Minor Cannabinoids as Inhibitors of Skin Inflammation: Chemical Synthesis and Biological Evaluation.

Despite millennia of therapeutic plant use, deliberate exploitation of Cannabis's diverse biomedical potential has only recently gained attention. Bioactivity studies focus mainly on cannabidiol (CBD) and tetrahydrocannabinol (THC) with limited information about the broader cannabinome's "minor phytocannabinoids". In this context, our research targeted the synthesis of minor cannabinoids containing a lateral chain with 3 or 4 carbon atoms, focusing on cannabigerol (CBG) and cannabichromene (CBC) analogues. Using known and innovative strategies, we achieved the synthesis of 11 C3 and C4 analogues, five of which were inhibitors of skin inflammation, with the CBG-C4 ester derivative emerging as the most potent compound.

Investigation into the Anti-Acne Effects of Castanea sativa Mill Leaf and Its Pure Ellagitannin Castalagin in HaCaT Cells Infected with Cutibacterium acnes.

Acne vulgaris is a prevalent skin disorder affecting many young individuals, marked by keratinization, inflammation, seborrhea, and colonization by Cutibacterium acnes (C. acnes). Ellagitannins, known for their antibacterial and anti-inflammatory properties, have not been widely studied for their anti-acne effects. Chestnut (Castanea sativa Mill., C. sativa), a rich ellagitannin source, including castalagin whose acne-related bioactivity was previously unexplored, was investigated in this study. The research assessed the effect of C. sativa leaf extract and castalagin on human keratinocytes (HaCaT) infected with C. acnes, finding that both inhibited IL-8 and IL-6 release at concentrations below 25 µg/mL. The action mechanism was linked to NF-κB inhibition, without AP-1 involvement. Furthermore, the extract displayed anti-biofilm properties and reduced CK-10 expression, indicating a potential role in mitigating inflammation, bacterial colonization, and keratosis. Castalagin's bioactivity mirrored the extract's effects, notably in IL-8 inhibition, NF-κB inhibition, and biofilm formation at low µM levels. Other polyphenols, such as flavonol glycosides identified via LC-MS, might also contribute to the extract's biological activities. This study is the first to explore ellagitannins' potential in treating acne, offering insights for developing chestnut-based anti-acne treatments pending future in vivo studies.

Investigating the Molecular Mechanisms Underlying Early Response to Inflammation and Helicobacter pylori Infection in Human Gastric Epithelial Cells.

Helicobacter pylori is a leading cause of chronic gastric inflammation, generally associated with gastritis and adenocarcinoma. Activation of the NF-κB pathway mainly contributes to the inflammatory phenotype observed in H. pylori infection in humans and experimental models. Since the gastric epithelium undergoes rapid turnover, inflammation and pathogenicity of H. pylori result from early phase and chronically activated pathways. In the present study we investigated the early host response to H. pylori in non-tumoral human gastric epithelial cells (GES-1). To dissect the pathogen-specific mechanisms we also examined the response to tumor necrosis factor (TNF), a prototypical cytokine. By analyzing the activation state of NF-κB signaling, cytokine expression and secretion, and the transcriptome, we found that the inflammatory response of GES-1 cells to H. pylori and TNF results from activation of multiple pathways and transcription factors, e.g., NF-κB and CCAAT/enhancer-binding proteins (CEBPs). By comparing the transcriptomic profiles, we found that H. pylori infection induces a less potent inflammatory response than TNF but affects gene transcription to a greater extent by specifically inducing transcription factors such as CEBPß and numerous zinc finger proteins. Our study provides insights on the cellular pathways modulated by H. pylori in non-tumoral human gastric cells unveiling new potential targets.

The antiviral and immunomodulatory activities of propolis: An update and future perspectives for respiratory diseases.

