Hamamelitannin from witch hazel (Hamamelis virginiana) displays specific cytotoxic activity against colon cancer cells

Polymodal K+ channel modulation contributes to dual analgesic and anti-inflammatory actions of traditional botanical medicines

Pain and inflammation contribute immeasurably to reduced quality of life, yet modern analgesic and anti-inflammatory therapeutics can cause dependence and side effects. Here, we screened 1444 plant extracts, prepared primarily from native species in California and the United States Virgin Islands, against two voltage-gated K+ channels - T-cell expressed Kv1.3 and nociceptive-neuron expressed Kv7.2/7.3. A subset of extracts both inhibits Kv1.3 and activates Kv7.2/7.3 at hyperpolarized potentials, effects predicted to be anti-inflammatory and analgesic, respectively. Among the top dual hits are witch hazel and fireweed; polymodal modulation of multiple K+ channel types by hydrolysable tannins contributes to their dual anti-inflammatory, analgesic actions. In silico docking and mutagenesis data suggest pore-proximal extracellular linker sequence divergence underlies opposite effects of hydrolysable tannins on different Kv1 isoforms. The findings provide molecular insights into the enduring, widespread medicinal use of witch hazel and fireweed and demonstrate a screening strategy for discovering dual anti-inflammatory, analgesic small molecules.

Hamamelis virginiana L. extract presents antimicrobial and antibiofilm effects, absence of cytotoxicity, anti-inflammatory action, and potential to fight infections through the nitric oxide production by macrophages

The potential of H. virginiana L. was evaluated against Candida spp. (C. albicans, C. dubliniensis, C. glabrata, C. guilliermondii, C. krusei, and C. tropicalis) and bacteria (Acinetobacter baumannii, Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, Staphylococcus aureus, and Streptococcus mutans). Effect on murine macrophages (RAW 264.7) was also evaluated with respect to cytotoxicity and production of cytokines (IL-1β and TNF-α) and nitric oxide (NO). The most effective concentrations of the extract were determined by microdilution broth. These concentrations were analyzed on biofilms, after 5 min or 24 h exposure. Cytotoxicity was performed by MTT assay and quantification of cytokines and NO by ELISA and Griess reagent, respectively. The extract acted against the planktonic forms and provided significant reductions of all the microbial biofilms; besides, showed no cytotoxic effect, except at 100 mg/mL, after 24 h exposure. There was cytokine production; however, a modulatory effect was observed in groups exposed to lipopolysaccharide (LPS) from E. coli. NO production was similar or higher than the control group. Thus, H. virginiana L. extract showed antimicrobial and antibiofilm effects; absence of cytotoxicity for RAW 264.7; anti-inflammatory action; and potential to fight infections through the NO production.

Dextran-Sulfate-Sodium-Induced Colitis-Ameliorating Effect of Aqueous Phyllanthus emblica L. Extract through Regulating Colonic Cell Gene Expression and Gut Microbiomes

The anti-inflammation effect of aqueous Phyllanthus emblica L. extract (APE) and its possible underlying mechanism in dextran sulfate sodium (DSS)-induced mice chronic colonic inflammation were studied. APE treatment significantly improved the colitic symptoms, including ameliorating the shortening of the colon, increasing the DSS-induced body weight loss, reducing the disease activity index, and reversing the condition of colon tissue damage of mucus lost and goblet cell reduction. Overproduction of serum pro-inflammatory cytokines were suppressed by the treatment of APE. Gut microbiome analysis showed that APE remodeled the structure of gut bacteria in phylum and genus levels, upregulating the abundance of phylum Bacteroidetes, family Muribaculaceae, and genus Bacteroides and downregulating the abundance of phylum Firmicutes. The reshaped gut microbiome caused metabolic functions and pathway change with enhanced queuosine biosynthesis and reduced polyamine synthesis pathway. Colon tissue transcriptome analysis further elucidated APE-inhibited mitogen-activated protein kinase (MAPK), cytokine-cytokine receptor interaction, and tumor necrosis factor (TNF) signaling pathways and the expressions of the genes that promote the progress of colorectal cancer. It turned out that APE reshaped the gut microbiome and inhibited MAPK, cytokine-cytokine receptor interaction, and TNF signaling pathways as well as the colorectal-cancer-related genes to exert its colitis protective effect.

