Wound healing potential of extract from Sambucus nigra L. leaves and its fractions

ETHNOPHARMACOLOGICAL RELEVANCE

Sambucus nigra L. (Viburnaceae), commonly known as black elderberry, is a native species throughout Europe and Western Asia. Elderberry leaves have been used in traditional European medicine, mainly externally, to treat skin and mucosal diseases. They are usually used as decoctions for washing hemorrhoids, ulcers, insect bites, wounds, scrapes, and gingivitis.

AIM OF THE STUDY

Our work aimed to scientifically verify the traditional use of the plant material in treating wounds and skin inflammations accompanied by its phytochemical characterization.

MATERIALS AND METHODS

The effect of 70% (v/v) ethanolic extract and its fractions of different polarities on the inflammatory response of cells involved in wound healing (fibroblasts, keratinocytes, and neutrophils) was investigated. In addition, their effect on the migration of keratinocytes to the scratch site in an in vitro wound healing assay and their impact on the activity of the enzymes involved in skin inflammation, were assessed. The chemical composition was analyzed by UHPLC-DAD-MSn, and the structure of the isolated compounds was determined by NMR.

RESULTS

The supportive effect of the elderberry leaves extract towards wound healing and modulation of the inflammatory response was demonstrated by induction of the keratinocytes. Additionally, the extract was shown to affect the cellular secretion of TNF-α and interleukins -1β, -6, and -8. Examinations of fractionated extract have shown that active principles were mainly contained in dichloromethane fraction. Eleven chemical constituents belonging to flavonoids, cyanogenic glycosides, and lignans were isolated and characterized.

CONCLUSION

The beneficial effect of S. nigra leaves in treating skin diseases has been partially verified and supports its traditional use in skin ailments of different etiologies.

Skin microbiota metabolism of natural products from comfrey root (Symphytum officinale L.)

ETHNOPHARMACOLOGICAL RELEVANCE

Comfrey root (Symphytum officinale L., Boraginaceae) has been used in folk medicine for a long time to treat different diseases. It is recommended for swellings, phlebitis, contusions, gastro-duodenal ulcers, respiratory diseases, and metrorrhagia. Currently, preparations from S. officinale are only topically used due to its wound-healing effects, and for reducing inflammation and the treatment of broken bones, tendon damage, painful joints and muscles. Although it is a widespread plant material, little is known about the interaction of externally applied preparations of comfrey with the human skin microbiome.

AIM OF THE STUDY

The study aims to determine the interaction between human skin microbiota and the comfrey root extracts, by monitoring the biotransformation of the constituents present in the extract and evaluating changes in the population of the skin microbiota in an ex vivo setting.

MATERIAL AND METHODS

The comfrey root extract was incubated with the human skin microbiota from ten healthy donors. The UHPLC-DAD-MSn analysis determined the composition of the raw extract and the microbial metabolites. Bacterial genomic DNA was extracted and examined by amplification sequencing of the 16S rDNA to determine changes in the bacterial composition.

RESULTS

The hydroethanolic extract of comfrey root primarily consists of phenolic acids, pyrrolizidine alkaloids, and their derivatives, and lignans. The natural products present in the extract underwent biodegradation by the skin microbiota, leading to the formation of smaller molecules. It was observed that the skin microbial metabolism primarily focused on modifying the derivatives of pyrrolizidine alkaloids. It resulted in the production of deacetylated and deesterificated compounds. However, it did not lead to the conversion of these compounds into free alkaloids.

CONCLUSIONS

The microbiota-triggered biotransformation of the comfrey root extract was observed. A few N-oxides were metabolized to deacetylated and deesterificated forms in ex vivo conditions. It suggests that the intermittent external applications of comfrey preparations perchance are unlikely to pose a substantial risk. While it even may serve as a potential factor influencing the extract activity in treating skin diseases.

Urolithin A conjugation with NSAIDs inhibits its glucuronidation and maintains improvement of Caco-2 monolayers' barrier function

Urolithin A (UA) is an ellagitannin-derived postbiotic metabolite which emerged as a promising health-boosting agent, promoting mitophagy, improving skeletal muscle function, and suppressing the inflammatory response. However, phase II intestinal metabolism severely limits its biopotency, leading to the formation of nonactive glucuronides. To address this constraint, a set of new UA derivatives (UADs), conjugated with nonsteroidal anti-inflammatory drugs (NSAIDs), was synthesized. The bioavailability and inhibitory activity of UADs against UA-glucuronidation were evaluated using differentiated Caco-2 cell monolayers. Parallelly, after the administration of tested substances, the transepithelial electrical resistance (TEER) of the cell monolayers was continuously monitored using the CellZscope device. Though investigated UADs did not penetrate Caco-2 monolayers, all of them significantly suppressed the glucuronidation rate of UA, while conjugates with diclofenac increased the concentration of free molecule on the basolateral side. Moreover, esters of UA with diclofenac (DicloUA) and aspirin (AspUA) positively influenced cell membrane integrity. Western blot analysis revealed that some UADs, including DicloUA, increased the expression of pore-sealing tight junction proteins and decreased the level of pore-forming claudin-2, which may contribute to their beneficial activity towards the barrier function. To provide comprehensive insight into the mechanism of action of DicloUA, Caco-2 cells were subjected to transcriptomic analysis. Next-generation sequencing (NGS) uncovered substantial changes in the expression of genes involved, for instance, in multivesicular body organization and zinc ion homeostasis. The results presented in this study offer new perspectives on the beneficial effects of modifying UA's structure on its intestinal metabolism and bioactivity in vitro.

Chemical Composition and Insulin-Resistance Activity of Arginine-Loaded American Cranberry (Vaccinium macrocarpon Aiton, Ericaceae) Leaf Extracts

One of the key pathogenetic links in type 2 diabetes mellitus (T2DM) is the formation of insulin resistance (IR). Besides a wide selection of synthetic antidiabetic drugs, various plant-origin extracts are also available to support the treatment of T2DM. This study aimed to investigate and gain knowledge of the chemical composition and potential IR correction effect of American cranberry (Vaccinium macrocarpon Aiton) leaf extracts and formulate novel 3D-printed oral dosage forms for such extracts. The bioactivity and IR of L-arginine-loaded cranberry leaf extracts were studied in vivo in rats. The cranberry leaf extracts consisted of quinic, 3-caffeoylquinic (chlorogenic), p-coumaroylquinic acids, quercetin 3-O-galactoside, quercetin-3-O-glucoside, quercetin-3-xyloside, quercetin-3-O-arabino pyranoside, quercetin-3-O-arabinofuranoside, quercetin 3-O-rhamnoside, and quercetin-O-p-coumaroyl hexoside-2 identified by HPLC. In vivo studies with rats showed that the oral administration of the cranberry leaf extracts had a positive effect on insulin sensitivity coefficients under the insulin tolerance test and affected homeostasis model assessment IR levels and liver lipid content with experimental IR. A novel 3D-printed immediate-release dosage form was developed for the oral administration of cranberry leaf extracts using polyethylene oxide as a carrier gel in semi-solid extrusion 3D printing. In conclusion, American cranberry leaf extracts loaded with L-arginine could find uses in preventing health issues associated with IR.

Therapeutic Effects of Oral Application of Menthol and Extracts from Tormentil (Potentilla erecta), Raspberry Leaves (Rubus idaeus), and Loosestrife (Lythrum salicaria) during Acute Murine Campylobacteriosis

Human food-borne infections with the enteropathogen Campylobacter jejuni are becoming increasingly prevalent worldwide. Since antibiotics are usually not indicated in campylobacteriosis, alternative treatment regimens are important. We here investigated potential disease-alleviating effects of menthol and of extracts from tormentil, raspberry leaves, and loosestrife in acute murine campylobacteriosis. Therefore, C. jejuni-infected microbiota-depleted IL-10-/- mice were orally treated with the compounds alone or all in combination from day 2 until day 6 post-infection. Whereas neither treatment regimen affected gastrointestinal pathogen loads, the combination of compounds alleviated C. jejuni-induced diarrheal symptoms in diseased mice on day 6 post-infection. Furthermore, the therapeutic application of tormentil and menthol alone and the combination of the four compounds resulted in lower colonic T cell numbers in infected mice when compared to placebo counterparts. Notably, pro-inflammatory cytokines measured in mesenteric lymph nodes taken from C. jejuni-infected mice following tormentil, menthol, and combination treatment did not differ from basal concentrations. However, neither treatment regimen could dampen extra-intestinal immune responses, including systemic pro-inflammatory cytokine secretion on day 6 post-infection. In conclusion, the combination of menthol and of extracts from tormentil, raspberry leaves, and loosestrife constitutes an antibiotic-independent approach to alleviate campylobacteriosis symptoms.

Detailed metabolite profiling and in vitro studies of Urospermum picroides as a potential functional food

Wild edible plants (WEP) are part of the Mediterranean culinary culture and can be used as famine foods in times of severe food shortages. Urospermum picroides is a WEP that grows under harsh conditions and represents an opportunity to expand and diversify the global food supply. However, little is known about its chemical profile. In this study, liquid chromatography coupled to HRESIMS allowed the identification of 77 metabolites in U. picroides extract, among which 12 sesquiterpene-amino acid conjugates are reported here for the first time. Due to the novelty of these conjugates, GNPS molecular networking was used to provide information on their fragmentation pathway. Further, the sesquiterpene enriched U. picroides extract showed a moderate anti-inflammatory effect in LPS-stimulated THP1-macrophages by increasing IL-10 secretion while decreasing pro-inflammatory IL-6 secretion at 50 µg/mL. Our study provides evidence for the potential use of U. picroides as an anti-inflammatory functional food and nutraceutical agent.

