MyMedR

Oppositinines A and B: new vasorelaxant beta-carboline alkaloids from Neisosperma oppositifolia

Ahmad K, Thomas NF, Hadi AH, Mukhtar MR, Mohamad K, Nafiah MA, et al.

Chem Pharm Bull (Tokyo), 2010 Aug;58(8):1085-7.

PMID: 20686264

A phytochemical study on the bark of Neisosperma oppositifolia (Apocynaceae) yielded two new beta-carboline indole alkaloids, oppositinines A (1) and B (2), together with five known alkaloids, isoreserpiline, isocarapanaubine, vobasine, 10-methoxydihydrocorynantheol-N-oxide, and ochropposinine oxindole. Structural elucidation of 1 and 2 was performed using 2D NMR methods. Oppositinines A (1) and B (2) showed potent vasorelaxant effects on the rat aorta.

Characterization of a multiwavelength Brillouin-erbium fiber laser based on a linear cavity configuration

Al-Mansoori MH, Saharudin S, Abdul-Rashid H, Mahdi MA, Abdullah MK

Appl Opt, 2005 May 10;44(14):2827-31.

PMID: 15943335

We experimentally demonstrate a simple method for generating a multiwavelength Brillouin comb by utilizing a linear cavity of hybrid Brillouin-erbium fiber lasers (BEFLs). The optimization of Brillouin pump wavelength, power, and erbium gain played a significant role in determining the maximum number of Brillouin Stokes signals generated. Simultaneous and stable multiple-wavelength laser output of 22 lines with 10.88-GHz channel spacing has been obtained with good flatness. Various parameters such as 980-nm pump power, Brillouin pump wavelength, and Brillouin pump power that affect the performance of a multiwavelength BEFL system have been investigated. An analysis of the tuning range of the system is presented.

Fulltext Cognitive impairment and memory dysfunction after a stroke diagnosis: a post-stroke memory assessment

Al-Qazzaz NK, Ali SH, Ahmad SA, Islam S, Mohamad K

Neuropsychiatr Dis Treat, 2014;10:1677-91.

PMID: 25228808 DOI: 10.2147/NDT.S67184

Cognitive impairment and memory dysfunction following stroke diagnosis are common symptoms that significantly affect the survivors' quality of life. Stroke patients have a high potential to develop dementia within the first year of stroke onset. Currently, efforts are being exerted to assess stroke effects on the brain, particularly in the early stages. Numerous neuropsychological assessments are being used to evaluate and differentiate cognitive impairment and dementia following stroke. This article focuses on the role of available neuropsychological assessments in detection of dementia and memory loss after stroke. This review starts with stroke types and risk factors associated with dementia development, followed by a brief description of stroke diagnosis criteria and the effects of stroke on the brain that lead to cognitive impairment and end with memory loss. This review aims to combine available neuropsychological assessments to develop a post-stroke memory assessment (PSMA) scheme based on the most recognized and available studies. The proposed PSMA is expected to assess different types of memory functionalities that are related to different parts of the brain according to stroke location. An optimal therapeutic program that would help stroke patients enjoy additional years with higher quality of life is presented.

Triterpenes and steroids from the leaves of Aglaia exima (Meliaceae)

Awang K, Loong XM, Leong KH, Supratman U, Litaudon M, Mukhtar MR, et al.

Fitoterapia, 2012 Dec;83(8):1391-5.

PMID: 23098876 DOI: 10.1016/j.fitote.2012.10.004

A study on the leaves of Aglaia exima led to the isolation of one new and seven known compounds: six triterpenoids and two steroids. Their structures were elucidated and analyzed mainly by using spectroscopic methods; 1D and 2D NMR, mass spectrometry, UV spectrometry and X-ray. All the triterpenoids and steroids were measured in vitro for their cytotoxic activities against eight cancer cell lines; lung (A549), prostate (DU-145), skin (SK-MEL-5), pancreatic (BxPC-3), liver (Hep G2), colon (HT-29), breast (MCF-7) and (MDA-MB-231). The new cycloartane triterpenoid, 24(E)-cycloart-24-ene-26-ol-3-one 1, showed potent cytotoxic activity against colon (HT-29) cancer cell line (IC(50) 11.5μM).

