Clerodendrumic Acid,a New Triterpenoid from Clerodendrum glabrum (Verbenaceae), and Antimicrobial Activities of Fractions and Constituents

One new triterpenoid, (3β,11α,19β)‐3‐(butanoyloxy)‐11‐hydroxytaraxast‐20(30)‐ene‐23,28‐dioic acid (clerodendrumic acid; 1 ) was isolated from the hexane extract of the leaves of Clerodendrum glabrum var. glabrum along with heptadecanoic acid ( 2 ). The structure of the new compound was elucidated by interpretation of its NMR (1D and 2D), MS, and IR data. Combined fractions C and D from the column chromatography of the hexane extract exhibited significant antifungal activities (average MIC of 0.10 mg/ml) against Candida albicans and Cryptococcus neoformans. C. albicans was relatively resistant to clerodendrumic acid ( 1 ; MIC 125 μg/ml) and was resistant to heptadecanoic acid ( 2 ; MIC 188 μg/ml). Both compounds had low antibacterial activities against two Gram‐positive and two Gram‐negative bacteria with average MIC values of 157 and 172 μg/ml, respectively. Compounds 1 and 2 were relatively nontoxic against monkey kidney Vero cells in vitro with IC₅₀ values of 202.6 and 108.4 μg/ml, respectively.     

Bauhinoxepins A and B: New Antimycobacterial Dibenzo[b,f]oxepins from Bauhinia saccocalyx

Two new antimycobacterial dibenzo[b,f]oxepins, bauhinoxepins A (=3,3,5‐trimethylbenzo[b]pyrano[g][1]benzoxepin‐6,11‐diol; 1 ) and B (=6‐methoxy‐7‐methyl‐2‐(3‐methylbut‐2‐enyl)dibenzo[b,f]oxepine‐1,8‐diol; 2 ), were isolated from the roots of Bauhinia saccocalyx, and their structures were elucidated by analysis of spectroscopic data. Bauhinoxepins A and B exhibited antimycobacterial activities with respective minimum‐inhibitory concentrations (MIC) of 6.25 and 12.5 μg/ml. They were inactive (at 20 μg/ml) against the malarial parasite, and also inactive (at 20 μg/ml) towards the Vero, KB, and BC cell lines.     

Studies on Antifungal Agents. Part 22. 3-aryl-5-[(aryloxy)alkyl]-3-[(1H-imidazol-1-yl)methyl]-2-methylisoxazolidines and related derivatives

The synthesis and antifungal activity of a novel series of 3-aryl-5-[(aryloxy)alkyl]-3-[(1H-imidazol-1-yl)-methyl]-2-methylisoxazolidines and related compounds, are discussed. The synthesis of the title compounds was accomplished via a 1,3-dipolar cycloaddition of α-substituted ketonitrones with l-alkenyl phenyl ethers (Scheme 2 and 3). The compounds were evaluated for in vitro antifungal activity in solid agar cultures against a broad variety of yeast and systemic mycoses and dermatophytes. While antifungal activity was evident throughout the series, in general, derivatives having halogen atom(s) in either or both aryl rings demonstrated the highest potency, especially against Trichophyton rubrum and Candida albicans. The dichloro analog 20 (PR 967-248) was found to possess the most useful activity. Its minimum inhibitory concentration (MIC) values ranged between 0.2 and 2.0 μg/ml, as compared to 0.2–20.0 μg/ml for the standard drug ketoconazole (4).     

Sesquiterpenoids from the Root Bark of Acanthopanax leucorrhizus and Their Biological Activities

Three furoeremophilane‐type sesquiterpenoids, including one new, 1α‐acetoxy‐6β‐(benzoyloxy)‐10β‐hydroxy‐9‐oxofuroeremophilane ( 1 ), and two known, 1β,6β‐diacetoxy‐9‐oxofuroeremophilane ( 2 ) and (6α)‐furoeremophilan‐14,6‐olide ( 3 ), were isolated from the root bark of Acanthopanax leucorrhizus from China. Their structures were elucidated on the basis of comprehensive spectroscopic analyses, including IR, HR‐ESI‐MS, 1D‐ and 2D‐NMR experiments. A preliminary bioassay revealed that compound 1 exhibits weak cytotoxicities against the human tumor cell lines MCF‐7 and SMMC‐7721 with the IC₅₀ values of 75.12±1.69 and 168.36±2.01 μg/ml, respectively. Compound 1 and 2 showed moderate activities against Escherichia coli with the MIC values of 32 and 64 μg/ml, respectively.     

