α-Glucosidase inhibitory effect by the flower buds of Tussilago farfara L

Multispectroscopic and Computational Investigations on the Binding Mechanism of Dicaffeoylquinic Acids with Ovalbumin

Recently, studies on the interactions between ovalbumin (OVA) and polyphenols have received a great deal of interest. This study explored the conformational changes and the interaction mechanism of the binding between OVA and chlorogenic acid (CGA) isomers such as 3,4-dicaffeoylquinic acids (3,4-diCQA), 4,5-dicaffeoylquinic acids (4,5-diCQA), and 3,5-dicaffeoylquinic acids (3,5-diCQA) using multispectroscopic and in silico analyses. The emission spectra show that the diCQAs caused strong quenching of OVA fluorescence under different temperatures through a static quenching mechanism with hydrogen bond (H-bond) and van der Waals (vdW) interactions. The values of binding constants (OVA-3,4-diCQA = 6.123 × 10⁵, OVA-3,5-diCQA = 2.485 × 10⁵, OVA-4,5-diCQA = 4.698 × 10⁵ dm³ mol^-1 at 298 K) suggested that diCQAs had a strong binding affinity toward OVA, among which OVA-3,4-diCQA exhibits higher binding constant. The results of UV-vis absorption and synchronous fluorescence indicated that the binding of all three diCQAs to OVA induced conformational and micro-environmental changes in the protein. The findings of molecular modeling further validate the significant role of vdW force and H-bond interactions in ensuring the stable binding of OVA-diCQA complexes. Temperature-dependent molecular dynamics simulation studies allow estimation of the individual components that contribute to the total bound free energy value, which allows evaluation of the nature of the interactions involved. This research can provide information for future investigations on food proteins' physicochemical stability and CGA bioavailability in vitro or in vivo.

Definition of chemical markers for Hancornia speciosa Gomes by chemometric analysis based on the chemical composition of extracts, their vasorelaxant effect and α-glucosidase inhibition

ETHNOPHARMACOLOGICAL RELEVANCE

Hancornia speciosa Gomes (Apocynaceae) is a tree found in the Brazilian savannah, traditionally used to treat several diseases, including diabetes and hypertension. The anti-hypertensive activity of H. speciosa leaves (HSL) has been demonstrated in different models and is credited to the vasodilator effect and ACE (angiotensin-converting enzyme) inhibition. The hypoglycemic effect of HSL has been also reported.

AIM OF THE STUDY

To establish correlations between the biological activities elicited by H. speciosa extracts and the contents of their major compounds, aiming to define chemical markers related to the potential antihypertensive and antidiabetic effects of the species. Additionally, it aimed to isolate and characterize the chemical structure of a marker related to the α-glucosidase inhibitory effect.

MATERIALS AND METHODS

Extracts of a single batch of H. speciosa leaves were prepared by extraction with distinct solvents (ethanol/water in different proportions; methanol/ethyl acetate), employing percolation or static maceration as extraction techniques, at different time intervals. The contents of chlorogenic acid, rutin and FlavHS (a tri-O-glycoside of quercetin) were quantified by a developed and validated HPLC-PDA method. Bornesitol was determined by HPLC-PDA after derivatization with tosyl chloride, whereas total flavonoids were measured spectrophotometrically. Identification of other constituents in the extracts was performed by UPLC-DAD-ESI-MS/MS analysis. The vasorelaxant activity was assayed in rat aortic rings precontracted with phenylephrine, and α-glucosidase inhibition was tested in vitro. Principal component analysis (PCA) was employed to evaluate the contribution of each marker to the biological responses. Isolation of compound 1 was carried out by column chromatography and structure characterization was accomplished by NMR and UPLC-DAD-ESI-MS/MS analyses.

RESULTS

The contents of the chemical markers (mean ± s.d. % w/w) varied significantly among the extracts, including total flavonoids (2.68 ± 0.14 to 5.28 ± 0.29), bornesitol (5.11 ± 0.26 to 7.75 ± 0.78), rutin (1.46 ± 0.06 to 1.97 ± 0.02), FlavHS (0.72 ± 0.05 to 0.94 ± 0.14) and chlorogenic acid (0.67 ± 0.09 to 0.91 ± 0.02). All extracts elicited vasorelaxant effect (pIC₅₀ between 4.97 ± 0.22 to 6.48 ± 0.10) and α-glucosidase inhibition (pIC₅₀ between 3.49 ± 0.21 to 4.03 ± 0.10). PCA disclosed positive correlations between the vasorelaxant effect and the contents of chlorogenic acid, rutin, total flavonoids, and FlavHS, whereas a negative correlation was found with bornesitol concentration. No significant correlation between α-glucosidase inhibition and the contents of the above-mentioned compounds was found. On the other hand, PCA carried out with the areas of the ten major peaks from the chromatograms disclosed positive correlations between a peak ascribed to co-eluted triterpenes and α-glucosidase inhibition. A triterpene was isolated and identified as 3-O-β-(3'-R-hydroxy)-hexadecanoil-lupeol.

CONCLUSION

According to PCA results, the vasorelaxant activity of H. speciosa extracts is related to flavonoids and chlorogenic acid, whereas the α-glucosidase inhibition is associated with lipophilic compounds, including esters of lupeol like 3-O-β-(3'-R-hydroxy)-hexadecanoil-lupeol, described for the first time for the species. These compounds can be selected as chemical markers for the quality control of H. speciosa plant drug and derived extracts.

Evaluation of the Chemical Composition, Antioxidant and Antidiabetic Activity of Rhaponticoides iconiensis Flowers: Effects on Key Enzymes Linked to Type 2 Diabetes In Vitro, In Silico and on Alloxan-Induced Diabetic Rats In Vivo

Diabetes mellitus (DM) is one of the globally worst killer diseases. In this study, the in vitro and in vivo antidiabetic activity and antioxidant capacity were determined and the phytochemical analyses were carried out on flower extract and sub-extracts of Rhaponticoides iconiensis. The in vitro antidiabetic activity was tested with α-amylase and α-glucosidase enzyme inhibition methods and an in vivo OGTT test in healthy and alloxan-induced rats. Although, the antioxidant activity was investigated with DPPH●, ABTS●+ and FRAP tests, the phytochemical composition analysis was carried out by LC-MS/MS. The highest α-glucosidase and α-amylase activity even from positive control acarbose were found in the ethyl acetate sub-extract of R. iconiensis (IC50 = 11.737 ± 0.823 µg/mL and 84.247 ± 0.721 µg/mL, respectively). This sub-extract also was active according to the results of in vivo tests. Moreover, the highest antioxidant activity on DPPH● (IC50 = 0.126 ± 0.002 mg/mL), FRAP (at a concentration of 1 mg/mL equivalent to 3112.052 ± 2.023 mmol Fe2+) and ABTS+● (at a concentration of 0.5 mg/mL equivalent to 0.608 ± 0.005 µM Trolox) tests. In addition, LC-MS/MS analyses of the active sub-extract revealed mainly the presence of patuletin, patuletin 3,7-diglucoside, naringin and 3,4-dicaffeoylquinic acid detected in the active sub-extract. In silico molecular docking and dynamics simulations studies were performed on these compounds with α-amylase and α-glucosidase enzymes for protein-ligand interactions and stability.

