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

Tea for histamine anti-allergy: component analysis of tea extracts and potential mechanism for treating histamine anti-allergy

In China, Camellia plants are widely used to reduce atopic dermatitis and inflammation-related diseases, but their protective mechanisms remain unclear. This study investigated the anti-allergic dermatitis, anti-oxidation and anti-inflammation effect and underlying mechanism of five Camellia species, including Camellia ptilophylla Chang, Camellia assamica Chang var. Kucha Chang, Camellia parvisepala Chang, Camellia arborescens Chang, and C. assamica M. Chang. A total of about 110 chemical compositions were detected from five Camellia teas extracts. The level of mast cell infiltration in the model mice skin was determined by HE (Hematoxylin and eosin) staining and toluidine blue staining, and the level of interleukin-1β (IL-1β) and nerve growth factor was detected by immunohistochemistry. The five Camellia tea leaf extracts have histamine-induced allergic dermatitis. Lipopolysaccharide (Lipopolysaccharide)-induced murine macrophage RAW264.7 inflammation model was found to secrete NF-κB factor, as shown by immunofluorescence, and reactive oxygen species secretion and related cytokine levels were detected. The results suggested that Camellia's five tea extracts had the ability to resist cellular oxidative stress. In addition, the results of cell inflammatory cytokines including fibronectin (FN) and interleukin-6 (IL-6) suggested that the five tea extracts of Camellia had anti-inflammatory effects. Therefore, it is suggested that five Camellia teas may possess inhibitory properties against allergic reactions, oxidative stress, and inflammation, and may prove beneficial in the treatment of allergies.

Optimization and Validation of Procyanidins Extraction and Phytochemical Profiling of Seven Herbal Matrices of Nutraceutical Interest

Several medicinal herbal plants are extensively used as sources of bioactive compounds with beneficial effects on human health. This study assessed the procyanidin and polyphenol profiles together with the antioxidant potential of seven herbal medical matrices. To achieve this aim, procyanidin extraction from grape pomace was optimized and validated by monitoring monomeric-trimeric procyanidins. The proposed quantification method was applied to the seven medical herbs, and it proved to be a very efficient protocol for procyanidin-rich extracts analysis. In addition, the Paullinia cupana Kunth. seed was identified as a very rich source of procyanidins (about 5 mg/g dry matrix of each dimeric and about 3 mg/g dry matrix trimeric) with high antioxidant properties. The polyphenolic profile was assessed by HPLC-HESI-MS/MS analysis. The in vitro antioxidant activity was evaluated by DPPH assay to explore the antioxidant properties of the extracts, which were substantially higher in Peumus boldus Molina leaves extracts (935.23 ± 169 μmol of Trolox equivalent/g of dry weight) concerning the other matrices. Moreover, a high Pearson coefficient value was observed between the total flavonoid content (TFC) and DPPH in comparison with the total polyphenol content (TPC) and DPPH, indicating flavonoids as the principal bioactive with antioxidant activity in the extracts.

Heat shock protein 90 inhibition attenuates inflammation in models of atopic dermatitis: a novel mechanism of action

Background

Heat shock protein 90 (HSP90) is an important chaperone supporting the function of many proinflammatory client proteins. Recent studies indicate HSP90 inhibition may be a novel mechanism of action for inflammatory skin diseases; however, this has not been explored in atopic dermatitis (AD).

Objectives

Our study aimed to investigate HSP90 as a novel target to treat AD.

Methods

Experimental models of AD were used including primary human keratinocytes stimulated with cytokines (TNF/IFNγ or TNF/IL-4) and a mouse model established by MC903 applications.

Results

In primary human keratinocytes using RT-qPCR, the HSP90 inhibitor RGRN-305 strongly suppressed the gene expression of Th1- (TNF, IL1B, IL6) and Th2-associated (CCL17, CCL22, TSLP) cytokines and chemokines related to AD. We next demonstrated that topical and oral RGRN-305 robustly suppressed MC903-induced AD-like inflammation in mice by reducing clinical signs of dermatitis (oedema and erythema) and immune cell infiltration into the skin (T cells, neutrophils, mast cells). Interestingly, topical RGRN-305 exhibited similar or slightly inferior efficacy but less weight loss compared with topical dexamethasone. Furthermore, RNA sequencing of skin biopsies revealed that RGRN-305 attenuated MC903-induced transcriptome alterations, suppressing genes implicated in inflammation including AD-associated cytokines (Il1b, Il4, Il6, Il13), which was confirmed by RT-qPCR. Lastly, we discovered using Western blot that RGRN-305 disrupted JAK-STAT signaling by suppressing the activity of STAT3 and STAT6 in primary human keratinocytes, which was consistent with enrichment analyses from the mouse model.

Conclusion

HSP90 inhibition by RGRN-305 robustly suppressed inflammation in experimental models mimicking AD, proving that HSP90 inhibition may be a novel mechanism of action in treating AD.

