In vitro inhibitory effects of plumbagin,the promising antimalarial candidate,on human cytochrome P450 enzymes

Objective:To investigate the propensity of plumbagin to inhibit the three isoforms of human cytochrome P450(CYP),ie.,CYP1A2,CYP2C19,and CYP3A4 using human liver microsomes in ritro.Methods:Inhibitory effects of plumbagin on the three human CYP isoformswere investigated using pooled human liver microsomes.Phenacetin O-deethylation,omeprazole hydroxylation and nifedipine oxidation were used as selective substrates for CYP1A2,CYP2C19 and CYP3A4 activities,respectively.Concentrations of paracetamol,5-hydroxyomeprazole,and oxidized nifedipine were determined in microsomal incubation mixture using high performance liquid chromatography.Results:Plumbagin showed significantinhibitory effects on all CYP isoforms.but with the most potent activity on CYP2C19-mediated omeprazole hydroxylation.The IC50(concentration that inhibits enzyme activity by 50%) values of plumbagin and nootkatone(selective inhibitor) for CYP2C19 were(0.78±0.01) and(27.31±0.66) μM,respectively.The inhibitory activities on CYP1 A2-mediated phenacetin O-deethylation and CYP3A4-mediated nifedipine oxidation were moderate.The IC_(50) values of plumbagin and-naphthoflavone(selective inhibitor) for CYP1A2 were(1.39±0.01) and(0.02±.0.36) μM,respectively.The corresponding IC_(50) values of plumbagin and ketoconazole(selective inhibitor) for CYP3A4 were(2.37+0.10) and(0.18±0.06) μM,respectively.Conclusions:Clinical relevance of the interference of human drug metabolizing enzymes should be aware of for further development scheme of plumbagin as antimalarial drug when used in combination with other antimalarial drugs which are metabolized by these CYP isoforms.

The role of heme-oxygenase-1 in pathogenesis of cerebral malaria in the co-culture model of human brain microvascular endothelial cell and ITG Plasmodium falciparum-infected red blood cells

Objective: To investigate the role of human host heme-oxygenase-1(HO-1) in pathogenesis of cerebral malaria in the in vitro model,Methods: The effect of human host HO-1 [human brain microvascular endothelial cell(HBMEC)] on hemoglobin degradation in the co-culture model of HBMEC and ITG Plasmodium falciparum-infected red cells(i RBC) through measurement of the enzymatic products iron and bilirubin,Results: Following exposure to the HO-1 inducer Co PPIX at all concentrations,the HBMEC cells apoptosis occurred,which could be prominently observed at 15 μM of 3 h exposure,In contrast,there was no significant change in the morphology in the non-exposed i RBC at all concentrations and exposure time,This observation was in agreement with the levels of the enzymatic degradation products iron and bilirubin,of which the highest levels(106.03 and 1 753.54% of baseline level,respectively) were observed at 15 μM vs,20 μM at 3 h vs,24 h exposure,For the effect of the HO-1 inhibitor Zn PPIX,HBMEC cell morphology was mostly unchanged,but significant inhibitory effect on cell apoptosis was seen at 10 μM for the exposure period of 3 h(37.17% of baseline level),The degree of the inhibitory effect as reflected by the level of iron produced was not clearly observed(highest effect at 10 μM and 3 h exposure),Conclusions: Results provide at least in part,insight into the contribution of HO-1 on CM pathogenesis and need to be confirmed in animal model.

Possible role of PGD_2 in malaria infections

Objective:To preliminarily investigate the possible role of prostaglandin D_2(PGD_2) in malaria infections.Methods:Blood and urinary samples(n=120 each) were collected from Thai patients with Plasmodium falciparum(P.falciparum) with moderate(n=26) and high(n=4) parasitemia,patients with Plasmodium vivax(P.vivax)(n=30),patients with fever associated with other infections(n=30),and healthy subjects(n=30).PGD_2 concentrations in plasma and urinary samples of healthy subjects,patients with fever associated with other infections and patients with malaria were determined using Prostaglandin D2-MOX express EIA kit(Cayman Chemical,USA).Results:The possible association between PGD_2 and malaria infections is clearly demonstrated with PGD_2 concentration in urine.The urinary PGD_2 concentrations were relatively high(about 5-fold) in patients with P.falciparum with moderate parasitemia and P.vivax infections compared with other groups.Furthermore,the concentration in patients with P.falciparum with moderate parasitemia and P.vivax infection were significantly higher than that in healthy subjects and patients with fever associated with other infections.Conclusions:Urinary PGD_2 concentrations may offer a more dependable and useful tool for predicting malaria severity.Confirmation is this preliminary finding is required with a larger sample size.

