Homo‐C‐nucleoside analogs IV. Synthesis of 4‐(2,5‐anhydro‐D‐altro‐pentitol‐1‐yl)‐2‐phenyl‐2H‐1,2,3‐triazole homo‐C‐nucleoside. CD assignment of the absolute configuration of the carbon bridge

Dehydrative cyclization of 4‐(D‐altro ‐pentitol‐1‐yl)2‐phenyl‐2H ‐1,2,3‐triazole in basic medium with one moler equivalent of p‐toluene sulfonyl chloride in pyridine solution gave the homo‐C‐ nucleoside 4‐(2,5‐anhydro‐D‐altro ‐1‐yl)‐2‐phenyl‐2H ‐1,2,3‐triazole. The structure and anomeric configuration was determined by acylation, nuclear magnetic resonance (NMR), and mass spectroscopy. The stereochemistry at the carbon bridge of homo‐C‐ nucleoside 2‐phenyl‐2H ‐1,2,3‐triazoles was determined by circular dichroism (CD) spectroscopy.     

Asymmetric catalysis of homo‐coupling of 3‐substituted naphthylamine and hetero‐coupling with 3‐substituted naphthol leading to 3,3′‐dimethyl‐2,2′‐diaminobinaphthyl and ‐2‐amino‐2′‐hydroxybinaphthyl

Optically active 3,3′‐dimethyl‐2,2′‐diamino‐1,1′‐binaphthyl (DM‐DABN) and 3,3′‐dimethyl‐2‐amino‐2′‐hydroxybinaphthyl (DM‐NOBIN) derivatives were synthesized by Cu‐(?)‐sparteine complex‐catalyzed enantioselective homo‐ and hetero‐coupling of 2‐naphthylamine, respectively. The difference in enantioselectivity was observed by changing the concentration of oxygen. Chirality, 2010. © 2009 Wiley‐Liss, Inc.     

Synthesis of enantiomers of exo‐2‐norbornyl‐N‐n‐butylcarbamate and endo‐2‐norbornyl‐N‐n‐butylcarbamate for stereoselective inhibition of acetylcholinesterase

The acetylcholinesterase inhibition by enantiomers of exo‐ and endo‐2‐norbornyl‐N‐n‐butylcarbamates shows high stereoselelectivity. For the acetylcholinesterase inhibitions by (R)‐(+)‐ and (S)‐(?)‐exo‐2‐norbornyl‐N‐n‐butylcarbamates, the R‐enantiomer is more potent than the S‐enantiomer. But, for the acetylcholinesterase inhibitions by (R)‐(+)‐ and (S)‐(?)‐endo‐2‐norbornyl‐N‐n‐butylcarbamates, the S‐enantiomer is more potent than the R‐enantiomer. Optically pure (R)‐(+)‐exo‐, (S)‐(?)‐exo‐, (R)‐(+)‐endo‐, and (S)‐(?)‐endo‐2‐norbornyl‐N‐n‐butylcarbamates are synthesized from condensations of optically pure (R)‐(+)‐exo‐, (S)‐(?)‐exo‐, (R)‐(+)‐endo‐, and (S)‐(?)‐endo‐2‐norborneols with n‐butyl isocyanate, respectively. Optically pure norborneols are obtained from kinetic resolutions of their racemic esters by lipase catalysis in organic solvent. Chirality 2010. © 2009 Wiley‐Liss, Inc.     

Whole‐cell biocatalytic of Bacillus cereus WZZ006 strain to synthesis of indoxacarb intermediate: (S)‐5‐Chloro‐1‐oxo‐2,3‐dihydro‐2‐hydroxy‐1H‐indene‐2‐carboxylic acid methyl ester

