Cytotoxic Steroidal Glycosides from the Whole Plant of Calamus acanthophyllus

A new steroidal glycoside, callaphylloside (1), together with seven known glycosides (2-8), was isolated from the whole plant of Calamus acanthophyllus. The structure of the new compound was elucidated by spectral data analyses and chemical transformations. Compounds 5 and 8 exhibited strong cytotoxic activity against four cancer cell lines (0.7 ≤ IC50 ≤ 3.4 µM). Evaluation of the structure-activity relationship among steroidal glycosides revealed that the structure of spirostanol with an α-L-rhamnopyranosyl linked to C-2 of the inner glucopyranosyl residue both play a critical role in the effects of these compounds on the cancer cell lines.

Ultrasound screening for cholangiocarcinoma could detect premalignant lesions and early-stage diseases with survival benefits: a population-based prospective study of 4,225 subjects in an endemic area

Background

Thailand has a high incidence of cholangiocarcinoma (CCA), particularly in the north and northeastern regions. Most CCA patients come at a late, unresectable stage and presently no optimal screening test for CCA has been established. We determined the prevalence of CCA in a remote northern village and explored if screening could lead to early detection and survival benefits.

Methods

A 5-year population-based study was started in October, 2011 for consented Thai individuals, aged 30–60 years. The screening program comprised blood testing, stool examination and serial ultrasonography every 6 months.

Results

During the first 3 years, 4,225 eligible individuals were enrolled. CCA was detected in 32 patients, with a mean age of 51.9 years (41–62 years), and 21/32 cases were at a curative resectable stage. The prevalence rate of CCA was 165.7 per 100,000 and one- and two-year incidence rate was 236.7/100,000 and 520.7/100,000, respectively. One- and 2-year overall survival rates of CCA patients were 90.9 and 61.5 %, respectively. Prognosis was better in resectable cases with 100 % 1-year and 77.8 % 2-year survival rates. Interestingly, premalignant pathological lesions (stage 0) were identified in 11 cases with 100 % 3-year survival rate. Serum biomarkers and alkaline phosphatase were not sufficient to detect early-stage disease. In 22 patients, stool samples were positive for Opistorchis viverrini, based on polymerase chain reaction.

Conclusion

Detection of premalignant lesions and early-stage resectable CCA by ultrasonography resulted in improved clinical outcome. Ultrasonography should be offered as a first screening tool for CCA in an endemic area until other useful biological markers become available.

Water-Assisted Nitrile Oxide Cycloadditions: Synthesis of Isoxazoles and Stereoselective Syntheses of Isoxazolines and 1,2,4-Oxadiazoles

Conventional methods generate nitrile oxides from oxime halides in organic solvents under basic conditions. However, the present work revealed that water-assisted generation of nitrile oxides proceeds under mild acidic conditions (pH 4-5). Cycloadditions of nitrile oxides with alkynes and alkenes easily occurred in water without using catalysts, thus yielding isoxazoles and isoxazolines, respectively, with excellent stereoselectivity toward five- and six-membered cyclic alkenes. A double stereoselective cycloaddition of two units of a nitrile oxide with cyclohexene was also achieved, thus yielding 1,2,4-oxadiazole derivatives having a unique hybrid isoxazoline-oxadiazole skeleton. Enantiomerically pure isoxazolines were prepared from monoterpenes with a ring strain. In one case, the isoxazoline with a butterfly-like structure was simply prepared, and it might be used as a ligand in asymmetric catalysis.