Phytotherapy of mood disorders in the light of microbiota-gut-brain axis

BACKGROUND

Clinical research in natural product-based psychopharmacology has revealed a variety of promising herbal medicines that may provide benefit in the treatment of mild mood disorders, however failed to unambiguously indicate pharmacologically active constituents. The emerging role of the microbiota-gut-brain axis opens new possibilities in the search for effective methods of treatment and prevention of mood disorders.

PURPOSE

Considering the clinically proven effectiveness juxtaposed with inconsistencies regarding the indication of active principles for many medicinal plants applied in the treatment of anxiety and depression, the aim of the review is to look at their therapeutic properties from the perspective of the microbiota-gut-brain axis.

METHOD

A literature-based survey was performed using Scopus, Pubmed, and Google Scholar databases. The current state of knowledge regarding Hypericum perforatum, Valeriana officinalis, Piper methysticum, Passiflora incarnata, Humulus lupulus, Melissa officinalis, Lavandula officinalis, and Rhodiola rosea in terms of their antimicrobial activity, bioavailability, clinical effectiveness in depression/anxiety and gut microbiota - natural products interaction was summarized and analyzed.

RESULTS

Recent studies have provided direct and indirect evidence that herbal extracts and isolated compounds are potent modulators of gut microbiota structure. Additionally, some of the formed postbiotic metabolites exert positive effects and ameliorate depression-related behaviors in animal models of mood disorders. The review underlines the gap in research on natural products - gut microbiota interaction in the context of mood disorders.

CONCLUSION

Modification of microbiota-gut-brain axis by natural products is a plausible explanation of their therapeutic properties. Future studies evaluating the effectiveness of herbal medicine and isolated compounds in treating mild mood disorders should consider the bidirectional interplay between phytoconstituents and the gut microbiota community.

Application of In Vitro Models for Studying the Mechanisms Underlying the Obesogenic Action of Endocrine-Disrupting Chemicals (EDCs) as Food Contaminants-A Review

Obesogenic endocrine-disrupting chemicals (EDCs) belong to the group of environmental contaminants, which can adversely affect human health. A growing body of evidence supports that chronic exposure to EDCs can contribute to a rapid increase in obesity among adults and children, especially in wealthy industrialized countries with a high production of widely used industrial chemicals such as plasticizers (bisphenols and phthalates), parabens, flame retardants, and pesticides. The main source of human exposure to obesogenic EDCs is through diet, particularly with the consumption of contaminated food such as meat, fish, fruit, vegetables, milk, and dairy products. EDCs can promote obesity by stimulating adipo- and lipogenesis of target cells such as adipocytes and hepatocytes, disrupting glucose metabolism and insulin secretion, and impacting hormonal appetite/satiety regulation. In vitro models still play an essential role in investigating potential environmental obesogens. The review aimed to provide information on currently available two-dimensional (2D) in vitro animal and human cell models applied for studying the mechanisms of obesogenic action of various industrial chemicals such as food contaminants. The advantages and limitations of in vitro models representing the crucial endocrine tissue (adipose tissue) and organs (liver and pancreas) involved in the etiology of obesity and metabolic diseases, which are applied to evaluate the effects of obesogenic EDCs and their disruption activity, were thoroughly and critically discussed.

Current Knowledge on Interactions of Plant Materials Traditionally Used in Skin Diseases in Poland and Ukraine with Human Skin Microbiota

Skin disorders of different etiology, such as dermatitis, atopic dermatitis, eczema, psoriasis, wounds, burns, and others, are widely spread in the population. In severe cases, they require the topical application of drugs, such as antibiotics, steroids, and calcineurin inhibitors. With milder symptoms, which do not require acute pharmacological interventions, medications, dietary supplements, and cosmetic products of plant material origin are gaining greater popularity among professionals and patients. They are applied in various pharmaceutical forms, such as raw infusions, tinctures, creams, and ointments. Although plant-based formulations have been used by humankind since ancient times, it is often unclear what the mechanisms of the observed beneficial effects are. Recent advances in the contribution of the skin microbiota in maintaining skin homeostasis can shed new light on understanding the activity of topically applied plant-based products. Although the influence of various plants on skin-related ailments are well documented in vivo and in vitro, little is known about the interaction with the network of the skin microbial ecosystem. The review aims to summarize the hitherto scientific data on plant-based topical preparations used in Poland and Ukraine and indicate future directions of the studies respecting recent developments in understanding the etiology of skin diseases. The current knowledge on investigations of interactions of plant materials/extracts with skin microbiome was reviewed for the first time.

Tiliae flos metabolites and their beneficial influence on human gut microbiota biodiversity ex vivo

ETHNOPHARMACOLOGICAL RELEVANCE

The linden flower (Tiliae flos) has been used for centuries to treat and relieve symptoms of the common cold, throat irritation, and upper respiratory tract disturbances. Traditionally, this herb is administered orally, and thus it undergoes intestinal metabolism. Although it is pharmacopeial plant material, there are no reports about its interaction with human gut microbiota.

AIM OF THE STUDY

The study aimed to determine the interaction between human gut microbiota and the linden flower extracts, resulting in the biotransformation of the extract's constituents and changes in the microbiota composition.

MATERIAL AND METHODS

The linden flower metabolites were obtained by incubation of extract with human faecal slurries from 5 healthy donors. The UHPLC-DAD-MSⁿ analysis determined the composition of raw extract and analysis of microbial metabolites. The intestinal microbiota isolation and sequencing were used to determine changes in microbiota composition. The anti-inflammatory activity was tested using the LPS-stimulated human neutrophils model and ELISA test.

RESULTS

After incubation of linden flower extract with human gut microbiota, twenty metabolites were detected and characterized, and three among them were identified. The extract changed human gut microbiota composition but did not cause dysbiosis (change in the abundance of forty-three genera). Raw extract and their metabolites exhibit different levels of inhibition of cytokines production by LPS-stimulated neutrophils, but the reduction of TNF-α production was observed.

CONCLUSIONS

The linden flower extract has a beneficial influence on human gut microbiota because it promotes increasing the abundance of bacteria responsible for SCFAs production. The anti-inflammatory effect might be linked to both microbiota composition changes and direct activity of bioavailable metabolites. Increased abundance of SCFAs producers may inhibit the production of pro-inflammatory cytokines. A low concentration of phenolic compounds in metabolized linden flower extract and responsible for anti-inflammatory properties, and the multitude of biological and chemical particles and their interactions may weaken these properties.

Conjugates of urolithin A with NSAIDs, their stability, cytotoxicity, and anti-inflammatory potential

Urolithin A (UA, 1), a gut microbiota postbiotic metabolite is attributed to express interesting biological activities indicated by in vitro, in vivo and clinical studies. Due to its strong anti-inflammatory properties it is considered as a promising lead molecule for further drug development, however, its strong phase II metabolism, severely limits its oral application. Therefore, monoesterified UA derivatives with selected NSAIDs: ibuprofen (Mix 3a/3b), mefenamic acid (Mix 4a/4b), diclofenac (Mix 5a/5b) and aspirin (Mix 6a/6b) were designed. Performed array of stability assays indicated Mix 4a/4b as a most suitable candidate for further studies due to its exceptional stability in human plasma. Thus, we evaluated effects of Mix 4a/4b on cell viability as well as the impact on cytokines secretion in THP-1 derived macrophages and compared it to UA. At high concentration (50 µM) Mix 4a/4b expressed a cytotoxic effect, however at concentration of 5 µM it significantly suppressed TNF-α secretion, and significantly increased ani-inflammatory IL-10 secretion at 10 µM without affecting cell viability. This work has led to selection of a novel UA derivatives, which are stable in solutions and in human plasma as well as posess anti-inflammatory activity towards THP-1 macrophages at non-cytotoxic concentrations.

Gut Microbiota of Pigs Metabolizes Extracts of Filipendula ulmaria and Orthosiphon aristatus-Herbal Remedies Used in Urinary Tract Disorders

Urinary tract infections influence the mortality rate in pigs and are linked to extensive antibiotic usage in the farm industry. Filipendula ulmaria (L.) Maxim. and Orthosiphon aristatus (Blume) Miq. are widespread medicinal plants traditionally used to treat urinary tract disorders. As their preparations are orally administered, the metabolism of their constituents by gut microbiota before absorption should be considered. Until now, no experiments had been performed to describe the biotransformation of tthose plants' extracts by animal gut microbiota. The study evaluates the influence of pig intestinal microbiota on the structure of active compounds in flowers of F. ulmaria and leaves of O. aristatus. The incubations of the extracts with piglet gut microbiota were performed in anaerobic conditions, and the samples of the batch culture were collected for 24 h. In F. ulmaria, the main metabolites were quercetin and kaempferol, which were products of the deglycosylation of flavonoids. After 24 h incubation of O. aristatus extract with the piglet gut microbiota, 2 main metabolites were observed. One, tentatively identified as 3-(3-dihydroxyphenyl)propionic acid, is likely the primary metabolite of the most abundant depsides and phenolic acids. The results confirm the formation of the compounds with anti-inflammatory and diuretic activity in the microbiota cultures, which might suggest F. ulmaria and O. aristatus for treating urinary tract disorders in piglets. Based on the similarities of human and pig gut microbiota, the pig model can help estimate the metabolic pathways of natural products in humans.

