Browsing by Author "Chan, KW"
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Publication Dillenia suffraticosa exhibited antioxidant and cytotoxic activity through induction of apoptosis and G(2)/M cell cycle arrest(Elsevier Ireland Ltd, 2013) ;Armania, N ;Yazan, LS ;Musa, SN ;Ismail, IS ;Foo, JB ;Chan, KW ;Noreen, H ;Hisyam, AH ;Zulfahmi, SIsmail, MEthnopharmacological relevance: Dillenia suffruticosa (Family: Dilleniaceae) locally known as Simpoh air has been reported to be used traditionally to treat cancerous growth. Therefore, the present study was attempted to investigate the antioxidant and cytotoxic properties of different parts (root, flower, fruit and leaf) of D. suffruticosa extracts. Methods and materials: In this study, direct solvent extraction (aqueous and methanol) from different parts of D. suffruticosa (root, flower, fruit and leaf) were carried out. Antioxidant activities of D. suffruticosa extract were determined by using DPPH, ABTS FRAP and beta-carotene bleaching assays. Cytotoxicity and cell cycle arrest of the active extract were determined using MTT assay and flow cytometer, respectively. Sequential solvent extraction (hexane, DCM, EtOAc, and MeOH) were also carried out in root of D. suffruticosa to further evaluate the antioxidant and cytotoxic activity of the different solvent extracts. Results: Methanol (MeOH) root extract showed the highest TPC, antioxidant and cytotoxic activities (especially towards HeLa) compared to others (P < 0.05). Based on the results, sequential solvent extraction (hexane, DCM, EtOAc and MeOH) was carried out in the roots of D. suffruticosa. MeOH extract exhibited the highest antioxidant activities among others and significantly correlated (P < 0.05) with TPC, suggesting the important contribution of phenolic compounds to its antioxidant activity. On the other hand, the DCM and EtOAc exhibited higher cytotoxic activity to selected cancer cells (HeLa, MCF-7, MDA-MB-231, A549 and HT29) compared to others. In short, there is no established correlation between antioxidant and cytotoxic activities of D. suffruticosa extracts indicating that an agent with high antioxidant activities will not necessarily possesses good cytotoxic activities in return. Qualitative phytochemical screening of D. suffruticosa extracts suggested the presence of saponins, triterpenes, sterols, and polyphenolic compounds which are believed to contribute to the cytotoxic activities. Conclusion: It is suggested that the cytotoxicity of the active extracts in HeLa was due to the induction of apoptosis and cell cycle arrest at G(2)/M. (C) 2013 Elsevier Ireland Ltd. All rights reserved. - Some of the metrics are blocked by yourconsent settings
Publication Microwave synthesis, crystal structure, antioxidant, and antimicrobial study of new 6-heptyl-5,6-dihydrobenzo[4,5]imidazo[1,2-c]quinazoline compound(Springeropen, 2018) ;Hasan, HA ;Abdulmalek, E ;Rahman, MBA ;Shaari, KB ;Yamin, BMChan, KWBackgroundAlthough the development of antibiotic and antioxidant manufacturing, the problem of bacterial resistance and food and/or cosmetics oxidation still needs more efforts to design new derivatives which can help to minimize these troubles. Benzimidazo[1,2-c]quinazolines are nitrogen-rich heterocyclic compounds that possess many pharmaceutical properties such as antimicrobial, anticonvulsant, immunoenhancer, and anticancer.ResultsA comparative study between two methods, (microwave-assisted and conventional heating approaches), was performed to synthesise a new quinazoline derivative from 2-(2-aminophenyl)-1H-benzimidazole and octanal to produce 6-heptyl-5,6-dihydrobenzo[4,5]imidazo[1,2-c]quinazoline (OCT). The compound was characterised using FTIR, H-1 and C-13 NMR, DIMS, as well as X-ray crystallography. The most significant peak in the C-13 NMR spectrum is C-7 at 65.5ppm which confirms the cyclisation process. Crystal structure analysis revealed that the molecule grows in the monoclinic crystal system P2(1)/n space group and stabilised by an intermolecular hydrogen bond between the N1-H1A...N3 atoms. The crystal packing analysis showed that the molecule adopts zig-zag one dimensional chains. Fluorescence study of OCT revealed that it produces blue light when expose to UV-light and its' quantum yield equal to 26%. Antioxidant activity, which included DPPH and ABTS(+) assays was also performed and statistical analysis was achieved via a paired T-test using Minitab 16 software with P<0.05. Also, the antimicrobial assay against two Gram-positive, two Gram-negative, and one fungus was screened for these derivatives.ConclusionsUsing microwave to synthesise OCT have drastically reduced reaction time, and increased yield. OCT show good antioxidant activity in one of the tests and moderate antimicrobial activity. - Some of the metrics are blocked by yourconsent settings
Publication Synthesis of novel 6-substituted-5,6-Dihydrobenzo[4,5] Imidazo[1,2-c] quinazoline compounds and evaluation of their properties(Elsevier Science BV, 2019-10-05) ;Hasan, HA ;Abdulmalek, E ;Saleh, TA ;Rahman, MBA ;Shaari, KB ;Yamin, BMChan, KWNew 6-substituted-5,6-dihydrobenzo[4,5] imidazo[1,2-c] quinazoline compounds were synthesized using two different protocols: microwave-enhanced and classical heating methods. A comparison study that was set up to compare both the methods and the results showed that the microwave-assisted method produced a better percentage yield (up to 98%) in a very short reaction time (only a few minutes). All compounds were characterized by spectroscopic and elemental analysis. Only one compound was analyzed by single crystal X-ray diffraction despite the difficulties of getting good crystal even after several attempts. The X-ray crystallography results were chemically acceptable and confirmed the structure of benzimidazoquinazoline 5. Incidentally, the studied derivatives were found to emit a very nice blue light when exposed to UV-light. Therefore, a photoluminescence study was performed as a part of the characterization processes. Biological application as an antimicrobial and an antioxidant for the target analogues was performed. Some derivatives exhibited high antibacterial activity against studied Gram-positive strains, although they were not active against Gram-negative strains. Moreover, some of them showed excellent antioxidant activities against both of the studied antioxidant DPPH center dot and ABTS(center dot)(+) radicals. (C) 2019 Elsevier B.V. All rights reserved.