Oxepine‐Containing Diketopiperazine Alkaloids from the Algal‐Derived Endophytic Fungus Paecilomyces variotii EN‐291

Two new oxepine‐containing diketopiperazine‐type alkaloids, varioloids A and B ( 1 and 2 , resp.), were isolated from the algal‐derived fungus Paecilomyces variotii EN‐291. The structures and absolute configurations were determined by detailed interpretation of 1D‐ and 2D‐NMR spectroscopic data and by analysis of acidic hydrolysates. Compounds 1 and 2 exhibited potent activity against the plant‐pathogenic fungus Fusarium graminearum with MIC values of 8 and 4 μg/ml, respectively.     

Two Unusual Phenolic Substances and One New Xanthone from Hypericum sampsonii

Sampsone A ( 1 ), a novel prenylated aromatic lactone, and sampsone B ( 2 ), an unusual dihydrodibenzodioxinone, together with sampsone C ( 3 ), a new xanthone, were isolated from the aerial parts of Hypericum sampsonii. Their structures were determined by spectroscopic methods which were mainly 1D‐ and 2D‐NMR techniques, and the structure of sampsone B ( 2 ) was also confirmed by X‐ray crystallographic analysis. All of these compounds were evaluated for in vitro antibacterial activity against methicillin‐resistant Staphylococcus aureus (MRSA). Only sampsone A showed moderate antibacterial activities at a minimum inhibitory concentration (MIC) of 32 μg/ml.     

Bioactive Trichothecenes Produced by the Myrothecium sp. QB‐1

Three new simple trichothecenes, 15‐acetyltrichoverrol B ( 3 ), 13′‐acetyltrichoverrin B ( 5 ), and 6′‐dehydroxytrichoverrin B ( 6 ), along with five known trichothecenes trichodermadienediol B ( 1 ), trichoverrol B ( 2 ), trichoverrin B ( 4 ), and roridins A ( 7 ) and D ( 8 ), have been isolated from the liquid culture of Myrothecium roridum (strain no. QB‐1). The structures of the new compounds were established by comprehensive analysis of 1D‐ and 2D‐NMR data. All the compounds were evaluated for antifungal activity, only compounds 7 and 8 showed significant antifungal activity against the tested fungi (MIC ranged from 10 to 5 μg/ml).     

Ultrasound‐Assisted Synthesis of 3‐(Arylamino)‐1‐ferrocenylpropan‐1‐ones

A successful aza‐Michael addition of arylamines to a conjugated enone, acryloylferrocene, has been achieved by ultrasonic irradiation of the mixture of these reactants and the catalyst, i.e., montmorillonite K‐10. This solvent‐free reaction, yielding ferrocene containing Mannich bases, 3‐(arylamino)‐1‐ferrocenylpropan‐1‐ones, considered as valuable precursors in organic synthesis, has been performed by using a simple ultrasonic cleaner. Among 17 synthesized β‐amino ketones, three were new ones, and these were fully characterized by spectroscopic means. X‐Ray crystallographic analysis of three of these crystalline products enabled the insight into the conformational details of these compounds. All compounds were evaluated for their antibacterial activities against six Gram‐positive and five Gram‐negative strains in a microdilution assay. The observed promising antibacterial activity (with a MIC value of 25 μg/ml (ca. 0.07 μmol/ml) as the best result for almost all tested compounds against Micrococcus flavus) seems not only to be compound but also bacterial species‐specific.     