Cytotoxic sesquiterpenes from the endophytic fungus Pseudolagarobasidium acaciicola

Twenty previously unknown compounds and two known metabolites, merulin A and merulin D, were isolated from the endophytic fungus Pseudolagarobasidium acaciicola, which was isolated from a mangrove tree, Bruguiera gymnorrhiza. Structures of the 20 compounds were elucidated by analysis of spectroscopic data. The absolute configuration of seven of these compounds was addressed by a single crystal X-ray analysis using CuKα radiation and an estimate of the Flack parameter. Three compounds also possessed a tricyclic ring system. Terpene endoperoxides isolated exhibited cytotoxic activity, while those without an endoperoxide moiety did not show activity. The endoperoxide moiety of sesquiterpenes has significant impact on cytotoxic activity, and thus is an important functionality for cytotoxicity. One terpene endoperoxide displayed potent cytotoxic activity (IC50 0.28μM), and selectively exhibited activity against the HL-60 cell line.

Abstract LB-173: The Thailand initiative in genomics and expression research for liver cancer (TIGER-LC): Defining novel subtypes of hepatocellular carcinoma and cholangiocarcinoma

Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) represent two major histological cancer subtypes confined within the liver. They are clinically and biologically heterogeneous, and are highly resistant to treatment, which makes them the second most lethal cancer for men in the world. In Thailand, liver cancer represents the primary cause of cancer-related death and is a major health problem, especially in north-eastern area of Thailand where liver fluke (O. viverrini) is endemic and approximately 70% of liver cancers are CCA. While HBV and HCV are major etiological factors for HCC globally, liver fluke infection is a major etiological factor for CCA in Thailand. These unique risk factor patterns provide an opportunity to study cancer heterogeneity and its unique tumor biology. The Thailand Initiative in Genomics and Expression Research for Liver Cancer (TIGER-LC) consortium was established to identify genomic and expression factors that may modify HCC and CCA susceptibility and progression. In a Phase I study, we determined molecular subtypes of HCC and CCA. We performed genomic profiling of 398 surgical specimens derived from 199 liver cancer patients. We employed the Affymetrix Human Transcriptome Array 2.0 to examine transcriptome profiles. Unsupervised Consensus Clustering (cCluster), Subclass Mapping (SM) and Gene Set Enrichment Analysis (GSEA) algorithms were used to analyze transcriptome data. The results were validated in 247 Asian HCC cases and 104 Caucasian CCA cases. We found that the Thai HCC cases consisted of 3 stable subgroups (C1-C3), while the Thai CCA cases contained 4 stable subgroups (C1-C4) based on gene expression patterns determined by cCluster. SM analysis revealed that CCA-C1 and HCC-C1 subtypes shared a similar gene expression matrix, as did CCA-C2 and HCC-C2 for a separate pattern. Interestingly, patients in both CCA-C1 and HCC-C1 had a poor prognosis, while those in CCA-C2 and HCC-C2 had a good prognosis. These prognostic subtypes were validated in an independent Asian HCC cohort but not in a Caucasian CCA cohort. GSEA revealed that among 17 significantly altered canonical pathways in the C1 subtype, 8 are related to mitotic checkpoint signaling. In contrast, the main signaling pathways associated with the C2 subtype were related to cytokine and chemokine signaling. We found that certain mitotic checkpoint genes are highly activated only in C1, but not in the C2 subtype. These results are consistent with the hypothesis that CCA and HCC from Asian populations consist of molecularly-similar tumor subgroups with similar prognostic impacts and unique tumor biology and that the C1 subtype may be sensitive to mitotic checkpoint blockage. Our ability to rigorously classify and validate both HCC and CCA using these tools may represent a new avenue for the development of targeted therapeutic interventions.

Citation Format: The TIGER-LC Consortium, Jittiporn Chaisaingmongkol, Anuradha Budhu, Hien Dang, Siritida Rabibhadana, Benjarath Pupacdi, Marshonna Forgues, Vajarabhongsa Bhudhisawasdi, Nirush Lertprasertsuke, Anon Chotirosniramit, Chawalit Pairojkul, Chirayu U. Auewarakul, Thaniya Sricharunrat, Kannika Phornphutkul, Suleeporn Sangrajrang, Maggie Cam, Ping He, Stephen M. Hewitt, Xiaolin Wu, Snorri S. Thorgeirsson, Paul S. Meltzer, Christopher A. Loffredo, Robert H. Wiltrout, Curtis C. Harris, Chulabhorn Mahidol, Mathuros Ruchirawat, Xin W. Wang. The Thailand initiative in genomics and expression research for liver cancer (TIGER-LC): Defining novel subtypes of hepatocellular carcinoma and cholangiocarcinoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-173. doi:10.1158/1538-7445.AM2015-LB-173