Fulltext 3-Oxoolean-1-en-28-oic acid-n-hexa-ne-water (4/1/1) from the bark of Walsura pinnata Hassk

Awang K, Yusoff M, Mohamad K, Chong SL, Ng SW

Acta Crystallogr Sect E Struct Rep Online, 2009;65(Pt 5):o1166.

PMID: 21583968 DOI: 10.1107/S1600536809015086

3-Oxoolean-1-en-28-oic acid, isolated from the bark of Walsura pinnata Hassk, crystallized from n-hexane as an n-hexane 0.25-solvent 0.25-hydrate, C(30)H(46)O(3)·0.25C(6)H(14)·0.25H(2)O. There are two independent mol-ecules in the asymmetric unit of the title compound. The three six-membered cyclo-hexane rings in each mol-ecule adopt chair conformations and the carboxyl substituent occupies an axial/equatorial position. The two independent mol-ecules are linked by a pair of O-H(carbox-yl)⋯O hydrogen bonds into a dimer. The n-hexane mol-ecule is disordered about a twofold rotation axis and the water mol-ecule lies on a twofold rotation axis. In addition, the cyclo-hexone carbonyl group of one of the independent mol-ecules is disordered over two sites with occupancies of 0.75 and 0.25.

New alkaloids from Phoebe scortechinii

Awang K, Mukhtar MR, Mustafa MR, Litaudon M, Shaari K, Mohamad K, et al.

Nat Prod Res, 2007 Jul 10;21(8):704-9.

PMID: 17616898

The leaves of the Phoebe scortechinii (Gamb.) Kochummen Comb. Nov. (Lauraceae), afforded one new proaporphine-tryptamine dimer; (-)-phoebescortechiniine (1), along with two known ones; phoebegrandine A and phoebegrandine B. The proaporphine, tetrahydropronuciferine (2), was isolated for the first time as a natural product. The alkaloids were elucidated primarily by means of high field NMR and HRMS.

Erythrocarpines A-E, new cytotoxic limonoids from Chisocheton erythrocarpus

Awang K, Lim CS, Mohamad K, Morita H, Hirasawa Y, Takeya K, et al.

Bioorg Med Chem, 2007 Sep 1;15(17):5997-6002.

PMID: 17576066

Five new cytotoxic limonoids, erythrocarpines A-E (1-5), were isolated from the bark of Chisocheton erythrocarpus Hiern. Chemical structures, stereochemistry, and conformation were fully elucidated and characterized by 2D NMR, MS, and computational methods.

Fulltext Design, synthesis and cytotoxic evaluation of o-carboxamido stilbene analogues

Azmi MN, Din MF, Kee CH, Suhaimi M, Ping AK, Ahmad K, et al.

Int J Mol Sci, 2013;14(12):23369-89.

PMID: 24287912 DOI: 10.3390/ijms141223369

Resveratrol, a natural stilbene found in grapes and wines exhibits a wide range of pharmacological properties. Resveratrol is also known as a good chemopreventive agent for inhibiting carcinogenesis processes that target kinases, cyclooxygenases, ribonucleotide reductase and DNA polymerases. A total of 19 analogues with an amide moiety were synthesized and the cytotoxic effects of the analogues on a series of human cancer cell lines are reported. Three compounds 6d, 6i and 6n showed potent cytotoxicity against prostate cancer DU-145 (IC50=16.68 µM), colon cancer HT-29 (IC50=7.51 µM) and breast cancer MCF-7 (IC50=21.24 µM), respectively, which are comparable with vinblastine. The resveratrol analogues were synthesized using the Heck method.

Fulltext Kingianic acids A-G, Endiandric acid analogues from Endiandra kingiana

Azmi MN, Gény C, Leverrier A, Litaudon M, Dumontet V, Birlirakis N, et al.

Molecules, 2014;19(2):1732-47.

PMID: 24492595 DOI: 10.3390/molecules19021732

A phytochemical investigation of the methanolic extract of the bark of Endiandra kingiana led to the isolation of seven new tetracyclic endiandric acid analogues, kingianic acids A-G (1-7), together with endiandric acid M (8), tsangibeilin B (9) and endiandric acid (10). Their structures were determined by 1D- and 2D-NMR analysis in combination with HRMS experiments. The structure of compounds 9 and 10 were confirmed by single-crystal X-ray diffraction analysis. These compounds were screened for Bcl-xL and Mcl-1 binding affinities and cytotoxic activity on various cancer cell lines. Compound 5 showed moderate cytotoxic activity against human colorectal adeno-carcinoma (HT-29) and lung adenocarcinoma epithelial (A549) cell lines, with IC50 values in the range 15-17 µM, and compounds 3, 6 and 9 exhibited weak binding affinity for the anti-apoptotic protein Mcl-1.