In this study, a newly isolated strain screened from the indoxacarb‐rich agricultural soils, Bacillus cereus WZZ006, has a high stereoselectivity to racemic substrate 5‐chloro‐1‐oxo‐2,3‐dihydro‐2‐hydroxy‐1H‐indene‐2‐carboxylic acid methyl ester. (S)‐5‐chloro‐1‐oxo‐2,3‐dihydro‐2‐hydroxy‐1H‐indene‐2‐carboxylic acid methyl ester was obtained by bio‐enzymatic resolution. After the 36‐hour hydrolysis in 50‐mM racemic substrate under the optimized reaction conditions, the e.e._s was up to 93.0% and the conversion was nearly 53.0% with the E being 35.0. Therefore, B cereus WZZ006 performed high‐level ability to produce (S)‐5‐chloro‐1‐oxo‐2,3‐dihydro‐2‐hydroxy‐1H‐indene‐2‐carboxylic acid methyl ester. This study demonstrates a new biocatalytic process route for preparing the indoxacarb chiral intermediates and provides a theoretical basis for the application of new insecticides in agricultural production.     

Synthesis and Evaluation of Anticonvulsant Activity of Some Schiff Bases of 7‐Amino‐1,3‐dihydro‐2H‐1,4‐benzodiazepin‐2‐one

A variety of 1,3‐dihydro‐2H‐1,4‐benzodiazepin‐2‐one azomethines and 1,3‐dihydro‐2H‐1,4‐benzodiazepin‐2‐one benzamide were prepared, characterized and evaluated for the anticonvulsant activity in the rat using picrotoxin‐induced seizure model. The prepared 1,3‐dihydro‐2H‐1,4‐benzodiazepin‐2‐one azomethine derivatives emerged potentially anticonvulsant molecular scaffolds exemplified by compounds, 7‐{(E)‐[(4‐nitrophenyl)methylidene]amino}‐5‐phenyl‐1,3‐dihydro‐2H‐1,4‐benzodiazepin‐2‐one, 7‐[(E)‐{[4‐(dimethylamino)phenyl]methylidene}amino]‐5‐phenyl‐1,3‐dihydro‐2H‐1,4‐benzodiazepin‐2‐one, 7‐{(E)‐[(4‐bromo‐2,6‐difluorophenyl)methylidene]amino}‐5‐phenyl‐1,3‐dihydro‐2H‐1,4‐benzodiazepin‐2‐one and 7‐[(E)‐{[3‐(4‐fluorophenyl)‐1‐phenyl‐1H‐pyrazol‐4‐yl]methylidene}amino]‐5‐phenyl‐1,3‐dihydro‐2H‐1,4‐benzodiazepin‐2‐one. All these four compounds have shown substantial decrease in the wet dog shake numbers and grade of convulsions with respect to the standard drug diazepam. The most active compound, 7‐[(E)‐{[4‐(dimethylamino)phenyl]methylidene}amino]‐5‐phenyl‐1,3‐dihydro‐2H‐1,4‐benzodiazepin‐2‐one, exhibited 74 % protection against convulsion which was higher than the standard drug diazepam. Furthermore, to identify the binding mode of the interaction amongst the target analogs and binding site of the benzodiazepine receptor, molecular docking study and molecular dynamic simulation were carried out. Additionally, in silico pharmacokinetic and toxicity predictions of target compounds were carried out using AdmetSAR tool. Results of ADMET studies suggest that the pharmacokinetic parameters of all the target compounds were within the acceptable range to become a potential drug candidate as antiepileptic agents.     

Synthesis of 8‐Substituted 2′‐Deoxyisoguanosines via Unprotected 8‐Brominated 2‐Amino‐2′‐deoxyadenosine

A variety of applications of 8‐alkynylated nucleosides has prompted the synthesis of new purine analogues. Bromination of unprotected 2‐amino‐2′‐deoxyadenosine with Br₂/AcOH/AcONa gives 2‐amino‐8‐bromo‐2′‐deoxyadenosine (87%). The brominated derivative is converted to 8‐alkynylated 2‐amino‐2′‐deoxyadenosines by palladium‐catalyzed Sonogashira cross‐coupling reaction via microwave assistance (81 – 95%). The resulting compounds are further transformed to 8‐alkynylated 2′‐deoxyisoguanosines (52 – 70%). The physical properties of new compounds are investigated.     