Isolation and identification of Tussilago farfara leaf spot caused by Alternaria alternata in China

Tussilago farfara is of vital medical value. A new leaf spot disease was observed on T. farfara leaves, in Dingxi, Gansu Province, China, in October 2019. In order to research the pathogen, the diseased samples were collected for isolation and identification. The isolate KD3 was verified by pathogenicity test, as the pathogen causing the T. farfara leaf spot disease. Its morphological characteristics were consistent with Alternaria alternata, the colony color gray-green with concentric rings, conidia fusiform and pear-shaped, brown, with 1-7 septa and 0-3 longitudinal septa, conidia size (19. 62-44.49) μm × (6.97-10.53) μm, beak length (1.35-10.03) μm × (1.01-3.63) μm, and the spore phenotype was a dwarf tree-like chain of short conidia. Multilocus sequences analysis manifested that the internal transcribed spacer (ITS), Alternaria major allergen (Alta1), and Calcium barine (CAL) sequences of strain KD3 were most closely to A. alternata (A23), with the homology of 99.47%, 99.56% and 98.28%, respectively. Based on morphological and molecular characteristics, strain KD3 was identified as A. alternata. OA was the optimal medium for its growth and PCA medium was the optimal for sporulation. This is the first report of A. alternata causing T. farfara leaf spots in China.

Recent advances on discovery of enzyme inhibitors from natural products using bioactivity screening

The essence of enzymes is to keep the homeostasis and balance of human by catalyzing metabolic responses and modulating cell. Suppression of enzyme slows the progress of some diseases, making it a therapeutic target. Therefore, it is important to develop enzyme inhibitors by proper bioactivity screening strategies for the future treatment of some major diseases. In this review, we summarized the recent (2015-2020) applications of several screening strategies (electrophoretically mediated microanalysis, enzyme immobilization, affinity chromatography, and affinity ultrafiltration) in finding enzyme inhibitors from certain species of bioactive natural compounds of plant origin (flavonoids, alkaloids, phenolic acids, saponins, anthraquinones, coumarins). At the same time, the advantages and disadvantages of each strategy were also discussed, and the future possible development direction in enzyme inhibitor screening has prospected. To sum up, it is expected to help readers select suitable screening strategies for enzyme inhibitors and provide useful information for the study of the biological of specific kinds of natural products. This article is protected by copyright. All rights reserved.

Simultaneous Determination of Seven Phenolic Acids, Two Flavonoids, and Tussilagone in Rat Plasma after Administration of Farfarae Flos Extract by LC-MS/MS

A simple LC-MS/MS method was established for the simultaneous quantitative analysis of concentration of seven phenolic acids, two flavonoids, and tussilagone in biological samples. The lower limit of quantitation of each target compound was less than 10 ng·mL⁻¹. The precision of these three types of compounds was less than 15%, and all accuracy was between 85.9% and 115%. The preliminary pharmacokinetics of these three types of compounds in plasma samples were carried out using LC-MS/MS after administration of Farfarae Flos extract (3.90 and 7.80 g·kg⁻¹) to rats, respectively. The results showed that T_max of all ten compounds varied from 0.21 ± 0.04 h to 0.69 ± 0.19 h. Maximum concentrations and area under concentration-time curves of seven analyzed phenolic acids were higher than those of the two flavonoids and tussilagone. Terminal elimination half-life of tussilagone was the shortest among these three types of compounds. The results showed that the developed LC-MS/MS method was suitable for clarifying the pharmacokinetic characteristics of these three types of compounds in plasma after administration of Farfarae Flos extract in rats.

Ursane-type triterpene oligoglycosides with anti-hepatosteatosis and anti-hyperlipidemic activity from the leaves of Ilex paraguariensis A. St.-Hil

The methanol extract from the leaves of Ilex paraguariensis A. St.-Hil. (Aquifoliaceae), popularly known as mate, maté, or yerba maté, inhibits the intracellular triglyceride accumulation in HepG2 cells and suppresses the plasma triglyceride elevation in olive oil-treated mice. Three new triterpene saponins, termed mateosides I (1), II (2), and III (3), were isolated from the extract along with 29 known compounds. The structures of 1-3 were elucidated based on chemical and spectroscopic evidence. Among the isolates, principal saponin constituents, 2 and matesaponins 1 (7) and 2 (9), potently inhibited the triglyceride accumulation in HepG2 cells simultaneously treated with oleic acid and high glucose. In vivo assay of the methanol extract of I. paraguariensis revealed that 7 and 9 showed anti-hyperlipidemic activities in olive oil-treated mice. These results suggested that the saponin constituents of I. paraguariensis could be valuable bioactive marker for the anti-obesogenic activity.

Cooking and In Vitro Digestion Modulate the Anti-Diabetic Properties of Red-Skinned Onion and Dark Purple Eggplant Phenolic Compounds

The intake of phenolic-rich foods is an emerging preventive approach for the management of type 2 diabetes, thanks to the ability of these compounds to inhibit some key metabolic enzymes. In this study, the influence of cooking and in vitro digestion on the α-glucosidase, α-amylase, and dipeptidyl-peptidase IV (DPP-IV) inhibitory activity of red-skinned onion (RSO) and dark purple eggplant (DPE) phenolic fractions was assessed. The applied cooking procedures had different influences on the total and individual phenolic compounds gastrointestinal bioaccessibility. DPE in vitro digested phenolic fractions displayed no inhibitory activity versus α-amylase and DPP-IV, whereas the fried DPE sample exhibited moderate inhibitory activity against α-glucosidase. This sample mainly contained hydroxycinnamic acid amides that can be responsible for the observed effect. Contrariwise, raw and cooked in vitro digested RSO phenolic fractions inhibited all three enzymes but with different effectiveness. Fried and raw RSO samples were the most active against them. Statistical analysis pointed out that quercetin mono-hexosides (mainly quercetin-4′-O-hexoside) were responsible for the inhibition of α-glucosidase, whereas quercetin di-hexosides (mainly quercetin-3-O-hexoside-4′-O-hexoside) were responsible for the DPP-IV-inhibitory activity of RSO samples. An accurate design of the cooking methods could be essential to maximize the release of individual phenolic compounds and the related bioactivities.