Fulltext Prevalence and Factors Influencing Visual Memory Dysfunction among Epilepsy Patients-A Single-Center Study

Beh HC, Tan HJ, Hod R, Khoo CS, Mohamad K

Neurol India, 2020 7 10;68(3):581-585.

PMID: 32643667 DOI: 10.4103/0028-3886.289011

Background: Epilepsy is associated with cognitive impairment due to the disease itself or side-effects of antiepileptic drugs.

Objective: We aimed to study the prevalence of visual memory dysfunction among epilepsy patients and identify the predictors that could contribute to the impairment.

Materials and Methods: This was a cross-sectional study. We analyzed 250 patients with epilepsy from neurology clinic at our tertiary center. Assessment of visual memory was done using Wechsler Memory Scale-IV (WMS-IV) with scores from subsets of visual reproduction I, II and designs I, II contributing to visual memory index (VMI) score. The correlation between continuous variables was analyzed using Pearson correlation; whereas the VMI scores of different factors were analyzed via a 1-way ANOVA test. The statistical significance was set at P < 0.05.

Results: The prevalence of visual memory dysfunction in our epilepsy population was 37.2%. Analysis of individual predictors showed that older patients, lower educational level, combined generalized and focal types of epilepsy, longer duration of epilepsy, greater number of antiepileptic drugs (AEDs) used, and abnormal neuroimaging contributed to poor visual memory. Multiple logistic regression analysis showed that educational level, types of epilepsy, and the number of AEDs used were significant predictors for visual memory impairment.

Conclusion: Visual memory dysfunction in patients with epilepsy was due to manifold confounding factors. Our findings enabled us to identify patients with visual memory dysfunction and modifiable factors that contribute to it. WMS-IV is a suitable assessment tool to determine visual memory function, which can help clinicians to optimize the patients' treatment.

Bioactivity-guided fractionation of the lipoxygenase and cyclooxygenase inhibiting constituents from Chisocheton polyandrus Merr

Chan KY, Mohamad K, Ooi AJ, Imiyabir Z, Chung LY

Fitoterapia, 2012 Jul;83(5):961-7.

PMID: 22565147 DOI: 10.1016/j.fitote.2012.04.018

Lipoxygenase (LOX)-inhibiting compounds from the leaves of Chisocheton polyandrus Merr. were isolated in this study using a bioactivity-guided fractionation technique. Two dammarane triterpenoids, dammara-20,24-dien-3-one (1) (IC(50)=0.69±0.07 μM) and 24-hydroxydammara-20,25-dien-3-one (2) (IC(50)=1.11±0.38 μM), were isolated and identified based on the soybean LOX assay. Dammara-20,24-dien-3-one (1) exhibited dual inhibition of both human 5-LOX (IC(50)=24.27±2.92 μM) and cyclooxygenase-2 (COX-2) (IC(50)=3.17±0.90 μM), whereas 24-hydroxydammara-20,25-dien-3-one (2) did not exhibit any significant inhibitory effects. This report is the first to detail the inhibition of LOX and COX by both C. polyandrus and its isolated compounds.

An ethnobotanical study of medicinal plants used by tribal and native people of Madhupur forest area, Bangladesh

Islam MK, Saha S, Mahmud I, Mohamad K, Awang K, Jamal Uddin S, et al.

J Ethnopharmacol, 2014 Feb 3;151(2):921-30.

PMID: 24342778 DOI: 10.1016/j.jep.2013.11.056

Madhupur forest area, Tangail is one of early human settlements in Bangladesh. Having abode in the vicinity of the forest, a strong ethnobotanical practice has prevailed in this area since ancient time. Due to the rapid deforestation during the last few decades, many plants have already disappeared or are facing extinction. Thus we attempted to document the medicinal plant use of Madhupur forest area with a view to preserve the ethnobotanical knowledge and in order to protect the biodiversity of this area.