Glycoproteomics analysis of plasma proteins associated with Opisthorchis viverrini infection-induced cholangiocarcinoma in hamster model

Objective: To apply lectin affinity chromatography and glycoproteomics-based LC-MS/MS to preliminarily investigate the possible potential plasma biomarkers of Opisthorchis viverrini(OV)-associated CCA in OV/dimethylnitrosamine(DMN)-induced CCA hamster model. Methods: Nine Syrian hamsters were divided into 3 groups as follows(n=3 each): normal(healthy control group); OV group; and OV/DMN group(CCA group). Pooled plasma samples collected from animals in each group at the 6th month post-infection with OV metacercarae were subjected to glycoproteomics analysis. Glycoproteins in the pooled sample from each group were initially isolated by concanavilin A(Con A)-based affinity chromatography. The expression of glycoproteins isolated by both enrichment methods were determined using LCMS/MS. Results: Among the 24 Con A-binding glycoproteins isolated, two proteins, N-myc downstream regulated gene 1(NDRG1) and fetuin-B(FETUB) were found up-regulated only in the samples from the OV and control groups, but not in the OV/DMN(CCA) groups. On the other hand, one protein, i.e., NSFL1 cofactor p47 isoform x3(NSFL1C) was found only in the samples from OV/DMN(CCA) and control groups, but not in the OV group. The remaining 21 proteins were upregulated in the samples from all groups. Conclusions: NDRG1, FETUB and NSFL1 C glycoproteins isolated by Con A-based affinity chromatography could be potential biomarkers for CCA. Plasma samples with negative for NDRG1 and FETUB proteins but positive for NSFL1 C are likely to be OV-associated CCA. Nevertheless, this conclusion remains to be confirmed whether this battery test can discriminate OV-associated CCA from other risk factors.

Atractylodin-loaded PLGA nanoparticles：formulation and characterization

OBJECTIVE To formulate atractylodin-loaded poly(lactic-co-glycolic acid)(PLGA)nanoparticles and characterize the prepared nanoparticle formulation.METHODS The nanoparticle formulation was developed using solvent displacement method.The encapsulation and loading efficiency were characterized and particle size,and zeta potential were determined by dynamic light scattering technique.Drug release was assessed in vitro.RESULTS The size(mean±SD of diameter) of the prepared atractylodin-loaded PLGA nanoparticles were(161.27 ± 1.87)nm with narrow size distribution(mean PDI:0.068±0.015) and zeta potential(28.83±0.35)mV.The encapsulation and loading efficiency were(48.31±0.83)% and(2.15±0.04)%,respectively.Drug release from atractylodin-loaded PLGA nanoparticles was observed up to(87.70±0.47)% in 72 h with biphasic manner.Moreover,the nanoparticles were found to be freely dispersible in water without aggregation.CONCLUSION Results suggest that PLGA nanoparticles may be used as an effective drug delivery system for atractylodin.The anti-cholangiocarcinoma activity of this nanoparticle formulation is required.

Identification of potential protein targets of atractylodin against cholangiocarcinoma

OBJECTIVE To identify potential cell signaling pathways and protein targets of the active compound isolated from Atracylodes lancea "atractylodin" in cholangiocarcinoma,using proteomics approach.METHODS The holangiocar-cinoma cell line was exposed with atractylodin for 3 and 6 h and the proteins from both intra-and extra-cellular components were extracted.The extract proteins were separated by SDS-PAGE and digested with trypsin.The LC-MS/MS was applied to identify proteins.Signaling pathways and protein expression were analyzed by MASCOT and STITCH software.RESULTS A total of 4,323 and 4,318 proteins were identified from intra-and extracellular components,respectively.Six intracellular proteins were linked with the signaling pathways(apoptosis,cell cycle control,and PI3K-AKT).Four extracellular proteins were linked with the signaling pathways(NF-κB and PI3K-AKT).CONCLUSION All these proteins will further study to confirm the link to the anticholangiocarcinoma ac.tivity of actractylodin.

Development of oral pharmaceutical formulation of standardized crude ethanolic extract of Atractylodes lancea(Thunb) DC.

Cholangiocarcinoma(CCA), the adenocarcinoma of the biliary duct, is commonly reported in Asia with the highest incidence in northeastern Thailand. Chemotherapy of this type of cancer is limited due to the lack of effective chemotherapeutic drugs. A series of previous studies support further research and development of Atractylodes lancea(Thunb) DC.(AL) as a potential candidate for the treatment of CCA as a crude ethanolic extract. In the present study, we aimed to develop an oral pharmaceutical formulation(capsule) of the standardized AL crude ethanolic extract for further clinical development in patients with CCA. Major steps included macroscopic and microscopic authentication of the AL rhizomes, preparation of standardized AL extract, preparation of oral pharmaceutical formulation(capsule) of the standardized AL extract, quantitative and qualitative analysis of the marker compound(atractylodin) in the formulated AL extract, evaluation of contaminations of heavy metals, pesticides residues, and microorganisms in the ground AL rhizomes and the formulated(capsule) powder of AL, physicochemical and pharmaceutical properties of the formulated AL extract/capsule, and cytotoxicity evaluation of the formulated AL extract. Results of all evaluations confirmed satisfactory pharmaceutical properties of oral(capsule) formulation of the standardized AL extract.