Novel renin inhibitors containing derivatives of N‐alkylleucyl‐β‐hydroxy‐γ‐amino acids

In search for new drugs lowering arterial blood pressure, which could be applied in anti‐hypertensive therapy, research concerning agents blocking of renin‐angiotensin‐aldosteron system has been conducted. Despite many years of research conducted at many research centers around the world, aliskiren is the only one renin inhibitor, which is used up to now. Four novel potential renin inhibitors, having structure based on the peptide fragment 8–13 of human angiotensinogen, a natural substrate for renin, were designed and synthesized. All these inhibitors contain unnatural moieties that are derivatives of N‐methylleucyl‐β‐hydroxy‐γ‐amino acids at the P₂‐P₁' position: 4‐[N‐(N‐methylleucyl)‐amino]‐3‐hydroxy‐7‐(3‐nitroguanidino)‐heptanoic acid (AHGHA), 4‐[N‐(N‐methylleucyl)‐amino]‐3‐hydroxy‐5‐phenyl‐pentanoic acid (AHPPA) or 4‐[N‐(N‐methylleucyl)‐amino]‐8‐benzyloxycarbonylamino‐3‐hydroxyoctanoic acid (AAHOA). The previously listed synthetic β‐hydroxy‐γ‐amino acids constitute pseudodipeptidic units that correspond to the P₁‐P₁' position of the inhibitor molecule. An unnatural amino acid, 4‐methoxyphenylalanin (Phe(4‐OMe)), was introduced at the P₃ position of the obtained compounds. Three of these compounds contain isoamylamide of 6‐aminohexanoic acid (ε‐Ahx‐Iaa) at the P₂'‐P₃' position. The proposed modifications of the selected human angiotensinogen fragment are intended to increase bioactivity, bioavailability, and stability of the inhibitor molecule in body fluids and tissues. The inhibitor Boc‐Phe(4‐OMe)‐MeLeu‐AHGHA‐OEt was obtained in the form of an ethyl ester. The hydrophobicity coefficient, expressed as log P varied between 3.95 and 8.17. In vitro renin inhibitory activity of all obtained compounds was contained within the range 10^?6‐10^?9 M. The compound Boc‐Phe(4‐OMe)‐MeLeu‐AHPPA‐Ahx‐Iaa proved to be the most active (IC₅₀ = 1.05 × 10^?9 M). The compounds Boc‐Phe(4‐OMe)‐MeLeu‐AHGHA‐Ahx‐Iaa and Boc‐Phe(4‐OMe)‐MeLeu‐AHPPA‐Ahx‐Iaa are resistant to chymotrypsin. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.     

Synthesis and optical resolution of 1‐[(3‐carboxy‐1,1′‐biphenyl)‐2‐yl]‐1H‐pyrrole‐2‐carboxylic acid

Site selective mono‐ and dimetalation methods have been developed for the functionalization of 1‐[(1,1′‐biphenyl)‐2‐yl]‐1H‐pyrrole. Optical resolution of the prepared 1‐[(3‐carboxy‐1,1′‐biphenyl)‐2‐yl]pyrrole‐2‐carboxylic acid provided new atropisomeric 1‐arylpyrrole derivatives. The absolute configuration of the pure dicarboxylic acid enantiomers was determined by single crystal X‐ray diffraction and CD spectroscopy. Chirality 2009. © 2009 Wiley‐Liss, Inc.     

Enantioselective resolution of 4‐chloromandelic acid by liquid–liquid extraction using 2‐chloro‐N‐carbobenzyloxy‐L‐amino acid

A liquid–liquid extraction resolution of 4‐chloro‐mandelic acid (4‐ClMA) was studied by using 2‐chloro‐N‐carbobenzyloxy‐L‐amino acid (2‐Cl‐Z‐AA) as a chiral extractant. Important factors affecting the extraction efficiency were investigated, including the type of chiral extractant, pH value of aqueous phase, initial concentration of chiral extractant in organic phase, initial concentration of 4‐ClMA in aqueous phase, and resolution temperature. It was observed that the concentration of (R)‐4‐ClMA was much higher than that of (S)‐4‐ClMA in organic phase due to a higher stability of the complex formed between (R)‐4‐ClMA and 2‐Cl‐Z‐AA. A separation factor (α) of 3.05 was obtained at 0.02 mol/L 2‐Cl‐Z‐Valine dissolved in dichloromethane, pH of 2.0, concentration of 4‐ClMA of 0.11 mmol/Land T of 296.7K.     

