Gwendoline Cheng Lian Ee

Universiti Putra Malaysia

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Soek Sin Teh

Malaysian Palm Oil Board

Siau Hui Mah

Taylor's University

Mawardi Rahmani

Universiti Putra Malaysia

Mohd Aspollah Sukari

Universiti Putra Malaysia

Yun Hin Taufiq‐Yap

Universiti Putra Malaysia

Vivien Yi Mian Jong

Universiti Teknologi MARA

Rusea Go

Universiti Putra Malaysia

Najihah Mohd Hashim

International Islamic University Malaysia

M. Rahmani

Ahl Al Bayt University

Shaari Daud

Universiti Teknologi MARA

Cooperative Institutions

Universiti Putra Malaysia

123

Serdang Hospital

University of Malaya

National University of Malaysia

Universiti Sains Malaysia

Universiti Teknologi MARA

International Islamic University Malaysia

Universiti Tunku Abdul Rahman

National University of Singapore

Forest Research Institute Malaysia

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12-Acetyl-6-hydroxy-3,3,9,9-tetramethylfuro[3,4-b]pyrano[3,2-h]xanthene-7,11(3H,9H)-dione

Acta Crystallographica Section E Structure Reports Online (2010)

Gwendoline Cheng Lian Ee Siow Hwa Teo Huey Chong Kwong Mohamed Ibrahim Mohamed Tahir Sidik Silong

The title compound, Artonol B, C(24)H(20)O(7), isolated from the stem bark of Artocarpus kemando, consists of four six-membered rings and one five-membered ring. The tricyclic xanthone ring system is almost planar [maximum deviation 0.115 (5) Å], whereas the pyran-oid ring is in a distorted boat conformation·The furan ring is almost coplanar with the fused aromatic ring, making a dihedral angle of 3.76 (9)°. The phenol ring serves as a intra-molecular hydrogen-bond donor to the adjacent carbonyl group and also acts as an inter-molecular hydrogen-bond acceptor for the methyl groups of adjacent mol-ecules, forming a three-dimensional network in the crystal.

Xanthene

10.1107/s1600536810048592

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Citations (1)

A New Pyranoxanthone from the Stem Bark of Calophyllum inophyllum

Letters in Organic Chemistry (2011)

Siau Hui Mah Gwendoline Cheng Lian Ee Mawardi Rahmani Yun Hin Taufiq‐Yap Rusea Go

The stem bark of Calophyllum inophyllum gave one new prenylated dipyranoxanthone inophinone (1), together with two other xanthones, inophyllin A (2) and caloxanthone B (3) and three common triterpenes, friedelin (4), stigmasterol (5) and betulinic acid (6). 1D and 2D NMR spectral data (1H, 13C, DEPT, COSY, HMBC & HMQC) were used to elucidate the structures of these compounds Keywords: Inophinone, dipyranoxanthone, Calophyllum inophyllum, Guttiferae, xanthones, inophyllin, caloxanthone, triterpenes, friedelin, stigmasterol

Friedelin

Betulinic acid

Stigmasterol

Terpene

DEPT

Xanthone

10.2174/157017811796064430

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Antileukemic activity and chemical constituents of some Zingiberaceae species.

Asian Journal of Chemistry (2010)

Mohd Aspollah Sukari Sook Wah Tang Bee Keat Neoh Gwendoline Cheng Lian Ee Mawardi Rahmani

Crude extracts of various solvents from six species (genus Alpinia, Zingiber, Kaempferia) of Zingiberaceae family have been chosen for the in vitro cytotoxic activity screening against the inhibition of HL-60 cell line (Human promyelocytic leukemia). Eight extracts (44 %) were found to have cytotoxic activity with IC50 values less than 30 μg/mL, with Alpinia galanga showing the most prominent antileukemic activity. Further isolation work on Kaempferia galanga has yielded ethyl p-methoxy-trans-cinnamate (1), p-methoxy-trans-cinnamic acid (2) besides b-sitosterol.

Zingiberaceae

Cinnamic acid

Diarylheptanoids

Alpinia

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Green water-dispersible coarse powder nano-formulation for allelopathic leaf extract of Mikania micrantha Kunth ex H.B.K. in controlling the rice weed Echinochloa colona (L.) Link

Industrial Crops and Products (2022)

Chaw Jiang Lim Chan Lim Mahashanon Arumugam Gwendoline Cheng Lian Ee Dzolkhifli Omar

Allelopathy

Mikania micrantha

10.1016/j.indcrop.2022.115468

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ENZYMATIC SYNTHESIS AND CHARACTERIZATION OF PALM-BASED KOJIC ACID ESTER

Noor Hayati Khamaruddin Mahiran Basri Gwendoline Cheng Lian Ee Abu Bakar Salleh Raja Noor Zaliha Raja Abd Rahman

Kojic acid ester was synthesized from acyl donor (fatty acid/palm oil) and kojic acid by esterification using lipase as a biocatalyst in an organic medium. Analysis of the product using GC and FTIR showed the presence of kojic acid ester. The gas chromatography-mass spectrometry (GC-MS) analysis and 1H-NMR and 13C-NMR spectral data confirmed the molecular structure of the kojic acid ester. Among the enzymes tested,lipase from Pseudomonas cepacia gave the highest synthetic specific activity. Oleic acid was found to be the best substrate with which to produce the ester in acetonitrile. The optimum conditions for the synthesis of kojic acid derivatives using Pseudomonas cepacia lipase were time, 24 hr, temperature, 50oC, amount of enzyme, 0.15 g, solvent of log P = -0.33, mole ratio of 4 (kojic acid/oleic acid), with no added water, no control of water activity and oleic acid as substrate.