Propolis is a complex natural product that possesses antioxidant, anti-inflammatory, immunomodulatory, antibacterial, and antiviral properties mainly attributed to the high content in flavonoids, phenolic acids, and their derivatives. The chemical composition of propolis is multifarious, as it depends on the botanical sources from which honeybees collect resins and exudates. Nevertheless, despite this variability propolis may have a general pharmacological value, and this review systematically compiles, for the first time, the existing preclinical and clinical evidence of propolis activities as an antiviral and immunomodulatory agent, focusing on the possible application in respiratory diseases. In vitro and in vivo assays have demonstrated propolis broad-spectrum effects on viral infectivity and replication, as well as the modulatory actions on cytokine production and immune cell activation as part of both innate and adaptive immune responses. Clinical trials confirmed propolis undeniable potential as an effective therapeutic agent; however, the lack of rigorous randomized clinical trials in the context of respiratory diseases is tangible. Since propolis is available as a dietary supplement, possible use for the prevention of respiratory diseases and their deleterious inflammatory drawbacks on the respiratory tract in humans is considered and discussed. This review opens up new perspectives on the clinical investigation of neglected propolis biological properties which, now more than ever, are particularly relevant with respect to the recent outbreaks of pandemic respiratory infections.

Effect of an herbal formulation containing Peganum harmala L. and Fraxinus excelsior L. on oxidative stress, memory impairment and withdrawal syndrome induced by morphine.

Background: Traditional Persian medicine has introduced effective remedies in opioid dependence care. One of the most widely used remedies is an herbal formulation containing Peganum harmala L. and Fraxinus excelsior L. (HF). This study investigated the effects of HF to attenuate the withdrawal signs and rewarding effects in morphine-dependent rats.Methods: Forty-nine male Wistar rats were randomly divided into seven groups. The control and vehicle groups received normal saline and sodium carboxymethyl cellulose, respectively. The morphine group received morphine for one week. The single and daily dose of HF groups received morphine similar to the morphine group, and HF (1.4 and 2.8 g/kg) once a day in the daily dose group and only on the last day of the experiment in the single dose of HF group. Finally, the withdrawal signs as well biochemical tests were evaluated. The behavioral parameters were assessed by conditioned place preference (CPP), elevated plus-maze and Y-maze tests. The antioxidant activity of HF was evaluated by measurement of serum contents of malondialdehyde, stable nitric oxide metabolites and total antioxidant capacity (TAC). Moreover, the protein expression of c-fos was assessed by western blotting.Results: Daily treatment with HF significantly reduced the score of CPP behavioral test, all of the withdrawal signs, TAC and the c-fos protein level.Conclusions: The results indicated that HF might be a promising complementary treatment in reducing morphine-induced physical and psychological dependence probably through modulation of c-fos protein expression.

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.

Hydrolyzable Tannins in the Management of Th1, Th2 and Th17 Inflammatory-Related Diseases.

Plants rich in hydrolyzable tannins were traditionally used all over the world for a variety of chronic inflammatory disorders, including arthritis, colitis, and dermatitis. However, the knowledge of their immunological targets is still limited though fundamental for their rational use in phytotherapy. The recent advances regarding the pathogenesis of inflammatory-based diseases represent an opportunity to elucidate the pharmacological mechanism of plant-derived metabolites with immunomodulatory activity. This review collects recent articles regarding the role of hydrolyzable tannins and their gut metabolites in Th1, Th2, and Th17 inflammatory responses. In line with the traditional use, rheumatoid arthritis (RA), inflammatory bowel diseases (IBDs), psoriasis, atopic dermatitis (AD), and asthma were the most investigated diseases. A substantial body of in vivo studies suggests that, beside innate response, hydrolyzable tannins may reduce the levels of Th-derived cytokines, including IFN-γ, IL-17, and IL-4, following oral administration. The mode of action is multitarget and may involve the impairment of inflammatory transcription factors (NF-κB, NFAT, STAT), enzymes (MAPKs, COX-2, iNOS), and ion channels. However, their potential impact on pathways with renewed interest for inflammation, such as JAK/STAT, or the modulation of the gut microbiota demands dedicate studies.

Development and Validation of a Reversed-Phase HPLC Method with UV Detection for the Determination of L-Dopa in Vicia faba L. Broad Beans.

