Unveiling the Ability of Witch Hazel (Hamamelis virginiana L.) Bark Extract to Impair Keratinocyte Inflammatory Cascade Typical of Atopic Eczema.

Hamamelis virginiana L. bark extract is a traditional remedy for skin affections, including atopic dermatitis/eczema (AD). Hamamelis preparations contain tannins, including hamamelitannin (HT), although their pharmacological role in AD is still unknown. This study aimed to study the rational for its topical use by considering the impact of crucial biomarkers on AD pathogenesis. A standardized extract (HVE) (0.5−125 µg/mL) was compared to hamamelitannin (HT), its main compound (0.5−5 µg/mL), in a model of human keratinocytes (HaCaTs), challenged with an AD-like cytokine milieu (TNF-α, IFN-γ, and IL-4). HVE inhibited the release of mediators involved in skin autoimmunity (IL-6 and IL-17C) and allergy (TSLP, IL-6, CCL26, and MMP-9) with a concentration-dependent fashion (IC50s < 25 µg/mL). The biological mechanism was ascribed, at least in part, to the impairment of the NF-κB-driven transcription. Moreover, HVE counteracted the proliferative effects of IL-4 and recovered K10, a marker of skin differentiation. Notably, HT showed activity on well-known targets of IL-4 pathway (CCL26, K10, cell proliferation). To the best of our knowledge, this work represents the first demonstration of the potential role of Hamamelis virginiana in the control of AD symptoms, such as itch and skin barrier impairment, supporting the relevance of the whole phytocomplex.

The Nutraceutical Properties of Sumac (Rhus coriaria L.) against Gastritis: Antibacterial and Anti-Inflammatory Activities in Gastric Epithelial Cells Infected with H. pylori.

Sumac (Rhus coriaria L.) is a spice and medicinal herb traditionally used in the Mediterranean region and the Middle East. Since we previously demonstrated Sumac biological activity in a model of tumor necrosis factor alpha (TNF-α)-induced skin inflammation, the present work is aimed at further demonstrating a potential role in inflammatory disorders, focusing on gastritis. For this purpose, different polar extracts (water-W, ethanol-water-EW, ethanol-E, ethanol macerated-Em, acetone-Ac, ethylacetate-EtA) were investigated in gastric epithelial cells (GES-1) challenged by TNF-α or H. pylori infection. The ethanolic extracts (E, EW, Em) showed the major phenolic contents, correlating with lower half maximal inhibitory concentrations (IC50s) on the release of interleukin-8 (IL-8, <15 µg/mL) and interleukin-6 (IL-6, <20 µg/mL) induced by TNF-α. Similarly, they inhibited IL-8 release (IC50s < 70 µg/mL) during Helicobacter pylori (H. pylori) infection and exhibited a direct antibacterial activity at comparable concentrations (minimum inhibitory concentration (MIC) = 100 µg/mL). The phenolic content and the bioactivity of EW were maintained after simulated gastric digestion and were associated with nuclear factor kappa B (NF-κB) impairment, considered the main putative anti-inflammatory mechanism. On the contrary, an anti-urease activity was excluded. To the best of our knowledge, this is the first demonstration of the potential role of Sumac as a nutraceutical useful in H. pylori-related gastritis.

Cannabis sativa and Skin Health: Dissecting the Role of Phytocannabinoids.

The use of Cannabis sativa is currently recognized to ease certain types of chronic pain, reduce chemotherapy-induced nausea, and improve anxiety. Nevertheless, few studies highlighted the therapeutic potential of C. sativa extracts and related phytocannabinoids for a variety of widespread skin disorders including acne, atopic dermatitis, psoriasis, pruritus, and pain. This review summarized the current evidence on the effects of phytocannabinoids at the cutaneous level through the collection of in vitro, in vivo, and clinical studies published on PubMed, Scopus, Embase, and Web of Science until October 2020. Phytocannabinoids have demonstrated potential anti-inflammatory, antioxidant, anti-aging, and anti-acne properties by various mechanisms involving either CB1/2-dependent and independent pathways. Not only classical immune cells, but also several skin-specific actors, such as keratinocytes, fibroblasts, melanocytes, and sebocytes, may represent a target for phytocannabinoids. Cannabidiol, the most investigated compound, revealed photoprotective, antioxidant, and anti-inflammatory mechanisms at the cutaneous level, while the possible impact on cell differentiation, especially in the case of psoriasis, would require further investigation. Animal models and pilot clinical studies supported the application of cannabidiol in inflammatory-based skin diseases. Also, one of the most promising applications of non-psychotropic phytocannabinoids is the treatment of seborrheic disorders, especially acne. In conclusion, the incomplete knowledge of the role of the endocannabinoid system in skin disorders emerged as an important limit for pharmacological investigations. Moreover, the limited studies conducted on C. sativa extracts suggested a higher potency than single phytocannabinoids, thus stimulating new research on phytocannabinoid interaction.