In vitro and in vivo anti-eczema effect of Artemisia annua aqueous extract and its component profiling

ETHNOPHARMACOLOGICAL RELEVANCE

Artemisia annua L. belongs to the Asteraceae family and has a long history of clinical application in China. It has been widely used for centuries to treat fever, malaria, jaundice and some skin diseases (such as scabies and sores). Modern pharmacological studies have shown that it has anti-inflammatory, immunomodulatory, antimalarial and antibacterial effects.

AIM OF STUDY

This study aimed to investigate the anti-eczema effect of A. annua aqueous extract (AAE), profile its potential bioactive components and try to explore its possible underlying mechanisms.

MATERIALS AND METHODS

The MTT assay was employed to assess the cytotoxicity of AAE. The anti-eczema effect of AAE was evaluated using both an in vitro 3D epidermal inflammation model and an in vivo guinea pig itching model. The bioactive components of AAE were characterized by ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry coupled with the UNIFI platform.

RESULTS

In this study, we found that AAE is safe for primary human skin keratinocytes at concentrations ranging from 31.3 μg/mL to 250 μg/mL. Further investigations indicate that AAE can increase the itching threshold, inhibit the expression of the inflammatory cytokine TSLP, and promote the expression of FLG mRNA. Additionally, the utilization of UPLC-QTOF/MS and UNIFI platform enabled us to identify 61 potential bioactive components of AAE, with sesquiterpenes and phenolic acids being the most abundant components.

CONCLUSIONS

In this study, the anti-inflammatory and anti-itch effects of the A. annua extract were revealed, along with sesquiterpenes and phenolic acids were identified as potential bioactive components according to literature. The AAE extract holds potential for utilization in the treatment of eczema.

Ginnalin A and hamamelitannin: the unique gallotannins with promising anti-carcinogenic potential

Tannins are secondary metabolites that belong to the family of polyphenolic compounds and have gained a huge interest among researchers due to their versatile therapeutic potential. After lignin, these are the second most abundant polyphenols found in almost every plant part like stem, bark, fruit, seed, leaves, etc. Depending upon their structural composition, these polyphenols can be divided into two distinct groups, namely condensed tannins and hydrolysable tannins. Hydrolysable tannins can be further divided into two types: gallotannins and ellagitannins. Gallotannins are formed by the esterification of D-glucose hydroxyl groups with gallic acid. The gallolyl moieties are bound by a depside bond. The current review focuses mainly on the anti-carcinogenic potential of recently discovered gallotannins, ginnalin A, and hamamelitannin (HAM). Both of these gallotannins possess two galloyl moieties linked to a core monosaccharide having anti-oxidant, anti-inflammatory, and anti-carcinogenic abilities. Ginnalin A is found in plants of the genus Acer whereas HAM is present in witch hazel plants. The biosynthetic pathway of ginnalin A along with the mechanism of the anti-cancer therapeutic potential of ginnalin A and HAM has been discussed. This review will certainly help researchers to work further on the chemo-therapeutic abilities of these two unique gallotannins.

From Hamamelitannin Synthesis to the Study of Enzymatic Acylations of D-Hamamelose

The bioactive natural substance, hamamelitannin, was effectively synthesized in two ways. The chemical acylation of 2,3-O-isopropylidene-α,β-D-hamamelofuranose promoted by Bu2SnO using 3,4,5-tri-O-acetylgalloyl chloride, followed by the deprotection provided hamamelitannin in 79%. Pilot enzymatic benzoylation of D-hamamelose using vinyl benzoate (4 equiv.) and Lipozyme TL IM as a biocatalyst in t-butyl methyl ether (t-BuMeO) gave mainly benzoylated furanoses (89%), of which tribenzoates reached (52%). Enzymatic galloylation of 2,3-O-isopropylidene-α,β-D-hamamelofuranose with vinyl gallate under the catalysis of Lipozyme TL IM in t-butyl alcohol (t-BuOH) or t-BuMeO provided only the 5-O-galloylated product. The reaction in t-BuMeO proceeded in a shorter reaction time (61 h) and higher yield (82%). The more hydrophobic vinyl 3,4,5-tri-O-acetylgallate in the same reactions gave large amounts of acetylated products. Vinyl gallate and triacetylgallate in the enzymatic acylation of D-hamamelose with Lipozyme TL IM in t-BuMeO yielded 2′,5-diacylated hamamelofuranoses in a yield below 20%. The use of other vinyl gallates hydrophobized by methylation or benzylation provided 2′,5-diacylated hamamelofuranoses in good yields (65–84%). The reaction with silylated vinyl gallate did not proceed. The best results were obtained with vinyl 2,3,5-tri-O-benzyl gallate, and the only product, 2′,5-diacylated hamamelofuranoside precipitated from the reaction mixture (84% in 96 h). After debenzylation, hamamelitannin was obtained an 82% yield from hamamelose in two steps. This synthesis is preparatively undemanding and opens the way to multigram preparations of bioactive hamamelitannin and its analogues.

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.