Dietary polyphenol and microbiota interactions in the context of prostate health

Recent data strongly indicate a relationship between prostate health and gut microbiota, in which composition and physiological function strictly depend on dietary patterns. The bidirectional interplay of foods containing polyphenols, such as ellagitannins, condensed tannins, lignans, isoflavones, and prenylated flavonoids with human gut microbiota, has been proven to contribute to their impact on prostate health. Considering the attributed role of dietary polyphenols in the prevention of prostate diseases, this paper aims to critically review the studies concerning the influence of polyphenols' postbiotic metabolites on processes associated with the pathophysiology of prostate diseases. Clinical, in vivo, and in vitro studies on polyphenols have been juxtaposed with the current knowledge regarding their pharmacokinetics, microbial metabolism, and potential interactions with microbiota harboring different niches of the human organism. Directions of future research on dietary polyphenols regarding their interaction with microbiota and prostate health have been indicated.

Highbush Blueberry (Vaccinium corymbosum L.) Leaves Extract and Its Modified Arginine Preparation for the Management of Metabolic Syndrome-Chemical Analysis and Bioactivity in Rat Model

Growing blueberry (Vaccinium corymbosum L., Highbush blueberry) as a berry crop is developing dynamically, especially in warm temperate, subtropical, and tropical regions of the world. When blueberry is cultivated on plantations, the bushes are pruned annually, and tons of leaves become waste. Thus, the aim of the present study was to create a preparation from blueberry leaves, study their chemical composition and determine their potential as a dietary supplement for the prophylactic and correction of the metabolic syndrome. Several schemes for obtaining extracts from blueberry leaves have been developed, including one with addition of arginine. A total of 18 phenolic substances were identified and quantified in the extracts by TLC and HPLC methods. Chlorogenic acid, hyperoside, and rutin were shown to be dominating constituents. Quantitative determination of hydroxycinnamic acid derivatives, flavonoids and other phenolics in the extracts was performed by spectrophotometric method. The extracts administration led to a significant decrease in the level of glucose, insulin and triacylglycerols in blood serum of adult mature inbred rats with insulin resistance induced by the fructose-enriched diet. The most promising one was the extract modified with arginine. The determined hypoglycemic and hypolipidemic activity of chemically standardized extracts from highbush blueberry leaves indicate the potential of this crop residue in utilization as a dietary supplement recommended in prevention of ailments associated with metabolic syndrome.

Antiadhesive activity of hydroethanolic extract from bean pods of Phaseolus vulgaris (common bean) against uropathogenic E. coli and permeability of its constituents through Caco-2 cells monolayer

ETHNOPHARMACOLOGICAL RELEVANCE

Phaseaoli pericarpium (bean pods) is a pharmacopeial plant material traditionally used as a diuretic and antidiabetic agents. Diuretic activity of pod extracts was reported first in 1608. Since then Phaseoli pericarpium tea figures in many textbooks as medicinal plant material used by patients.

AIM OF THE STUDY

Despite the traditional use of extracts from Phaseolium vulgaris pericarp, limited information is available on bioactivity, chemical composition, and bioavailability of such preparations. The following study aimed to investigate the phytochemical composition, the in vitro permeability of selected extract's constituents over the Caco-2 permeation system, and potential antivirulence activity against uropathogenic Escherichia coli of a hydroalcoholic Phaseoli pericarpium extract (PPX) in vitro to support its traditional use as a remedy used in urinary tract infections.

MATERIAL AND METHODS

The chemical composition of the extract PPX [ethanol:water 7:3 (v/v)] investigated by using UHPLC-DAD-MSⁿ and subsequent dereplication. The permeability of compounds present in PPX was evaluated using the Caco-2 monolayer permeation system. The influence of PPX on uropathogenic E. coli (UPEC) strain NU14 proliferation and against the bacterial adhesion to T24 epithelial cells was determined by turbidimetric assay and flow cytometry, respectively. The influence of the extract on the mitochondrial activity of T24 host cells was monitored by MTT assay.

RESULTS

LC-MSⁿ investigation and dereplication, indicated PPX extract to be dominated by a variety of flavonoids, with rutin as a major compound, and soyasaponin derivatives. Rutin, selected soyasaponins and fatty acids were shown to permeate the Caco-2 monolayer system, indicating potential bioavailability following oral intake. The extract did not influence the viability of T24 cells after 1.5h incubation at 2 mg/mL and UPEC. PPX significantly reduced the bacterial adhesion of UPEC to human bladder cells in a concentration-dependent manner (0.5-2 mg/mL). Detailed investigations by different incubation protocols indicated that PPX seems to interact with T24 cells, which subsequently leads to reduced recognition and adhesion of UPEC to the host cell membrane.

CONCLUSIONS

PPX is characterised by the presence of flavonoids (e.g. rutin) and saponins, from which selected compounds might be bioavailable after oral application, as indicated by the Caco-2 permeation experiments. Rutin and some saponins can be considered as potentially bioavailable after the oral intake. The concentration-dependent inhibition of bacterial adhesion of UPEC to T24 cells justifies the traditional use of Phaseoli pericarpium in the prevention and treatment of urinary tract infections.

Gut microbiota metabolism and the permeability of natural products contained in infusions from herb of European goldenrod Solidago virgaurea L

ETHNOPHARMACOLOGICAL RELEVANCE

Solidago virgaurea L. (also known as European goldenrod) is a pharmacopoeial plant material popularly used by patients in the form of an infusion. It was traditionally used in Europe and North America for the treatment of urinary tract conditions. It is also reported as a topical agent for skin disorders.

AIM OF THE STUDY

Gut microbiota metabolism plays a crucial role in the bioavailability of natural products contained in plant extracts taken orally. The aim of the current study was to establish the biotransformation of compounds contained in an infusion from goldenrod using human and piglet fecal microbiota in vitro. The permeability of unmetabolized natural products and gut microbiota metabolites was evaluated using a Caco-2 cell model. Preliminary anti-inflammatory assays of raw extract using human neutrophils were also established.

MATERIAL AND METHODS

An infusion was prepared from Solidaginis virgaureae herba commercially available on the market. The characterization of the raw extract was performed by UHPLC-DAD-MS method. The infusion was incubated with human or swine fecal samples in anaerobic conditions. Metabolism products were analyzed and identified by UHPLC-DAD-MS technique. The permeability of the natural products contained in the raw infusion and after metabolism was checked by UHPLC method. The influence of raw extracts on proinflammatory functions of human neutrophils after LPS stimulation was established by flow cytometry and ELISA.

RESULTS

The experiments showed that goldenrod infusion contains mainly caffeoylquinic acid derivatives, flavonoids, and some phenylpropanoids. Natural products present in the extract were transformed by human and swine microbiota to smaller molecules mainly phenylpropanoid acid derivatives. The permeability assays showed that most of the parental compound present in the infusion cannot cross the gut epithelial barrier. In contrast, metabolites were able to cross the Caco-2 monolayer. Depending on the structure, different possible mechanisms of transport were observed. The infusion did not significantly influence the proinflammatory functions of human neutrophils.

CONCLUSIONS

Following oral administration of goldenrod infusion, phytochemicals are prone to undergoing metabolism by gut microbiota to smaller phenylpropionic acid derivatives that can be bioavailable after crossing the gut epithelial barrier to be further metabolized and distributed. Detected metabolites should be considered as potentially active compounds responsible for the bioactivity of the raw plant material in vivo.

High molecular pyrogens present in plant extracts interfere with examinations of their immunomodulatory properties in vitro

The widely accepted strategy to justify the use of medicinal plant extracts in diseases with inflammatory background is their examination on in vitro models using immune cells. It is also a key initial step of research for active principles, which could be then isolated and tested on more advanced models, becoming new pharmacologically active lead molecules. The crucial aspect which has not been so far addressed in this context, is the presence of pyrogens in plant preparations. The aim of this study was the examination of pyrogens interference with in vitro evaluation of anti-inflammatory activity of plant extracts using human primary neutrophils model together with introduction of effective method of interfering factors elimination. The obtained results showed that chosen plant extracts contained pyrogens, which were responsible for concentration-dependent stimulation of pro-inflammatory cytokines production by human neutrophils in vitro in the same extent as LPS did. The ultrafiltration method was successfully applied for pyrogens elimination, which effectiveness was confirmed using LAL test. The determined interference of pyrogens implies the necessity of their consideration and removal when in vitro studies include direct addition of plant extracts to the cell culture, what can be obtained by ultrafiltration, which does not affect extract composition.

