Puttinan Meepowpan

In vitro screening for anthelmintic and antitumour activity of ethnomedicinal plants from Thailand.

AIM OF STUDY This study screened for anthelmintic and/or antitumour bioactive compounds from Thai indigenous plants and evaluated effectiveness against three different worm species and two cancer cell lines. MATERIALS AND METHODS Methylene chloride and methanol extracts of 32 plant species were screened for in vitro anthelmintic activity against three species of worms, the nematode Caenorhabditis elegans, the digeneans Paramphistomum epiclitum and Schistosoma mansoni (cercariae). Cytotoxicity of the extracts was evaluated against two cancer cell lines: human amelanotic melanoma (C32) and human cervical carcinoma (HeLa) by the SRB assay. Anthelmintic and anticancer activities were evaluated by the inhibiting concentration at 50% death (IC(50)) and the selectivity index (SI) relative to human fibroblasts. RESULTS AND CONCLUSIONS None of the extracts were active against Paramphistomum epiclitum. Plumbagin, a pure compound from Plumbago indica, had the strongest activity against Caenorhabditis elegans. The methylene chloride extract of Piper chaba fruits had the strongest activity against schistosome cercariae. Strong cytotoxicity was shown by the methylene chloride extract of Michelia champaca bark and the methanol extract of Curcuma longa rhizome against C32 and HeLa, respectively. These extracts had higher SI (>100) than positive controls in relation to either the worms or the cell lines. The methanol extract of Bouea burmanica had a slightly lower activity towards C32 cells than did Michelia champaca but had a much higher SI (>27,000). ETHNOPHARMACOLOGICAL RELEVANCE The plant species screened in this research was recorded by several indigenous medicinal practitioners as antiparasitic, anticancer and/or related activities to the human major organ system.

Sulfonation of papain treated chitosan and its mechanism for anticoagulant activity

The novel low-molecular-weight chitosan polysulfate (MW 5120-26,200 Da) was prepared using the depolymerization of chitosan with papain (EC. 3.4.22.2). The sulfonation of depolymerized products was performed using chlorosulfonic acid in N,N-dimethylformamide under semi-heterogeneous conditions. The structures of the products were characterized by FTIR, (13)C NMR, and (1)H NMR (1D, 2D NMR) spectroscopy. The present study sheds light on the mechanism of anticoagulant activity of chitosan polysulfate. Anticoagulant activity was investigated by an activated partial thromboplastin assay, a thrombin time assay, a prothrombin time assay, and thrombelastography. Surface plasmon resonance also provided valuable data for understanding the relationship between the molecular binding of sulfated chitosan to two important blood clotting regulators, antithrombin III and heparin cofactor II. These results show that the principal mechanism by which this chitosan polysulfate exhibits anticoagulant activity is mediated through heparin cofactor II and is dependent on polysaccharide molecular weight.

Antiproliferative effect of alkaloids via cell cycle arrest from Pseuduvaria rugosa.

Context: Pseuduvaria rugosa (Blume) Merr. (Annonacaea) grows widely in the south and southeast regions of Thailand. Preliminary screening for biological activities revealed that crude hexane, ethyl acetate, and acetone extracts from mixtures of leaves and twigs of P. rugosa showed cytotoxicity. Objective: Chemical constituents and their antiproliferative activity in K562, U937, and HL-60 human leukemic cell lines from P. rugosa were performed for the first time. Materials and methods: The isolated compounds were obtained from chromatographic separation. The structures were established by spectroscopic techniques including IR, UV, NMR together with 2D NMR (HMBC, COSY, and NOE) and MS. The K562, U937, and HL-60 cell lines were treated with isolated aporphine alkaloids (0–100 µg/mL) and cell viability was measured with the MTT assay. Cell cycle analysis was performed using propidium iodide (PI) based staining methods. Results: Two known aporphine alkaloids, 1,2,3-trimethoxy-5-oxonoraporphine (1) and ouregidione (2) were isolated. Treatment of the cells with compounds 1 and 2 at a concentration of 100 µg/mL for 72 h reduced the viability of K562, U937, and HL-60 cell lines to 63 and 64, 38 and 66, and 49 and 64%, respectively. In addition, compounds 1 and 2, at a concentration of 100 µg/mL, exposed to U937 and HL-60 cell lines showed cell cycle arrest. The U937 cell line treated with compounds 1 and 2 increased significantly the proportion of the cell in S phase, whereas the HL-60 cell line-induced G2/M and G1 phase, respectively. Discussion and conclusion: The results showed that 1,2,3-trimethoxy-5-oxonoraporphine and ouregidione-induced cytotoxicity with HL-60, U937, and K562 cells where 1,2,3-trimethoxy-5-oxonoraporphine was more active than ouregidione.