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.

Evaluation of a Witch Hazel Extract for the Potential Prebiotic and Protective Effect on Select Lactiplantibacillus plantarum (Prev. Lactobacillus plantarum) Strains

Witch hazel extract has been evaluated in prior studies demonstrating the phenolic-mediated biofilm inhibition, toxin production inhibition, and growth inhibition in Staphylococcus aureus. In this study, we are evaluating the possible prebiotic and protective effect of witch hazel extract on select probiotic Lactiplantibacillus plantarum strains, namely L. plantarum LP 10241 and L. plantarum LPBAA-793. When the prebiotic effect was evaluated, we observed that the tested extract had prebiotic effect at the higher tested dose (0.5%) on LPBAA-793 strain (8.7 log CFU/mL after 18 h compared to 5.1 log CFU/mL with the control) and on LP 10241 strain (7.7 log CFU/mL after 18 h compared to 4.4 log CFU/mL with the control). For the evaluation of the protective effect of witch hazel extract on the select strains, we subjected nutrient depletion stress under aerobic conditions and monitored the cell death with and without addition of witch hazel extract. We observed that the tested extract had a significant protective effect on LPBAA-793 strain (4 log CFU/mL after 12 days, compared to no growth with control) and a slighter protective effect against LP 10241 strains (6.3 log CFU/mL in day 2 compared to 4.3 log CFU/mL with control). The results from this research provide for the first time the rationale that while witch hazel extract has significant antimicrobial, anti-toxin production and anti-biofilm activities on pathogenic microorganisms, it might play an important and positive role on health-beneficial probiotic bacteria.

Human Metabolites of Hamaforton™ (Hamamelis virginiana L. Extract) Modulates Fibroblast Extracellular Matrix Components in Response to UV-A Irradiation

Hamamelis virginiana L. a rich source of both condensed and hydrolyzable tannins, utilized to treat dermatological disorders. Since no experimental and clinical data is available for its use as oral formulation in skin related disorders, the purpose of this study was to investigate the effects of Hamaforton™ (Hamamelis virginiana extract) metabolites on gene dysregulation induced by ultraviolet A radiation in cultured human dermal fibroblasts. A combination of in vivo and ex vivo experimental designs has been exploited in order to take into account the polyphenol metabolic transformation that occurs in humans. 12 healthy volunteers received either a capsule of Hamaforton™ or a placebo in a randomized, blinded crossover trial. After Hamaforton™ ingestion, the kinetic of appearance of galloyl derivatives was measured in plasma. Then, in the ex vivo experiment, the serum isolated after supplementation was used as a source of Hamaforton™ metabolites to enrich the culture medium of dermal fibroblasts exposed to ultraviolet A radiation. Three different gallic acid metabolites (4-O-methyl gallic acid, 4-O-methyl gallic acid sulphate and trimethyl gallic acid glucuronide) were identified in volunteer plasma. While, ultraviolet A irradiation of dermal fibroblasts affected the expression of extracellular matrix genes, the presence of Hamaforton™ metabolites in the culture media did not affect the expression of most of those genes. However, the activation of the expression of 10 different genes involved in repair processes for the maintenance of skin integrity, suggest that the metabolites can play a role in damage recovery. To our knowledge, this is the first study that demonstrates the bioavailability of Hamaforton™ phenolic compounds, and the effects of its metabolites on cultured dermal fibroblast response to ultraviolet A irradiation.

