Chemical Constituents From Annona Muricata (Linn.) and Garcinia Mangostana (Linn.) and Their Biological Activities

Chemical studies were carried out on Annona muricata L. (Annonaceae) and Garcilzia mangostana L. (Guttiferae). The chemical investigations covered acetogenin, triterpenoids and xanthones. These compounds were isolated using common chromatographic techniques and were identified by using spectroscopic technique such as NMR, MS, IR and UV. Biological activities for both plants were also evaluated for their antimicrobial activities against four pathogenic bacteria and four fungi, cytotoxic activity against CEM-SS and HL-60 cell lines and larvicidal activity against Aedes aegypti. Larvicidal activity data have never been reported before.Annona muricata L. (stem bark) have afforded one acetogenin, solamin and two triterpenoids, stigmasterol and sitosterol. Meanwhile studies on Garcinia mangostana L. (bark) have provided a new xanthone, mangosharin (2,8-dihydroxy-6-methoxy-5-(3- methylbut-2-eny1)-xanthone) together with six other xanthones, a-mangostin, Pmangostin, garcinone D, xanthone 1, 1,6-dihydroxy-3,7-dimethoxy-2-(3-methylbut-2- eny1)-xanthone and mangostanol and one triterpenoid, friedelin. Cytotoxic tests were performed using CEM-SS cell line and HL-60 cell line. The crude hexane extract of Annona muricata L. gave a significant activity with an IC50 value of 0.8 pg/ml against CEM-SS cell line while the crude ethyl acetate (EA) extract also gave a significant activity with an IC5v~a lue of 0.5 pg/ml but against HL-60 cell line. The crude hexane extract of Garcinia mangostana L. is also considered to be active against the CEM-SS cell-line with an IC50 value of 17 pg/ml. Other than that, the pure compounds a-mangostin, mangostanol and garcinone D also gave significant activities with ICso values of 5.5,9.6 and 3.2 pg/ml against CEM-SS cell line, respectively. The antimicrobial activity test was also carried out using four pathogenic bacteria, namely, Methicillin Resistant Staphylococcus aures, Pseudomonas aeruginosa, Salmonella typhimurium and Bacillus subtilis. However, most of the crude extracts gave only moderate or weak activity. The pure compound a-mangostin gave weak activity against Salmonella typhimurium and medium inhibition against Bacillus subtilis.The larvicidal tests were performed against the larvae of Aedes a e m i using the WHO (1981) standard procedures with slight modifications. The crude hexane and ethyl acetate extracts of Annona muricata L. showed moderate toxicity towards the larvae by giving LCSO values of less than 100 pg/ml. The crude hexane and ethanol extracts of Garcinia mangostana L. gave weak activities against the larvae with LCso values of more than 150 pglml while the crude ethyl acetate extract showed moderate activity with an LC5() value of 30.1 pg/ml. Larvacidal activity on the pure compound, a-mangostin gave a LCs0 value of 19.4 pglml. No activity was recorded for the antihgal activity test

Garcinia mangostana: a source of potential anti-cancer lead compounds against CEM-SS cell line

Our current interest in searching for natural anti-cancer lead compounds from plants has led us to the discovery that the stem and roots of Garcinia mangostana can be a source of such compounds. The stem furnished 2,8-dihydroxy-6-methoxy-5-(3-methylbut-2-enyl)-xanthone (1), which is a new xanthone. Meanwhile, the root bark of the plant furnished six xanthones, namely -mangostin (2), β-mangostin (3), γ-mangostin (4), garcinone D (5), mangostanol (6), and gartanin (7). The hexane and chloroform extracts of the root bark of G. mangostana as well as the hexane extract of the stem bark were found to be active against the CEM-SS cell line. γ-Mangostin (4) showed good activity with a very low IC50 value of 4.7 μg/ml, while -mangostin (2), mangostanol (6), and garcinone D (5) showed significant activities with IC50 values of 5.5, 9.6, and 3.2 μg/ml, respectively. This is the first report on the cytotoxicity of the extracts of the stem and root bark of G. mangostana and of -mangostin, mangostanol, and garcinone D against the CEM-SS cell line

Xanthones from Calophyllum inophyllum

Repeated separation and purification of fractions from the crude chloroform extract of Calophyllum inophyllum via column chromatography afforded five known xanthone caloxanthones A, B, C, macluraxanthone and pyranojacareubin. Structural elucidations and determination of the isolated compounds were supported by spectral analyses obtained by subjecting the compounds to various spectroscopic techniques. The chloroform extract, when tested against RAW264.7 cells for anti-inflammatory potentials, exhibited the most promising activity with an IC50 value of 14.81±0.04 µg/mL compared to moderate activities shown by the ethyl acetate and n-hexane extracts. Antimicrobial tests showed that the n-hexane and chloroform extracts acted moderately against Staphylococcus epidermidis S273 and Bacillus subtilis B145

Penerokaan awal terhadap motivasi pembelajaran Bahasa Melayu di sebuah universiti awam di Malaysia

