A total of 126 food samples, categorised into three groups (seafood and seafood products, meat and meat products, as well as milk and dairy products) from Malaysia were analysed for polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). The concentration of PCDD/Fs that ranged from 0.16 to 0.25 pg WHO05-TEQ g(-1) fw was found in these samples. According to the food consumption data from the Global Environment Monitoring System (GEMS) of the World Health Organization (WHO), the dietary exposures to PCDD/F from seafood and seafood products, meat and meat products, as well as milk and dairy products for the general population in Malaysia were 0.064, 0.183 and 0.736 pg WHO05-TEQ kg(-1) bw day(-1), respectively. However, the exposure was higher in seafood and seafood products (0.415 pg WHO05-TEQ kg(-1) bw day(-1)) and meat and meat products (0.317 pg WHO05-TEQ kg(-1) bw day(-1)) when the data were estimated using the Malaysian food consumption statistics. The lower exposure was observed in dairy products with an estimation of 0.365 pg WHO05-TEQ kg(-1) bw day(-1). Overall, these dietary exposure estimates were much lower than the tolerable daily intake (TDI) as recommended by WHO. Thus, it is suggested that the dietary exposure to PCDD/F does not represent a risk for human health in Malaysia.
Phytochemical investigation on the stem bark of Shorea maxwelliana yielded five oligostilbenoids identified as α-viniferin (1), maximol A (2), vaticanol A (3), suffruticosol A (4) and vaticanol G (5). Chemotaxonomy of isolated compounds was discussed briefly. Major compounds were tested for neurotoxic and cytotoxic activities. Neurotoxicity for all tested compounds did not pose any toxic effect against cultured cell (cell viability range ±100-94%). Compounds 2-5 possessed active cyctotoxic activity against HL60 cell line with IC50 values range of 2.7-78 µg mL(-1).
Phytochemical investigation on Globba pendula resulted in the isolation of a new naturally occurring 16-oxo-(8)17-12-labdadien-15,11-olide 1 and benzofuran-2-carboxaldehyde 2. Other known compounds including isoandrographolide, indirubin, vanillin, vanillic acid, 2(3H)-benzoxazolone, as well as beta-sitosteryl-beta-D-glucopyranoside, beta-sitosterol, and 7alpha-hydroxysitosterol were also isolated. The structures were established based on spectroscopic data and comparison with the literature. Furthermore, the compound isoandrographolide has demonstrated strong cytotoxic properties towards a panel of cancer cell lines (MCF-7, PC-3, and H-460) with the IC50 values of 7.9, 8.7, and 9.0 microM, respectively.
Previously, several aurone derivatives were identified with promising neuroprotective activities. In developing these compounds to target the central nervous system (CNS), an assessment of their blood-brain barrier (BBB) permeability was performed using in vitro BBB models: parallel artificial membrane permeability assay-BBB which measures passive permeability and primary porcine brain endothelial cell model which enables determination of the involvement of active transport mechanism. Parallel artificial membrane permeability assay-BBB identified most compounds with high passive permeability, with 3 aurones having exceptional Pevalues highlighting the importance of basic amine moieties and optimal lipophilicity for good passive permeability. Bidirectional permeability assays with porcine brain endothelial cell showed a significant net influx permeation of the aurones indicating a facilitated uptake mechanism in contrast to donepezil, a CNS drug included in the evaluation which only displayed passive permeation. From pH-dependent permeability assay coupled with data analysis using pCEL-X software, intrinsic transcellular permeability (Po) of a representative aurone 4-3 was determined, considering factors such as the aqueous boundary layer that may hinder accurate in vitro to in vivo correlation. The Po value determined supported the in vivo feasibility of the aurone as a CNS-active compound.
Twenty derivatives of 5-aryl-2-(6'-nitrobenzofuran-2'-yl)-1,3,4-oxadiazoles (1-20) were synthesized and evaluated for their α-glucosidase inhibitory activities. Compounds containing hydroxyl and halogens (1-6, and 8-18) were found to be five to seventy folds more active with IC50 values in the range of 12.75±0.10-162.05±1.65μM, in comparison with the standard drug, acarbose (IC50=856.45±5.60μM). Current study explores the α-glucosidase inhibition of a hybrid class of compounds of oxadiazole and benzofurans. These findings may invite researchers to work in the area of treatment of hyperglycemia. Docking studies showed that most compounds are interacting with important amino acids Glu 276, Asp 214 and Phe 177 through hydrogen bonds and arene-arene interaction.