An assessment of the growth inhibition profiles of Hamamelis virginiana L. extracts against Streptococcus and Staphylococcus spp

Staphylococcal and streptococcal species trigger a wide variety of infections involving epithelial tissues. Virginian witch hazel (WH; Hamamelis virginiana L.; family: Hamamelidaceae) is a plant that has been used traditionally by Native Americans to treat a variety of skin conditions. Extracts from the leaves were examined for their inhibitory effects on these bacterial species. Solvents of different polarity (water, methanol, ethyl acetate, hexane and chloroform) were used to prepare extracts from WH leaves, and the aqueous resuspensions were screened for antibacterial activities using disc diffusion and liquid dilution assays. Extract phytochemical profiles and toxicities were also examined, and combinations of extracts with conventional antibiotics were tested against each bacterial strain. The methanolic and aqueous extracts inhibited the growth of S. oralis, S. pyogenes, S. epidermidis and S. aureus, but not S. mutans. The extracts were especially active against staphylococcal species, with MIC values between 200 and 500 μg/ml. Combinations of active extracts with conventional antibiotics failed to yield beneficial interactions, except for two cases where additive interactions were observed (aqueous WH extract combined with chloramphenicol against S. oralis, and methanolic WH extract combined with ciprofloxacin against S. aureus). Phytochemical assays indicated an abundance of tannins, triterpenoids and phenolics in the water and methanol extracts, with trace amounts of these components in the ethyl acetate extract. Phytochemicals were not detected in hexane and chloroform extracts. Thus, phytochemical abundance in extracts was concordant with antibacterial activities. All extracts were found to be non-toxic in Artemia nauplii assays. These findings indicate the potential for WH leaf extracts for clinical use in treating staphylococcal and streptococcal infections, while substantiating their traditional Native American uses.

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H. virginiana extracts inhibited the growth of common bacterial skin pathogens.

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MIC values were determined and indicated strong inhibitory activity.

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The aqueous extract potentiated the antibacterial activity of chloramphenicol.

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The methanolic extracts potentiated activity of ciprofloxacin.

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All extracts were determined to be non-toxic by Artemia nauplii assays.

New Unnatural Gallotannins: A Way toward Green Antioxidants, Antimicrobials and Antibiofilm Agents

Nature has been a source of inspiration for the development of new pharmaceutically active agents. A series of new unnatural gallotannins (GTs), derived from d-lyxose, d-ribose, l-rhamnose, d-mannose, and d-fructose have been designed and synthesized in order to study the protective and antimicrobial effects of synthetic polyphenols that are structurally related to plant-derived products. The structures of the new compounds were confirmed by various spectroscopic methods. Apart from spectral analysis, the antioxidant activity was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging and iron reducing power (FRAP) assays. Antibacterial activity of compounds was tested in vitro against Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212 (reference and control strains), three methicillin-resistant isolates of S. aureus, and three isolates of vancomycin-resistant E. faecalis. For screening of antimycobacterial effect, a virulent isolate of Mycobacterium tuberculosis and two non-tuberculous mycobacteria were used. Furthermore, antibiofilm activity of structurally different GTs against S. aureus, and their ability to inhibit sortase A, were inspected. Experimental data revealed that the studied GTs are excellent antioxidants and radical-scavenging agents. The compounds exhibited only a moderate antibacterial effect against Gram-positive pathogens S. aureus and E. faecalis and were practically inactive against mycobacteria. However, they were efficient inhibitors and disruptors of S. aureus biofilms in sub-MIC concentrations, and interacted with the quorum-sensing system in Chromobacteriumviolaceum. Overall, these findings suggest that synthetic GTs could be considered as promising candidates for pharmacological, biomedical, consumer products, and for food industry applications.

The Microbiome of the Medicinal Plants Achillea millefolium L. and Hamamelis virginiana L

