Publications by authors named "Mohammad Razak Hamdan"

6 Publications

  • Page 1 of 1

In Vitro Cytotoxic Activity of Clinacanthus nutans Leaf Extracts Against HeLa Cells

Asian Pac J Cancer Prev 2019 Feb 26;20(2):601-609. Epub 2019 Feb 26.

Advanced Medical and Dental Institute, Universiti Sains Malaysia, Bertam, 13200 Kepala Batas, Penang, Malaysia. Email:

Objective: This study was conducted to investigate the antiproliferative activity of extracts of Clinacanthus nutans leaves against human cervical cancer (HeLa) cells. Methods: C. nutans leaves were subjected to extraction using 80% methanol or water. The methanol extract was further extracted to obtain hexane, dichloromethane (DCM), and aqueous fractions. The antiproliferative activity of the extracts against HeLa cells was determined. The most cytotoxic extract was furthered analyzed by apoptosis and cell cycle assays, and the phytochemical constituents were screened by gas chromatography-mass spectrometry (GC-MS). Results: All of the extracts were antiproliferative against HeLa cells, and the DCM fraction had the lowest IC50 value of 70 μg/mL at 48 h. Microscopic studies showed that HeLa cells exposed to the DCM fraction exhibited marked morphological features of apoptosis. The flow cytometry study also confirmed that the DCM fraction induced apoptosis in HeLa cells, with cell cycle arrest at the S phase. GC-MS analysis revealed the presence of at least 28 compounds in the DCM fraction, most of which were fatty acids. Conclusion: The DCM fraction obtained using the extraction method described herein had a lower IC50 value than those reported in previous studies that characterized the anticancer activity of C. nutans against HeLa cells.
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http://dx.doi.org/10.31557/APJCP.2019.20.2.601DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6897000PMC
February 2019

Assessment of three plastid DNA barcode markers for identification of (Acanthaceae).

3 Biotech 2018 Jan 11;8(1):62. Epub 2018 Jan 11.

2School of Biological Sciences, Universiti Sains Malaysia, 11800 Gelugor, Penang Malaysia.

This study was conducted to determine the feasibility of using three plastid DNA regions (, -, and ) as DNA barcodes to identify the medicinal plant . In this study, was collected at several different locations. Total genomic DNA was extracted, amplified by polymerase chain reaction (PCR), and sequenced using , -, and , primers. DNA sequences generated from PCR were submitted to the National Center for Biotechnology Information's (NCBI) GenBank. Identification of was carried out using NCBI's Basic Local Alignment Search Tool (BLAST). The and - regions successfully identified with sequencing rates of 100% through BLAST identification. Molecular Evolutionary Genetics Analysis (MEGA) 6.0 was used to analyze interspecific and intraspecific divergence of plastid DNA sequences. and exhibited the lowest average interspecific distance (0.0487 and 0.0963, respectively), whereas - exhibited the highest average interspecific distance (0.2029). The R package Spider revealed that - correctly identified Barcode of Life Data System (BOLD) 96%, best close match 79%, and near neighbor 100% of the species, compared to (BOLD 72%; best close match 64%; near neighbor 78%) and (BOLD 77%; best close match 62%; near neighbor 88%). These results indicate that - is very effective at identifying , as it performed well in discriminating species in Acanthaceae.
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http://dx.doi.org/10.1007/s13205-018-1092-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5762596PMC
January 2018

Evaluation of genetic diversity of (Acanthaceaea) using RAPD, ISSR and RAMP markers.

Physiol Mol Biol Plants 2016 Oct 31;22(4):523-534. Epub 2016 Oct 31.

Central Drug Research Institute, Universiti Sains Malaysia, 11800 Gelugor, Penang Malaysia.

Three polymerase chain reaction (PCR) techniques were compared to analyse the genetic diversity of eight populations in the northern region of Peninsular Malaysia. The PCR techniques were random amplified polymorphic deoxyribonucleic acids (RAPD), inter-simple sequence repeats (ISSR) and random amplified microsatellite polymorphisms (RAMP). Leaf genomic DNA was PCR amplified using 17 RAPD, 8 ISSR and 136 RAMP primers . However, only 10 RAPD primers, 5 ISSR primers and 37 RAMP primers produced reproducible bands. The results were evaluated for polymorphic information content (PIC), marker index (MI) and resolving power (RP). The RAMP marker was the most useful marker compared to RAPD and ISSR markers because it showed the highest average value of PIC (0.25), MI (11.36) and RP (2.86). The genetic diversity showed a high percentage of polymorphism at the species level compared to the population level. Furthermore, analysis of molecular variance revealed that the genetic diversity was higher within populations, as compared to among populations of . From the results, the RAMP technique was recommended for the analysis of genetic diversity of
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http://dx.doi.org/10.1007/s12298-016-0391-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5120048PMC
October 2016

Flavonoids-Rich Orthosiphon stamineus Extract as New Candidate for Angiotensin I-Converting Enzyme Inhibition: A Molecular Docking Study.

Molecules 2016 Nov 9;21(11). Epub 2016 Nov 9.

Department of Pharmaceutical Chemistry, School of Pharmaceutical Sciences, Universiti Sains Malaysia, Minden, Penang 11800, Malaysia.

