Neuroprotective effect of edible brown alga Eisenia bicyclis on amyloid beta peptide-induced toxicity in PC12 cells

Amyloid beta peptide (A??) oligomers increase intracellular reactive oxygen species (ROS) and calcium cation (Ca²⁺) concentrations, which causes neuronal cell death in Alzheimer??s disease (AD). Thus, the use of neuroprotective agents with antioxidative activity might be effective in the treatment of AD. In the present study, the neuroprotective effects of the methanol extract from edible brown alga Eisenia bicyclis (Laminariaceae) and its solvent soluble fractions together with the isolated phlorotannins on A??-induced toxicity were assessed by cell viability, intracellular ROS, and Ca²⁺ levels in PC12 cells. The addition of the methanol extract as well as its ethyl acetate and n-butanol fractions of E. bicyclis markedly reversed the A??-induced toxicity. Among six phlorotannins, including phloroglucinol (1), dioxinodehydroeckol (2), eckol (3), phlorofucofuroeckol A (4), dieckol (5), and 7-phloroeckol (6), isolated from the most active ethyl acetate fraction, 3?C6 significantly decreased A??-induced cell death. Furthermore, these compounds also inhibited intracellular ROS generation and Ca²⁺ generation, indicating the neuroprotective effects may be mediated through reduced intracellular ROS and Ca²⁺ generation. Thus, the results of the present study imply that E. bicyclis and its active components attenuated the oxidative stress and reduced neuronal cell death, suggesting that it may be used as a dietary neuroprotective agent in AD.     

Vascular barrier protective effects of phlorotannins on HMGB1-mediated proinflammatory responses in vitro and in vivo

The phlorotannins (phloroglucinol, eckol, and dieckol) are active compounds found in Eisenia bicyclis, and have been widely investigated for their antioxidant, anti-tumor, and anti-cancer activities. In this study, we investigated the protective effects of these phlorotannins against pro-inflammatory responses in human umbilical vein endothelial cells (HUVECs) and in mice treated by high mobility group box 1 protein (HMGB1), and the signaling pathways involved. The protective activities of the phlorotannins were determined by measuring permeability, leukocyte adhesion and migration, and the activations of pro-inflammatory proteins in HMGB1-activated HUVECs. We found that the phlorotannins inhibited; lipopolysaccharide (LPS)-induced HMGB1 release, HMGB1-mediated barrier disruption, the expressions of cell adhesion molecules (CAMs), and the adhesion/transendothelial migration of leukocytes to human endothelial cells. The phlorotannins also suppressed acetic acid induced-hyperpermeability and carboxymethylcellulose-induced leukocytes migration in vivo. Further studies revealed that the hydroxyl groups on dieckol positively regulated these vascular barrier protective effects. Collectively, these results suggest that phloroglucinol, eckol, and dieckol protect vascular barrier integrity by inhibiting hyperpermeability, the expressions of CAMs, and the adhesion and migration of leukocytes, which confirms their potential usefulnesses for the treatment of vascular inflammatory diseases.     

<Emphasis Type="Italic">Apium graveolens</Emphasis> extract influences mood and cognition in healthy mice

Apium graveolens is a food flavoring which possesses various health promoting effects. This study investigates the effect of a sub-acute administration of A. graveolens on cognition and anti-depression behaviors via antioxidant and related neurotransmitter systems in mice brains. Cognition and depression was assessed by various models of behavior. The antioxidant system of glutathione peroxidase (GPx), % inhibition of superoxide anion (O₂ ^?), and lipid peroxidation were studied. In addition, neurochemical parameters including acetylcholinesterase (AChE) and monoamine oxidase-type A (MAO-A) were also evaluated. Nine groups of male mice were fed for 30 days with different substances—a control, vehicle, A. graveolens extract (65–500 mg/kg), and reference drugs (donepezil and fluoxetine). The results indicated that the effect of the intake of A. graveolens extract (125–500 mg/kg) was similar to the reference drugs, as it improved both spatial and non-spatial memories. Moreover, there was a decrease in immobility time in both the forced swimming and tail suspension tests. In addition, the A. graveolens extract reduced lipid peroxidation of the brain and increased GPx activity and the % inhibition of O₂ ^?, whereas the activities of AChE and MAO-A were decreased. Thus, our data have shown that the consumption of A. graveolens extract improved cognitive function and anti-depression activities as well as modulating the endogenous antioxidant and neurotransmitter systems in the brain, resulting in increased neuronal density. This result indicated an important role for A. graveolens extract in preventing age-associated decline in cognitive function associated with depression.     