In the recent past many studies investigated the microbiome of plants including several medicinal plants (MP). Microbial communities of the associated soil, rhizosphere and the above-ground organs were included, but there is still limited information on their seasonal development, and in particular simultaneous investigations of different plant organs are lacking. Many studies predominantly addressed either the prokaryotic or fungal microbiome. A distinction of epi- and endophytic communities of above-ground plant organs has rarely been made. Therefore, we conducted a comprehensive investigation of the bacterial and fungal microbiome of the MP Achillea millefolium and studied the epi- and endophytic microbial communities of leaves, flower buds and flowers between spring and summer together with the microbiome of the associated soil at one location. Further, we assessed the core microbiome of Achillea from four different locations at distances up to 250 km in southern Germany and Switzerland. In addition, the bacterial and fungal epi- and endophytic leaf microbiome of the arborescent shrub Hamamelis virginiana and the associated soil was investigated at one location. The results show a generally decreasing diversity of both microbial communities from soil to flower of Achillea. The diversity of the bacterial and fungal endophytic leaf communities of Achillea increased from April to July, whereas that of the epiphytic leaf communities decreased. In contrast, the diversity of the fungal communities of both leaf compartments and that of epiphytic bacteria of Hamamelis increased over time indicating plant-specific differences in the temporal development of microbial communities. Both MPs exhibited distinct microbial communities with plant-specific but also common taxa. The core taxa of Achillea constituted a lower fraction of the total number of taxa than of the total abundance of taxa. The results of our study provide a basis to link interactions of the microbiome with their host plant in relation to the production of bioactive compounds.

Drug Screening of Potential Multiple Target Inhibitors for Estrogen Receptor-α-positive Breast Cancer

BACKGROUND/AIM

Estrogen receptor α (ERα) antagonist is the most common treatment for ERα-positive breast cancer. However, compensatory signaling contributes to resistance to ERα antagonists. Thus, to explore the potential agents for targeting compensatory signaling, we screened multiple target inhibitors for breast cancer treatment.

MATERIALS AND METHODS

We attempted to build a structure-based virtual screening model that can find potential compounds and assay the anticancer ability of these drugs by overall cell survival assay. The downstream compensatory phosphorylated signaling was measured by immunoblotting.

RESULTS

Hamamelitannin and glucocheirolin were hits for ERα, phosphoinositide 3-kinase (PI3K), and KRAS proto-oncogene, GTPase (KRAS), which were active against estrogen and epidermal growth factor-triggered proliferation. Additionally, we select aminopterin as a hit for ERα, PI3K, KRAS, and SRC proto-oncogene, non-receptor tyrosine kinase (SRC) with inhibitory activities toward AKT serine/threonine kinase 1 (AKT) and mitogen-activated protein kinase kinase (MEK) signaling.

CONCLUSION

Our structure-based virtual screening model selected hamamelitannin, glucocheirolin, aminopterin, and pemetrexed as compounds that may act as potential inhibitors for improving endocrine therapies for breast cancer.

Preliminary Identification of Hamamelitannin and Rosmarinic Acid as COVID-19 Inhibitors Based on Molecular Docking

Background:

Recently, novel coronavirus disease, COVID-19 caused the outbreak situation of global public health. In this pandemic situation, all the people's lives of 212 Countries and Territories have been affected due to partial or complete lockdown and also as a result of mandatory isolations or quarantines. This is due to the non-availability of any secure vaccine.

Objective:

The present study helps us to identify and screen the best phytochemicals as potent inhibitors against COVID-19.

Methods:

In this paper, we choose two standard drugs namely hamamelitannin and rosmarinic acid as a probable inhibitor of pandemic COVID-19 receptor as compared to antimalarial drugs hydroxychloroquine, anti-viral drug remdesivir, and also baricitinib. This study was done by taking into consideration of molecular docking study, performed with Auto Dock 4.0 (AD4.0). All chemical structures were optimized with the Avogadro suite by applying the MMFF94 force field and also hamamelitannin, rosmarinic acid was optimized using the Gaussian G16 suite of UB3LYP/6- 311++G(d,p) basis set. Protein-ligand interaction was visualized by PyMOL software.

Results:

This work has provided an insightful understanding of protein-ligand interaction of hamamelitannin and rosmarinic acid showing comparable binding energies than that of clinically applying probable COVID-19 inhibitors hydroxychloroquine (an anti-malarial drug) and remdesivir (an anti-viral drug).

Conclusions:

We will expect that if its anti-SARS-CoV-2 activity is validated in human clinical trials, these two drugs may be developed as an effective antiviral therapeutics towards infected patients in this outbreak and pandemic situation of COVID-19.