A series of novel aurones bearing amine and carbamate functionalities at various positions (rings A and/or B) of the scaffold was synthesized and evaluated for their acetylcholinesterase and butyrylcholinesterase inhibitory activities. Structure-activity relationship study disclosed several potent submicromolar acetylcholinesterase inhibitors (AChEIs) particularly aurones bearing piperidine and pyrrolidine moieties at ring A or ring B. Bulky groups particularly methoxyls, and carbamate to a lesser extent, at either rings were also prominently featured in these AChEI aurones as exemplified by the trimethoxyaurone 4-3. The active aurones exhibited a lower butyrylcholinesterase inhibition. A 3'-chloroaurone 6-3 originally designed to improve the metabolic stability of the scaffold was the most potent of the series. Molecular docking simulations showed these AChEI aurones to adopt favourable binding modes within the active site gorge of the Torpedo californica AChE (TcAChE) including an unusual chlorine-π interaction by the chlorine of 6-3 to establish additional bondings to hydrophobic residues of TcAChE. Evaluation of the potent aurones for their blood-brain barrier (BBB) permeability and metabolic stability using PAMPA-BBB assay and in vitro rat liver microsomes (RLM) identified 4-3 as an aurone with an optimal combination of high passive BBB permeability and moderate CYP450 metabolic stability. LC-MS identification of a mono-hydroxylated metabolite found in the RLM incubation of 4-3 provided an impetus for further improvement of the compound. Thus, 4-3, discovered within this present series is a promising, drug-like lead for the development of the aurones as potential multipotent agents for Alzheimer's disease.
The α-amylase acts as attractive target to treat type-2 diabetes mellitus. Therefore in discovering a small molecule as α-amylase inhibitor, we have synthesized benzofuran carbohydrazide analogs (1-25), characterized through different spectroscopic techniques such as 1HNMR and EI-MS. All screened analog shows good α-amylase inhibitory potentials with IC50 value ranging between 1.078±0.19 and 2.926±0.05µM when compared with acarbose having IC50=0.62±0.22µM. Only nine analogs among the series such as analogs 3, 5, 7, 8, 10, 12, 21, 23 and 24 exhibit good inhibitory potential with IC50 values 1.644±0.128, 1.078±0.19, 1.245±0.25, 1.843±0.19, 1.350±0.24, 1.629±0.015, 1.353±0.232, 1.359±0.119 and 1.488±0.07µM when compare with standard drug acarbose. All other analogs showed good to moderate α-amylase inhibitory potentials. The SAR study was conducted on the basis of substituent difference at the phenyl ring. The binding interaction between analogs and active site of enzyme was confirmed by docking studies.
A series of five new 2-(1-benzofuran-2-yl)-2-oxoethyl 4-(un/substituted)benzoates 4(a-e), with the general formula of C₈H₅O(C=O)CH₂O(C=O)C₆H₄X, X = H, Cl, CH₃, OCH₃ or NO₂, was synthesized in high purity and good yield under mild conditions. The synthesized products 4(a-e) were characterized by FTIR, ¹H-, (13)C- and ¹H-(13)C HMQC NMR spectroscopic analysis and their 3D structures were confirmed by single-crystal X-ray diffraction studies. These compounds were screened for their antimicrobial and antioxidant activities. The tested compounds showed antimicrobial ability in the order of 4b < 4a < 4c < 4d < 4e and the highest potency with minimum inhibition concentration (MIC) value of 125 µg/mL was observed for 4e. The results of antioxidant activities revealed the highest activity for compound 4e (32.62% ± 1.34%) in diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, 4d (31.01% ± 4.35%) in ferric reducing antioxidant power (FRAP) assay and 4a (27.11% ± 1.06%) in metal chelating (MC) activity.