Nutritional quality of germinated cowpea flour (Vigna unguiculata) and its application in home prepared powdered weaning foods

Jirapa P, Normah H, Zamaliah MM, Asmah R, Mohamad K

Plant Foods Hum Nutr, 2001;56(3):203-16.

PMID: 11442221

Amino acid profiles, protein digestibility, corrected amino acid scores (PDCAAS), chemical scores, essential amino acid indexes, and calculated biological values of controlcowpea flour (CCF), germinated cowpea flour (GCF) prepared from cowpeas germinated at 25 degrees C for either 24 h or 48 h and weaning foods prepared from cowpea flours were determined. Locally available rice, cowpea flour, banana-pumpkin slurry, and skim milk powder and sucrose in the ratio 35:35:15:15:5 were used to formulate weaning food containing not less than 15% protein. The ingredients were cooked into a slurry and oven-dried to produce flakes. The nutritional and sensory qualities of the weaning products were evaluated. Germination had little effect on the amino acid profile of cowpeas. In vitro protein quality and starch digestibility were improved in germinated cowpea flour. The PDCAAS of 24 h germinated cowpea flour (GCF) weaning food was higher (55.49%) than CCF-weaning food (46.74%). Vitamin A activity in 24 h GCF weaning food was higher than in CCF-weaning food. In vitro starch digestibilities of 24 h GCF and 48 h GCF-weaning foods were higher than that of CCF weaning food. The 24 h GCF-weaning food which had a higher overall acceptability score by sensory panelist than 48 h GCF and CCF-weaning food is recommended for household consumption.

Fulltext Chemical constituents of aglaia lanuginose

Kamarulzaman, F. A., Mohamad, K., Awang, K., Lee, H. B.

Pertanika Journal of Science & Technology, 2014;22(1):163-174.

MyJurnal

Our continuing research on the Aglaia genus (family Meliaceace) has led us to this first study on the chemical constituents of Aglaia lanuginose (bark). The dichloromethane extract from the bark of Aglaia lanuginose showed cytotoxicity against HL-60 leukaemia cell line (45% inhibition) at 20 µg/ml and was prioritised for further investigation. Repeated chromatography of the dichloromethane extract yielded the known dammarane triterpenes which were identified as cabralealactone (1), methyl eichlerianate (2), cabraleone (3), ocotillone (4), eichleriatone (5), eichlerianic acid (6) and shoreic acid (7) together with the known sterols, sitosterol (9) and stigmasterol (10). Another isolated compound was the aromatic 4-hydroxycinnamyl-acetate (8), which has not been reported to be present in a plant from the Meliaceae family. The structures of all the compounds were elucidated on the basis of spectroscopic methods (IR, MS and NMR). Cytotoxicity testing of 1-10 showed activity only for mixtures of (3, 4), and (5, 6).

Fulltext Effects of moringa leaves (Moringa oleifera) extraction on quality changes and melanosis of giant freshwater prawn (Macrobrachium rosenbergii) during chilled storage

Karim NU, Siddiq USAA, Razak MRM, Zainol MKM, Abdullah MI

Ital J Food Saf, 2018 Sep 26;7(3):6846.

PMID: 30538958 DOI: 10.4081/ijfs.2018.6846

An aqueous extraction of moringa (Moringa oleifera) leaves were prepared as the edible coats for keeping the quality of the giant freshwater prawn (Macrobrachium rosenbergii). In addition, the antioxidant properties and activity; total phenolic content (TPC), total flavonoid contents (TFC), free radical scavenging activity (DPPH), and ferric reducing antioxidant power (FRAP) of moringa leaves were also determined. The phenolic compounds and antioxidant properties in the moringa leaves are low; 16.14 mgGAEg-1 for TPC; 5.57 mgQEg-1 for TFC; 1.36 mgTEg-1 for DPPH; and 3.05 mgTEg-1 for FRAP. The experiment was further conducted by coating the M. rosenbergii with moringa leaves extraction before chilled storage at 4°C for 15 days. Moringa leaves extraction were effectively reduced the microflora count in M. rosenbergii (P<0.05). Total volatile basis nitrogen (TVB-N) value showed a significant (P<0.05) lower amount in treated samples compared to the controls. Melanosis were obvious in controls compared to the treated samples. After 15 days of chilled storage, the sensory properties; taste, texture and odour of treated samples were acceptable by the panelists. Biopreservation of moringa leaves extraction significantly benefits in keeping the quality of M. rosenbergii.