This study aims to evaluate the in vitro angiotensin-converting enzyme (ACE) inhibition activity of different extracts of (OS) leaves and their main flavonoids, namely rosmarinic acid (RA), sinensetin (SIN), eupatorin (EUP) and 3'-hydroxy-5,6,7,4'-tetramethoxyflavone (TMF). Furthermore, to identify possible mechanisms of action based on structure-activity relationships and molecular docking. The in vitro ACE inhibition activity relied on determining hippuric acid (HA) formation from ACE-specific substrate (hippuryl-histidyl-leucine (HHL)) by the action of ACE enzyme. A High Performance Liquid Chromatography method combined with UV detection was developed and validated for measurement the concentration of produced HA. The chelation ability of OS extract and its reference compounds was evaluated by tetramethylmurexide reagent. Furthermore, molecular docking study was performed by : BioSolveIT's LeadIT program. OS ethanolic extract (OS-E) exhibited highest inhibition and lowest IC value (45.77 ± 1.17 µg/mL) against ACE compared to the other extracts. Among the tested reference compounds, EUP with IC 15.35 ± 4.49 µg/mL had highest inhibition against ACE and binding ability with Zn (II) (56.03% ± 1.26%) compared to RA, TMF and SIN. Molecular docking studies also confirmed that flavonoids inhibit ACE via interaction with the zinc ion and this interaction is stabilized by other interactions with amino acids in the active site. In this study, we have demonstrated that changes in flavonoids active core affect their capacity to inhibit ACE. Moreover, we showed that ACE inhibition activity of flavonoids compounds is directly related to their ability to bind with zinc ion in the active site of ACE enzyme. It was also revealed that OS extract contained high amount of flavonoids other than RA, TMF, SIN and EUP. As such, application of OS extract is useful as inhibitors of ACE.
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http://dx.doi.org/10.3390/molecules21111500DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6274529PMC
November 2016

Selected metabolites profiling of Orthosiphon stamineus Benth leaves extracts combined with chemometrics analysis and correlation with biological activities.

BMC Complement Altern Med 2015 Oct 7;15:350. Epub 2015 Oct 7.

Department of Pharmaceutical Chemistry, School of Pharmaceutical Sciences, Universiti Sains Malaysia, Minden, 11800, Pulau Pinang, Malaysia.

Background: Studies on selected metabolites profiling of Orthosiphon stamineus extracts using chromatographic and spectroscopic techniques combined with chemometric tools have not been fully elucidated. Thus present study was performed to profile selected metabolites in O. stamineus leaves extracts using HPLC and FTIR combined with chemometric tools and correlated with biological activities.

Methods: Five different extracts were prepared using three methods; maceration, soxhlet and reflux. The extracts were analyzed using UV-Vis, HPLC and FTIR techniques. Analysis of selected primary and secondary metabolites was also evaluated. The antioxidant and cytotoxic activities of the extracts were evaluated. Chemometric tools were employed to classify the extracts based on HPLC analysis and FTIR fingerprints.

Results: The ethanolic extract using maceration characterized high content of phenolics and flavonoids, (rosmarinic acid and eupatorin) with high antioxidant activity. Ethanolic (50%) and methanolic extracts using soxhlet showed high proteins and glycosaponins. Water extracts using reflux and maceration showed high polysaccharides. Methanolic extract (50%) using soxhlet and methanolic extract using maceration showed strong cytotoxic effect against MCF7 and HCT116 cell lines, respectively. Antioxidant and cytotoxic activities showed significant correlation with selected primary and secondary metabolites. HPLC fingerprints combined with chemometrics showed the extracts have been clustered based on selected major peaks profile. FTIR fingerprints combined with chemometrics showed that the extracts have been clustered based on protein and polysaccharide contents.

Conclusion: Ten different extracts of O. stamineus have showed significant differences in the content of selected primary and secondary metabolites as well as the biological activities. Chemometric tools were able to classify and discriminate the distinctive features of extracts thus can be correlated with the biological activities.
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http://dx.doi.org/10.1186/s12906-015-0884-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4597610PMC
October 2015

A simple HPLC-DAD method for the detection and quantification of psychotropic mitragynine in Mitragyna speciosa (ketum) and its products for the application in forensic investigation.

Forensic Sci Int 2013 Mar 4;226(1-3):183-7. Epub 2013 Feb 4.

Centre for Drug Research, Universiti Sains Malaysia, 11800 Penang, Malaysia.

Mitragyna speciosa, a native plant of Thailand and Malaysia known as 'ketum', is a plant of considerable interest. It exhibits strong antinociceptive effect and yet, acts like a psychostimulant. Due to the affordability and its ease of availability, the abuse of this plant as a substitute for other banned narcotics has become a major concern in many societies. In countries such as Thailand, Myanmar, Australia and Malaysia, the use of ketum is illegal. However, for a person to be charged for possessing or selling ketum, a reliable analytical method is needed in order to detect and identify the plant and its products. Mitragynine is the major alkaloid of ketum. This compound manifests its antinociceptive effects by acting on the opioid receptors. Since M. speciosa contain large quantity of mitragynine and it is exclusive to the species, the present analytical method is developed and validated for the purpose of screening ketum products based on this unique compound as the analytical marker. The method uses a HPLC-DAD system with Inertsil C8 (4.6 mm × 150 mm, 5 μm) as the column and a mixture of acetonitrile and formic acid, 50:50 (v/v), as the mobile phase. This method not only detects mitragynine, it can also be used to quantify the amount of mitragynine in the sample. The limit of detection is 0.25 μg/ml, while the limit of quantification is 0.50 μg/ml. The method is quick, simple and reliable with an accuracy of 97.27-101.74% and coefficient of variations of between 0.91 and 3.96%. The method has been tested and found suitable for the identification and quantification of mitragynine in dried plants, a variety of ketum extracts, as well as ketum drink obtained from the market.
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http://dx.doi.org/10.1016/j.forsciint.2013.01.014DOI Listing
March 2013