Synthesis,characterization and antimicrobial activity of 4-((1-benzyl/phenyl-1<Emphasis Type="Italic">H</Emphasis>-1,2,3-triazol-4-yl)methoxy)benzaldehyde analogues

A diverse series of 4-((1-benzyl/phenyl-1H-1,2,3-triazol-4-yl)methoxy)benzaldehyde analogues has been synthesized in good yield by the click reaction between 4-O-propargylated benzaldehyde and various organic bromides/azides. All the synthesized compounds were tested in vitro for their antimicrobial activity against Gram-positive bacteria (Staphylococcus epidermidis and Bacillus subtilis), Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and fungi (Candida albicans and Aspergillus niger). Most of the compounds exhibited good-to-excellent antimicrobial activity. Compound 7b was found to be more potent than ciprofloxacin against B. subtilis, whereas it showed activity comparable to ciprofloxacin against E. coli. Compounds 4h and 4i showed activity comparable to fluconazole against A. niger. Further, the binding mode of compound 7b into the active site of E. coli topoisomerase II DNA gyrase B has also been investigated.     

Inhibition of <Emphasis Type="Italic">Klebsiella pneumoniae</Emphasis> growth by selected Australian plants: natural approaches for the prevention and management of ankylosing spondylitis

A wide variety of herbal remedies are used in traditional Australian medicine to treat inflammatory disorders, including autoimmune inflammatory diseases. One hundred and six extracts from 40 native Australian plant species traditionally used for the treatment of inflammation and/or to inhibit bacterial growth were investigated for their ability to inhibit the growth of a microbial trigger for ankylosing spondylitis (K. pneumoniae). Eighty-six of the extracts (81.1%) inhibited the growth of K. pneumoniae. The D. leichardtii, Eucalyptus spp., K. flavescens, Leptospermum spp., M. quinquenervia, Petalostigma spp., P. angustifolium, S. spinescens, S. australe, S. forte and Tasmannia spp. extracts were effective K. pneumoniae growth inhibitors, with MIC values generally <1000 µg/mL. The T. lanceolata peppercorn extracts were the most potent growth inhibitors, with MIC values as low as 16 µg/mL. These extracts were examined by non-biased GC–MS headspace analysis and comparison with a compound database. A notable feature was the high relative abundance of the sesquiterpenoids polygodial, guaiol and caryophyllene oxide, and the monoterpenoids linalool, cineole and α-terpineol in the T. lanceolata peppercorn methanolic and aqueous extracts. The extracts with the most potent K. pneumoniae inhibitory activity (including the T. lanceolata peppercorn extracts) were nontoxic in the Artemia nauplii bioassay. The lack of toxicity and the growth inhibitory activity of these extracts against K. pneumoniae indicate their potential for both preventing the onset of ankylosing spondylitis and minimising its symptoms once the disease is established.     