Lythrum salicaria Ellagitannins Stimulate IPEC-J2 Cells Monolayer Formation and Inhibit Enteropathogenic Escherichia coli Growth and Adhesion

Lythrum salicaria herb (LSH) was applied in diarrhea therapy since ancient times. Despite empirically referenced therapeutic effects, the bioactivity mechanisms and chemical constituents responsible for pharmacological activity remain not fully resolved. Taking into consideration the historical use of LSH in treatment of diarrhea in humans and farm animals, the aim of the study was to examine in vitro the influence of LSH and its C-glycosylic ellagitannins on processes associated with maintaining intestinal epithelium integrity and enteropathogenic Escherichia coli (EPEC) growth and adhesion. LSH was not only inhibiting EPEC growth in a concentration dependent manner but also its adhesion to IPEC-J2 intestinal epithelial cell monolayers. Inhibitory activity toward EPEC growth was additionally confirmed ex vivo in distal colon samples of postweaning piglets. LSH and its dominating C-glycosylic ellagitannins, castalagin (1), vescalagin (2), and salicarinins A (3) and B (4) were stimulating IPEC-J2 monolayer formation by enhancing claudin 4 production. Parallelly tested gut microbiota metabolites of LSH ellagitannins, urolithin C (5), urolithin A (6), and its glucuronides (7) were inactive. The activities of LSH and the isolated ellagitannins support its purported antidiarrheal properties and indicate potential mechanisms responsible for its beneficial influence on the intestinal epithelium.

Lythrum salicaria L. herb and gut microbiota of healthy post-weaning piglets. Focus on prebiotic properties and formation of postbiotic metabolites in ex vivo cultures

ETHNOPHARMACOLOGICAL RELEVANCE

Herb of purple loosestrife (Lythrum salicaria L. from Lythraceae family) (LSH) was used in Europe since ancient times till early-20th century in the therapy of diarrhea and dysentery in human and veterinary medicine. Post-weaning diarrhea is a main problem affecting global piglet production, which leads to significant economic losses because of increased morbidity and mortality, reduced average daily gain, and high antibiotic consumption. Post-weaning diarrhea has various causes, all of which have been linked to imbalances of intestinal microbiota. The aim of the present study was to determine the interaction of LSH with the gut microbiota of healthy post-weaning piglets in order to evaluate its influence on microbiota composition and metabolism as well as production of potentially bioactive postbiotic metabolites from the extract constituents.

MATERIALS AND METHODS

Ex vivo anaerobic cultures of piglets intestinal microbiota obtained from jejunum, ileum, caecum and distal colon were conducted in various culture media supplemented with LSH. The production of postbiotic metabolites was determined using UPLC-DAD-MSn method. Bacterial genomic DNA was extracted and examined by sequencing by amplification of the 16S rDNA V3-V4 hypervariable regions followed by bioinformatic analysis. The production of SCFA in cultures was determined by GC analysis.

RESULTS

Only the caecal and distal colon microbiota was able to hydrolyze and metabolize ellagitannins present in LSH to urolithins. Urolithin M6, M7, urolithin C, A and iso-urolithin A were detected together with a previously not described metabolite originating from the flavogalloyl moiety of C-glucosylic ellagitannins. LSH had no significant influence on microbiota diversity and metabolic activity, but was able to modulate its composition by significant decrease in Collinsella, Senegalimassilia, uncultured bacteria belonging to Porphyromonadaceae, Rikenellaceae RC9 gut group, Mogibacterium, Dorea, Lachnoclostridium, Lachnospiraceae UCG-004 group, Moryella, [Eubacterium] coprostanoligenes, Intestinimonas, Ruminococcaceae UCG-005, uncultured bacteria belonging to Ruminococcaceae, Acidaminococcus and Allisonella, while the relative abundance of Prevotella, Agathobacter, [Eubacterium] hallii group, Lachnospiraceae NK3A20 group, [Ruminococcus] torques group, Catenibacterium, Catenisphaera and Megasphaera increased. Significant correlations between taxa abundance and production of urolithins were determined.

CONCLUSIONS

In the present study we have shown, that Lythrum salicaria herb fulfills the criteria of a potential candidate for antidiarrheal agent, which could be applied as therapy or prevention of post-weaning diarrhea in piglets. It not only modulates the gut microbiota composition without causing the dysbiosis and impairing metabolic activity, but is also a source of postbiotic metabolites, namely urolithins, which anti-inflammatory properties can be beneficial for gut health of piglets during the weaning period.

Comparative studies of urolithins and their phase II metabolites on macrophage and neutrophil functions

Purpose

Ellagitannins are high molecular weight polyphenols present in high quantities in various food products. They are metabolized by human and animal gut microbiota to postbiotic metabolites-urolithins, bioavailable molecules of a low molecular weight. Following absorption in the gut, urolithins rapidly undergo phase II metabolism. Thus, to fully evaluate the mechanisms of their biological activity, the in vitro studies should be conducted for their phase II conjugates, mainly glucuronides. The aim of the study was to comparatively determine the influence of urolithin A, iso-urolithin A, and urolithin B together with their respective glucuronides on processes associated with the inflammatory response.

Methods

The urolithins obtained by chemical synthesis or isolation from microbiota cultures were tested with their respective glucuronides isolated from human urine towards modulation of inflammatory response in THP-1-derived macrophages, RAW 264.7 macrophages, PBMCs-derived macrophages, and primary neutrophils.

Results

Urolithin A was confirmed to be the most active metabolite in terms of LPS-induced inflammatory response inhibition (TNF-α attenuation, IL-10 induction). The observed strong induction of ERK1/2 phosphorylation has been postulated as the mechanism of its action. None of the tested glucuronide conjugates was active in terms of pro-inflammatory TNF-α inhibition and anti-inflammatory IL-10 and TGF-β1 induction.

Conclusion

Comparative studies of the most abundant urolithins and their phase II conjugates conducted on human and murine immune cells unambiguously confirmed urolithin A to be the most active metabolite in terms of inhibition of the inflammatory response. Phase II metabolism was shown to result in the loss of urolithins’ pharmacological properties.

Electronic supplementary material

The online version of this article (10.1007/s00394-020-02386-y) contains supplementary material, which is available to authorized users.

Eupatoriopicrin Inhibits Pro-inflammatory Functions of Neutrophils via Suppression of IL-8 and TNF-alpha Production and p38 and ERK 1/2 MAP Kinases

During chronic inflammation, neutrophils acting locally as effector cells not only activate antibacterial defense but also promote the inflammatory response. Interleukin 8 (IL-8), the main cytokine produced by activated neutrophils, positively correlates with the severity of respiratory tract diseases. By screening European plants traditionally used for treating respiratory tract diseases, we found that extracts of aerial parts of Eupatorium cannabinum inhibit IL-8 release from neutrophils. Using bioassay-guided fractionation, we identified five sesquiterpene lactones, eupatoriopicrin (1), 5'-deoxyeupatoriopicrin (2), hiyodorilactone A (3), 3-hydroxy-5'- O-acetyleupatoriopicrin = hiyodorilactone D (4), and hiyodorilactone B (5), that efficiently (IC₅₀ < 1 μM) inhibited IL-8 and TNF-α release in lipopolysaccharide (LPS)-stimulated human neutrophils. Moreover, all these sesquiterpene lactones suppressed the adhesion of human neutrophils to an endothelial monolayer by downregulating the expression of the β2 integrin CD11b/CD18 on the neutrophil surface. Furthermore, eupatoriopicrin efficiently suppressed LPS-induced phosphorylation of p38 MAPK and ERK and attenuated neutrophil infiltration in the thioglycolate-induced peritonitis model in mice. Altogether, these results demonstrate the potential of the sesquiterpene lactone eupatoriopicrin as a lead substance for targeting inflammation.

Ellagitannins, Gallotannins and their Metabolites- The Contribution to the Anti-Inflammatory Effect of Food Products and Medicinal Plants

The popularity of food products and medicinal plant materials containing hydrolysable tannins (HT) is nowadays rapidly increasing. Among various health effects attributable to the products of plant origin rich in gallotannins and/or ellagitannins the most often underlined is the beneficial influence on diseases possessing inflammatory background. Results of clinical, interventional and animal in vivo studies clearly indicate the antiinflammatory potential of HT-containing products, as well as pure ellagitannins and gallotannins. In recent years a great emphasis has been put on the consideration of metabolism and bioavailability of natural products during examination of their biological effects. Conducted in vivo and in vitro studies of polyphenols metabolism put a new light on this issue and indicate the gut microbiota to play a crucial role in the health effects following their oral administration. The aim of the review is to summarize the knowledge about HT-containing products' phytochemistry and their anti-inflammatory effects together with discussion of the data about observed biological activities with regards to the current concepts on the HTs' bioavailability and metabolism. Orally administered HT-containing products due to the limited bioavailability of ellagitannins and gallotannins can influence immune response at the level of gastrointestinal tract as well as express modulating effects on the gut microbiota composition. However, due to the chemical changes being a result of their transit through gastrointestinal tract, comprising of hydrolysis and gut microbiota metabolism, the activity of produced metabolites has to be taken into consideration. Studies regarding biological effects of the HTs' metabolites, in particular urolithins, indicate their strong and structure-dependent anti-inflammatory activities, being observed at the concentrations, which fit the range of their established bioavailability. The impact of HTs on inflammatory processes has been well established on various in vivo and in vitro models, while influence of microbiota metabolites on silencing the immune response gives a new perspective on understanding anti-inflammatory effects attributed to HT containing products, especially their postulated effectiveness in inflammatory bowel diseases (IBD) and cardiovascular diseases.