Drimane Sesquiterpene-Conjugated Amino Acids from a Marine Isolate of the Fungus Talaromyces minioluteus (Penicillium Minioluteum)

Four new sesquiterpene lactones (3, 4, 6 and 7) and three known compounds, purpuride (1), berkedrimane B (2) and purpuride B (5), were isolated from the marine fungus, Talaromyces minioluteus (Penicillium minioluteum). New compounds were drimane sesquiterpenes conjugated with N-acetyl-l-valine, and their structures were elucidated by analysis of spectroscopic data, as well as by single crystal X-ray analysis. The isolated compounds could not inhibit the apoptosis-regulating enzyme, caspase-3, while three of the compounds (2, 3 and 7) exhibited weak cytotoxic activity.

Genotypic distribution of human papillomavirus (HPV) and cervical cytology findings in 5906 Thai women undergoing cervical cancer screening programs

Background

Cervical cancer is the major cause of morbidity and mortality in Thai women. Nevertheless, the preventive strategy such as HPV vaccination program has not been implemented at the national level. This study explored the HPV prevalence and genotypic distribution in a large cohort of Thai women.

Methods

A hospital-based cervical cancer screening program at Chulabhorn Hospital, Bangkok and a population-based screening program at a rural Pathum Thani Province were conducted using liquid-based cytology and HPV genotyping.

Results

Of 5906 women aged 20–70 years, Pap smear was abnormal in 4.9% and the overall HPV prevalence was 15.1%, with 6.4% high-risk (HR), 3.5% probable high-risk (PR), and 8.4% low-risk (LR) HPV. The prevalence and genotypic distribution were not significantly different between the two cohorts. Among HR-HPV genotypes, HPV52 was the most frequent (1.6%), followed by HPV16 (1.4%), HPV51 (0.9%), HPV58 (0.8%), HPV18 (0.6%), and HPV39 (0.6%). Among LR-HPV genotypes, HPV72 and HPV62 were the most frequent while HPV6 and HPV11 were rare. HPV infection was found to be proportionately high in young women, aged 20–30 years (25%) and decreasing with age (11% in women aged >50). The more severe abnormal cytology results, the higher positivity of HR-HPV infection was observed.

Conclusions

In conclusion, HPV52, HPV16, and HPV51 were identified as the most common HR-HPV genotypes in Thai women. This study contributes genotypic evidence that should be essential for the development of appropriate HPV vaccination program as part of Thailand’s cervical cancer prevention strategies.

Bioactive cardinane sesquiterpenes from the stems of Alangium salviifolium

A dichloromethane extract of the stems of Alangium salviifolium afforded twelve cardinane sesquiterpenes, seven of which are new alangenes A-G (1-7) and five known compounds (8-12). Their structures were elucidated on the basis of spectroscopic techniques including UV, IR, and NMR spectroscopies, and mass spectrometry. Most of the tested compounds exhibited very potent aromatase inhibition properties, especially in the case of the cardinane sesquiterpenes 1, 5-8, and 10 (IC50 values of 0.09, 0.13, 0.30, 0.06, 2.05, and 1.19 μM, respectively), which are significantly better than that of the positive control (ketoconazole, IC50 of 2.4 μM). Compounds 1 and 4 exhibited selective cytotoxicity against the MOLT-3 cancer cell line with IC50 values of 7.9 and 2.1 μg mL(-1) , respectively.