Synthesis,antimicrobial and nematicidal evaluation of a new class of triazolo[4,3-<Emphasis Type="Italic">c</Emphasis>]quinazolinylthiazolidinones

In an attempt to find a new class of antimicrobial and nematicidal agents, a series of 2-aryl/heteryl-3-(5-phenyl[1,2,4]triazolo[4,3-c]quinazolin-3-yl)-1,3-thiazolidin-4-ones 5a-k was prepared by one-pot three-component reaction, involving 5-phenyl[1,2,4]triazolo[4,3-c]quinazolin-3-amine 4, aryl/heteroaryl aldehydes and thioglycolic acid, and characterized by physicochemical as well as spectral means. All the newly synthesized compounds 5a–k were tested in vitro for their antimicrobial activity against three representative Gram-positive (Bacillus subtilis, Staphylococcus aureus, Micrococcus luteus), Gram-negative (Proteus vulgaris, Salmonella typhimurium, Escherichia coli) bacteria and four fungal strains (Candida albicans, Aspergillus fumigatus, Trichophyton rubrum, Trichophyton mentagrophytes). These compounds 5a–k, were also evaluated for their nematicidal activity against two nematodes (Ditylenchus myceliophagus, Caenorhabditis elegans). Except phenyl substituted, all the ten aryl/heteroaryl substituted compounds 5b–k showed significant antimicrobial and nematicidal properties against tested microorganisms. Particularly, compounds 5b, 5c, 5g, 5h, 5j and 5k containing electron-withdrawing substituents like chlorophenyl, nitrophenyl, furyl and 1,3-benzodioxole exhibited promising activity comparable to employed standards Ampicillin, Amphotericin B and Levamisole, and emerged as potent antimicrobial and nematicidal agents.     

Synthesis and evaluation of <Emphasis Type="Italic">p</Emphasis>-<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-dialkyl substituted chalcones as anti-cancer agents

Several new N,N-dialkyl substituted chalcones (chalconoids or benzylideneacetophenones) have been synthesized via the condensation of corresponding N,N-dialkylbenzaldehyde with various aryl methyl ketones. All the chalcones have been synthesized from readily available and cheap starting materials under environmentally benign conditions in very high yields without work up and column chromatographic purification. Synthesized compounds have been tested for their biological activity against pathogenic microorganisms such as Escherichia coli, Bacillus subtilis, and Mycobacterium smegmatis. Anti-cancer activity of these compounds has also been tested against multiple myeloma (RPMI-8226) and human mammary adenocarcinoma (MCF-7) cell lines. The most hydrophilic molecules 23 and 24 showed very good anti-cancer activity against MCF-7 cell lines at low micro-molar concentrations. All the compounds have also been evaluated for their activity against Beta-secretase 1 enzyme. One of the synthesized compounds showed Beta-secretase 1 enzyme inhibition activity at micro-molar concentration.     

Molecular cloning,sequence analysis,and tissue distribution of marmoset monoamine oxidases A and B

The common marmoset (Callithrix jacchus), a New World primate, is currently attracting much attention as a nonhuman primate model for pharmacological and pharmacokinetic studies in preclinical research. In this study, we newly isolated the cDNAs of marmoset monoamine oxidase A (MAO-A) and MAO-B from liver and brain, respectively. MAO-A and MAO-B cDNAs, respectively, contained open reading frames of 527 and 520 amino acids and were approximately 92% and 95% identical to their human orthologs. Marmoset MAOs were phylogenetically closer to primate MAOs, including human MAOs, than to pig, dog, or rodent MAOs. The genomic and gene structures of marmoset MAOs were similar to those of humans. Among the five marmoset tissue types analyzed, the expression levels of MAO-A mRNA were relatively abundant in lung, liver, kidney, and small intestine, whereas the expression levels of MAO-B mRNA were relatively abundant in brain, liver, kidney, and small intestine; these tissue distributions are similar to those of human MAOs. These results suggest that MAO-A and MAO-B are similar at a molecular level in marmosets and humans.     