The Activity of Urolithin A and M4 Valerolactone, Colonic Microbiota Metabolites of Polyphenols, in a Prostate Cancer In Vitro Model

The gut microbiota-derived metabolites of ellagitannins and green tea catechins, urolithin A (uroA) and 5-(3',4',5'-trihydroxyphenyl)-γ-valerolactone (M4), respectively, are among the main compounds absorbed into human system after ingestion of these polyphenols. The aim of this study was to establish the effects of M4, uroA, and their combinations on LNCaP cells, an androgen dependent prostate cancer in vitro model.. The LNCaP cells were incubated with increasing concentrations of tested metabolites. The cell proliferation was determined by measurement of DNA-bisbenzimide H 33 258 complexes fluorescence. The isobolographic analysis was used to establish the type of interaction between metabolites. The apoptosis, androgen receptor (AR) localization, and phosphorylation of Akt kinase were measured by flow cytometry. Prostate-specific antigen (PSA) secretion was determined by ELISA. M4 showed modest antiproliferative activity in LNCaP cells (IC₅₀ = 117 µM; CI: 81 - 154). UroA decreased proliferation (IC₅₀ = 32.7 µM; CI: 24.3 - 41.1) and induced apoptosis of LNCaP cells. The mixture of M4 with uroA had synergistic antiproliferative effect. Moreover, M4 potentiated inhibition of PSA secretion and enhanced retention of AR in cytoplasm caused by uroA. Interestingly, uroA increased levels of pSer473 Akt in LNCaP cells. These results show that colonic metabolites may contribute to chemoprevention of prostate cancer by varied polyphenol-rich diet or composite polyphenol preparations.

The effects of urolithins on the response of prostate cancer cells to non-steroidal antiandrogen bicalutamide

BACKGROUND

Urolithins are bioavailable products of gut microbiota metabolism of ellagitannins. Their biological activity includes anti-cancer effects.

PURPOSE

The aim of this study was to explore the effects of urolithins on prostate cancer cells and activity of clinically used anti-androgen, bicalutamide.

METHODS

Prostate cancer cells were treated with urolithin A, urolithin B, urolithin C or their combinations with bicalutamide. Cell proliferation was determined by DNA fluorescence with Hoechst 33258. The combination index method was used to examine interactions. Apoptosis and androgen receptor (AR) localization were analysed by flow cytometry. Prostate specific antigen (PSA) secretion was measured by ELISA.

RESULTS

Urolithins inhibited proliferation of LNCaP prostate cancer cells. The mixtures of bicalutamide with uroA and uroB had additive anti-proliferative effect. All tested urolithins induced apoptosis of LNCaP cells. However, the combinations of bicalutamide with urolithin A and urolithin B had attenuated pro-apoptotic activity. UroA and uroC decreased DHT-induced PSA secretion. In contrast, uroB impaired PSA lowering effect of bicalutamide. UroA, individually and in combination with bicalutamide, promoted cytoplasmic localization of AR.

CONCLUSION

Urolithins might contribute to chemopreventive activity of ellagitannin rich preparations. Our results support use of ellagitannin rich preparations in prostate cancer chemoprevention, but advise caution in their potential use in complementary therapy of prostate cancer. The differences in activity profiles of urolithins indicate that possible health benefits and interactions will depend on the type of produced ellagitannins metabolite.

Lignans From Forsythia x Intermedia Leaves and Flowers Attenuate the Pro-inflammatory Function of Leukocytes and Their Interaction With Endothelial Cells

Aim of the study: Taking into account that overactivated leukocytes are an important factor in the development of many chronic diseases, we investigated the activity of phytochemically characterized (HPLC-DAD-MSⁿ) extracts from forsythia leaves and flowers on the pro- and anti-inflammatory functions of leukocytes (effects on IL-1β, IL-8, TNF-α, and TGFβ release) and their adherence to endothelial cells. Using bio-guided fractionation, we isolated the active compounds and determined their biological activity, and we included the positive control quercetin. Methods: The effect on IL-1β, TNF-α, IL-8, and TGF-α production by leukocytes was measured by enzyme-linked immunosorbent assay (ELISA). The surface expression of adhesion molecules was analyzed with flow cytometry, and the neutrophil attachment to the endothelial cells was assessed fluorimetrically. The effects on p38MAPK, ERK1/2 and JNK phosphorylation were determined using western blots. Results: Leaf extracts had the effect of decreasing TNF-α production in neutrophils and monocyte/macrophage cells. The bio-guided fractionation led to the isolation of the following lignan aglycones: (+)-pinoresinol, (+)-epipinoresinol, (-)-matairesinol, (+)-phillygenin, and (-)-arctigenin. Only phillygenin was able to stimulate the anti-inflammatory function of macrophages by inducing TGF-β release and IL-10 receptor surface expression. Arctigenin, phillygenin, and a metabolite produced by the gut microbiota, enterolactone, decreased TNF-α and IL-1β production and neutrophil adhesion to endothelial cells, probably by attenuating the p38 and ERK kinase pathways. Conclusion:Forsythia x intermedia is a valuable source of active lignans, which may be potential candidates for treating inflammatory diseases that are associated with the excessive production of cytokines such as TNF-α and IL-1β.

Evaluation of the Effect of Epilobium angustifolium Aqueous Extract on LNCaP Cell Proliferation in In Vitro and In Vivo Models

Epilobium sp. are commonly used in traditional medicine in the treatment of early stages of benign prostatic hyperplasia and inflammation. It is suggested that a dominating constituent, oenothein B, is responsible for the extracts therapeutic effects. Several bioactivities were established for extracts and oenothein B in various in vitro models, but due to the questionable bioavailability of this dimeric macrocyclic ellagitannin, their significance in the in vivo effects remains unresolved. We have thus focused our attention on a complex comparative investigation of the in vitro and in vivo activities of phytochemically characterized Epilobium angustifolium aqueous extract and oenothein B on prostate cancer cells proliferation.Incubation of different cell lines with E. angustifolium aqueous extract resulted in a significant reduction of proliferation of PZ-HPV-7 and LNCaP cells, which was partly associated with antiandrogenic activity. These effects were fully congruent with oenothein B, examined in parallel. Oral supplementation of rats implanted with LNCaP cells with E. angustifolium aqueous extract 50-200 mg/kg b. w. resulted in a reduction of the occurrence of prostatic adenoma up to 13 %. Oenothein B was not detected in the urine and feces of the E. angustifolium aqueous extract-treated group, however, conjugates of nasutins gut microbiota metabolites of ellagitannins were detected in the urine, while in human volunteers supplemented with Epilobium tea, only urolithin conjugates were present.Despite observing significant and consistent effects in vitro and in vivo, we were unable to point out unequivocally the factors contributing to the observed E. angustifolium aqueous extract activity, facing the problems of an unknown metabolic fate of oenothein B and interspecies differences in E. angustifolium aqueous extract gut microbiota metabolism.

A comprehensive review of agrimoniin

Plant tannins are a unique class of polyphenols with relatively high molecular weights. Within the ellagitannins group, agrimoniin--dimeric ellagitannin--is one of the most representative compounds found in many plant materials belonging to the Rosaceae family. Agrimoniin was first isolated in 1982 from roots of Agrimonia pilosa Ledeb. (Rosaceae), a plant traditionally used in Japan and China as an antidiarrheal, hemostatic, and antiparasitic agent. Agrimoniin is a constituent of medicinal plants, which are often applied orally in the form of infusions, decoctions, or tinctures. It is also present in commonly consumed food products, such as strawberries and raspberries. It is metabolized by human gut microbiota into a series of low-molecular-weight urolithins with proven anti-inflammatory and anticancer in vivo and in vitro bioactivities. The compound has received widespread interest owing to some interesting biological effects and therapeutic activities, which we elaborate in the present review. Additionally, we present an overview of the techniques used for the analysis, isolation, and separation of agrimoniin from the practical perspective.

Monoterpenoids from the traditional North Italian vegetable Aruncus dioicus (Walter) Fernald var. vulgaris (Maxim.) H.Hara (Rosaceae)

Investigations of young shoots of Aruncus dioicus (Walter) Fernald var. vulgaris (Maxim.) H.Hara (Rosaceae), collected from the wild and used as vegetables in alpine provinces of Italy, yielded eight monoterpenoids. Besides known compounds, aruncin A, aruncide A, and cimicifugolide, five previously undescribed substances, aruncins C, D, and E, and aruncides D and E, were identified. Based on results from the full synthesis of aruncin B, structures of aruncin A and aruncide A were revised. Structures were established by HR mass spectrometry and extensive 1D and 2D NMR spectroscopy and based on data from synthetic aruncin B. An HPLC-DAD-ESI-MS method was developed to investigate the distribution of the monoterpenoids in different organs of Aruncus dioicus var. vulgaris and in aerial parts of A. dioicus var. aethusifolius (H.Lév.) H.Hara [Syn.: Aruncus aethusifolius (H.Lév.) Nakai]. Preliminary bioactivity studies moreover indicated weak cytotoxicity for some of the compounds against human prostrate adenocarcinoma cells.