Natural products as inspiration for the development of bacterial antibiofilm agents

Natural products have historically been a rich source of diverse chemical matter with numerous biological activities, and have played an important role in drug discovery in many areas including infectious disease. Synthetic and medicinal chemistry have been, and continue to be, important tools to realize the potential of natural products as therapeutics and as chemical probes. The formation of biofilms by bacteria in an infection setting is a significant factor in the recalcitrance of many bacterial infections, conferring increased tolerance to many antibiotics and to the host immune response, and as yet there are no approved therapeutics for combatting biofilm-based bacterial infections. Small molecules that interfere with the ability of bacteria to form and maintain biofilms can overcome antibiotic tolerance conferred by the biofilm phenotype, and have the potential to form combination therapies with conventional antibiotics. Many natural products with anti-biofilm activity have been identified from plants, microbes, and marine life, including: elligic acid glycosides, hamamelitannin, carolacton, skyllamycins, promysalin, phenazines, bromoageliferin, flustramine C, meridianin D, and brominated furanones. Total synthesis and medicinal chemistry programs have facilitated structure confirmation, identification of critical structural motifs, better understanding of mechanistic pathways, and the development of more potent, more accessible, or more pharmacologically favorable derivatives of anti-biofilm natural products.

Molecular process of glucose uptake and glycogen storage due to hamamelitannin via insulin signalling cascade in glucose metabolism

Understanding the mechanism by which the exogenous biomolecule modulates the GLUT-4 signalling cascade along with the information on glucose metabolism is essential for finding solutions to increasing cases of diabetes and metabolic disease. This study aimed at investigating the effect of hamamelitannin on glycogen synthesis in an insulin resistance model using L6 myotubes. Glucose uptake was determined using 2-deoxy-D-[1-³H] glucose and glycogen synthesis were also estimated in L6 myotubes. The expression levels of key genes and proteins involved in the insulin-signaling pathway were determined using real-time PCR and western blot techniques. The cells treated with various concentrations of hamamelitannin (20 µM to 100 µM) for 24 h showed that, the exposure of hamamelitannin was not cytotoxic to L6 myotubes. Further the 2-deoxy-D-[1-³H] glucose uptake assay was carried out in the presence of wortmannin and Genistein inhibitor for studying the GLUT-4 dependent cell surface recruitment. Hamamelitannin exhibited anti-diabetic activity by displaying a significant increase in glucose uptake (125.1%) and glycogen storage (8.7 mM) in a dose-dependent manner. The optimum concentration evincing maximum activity was found to be 100 µm. In addition, the expression of key genes and proteins involved in the insulin signaling pathway was studied to be upregulated by hamamelitannin treatment. Western blot analysis confirmed the translocation of GLUT-4 protein from an intracellular pool to the plasma membrane. Therefore, it can be conceived that hamamelitannin exhibited an insulinomimetic effect by enhancing the glucose uptake and its further conversion into glycogen by regulating glucose metabolism.

Evaluation of the genotoxic, DNA-protective and antioxidant profile of synthetic alkyl gallates and gallotannins using in vitro assays

New gallotanins, methyl 2,3,4,6-tetra-O-galloyl-α-D-glucoside (G₄Glc), methyl 2,3,4,6-tetra-O-galloyl-α-D-mannoside (G₄Man), and methyl 2,3,4-tri-O-galloyl-α-L-rhamnoside (G₃Rham), have been synthesized in order to study the protective effects of synthetic polyphenols that are structurally related with natural compounds. Apart from spectral analysis, examination of antioxidant ability and protective efficiency showed the differences among newly prepared compounds and commercial antioxidants - gallic acid (GA), methyl gallate (MG), and octyl gallate (OG) applying radical scavenging 1,1-diphenyl-2-picryl-hydrazyl (DPPH), reducing power and iron-chelating assays. The genotoxicity and DNA-protective potential of tested compounds on human peripheral blood mononuclear cells (PBMCs) were evaluated using the single-cell gel electrophoresis (comet assay) and DNA-topology assay. Experimental data revealed that gallotannins G₃Rham, G₄Man, and G₄Glc possess significant radical scavenging/antioxidant activities and manifest very low genotoxic effect on human PBMCs. Moreover, tested compounds considerably reduce the level of DNA damage induced by hydrogen peroxide or Fe²⁺-ions. The results imply that new synthetic gallotannins can be considered as nontoxic agents for subsequent design of new antioxidants with potential biomedical applications.