The ethanol extract of flower buds of Tussilago farfara L. attenuates cigarette smoke-induced lung inflammation through regulating NLRP3 inflammasome, Nrf2, and NF-κB

ETHNOPHARMACOLOGICAL RELEVANCE

The flower buds of Tussilago farfara L. (Abbreviated as FTF) were widely used in traditional Chinese medicine (TCM) to treat respiratory diseases, including asthma, dry throat, great thirst, turbid saliva, stinky pus, and coughs caused by various causes.

AIM OF STUDY

The aim of study is to explore the efficiency of FTF in vitro and in vivo for the treatment of lung inflammation, and to illustrate the possible mechanisms of FTF in treating inflammation-related respiratory diseases targeting NOD-like receptor 3 (NLRP3) inflammasome, nuclear factor erythroid 2-related factor 2 (Nrf2), and nuclear transcription factor-κB (NF-κB).

METHODS

Lung inflammation model in vivo was induced by exposure of mice to cigarette smoke (CS) for two weeks. The levels of superoxide dismutase (SOD), malondialdehyde (MDA), inflammatory factors, and histology in lung tissues were investigated in presence or absence of ethanol extract of the flower buds of T. farfara L. (FTF-EtOH). In the cell-based models, nitric oxide (NO) assay, flow cytometry assay, enzyme-linked immunosorbent assay (Elisa), and glutathione (GSH) assay were used to explore the anti-inflammatory and anti-oxidant effects of FTF-EtOH. Possible anti-inflammatory mechanisms of FTF targeting NLRP3 inflammasome, Nrf2, and NF-κB have been determined using western blot, quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR), immunofluorescence assay, nuclear and cytoplasmic extraction, and ubiqutination assay.

RESULTS

FTF-EtOH suppressed CS-induced overproduction of inflammatory factors [e.g., tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β)], and upregulation of the content of intracellular MDA in the lung homogenate of mice. In cell-based models, FTF-EtOH reduced the lipopolysaccharide (LPS)-induced overproduction of inflammatory factors, and attenuated the CS extract-induced overgeneration of reactive oxygen species (ROS). Furthermore, FTF-EtOH up-regulated Nrf2 and its downstream genes through enhancing the stability of Nrf2 protein, and inhibited the activation of NF-κB and NLRP3 inflammasome, which have been confirmed by detecting the protein levels in the mouse model.

CONCLUSIONS

FTF-EtOH effectively attenuated lung inflammation in vitro and in vivo. The protection of FTF-EtOH against inflammation was produced by activation of Nrf2 and inhibitions of NF-κB and NLRP3 inflammasome. These datas definitely support the ethnopharmacological use of FTF as an anti-inflammatory drug for treating respiratory diseases in TCM.

Synthesis of 1,2,3,triazole modified analogues of hydrochlorothiazide via click chemistry approach and in-vitro α-glucosidase enzyme inhibition studies

The current study was aimed to discover potent inhibitors of α-glucosidase enzyme. A 25 membered library of new 1,2,3-triazole derivatives of hydrochlorothiazide (1) (HCTZ, a diuretic drug also being used for the treatment of high blood pressure) was synthesized through click chemistry approach. The structures of all derivatives 2-26 were deduced by MS, IR, ¹H-NMR, and ¹³C-NMR spectroscopic techniques. All the compounds were found to be new. Compounds 1-26 were evaluated for α-glucosidase enzyme inhibition activity. Among them, 18 compounds showed potent inhibitory activity against α-glucosidase with IC₅₀ values between 24 and 379 µM. α-Glucosidase inhibitor drug acarbose (IC₅₀ = 875.75 ± 2.08 μM) was used as the standard. Kinetics studies of compounds 6, 9, 11, 12, 15, 20, 23, and 24 revealed that only compound 15 as a mixed-type of inhibitor, while others were non-competitive inhibitors of α-glucosidase enzyme. All the compounds were found to be non-cytotoxic when checked against mouse fibroblast 3T3 cell line.

A review of the ethnobotanical value, phytochemistry, pharmacology, toxicity and quality control of Tussilago farfara L. (coltsfoot)

ETHNOPHARMACOLOGICAL RELEVANCE

Tussilago farfara L. (commonly called coltsfoot), known as a vital folk medicine, have long been used to treat various respiratory disorders and consumed as a vegetable in many parts of the world since ancient times.

AIM OF THE REVIEW

This review aims to provide a critical evaluation of the current knowledge on the ethnobotanical value, phytochemistry, pharmacology, toxicity and quality control of coltsfoot, thus provide a basis for further investigations.

MATERIALS AND METHODS

A detailed literature search was obtained using various online search engines (e.g. Google Scholar, Web of Science, Science Direct, Baidu Scholar, PubMed and CNKI). Additional information was sourced from ethnobotanical literature focusing on Chinese and European flora. The plant synonyms were validated by the database 'The Plant List' (www.theplantlist.org).

RESULTS

Coltsfoot has diverse uses in local and traditional medicine, but similarities have been noticed, specifically for relieving inflammatory conditions, respiratory and infectious diseases in humans. Regarding its pharmacological activities, many traditional uses of coltsfoot are supported by modern in vitro or in vivo pharmacological studies such as anti-inflammatory activities, neuro-protective activity, anti-diabetic, anti-oxidant activity. Quantitative analysis (e.g. GC-MS, UHPLC-MRM^HR) indicated the presence of a rich (>150) pool of chemicals, including sesquiterpenes, phenolic acids, flavonoids, chromones, pyrrolizidine alkaloids (PAs) and others from its leaves and buds. In addition, adverse events have resulted from a collection of the wrong plant which contains PAs that became the subject of public concern attributed to their highly toxic.

CONCLUSIONS

So far, remarkable progress has been witnessed in phytochemistry and pharmacology of coltsfoot. Thus, some traditional uses have been well supported and clarified by modern pharmacological studies. Discovery of therapeutic natural products and novel structures in plants for future clinical and experimental studies are still a growing interest. Furthermore, well-designed studies in vitro particularly in vivo are required to establish links between the traditional uses and bioactivities, as well as ensure safety before clinical use. In addition, the good botanical identification of coltsfoot and content of morphologically close species is a precondition for quality supervision and control. Moreover, strict quality control measures are required in the studies investigating any aspect of the pharmacology and chemistry of coltsfoot.

Chemical comparison of the raw and processed Farfarae Flos by liquid chromatography-mass spectrometry based metabolomic approach

Farfarae Flos (FF) has been used in China for a long time as an anti-tussive and expectorant herbal drugs, and it was usually honey-fried FF (HFF). To clarify the mechanism of honey processing, it is important to know the chemical difference between FF and HFF firstly. In this study, UHPLC-Orbitrap-MS was used to characterize the chemical compounds in FF, honey and HFF. Then the metabolomic approach based on UHPLC-Orbitrap-MS revealed 68 differential compounds between the FF and HFF, and chemical reactions occurring during processing were also proposed to elucidate the honey processing mechanisms of FF. In order to investigate the chemical difference between FF and HFF comprehensively and accurately, the components derived from the honey and the moisture content in FF and HFF were considered for the first time. In summary, this study investigated the chemical differences between FF and HFF in a holistic way, which laid the basis for the quality control of HFF and further explaining the honey processing mechanisms of FF. In addition, eight native compounds derived from the honey could be used as the index to authenticate the HFF prepared by the genuine honey.