Cytotoxic metabolites from the endophytic fungus Penicillium chermesinum: discovery of a cysteine-targeted Michael acceptor as a pharmacophore for fragment-based drug discovery, bioconjugation and click reactions

A novel tetracyclic polyketide uniquely spiro-attached with a γ-lactone ring and a potent cytotoxic agent possessing a thiol-reactive pharmacophore were isolated from the mangrove endophytic fungus Penicillium chermesinum.

One strain-many compounds (OSMAC) method for production of polyketides, azaphilones, and an isochromanone using the endophytic fungus Dothideomycete sp

Polyketides 1-6 were produced by a one strain-many compounds (OSMAC) approach using the endophytic fungus Dothideomycete sp. CRI7 as a producer. Metabolite production of the fungus Dothideomycete sp. CRI7 was sensitive to sources of potato and malt extract used for the preparation of PDB and Czapek malt media, respectively. Three hitherto unknown metabolites were obtained from the fungus CRI7 grown in PDB medium prepared from a commercial potato powder instead of fresh tubers of potato, while three others were obtained from the fungus cultivated in Czapek malt medium. Moreover, a source of malt extract used in the Czapek malt medium was found to influence metabolite production by the fungus CRI7. Structure elucidation of these compounds was achieved by analysis of spectroscopic data, as well as by single crystal X-ray analysis. Two of the compounds showed weak cytotoxic activity, while the remainders were inactive toward the cell lines tested. One compound exhibited radical scavenging activity with an IC50 value of 21.7 μM, and inhibited aromatase with an IC50 value of 12.3 μM.

Effects of continuous intravenous infusion of morphine and morphine-tramadol on the minimum alveolar concentration of sevoflurane and electroencephalographic entropy indices in dogs

OBJECTIVE

To compare the effects of continuous rate infusions (CRIs) of intravenous (IV) morphine and morphine-tramadol on the minimum alveolar concentration (MAC) of sevoflurane, and on electroencephalographic entropy indices in dogs.

DESIGN

Prospective study.

ANIMALS

Eight young, healthy German shepherds, weighing 26.3 ± 3.1 kg (mean ± SD).

METHODS

Anaesthesia was induced and maintained with sevoflurane. A standard tail-clamp technique was used for MAC determination. Within one anaesthetic period, MAC was first determined during sevoflurane anaesthesia alone (MACB ); then during morphine infusion (MACM ), (loading dose 0.5 mg kg(-1) IM; CRI, 0.2 mg kg(-1 ) hour(-1)) then finally during morphine-tramadol infusion (tramadol loading dose 1.5 mg kg(-1) IV; CRI, 2.6 mg kg(-1)  hour(-1) ) (MACMT ). At each change, periods of 45 minutes were allowed for equilibration. Stated entropy (SE), response entropy (RE), and RE-SE differences were measured five minutes prior to and during tail clamping.

RESULTS

The MACB was 2.1 ± 0.3vol%. The morphine and morphine-tramadol infusions reduced MAC to 1.6 ± 0.3vol% and 1.3 ± 0.3vol%, respectively. MAC was decreased below baseline more during morphine-tramadol than during morphine alone (39 ± 9% versus 25 ± 6%, respectively; p = 0.003). All SE and RE and most RE-SE differences were increased significantly (p < 0.05) over pre-stimulation in all groups when the dogs responded purposefully to noxious stimulation. When no response to noxious stimulation occurred, the entropy indices did not change.

CONCLUSION AND CLINICAL RELEVANCE

In dogs, combined morphine-tramadol CRI decreased sevoflurane MAC more than morphine CRI alone. Entropy indices changed during nociceptive responses in anaesthetized animals, suggesting that entropy measurements may be useful in determining anaesthetic depth in dogs.