Identification of Five New Minor Constituents from the Whole Plant of Amischotolype hispida

Bioassay‐guided fractionation of the active AcOEt‐soluble layer from the whole plant of Amischotolype hispida resulted in the isolation of four new compounds, i.e., amisbenzoic acid ( 1 ), one butenolide derivative, amisnolide ( 2 ), one chlorin analog, amisphytin ( 3 ), one lignan, amislignol ( 4 ), and one metabolite isolated for the first time from nature, (?)‐glaberide I ( 5 ), along with 20 known compounds, 6 – 25 . Their structures were elucidated on the basis of UV, IR, 1D‐ and 2D‐NMR (¹H,¹H‐COSY, DEPT, HSQC, HMBC), as well as HR‐ESI‐MS, analyses. Among these isolates, palmitic acid ( 13 ) showed an antimycobacterial activity with an MIC value of 20.0 μg/ml against Mycobacterium tuberculosis H37Rv.     

Synthesis,Configuration, and Antimicrobial Properties of Novel Substituted and Cyclized ‘2′,3″‐Thiazachalcones’

Nine new thiazachalcone‐based drugs, compounds 1 – 9 , were prepared and fully characterized. The configurations of the photochemical‐dimerization products 7 – 9 were rationalized by semi‐empirical calculations. Both the experimental data and the theoretical calculations showed that the δ‐truxinic acid type dimer is the most stable isomer of all. All compounds were tested for their antibacterial and antifungal activities. The N‐alkylated congeners 4 – 6 showed strong antimicrobial activities against various bacteria and a yeast‐like fungus. The MIC and MBC values were as low as 0.1 μg/ml. All the compounds were active against the Gram‐positive bacterium Staphylococcus aureus.     

Biofabrication of iron oxide nanoparticles by leaf extract of Rhamnus virgata: Characterization and evaluation of cytotoxic,antimicrobial and antioxidant potentials

In the present study, plant‐mediated synthesis of iron oxide nanoparticles (IONPs) using leaves extract of Rhamnus virgata (Roxb.) as a potential stabilizing, reducing and chelating agent is reported. The biogenic IONPs are extensively characterized for their physical and biological properties. The morphology, structure and physicochemical properties of biogenic IONPs were characterized using ultraviolet spectroscopy, X‐ray diffraction, Fourier transform‐infrared analysis, scanning electron microscopy, energy‐dispersive spectroscopy, transmission electron microscopy, Raman spectroscopy and dynamic light scattering. The Scherrer equation deduced a mean crystallite size of ~20 nm for IONPs. Detailed in vitro biological activities revealed significant therapeutic potentials for IONPs. Potential antibacterial and antifungal activities are reported for IONPs. Bioinspired IONPs have shown potential results against HepG2 cells (IC₅₀: 13.47 μg/ml). Dose‐dependent cytotoxicity assays were revealed against Leishmania tropica (KMH₂₃) promastigotes (IC₅₀: 8.08 μg/ml) and amastigotes (IC₅₀: 20.82 μg/ml) using different concentrations of IONPs (1–200 μg/ml). The cytotoxic activity was also studied using brine shrimps, and their IC₅₀ value was calculated as 32.41 μg/ml. Significant antioxidant [TAC (51.4%), DPPH (79.4%) and total reducing power (62%)], protein kinase and alpha amylase inhibition assays were revealed. The biocompatibility assays using red blood cells (> 200 μg/ml) and macrophages (> 200 μg/ml) confirmed the biosafe nature of IONPs. In conclusion, bioinspired IONPs have shown potential biological applications and should be subjected to further research work to develop their nano‐pharmacological relevance in biomedical applications.     

Stereoselective Synthesis,Characterization, and Antibacterial Activities of Novel Isosteviol Derivatives with D‐Ring Modification

Considerable interests have been attracted by isosteviol and its derivatives because of their large variety of bioactivities. In this project, a series of novel 15‐ and 16‐substituted isosteviol derivatives were stereoselectively prepared by means of functional interconversions in ring D of the tetracyclic diterpene isosteviol. All compounds synthesized were characterized by analysis of NMR, IR, HR‐MS data, and the configurations of 33 and 37 were confirmed by X‐ray crystallographic analysis. The antibacterial activities in vitro of these isosteviol derivatives were investigated; the synthetic compounds were more active against Gram‐positive than Gram‐negative bacteria, and were especially active against Bacillus subtilis. Among them, compound 27 (MIC=1.56 μg/ml) exhibited the highest antibacterial activity and thus may be exploitable as a lead compound for the development of potent antibacterial agents.     