The galloyl moiety enhances the inhibitory activity of catechins and theaflavins against α-glucosidase by increasing the polyphenol-enzyme binding interactions

The inhibition properties of 10 tea polyphenols against α-glucosidase were studied through inhibition assay, inhibition kinetics, fluorescence quenching and molecular docking. It was found that the inhibitory activity of polyphenols with a 3 and/or 3' galloyl moiety (GM) was much higher than that without a GM. The GM could enter into the active site of α-glucosidase and bind with the catalytic amino acid residues through hydrogen bonding and π-conjugation, thus playing an important role in the competitive inhibition of catechins and theaflavins. The positive linear correlations among the constants characterizing the inhibitory activity and binding affinity of tea polyphenols to α-glucosidase indicate that enzyme inhibition by polyphenols is caused by the binding interactions between them, and that the combination of the characterization methods for polyphenol-glucosidase binding is reasonable. In addition, the in vivo hypoglycemic effects of galloylated polyphenols suggest that the GM may be considered as a pharmaceutical fragment for the alleviation of type II diabetes symptoms through α-glucosidase inhibition.

Construction of Fe3O4@α-glucosidase magnetic nanoparticles for ligand fishing of α-glucosidase inhibitors from a natural tonic Epimedii Folium

Inhibition of α-glucosidase activity is an effective way for treatment of type 2 diabetes mellitus. Epimedii Folium is an important source of α-glucosidase inhibitors (AGIs), however bioactive compounds and pharmacological mechanisms remained unclear. In this study, a novel strategy was established, which harnessed α-glucosidase functionalized magnetic beads to fish out potential AGIs, followed by UPLC-MS/MS analysis for their identification. Furthermore, molecular docking was employed to predict binding patterns between the AGIs and the enzyme, and IC₅₀ values was estimated as well. After response surface methodology optimization, the highest activity of Fe₃O₄@α-glucosidase has been achieved when 1.17 mg/mL of α-glucosidase was immobilized in phosphate buffer (pH 6.81) for 4.22 h. Moreover, eight flavonoids were fished out from the extract of Epimedii Folium, and then identified to be epimedin A, epimedin B, epimedin C, icariin, sagittatoside A, sagittatoside B, 2"-O-rhamnosyl icariside II and baohuoside I. All of them were further confirmed to be AGIs through in vitro inhibitory assay and molecular docking. Among those, baohuoside I and sagittatoside B possessed stronger inhibitory activity than acarbose. The approach has a significant prospect in conveniently screening bioactive compounds that target various receptors, which provided an efficient platform for new drug development from natural products.

Farfarae Flos: A review of botany, traditional uses, phytochemistry, pharmacology, and toxicology

ETHNOPHARMACOLOGICAL RELEVANCE

Farfarae Flos (FF; dried flower buds of Tussilago farfara L.), a widely used traditional Chinese medicine (TCM), is also known as "Kuandonghua" (Chinese: ). It has a wide range of pharmacological effects and has long been used to treat various respiratory conditions including cough, asthma, and acute or chronic bronchitis.

AIMS

This study reviews the current advances in the research on the botany, ethnopharmacology, phytochemistry, pharmacology, and toxicology of Farfarae Flos. Prospects for future investigation and application of this herb are also discussed.

MATERIALS AND METHODS

Information on FF was collected from both published materials (such as ancient and modern books, Ph.D. and M. Sc. dissertations, monographs on medicinal plants, and pharmacopoeia) and electronic databases (such as CNKI, SciFinder, WanFang data, PubMed, ScienceDirect, Web of Science, Taylor&Francis, ACS Publications, Wiley, Springer, Europe PMC, EBSCOhost, J-STAGE, and Google Scholar).

RESULTS

Approximately 175 chemical compounds, including terpenoids, organic acids, flavonoids, alkaloids, chromones, volatile oils, and other compounds, have been isolated from FF. This TCM has been reported to produce pharmacological effects on the respiratory, cardiovascular, and digestive systems, and exert antioxidant, anti-inflammatory, and neuroprotective activities. FF is safe in the traditional dose range, but the potential toxicity due to the emergence of pyrrolidine alkaloids needs to be paid more attention.

CONCLUSIONS

FF is a commonly used TCM with pharmacological activities mainly on the respiratory system. This study suggests that the further expansion of the pharmacological effect of FF and in-depth study of its prescription need to be concerned about. The investigations of the role of more active substances and the pharmacokinetics of the hepatotoxic components of FF will help to maximize the therapeutic potential and promote its popularization and application. Meanwhile, it is important to pay attention to pursue research on the similarities and differences between the leaves and the flower buds to find their respective advantages and make rational use of T. farfara L.

Cellular Target Proteome in Breast Cancer Cells of an Oplopane Sesquiterpenoid Isolated from Tussilago farfara

Tussilago farfara is a traditional herbal medicine used to treat coughs, bronchitis, and asthma. Its bioactive compounds include sesquiterpenoids with anti-inflammatory, antiproliferative, neuroprotective, and other effects. Biochemical studies have highlighted the mechanisms of action, but the investigations of related molecular pathways have not specified direct molecular targets. Therefore, this study profiled cellular target proteins of a sesquiterpenoid isolated from T. farfara using quantitative chemical proteomics in MDA-MB-231 and MCF-7 human breast cancer cells. Compound 8, 7β-(3'-ethyl-cis-crotonoyloxy)-1α-(2'-methyl butyryloxy)-3,14-dehydro-Z-notonipetranone, exhibited potent antiproliferative activity based on its α,β-unsaturated carbonyl moiety, and its potential cellular target proteins were identified using a compound 8-based clickable probe. Among >200 identified proteins, 17 showed enrichment ratios of >3 in both cell lines, while recombinant 14-3-3 protein zeta and peroxiredoxin-1 were verified using isothermic calorimetry and their alkylation sites. Considering the interaction between the α,β-unsaturated carbonyl moiety of compound 8 and cysteine residues of the proteins, peptides containing Cys25 and Cys94 of 14-3-3 protein zeta and Cys83 of peroxiredoxin-1 were significantly reduced by this sesquiterpene ester. Although the results did not elucidate the effects of compound 8 in breast cancer cells, identification of potential target proteins contributes to enhanced understanding of its antiproliferative and anti-inflammatory effects.