The BioGIT System: a Valuable <Emphasis Type="Italic">In Vitro</Emphasis> Tool to Assess the Impact of Dose and Formulation on Early Exposure to Low Solubility Drugs After Oral Administration

The purpose of this study was to evaluate the usefulness of the in vitro biorelevant gastrointestinal transfer (BioGIT) system in assessing the impact of dose and formulation on early exposure by comparing in vitro data with previously collected human plasma data of low solubility active pharmaceutical ingredients. Eight model active pharmaceutical ingredients were tested; Lu 35-138C (salt of weak base in a HP-beta-CD solution, three doses), fenofibrate (solid dispersion, tablet, two doses), AZD2207 EQ (salt of weak base, capsule, three doses), posaconazole (Noxafil® suspension, two doses), SB705498 (weak base, tablets vs. capsules), cyclosporine A (Sandimmun® vs. Sandimmun® Neoral), nifedipine (Adalat® capsule vs. Macorel® tablet), and itraconazole (Sporanox® capsule vs. Sporanox® solution). AUC_0–0.75h values were calculated from the apparent concentration versus time data in the duodenal compartment of the BioGIT system. Differences in AUC_0–0.75h values were evaluated versus differences in AUC_0–1h and in AUC_0–2h values calculated from previously collected plasma data in healthy adults. Ratios of mean AUC_0–0.75h, mean AUC_0–1h, and mean AUC_0–2h values were estimated using the lowest dose or the formulation with the lower AUC_0–0.75h value as denominator. The BioGIT system qualitatively identified the impact of dose and of formulation on early exposure in all cases. Log-transformed mean BioGIT AUC_0–0.75h ratios correlated significantly with log-transformed mean plasma AUC_0–1h ratios. Based on this correlation, BioGIT AUC_0–0.75h ratios between 0.3 and 10 directly reflect corresponding plasma AUC_0–1h ratios. BioGIT system is a valuable tool for the assessment of the impact of dose and formulation on early exposure to low solubility drugs.     

Chemical composition and bioactivities of the essential oil from different organs of <Emphasis Type="Italic">Ferula communis</Emphasis> L. growing in Tunisia

The essential oils obtained by the hydrodistillation from the fresh flowers, leaves, stems, and roots of Ferula communis L., growing in Tunisia were analyzed by GC and GC/MS. Thirty-two components were identified in the oil of flowers with camphor (18.3 %), α-pinene (15.3 %), and β-eudesmol (9.3 %) as the main constituents. Twenty-nine compounds were identified in the oil of stems with β-eudesmol (28.1 %), δ-eudesmol (11.1 %), and α-eudesmol (9.6 %) as the main compounds. Twenty compounds were characterized in the oil of roots with dillapiole (7.9 %), guaiol (7.3 %), and spathulenol (6.8 %). In the oil of leaves, α-eudesmol (25.2 %), β-eudesmol (20.7 %), δ-eudesmol (10.1 %), and caryophyllene oxide (7.2 %) were found as the main constituents. This study was undertaken to evaluate the antioxidant activity using DPPH (2,2′-diphenyl-1-picrylhydrazyl), ABTS (2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid), reducing power, and catalase activity. We tested also the antibacterial, cytotoxic, and cholinesterase inhibition properties of the essential oil of different organs of F. communis. The essential oil of the stems showed the highest antioxidant activity (IC₅₀ = 0.03 ± 0.001 mg mL^?1), in DPPH assay and the important result of catalase (303.03 µmol H₂O₂ degraded/min/protein) of F. communis. The antibacterial activity of the oil was determined by micro-well dilution assay. The best results (MIC = 0.156 ± 0.02 mg mL^?1) were exhibited by the essential oil of the leaves of F. Communis against Pseudomonas aeruginosa. Besides, the strongest cytotoxic activity against Hela cells was shown with essential oils’ leaves with an inhibition percentage of 79.05 % at the concentration of 500 µg mL^?1. However, the best inhibition percentage of A 549 cells was detected for essential oils’ leaves with an inhibition percentage of 54.56 % at 250 µg mL^?1. Our finding showed that the essential oil of the flowers was the most active, with 64.623 % of inhibition against butyrylcholinesterase at 10 mg mL^?1 from the incubation time of 30 min.     