Witch Hazel Significantly Improves the Efficacy of Commercially Available Teat Dips

Bovine intramammary infections (IMIs) are the main cause of economic loss in milk production. Antibiotics are often ineffective in treating infections due to antimicrobial resistance and the formation of bacterial biofilms that enhance bacterial survival and persistence. Teat dips containing germicides are recommended to prevent new IMIs and improve udder health and milk quality. IMIs are often caused by staphylococci, which are Gram-positive bacteria that become pathogenic by forming biofilms and producing toxins. As a model for a teat dip (DIP), the BacStop iodine-based teat dip (DIP) was used. Witch hazel extract (whISOBAX (WH)) was tested because it contains a high concentration of the anti-biofilm/anti-toxin phenolic compound hamamelitannin. We found that the minimal inhibitory or bactericidal concentrations of DIP against planktonic S. epidermidis cells increased up to 160fold in the presence of WH, and that DIP was 10-fold less effective against biofilm cells. While both DIP and WH are effective in inhibiting the growth of S. aureus, only WH inhibits toxin production (tested for enterotoxin-A). Importantly, WH also significantly enhances the antibacterial effect of DIP against Gram-negative bacteria that can cause IMIs, like Escherichia coli and Pseudomonas aeruginosa. Put together, these results suggest that the antibacterial activity of DIP combined with WH is significantly higher, and thus have potential in eradicating bacterial infections, both in acute (planktonic-associated) and in chronic (biofilm-associated) conditions.

The Phytochemistry of Cherokee Aromatic Medicinal Plants

Background: Native Americans have had a rich ethnobotanical heritage for treating diseases, ailments, and injuries. Cherokee traditional medicine has provided numerous aromatic and medicinal plants that not only were used by the Cherokee people, but were also adopted for use by European settlers in North America. Methods: The aim of this review was to examine the Cherokee ethnobotanical literature and the published phytochemical investigations on Cherokee medicinal plants and to correlate phytochemical constituents with traditional uses and biological activities. Results: Several Cherokee medicinal plants are still in use today as herbal medicines, including, for example, yarrow (Achillea millefolium), black cohosh (Cimicifuga racemosa), American ginseng (Panax quinquefolius), and blue skullcap (Scutellaria lateriflora). This review presents a summary of the traditional uses, phytochemical constituents, and biological activities of Cherokee aromatic and medicinal plants. Conclusions: The list is not complete, however, as there is still much work needed in phytochemical investigation and pharmacological evaluation of many traditional herbal medicines.

HPLC Analysis, Optimization of Extraction Conditions and Biological Evaluation of Corylopsis coreana Uyeki Flos

A method for the separation and quantification of three flavonoids and one isocoumarin by reverse-phase high performance liquid chromatography (HPLC) has been developed and validated. Four constituents present in a crude ethanolic extract of the flowers of Coryloposis coreana Uyeki, were analyzed. Bergenin, quercetin, quercitrin and isosalipurposide were used as calibration standards. In the present study, an excellent linearity was obtained with an r² higher than 0.999. The chromatographic peaks showed good resolution. In combination with other validation data, including precision, specificity, and accuracy, this method demonstrated good reliability and sensitivity, and can be conveniently used for the quantification of bergenin, quercetin, quercitrin and isosalipurposide in the crude ethanolic extract of C. coreana Uyeki flos. Furthermore, the plant extracts were analyzed with HPLC to determine the four constituents and compositional differences in the extracts obtained under different extraction conditions. Several extracts of them which was dependent on the ethanol percentage of solvent were also analyzed for their antimicrobial and antioxidant activities. One hundred % ethanolic extract from C. coreana Uyeki flos showed the best antimicrobial activity against the methicillin-resistant Staphylococcus aureus (MRSA) strain. Eighty % ethanolic extract showed the best antioxidant activity and phenolic content. Taken of all, these results suggest that the flower of C. coreana Uyeki flos may be a useful source for the cure and/or prevention of septic arthritis, and the validated method was useful for the quality control of C. coreana Uyeki.