Antimicrobial potential of different medicinal plants against food industry pathogens

Work aimed to investigate the antimicrobial activity of medicinal plants against selected species of food industry pathogens in vitro conditions. The detection of antibacterial properties was examined by the disc diffusion method and the method of the minimum inhibitory concentrations (MIC). The cultivation of microorganisms after the 24 h was performed by disc diffusion method. Petri dishes have grown at 37 °C in which the Mueller - Hinton agar and application it to the sterile paper disc impregnated with the extract.  The thickness of the resulting inhibition zone was measured with a ruler after completion of the culture. After the preparation of bacteria and extracts of certain concentrations of a subsequently added to wells microplates we use the method of the minimum inhibitory concentration (MIC) which was conducted out as the second measurement, and we took the readings absorbance spectrophotometer at 570 nm using the Glomax plate spectrophotometer. We found out, that Equisetum arvense demonstrated the largest zones of inhibition to the tested Gram-positive and Gram-negative bacteria. The greatest antimicrobial activity achieved Equisetum arvense, Urtica dioica, and Taraxacum officinale against Salmonella enterica subsp. enterica CCM 3807 and Yersinia enterocolitica CCM 5671. Equisetum arvense and Taraxacum officinale was the most effective against Escherichia coli CCM 2024 and the least effective were Tussilago farfara and Mentha piperita with using the method of minimum inhibitory concentrations.

Mass Spectrometry and 1H-NMR Study of Schinopsis lorentzii (Quebracho) Tannins as a Source of Hypoglycemic and Antioxidant Principles

The ethyl acetate extract of the commercial tannin Tan’Activ QS-SOL (from Schinopsis lorentzii wood), employed for the production of red wine, was subjected to chromatography on Sephadex LH-20, providing nine fractions (A-1–A-9), which were estimated for total phenols content (GAE), antioxidant activity (DPPH, ORAC), and hypoglycemic activity (α-glucosidase and α-amylase inhibition). All the fractions were analyzed by means of HPLC/ESI-MS/MS and ¹H-NMR to identify the principal active constituents. Fractions A-1 and A-3 showed the highest antioxidant activity and gallic acid (1), pyrogallol (3), eriodictyol (6), catechin (12), and taxifolin (30) were identified as the major constituents. The highest α-glucosidase and α-amylase inhibitory activity was observed in fractions A-7–A-9 containing condensed (9′, 15, 18, 19, 23, and 27) hydrolysable tannins (13 and 32) as well as esters of quinic acid with different units of gallic acid (5, 11, 11′, 14, and 22). This last class of gallic acid esters are here reported for the first time as α-glucosidase and α-amylase inhibitors.

Development and Validation of Liquid Chromatography-Tandem Mass Spectrometry Method for Pharmacokinetic Evaluation of 7β-(3-Ethyl-cis-crotonoyloxy)-1α-(2-methylbutyryloxy)-3,14-dehydro-Z-notonipetranon in Rats

Recently, potent neuroprotective and anti-diabetic effects of 7β-(3-Ethyl-cis-crotonoyloxy)-1α-(2-methylbutyryloxy)-3,14-dehydro-Z-notonipetranone (ECN), a sesquiterpenoid isolated from Tussilago farfara Linnaeus, have been elucidated. To facilitate further pre-clinical evaluation in rats, an analytical method for the determination of ECN in rat plasma was developed and optimized by using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Plasma samples were pretreated by the protein precipitation method with an acetonitrile solution of losartan (LST) as the internal standard. Chromatographic separation was performed using a an Octadecyl-silica (ODS) column (2.6 µm, 100 x 4.6 mm) in the isocratic mode. The mobile phase, comprising 10 mM ammonium formate in water pH 5.75) and acetonitrile (11:89, v/v), was eluted at a flow rate of 0.4 mL/min. Mass spectrometric detection was performed in the multiple reaction monitoring mode with positive electrospray ionization, and the mass transitions of ECN and LST were m/z 431.3 to 97.3 and m/z 423.1 to 207.2, respectively. The calibration curves of spiked plasma samples were linear in the 10.0–10,000 ng/mL range (r² > 0.996). The lower limit of quantification (LLOQ) was determined as 10.0 ng/mL. Validation was conducted in the LLOQ, and three quality control (QC) sample levels (10.0, 25.0, 3750, and 7500 ng/mL) were studied. Among them, the relative standard deviation for the within- and between-run precisions was under 9.90%, and the relative error of the accuracies was within the −8.13% to 0.42% range. The validated method was successfully employed to investigate the pharmacokinetic properties of ECN in rats, which revealed the linear pharmacokinetic behavior of ECN for the first time.

Novel Flavonoid Glycosides of Quercetin from Leaves and Flowers of Gaiadendron punctatum G.Don. (Violeta de Campo), used by the Saraguro Community in Southern Ecuador, Inhibit α-Glucosidase Enzyme

Gaiadandendron punctatum G.Don. (violeta de campo) is a plant used in traditional medicine by the Saraguro people, an ancient indigenous group that lives in southern Ecuador. From samples collected in the region, six glycoside flavonoids, five with quercetin and one with kaempferol as aglycon, were isolated and characterized from hydroalcoholic extracts of leaves and flowers. Rutin (2) was found in flowers and leaves, nicotiflorin (1) was found in flowers, artabotryside A (3) was found in leaves, and three novel quercetin flavonoid glycosides were isolated, elucidated, and characterized via 1D and 2D NMR experiments (¹H, ¹³C, COSY, DEPT, HMBC, HSQC, TOCSY, NOESY, ROESY), acid hydrolysis–derivatization–GC-MS analysis, HPLC-MS, IR, UV, and optical rotation. The new quercetin flavonoid glycosides were named hecpatrin (4) (isolated from leaves), gaiadendrin (5) (isolated from leaves), and puchikrin (6) (isolated from flowers). The hydroalcoholic extracts of the leaves presented antimicrobial activity against Micrococcus luteus, Staphylococcus aureus, and Enterococcus faecalis and the hydroalcoholic extract of the flowers was active against Micrococcus luteus. However, glycoside flavonoids presented scarce antimicrobial activity against bacteria. Hydroalcoholic extracts from leaves and flowers and their secondary metabolites showed inhibition against the α-glucosidase enzyme at different concentrations. Rutin, gaiadendrin, and nicotiflorin showed competitive α-glucosidase inhibition, while hecpatrin presented non-competitive inhibition.

