Publications by authors named "Chee-Yan Choo"

Background: The burden of Human Papilloma Virus (HPV)-associated cancer remains high in developing nations.

Aims: To assess the impact of self-reported awareness and attitudes on vaccination practices, and the perception on self-sampling for cervical cancer screening.

Methods: A 12-month survey using purposive sampling of females attending an urban public university was conducted.

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The COVID-19 pandemic has tremendously increased the production and sales of disinfectants. This study aimed to systematically review and analyze the efficacy and safety of chlorine dioxide as a disinfectant. The literature relating to the use of chlorine dioxide as a disinfectant was systematically reviewed in January 2021 using databases such as PubMed, Science Direct, and Google Scholar.

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Common wheat (), one of the world's most consumed cereal grains, is known for its uses in baking and cooking in addition to its medicinal uses. As this plant's medical benefits are enormous and scattered, this narrative review was aimed at describing the pharmacological activities, phytochemistry, and the nutritional values of . It is a good source of dietary fiber, resistant starch, phenolic acids, alkylresorcinols, lignans, and diverse antioxidant compounds such as carotenoids, tocopherols and tocotrienols.

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Vitexin of Ficus deltoidea exhibits intestinal α-glucosidase inhibitory and blood glucose lowering effects. This study designs oral intestinal-specific alginate nanoparticulate system of vitexin. Nanospray-dried alginate, alginate/stearic acid and alginate-C18 conjugate nanoparticles were prepared.

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Labisia pumila var. alata (Myrsinaceae) or "Kacip fatimah" is a famous Malay traditional herb used for the maintenance of women's health. The extracts of L.

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Ethnopharmacological Relevance: The seeds of Brucea javanica and its aqueous decoction is a traditional medicine consumed by diabetic patients in Malaysia. The daily consumption of B. javanica seeds and it's aqueous decoction causes much concern as the quassinoids and its glycosides from the seeds exhibited various pharmacological activity at low doses.

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Bruceines D and E are quassinoids from seeds of Brucea javanica (L.) Merr. exhibiting hypoglycemia effect.

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A series of densely functionalized piperidine (FP) scaffolds was synthesized following a diastereoselective one-pot multicomponent protocol under eco-friendly conditions. The FPs were evaluated in vitro for their acetylcholinesterase (AChE) inhibitory activity, and in silico studies for all the target compounds were carried out using pharmacophore mapping, molecular docking and quantitative structure-activity relationship (QSAR) analysis in order to understand the structural features required for interaction with the AChE enzyme and the key active site residues involved in the intermolecular interactions. Halogenation, nitration or 3,4-methylenedixoxy-substitution at the phenyl ring attached to the 2- and 6-positions of 1,2,5,6-tetrahydropyridine nucleus in compounds 14-17, 19, 20, 24 and 26 greatly enhanced the AChE inhibitory activity.

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Eurycomanone and eurycomanol are two quassinoids from the roots of Eurycoma longifolia Jack. The aim of this study was to assess the bioactivity of these compounds in Jurkat and K562 human leukemia cell models compared to peripheral blood mononuclear cells from healthy donors. Both eurycomanone and eurycomanol inhibited Jurkat and K562 cell viability and proliferation without affecting healthy cells.

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Ficus deltoidea Jack (Moraceae) leaf extract is used as an antidiabetic in traditional medicine. Its widespread usage is reflected by the available preparations in the present commercial market. The efficacy of other Ficus species has not been entirely satisfactory and many antidiabetic herbs have demonstrated poor safety profiles.

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Ethnopharmacological Relevance: The seeds of Brucea javanica (L.) Merr (Simaroubaceae) are recommended by traditional practitioners for the treatment of diabetes mellitus.

Aim Of The Study: To identify the compounds responsible for blood glucose lowering effect and evaluate the acute toxicity of the compounds.

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The methanolic extract of the leaves of CASSIA ALATA was sequentially partitioned in increasing polarity to afford the hexane, chloroform, butanol and residual extract. Crude extracts were evaluated against MRSA using the agar well diffusion assay. The butanol and chloroform extracts both exhibited inhibition against MRSA with inhibition indexes of 1.

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Three new Lycopodium alkaloids, carinatumins A-C (1-3), have been isolated from the club moss Lycopodium carinatum. Structures and stereochemistry of 1-3 were elucidated on the basis of 2D NMR correlations. Carinatumins A (1) and B (2) exhibited a potent inhibitory activity against acetylcholinesterase.

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A cyclic octapeptide, cyclosquamosin B (2), isolated from the seeds of Annona squamosa showed a vasorelaxant effect on rat aorta. It showed a slow relaxation activity against norepinephrine (NE)-induced contractions of rat aorta with/without endothelium. It showed inhibition effect on vasocontraction of depolarized aorta with high concentration potassium, but moderately inhibition effect on NE-induced contraction in the presence of nicardipine.

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Two new cyclic peptides, dichotomins J (1) and K (2), have been isolated from the roots of Stellaria dichotoma, and their structures were elucidated by chemical degradation and extensive 2D NMR methods. Dichotomins J (1) and K (2) showed a moderate vasorelaxant effect on rat aorta.

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Among the quassinoids isolated from Eurycoma longifolia Jack, eurycomanone was identified as the most potent and toxic inhibitor of the chloroquine-resistant Gombak A isolate of Plasmodium falciparum. Several diacylated derivatives of eurycomanone, 1,15-di-O-isovaleryleurycomanone, 1,15-di-O-(3,3-dimethylacryloyl)- eurycomanone and 1,15-di-O-benzoyleurycomanone were synthesized by direct acylation with the respective acid chlorides. The monoacylated 15-O-isovaleryleurycomanone was synthesized by selective protection of the other hydroxy groups of eurycomanone with trimethylsilyl trifluoromethanesulphonate to enable the exclusive acylation of its C-15 hydroxy group.

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The roots of Eurycoma longifolia Jack have been used as traditional medicine to treat malaria. A systematic bioactivity-guided fractionation of this plant was conducted involving the determination of the effect of its various extracts and their chemical constituents on the lactate dehydrogenase activity of in vitro chloroquine-resistant Gombak A isolate and chloroquine-sensitive D10 strain of Plasmodium falciparum parasites. Their antiplasmodial activity was also compared with their known in vitro cytotoxicity against KB cells.

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The 50 % aqueous ethanol extract of Eurycoma longifolia Jack (Simaroubaceace) roots was partitioned with diethyl ether, n-butanol and then water. Acute toxicity studies of each fraction on mice administered orally and brine shrimps revealed that the n-butanol fraction was the most toxic. Toxicity-guided chromatographic fractionation of the n-butanol fraction identified eurycomanone as the most toxic component.

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A reversed phase-high performance liquid chromatography method with a photodiode array detector was developed for the simultaneous determination of three major alkaloids, 9-methoxycanthin-6-one (1), 3-methylcanthin-5,6-dione (2) and its 9-methoxy analogue (3) in Eurycoma longifolia Jack. These alkaloids were easily separated by a gradient elution protocol of 20 - 42 % acetonitrile in 0.1 % acetic acid.

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