Application of NMR spectroscopy for assignment of the absolute configuration of 8‐tert‐butyl‐2‐hydroxy‐7‐methoxy‐8‐methyl‐9‐oxa‐6‐azaspiro[4.5]dec‐6‐en‐10‐one

In order to assign the absolute configurations of 8‐tert‐butyl‐2‐hydroxy‐7‐methoxy‐8‐methyl‐9‐oxa‐6‐azaspiro[4.5]dec‐6‐en‐10‐one ( 2a , 2b ), their esters ( 5a , 5b , 5c , 5d ) with (R)‐ or (S)‐2‐methoxyphenylacetic acid ( 4a , 4b ) have been synthesized. The absolute configurations of these compounds have been determined on the basis of NOESY correlations between the protons of the tert‐butyl group and the cyclopentane fragment of the molecules. The crucial part of this analysis was assignment of the absolute configuration at C‐5. Additionally, by calculation of the chemical shift anisotropy, δ^RS, for the relevant protons, it was also possible to confirm the absolute configurations at the C‐2 centres of compounds 2a , 2b and 5a , 5b , 5c , 5d . Chirality, 25:422–426, 2013.© 2013 Wiley Periodicals, Inc.     

The diversion of 2‐C‐methyl‐d‐erythritol‐2,4‐cyclodiphosphate from the 2‐C‐methyl‐d‐erythritol 4‐phosphate pathway to hemiterpene glycosides mediates stress responses in Arabidopsis thaliana

2‐C‐Methyl‐d ‐erythritol‐2,4‐cyclodiphosphate (MEcDP) is an intermediate of the plastid‐localized 2‐C‐methyl‐d ‐erythritol‐4‐phosphate (MEP) pathway which supplies isoprenoid precursors for photosynthetic pigments, redox co‐factor side chains, plant volatiles, and phytohormones. The Arabidopsis hds‐3 mutant, defective in the 1‐hydroxy‐2‐methyl‐2‐(E)‐butenyl‐4‐diphosphate synthase step of the MEP pathway, accumulates its substrate MEcDP as well as the free tetraol 2‐C‐methyl‐d ‐erythritol (ME) and glucosylated ME metabolites, a metabolic diversion also occurring in wild type plants. MEcDP dephosphorylation to the free tetraol precedes glucosylation, a process which likely takes place in the cytosol. Other MEP pathway intermediates were not affected in hds‐3. Isotopic labeling, dark treatment, and inhibitor studies indicate that a second pool of MEcDP metabolically isolated from the main pathway is the source of a signal which activates salicylic acid induced defense responses before its conversion to hemiterpene glycosides. The hds‐3 mutant also showed enhanced resistance to the phloem‐feeding aphid Brevicoryne brassicae due to its constitutively activated defense response. However, this MEcDP‐mediated defense response is developmentally dependent and is repressed in emerging seedlings. MEcDP and ME exogenously applied to adult leaves mimics many of the gene induction effects seen in the hds‐3 mutant. In conclusion, we have identified a metabolic shunt from the central MEP pathway that diverts MEcDP to hemiterpene glycosides via ME, a process linked to balancing plant responses to biotic stress.     

Automated docking studies provide insights into molecular determinants of ligand recognition by N‐acetyl‐1‐d‐myo‐inosityl‐2‐amino‐2‐deoxy‐α‐d‐glucopyranoside deacetylase (MshB)