LUTI: a double-function inhibitor isolated from naked flax seeds

Acute glucose fluctuation during the postprandial period causes a risk for type 2 diabetes mellitus (T2DM). α-Glucosidase inhibitors have been approved as therapeutic agents for diabetes. In the present study, a protein with α-glucosidase inhibitory activity from Flax (Linum usitatissimum) seeds was isolated using a one-step purification with Q-Sepharose4B column, followed by Sephacryl S-200 size-exclusion chromatography. It was identified as a trypsin inhibitor, named L. usitatissimum trypsin inhibitor (LUTI). The half maximal inhibitory concentration (IC50) of LUTI was 113.92 μM for α-glucosidase and 6.17 μM for trypsin. Lineweaver-Burk kinetic experiment showed that the protein exhibited two distinct inhibitory modes, a competitive inhibitor type for α-glucosidase and a non-competitive type for trypsin. The interaction between LUTI and α-glucosidase was detected through gel filtration chromatography and dynamic light scattering. Increased glucose consumption and lactic acid production were also observed following LUTI treatment in Caco-2 and HepG2 cells. LUTI inhibits not only the activity of trypsin but also the activity of α-glucosidase. It is expected that LUTI will become an oral hypoglycemic polypeptide drug for T2DM.

Biologically active compounds from two members of the Asteraceae family: Tragopogon dubius Scop. and Tussilago farfara L

Tragopogon dubius and Tussilago farfara are consumed as vegetables and used in folk medicine to manage common diseases. Herein, the chemical compositions and biological activities of different leaf extracts (ethyl acetate, methanol, and water) of T. dubius and T. farfara were evaluated. The antibacterial, antifungal, and antioxidant abilities of the extracts were tested using different assays including free radical scavenging, reducing power, phosphomolybdenum, and metal chelating assays. Enzyme inhibitory potentials were evaluated against cholinesterases, tyrosinase, α-amylase and α-glucosidase. Complexes of bioactive compounds (chlorogenic and rosmarinic acid) were docked into the enzymatic cavity of α-glucosidase and subjected to molecular dynamic calculation, enzyme conformational stability, and flexibility analysis. T. dubius and T. farfara extracts showed remarkable antioxidant potentials. Ethyl acetate extracts of T. dubius and T. farfara were the most potent inhibitors of acetylcholinesterase and butyrylcholinesterase. T. dubius ethyl acetate extract and T. farfara methanolic extract showed noteworthy activity against α-glucosidase. High performance liquid chromatography analysis revealed the abundance of some phenolic compounds including chlorogenic and rosmarinic acids. Ethyl acetate extract of T. dubius showed notable antifungal activity against all strains. Docking studies showed best pose for chlorogenic acid was stabilized by a network of hydrogen bonds with residues Asp1157, Asp1279, whereas rosmarinic acid showed several hydrogen bonds with Asp1157, Asp1420, Asp1526, Lys1460 and Trp1369. This study further validates the use of T. dubius and T. farfara in traditional medicine, as well as act as a stimulus for further studies for future biomedicine development. Communicated by Ramaswamy H. Sarma.

α-Glucosidase inhibitors: consistency of in silico docking data with in vitro inhibitory data and inhibitory effect prediction of quercetin derivatives

The relationship between in silico and in vitro experiments regarding the inhibitory effects of polyphenols on α-glucosidase was investigated.

The kinetics and mechanism of α-glucosidase inhibition by F5-SP, a novel compound derived from sericin peptides

The inhibition of α-glucosidase decreases postprandial blood glucose and therefore plays an important role in the treatment of type 2 diabetes mellitus. The present study investigated and characterized a peptide fraction of sericin hydrolysate, the kinetics of peptide-induced inhibition of α-glucosidase, and the interaction mechanism between the peptides and α-glucosidase. The fraction that eluted with 0.4 M NaCl (F5-SPs) on a DEAE-cellulose column exhibited significant inhibitory activity with an IC₅₀ of 41 ± 1.94 μg mL^-1. A kinetics analysis revealed that the F5-SP-induced inhibition was a reversible and parabolic mixed-type inhibition with a K_i value of 86.63 ± 0.014 μg mL^-1. F5-SPs can bind to α-glucosidase at multiple sites to alter the conformation of α-glucosidase. F5-SPs were found to be rich in Gly, Ser, Glu, Tyr, Arg, and Pro, and had a sericin-conserved sequence SEDSSEVDIDLGNLG, as analyzed by Nano LC-MS/MS. Fluorescence spectra analysis showed that F5-SPs quenched the intrinsic fluorescence of α-glucosidase by a static quenching mechanism, and circular dichroism analysis suggested that the binding of F5-SPs to α-glucosidase resulted in the alteration of the secondary structure of an enzyme. The results of this study support the dietary recommendation of F5-SPs for the treatment of type 2 diabetes.

Bioactive Phenolics of the Genus Artemisia (Asteraceae): HPLC-DAD-ESI-TQ-MS/MS Profile of the Siberian Species and Their Inhibitory Potential Against α-Amylase and α-Glucosidase

Artemisia genus of Asteraceae family is a source of medicinal plants known worldwide and used as ethnopharmacological remedies for the treatment of diabetes in Northern Asia (Siberia). The aim of this study was to determine the phenolic profile of 12 Siberian Artemisia species (A. anethifolia, A. commutata, A. desertorum, A. integrifolia, A. latifolia, A. leucophylla, A. macrocephala, A. messerschmidtiana, A. palustris, A. sericea, A. tanacetifolia, A. umbrosa) and to test the efficacy of plant extracts and pure compounds for antidiabetic potential. Finally, by HPLC-DAD-ESI-TQ-MS/MS technique, 112 individual phenolic compounds were detected in Artemisia extracts in a wide range of concentrations. Some species accumulated rare plant phenolics, such as coumarin-hemiterpene ethers (lacarol derivatives) from A. latifolia and A. tanacetifolia; melilotoside from A. tanacetifolia; dihydrochalcones (davidigenin analogs) from A. palustris; chrysoeriol glucosides from A. anethifolia, A. sericea, and A. umbrosa; eriodictyol glycosides from A. messerschmidtiana; and some uncommon flavones and flavonols. The predominant phenolic group from Artemisia species herb was caffeoylquinic acid (CQAs), and in all species, the major CQAs were 5-O-CQA (20.28-127.99 μg/g) and 3,5-di-O-CQA (7.35-243.61 μg/g). In a series of in vitro bioassays, all studied Artemisia extracts showed inhibitory activity against principal enzymes of carbohydrate metabolism, such as α-amylase (IC₅₀ = 150.24-384.14 μg/mL) and α-glucosidase (IC₅₀ = 214.42-754.12 μg/mL). Although many phenolic compounds can be inhibitors, experimental evidence suggests that the CQAs were key to the biological response of Artemisia extracts. Mono-, di- and tri-substituted CQAs were assayed and showed inhibition of α-amylase and α-glucosidase, with IC₅₀ values of 40.57-172.47 μM and 61.08-1240.35 μM, respectively, and they were more effective than acarbose, a well-known enzyme inhibitor. The results obtained in this study reveal that Siberian Artemisia species and CQAs possess a pronounced inhibitory activity against α-amylase and α-glucosidase and could become a complement to synthetic antidiabetic drugs for controlling blood glucose level.