Tannins from Hamamelis virginiana bark extract: characterization and improvement of the antiviral efficacy against influenza A virus and human papillomavirus

Antiviral activity has been demonstrated for different tannin-rich plant extracts. Since tannins of different classes and molecular weights are often found together in plant extracts and may differ in their antiviral activity, we have compared the effect against influenza A virus (IAV) of Hamamelis virginiana L. bark extract, fractions enriched in tannins of different molecular weights and individual tannins of defined structures, including pseudotannins. We demonstrate antiviral activity of the bark extract against different IAV strains, including the recently emerged H7N9, and show for the first time that a tannin-rich extract inhibits human papillomavirus (HPV) type 16 infection. As the best performing antiviral candidate, we identified a highly potent fraction against both IAV and HPV, enriched in high molecular weight condensed tannins by ultrafiltration, a simple, reproducible and easily upscalable method. This ultrafiltration concentrate and the bark extract inhibited early and, to a minor extent, later steps in the IAV life cycle and tannin-dependently inhibited HPV attachment. We observed interesting mechanistic differences between tannin structures: High molecular weight tannin containing extracts and tannic acid (1702 g/mol) inhibited both IAV receptor binding and neuraminidase activity. In contrast, low molecular weight compounds (<500 g/mol) such as gallic acid, epigallocatechin gallate or hamamelitannin inhibited neuraminidase but not hemagglutination. Average molecular weight of the compounds seemed to positively correlate with receptor binding (but not neuraminidase) inhibition. In general, neuraminidase inhibition seemed to contribute little to the antiviral activity. Importantly, antiviral use of the ultrafiltration fraction enriched in high molecular weight condensed tannins and, to a lesser extent, the unfractionated bark extract was preferable over individual isolated compounds. These results are of interest for developing and improving plant-based antivirals.

Green tea phenolics inhibit butyrate-induced differentiation of colon cancer cells by interacting with monocarboxylate transporter 1

Diet has a significant impact on colorectal cancer and both dietary fiber and plant-derived compounds have been independently shown to be inversely related to colon cancer risk. Butyrate (NaB), one of the principal products of dietary fiber fermentation, induces differentiation of colon cancer cell lines by inhibiting histone deacetylases (HDACs). On the other hand, (-)-epicatechin (EC) and (-)-epigallocatechin gallate (EGCG), two abundant phenolic compounds of green tea, have been shown to exhibit antitumoral properties. In this study we used colon cancer cell lines to study the cellular and molecular events that take place during co-treatment with NaB, EC and EGCG. We found that (i) polyphenols EC and EGCG fail to induce differentiation of colon adenocarcinoma cell lines; (ii) polyphenols EC and EGCG reduce NaB-induced differentiation; (iii) the effect of the polyphenols is specific for NaB, since differentiation induced by other agents, such as trichostatin A (TSA), was unaltered upon EC and EGCG treatment, and (iv) is independent of the HDAC inhibitory activity of NaB. Also, (v) polyphenols partially reduce cellular NaB; and (vi) on a molecular level, reduction of cellular NaB uptake by polyphenols is achieved by impairing the capacity of NaB to relocalize its own transporter (monocarboxylate transporter 1, MCT1) in the plasma membrane. Our findings suggest that beneficial effects of NaB on colorectal cancer may be reduced by green tea phenolic supplementation. This valuable information should be of assistance in choosing a rational design for more effective diet-driven therapeutic interventions in the prevention or treatment of colorectal cancer.