Pharmacodynamic Model of Hepcidin Regulation of Iron Homeostasis in Cynomolgus Monkeys

Hepcidin (H₂₅) is a hormone peptide synthesized by the liver that binds to ferroportin and blocks iron export. In this study, H₂₅ was inhibited by administration of single and multiple doses of an anti-H₂₅ monoclonal antibody Ab 12B9m in cynomolgus monkeys. The objective of this analysis was to develop a pharmacodynamic model describing the role of H₂₅ in regulating iron homeostasis and the impact of hepcidin inhibition by Ab 12B9m. Total serum H₂₅ and Ab 12B9m were determined in each animal. Corresponding measurements of serum iron and hemoglobin (Hb) were obtained. The PD model consisted of iron pools in serum (Fe_S), reticuloendothelial macrophages (Fe_M), hemoglobin (Fe_Hb), and liver (Fe_L). The iron was assumed to be transported between the Fe_S, Fe_Hb, and Fe_M unidirectionally at rates k _S, k _Hb, and k _M. H₂₅ serum concentrations were described by the previously developed PK model with the parameters fixed at their estimates. The serum iron and Hb data were fitted simultaneously. The corresponding estimates of the rate constants were k _S/Fe₀?=?0.113 h^?1, k _M?=?0.00191 h^?1, and k _Hb?=?0.00817 h^?1. The model-based IC₅₀ value for the H₂₅ inhibitory effect on ferroportin activity was 0.398 nM. The PD model predicted a negligible effect of Ab 12B9m on Hb levels for the tested doses. The presented PD model adequately described the serum iron time courses following single and multiple doses of Ab 12B9m. Ab 12B9m-induced inhibition of H₂₅ resulted in a temporal increase in serum and liver iron and a decrease in the iron stored in reticuloendothelial macrophages.     

Measuring cytochrome P450 activity in aquatic invertebrates: a critical evaluation of in vitro and in vivo methods

The first step in xenobiotic detoxification in aquatic invertebrates is mainly governed by the cytochrome P450 mixed function oxidase system. The ability to measure cytochrome P450 activity provides an important tool to understand macroinvertebrates’ responses to chemical stressors. However, measurements of P450 activity in small aquatic invertebrates have had variable success and a well characterized assay is not yet available. The general lack of success has been scarcely investigated and it is therefore the focus of the present work. In particular, the suitability of the substrate selected for the assay, the sensitivity of the assay and the possible inhibition/attenuation of enzymatic activity caused by endogenous substances were investigated. 7-ethoxycoumarin-O-dealkylation activity of Daphnia magna, Chironomus riparius larvae and Hyalella azteca was assessed in vivo and in vitro and possible inhibition of enzymatic activity by macroinvertebrates homogenate was investigated. Activities of D. magna and C. riparius larvae measured in vivo were 1.37 ± 0.08 and 2.2 ± 0.2 pmol h^?1 organism^?1, respectively, while activity of H. azteca could not be detected. In vitro activity could be measured in C. riparius larvae only (500–1000 pmol h^?1 mg microsomal protein^?1). The optimization of the in vitro assay has been especially long and resource consuming and particularly for D. magna, substances that inhibited cytochrome P450 activity seemed to be released during tissue homogenization preventing activity measurements in vitro. We therefore recommend testing the P450 inhibition potential of homogenate preparations prior to any investigation of P450 activity in vitro in macroinvertebrates.     

Synthesis of novel triazolyl pyranochromen-2(1<Emphasis Type="Italic">H</Emphasis>)-ones and their antibacterial activity evaluation