Kojic acid

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A new cytotoxic carbazole alkaloid fromClausena excavata

Natural Product Research (2007)

Yun Hin Taufiq‐Yap T. H. Peh Gwendoline Cheng Lian Ee M. Rahmani Mohamad Aspollah Sukari

Abstract A new carbazole alkaloid, 3-carbomethoxy-2-hydroxy-7-methoxycarbazole, Clausine-TY (1), together with two known carbazole alkaloid, Clausine-H (2) and Clausine-B (3), were isolated from the ethyl acetate extract of the stem bark of the Malaysian Clausena excavata. The structures of these compounds were elucidated by spectroscopic analyses. The new carbazole alkaloid shows significant cytotoxicity against CEM-SS cell line. Keywords: Clausena excavata RutaceaeStem barkCarbazole alkaloidAnticancer activity Acknowledgement Financial assistance from Universiti Putra Malaysia is greatly acknowledged.

Carbazole

10.1080/14786410701258875

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Citations (32)

Antileukemic Properties of Spermacoce Species

Asian Journal of Chemistry (2013)

Mohamad Aspollah Sukari Rahayu Utami Bee Keat Neoh Gwendoline Cheng Lian Ee S. Jusoh

Antileukemic activity of th extracts and isolated compound from Spermacoce articularis, Spermacoce exilis and Spermacoce latifolia were carried out. All extracts of Spermacoce articularis as well as dichloromethane and ethyl acetate extracts of Spermacoce exilis showed strong activity against HL-60 cancer cell with IC50 value ranging from 0.4 to 7.2 μg/mL, whereas hexane extract of Spermacoce latifolia gave moderate activity with IC50 value of 13 ± 0.19 μg/mL. Ursolic acid as the major isolated constituent of these plants was found to have strong activity with IC50 of 1.3 ± 0.03 μg/mL against the same cancer cell.

Ursolic acid

IC50

Dichloromethane

10.14233/ajchem.2013.14218a

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Citations (2)

Nuclear magnetic resonance characterization of reaction products of interesterification of peracetylated α‐d‐glucopyranose and fatty acid methyl esters

Journal of the American Oil Chemists Society (2000)

Dzulkefly Kuang O. J. Obaje Anuar Kassim Gwendoline Cheng Lian Ee Hamdan Suhaimi

Abstract Mono‐ and diesters of fatty acids of peracetylated α‐d‐glucopyranose were prepared by chemical interesterification. Substituent‐induced chemical shift effects on the carbonyl carbons rather than the ring carbons and proton atoms unambiguosly show the fatty acyl substituents to be at C1 in the monosubstituted, and at C1 and C6 in the disubstituted products. 1 H nuclear magnetic resonance (NMR) integration data before and after interesterification complemented 13 C chemical shift data in verifying the molecular structures. Empirical data from classical 1 H and 13 C NMR experiments thus provide a simple self‐contained method for determining the number and position of fatty acyl substituents, and the anomeric compositions of peracetylated glucose fatty esters.

Interesterified fat

Chemical shift

Proton NMR

10.1007/s11746-000-0007-7

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Effect of Solvents on Phytochemical Concentrations and Antioxidant Activity ofGarcinia benthamianaStem Bark Extracts

Journal of Herbs Spices & Medicinal Plants (2017)

Irene See Gwendoline Cheng Lian Ee Siau Hui Mah Vivien Yi Mian Jong Soek Sin Teh

The effect of solvents of various polarities (hexane, chloroform, ethyl acetate, and methanol) on phytochemical concentrations and antioxidant activities of stem bark of Garcinia benthamiana were examined. A medium polar solvent, ethyl acetate, was the most efficient in extracting the phenolic components from G. benthamiana, followed by methanol. The ethyl acetate extract had high total phenolic concentrations and scavenging activity against 2,2-diphenyl-1-picylhydrazyl (DPPH) free radicals. Both the ethyl acetate and methanol extracts had strong reducing power and moderate ferrous ion chelating ability and inhibition of β-carotene bleaching.

Phytochemical

10.1080/10496475.2016.1272523

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Citations (13)

Secondary metabolites from two garcinia species and their biological activities.

Gwendoline Cheng Lian Ee Lin Cheow Yuen

Detail chemical studies on Garcinia maingayi have yielded one xanthone, 1,3,7-trihydroxy-2-(3-methylbut-2-enyl)xanthone, one benzophenone, isoxanthochymol, one benzoic acid derivative 3,4-dihydroxy-methylbenzoate and two triterpenoids, stigmasterol and sitosterol. Meanwhile, investigations on Garcinia parvifolia have afforded one triterpenoid, α-amyrin and two xanthones, cowanin and rubraxanthone. Their structures were derived based on spectroscopic evidence, mainly 1D and 2D NMR spectroscopy. Acetylation reaction was carried out on rubraxanthone to yield triacetate rubraxanthone. It was found that the pure rubraxanthone was strongly active against the larvae of Aedes aegypti with LC50 value of 15.49 μg/mL and HL-60 cell line with an IC50 value of 7.5 μg/mL.

Xanthone

Garcinia

Stigmasterol

Benzoic acid

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Citations (1)