Polyphenols from the bark of Rhus verniciflua and their biological evaluation on antitumor and anti-inflammatory activities

Bioassay-guided fractionation and chemical investigation of the extract of Rhus verniciflua bark resulted in the identification of six polyphenols, rhusopolyphenols A-F (1-6), together with four known compounds including (2R,3S,10S)-7,8,9,13-tetrahydroxy-2-(3,4-dihydroxyphenyl)-2,3-trans-3,4-cis-2,3,10-trihydrobenzopyrano[3,4-c]-2-benzopyran-1-one (7), peapolyphenol C (8), cilicione-b (9) and (αR)-α,3,4,2',4'-pentahydroxydihydrochalcone (10). The structures of these polyphenols were elucidated by spectroscopic analysis, including 1D and 2D NMR, and HR-ESIMS, and their absolute configurations were further confirmed by a combination of chemical methods and CD data analysis. All isolates were evaluated for their antiproliferative activities against four human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT-15), and compounds 4-6, 9 and 10 showed antiproliferative activity against the tested cells, with IC50 values of 3.31-18.51 μM. On the basis of the expanded understanding that inflammation is a crucial cause of tumor progression, the anti-inflammatory activities of these compounds were determined by measuring nitric oxide (NO) levels in the medium of murine microglia BV-2 cells. Compounds 5 and 10 significantly inhibited NO production in lipopolysaccharide (LPS)-stimulated murine microglia BV-2 cells with IC50 values of 28.90 and 12.70 μM, respectively.

Epicatechin gallate impairs colon cancer cell metabolic productivity

Green tea and grape phenolics inhibit cancer growth and modulate cellular metabolism. Targeting the tumor metabolic profile is a novel therapeutic approach to inhibit cancer cell proliferation. Therefore, we treated human colon adenocarcinoma HT29 cells with the phenolic compound epicatechin gallate (ECG), one of the main catechins in green tea and the most important catechin in grape extracts, and evaluated its antiproliferation effects. ECG reduced tumor viability and induced apoptosis, necrosis, and S phase arrest in HT29 cells. Later, biochemical determinations combined with mass isotopomer distribution analysis using [1,2-(13)C2]-D-glucose as a tracer were used to characterize the metabolic network of HT29 cells in response to different concentrations of ECG. Glucose consumption was importantly decreased after ECG treatment. Moreover, metabolization of [1,2-(13)C2]-D-glucose indicated that the de novo synthesis of fatty acids and the pentose phosphate pathway were reduced in ECG-treated cells. Interestingly, ECG inhibited the activity of transketolase and glucose-6-phosphate dehydrogenase, the key enzymes of the pentose phosphate pathway. Our data point to ECG as a promising chemotherapeutic agent for the treatment of colon cancer.

High-Throughput Screening to Identify Plant Derived Human LDH-A Inhibitors

Aims

Lactate dehydrogenase (LDH)-A is highly expressed in diverse human malignant tumors, parallel to aggressive metastatic disease, resistance to radiation/chemotherapy and clinically poor outcome. Although this enzyme constitutes a plausible target in treatment of advanced cancer, there are few known LDH-A inhibitors.

Study Design

In this work, we utilized a high-throughput enzyme micro-array format to screen and evaluate > 900 commonly used medicinal plant extracts (0.00001-.5 mg/ml) for capacity to inhibit activity of recombinant full length human LDHA; EC .1.1.1.27.

Methodology

The protein sequence of purified enzyme was confirmed using 1D gel electrophoresis- MALDI-TOF-MS/MS, enzyme activity was validated by oxidation of NADH (500μM) and kinetic inhibition established in the presence of a known inhibitor (Oxalic Acid).

Results

Of the natural extracts tested, the lowest IC₅₀s [<0.001 mg/ml] were obtained by: Chinese Gallnut (Melaphis chinensis gallnut), Bladderwrack (Fucus vesiculosus), Kelp (Laminaria Japonica) and Babul (Acacia Arabica). Forty-six additional herbs contained significant LDH-A inhibitory properties with IC₅₀s [<0.07 mg/ml], some of which have common names of Arjun, Pipsissewa, Cinnamon, Pink Rose Buds/Petals, Wintergreen, Cat’s Claw, Witch Hazel Root and Rhodiola Root.

Conclusion

These findings reflect relative potency by rank of commonly used herbs and plants that contain human LDH-A inhibitory properties. Future research will be required to isolate chemical constituents within these plants responsible for LDH-A inhibition and investigate potential therapeutic application.