A series of thirty-three novel triazolyl pyranochromen-2(1H)-one derivatives have been synthesized via Cu (I) catalysed Huisgen 1,3-dipolar cycloaddition reaction. All of the synthesized compounds have been fully characterized from their spectral data and evaluated for antibacterial activity against both gram-positive and gram-negative bacteria. The activity results revealed that amongst all the compounds screened, six compounds, i.e. 2-[4-(((7-ethyl-2,2,6-trimethyl-8-oxo-2,3,4,8-tetrahydropyrano[3,2-g]chromen-10-yl)oxy)methyl)-1H-1,2,3-triazol-1-yl]acetic acid (41), 10-[(1-(1,3-dihydroxypropan-2-yl)-1H-1,2,3-triazol-4-yl)methoxy]-3-ethyl-4,8,8-trimethyl-7,8-dihydropyrano[3,2-g]chromen-2(6H)-one (44), 3-ethyl-4,8,8-trimethyl-10-[(1-((2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran-2-yl)-1H-1,2,3-triazol-4-yl)methoxy]-7,8-dihydropyrano[3,2-g]chromen-2(6H)-one (46), 2-[4-(((7-hexyl-2,2,6-trimethyl-8-oxo-2,3,4,8-tetrahydropyrano[3,2-g]chromen-10-yl)oxy)methyl)-1H-1,2,3-triazol-1-yl]acetic acid (52), 10-[(1-(1,3-dihydroxypropan-2-yl)-1H-1,2,3-triazol-4-yl)methoxy]-3-hexyl-4,8,8-trimethyl-7,8-dihydropyrano[3,2-g]chromen-2(6H)-one (55) and 3-hexyl-4,8,8-trimethyl-10-[(1-((2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran-2-yl)-1H-1,2,3-triazol-4-yl)methoxy]-7,8-dihydropyrano[3,2-g]chromen-2(6H)-one (57), exhibited moderate activity against all the strains studied with zone of inhibition between 10 and 16 mm and MIC values in the range of 75–170 µg/mL as compared to the standard used. The information obtained from structure–activity relationship can be used to design and develop the next generation of compounds with higher antibacterial efficacy.     

Synthesis and biological evaluation of quinolines,thiazolo[3,2-<Emphasis Type="Italic">a</Emphasis>]pyrimidines,thiadiazolo[3,2-<Emphasis Type="Italic">a</Emphasis>]pyrimidines and triazolo[3,4-<Emphasis Type="Italic">b</Emphasis>][1,3,4]thiadiazepines as antimicrobial agents

Series of quinolines, thiazolo[3,2-a]pyrimidines, thiadiazolo[3,2-a]pyrimidines and triazolo[3,4-b][1,3,4]thiadiazepines were synthesized by the reaction of amino compound, aromatic aldehyde and malononitrile/ethyl cyanoacetate, using 2-[5-(4-methoxyphenyl)-4H-1,2,4-triazol-3-ylthio]acetic acid as an organocatalyst in water–ethanol mixture. Synthesized compounds were evaluated for in vitro antibacterial and antifungal activities against three fungal and five bacterial strains. Some of them exhibited good activity in comparison with the standard fluconazole and streptomycin such as compound 16h has shown best antifungal activity with MIC value of 60 µg/mL against A. niger and 12g exhibited best antibacterial activity with MIC value of 50 µg/mL against E. coli.     

Protective effect of phlorotannins from Eisenia bicyclis against lipopolysaccharide-stimulated inflammation in HepG2 cells

In this study, four bioactive phloroglucinol derivates including phloroglucinol (1), eckol (2), dioxinodehydroeckol (3), and dieckol (4) were isolated from Eisenia bicyclis and characterized by nuclear magnetic resonance (NMR) spectroscopic methods. Moreover, the anti-inflammatory activity of these compounds was investigated on human hepatoma cell line HepG2 cells stimulated by lipopolysaccharide (LPS). It was demonstrated that LPS can induce the production of pro-inflammatory cytokines such as interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) as well as the expression of inflammatory mediators as cyclooxygenase-2 (COX-2), and inducible nitric oxide synthases (iNOS) from HepG2 cells. Among isolated compounds, compound (1) exhibited significant inhibition on LPS-stimulated inflammatory responses in HepG2 cells without any cytotoxicity. Herein, compound (1) suppresses the production of pro-inflammatory cytokines such as IL-1β, IL-6, and TNF-α and the expression of COX-2 and iNOS. Thus, these results indicated that phlorotannins isolated from E. bicyclis, especially compound (1), can be used as a beneficial source for preventing and treating inflammation response.     