L-Dopa (LD), a substance used medically in the treatment of Parkinson's disease, is found in several natural products, such as Vicia faba L., also known as broad beans. Due to its low chemical stability, LD analysis in plant matrices requires an appropriate optimization of the chosen analytical method to obtain reliable results. This work proposes an HPLC-UV method, validated according to EURACHEM guidelines as regards linearity, limits of detection and quantification, precision, accuracy, and matrix effect. The LD extraction was studied by evaluating its aqueous stability over 3 months. The best chromatographic conditions were found by systematically testing several C18 stationary phases and acidic mobile phases. In addition, the assessment of the best storage treatment of Vicia faba L. broad beans able to preserve a high LD content was performed. The best LD determination conditions include sun-drying storage, extraction in HCl 0.1 M, chromatographic separation with a Discovery C18 column, 250 × 4.6 mm, 5 µm particle size, and 99% formic acid 0.2% v/v and 1% methanol as the mobile phase. The optimized method proposed here overcomes the problems linked to LD stability and separation, thus contributing to the improvement of its analytical determination.

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.

Comparison of Two Ginkgo biloba L. Extracts on Oxidative Stress and Inflammation Markers in Human Endothelial Cells.

Atherosclerosis is characterized by interaction between immune and vascular endothelial cells which is mediated by adhesion molecules occurring on the surface of the vascular endothelium leading to massive release of proinflammatory mediators. Ginkgo biloba L. (Ginkgoaceae) standardized extracts showing beneficial effects are commonly prepared by solvent extraction, and acetone is used according to the European Pharmacopoeia recommendations; the well-known Ginkgo biloba acetone extract EGb761® is the most clinically investigated. However, in some countries, the allowed amount of solvent is limited to ethanol, thus implying that the usage of a standardized Ginkgo biloba ethanol extract may be preferred in all those cases, such as for food supplements. The present paper investigates if ethanol and acetone extracts, with comparable standardization, may be considered comparable in terms of biological activity, focusing on the radical scavenging and anti-inflammatory activities. Both the extracts showed high inhibition of TNFα-induced VCAM-1 release (41.1-43.9 µg/mL), which was partly due to the NF-κB pathway impairment. Besides ROS decrease, cAMP increase following treatment with ginkgo extracts was addressed and proposed as further molecular mechanism responsible for the inhibition of endothelial E-selectin. No statistical difference was observed between the extracts. The present study demonstrates for the first time that ethanol and acetone extracts show comparable biological activities in human endothelial cell, thus providing new insights into the usage of ethanol extracts in those countries where restrictions in amount of acetone are present.

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.

A bio-guided approach for the development of a chestnut-based proanthocyanidin-enriched nutraceutical with potential anti-gastritis properties.

Gastritis is a widely spread inflammatory disease, mostly caused by Helicobacter pylori infection. Release of IL-8 by the stomach epithelium is a hallmark of gastritis and contributes to the amplification of the inflammatory state. Pharmacological modulation of IL-8 release is a strategy to relieve gastric inflammation and prevent more severe clinical outcomes. In search of nutraceuticals with potential anti-gastritis properties we used a bio-guided approach based on IL-8 secretion by gastric cells to characterize extracts from the fruits of different chestnut varieties. We found that the ability to inhibit IL-8 secretion correlated with the amount of proanthocyanidins and was associated to the not edible parts of chestnut in all the tested varieties. We also found that the anti-inflammatory activity is preserved upon mild thermal treatment and after in vitro simulated gastric digestion. By combining a robust bio-guided approach with a comprehensive analysis of the tannin fraction of chestnut extracts, we provide evidence for the potential use of chestnut-based nutraceuticals in human gastritis. The bioactive components of chestnut fruits inhibit IL-8 secretion by impairing NF-κB signaling and by other mechanisms, thus opening new applications of proanthocyanidins for inflammation-based diseases.

HaCaT Cells as a Reliable In Vitro Differentiation Model to Dissect the Inflammatory/Repair Response of Human Keratinocytes.

Cultured primary human keratinocytes are frequently employed for studies of immunological and inflammatory responses; however, interpretation of experimental data may be complicated by donor to donor variability, the relatively short culture lifetime, and variations between passages. To standardize the in vitro studies on keratinocytes, we investigated the use of HaCaT cells, a long-lived, spontaneously immortalized human keratinocyte line which is able to differentiate in vitro, as a suitable model to follow the release of inflammatory and repair mediators in response to TNFα or IL-1ß. Different treatment conditions (presence or absence of serum) and differentiation stimuli (increase in cell density as a function of time in culture and elevation of extracellular calcium) were considered. ELISA and Multiplex measurement technologies were used to monitor the production of cytokines and chemokines. Taken together, the results highlight that Ca2+ concentration in the medium, cell density, and presence of serum influences at different levels the release of proinflammatory mediators by HaCaT cells. Moreover, HaCaT cells maintained in low Ca2+ medium and 80% confluent are similar to normal keratinocytes in terms of cytokine production suggesting that HaCaT cells may be a useful model to investigate anti-inflammatory interventions/therapies on skin diseases.