Theoretical investigation on the mechanism and kinetics of the ring-opening polymerization of ε-caprolactone initiated by tin(II) alkoxides

A theoretical investigation of the ring-opening polymerization (ROP) mechanism of ε-caprolactone (CL) with tin(II) alkoxide, Sn(OR)2 initiators (R = n-C4H9, i-C4H9, t-C4H9, n-C6H13, n-C8H17) was studied. The density functional theory at B3LYP level was used to perform the modeled reactions. A coordination-insertion mechanism was found to occur via two transition states. Starting with a coordination of CL onto tin center led to a nucleophilic addition of the carbonyl group of CL, followed by the exchange of alkoxide ligand. The CL ring opening was completed through classical acyl-oxygen bond cleavage. The reaction barrier heights of ε-caprolactone with different initiators were calculated using potential energy profiles. The reaction of ε-caprolactone with Sn(OR)2 having R = n-C4H9 has the least value of barrier height compared to other reactions. The rate constants for each reaction were calculated using the transition state theory with TheRATE program. The rate constants are in good agreement with available experimental data.

Genotoxicity and antigenotoxicity of the methanol extract of Cleistocalyx nervosum var. paniala seed using a Salmonella mutation assay and rat liver micronucleus tests

Clesitocalyx nervosum var. paniala, an edible fruit found in some parts of Southeast Asia including Thailand, contains high amounts of polyphenols and has multiple biological activities. The purposes of this study were to evaluate the genotoxic and antigenotoxic effects of methanol extracts of C. nervosum seeds via a Salmonella mutation assay and a rat liver micronucleus test. C. nervosum extract was not mutagenic to Salmonella typhimurium strains TA98 and TA100 in both the presence and absence of metabolic activation. Furthermore, C. nervosum seed extract presented antigenotoxicity against aflatoxin B1, MeIQ and AF-2 induced mutagenesis. Clastogenicity and anticlastogenicity of C. nervosum seed extracts were determined in rat livers. Male wistar rats were divided into 6 groups. Groups 1 and 3 were treated with 5% tween-80 as a vehicle control. Group 2 received 1,000 mg/kg bw of methanol seed extract and groups 4–6 were fed with 20, 100 and 1,000 mg/kg bw of seed extracts, respectively for 21 days. At day 15 and 18 of the experiment, treated rats in groups 3–6 were intraperitoneally injected with 30 mg/kg bw of diethylnitrosamine to initiate hepatocarcinogenesis. At day 22, all rats were partially hepatectomized to amplify mutated hepatocytes. C. nervosum seed extract did not affect micronucleus formation in rat livers, but did slightly decrease the frequencies of micronucleated hepatocytes of diethylnitrosamine treated rats. In conclusion, the methanol extract of C. nervosum seed may contain chemopreventive compounds against carcinogenesis.

Aristolactam-type alkaloids from orophea enterocarpa and their cytotoxicities

A new aristolactam, named enterocarpam-III (10-amino-2,3,4,6-tetramethoxy phenanthrene-1-carboxylic acid lactam, 1) together with the known alkaloid stigmalactam (2), were isolated from Orophea enterocarpa. Their structures were elucidated on the basis of interpretation of their spectroscopic data. Compounds 1 and 2 exhibited significant cytotoxicities against human colon adenocarcinoma (HCT15) cell line with IC50 values of 1.68 and 1.32 μM, respectively.

Effect of topology of poly(L-lactide-co-ε-caprolactone) scaffolds on the response of cultured human umbilical cord Wharton’s jelly-derived mesenchymal stem cells and neuroblastoma cell lines

In this study, for the first time, a biodegradable poly(L-lactide-co-ε-caprolactone), PLC 67:33 copolymer was developed for use as temporary scaffolds in reconstructive nerve surgery. The effect of the surface topology and pore architecture were studied on the biocompatibility for supporting the growth of human umbilical cord Wharton’s jelly-derived mesenchymal stem cells (hWJ-MSCs) and human neuroblastoma cells (hNBCs) as cell models. Porous PLC membranes were prepared by electrospinning and phase immersion precipitation with particulate leaching and nonporous PLC membranes were prepared by solvent casting. From the results, the porous PLC membranes can support hWJ-MSCs and hNBCs cells better than the nonporous PLC membrane, and the interconnected pore scaffold prepared by electrospinning exhibited a more significant supporting attachment of the cells than the open pore and nonporous membranes. We can consider that these electrospun PLC membranes with 3-D interconnecting fiber networks and a high porosity warrant a potential use as nerve guides in reconstructive nerve surgery.