Motivasi telah lama dikenal pasti sebagai salah satu faktor utama yang mempengaruhi pembelajaran bahasa (Gardner, 1985). Kajian ini meneliti jenis dan tahap motivasi pembelajaran bahasa Melayu (integrative dan instrumental) dalam kalangan 100 orang mahasiswa di sebuah universiti awam di Malaysia. Kajian rintis ini menggunakan instrument soal selidik yang disesuaikan daripada Gardner Attitude / Motivation Test Batery (AMTB).Data dianalisis dengan menggunakan kekerapan, peratusan, min dan sisihan piawai.Kajian awal ini mendapati bahawa pelajar mempunyai tahap motivasi yang tinggi sama ada motivasi integratif mahupun motivasi instrumental.Dari segi penggunaan dan kembimbangan menggunakan bahasa Melayu pula, kajian mendapati tahap penggunaan Bahasa Melayu adalah memberangsangkan sementara kebimbangan sampel kajian dalm menggunakan Bahasa Melayu pada tahap sederhana. Berdasarkan penemuan ini, beberapa implikasi pembelajaran motivasi relevan dan berguna disyorkan untuk peningkatan dan penambahbaikan motivasi pelaja

Kepuasan kerja guru: Adakah ianya dipengaruhi oleh tingkahlaku kepemimpinan yang ditunjukkan oleh guru besar?

Kajian dilakukan untuk mengenalpasti tingkahlaku kepimpinan guru besar yang dapat meningkatkan kepuasan dan keberksanan kerja guru di sekolah kebangsaan di negeri kedah. Sejumlah 361 orang guru di sekolah kebangsaan di negeri Kedah nterlibat dalam kajian yang menggunakan kaedah tinjauan keratan rentas berdasarkan soal selidik yang diedarkan. Kepimpinan transformasional, kepimpinan transaksional dan kepimpinan laisez-faire merupakan aspek tingkahlaku kepimpinan yang dikaji. Dapatan kajian mendapati kepuasan kerja dan keberkesanan pengajaran dan pembelajaran guru dalam bilik darjah mempunyai hubungan yang signifikan dengan dimensi-dimensi di dalam kepimpinan transformasional dan transaksional. Analisis regresi stepwise mendapati guru besar yang dapat mencetus motivasi dan bertimbang rasa menjadi peramal yang berkesan ka atas peningkatan keberkesanan dan kepuasan kerja seseorang guru. Hasil kajian ini memberi pemahaman mengenai isu-isu dan strategi kepimpinan dalam pendidikan yang perlu di beri penekanan oleh pentadbir sekolah untuk memastian tahap keberkesanan pengajaran dan komitmen kerja guru berada di tahap yang tinggi

A new coumarin from Calophyllum hosei

A new coumarin, hoseimarin (1), together with four other xanthones, trapezifolizanthone (2), osajaxanthone (3), β-mangostin (4) and caloxanthone A (5), were isolated from the stem bark of Calophyllum hosei. The structures of these compounds were established by using spectroscopic analysis which included 1H NMR, 13C NMR, COSY, DEPT, HMQC and HMBC experiments

LC-DAD-ESI-MS analysis of nitric oxide inhibitory fractions of tenggek burung (Melicope ptelefolia Champ. ex Benth)

Solvent–solvent fractionation of the methanolic extract of the popular Malay traditional vegetable “tenggek burung” (Melicope ptelefolia), followed by nitric oxide inhibition assay on RAW 264.7 cells revealed that the most active components reside mainly in hexane and dichloromethane fractions. Online profiling of the nitric oxide (NO) inhibitive fractions of the tenggek burung using liquid chromatography coupled diode array detection and electrospray ion-trap tandem mass spectroscopy (LC–DAD–ESI-MSn), has identified seven constituents. The compounds were identified as kokusaginine (1), compound 2, [kokusagine, (2a) or 5-methoxymaculine (2b)], 2,4,6-trihydroxy-3-prenylacetophenone (3), 2,4,6-trihydroxy-3-geranylacetophenone (4), 2,4,6-trihydroxy-3-geranylgeranylacetophenone (5), 3-[4-O-(3,7-dimethyl-2,6-octadienyl)phenyl]-2-propenoic acid (6) and 2,4,6-trihydroxy-3-farnesylgeranylacetophenone (7). The identity of compounds 1, 4 and 6 were unequivocally confirmed by isolation and spectroscopic evidences, other constituents are tentatively identified, based on their UV, MS, MSn and comparison with literature data. Kokusaginine (1) demonstrated in vitro activity on NO inhibition in murine peritoneal macrophages

Impedance studies on Ca0.5Sr0.5Cu3Ti4O12 ceramic oxide

Ca0.5Sr0.5Cu3Ti4O12 (CSCTO) ceramic oxide was prepared using solid state reaction technique. Impedance measurement was done using High Dielectric Resolution Analyzer (Novocontrol Novotherm) from 30°C to 250°C, in the frequency range of 10-2 to 106 Hz. X-ray diffraction pattern showed a single phase with a cubic structure. In the complex impedance plot, three semi-circles were observed; these represented the grain, grain boundary and electrode effect responses. The semi-circles were fitted using a series network of three parallel RC circuits. The resistance was found to increase with the decreasing temperature. The activation energies, E a, obtained from the Arrhenius plots of CSCTO, were 0.31 eV and 0.73 eV for grain and grain boundary conductivity, respectively. The value of the grain energy was revealed as smaller than the grain boundary energy, due to the semi-conducting grain and the insulating grain boundary characteristic (Sinclair et al., 2002)