Publications by authors named "Kae Shin Sim"

Kaempferia parviflora or commonly known as "Kunyit hitam" by locals, is an edible plant, native to tropical regions, has been extensively utilized for culinary and medicinal applications. The present study aimed to investigate the phytochemical composition and biological activities of the rhizomes of K. parviflora.

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A new probe, 4-(((3',6'-bis(diethylamino)-3-oxospiro[isoindoline-1,9'-xanthen]-2-yl)imino)methyl)phenyl)boronic acid (R4B) was prepared by facile condensation of 4-formylphenylboronic acid and rhodamine B hydrazide. R4B was characterized by spectroscopic methods and single crystal X-ray diffraction. The sensor R4B solution turned pink and emitted orange fluorescence only in the presence of sialic acid but remained colorless and non-fluorescent otherwise.

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A new series of indolenines decorated with pyrazolo[3,4-b]pyridines were designed and synthesized in up to 96% yield from the acid-catalyzed cyclocondensation of 1,3-dialdehydes with 3-aminopyrazoles. X-ray crystallography on a representative derivative, 5n, revealed two close to planar conformations whereby the N-atom of the pyridyl residue was syn or anti to the pyrrole-N atom in the two independent molecules of the asymmetric unit. The computational and DNA binding data suggest that 5n is a strong DNA intercalator with the results in agreement with its potent cytotoxicity against two colorectal cancer cell lines (HCT 116 and HT-29).

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Nine new alkaloids, eugeniinalines A-H (-) and (+)-eburnamenine -oxide (), comprising one quinoline, six indole, and two isogranatanine alkaloids, were isolated from the stem-bark extract of the Malayan . The structures and absolute configurations of these alkaloids were established based on the analysis of the spectroscopic data, GIAO NMR calculations, DP4+ probability analysis, TDDFT-ECD method, and X-ray diffraction analysis. Eugeniinaline A () represents a new pentacyclic quinoline alkaloid with a 6/6/5/6/7 ring system.

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Essential oils have been recognised for their potential benefits in oral care. The aim of this study was to evaluate the antibacterial and antiproliferative activity of essential oils derived from four Zingiberaceae species. A combination of GC/MS and GC-FID was employed to analyse these essential oils.

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Five new compounds of benz[e]indole pyrazolyl-substituted amides (2a-e) were synthesised in low to good yields via the direct amide-coupling reaction between a pyrazolyl derivative containing a carboxylic acid and several amine substrates. The molecular structures were determined by various spectroscopic methods, such as NMR (H, C and F), FT-IR and high-resolution mass spectrometry (HRMS). X-ray crystallographic analysis on the 4-fluorobenzyl derivative (2d) reveals the amide-O atom to reside to the opposite side of the molecule to the pyrazolyl-N and pyrrolyl-N atoms; in the molecular packing, helical chains feature amide-N‒H⋯N(pyrrolyl) hydrogen bonds.

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Eight undescribed iboga alkaloids, polyneurines A-H, were isolated from the bark of Tabernaemontana polyneura. The structures of these alkaloids were established by interpretation of the MS and NMR data, while the configurations were determined using GIAO NMR calculations and DP4+ probability analysis, TDDFT-ECD method, or X-ray diffraction analysis. Polyneurine A possesses a γ-lactone unit embedded within the iboga skeleton, while polyneurines D and E incorporate a formylmethyl moiety at C-3 of the iboga skeleton.

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Neurological diseases are increasingly recognized as a health burden worldwide, mainly affecting the elderly population. Sanguinoderma rugosum (=Amauroderma rugosum) is a wild medicinal mushroom traditionally used to alleviate inflammation and prevent seizures. The present study aimed to investigate the neuroprotective and neurorescue effects as well as the possible mechanisms of S.