Simulation-Based Evaluation of PK/PD Indices for Meropenem Across Patient Groups and Experimental Designs

Purpose

Antibiotic dose predictions based on PK/PD indices rely on that the index type and magnitude is insensitive to the pharmacokinetics (PK), the dosing regimen, and bacterial susceptibility. In this work we perform simulations to challenge these assumptions for meropenem and Pseudomonas aeruginosa.

Methods

A published murine dose fractionation study was replicated in silico. The sensitivity of the PK/PD index towards experimental design, drug susceptibility, uncertainty in MIC and different PK profiles was evaluated.

Results

The previous murine study data were well replicated with fT?>?MIC selected as the best predictor. However, for increased dosing frequencies fAUC/MIC was found to be more predictive and the magnitude of the index was sensitive to drug susceptibility. With human PK fT?>?MIC and fAUC/MIC had similar predictive capacities with preference for fT?>?MIC when short t_1/2 and fAUC/MIC when long t_1/2.

Conclusions

A longitudinal PKPD model based on in vitro data successfully predicted a previous in vivo study of meropenem. The type and magnitude of the PK/PD index were sensitive to the experimental design, the MIC and the PK. Therefore, it may be preferable to perform simulations for dose selection based on an integrated PK-PKPD model rather than using a fixed PK/PD index target.

     

Influence of Copolymer Composition on <Emphasis Type="Italic">In Vitro</Emphasis> and <Emphasis Type="Italic">In Vivo</Emphasis> Performance of Celecoxib-PVP/VA Amorphous Solid Dispersions

Previous studies suggested that an amorphous solid dispersion with a copolymer consisting of both hydrophobic and hydrophilic monomers could improve the dissolution profile of a poorly water-soluble drug compared to the crystalline form. Therefore, this study investigated the influence of the copolymer composition of polyvinylpyrrolidone/vinyl acetate (PVP/VA) on the non-sink in vitro dissolution behavior and in vivo performance of celecoxib (CCX) amorphous solid dispersions. The study showed that the hydrophilic monomer vinylpyrrolidone (VP) was responsible for the generation of CCX supersaturation whereas the hydrophobic monomer vinyl acetate (VA) was responsible for the stabilization of the supersaturated solution. For CCX, there was an optimal copolymer composition around 50–60% VP content where further replacement of VP monomers with VA monomers did not have any biopharmaceutical advantages. A linear relationship was found between the in vitro AUC_0-4h and in vivo AUC_0-24h for the CCX:PVP/VA systems, indicating that the non-sink in vitro dissolution method applied in this study was useful in predicting the in vivo performance. These results indicated that when formulating a poorly water-soluble drug as an amorphous solid dispersion using a copolymer, the copolymer composition has a significant influence on the dissolution profile and in vivo performance. Thus, the dissolution profile of a drug can theoretically be tailored by changing the monomer ratio of a copolymer with respect to the required in vivo plasma-concentration profile. As this ratio is likely to be drug dependent, determining the optimal ratio between the hydrophilic (dissolution enhancing) and hydrophobic (crystallization inhibiting) monomers for a given drug is imperative.     

