilipin1 (Plin1), fatty acid binding protein 4 (Fabp4), glucose transporter type 4 (Slc2a4), CCAAT/enhancer-binding protein alpha (Cebpa), and tumor necrosis factor-alpha (Tnf) were significantly reduced following treatment with loganic acid. In vivo experiments in an ovariectomy-induced obesity mouse model showed that loganic acid (oral administration with 10 and 50 mg/kg/day) significantly inhibited body weight gain, total fat increase, fatty hepatocyte deposition in the liver, and adipocyte enlargement in the abdominal visceral fat tissues. These results suggest that loganic acid in the GL root extract has antiadipogenic effects in vitro and in vivo. Loganic acid may be beneficial for the prevention and treatment of obesity, particularly in menopausal obese women.