Recent investigations of bioactive natural products from endophytic, marine-derived, insect pathogenic fungi and Thai medicinal plants

Living organisms in Thailand are very diverse due to the unique geographical location of Thailand. The diversity of Thai bioresources has proven to be a rich source of biologically active compounds. The present review covers bioactive substances from Thai endophytic, marine-derived, insect pathogenic fungi and medicinal plants. Many new compounds isolated from Thai bioresources have diverse skeletons belonging to various classes of natural products. These compounds exhibited an array of biological activities, and some are of pharmaceutical interest. Bioactive compounds from Thai bioresources have not only attracted organic chemists to develop strategies for total synthesis, but also attracted (chemical) biologists to investigate the mechanisms of action. The chemistry and biology of some selected compounds are also discussed in this review.

α-Glucosidase inhibitory activities of isoflavanones, isoflavones, and pterocarpans from Mucuna pruriens

Three new isoflavanones (1-3) and thirteen known compounds (4-16) were isolated from the roots of Mucuna pruriens. The absolute configurations of isoflavanones 1-3 and parvisoflavanone (4), lespedeol C (5), and uncinanone C (6) were addressed by a circular dichroism technique. Isoflavanones, isoflavones, and pterocarpans of M. pruriens were found to be α-glucosidase inhibitors. Medicarpin (7) and parvisoflavone B (9) were potent α-glucosidase inhibitors (twofold less active than the standard drug acarbose). The production of bioactive metabolites in M. pruriens seems to be season-dependent.

Terpenoids from the roots of Drypetes hoaensis and their cytotoxic activities

Seven terpenoids consisting of five sesquiterpenoids, hoaensieremone, hoaensieremodione, hoaensifuranonal, hoaensieudesone, and hoaensibenzofuranal, and two friedelane triterpenoids, 3α-(E)-p-coumaroyloxyfriedelan-7-one and 3α-(E)-caffeoyloxyfriedelan-7-one were isolated from the dichloromethane extract of the roots of Drypetes hoaensis. Additionally, twelve known compounds and vanillin were isolated. Their structures were established on the basis of spectroscopic analysis, as well as by comparison with literature data. The anticancer activity of nine of these compounds was investigated.

An organocatalyst from renewable materials for the synthesis of coumarins and chromenes: three-component reaction and multigram scale synthesis

A new concept of catalysts which are prepared from renewable materials is demonstrated for the synthesis of coumarins and chromenes.

Lupane, friedelane, oleanane, and ursane triterpenes from the stem of Siphonodon celastrineus Griff

Twenty-one triterpenes consisting of a lupane derivative, two friedelanes, an oleanane derivative, and 17 ursane-type triterpenoids, together with three known triterpenes, three sterols, a fatty acid, a sesquiterpene alkaloid, and a glycerol derivative, were isolated from the stem of Siphonodon celastrineus. Their structures were characterized by various spectroscopic techniques, as well as comparison with literature data. Twenty-seven metabolites of these were evaluated for cytotoxic activity against six human cancer cell lines. The biosynthetic formation of a 1,4-dioxane bridge is also discussed.

Determination of arsenic species in rice from Thailand and other Asian countries using simple extraction and HPLC-ICP-MS analysis

Human exposure to arsenic (As) via rice consumption is of increasing concern. In the present study, the extraction and HPLC-ICP-MS analysis for As speciation in rice were investigated. A simple extraction with water and digestion with α-amylase followed by the analysis using ion-paring mode HPLC separation was developed. The method showed good extraction efficiencies (generally >80%) and column efficiencies (>90%) for rice samples. The optimization of mobile phase showed well separated peaks of As species. The limits of quantification (LOQ) of As(III), As(V), MMA, and DMA that were calculated based on sample mass were 1.6, 2.0, 2.0, and 1.6 μg kg(-1), respectively. A total of 185 rice samples (various types of rice) collected from different four regions in Thailand and some other Asian countries were analyzed. The total As and inorganic As in rice samples were in the ranges of 22.51-375.39 and 13.89-232.62 μg kg(-1), respectively. The estimated weekly intake of inorganic As from rice by Thai people accounted for 13.91-29.22% of the provisional tolerable weekly intake (PTWI).