Differences in Metabolism of Ellagitannins by Human Gut Microbiota ex Vivo Cultures

Ellagitannin-rich plant materials are used as popular remedies in the treatment of various inflammatory diseases. Urolithins are gut microbiota metabolites of ellagitannins and are considered responsible for in vivo health effects. Various natural products have been studied that are known sources of urolithins. However, few studies have focused on the metabolism of ellagitannin molecules. The aim of the study was to examine the metabolic fate of select ellagitannins using ex vivo cultures of human gut microbiota. Fifteen monomeric and dimeric ellagitannins, 1-O-galloyl-4,6-(S)-HHDP-β-d-glucose (2), pedunculagin (3), potentillin (4), casuarictin (5), coriariin B (6), vescalagin (7), castalagin (8), stachyurin (9), casuarinin (10), stenophyllinin A (11), stenophyllanin A (12), salicarinin A (13), gemin A (14), agrimoniin (15), and oenothein B (16), and ellagic acid (1) were studied. The formation of the metabolites in ex vivo human microbiota cultures was monitored using UHPLC-DAD-MS/MS. Ellagitannins possessing hexahydroxydiphenoyl moieties were metabolized to 6H-dibenzo[b,d]pyran-6-one derivatives, i.e., urolithins. The observed differences in amounts of produced urolithins indicated that the individual microbiota composition and type of ingested ellagitannins could determine the rate of urolithin production. When the oral ingestion of natural products containing ellagitannins with hexahydroxydiphenoyl groups is considered, the formation of urolithins and their bioactivity should be addressed.

Effects of Geum urbanum L. root extracts and its constituents on polymorphonuclear leucocytes functions. Significance in periodontal diseases

ETHNOPHARMACOLOGICAL RELEVANCE

Geum urbanum L. (wood avens) root infusions and decoctions have been used externally for reducing the bleeding and inflammation of gums (gingivitis), and mucous membranes.

AIM OF THE STUDY

Taking into account that primed and hyperactivated neutrophils are an important factor in the transition from gingivitis to periodontitis, we investigated the effects of phytochemically characterised (HPLC-DAD-MS(n)) extracts of different polarity from Geum urbanum root on oxidative burst, elastase, metalloproteinase 9 (MMP-9), interleukin 8 (IL-8) and 1β (IL-1β), tumour necrosis factor (TNF-α) release, expression of adhesion molecules (CD62L and CD11b) and delayed apoptosis in stimulated neutrophils. As gemin A is a dominating compound in a raw material, so we considered its activity in parallel with the positive control quercetin.

MATERIALS AND METHODS

The extracts were characterised by HPLC-DAD- MS(n) method. The inhibition of ROS production by stimulated neutrophils was determined using luminol dependent chemiluminescence method. The effect on MMP-9, IL-1β, TNF-α and IL-8 production by neutrophils was measured by enzyme-linked immunosorbent assay (ELISA). Neutrophil elastase release was established spectrophotometrically. The expression of adhesion molecules and the apoptosis of neutrophils was analyzed with flow cytometry.

RESULTS

The main compounds detected in the extract belong mainly to the group of ellagitannin: pedunculagin, stachyurin, casuarynin and gemin A, and ellagic acid derivatives. Procyanidins and one complex tannin were found as minor compounds. Gemin A significantly affected the functions of stimulated neutrophils by reducing the surface expression of CD11b, and inhibiting the release of reactive oxygen species, and proteases (elastase, MMP-9), chemokines and cytokines (interleukins IL-8, IL-1β). Interestingly, gemin A stimulated the release of TNF-α, which may be one of the stimulators of apoptosis of neutrophil cells. The primary aqueous extract, the ethyl acetate and the butanolic fractions, all containing the highest level of gemin A, have exerted similar but weaker activity.

CONCLUSION

The modulating effect on the neutrophils function of extracts, and its main constituent gemin A, support the traditional use of this plant material in cavity inflammation including mucositis, gingivitis and periodontosis.

Seasonal variation in secondary metabolites of edible shoots of Buck's beard [Aruncus dioicus (Walter) Fernald (Rosaceae)]

Aruncus dioicus (Walter) Fernald is an herbaceous plant belonging to the Rosaceae family. In the northern regions of Italy young shoots of A. dioicus are collected and used as vegetable. No studies on the chemical composition of young shoots of A. dioicus have been reported so far. Thus, the aim of the present paper was to develop and validate a comprehensive chromatographic method allowing the identification and quantification of chemical compounds occurring in A. dioicus shoots harvested at different developmental stages. The results showed that shoots contain mainly polyphenols. Twenty-four compounds were detected. Caffeoylglucose derivatives were recognized as major compounds. It was also confirmed that shoots contain the cyanogenic compound prunasin at all investigated vegetation stages. It was shown that the prunasin content significantly increases during plant development, thus justifying the belief that after the development of the first green leaves, shoots should not be used for culinary purposes any longer.

Ellagitannins modulate the inflammatory response of human neutrophils ex vivo

BACKGROUND

Tannin-rich plant materials are commonly used in the traditional medicine as external anti-inflammatory, antioxidant and antimicrobial agents. Plant extracts containing significant quantities of tannins are often used in the prevention and treatment of oral cavity diseases such as periodontosis or gingivitis. The contribution of pure ellagitannins to the observed anti-inflammatory activity of tannin-rich remedies is still not resolved.

PURPOSE

The aim of the present study the study was to establish if ellagitannins and their precursor - pentagalloylglucose (1) can modulate the inflammatory response of ex-vivo stimulated neutrophils.

METHODS

Human neutrophils were isolated from the buffy coats obtained from healthy volunteers. Neutrophils were cultivated with or without tested compounds. The influence of ellagitannins and 1 on the production and release of pro-inflammatory factors such as elastase, reactive oxygen species, interleukin-8, tumour necrosis factor alpha (TNF-α) and metalloproteinase-9 was evaluated using ELISA sets or chemical methods. The effect on surface expression of toll like receptor 4 (TLR-4) and apoptosis was also checked using flow cytometry.

RESULTS

The results showed that ellgitannins modulate the inflammatory response of human neutrophils by the inhibition of production and release of chosen cytokines and pro-inflammatory enzymes. By the induction of TNF-α ellagitannins enhance neutrophil apoptosis, which is of interest in the case of chronic inflammation within oral cavity. Ellagitannins also decrease the surface expression of TLR-4 in activated neutrophils.

CONCLUSION

The results support the traditional use of tannin-rich products in the prevention and treatment of oral cavity diseases. The present study proves the substantial contribution of ellagitannins to the anti-inflammatory activity of tannin-rich medicinal plant materials.

Novel stilbenoids, including cannabispiradienone glycosides, from Tragopogon tommasinii (Asteraceae, Cichorieae) and their potential anti-inflammatory activity

A phytochemical investigation of Tragopogon tommasinii Sch.Bip. (Asteraceae, Cichorieae) yielded a total of 21 natural products, two simple phenolic acids (4-hydroxybenzoic acid and p-coumaric acid), four caffeic acid derivatives (chlorogenic acid, 3-O-caffeoylquinic acid, 3,5-O-dicaffeoylquinic acid, and 4,5-O-dicaffeoylquinic acid), six flavonoids (luteolin, luteolin 7-O-glucoside, vitexin, orientin, quercetin 3-O-glucoside, and isorhamnetin 3-O-glucoside), three simple bibenzyls [2-carboxyl-5-hydroxy-3-methoxy-4'-β-glucopyranosyl-oxybibenzyl, 3-caffeoyl-(9→5)-β-apiosyl-(1→6)-β-glucopyranosyloxy-5,4'-dihydroxy-3'-methoxybibenzyl, 3-caffeoyl-(9→5)-β-apiosyl-(1→6)-β-glucopyranosyloxy-4'-dihydroxy-5,3'-dimethoxybibenzyl], three phtalides [3-(4-β-glucopyranosyloxybenzyl)-7-hydroxy-5-methoxyphtalide, 7-β-glucopyranosyloxy-(S)-3-(4-hydroxybenzyl)-5-methoxyphtalide, and 7-(1→6)-α-rhamnosyl-β-glucopyranosyloxy-(S)-3-(4-hydroxybenzyl)-5-methoxyphtalide], two cannabispiradienone derivatives [3-O-β-glucopyranosyldemethoxycannabispiradienone and 3-caffeoyl-(9→5)-β-apiosyl-(1→6)-β-glucopyranosyloxydemethoxycannabispiradienone], and tetra-N-coumaroyl spermine. The three bibenzyls, the latter two benzylphthalides, and both cannabispiradienone derivatives represent new natural compounds and all compounds, except the caffeic acid derivatives and the flavonoids were new for T. tommasinii. The structures were established by HR mass spectrometry, extensive 1D and 2D NMR spectroscopy, and CD spectroscopy. Moreover, the potential anti-inflammatory activities of the new compounds were assayed using human neutrophils and their production of IL-1b, IL-8, TNF-α and MMP-9 as well as the expression of TLR-4, respectively.