The metal‐dependent deacetylase N‐acetyl‐1‐d ‐myo‐inosityl‐2‐amino‐2‐deoxy‐α‐d ‐glucopyranoside deacetylase (MshB) catalyzes the deacetylation of N‐acetyl‐1‐d ‐myo‐inosityl‐2‐amino‐2‐deoxy‐α‐d ‐glucopyranoside (GlcNAc‐Ins), the committed step in mycothiol (MSH) biosynthesis. MSH is the thiol redox buffer used by mycobacteria to protect against oxidative damage and is involved in the detoxification of xenobiotics. As such, MshB is a target for the discovery of new drugs to treat tuberculosis (TB). While MshB substrate specificity and inhibitor activity have been probed extensively using enzyme kinetics, information regarding the molecular basis for the observed differences in substrate specificity and inhibitor activity is lacking. Herein we begin to examine the molecular determinants of MshB substrate specificity using automated docking studies with a set of known MshB substrates. Results from these studies offer insights into molecular recognition by MshB via identification of side chains and dynamic loops that may play roles in ligand binding. Additionally, results from these studies suggest that a hydrophobic cavity adjacent to the active site may be one important determinant of MshB substrate specificity. Importantly, this hydrophobic cavity may be advantageous for the design of MshB inhibitors with high affinity and specificity as potential TB drugs. © 2013 Wiley Periodicals, Inc. Biopolymers 101: 406–417, 2014.     

Substituent effects on chiral resolutions of derivatized 1‐phenylalkylamines by heptakis(2,3‐di‐O‐methyl‐6‐O‐tert‐butyldimethylsilyl)‐β‐cyclodextrin GC stationary phase

Chiral resolutions of trifluoroacetyl‐derivatized 1‐phenylalkylamines with different type and position of substituent were investigated by capillary gas chromatography by using heptakis(2,3‐di‐O‐methyl‐6‐O‐tert‐butyldimethylsilyl)‐β‐cyclodextrin diluted in OV‐1701 as a chiral stationary phase. The influence of column temperature on retention and enantioselectivity was examined. All enantiomers of meta‐substituted analytes as well as fluoro‐substituted analytes could be resolved. Temperature had a favorable influence on enantioselectivity for small amines with substituents at the ortho‐position. The type of substituent at the stereogenic center of amines also had a crucial effect as the ethyl group led to poor enantioseparation. Among all analytes studied, trifluoroacetyl‐derivatized 1‐(2′‐fluorophenyl)ethylamine exhibited baseline resolution with the shortest analysis time.     

5α‐Androst‐16‐en‐3α‐ol β‐D‐Glucuronide,Precursor of 5α‐Androst‐16‐en‐3α‐ol in Human Sweat

5α‐Androst‐16‐en‐3α‐ol (α‐androstenol) is an important contributor to human axilla sweat odor. It is assumed that α‐andostenol is excreted from the apocrine glands via a H₂O‐soluble conjugate, and this precursor was formally characterized in this study for the first time in human sweat. The possible H₂O‐soluble precursors, sulfate and glucuronide derivatives, were synthesized as analytical standards, i.e., α‐androstenol, β‐androstenol sulfates, 5α‐androsta‐5,16‐dien‐3β‐ol (β‐androstadienol) sulfate, α‐androstenol β‐glucuronide, α‐androstenol α‐glucuronide, β‐androstadienol β‐glucuronide, and α‐androstenol β‐glucuronide furanose. The occurrence of α‐androstenol β‐glucuronide was established by ultra performance liquid chromatography (UPLC)/MS (heated electrospray ionization (HESI)) in negative‐ion mode in pooled human sweat, containing eccrine and apocrine secretions and collected from 25 female and 24 male underarms. Its concentration was of 79 ng/ml in female secretions and 241 ng/ml in male secretions. The release of α‐androstenol was observed after incubation of the sterile human sweat or α‐androstenol β‐glucuronide with a commercial glucuronidase enzyme, the urine‐isolated bacteria Streptococcus agalactiae, and the skin bacteria Staphylococcus warneri DSM 20316, Staphylococcus haemolyticus DSM 20263, and Propionibacterium acnes ATCC 6919, reported to have β‐glucuronidase activities. We demonstrated that if α‐ and β‐androstenols and androstadienol sulfates were present in human sweat, their concentrations would be too low to be considered as potential precursors of malodors; therefore, the H₂O‐soluble precursor of α‐androstenol in apocrine secretion should be a β‐glucuronide.     