Botanicals as Modulators of Neuroplasticity: Focus on BDNF.

The involvement of brain-derived neurotrophic factor (BDNF) in different central nervous system (CNS) diseases suggests that this neurotrophin may represent an interesting and reliable therapeutic target. Accordingly, the search for new compounds, also from natural sources, able to modulate BDNF has been increasingly explored. The present review considers the literature on the effects of botanicals on BDNF. Botanicals considered were Bacopa monnieri (L.) Pennell, Coffea arabica L., Crocus sativus L., Eleutherococcus senticosus Maxim., Camellia sinensis (L.) Kuntze (green tea), Ginkgo biloba L., Hypericum perforatum L., Olea europaea L. (olive oil), Panax ginseng C.A. Meyer, Rhodiola rosea L., Salvia miltiorrhiza Bunge, Vitis vinifera L., Withania somnifera (L.) Dunal, and Perilla frutescens (L.) Britton. The effect of the active principles responsible for the efficacy of the extracts is reviewed and discussed as well. The high number of articles published (more than one hundred manuscripts for 14 botanicals) supports the growing interest in the use of natural products as BDNF modulators. The studies reported strengthen the hypothesis that botanicals may be considered useful modulators of BDNF in CNS diseases, without high side effects. Further clinical studies are mandatory to confirm botanicals as preventive agents or as useful adjuvant to the pharmacological treatment.

Strawberry tannins inhibit IL-8 secretion in a cell model of gastric inflammation.

In the present study we chemically profiled tannin-enriched extracts from strawberries and tested their biological properties in a cell model of gastric inflammation. The chemical and biological features of strawberry tannins after in vitro simulated gastric digestion were investigated as well. The anti-inflammatory activities of pure strawberry tannins were assayed to get mechanistic insights. Tannin-enriched extracts from strawberries inhibit IL-8 secretion in TNFα-treated human gastric epithelial cells by dampening the NF-κB signaling. In vitro simulated gastric digestion slightly affected the chemical composition and the biological properties of strawberry tannins. By using pure compounds, we found that casuarictin may act as a pure NF-κB inhibitor while agrimoniin inhibits IL-8 secretion also acting on other biological targets; in our system procyanidin B1 prevents the TNFα-induced effects without interfering with the NF-κB pathway. We conclude that strawberry tannins, even after in vitro simulated gastric digestion, exert anti-inflammatory activities at nutritionally relevant concentrations.

Evaluation of the Anti-Inflammatory Activity of Raisins (Vitis vinifera L.) in Human Gastric Epithelial Cells: A Comparative Study.

Raisins (Vitis vinifera L.) are dried grapes largely consumed as important source of nutrients and polyphenols. Several studies report health benefits of raisins, including anti-inflammatory and antioxidant properties, whereas the anti-inflammatory activity at gastric level of the hydro-alcoholic extracts, which are mostly used for food supplements preparation, was not reported until now. The aim of this study was to compare the anti-inflammatory activity of five raisin extracts focusing on Interleukin (IL)-8 and Nuclear Factor (NF)-κB pathway. Raisin extracts were characterized by High Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD) analysis and screened for their ability to inhibit Tumor necrosis factor (TNF)α-induced IL-8 release and promoter activity in human gastric epithelial cells. Turkish variety significantly inhibited TNFα-induced IL-8 release, and the effect was due to the impairment of the corresponding promoter activity. Macroscopic evaluation showed the presence of seeds, absent in the other varieties; thus, hydro-alcoholic extracts from fruits and seeds were individually tested on IL-8 and NF-κB pathway. Seed extract inhibited IL-8 and NF-κB pathway, showing higher potency with respect to the fruit. Although the main effect was due to the presence of seeds, the fruit showed significant activity as well. Our data suggest that consumption of selected varieties of raisins could confer a beneficial effect against gastric inflammatory diseases.