Fulltext Cytotoxic and antioxidant compounds from the stem bark of Goniothalamus tapisoides Mat Salleh

Kim RP, Bihud V, Bin Mohamad K, Leong KH, Bin Mohamad J, Bin Ahmad F, et al.

Molecules, 2012 Dec 21;18(1):128-39.

PMID: 23344192 DOI: 10.3390/molecules18010128

Eleven compounds:goniomicin A (1), goniomicin B (2), goniomicin C (3), goniomicin D (4), tapisoidin (5), goniothalamin (6), 9-deoxygoniopypyrone (7), pterodondiol (8), liriodenine (9), benzamide (10) and cinnamic acid (11), were isolated from the stem bark of Goniothalamus tapisoides. All compounds were identified by spectroscopic analysis and, for known compounds, by comparison with published data. Goniothalamin (6) exhibited mild cytotoxic activity towards a colon cancer cell line (HT-29), with an IC(50)value of 64.17 ± 5.60 µM. Goniomicin B (2) give the highest antioxidant activity in the DPPH assay among all compounds tested, with an IC(50) of 0.207 µM.

Fulltext Induction of apoptosis in melanoma A375 cells by a chloroform fraction of Centratherum anthelminticum (L.) seeds involves NF-kappaB, p53 and Bcl-2-controlled mitochondrial signaling pathways

Looi CY, Moharram B, Paydar M, Wong YL, Leong KH, Mohamad K, et al.

BMC Complement Altern Med, 2013;13:166.

PMID: 23837445 DOI: 10.1186/1472-6882-13-166

Centratherum anthelminticum (L.) Kuntze (scientific synonyms: Vernonia anthelmintica; black cumin) is one of the ingredients of an Ayurvedic preparation, called "Kayakalp", commonly applied to treat skin disorders in India and Southeast Asia. Despite its well known anti-inflammatory property on skin diseases, the anti-cancer effect of C. anthelminticum seeds on skin cancer is less documented. The present study aims to investigate the anti-cancer effect of Centratherum anthelminticum (L.) seeds chloroform fraction (CACF) on human melanoma cells and to elucidate the molecular mechanism involved.

Fulltext Induction of apoptosis in human breast cancer cells via caspase pathway by vernodalin isolated from Centratherum anthelminticum (L.) seeds

Looi CY, Arya A, Cheah FK, Muharram B, Leong KH, Mohamad K, et al.

PLoS One, 2013;8(2):e56643.

PMID: 23437193 DOI: 10.1371/journal.pone.0056643

Centratherum anthelminticum (L.) seeds (CA) is a well known medicinal herb in Indian sub-continent. We recently reported anti-oxidant property of chloroform fraction of Centratherum anthelminticum (L.) seeds (CACF) by inhibiting tumor necrosis factor-α (TNF-α)-induced growth of human breast cancer cells. However, the active compounds in CACF have not been investigated previously.

Fulltext Pinnatane A from the bark of Walsura pinnata Hassk

Mohamad K, Yusoff M, Awang K, Ahmad K, Ng SW

Acta Crystallogr Sect E Struct Rep Online, 2009;65(Pt 6):o1317.

PMID: 21583174 DOI: 10.1107/S1600536809015955

In the mol-ecule of pinnatane A, C(30)H(48)O(3), isolated from the bark of Walsura pinnata Hassk, the four cyclo-hexane rings adopt chair conformations; the carboxyl and hydr-oxy substituents occupy axial positions. The cyclo-hexene ring is envelope-shaped. Adjacent mol-ecules are linked by O-H⋯O hydrogen bonds into a chain running along the c axis.

Cytotoxic 3,4-secoapotirucallanes from Aaglaia argentea bark

Mohamad K, Martin MT, Najdar H, Gaspard C, Sévenet T, Awang K, et al.

J Nat Prod, 1999 Jun;62(6):868-72.

PMID: 10395505

Nine 3,4-secoapotirucallanes, argentinic acids A-I, were isolated from the bark of Aglaia argentea and transformed to their methyl esters 1-9. The structures were determined by spectral and chemical means. Compounds 1-8 showed moderate cytotoxic activity against KB cells (IC50 1.0-3.5 microg/mL).

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