Influence of Clitoria ternatea Flower Extract on the In Vitro Enzymatic Digestibility of Starch and Its Application in Bread

This study aimed to assess the effect of the Clitoria ternatea L. flower extract (CTE), on the inhibition of pancreatic α-amylase, in vitro starch hydrolysis, and predicted the glycemic index of different type of flours including potato, cassava, rice, corn, wheat, and glutinous rice flour. The application in a bakery product prepared from flour and CTE was also determined. The results demonstrated that the 1% and 2% (w/v) CTE inhibited the pancreatic α-amylase activity by using all flours as a substrate. Moreover, 0.5%, 1%, and 2% (w/v) CTE showed a significant reduction in the glucose release, hydrolysis index (HI), and predicted glycemic index (pGI) of flour. In glutinous rice flour, 1% and 2% (w/v) CTE had a significantly lower level of rapidly digestible starch (RDS) and slowly digestible starch (SDS) with a concomitant higher level of undigested starch. The statistical analysis demonstrated strong positive significant correlations between the percentage of CTE and the undigested starch of wheat and cassava. The addition of 5%, 10%, and 20% (w/w) CTE significantly reduced the rate of starch digestion of the wheat bread. The pGI of bread incorporated with 5% CTE (w/w) was significantly lower than that of the control bread. Our findings suggest that CTE could reduce the starch digestibility, the HI, and pGI of flour through the inhibition of carbohydrate digestive enzymes. Taken together, CTE may be a potent ingredient for the reduced glycemic index of flours.

Physicochemical Characterization, Microbiological Quality and Safety, and Pharmacological Potential of Hancornia speciosa Gomes

Hancornia speciosa Gomes is a fruit tree, commonly known as the mangaba tree, which is widespread throughout Brazil. The leaves of this plant are used in traditional medicine for medicinal purposes. Thus, the objective of this study was to perform a physicochemical characterization, identify the lipophilic antioxidants and fatty acids, and determine the microbiological quality and safety of H. speciosa leaves. In addition, the antioxidant, antimutagenic, and inhibitory activities of the ethanolic extract of H. speciosa leaves (EEHS) against enzymes related to neurodegenerative diseases, inflammation, obesity, and diabetes were investigated. Furthermore, this study aimed at assessing the in vivo effects of the EEHS on the glycemia of normoglycemic and diabetic Wistar rats. Physicochemical characterization was performed by colorimetry and gas-liquid chromatography with flame ionization detection (GC-FID). The total number of colonies of aerobic mesophiles, molds, and yeasts was determined. The total coliforms and Escherichia coli were counted using the SimPlates kit, and sulphite-reducing Clostridium spores were quantified using the sulphite-polymyxin-sulfadiazine agar method. Salmonella spp. were detected using the 1-2 Test. The antioxidant activity of the EEHS was measured by its inhibition of 2,2'-azobis(2-amidinopropane) dihydrochloride- (AAPH-) induced oxidative hemolysis of human erythrocytes. The antimutagenic activity was determined using the Ames test. The acetylcholinesterase, butyrylcholinesterase, tyrosinase, hyaluronidase, lipase, α-amylase, and α-glycosidase enzyme-inhibiting activities were assessed and compared with commercial controls. The in vivo effects of the EEHS were assessed using the oral glucose tolerance test in normoglycemic Wistar rats and measuring the blood glucose levels in diabetic rats. The results demonstrated physical-chemical parameters of microbiological quality and safety in the leaves of H. speciosa, as well as antioxidant and antimutagenic activities and inhibition of enzymes related to neurodegenerative diseases, inflammation, obesity, and diabetes. In in vivo assays, it was shown that the normoglycemic rats challenged with glucose overload show significantly decreased blood glucose levels when treated with the EEHS. Taken together, the results ensure the microbiological quality and safety as well as showing the contents of carotenoids and polyunsaturated fatty acids of H. speciosa leaves. Additionally, the antioxidant, antimutagenic, anti-inflammatory, anti-Alzheimer's disease, anti-Parkinson's disease, antiobesity, and antihyperglycemic activities of the EEHS were demonstrated.

Zanthoxylum armatum DC extracts from fruit, bark and leaf induce hypolipidemic and hypoglycemic effects in mice- in vivo and in vitro study

Background

Zanthoxylum armatum DC is an important medicinal plant of south East Asia, and has been used to treat various ailments in traditional medicine including diabetes. This study investigated the in vitro and in vivo antidiabetic and biochemical effects of extracts of Z. armatum in mice.

Method

The extracts of fruit, bark and leaf from Z. armatum were tested for α-glucosidase inhibition activity. Albino mice of either sex weighing (26–30 g) assigned into groups. Diabetes was induced by IP injection of alloxan monohydrate (150 mg/kg). The extracts (500 mg/kg) and standard (Glibenclamide 10 mg/kg) were administered to mice for 15 days. Serum biochemical parameters were monitored for the period of study.

Results

The leaves and bark extracts showed maximum α-glucosidase inhibition (96.61 ± 2.13 and 93.58 ± 2.31% respectively). The extracts treated and the standard treated groups showed significant decrease in the fasting blood glucose levels compared to diabetic control. The effect was more pronounced in mice treated with leaves extract. In the in vivo studies body weights of diabetic mice treated with Z. armatum extracts and the standard did not reduced to extent as observed in diabetic control and this difference was significant (p < 0.05). There was a significance (p < 0.001) improvement in blood hemoglobin, urea, creatinine, cholesterol, and triglycerides of the extracts treated diabetic mice. The extracts showed hypolipidemic effect by reducing the LDL level. The extracts produced no prominent changes in proteins levels.

Conclusion

It can be concluded that Z. armatum extracts showed excellent antidiabetic potential in vivo and in vitro and could be considered for further appraisal in clinical assessment and drug development.

Intestinal α-Glucosidase Inhibitors in Achillea millefolium

Achillea millefolium is a plant used as a component of anti-diabetic preparation but the bioactive compounds responsible for its use are not known. Inhibition of intestinal α-glucosidase is a preferable effect for prevention and treatment of diabetes, and A. millefolium extract showed inhibitory activity against the enzyme. Activity-guided separation of the extract gave four mono- or di-caffeoylquinic acids as the isolate. Quantitation of these four caffeoylquinic acids and the activity of the isolates suggested that these are the major contributor for the α-glucosidase inhibitory activity in the extract. However also, the presence of unidentified, minor, but potent α-glucosidase inhibitor in the isolate was also suggested.