C<Subscript>21</Subscript> steroid derivatives from the Dai herbal medicine Dai-Bai-Jie,the dried roots of <Emphasis Type="Italic">Marsdenia tenacissima</Emphasis>, and their screening for anti-HIV activity

Twenty-three new C₂₁ steroidal glycosides, marstenacissides C1–C10 (1–10), D1–D7 (11–17) and E1–E6 (18–23), and four new C₂₁ steroids, 11α,12β-O-ditigloyl-tenacigenin C (24), 11α-O-benzoyl-12β-O-tigloyl-tenacigenin C (25), 11α-O-tigloyl-12β-O-benzoyl-tenacigenin C (26) and 11α-O-tigloyl-12β-O-benzoyl-marsdenin (27), were isolated from the Dai herbal medicine Dai-Bai-Jie, derived from the roots of Marsdenia tenacissima. The chemical structures of all compounds were established by spectroscopic techniques, including high-resolution mass spectrometry and NMR spectroscopy, as well as by comparison with reported spectral data. The anti-HIV activities of these compounds were screened, and the compounds obtained displayed inhibitory effects against HIV-1 with inhibition rates of 36.4–81.3% at 30 μM.     

New ursane triterpenoids from <Emphasis Type="Italic">Ficus pandurata</Emphasis> and their binding affinity for human cannabinoid and opioid receptors

Phytochemical investigation of Ficus pandurata Hance (Moraceae) fruits has led to the isolation of two new triterpenoids, ficupanduratin A [1β-hydroxy-3β-acetoxy-11α-methoxy-urs-12-ene] (11) and ficupanduratin B [21α-hydroxy-3β-acetoxy-11α-methoxy-urs-12-ene] (17), along with 20 known compounds: α-amyrin acetate (1), α-amyrin (2), 3β-acetoxy-20-taraxasten-22-one (3), 3β-acetoxy-11α-methoxy-olean-12-ene (4), 3β-acetoxy-11α-methoxy-12-ursene (5), 11-oxo-α-amyrin acetate (6), 11-oxo-β-amyrin acetate (7), palmitic acid (8), stigmast-4,22-diene-3,6-dione (9), stigmast-4-ene-3,6-dione (10), stigmasterol (12), β-sitosterol (13), stigmast-22-ene-3,6-dione (14), stigmastane-3,6-dione (15), 3β,21β-dihydroxy-11α-methoxy-olean-12-ene (16), 3β-hydroxy-11α-methoxyurs-12-ene (18), 6-hydroxystigmast-4,22-diene-3-one (19), 6-hydroxystigmast-4-ene-3-one (20), 11α,21α-dihydroxy-3β-acetoxy-urs-12-ene (21), and β-sitosterol-3-O-β-d-glucopyranoside (22). Compound 21 is reported for the first time from a natural source. The structures of the 20 compounds were elucidated on the basis of IR, 1D (¹H and ¹³C), 2D (¹H–¹H COSY, HSQC, HMBC and NOESY) NMR and MS spectroscopic data, in addition to comparison with literature data. The isolated compounds were evaluated for their anti-microbial, anti-malarial, anti-leishmanial, and cytotoxic activities. In addition, their radioligand displacement affinity on opioid and cannabinoid receptors was assessed. Compounds 4, 11, and 15 exhibited good affinity towards the CB2 receptor, with displacement values of 69.7, 62.5 and 86.5 %, respectively. Furthermore, the binding mode of the active compounds in the active site of the CB2 cannabinoid receptors was investigated through molecular modelling.     

<Emphasis Type="Italic">Spatholobus suberectus</Emphasis> Dunn. constituents inhibit sortase A and <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> cell clumping to fibrinogen

Sortases are a family of Gram-positive transpeptidases responsible for anchoring surface protein virulence factors to the peptidoglycan cell wall layer. In Staphylococcus aureus (S. aureus), deletion of sortase isoform results in a significant reduction in virulence and infection potential. Twenty flavonoids were isolated from the stem of the folk medicinal plant Spatholobus suberectus Dunn. These compounds were tested against S. aureus-derived sortase A (SrtA), a key transpeptidase for bacterial virulence. Among these active flavonoids, 7-hydroxy-6-methoxy-flavanone (3) and formononetin (10) were identified as compounds with promising SrtA inhibitory activity. These compounds also exhibited inhibitory activity against S. aureus cell clumping to fibrinogen. The suppression of cell-clumping activity indicates the potential of these compounds in the treatment of S. aureus infections via the inhibition of SrtA.