Anticonvulsant Activity of Enantiomeric N‐trans‐Cinnamoyl Derivatives of 2‐Aminopropan‐1‐ols and 2‐Aminobutan‐1‐ols

Epilepsy, one of the most frequent neurological disorders, is still insufficiently treated in about 30% of patients. As a consequence, identification of novel anticonvulsant agents is an important issue in medicinal chemistry. In the present article we report synthesis, physicochemical, and pharmacological evaluation of N‐trans‐cinnamoyl derivatives of R and S‐2‐aminopropan‐1‐ol, as well as R and S‐2‐aminobutan‐1‐ol. The structures were confirmed by spectroscopy and for derivatives of 2‐aminopropan‐1‐ols the configuration was evaluated by means of crystallography. The investigated compounds were tested in rodent models of seizures: maximal electroshock (MES) and subcutaneous pentetrazol test (scPTZ), and also in a rodent model of epileptogenesis: pilocarpine‐induced status prevention. Additionally, derivatives of 2‐aminopropan‐1‐ols were tested in benzodiazepine‐resistant electrographic status epilepticus rat model as well as in vitro for inhibition of isoenzymes of cytochrome P450. All of the tested compounds showed promising anticonvulsant activity in MES. For R(–)‐(2E)‐N‐(1‐hydroxypropan‐2‐yl)‐3‐phenylprop‐2‐enamide pharmacological parameters were found as follows: ED₅₀ = 76.7 (68.2–81.3) mg/kg (MES, mice i.p., time = 0.5 h), ED₅₀ = 127.2 (102.1–157.9) mg/kg (scPTZ, mice i.p., time = 0.25 h), TD₅₀ = 208.3 (151.4–230.6) mg/kg (rotarod, mice i.p., time = 0.25 h). Evaluation in pilocarpine status prevention proved that all of the reported compounds reduced spontaneous seizure activity and act as antiepileptogenic agents. Both enantiomers of 2‐aminopropan‐1‐ols did not influence cytochrome P450 isoenzymes activity in vitro and are likely not to interact with CYP substrates in vivo. Chirality 28:482–488, 2016. © 2016 Wiley Periodicals, Inc.     

The Ku‐dependent non‐homologous end‐joining pathway contributes to low‐dose radiation‐stimulated cell survival

Low‐dose (≤0.1 Gy) radiation‐induced adaptive responses could protect cells from high‐challenge dose radiation‐induced killing. The protective role is believed to promote the repair of DNA double‐strand breaks (DSBs) that are a severe threat to cell survival. However, it remains unclear which repair pathway, homologous recombination repair (HRR) or non‐homologous end‐joining (NHEJ), is promoted by low‐dose radiation. To address this question, we examined the effects of low‐dose (0.1 Gy) on high‐challenge dose (2–4 Gy) induced killing in NHEJ‐ or HRR‐deficient cell lines. We showed that 0.1 Gy reduced the high‐dose radiation‐induced killing for wild‐type or HRR‐deficient cells, but enhanced the killing for NHEJ‐deficient cells. Interestingly, low‐dose radiation also enhanced the killing for wild‐type cells exposed to high‐challenge dose radiation with high‐linear energy transfer (LET). Because it is known that high‐LET radiation induces an inefficient NHEJ, these results support that the low‐dose radiation‐stimulated protective role in reducing high‐challenge dose (low‐LET)‐induced cell killing might depend on NHEJ. In addition, we showed that low‐dose radiation activated the DNA‐PK catalytic subunit (DNA‐PKcs) and the inhibitor of DNA‐PKcs destroyed the low‐dose radiation‐induced protective role. These results suggest that low‐dose radiation might promote NHEJ through the stimulation of DNA‐PKcs activity and; therefore, increase the resistance of cells to high‐challenge dose radiation‐induced killing. J. Cell. Physiol. 226: 369–374, 2011. © 2010 Wiley‐Liss, Inc.     