Urolithins, gut microbiota-derived metabolites of ellagitannins, inhibit LPS-induced inflammation in RAW 264.7 murine macrophages

SCOPE

Ellagitannin-rich food products and medicinal plant materials were shown to have beneficial effects toward intestinal inflammation. Due to the questionable bioavailability of ellagitannins their gut microbiota metabolites-urolithins have come to be regarded as potential factors responsible for biological activities observed in vivo. The aim of the study was to determine the influence of the three most abundant bioavailable ellagitannin gut microbiota metabolites-urolithins A, B, and C on inflammatory responses in RAW 264.7 murine macrophages, which are involved in the pathogenesis of intestine inflammation.

METHODS AND RESULTS

Urolithins A, B, and C decreased NO production via inhibition of the iNOS protein and mRNA expression. They decreased the expression of IL-1β, TNF-α, and IL-6 mRNA in LPS challenged RAW 264.7 murine macrophages. A clear inhibition of NF-κB p65 nuclear translocation and p50 DNA-binding activity was associated with the observed anti-inflammatory activities of urolithins. Among the tested compounds urolithin A had the strongest anti-inflammatory activity.

CONCLUSION

The anti-inflammatory effects of urolithins at concentrations that are physiologically relevant for gut tissues (≥40 μM), as revealed in this study, support the data from in vivo studies showing the beneficial effects of ellagitannin-rich products toward intestinal inflammation.

Lythrum salicaria L.-Underestimated medicinal plant from European traditional medicine. A review

ETHNOPHARMACOLOGICAL RELEVANCE

Purple loosestrife-Lythrum salicaria L. is a herbaceous perennial plant belonging to the Lythraceae family. It has been used for centuries in European traditional medicine. Despite Lythri herba being a pharmacopoeial plant material (Ph. Eur.), L. salicaria popularity as a medicinal plant has recently declined. The aim of the paper is to recall a traditional and historical use of L. salicaria and juxtapose it with comprehensive view on the current knowledge about its chemical composition and documented biological activities in order to bring back the interest into this valuable plant and indicate reasonable directions of future research and possible applications.

MATERIALS AND METHODS

Systematic survey of historical and ethnopharmacological literature was carried out using sources of European and American libraries. Pharmacological and phytochemical literature research was performed using Scopus, PubMed, Web of Science and Reaxys databases.

RESULTS

The review of historical sources from ancient times till 20th century revealed an outstanding position of L. salicaria in traditional medicine. The main applications indicated were gastrointestinal tract ailments (mainly dysentery and diarrhea) as well as different skin and mucosa affections. The current phytochemical studies have shown that polyphenols (C-glucosidic ellagitannins and C-glucosidic flavonoids) as well as heteropolysaccharides are dominating constituents, which probably determine the observed pharmacological effects. The extracts and some isolated compounds were shown to possess antidiarrheal, antimicrobial, anti-oxidant, anti-inflammatory and anti-diabetic activities.

CONCLUSIONS

The intrinsic literature overview conclusively demonstrates that L. salicaria L. used to be considered as an exceptionally effective remedy in European traditional medicine. Despite its unquestionable important position from unknown reasons its popularity has been weakened during the past few decades. Unfortunately the contemporary pharmacological research is still insufficient to support its thoroughly described traditional uses. The necessity of complex studies regarding modes of action, which would directly refer to L. salicaria main traditional applications-gastrointestinal tract ailments, is strongly underlined.

Polyphenolic Profile, Antioxidant and Anti-Inflammatory Activity of Eastern Teaberry (Gaultheria procumbens L.) Leaf Extracts

Dry leaf extracts of eastern teaberry (Gaultheria procumbens L.) were evaluated as a source of bioactive phytocompounds through systematic activity testing and phytochemical profiling. The antioxidant efficiency was tested using five complementary in vitro models (DPPH; FRAP; linoleic acid (LA) peroxidation assay; O₂^•− and H₂O₂ scavenging tests) in parallel with standard antioxidants. The 75% methanol extract and its diethyl ether, ethyl acetate (EAF), n-butanol and water fractions exhibited the dose-dependent responses in all assays, with the highest capacities found for EAF (DPPH EC₅₀ = 2.9 μg/mL; FRAP = 12.8 mmol Fe²⁺/g; IC₅₀ for LA-peroxidation = 123.9 μg/mL; O₂^•− SC₅₀ = 3.9 μg/mL; H₂O₂ SC₅₀ = 7.2 μg/mL). The EAF had also the highest anti-inflammatory activity in the inhibition tests of lipoxygenase and hyaluronidase (60.14% and 21.83% effects, respectively, at the concentration of 100 μg/mL). Activity parameters of the extracts correlated strongly with the levels of total phenolics (72.4–270.7 mg GAE/g), procyanidins, and phenolic acids, whereas for flavonoids only moderate effects were observed. Comprehensive UHPLC-PDA-ESI-MS³ and HPLC-PDA studies led to the identification of 35 polyphenols with a procyanidin A-type trimer, quercetin 3-O-glucuronide, isomers of caffeoylquinic acids, and (‒)-epicatechin being the dominant components. Significant activity levels, high phenolic contents and high extraction yields (39.4%–42.5% DW for defatted and crude methanol extracts, respectively) indicate the value of eastern teaberry leaves as bioactive products.

Phytochemistry, pharmacology and traditional uses of different Epilobium species (Onagraceae): a review

ETHNOPHARMACOLOGICAL RELEVANCE

The Epilobium genus (willowherb) comprises of ca. 200 species of herbaceous plants distributed around the world. Infusions prepared form willowherbs have been traditionally used externally in skin and mucosa infections and in the treatment of benign prostate hyperplasia. Nowadays extracts from different Epilobium species are widely used by patients, however the lack of clinical studies does not allow to fully establish their efficacy. The present review summarizes published data on phytochemistry, ethnopharmacological use and pharmacological studies concerning willowherb species investigated throughout past few decades.

MATERIALS AND METHODS

Literature survey was performed using Scopus, PubMed, Web of Science and Reaxys databases looking for papers and patents focused on chemical composition and bioactivity of Epilobium species. Systematic research in ethnopharmacological literature in digitalized sources of academic libraries was also carried out.

RESULT

The chemical composition of different Epilobium species and their bioactivities are described. The detailed information on constituents isolated and detected by chromatographic methods is given. The studies show that polyphenols are main compounds occurring in Epilobium herb among which flavonoids, phenolic acids and tannins (oenothein B and oenothein A) are dominating constituents. The extracts and some isolated compounds from Epilobium sp. were shown to possess antimicrobial, anti-proliferative, anti-inflammatory, analgesic and antioxidative activities. Because many studies suggest that oenothein B as dominating constituent may be responsible for Epilobium sp. pharmacological effects, its documented bioactivities were also described.

CONCLUSIONS

The pharmacological studies performed on Epilobium justify the traditional use of this species in external and in gastrointestinal inflammations. As far as the treatment of benign prostate hyperplasia (BPH) is considered, in the literature, there are some reports indicating that Epilobium extracts have a beneficial effect for this disorder, but the number of in vitro studies is not sufficient and the in vivo studies are not conclusive or too preliminary to draw a final conclusion about the efficacy of Epilobium preparations. More in vitro, in vivo and clinical studies to confirm this mode of action are strongly needed. Epilobium's extracts have also documented antioxidative and potential anti-inflammatory properties. Oenothein B can be considered as responsible for some of Epilobium pharmacological properties. Because of the lack of clinical data further studies are needed to provide an evidence base for traditional uses of plant materials belonging to the Epilobium genus.

Contribution of C-glucosidic ellagitannins to Lythrum salicaria L. influence on pro-inflammatory functions of human neutrophils

The herb Lythrum salicaria L. (Lythraceae) is used in traditional medicine to treat diseases with an inflammatory background, such as haemorrhoidal disease, dysentery, chronic intestinal catarrh, eczema, varicose veins, periodontosis and gingivitis. Because these diseases are closely associated with an excessive inflammatory response of stimulated neutrophils, the influence of aqueous extract and isolated C-glucosidic ellagitannins (dimeric salicarinins A, B and C, vescalagin, castalagin) on their pro-inflammatory functions was examined. Lythrum salicaria aqueous extract was shown to modulate lipopolysaccharide (LPS)-triggered production of IL-8 (at 20 μg/mL, 16.6 ± 4.2 % inhibition) but had no influence on MMP-9 production. It was active towards cytochalasin A/f-MLP- stimulated elastase release (at 20 μg/mL, 21.5 ± 3.9 % inhibition), myeloperoxidase release (at 1 μg/mL, 26.5 ± 5.4 % inhibition) and f-MLP- and PMA-induced reactive oxygen species production (at 20 μg/mL, 67.0 ± 3.9 and 66.5 ± 1.9 % inhibition, respectively). The extract was also shown to inhibit expression of integrin CD11b on the neutrophil surface without influencing selectin CD62L shedding. Dose-dependent inhibition of hyaluronidase activity was observed with IC₅₀ = 10.1 ± 1.2 μg/mL. The main C-glucosidic ellagitannins were shown to be responsible for all these activities with more significant participation attributable to dimeric salicarinins A, B, C. This study has demonstrated potent activity of aqueous extract on stimulated neutrophils; this enhanced response is known to cause pathological changes in skin and mucosa tissues. These observations support and explain the traditional use of the herb Lythrum salicaria to treat certain diseases with an inflammatory background. C-glucosidic ellagitannins, especially dimeric salicarinins, are the factors responsible for these effects.