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Article Synopsis
  • Two compounds, 16'-decarbomethoxyvoacamine (1) and 16'-decarbomethoxydihydrovoacamine (2), showed strong anti-cancer effects on human colorectal adenocarcinoma HT-29 cells while sparing normal cells (CCD-18Co).
  • Both compounds halted cancer cell growth by causing G0/G1 cell cycle arrest and triggering mitochondrial apoptosis, but compound 2 displayed greater potency and was selected for further study.
  • In additional tests, compound 2 inhibited the formation of tumor-like cell aggregates and was found to stabilize microtubules, potentially binding to a specific site and generating reactive oxygen species (ROS) that activate cell cycle
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A new chemosensor 1 was synthesized by reacting rhodamine B hydrazide and 2,3,4-trihydroxybenzaldehyde, which was then characterized by spectroscopic techniques and single crystal X-ray crystallography. Sensor 1 has the ability to sense Co/Cu ions by "naked-eye" with an apparent colour change from colourless to pink in different solvent system, MeCN and DMF respectively. Furthermore, it can selectively detect Co/Cu among wide range of different metal ions, and it exhibits low detection limit of 4.

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A new linearly fused macroline-sarpagine bisindole, angustilongine M (), was isolated from the methanolic extract of . The structure of the alkaloid was elucidated based on analysis of the spectroscopic data, and its biological activity was evaluated together with another previously reported macroline-akuammiline bisindole from the same plant, angustilongine A (). Compounds and showed pronounced in vitro growth inhibitory activity against a wide panel of human cancer cell lines.

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Background: The Asiatic pit vipers from the complex are medically important venomous snakes. These pit vipers are often associated with snakebite that leads to fatal coagulopathy and tissue necrosis. The cytotoxic venoms of spp.

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Two new Schiff base ligands (TE and TF) were prepared from conjugation of testosterone with 4-(4-ethylphenyl)-3-thiosemicarbazide and 4-(4-fluorophenyl)-3-thiosemicarbazide, respectively. Their nickel (NE and NF) and zinc (ZE and ZF) complexes were reported. X-ray crystallography revealed a distorted square planar geometry was adopted by NE.

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A methanol extract of the stem bark of the Malayan provided seven new bisindole alkaloids, comprising six macroline-sarpagine alkaloids (angustilongines E-K, -) and one macroline-pleiocarpamine bisindole alkaloid (angustilongine L, ). Analysis of the spectroscopic data (NMR and MS) of these compounds led to the proposed structures of these alkaloids. The macroline-sarpagine alkaloids (-) showed in vitro growth inhibitory activity against a panel of human cancer cell lines, inclusive of KB, vincristine-resistant KB, PC-3, LNCaP, MCF7, MDA-MB-231, HT-29, HCT 116, and A549 cells (IC values: 0.

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An ecologically important tropical freshwater microalga, , was exposed to Ni toxicity under two temperature regimes, 25 and 35 °C to investigate the interactive effects of warming and different Ni concentrations (0.1, 1.0 and 10.

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Three new alkaloids were isolated from the bark extract of the Malayan , viz., arbophyllidine (), an unusual pentacyclic, monoterpenoid indole characterized by an absence of oxygen atoms and incorporating a new carbon-nitrogen skeleton, and arbophyllinines A () and B (), two pentacyclic corynanthean alkaloids incorporating a hydroxyethyl-substituted tetrahydrofuranone ring. The structures of the alkaloids were deduced based on analysis of the MS and NMR data and confirmed by X-ray diffraction analyses.

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Examination of the EtOH extract of the leaves of the Malayan Tabernaemontana corymbosa resulted in the isolation of four new (1-4) and two known bisindole alkaloids (5, 6) of the Aspidosperma- Aspidosperma type. The structures of these alkaloids were determined based on analysis of the spectroscopic data (NMR and HRESIMS). X-ray diffraction analyses of the related bisindole alkaloids conophylline (5) and conophyllinine (6) established the absolute configurations.

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Five culinary-medicinal mushrooms are commonly available in the Malaysian market: Agaricus bisporus (white and brown), Ganoderma lucidum, Hypsizygus marmoreus, Pleurotus floridanus, and P. pulmonarius. These species were selected for use in the current study, the aim of which was to investigate the antimelanogenesis and anti-inflammatory activity of these mushrooms in an attempt to evaluate their potential use in cosmeceuticals.