The crystal structure of Z‐Gly‐Aib‐Gly‐Aib‐OtBu

The synthetic peptide Z‐Gly‐Aib‐Gly‐Aib‐OtBu was dissolved in methanol and crystallized in a mixture of ethyl acetate and petroleum ether. The crystals belong to the centrosymmetric space group P4/n that is observed less than 0.3% in the Cambridge Structural Database. The first Gly residue assumes a semi‐extended conformation (φ ±62°, ψ ?131°). The right‐handed peptide folds in two consecutive β‐turns of type II' and type I or an incipient 3₁₀‐helix, and the left‐handed counterpart folds accordingly in the opposite configuration. In the crystal lattice, one molecule is linked to four neighbors in the ab‐plane via hydrogen bonds. These bonds form a continuous network of left‐ and right‐handed molecules. The successive ab‐planes stack via apolar contacts in the c‐direction. An ethyl acetate molecule is situated on and close to the fourfold axis. Copyright © 2015 European Peptide Society and John Wiley & Sons, Ltd.     

Epigallocatechin‐3‐O‐gallate up‐regulates microRNA‐199a‐3p expression by down‐regulating the expression of cyclooxygenase‐2 in stimulated human osteoarthritis chondrocytes

Osteoarthritis (OA) is a most common form of arthritis worldwide leading to significant disability. MicroRNAs (miRNAs) are non‐coding RNAs involved in various aspects of cartilage development, homoeostasis and pathology. Several miRNAs have been identified which have shown to regulate expression of target genes relevant to OA pathogenesis such as matrix metalloproteinase (MMP)‐13, cyclooxygenase (COX)‐2, etc. Epigallocatechin‐3‐O‐gallate (EGCG), the most abundant and active polyphenol in green tea, has been reported to have anti‐arthritic effects, however, the role of EGCG in the regulation of miRNAs has not been investigated in OA. Here, we showed that EGCG inhibits COX‐2 mRNA/protein expression or prostaglandin E₂ (PGE₂) production via up‐regulating microRNA hsa‐miR‐199a‐3p expression in interleukin (IL)‐1β‐stimulated human OA chondrocytes. This negative co‐regulation of hsa‐miR‐199a‐3p and COX‐2 by EGCG was confirmed by transfection of OA chondrocytes with anti‐miR‐199a‐3p. Transfection of OA chondrocytes with anti‐miR‐199a‐3p significantly enhanced COX‐2 expression and PGE₂ production (P < 0.001), while EGCG treatment significantly inhibited anti‐miR‐199a‐3p transfection‐induced COX‐2 expression or PGE₂ production in a dose‐dependent manner. These results were further re‐validated by co‐treatment of these transfection OA chondrocytes with IL‐1β and EGCG. EGCG treatment consistently up‐regulated the IL‐1β‐decreased hsa‐miR‐199a‐3p expression (P < 0.05) and significantly inhibited the IL‐1β‐induced COX‐2 expression/PGE₂ production (P < 0.05) in OA chondrocytes transfected with anti‐hsa‐miR‐199a‐3p. Taken together, these results clearly indicate that EGCG inhibits COX‐2 expression/PGE₂ production via up‐regulation of hsa‐miR‐199a‐3p expression. These novel pharmacological actions of EGCG on IL‐1β‐stimulated human OA chondrocytes provide new suggestions that EGCG or EGCG‐derived compounds inhibit cartilage breakdown or pain by up‐regulating the expression of microRNAs in human chondrocytes.     

Dodecyl α‐L‐Rhamnopyranosyl‐(1→2)‐β‐D‐fucopyranoside Derivatives from the Glandular Trichome Exudate of Erodium pelargoniflorum

Chemical investigation of the glandular trichome exudate of Erodium pelargoniflorum (Geraniaceae) led to the isolation of two dodecyl disaccharide derivatives, named pelargoside A1 and pelargoside B1 ( 1 and 2 , resp.). The structures of 1 and 2 were determined as dodecyl 4‐O‐acetyl‐α‐L ‐rhamnopyranosyl‐(1→2)‐4‐O‐acetyl‐β‐D ‐fucopyranoside and dodecyl 3,4‐di‐O‐acetyl‐α‐L ‐rhamnopyranosyl‐(1→2)‐4‐O‐acetyl‐β‐D ‐fucopyranoside, respectively, by spectroscopic studies, including 2D‐NMR, and chemical transformations. In addition, undecyl, tridecyl, and tetradecyl homologs of 1 and 2 , named pelargosides A2–A4 and pelargosides B2–B4, were also characterized as minor constituents of the exudate.