Ribes nigrum Leaf Extract Preferentially Inhibits IFN-γ-Mediated Inflammation in HaCaT Keratinocytes.

Ribes nigrum L. (blackcurrant) leaf extracts, due to high levels of flavonols and anthocyanins, have been shown to exhibit beneficial effects in inflammatory diseases. However, whereas their traditional use has been investigated and validated in several models of inflammation and oxidative stress, the possible impact on skin disorders is still largely unknown. The purpose of this work was to elucidate the effects of R. nigrum leaf extract (RNLE) on keratinocyte-derived inflammatory mediators, elicited by a Th1 or Th2 cytokine milieu. HaCaT cells were challenged with TNF-α, either alone or in combination with the costimulatory cytokines IFN-γ or IL-4, and the release of proinflammatory cytokines and mediators (IL-8, IL-6, s-ICAM-1, and TSLP) was evaluated. The results showed that RNLE preferentially interferes with IFN-γ signaling, demonstrating only negligible activity on TNF-α or IL-4. This effect was attributed to flavonols, which might also account for the ability of RNLE to impair TNF-α/IL-4-induced TSLP release in a cAMP-independent manner. These results suggest that RNLE could have an antiallergic effect mediated in keratinocytes via mechanisms beyond histamine involvement. In conclusion, the discovery of RNLE preferential activity against IFN-γ-mediated inflammation suggests potential selectivity against Th1 type response and the possible use in Th1 inflammatory diseases.

Dietary Cameroonian Plants Exhibit Anti-Inflammatory Activity in Human Gastric Epithelial Cells.

In Cameroon, local plants are traditionally used as remedies for a variety of ailments. In this regard, several papers report health benefits of Cameroonian spices, which include antioxidant and anti-microbial properties, whereas gastric anti-inflammatory activities have never been previously considered. The present study investigates the antioxidant and anti-inflammatory activities of hydro-alcoholic extracts of eleven Cameroonian spices in gastric epithelial cells (AGS and GES-1 cells). The extracts showed antioxidant properties in a cell-free system and reduced H2O2-induced ROS generation in gastric epithelial cells. After preliminary screening on TNFα-induced NF-κB driven transcription, six extracts from Xylopia parviflora, Xylopia aethiopica, Tetrapleura tetraptera, Dichrostachys glomerata, Aframomum melegueta, and Aframomum citratum were selected for further studies focusing on the anti-inflammatory activity. The extracts reduced the expression of some NF-κB-dependent pro-inflammatory mediators strictly involved in the gastric inflammatory process, such as IL-8, IL-6, and enzymes such as PTGS2 (COX-2), without affecting PTGS1 (COX-1). In conclusion, the selected extracts decreased pro-inflammatory markers by inhibiting the NF-κB signaling in gastric cells, justifying, in part, the traditional use of these spices. Other molecular mechanisms cannot be excluded, and further studies are needed to better clarify their biological activities at the gastric level.

Cannabis sativa L. extract and cannabidiol inhibit in vitro mediators of skin inflammation and wound injury.

Skin inflammatory diseases result from complex events that include dysregulation and abnormal expression of inflammatory mediators or their receptors in skin cells. The present study investigates the potential effect of a Cannabis sativa L. ethanolic extract standardized in cannabidiol as antiinflammatory agent in the skin, unraveling the molecular mechanisms in human keratinocytes and fibroblasts. The extract inhibited the release of mediators of inflammation involved in wound healing and inflammatory processes occurring in the skin. The mode of action involved the impairment of the nuclear factor-kappa B (NF-κB) pathway since the extract counteracted the tumor necrosis factor-alpha-induced NF-κB-driven transcription in both skin cell lines. Cannabis extract and cannabidiol showed different effects on the release of interleukin-8 and vascular endothelial growth factor, which are both mediators whose genes are dependent on NF-κB. The effect of cannabidiol on the NF-κB pathway and metalloproteinase-9 (MMP-9) release paralleled the effect of the extract thus making cannabidiol the major contributor to the effect observed. Down-regulation of genes involved in wound healing and skin inflammation was at least in part due to the presence of cannabidiol. Our findings provide new insights into the potential effect of Cannabis extracts against inflammation-based skin diseases.