Rapid activity prediction of HIV-1 integrase inhibitors: harnessing docking energetic components for empirical scoring by chemometric and artificial neural network approaches

Improving performance of scoring functions for drug docking simulations is a challenging task in the modern discovery pipeline. Among various ways to enhance the efficiency of scoring function, tuning of energetic component approach is an attractive option that provides better predictions. Herein we present the first development of rapid and simple tuning models for predicting and scoring inhibitory activity of investigated ligands docked into catalytic core domain structures of HIV-1 integrase (IN) enzyme. We developed the models using all energetic terms obtained from flexible ligand-rigid receptor dockings by AutoDock4, followed by a data analysis using either partial least squares (PLS) or self-organizing maps (SOMs). The models were established using 66 and 64 ligands of mercaptobenzenesulfonamides for the PLS-based and the SOMs-based inhibitory activity predictions, respectively. The models were then evaluated for their predictability quality using closely related test compounds, as well as five different unrelated inhibitor test sets. Weighting constants for each energy term were also optimized, thus customizing the scoring function for this specific target protein. Root-mean-square error (RMSE) values between the predicted and the experimental inhibitory activities were determined to be <1 (i.e. within a magnitude of a single log scale of actual IC50 values). Hence, we propose that, as a pre-functional assay screening step, AutoDock4 docking in combination with these subsequent rapid weighted energy tuning methods via PLS and SOMs analyses is a viable approach to predict the potential inhibitory activity and to discriminate among small drug-like molecules to target a specific protein of interest.Graphical Abstract

Influence of Molecular Weight on the Non-Isothermal Melt Crystallization of Biodegradable Poly(D-Lactide)

The influence of molecular weight of poly (D-lactide) (PDL) on the melt crystallization was successfully investigated by non-isothermal differential scanning calorimetry (DSC) technique. The synthesized PDLs with three different number average molecular weights (Mn) of 2.39×105 (PDL1), 1.09×105 (PDL2) and 0.61×105 (PDL3) were utilized in this study. From DSC kinetics analysis, it was found that the rate of PDLs crystallization increased with increasing cooling rate. Furthermore, the crystallization rate of PDLs was dependent on molecular weight and determined to be in the following order: PDL3 > PDL2 > PDL1. The crystallization mechanism was analyzed by the Avrami, Ozawa and Liu models. The mechanism of all PDLs crystallization was nucleation with three dimensional growths. Furthermore, the molecular weight of PDLs affected not only the crystallization rate but also the thermal property. As the molecular weight of PDLs increased, the melting temperature (Tm) increased but the heat of melting (∆Hm) decreased.

Flavones from Aerial Parts of Polyalthia bullata and Cytotoxicity Against Cancer Cell Lines

Polyalthia bullata King is a flowering plant in the Annonaceae family. It is widely distributed in the Indian subcontinent and Malay peninsula [1]. Previous chemical investigations of the stem bark of P. bullata displayed two new bisdehydroaporphines and three known aporphine alkaloids [1]. This plant has been used as a traditional medicine in Malaysia, such as a general tonic for men and for the treatment of skin problems, high blood pressure, diabetes, and liver diseases [2]. Due to its value as a traditional medicine and the fact that there are few reports on P. bullata, this research aims to investigate the chemical constituents of this plant and their biological activities. The phytochemical investigations from the aerial parts of P. bullata led to the isolation of three known flavones (1–3). All compounds were evaluated for their cytotoxicities against six cancer cell lines using the standard in vitro sulforhodamine B (SRB) assay in 96-well plates [3]. The results demonstrated that compound 3 from the EtOAc extract showed some anticancer activity against P-388 and MCF-7 cell lines with ED50 values of 7.13 and 18.16 g/mL, respectively. To the best of our knowledge, this is the first report on the isolated flavones of this plant and their biological activities. In addition, all compounds are reported for the first time from Polyalthia genus.