A new tetramer oligostilbenoid possessing tetrahydrofuran ring, malaysianol C (1), was isolated from the acetone extract of the stem bark of Dryobalanops lanceolata, together with four known oligostilbenoids nepalensinol E (2), ϵ-viniferin (3), laevifonol (4), and ampelopsin F (5). The structures of isolated compounds were elucidated on the basis of spectral evidence. The antibacterial activity of the isolated compounds was evaluated using resazurin microtitre-plate assay, whereas the cytotoxic activity was tested using MTT assay. The plausible biogenetic routes of the isolated compounds are also discussed.
Four new 2,3-secodammarane triterpenoids, stellatonins A-D (3-6), together with a new 3,4-secodammarane triterpenoid, stellatonin E (7), and the known silvestrol (1), 5‴-episilvestrol (2), and β-sitosterol, were isolated from a methanol extract of the stems of Aglaia stellatopilosa through bioassay-guided fractionation. The structures of the new compounds were elucidated using spectroscopic and chemical methods. The compounds were evaluated for their cytotoxic activity against three human cancer cell lines and for their antimicrobial activity using a microtiter plate assay against a panel of Gram-positive and Gram-negative bacteria and fungi.
Recent developments in the target based cancer therapies have identified HSF1 as a novel non oncogenic drug target. The present study delineates the design and molecular docking evaluation of Rohinitib (RHT) - Cantharidin (CLA) based novel HSF1 inhibitors for target-based cancer therapy. Here, we exploited the pharmacophoric features of both the parent ligands for the design of novel hybrid HSF1 inhibitors. The RHT-CLA ligands were designed and characterized for ADME/Tox features, interaction with HSF1 DNA binding domain and their pharmacophoric features essential for interaction. From the results, amino acid residues Ala17, Phe61, His63, Asn65, Ser68, Arg71 and Gln72 were found crucial for HSF1 interaction with the Heat shock elements (HSE). The hybrid ligands had better affinity towards the HSF1 DNA binding domain, in comparison to RHT or CLA and interacted with most of the active site residues. Additionally, the HSF1-ligand complex had a reduced affinity towards HSE in comparison to native HSF1. Based on the results, ligand RC15 and RC17 were non carcinogenic, non mutagenic, completely biodegradable under aerobic conditions, had better affinity for HSF1 (1.132 and 1.129 folds increase respectively) and diminished the interaction of HSF1 with HSE (1.203 and 1.239 folds decrease respectively). The simulation analysis also suggested that the ligands formed a stable complex with HSF1, restraining the movement of active site residues. In conclusion, RHT-CLA hybrid ligands can be used as a potential inhibitor of HSF1 for non-oncogene target based cancer therapy.
Previously, a series of aurones bearing amine and carbamate functionalities was synthesized and evaluated for their cholinesterase inhibitory activity and drug-like attributes. In the present study, these aurones were evaluated for their multi-targeting properties in two Alzheimer's disease (AD)-related activities namely, monoamine oxidase (MAO) and amyloid-beta (Aβ) inhibition. Evaluation of the aurones for MAO inhibitory activity disclosed several potent selective inhibitors of MAO-B, particularly those with 6-methoxyl group attached at ring A. Of the different amine moieties attached as side chains, pyrrolidine-bearing aurones were prominent as represented by 2-2, the most potent inhibitor. Evaluation on the Aβ aggregation inhibition identified 4-3 as the best inhibitor with a percentage inhibition comparable to that of a known Aβ inhibitor curcumin. Examination on the neuroprotective ability of the more drug-like aurone 4-3 in two Caenorhabditis elegans neurodegeneration models showed 4-3 to protect the nematodes against both Aβ- and 6-hydroxydopamine-induced toxicities. These new activities further support 4-3 as a promising lead to develop the aurones as potential multipotent agents for neurodegenerative diseases.
Goniothalamus macrophyllus (Blume) Hook. f. & Thoms. is a plant widely distributed in Malaysia. The aim of this study is to identify compounds from the roots of G. macrophyllus. The ground roots were extracted with aqueous methanol and partitioned sequentially with n-hexane, chloroform and butanol. Purification from this extracts afforded six compounds with two new compounds, namely goniolandrene-A (1), -B (2). The absolute configuration of goniolandrene B (2) was established by circular dichrosim. The compounds were cytotoxic against the P388 cells with IC50 values ranging from 0.42 to 160 μM. Goniothalamin (3) exhibited the highest inhibition of 0.42 μM.