Role of human gut microbiota metabolism in the anti-inflammatory effect of traditionally used ellagitannin-rich plant materials

ETHNOPHARMACOLOGICAL RELEVANCE

Ellagitannin-rich plant materials are widely used in traditional medicine as effective, internally used anti-inflammatory agents. Due to the not well-established bioavailability of ellagitannins, the mechanisms of observed therapeutic effects following oral administration still remain unclear. The aim of the study was to evaluate if selected ellagitannin-rich plant materials could be the source of bioavailable gut microbiota metabolites, i.e. urolithins, together with determination of the anti-inflammatory activity of the metabolites produced on the THP-1 cell line derived macrophages model.

MATERIALS AND METHODS

The formation of urolithins was determined by ex vivo incubation of human fecal samples with aqueous extracts from selected plant materials. The anti-inflammatory activity study of metabolites was determined on PMA differentiated, IFN-γ and LPS stimulated, human THP-1 cell line-derived macrophages.

RESULTS

The formation of urolithin A, B and C by human gut microbiota was established for aqueous extracts from Filipendula ulmaria (L.) Maxim. herb (Ph. Eur.), Geranium pratense L. herb, Geranium robertianum L. herb, Geum urbanum L. root and rhizome, Lythrum salicaria L. herb (Ph. Eur.), Potentilla anserina L. herb, Potentilla erecta (L.) Raeusch rhizome (Ph. Eur.), Quercus robur L. bark (Ph. Eur.), Rubus idaeus L. leaf, Rubus fruticosus L. and pure ellagitannin vescalagin. Significant inhibition of TNF-α production was determined for all urolithins, while for the most potent urolithin A inhibition was observed at nanomolar concentrations (at 0.625 μM 29.2±6.4% of inhibition). Urolithin C was the only compound inhibiting IL-6 production (at 0.625 μM 13.9±2.2% of inhibition).

CONCLUSIONS

The data obtained clearly indicate that in the case of peroral use of the examined ellagitannin-rich plant materials the bioactivity of gut microbiota metabolites, i.e. urolithins, has to be taken under consideration.

Influence of gut microbiota-derived ellagitannins' metabolites urolithins on pro-inflammatory activities of human neutrophils

Ellagitannin-rich products exhibit beneficial influence in the case of inflammation-associated diseases. Urolithins, metabolites of ellagitannins produced by gut microbiota, in contrary to high molecular weight hydrophilic parental polyphenols, possess well established bioavailability. Because of the important role of neutrophils in progression of inflammation, the influence of urolithins on their pro-inflammatory functions was tested. Urolithin B at a concentration of 20 µM showed significant inhibition of interleukin 8 and extracellular matrix-degrading enzyme MMP-9 production. It was also significantly active in prevention of cytochalasin A/formyl-met-leu-phenylalanine-triggered selectin CD62L shedding. Urolithin C was the only active compound towards inhibition of elastase release from cytochalasin A/formyl-met-leu-phenylalanine-stimulated neutrophils with 39.0 ± 15.9% inhibition at a concentration of 5 µM. Myeloperoxidase release was inhibited by urolithins A and C (at 20 µM by 46.7 ± 16.1 and 63.8 ± 8.6%, respectively). Urolithin A was the most potent reactive oxygen species release inhibitor both in formyl-met-leu-phenylalanine and 4β-phorbol-12β-myristate-R13-acetate-stimulated neutrophils. At the concentration of 1 µM, it caused reactive oxygen species level decrease by 42.6 ± 26.6 and 53.7 ± 16.0%, respectively. Urolithins can specifically modulate inflammatory functions of neutrophils, and thus could contribute to the beneficial health effects of ellagitannin-rich medicinal plant materials and food products.

Determination of C-glucosidic ellagitannins in Lythri salicariaeherba by ultra-high performance liquid chromatography coupled with charged aerosol detector: method development and validation

INTRODUCTION

Lythri salicariaeherba is a pharmacopoeial plant material used by patients in the form of infusions in the treatment of acute diarrhoea. According to its pharmacopoeial monograph it is standardised for total tannin content, which should be not less than 5.0% using pyrogallol as a standard. Previous studies have shown that aqueous extracts from Lythri herba contain mainly ellagitannins among which vescalagin, castalagin and salicarinins A and B are dominating constituents.

OBJECTIVE

To develop and validate an efficient UHPLC coupled with a charged aerosol detector (CAD) method for quantification of four major ellagitannins in Lythri salicariaeherba and in one commercial preparation.

METHODS

Extraction conditions of ellagitannins from plant material were optimised. The relative response factors for vescalagin, castalagin and salicarinins A and B using gallic acid as an external standard were determined for the CAD detector. Then, a UHPLC method for quantification of ellagitannins was developed and validated.

RESULTS

Four major ellagitannins were quantified in four samples of Lythri herba and in one commercial preparation. The sum of ellagitannins for each sample was determined, which varied from 30.66 to 48.80 mg/g of raw material and 16.57 mg per capsule for the preparation investigated.

CONCLUSION

The first validated UHPLC/CAD UHPLC-CAD method for quantification of four major ellagitannins was developed. The universality of the CAD response was evaluated and it is shown that although all compounds analysed have similar structures their CAD response differs significantly.

In vitro antioxidant and anti-inflammatory activities of extracts from Potentilla recta and its main ellagitannin, agrimoniin

ETHNOPHARMACOLOGICAL RELEVANCE

Potentilla recta is one of the numerous cinquefoil species growing in Poland. It is used in traditional medicine e.g. in the treatment of skin inflammation.

AIM OF THE STUDY

The purpose of the present study is to evaluate antioxidant and anti-inflammatory activities of extracts and subfractions of the P. recta herb (obtained by using solvents of different polarity) in in vitro systems as well as to examine their chemical composition.

MATERIALS AND METHODS

Antioxidant activities of the extracts, subfractions and agrimoniin were evaluated using DPPH and three other radicals (O2(-), H2O2, and HClO) generated in cell-free systems. Anti-hyaluronidase activity was measured by using the turbidimetric method. Inhibition of lipoxidase activity was measured spectrophotometrically, using linoleic acid as a substrate. The composition of the most active subfraction was determined using the HPLC-DAD-MS(n) method.

RESULTS

All tested samples showed scavenging activity against all the examined reactive species in a concentration-dependent manner. The highest scavenging activity against DPPH, H2O2 and HClO was observed in the ethyl acetate subfraction (PRE3) (SC50 ± SEM [μg/mL]: 25.39 ± 2.49, 1.79 ± 0.25 and 8.52 ± 1.16 respectively). It was only in the xanthine/xanthine oxidase system that the antioxidation potential of the diethyl ether subfraction (PRE2) (SC50 ± SEM [μg/mL]: 6.59 ± 1.33) was higher than that of the subfraction PRE3 (SC50 ± SEM [μg/mL]: 8.57 ± 1.37). Also, in the studies of lipoxidase and hyaluronidase inhibition activity the strongest effect was observed for PRE3, with IC50 [μg/mL] = 86.31 ± 5.46, and 12.99 ± 1.31, respectively. The chromatographic method (HPTLC-DPPH) revealed that the principal substance responsible for the activity, is a tannin like compound. Isolated agrimoniin showed significant reactive oxygen species scavenging activity and significant enzyme inhibition activity (including xanthine oxidase inhibition activity). Agrimoniin exerted the strongest scavenging activity against H2O2 (SC50 ± SEM [μM]: 0.20 ± 0.01). This compound also significantly inhibited the enzymatic activity of lipoxidase (IC50 [μM] = 36.47 ± 1.29), and, particularly, of hyaluronidase (IC50 [μM] = 2.65 ± 0.40).

CONCLUSIONS

The strong scavenging activity against H2O2, and the inhibition of the enzymatic activity of lipoxidase, and particularly, hyaluronidase observed for the tested subfractions and agrimoniin, partly explain the beneficial effects of P. recta in treatment of skin inflammation.

C-glucosidic ellagitannins from Lythri herba (European Pharmacopoeia): chromatographic profile and structure determination

INTRODUCTION

Lythri herba, a pharmacopoeial plant material (European Pharmacopoea), is obtained from flowering parts of purple loosestrife (Lythrum salicaria L.). Although extracts from this plant material have been proven to possess some interesting biological activities and its pharmacopoeial standardisation is based on total tannin content determination, the phytochemical characterisation of this main group of compounds has not yet been fully conducted.

OBJECTIVE

To isolate ellagitannins from Lythri herba, determine their structures and develop chromatographic methods for their qualitative analysis.

RESULTS

Five C-glucosidic ellagitannins - monomeric- vescalagin and castalagin together with new dimeric structures - salicarinins A-C, composed of vescalagin and stachyurin, vescalagin and casuarinin, castalagin and casuarinin units connected via formation of valoneoyl group, were isolated using column chromatography and preparative HPLC. Structures were determined according to (1) H and (13) C-NMR (one- and two-dimensional), electrospray ionisation-time of flight (ESI-TOF), electrospray ionisation-ion trap (ESI-MS(n) ) and circular dichroism (CD) spectra, together with acidic hydrolysis products analysis. HPTLC on RP-18 modified plates and HPLC-DAD-MS(n) on RP-18 column methods were developed for separation of the five main ellagitannins.