Chemical Composition and Biological Activities of Mono- and Heterofloral Bee Pollen of Different Geographical Origins

Recent research shows variations in pollen chemical constituents and, consequently, in their therapeutic properties. Mono and multifloral bee pollen extracts were investigated for antioxidant and enzyme inhibitory activity properties, phenolic compounds and fatty acid composition. Generally, Eucalyptus spp. and multifloral extracts exhibited potent inhibitory activity against α-amylase, acetylcholinesterase, tyrosinase, lipoxygenase, lipase and hyaluronidase. On the other hand, Miconia spp. demonstrated higher antihemolytic activity. Cocos nucifera and Miconia spp. extracts exhibited important antioxidant properties in the different assays (ABTS, DPPH, β-carotene/linoleic acid and reducing power). Moreover, these extracts had greater amounts of total phenols and flavonoids in comparison to others. The increase in antioxidant activity (decrease in EC₅₀ values) was accompanied by an increase in the amount of total phenols in the extracts. The pollen extracts contained linoleic acid and α-linolenic acid as major fatty acids, followed by palmitic acid, and oleic acid. In this study, differences were observed in both chemical constituents and biological activities of the samples related to the geographical and botanical origin of bee pollen.

Metabolomics reveal the protective effect of Farfarae Flos against asthma using an OVA-induced rat model

A ¹H NMR based metabolomics approach combined with biochemical assay and histopathological inspection has been employed to study the protective effect of PEFF against asthma on a rat model.

Chemical Constituents of the Leaves of Tussilago farfara and their Aldose Reductase Inhibitory Activity

The inhibitory activity of 37 medicinal plant extracts against aldose reductase (AR) activity was evaluated. The most potent AR inhibitory activity was found in the MeOH extract of the leaves of Tussilago farfara (Compositae). Enzyme assay-guided fractionation of the extract led to the isolation of a new flavonoid glycoside, kaempferol 3- O-[3,4- O-(isopropylidene)-α-L-arabinopyranoside] (1), along with 15 known compounds (2–16), of which 3, 5, 13, 15, and 16 were isolated from T. farfara for the first time. The structures of 1–16 were elucidated based on MS and NMR data. Dicaffeoylquinic acid derivatives (7–12) showed potent AR inhibitory activity with IC50 values ranging from 0.58 to 5.38 μM, whereas flavonoid glycosides 1, 3, 5, and 6 showed weak inhibitory activity with IC50 values of 13.9, 15.1, 13.3, and 14.1 μM, respectively.

Glandular trichomes of Tussilago Farfara (Senecioneae, Asteraceae)

The glandular trichomes are developed on the aerial organs of Tussilago farfara ; they produce phenols and terpenoids. Smooth endoplasmic reticulum and leucoplasts are the main organelles of the trichome secretory cells. The aim of this study was to characterise the morphology, anatomy, histochemistry and ultrastructure of the trichomes in Tussilago farfara as well as to identify composition of the secretory products. Structure of trichomes located on the peduncles, bracts, phyllaries, and leaves were studied by light and electron microscopy. The capitate glandular trichomes consist of a multicellular head and a biseriate long stalk. Histochemical tests and fluorescence microscopy reveal phenols and terpenoids in the head cells. During secretory stage, the head cells contain smooth and rough endoplasmic reticulum, Golgi apparatus, diversiform leucoplasts with opaque contents in lamellae, chloroplasts, mitochondria, and microbodies. In the capitate glandular trichomes of T. farfara subcuticular cavity is absent, unlike glandular trichomes in other Asteraceae species. For the first time, content of metabolites in the different vegetative and reproductive organs as well as in the isolated capitate glandular trichomes was identified by GC-MS. Forty-five compounds, including organic acids, sugars, polyols, phenolics, and terpenoids were identified. It appeared that metabolite content in the methanol extracts from peduncles, bracts and phyllaries is biochemically analogous, and similar to the metabolites from leaves, in which photosynthesis happens. At the same time, the metabolites from trichome extracts essentially differ and refer to the above-mentioned secondary substances. The study has shown that the practical value of the aerial organs of coltsfoot is provided with flavonoids produced in the capitate glandular trichomes.

Inhibitory activities of caffeoylquinic acid derivatives from Ilex kudingcha C.J. Tseng on α-glucosidase from Saccharomyces cerevisiae

Polyphenols and caffeoylquinic acid (CQA) derivatives (3-CQA, 4-CQA, 5-CQA, 3,4-diCQA, 3,5-diCQA, and 4,5-diCQA) were prepared from Ilex kudingcha C.J. Tseng, and their effects and mechanisms on the activities of α-glucosidase from Saccharomyces cerevisiae were investigated in the present study. As results, the IC50 values for CQA derivatives were 0.16-0.39 mg/mL, and the inhibition mode of CQA derivatives was noncompetitive. On the basis of fluorescence spectroscopy and circular dichroism spectroscopy data, the binding constants and number of binding sites were calculated to be 10(6)-10(8) M(-1) and 1.42-1.87, respectively. CQA derivatives could bind to the enzyme mainly through hydrophobic interaction, altering the microenvironment and molecular conformation of the enzyme, thus decreasing the catalytic activity. To the authors' knowledge, this is the first report on α-glucosidase inhibitory mechanism by CQA derivatives from I. kudingcha, and the findings suggest a potential use of kudingcha as functional foods for the prevention and treatment of diabetes and related symptoms.

Investigation into the Antioxidant and Antidiabetic Potential of Moringa stenopetala: Identification of the Active Principles

The fresh leaves of Moringa stenopetala (family, Moringaceae) are commonly eaten as cabbage while dried leaves are used as nutritional supplement and for treating a variety of disease conditions including diabetes. The present investigation into the therapeutic potential of the leaves and seeds of the plant revealed no inhibitory effect against α-glucosidase enzyme up to the concentration of 200 μg/mL but the leaves extract displayed potent DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging effect (IC50, 59.5 ± 4.1 μg/mL). An activity directed fractionation and isolation procedure resulted in the identification of the major antioxidant compound as rutin and minor active component, neochlorogenic acid. Both the crude extract (0.8–200 μg/mL) and rutin (0.8–200 μM) but not neochlorogenic acid displayed a concentration-dependent protection of human pancreatic β-cells (1.4E7 cells) from oxidant-induced cell death. The identification of these compounds along with their potential role in the nutritional and medicinal significance of the plant is discussed.

Effect of lithium salts addition on the ionic liquid based extraction of essential oil from Farfarae Flos

In this study, an ionic liquids (ILs) based extraction approach has been successfully applied to the extraction of essential oil from Farfarae Flos, and the effect of lithium chloride was also investigated. The results indicated that the oil yields can be increased by the ILs, and the extraction time can be reduced significantly (from 4h to 2h), compared with the conventional water distillation. The addition of lithium chloride showed different effect according to the structures of ILs, and the oil yields may be related with the structure of cation, while the chemical compositions of essential oil may be related with the anion. The reduction of extraction time and remarkable higher efficiency (5.41-62.17% improved) by combination of lithium salt and proper ILs supports the suitability of the proposed approach.