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Examination of the EtOH extract of the Malayan Alstonia penangiana resulted in the isolation of 10 new alkaloids, comprising two ajmaline (1, 2), four macroline oxindole (3-6), and four macroline-akuammiline bisindole alkaloids (7-10). The structures of these alkaloids were determined based on analysis of the spectroscopic data and, in the case of the oxindole 6 and the bisindole alkaloid 7, also confirmed by X-ray diffraction analysis. The bisindole alkaloids 7 and 8 showed pronounced in vitro growth inhibitory activity against an array of human cancer cell lines, including KB, vincristine-resistant KB, PC-3, LNCaP, MCF7, MDA-MB-231, HT-29, HCT 116, and A549 cells with IC values in the 0.

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Physiochemical changes, including size, are known to affect gold nanoparticle cellular internalization and treatment efficacy. Here, we report the effect of four sizes of cystine/citric acid-coated confeito-like gold nanoparticles (confeito-AuNPs) (30, 60, 80 and 100nm) on cellular uptake, intracellular localization and photothermal anticancer treatment efficiency in MDA-MB231 breast cancer cells. Cellular uptake is size dependent with the smallest size of confeito-AuNPs (30nm) having the highest cellular internalization via clathrin- and caveolae-mediated endocytosis.

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The active isolate of LF1 in Leptospermum javanicum was further looked into its capabilities in provoking an apoptotic reaction and suppressing the metastasis process in treated non-small lung cancer cells. LF1 underwent isolation and purification to yield a white powder which was identified as Betulinic acid (BA) via NMR, LCMS and IR spectroscopy. The isolate, BA, which produced an encouraging cytotoxic effect against non-small lung cancer cells (A549 and NCI-H1299) through the MTT assay, was further assessed with TUNEL, Sub-G1 population quantification, acridine orange/ethidium bromide staining as well as activated caspase-3 detection.

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This study aims to investigate the mechanisms associated with the antiproliferation effect of guanosine on human colon carcinoma HCT 116 cells. In this study, guanosine induced more drastic cell cycle arrest effect than cell death effect on HCT 116 cells. The cell cycle arrest effect of guanosine on HCT 116 cells appeared to be associated with the increased activation of mitogen-activated protein kinases (MAPK) such as ERK1/2, p38 and JNK.

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Examination of the EtOH extract of the Malayan Tabernaemontana corymbosa resulted in the isolation of three new alkaloids, viz., cononuridine (1), an unusual hexacyclic, iboga-derived, monoterpenoid indole characterized by contraction of the tetrahydroazepine C-ring and incorporation of an additional isoxazolidine ring, taberisidine (2), a seco-corynanthean alkaloid, and conofolidine (3), an Aspidosperma-Aspidosperma bisindole that showed pronounced in vitro growth inhibitory activity against an array of human cancer cell lines, including KB, vincristine-resistant KB, PC-3, LNCaP, MCF7, MDA-MB-231, HT-29, and HCT 116 cells. The structures and absolute configurations of 1 and 3 and the absolute configuration of the novel pyridopyrimidine indole alkaloid vernavosine (4) were confirmed by X-ray diffraction analysis.

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Background: Thiosemicarbazone (TSC) is a Schiff base that has been receiving considerable attention owing to its promising biological implication and remarkable pharmacological properties. The most promising drug candidate of this class would be Triapine (3-aminopyridine-2-carboxaldehyde thiosemicarbazone) which has entered phase II clinical trials as a potent anti-cancer chemotherapeutic agent.

Objective: The current research aimed to synthesize several Schiff base ligands from (3-formyl-4-hydroxyphenyl) methyltriphenylphosphonium (T).

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Six new bisindole alkaloids of the iboga-vobasine type, vobatensines A-F (1-6), in addition to four known bisindoles (8-11), were isolated from a stem bark extract of a Malayan Tabernaemontana corymbosa. The structures of these alkaloids were determined based on analysis of the spectroscopic data and in the case of vobatensines A (1), B (2), and 16'-decarbomethoxyvoacamine (8) also confirmed by partial syntheses. Nine of these alkaloids (1-5, 8-11) showed pronounced in vitro growth inhibitory activity against human KB, PC-3, LNCaP, HCT 116, HT-29, MCF7, MDA-MB-231, and A549 cancer cells.

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