Aalysis of the fatty acid composition of the lipid classes in human blood serum under normal diet and when supplemented with fish oil

Total lipids have been extracted from human serum with chloroform–methanol 2:1 (v/v) and separated into individual classes by TLC. After transesterification the fatty acid methyl esters were analyzed by capillary gas chromatography on an FFAP column. The quantitation of ω-3 fatty acids has been performed using internal and external standards. Internal lipid standards for each lipid class were carried throughout the entire analytical procedure. Under normal diet eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are incorporated into the lipid classes to different extents: cholesterol esters; EPA, 6.5 ± 1.9 γ/ml serum; DHA, 4.3 ± 1.9 μg/ml: phospholipids; EPA, 5.9 ± 2.7 μg/ml; DHA, 31.8 ± 8.1 μg/ml. Fish oil supplementation leads to a 4 to 6-fold rise in EPA and to an approximately 2-fold rise in DHA.     

Development and validation of a simple method for the extraction and quantification of crisaborole in skin layers

Crisaborole is a boron compound recently approved by the US Food and Drug Administration as a 2% ointment for the treatment of mild to moderate atopic dermatitis. This work describes a simple method for the quantification of the drug in the skin layers at the end of in‐vitro permeation experiments. Chromatographic separation was carried out on a reverse‐phase C₁₈ column using a mixture of trifluoroacetic acid 0.05%–acetonitrile (55:45, v/v) as mobile phase, pumped at 1 ml/min. Column temperature was 35°C and UV detection was performed at 250 nm. The method was linear in the range of concentration from 0.06 to 6 μg/ml (R² = 1) and was selective, precise and accurate. Depending on the solvent used, the LOQ ranged from 0.014 to 0.030 μg/ml and the LOD from 0.005 to 0.010 μg/ml. The extraction from all the skin layers was quantitative. The developed method was successfully tested in an in‐vitro permeation study, proving to be an effective tool in the development of new formulations containing crisaborole.     

Antimicrobial Polymers Prepared by Ring‐Opening Metathesis Polymerization: Manipulating Antimicrobial Properties by Organic Counterion and Charge Density Variation

The synthesis and characterization of a series of poly(oxanorbornene)‐based synthetic mimics of antimicrobial peptides (SMAMPs) is presented. In the first part, the effect of different organic counterions on the antimicrobial properties of the SMAMPs was investigated. Unexpectedly, adding hydrophobicity by complete anion exchange did not increase the SMAMPs’ antimicrobial activity. It was found by dye‐leakage studies that this was due to the loss of membrane activity of these polymers caused by the formation of tight ion pairs between the organic counterions and the polymer backbone. In the second part, the effect of molecular charge density on the biological properties of a SMAMP was investigated. The results suggest that, above a certain charge threshold, neither minimum inhibitory concentration (MIC₉₀) nor hemolytic activity (HC₅₀) is greatly affected by adding more cationic groups to the molecule. A SMAMP with an MIC₉₀ of 4 μg mL^?1 against Staphylococcus aureus and a selectivity (=HC₅₀/MIC₉₀) of 650 was discovered, the most selective SMAMP to date.     

Development and validation of a HPLC–UV based method for the extraction and quantification of methotrexate in the skin

An innovative and sensitive HPLC–UV method for the extraction and quantification of methotrexate (MTX) in skin layers was developed and validated. Owing to the physico-chemical characteristics of the drug and the nature of the tissue, it was necessary to use folic acid (FA) as an internal standard for MTX quantification in the dermis. MTX (and FA) analysis was performed on a Phenomenex Jupiter C₁₈ column, using a 50 mm sodium acetate buffer (pH 3.6) and methanol mixture (87:13, v/v) as mobile phase, pumped at 1 ml/min. The absorbance was monitored at 290 nm. The method was selective, linear in the range 0.11–8.49 μg/ml for extraction solvent and 0.05–8.94 μg/ml for pH 7.4 phosphate-buffered saline, precise and accurate, with lower limits of quantitation of 0.11 μg/ml (extraction solvent) and 0.05 μg/ml (pH 7.4 phosphate-buffered saline). The method developed is suitable for the quantification of MTX in skin layers at the end of in vitro permeation experiments; the overall mass balance was 96.5 ± 1.4%, in line with the requirements of the Organisation for Economic Co-operation and Development guideline for the testing of the chemicals (Skin absorption: in vitro method).     