Catha edulis Leaves: Morphological Characterization and Anti-Inflammatory Properties in an In Vitro Model of Gastritis.

Khat leaves, indigenous to eastern Africa, have been chewed for centuries for their stimulant effects, attributed to alkaloids such as cathinone and cathine. Although associated with gastric disorders like gastritis and gastro-oesophageal reflux disease, the underlying molecular mechanisms remain unclear. This study aimed to examine the morpho-anatomy of khat leaves using light microscopy and histochemistry and to assess the effects of leaf extracts and alkaloids on human gastric epithelial cells (GES-1). The study identified specific cells in the palisade-spongy transition zone as storage sites for psychoactive alkaloids. Leaf extracts were prepared by mimicking the chewing process, including a prolonged salivary phase followed by a gastric phase. Cytotoxicity and cell viability were evaluated using LDH and MTT assays, respectively. Additionally, the impact on IL-8 secretion, a key chemokine in gastric inflammation, was analysed under normal and TNF-α-stimulated conditions. The results showed no increase in cytotoxicity up to 250 µg/mL. However, there was a significant decrease in cell metabolism and a reduction in both basal and TNF-α-induced IL-8 secretion, but cathinone and cathine were inactive. These findings suggest that khat may not directly cause the gastric issues reported in the literature, which would rather be attributed to other confounding factors, highlighting the need for further research to clarify its biological impacts.

From Primary Data to Ethnopharmacological Investigations on Achillea erba-rotta subsp. moschata (Wulfen) I.Richardson as a Remedy against Gastric Ailments in Valmalenco (Italy).

(1) Background: Within the framework of the European Interreg Italy-Switzerland B-ICE & Heritage project (2018-2022), this study originated from a three-year ethnobotanical survey in Valmalenco (Sondrio, Italy). Following a preliminary work published by our group, this research further explored the folk therapeutic use of Achillea erba-rotta subsp. moschata (Wulfen) I.Richardson (Asteraceae) for dyspepsia disorders, specifically its anti-inflammatory potential at a gastrointestinal level. (2) Methods: Semi-structured interviews were performed. The bitter taste was investigated through molecular docking software (PLANTS, GOLD), while the anti-inflammatory activity of the hydroethanolic extract, infusion, and decoction was evaluated based on the release of IL-8 and IL-6 after treatment with TNFα or Helicobacter pylori. The minimum inhibitory concentration and bacterial adhesion on the gastric epithelium were evaluated. (3) Results: In total, 401 respondents were interviewed. Molecular docking highlighted di-caffeoylquinic acids as the main compounds responsible for the interaction with bitter taste receptors. The moderate inhibition of IL-6 and IL-8 release was recorded, while, in the co-culture with H. pylori, stronger anti-inflammatory potential was expressed (29-45 µg/mL). The concentration-dependent inhibition of H. pylori growth was recorded (MIC = 100 µg/mL), with a significant anti-adhesive effect. (4) Conclusions: Confirming the folk tradition, the study emphasizes the species' potentiality for dyspepsia disorders. Future studies are needed to identify the components mostly responsible for the biological effects.

Plant food supplements with anti-inflammatory properties: a systematic review (I).

Plant food supplements (PFS) receive great acceptance by European consumers. However, quality and efficacy of these products remain a question of concern. The aim of this systematic review is to summarize and critically evaluate the evidence for or against the efficacy of PFS for coping inflammatory conditions by considering epidemiological and human intervention studies. The review, which consists of two parts, considers Olea europea L., Camellia sinensis L., Vitis vinifera L., and Matricaria recutita L., which are herbal material frequently used also as food. The search retrieved 1251 publications. By applying the inclusion/exclusion criteria, the final number of papers was 91. Vitis vinifera L. showed promising results, but other trials should be performed in order to assessing the efficacy. Surprisingly, it was impossible to draw conclusions for the anti-inflammatory effect of Camellia sinensis L. as green tea. No studies were found on the leaves of Olea europea L. whereas more human trials are needed to assess the anti-inflammatory effect of olive oil. Only one study for Matricaria recutita L. was selected. In conclusion, it is advisable to conduct further studies with more homogeneous population and larger number of subjects by avoiding the heterogeneity of the herbal preparations considered.