Absorption Spectra of 4f Electron Transitions of Neodymium and Erbium with 8-Hydroxyquinoline-5-sulphonic Acid and Diethylamine Systems and Its Analytical Application

Abstract

In this paper the absorption spectra of 4f electron transitions of the systems of neodymium and erbium with 8-hydroxyquino-line-5-sulphonic acid and diethylamine have been studied by normal and third-derivative spectrophotometry. Their molar absorptivities are 80 l.mol^?1.cm^?1 for neodymium and 65 l.mol^?1.cm^?1 for erbium. Use of the third-derivative spectra, eliminates the interference by other rare earths and increases the sensitivity for Nd and Er. The derivative molar absorptivities are 390 1.mol^?1.cm^?1 for Nd and 367 1.mol^?1.cm^?1 for Er. The calibration graphs were linear up to 11.8 μg/ml of Nd and 12.3 μg/ml of Er, respectively. The relative standard deviations evaluated from eleven independent determinations of 7.2 μg/ml (for Nd) and 8.3 μg/ml (for Er) are 1.3% and 1.4%, respectively. The detection limits (signal to noise ratio = 2) are 0.2 μg/ml for Nd and 0.3 μg/ml for Er. The method has been developed for determining those two elements in mixture of lanthanides by means of the third-derivative spectra and the analytical results obtained are satisfactory.     

Medicinal Flowers. Part 29. Acylated Oleanane‐Type Triterpene Bisdesmosides: Perennisaponins G,H, I,J, K,L, and M with Pancreatic Lipase Inhibitory Activity from the Flowers of Bellis perennis

The MeOH extract from the flowers of Bellis perennis was found to show pancreatic‐lipase inhibitory activity (IC₅₀ 455 μg/ml). From the extract, seven new triterpene saponins named perennisaponins G ( 1 ; IC₅₀ 163 μM ), H ( 2 ; 137 μM ), I ( 3 ; 147 μM ), J ( 4 ; 148 μM ), K ( 5 ; 223 μM ), L ( 6 ; 81.4 μM ), and M ( 7 ; 195 μM ) were isolated as pancreatic lipase inhibitors. The stereostructures of 1 – 7 were elucidated on the basis of chemical and spectroscopic evidence.     

Concentricolide,an Anti‐HIV Agent from the Ascomycete Daldinia concentrica

A novel benzofuran lactone, named concentricolide (= rel‐(6R)‐6‐ethylbenzo[2,1‐b:3,4‐c′]difuran‐8(6H)‐one; 1 ), was isolated along with four known compounds (friedelin, cytochalasin L‐696,474, armillaramide, and russulamide) from the fruiting bodies of the xylariaceous ascomycete Daldinia concentrica. The structure of 1 was established by spectroscopic methods and X‐ray crystallographic analysis. Its anti‐HIV‐1 activity was tested. Results showed that 1 inhibited HIV‐1 induced cytopathic effects. The EC₅₀ value was 0.31 μg/ml. The therapeutic index (TI) was 247. Concentricolide exhibited the blockage (EC₅₀ 0.83 μg/ml) on syncytium formation between HIV‐1 infected cells and normal cells.     

Efficient synthesis of cytotoxic quinones: 2-Acetyl-4H,9H-naphtho[2,3-b]furan-4,9-dione (6) and (±)-2-(1-hydroxyethyl)-4H,9H-naphtho[2,3-b]furan-4,9-dione (7)

From the ethanol extract of the stem bark of Tabebuia cassinoides (Lam.) DC (Bignoniaceae), Kingston and Rao [1] isolated two new furonaphthoquinones 6 and 7 that showed activity in KB cell culture assay (ED₅₀ 1.0 and 2.0 μg/ml, respectively). These values may be significant since lapachol, which has an ED₅₀ value of 4.4 μg/ml in the same assay, showed sufficient in vivo activity to reach clinical trial at the National Cancer Institute of the United States. The syntheses of these compounds ( 6 and 7 ) were realized in 36% overall yield starting from furan and phthalic anhydride.