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Title:	Aktiviti antimalaria Gleichenia truncata melibatkan perencatan glikogen sintase kinase 3B (GSK3B)
Authors:	Suhaini Sudi (P62700)
Supervisor:	Hasidah Mohd Sidek, Prof. Madya Dr.
Keywords:	Glikogen sintase kinase-3 (GSK3) Antimalaria Gleichenia truncata Glycogen synthase kinase-3.
Issue Date:	22-Feb-2015
Description:	Disfungsi glikogen sintase kinase-3 (GSK3) iaitu serin/treonin kinase yang dikenalpasti terlibat dalam pelbagai proses sel, dikaitkan dengan beberapa penyakit manusia termasuk penyakit berkait-infeksi parasit. Kajian terkini menunjukkan pertumbuhan parasit plasmodium boleh direncat melalui perencatan GSK3, justeru GSK3 berpotensi sebagai sasaran terapi antimalaria. Kajian ini bertujuan untuk menilai aktiviti antimalaria ekstrak kasar, fraksi dan sebatian daripada tumbuhan ubatan Gleichenia truncata yang digunakan secara tradisional untuk mengurangkan demam; dan mengkaji penglibatan GSK3 dalam mekanisme tindakan. Hasil penyaringan antiplasmodium ekstrak kasar metanol dan etanol (EKM dan EKE) serta fraksi kloroform dan heksana (FK dan FH) menggunakan asai plasmodium laktat dehidrogenase (pLDH) menunjukkan bahawa tiga daripada empat sampel yang diuji, EKM, EKE dan FK merencat pertumbuhan kultur parasit P. falciparum strain 3D7 dan K1 dengan aktif (0.20<IC50<12.05 µg/mL). Indeks pemilihan (SI) EKM, EKE dan FK melebihi 10 diperoleh daripada nisbah IC50 (MTT):IC50 (pLDH) menunjukkan sampel diuji dapat merencat pertumbuhan kedua-dua strain parasit secara selektif dengan memberikan kesan minimum terhadap sel hepar Chang. Ujian penindasan empat hari in vivo menunjukkan perlakuan secara intraperitoneum sehingga 250 mg/kg berat tubuh (BT) EKM, EKE atau FK G. truncata menyebabkan penindasan yang baik (kemopenindasan >70%) terhadap perkembangan P. berghei NK65 dalam eritrosit. Kemandirian mencit terinfeksi dengan perlakuan semua sampel G. truncata diuji didapati lebih lama berbanding haiwan terinfeksi tanpa perlakuan. Di samping itu, mencit normal (tanpa infeksi) yang diberikan sehingga 250 mg/kg BT EKM, EKE, FK G. truncata selama empat hari berturut-turut hidup sepanjang 30 hari tempoh pemantauan. Analisis Western GSK3 terfosfat dan tak terfosfat hepar dan parasit semasa infeksi P. berghei menunjukkan perlakuan G. truncata meningkatkan pemfosfatan Ser9 GSKβ berbanding sampel daripada mencit tanpa perlakuan. Hasil sama diperoleh pada hepar mencit tanpa infeksi (normal) yang diberikan perlakuan EKM, EKE dan FK. Analisis fitokimia EKM menunjukkan kehadiran metil-4-hidroksisinamat (p-asid koumarik metil ester) yang mempamer aktiviti antiplasmodium yang aktif terhadap 3D7 (IC50=8.41±1.25 µM; SI>100) dan sederhana aktif terhadap K1 (IC50=29.14±1.25 µM; SI>100). Hasil kajian ini menunjukkan aktiviti antimalaria ekstrak kasar dan fraksi G. truncata melibatkan perencatan GSK3β hepar dan parasit semasa infeksi plasmodium. Hasil kajian juga menunjukkan potensi metil-4-hidroksisinamat sebagai sebatian antiplasmodium justeru memberikan bukti saintifik penggunaan etnoperubatan tumbuhan ini bagi merawat penyakit berkait-inflamasi.,Dysfunction of glycogen synthase kinase-3 (GSK3), a serine/threonine kinase known to be involved in a diverse range of cellular processes is associated with several human ailments including parasite infection-related diseases. Recent studies indicate that plasmodial parasite growth may be inhibited via inhibition of GSK3 thus making GSK3 a plausible target for development of antimalarial therapeutics. The present study aims to evaluate the antimalarial activities of crude extracts, fractions and compound(s) derived from a medicinal fern, Gleichenia truncata traditionally used to alleviate fevers; and to investigate the involvement of GSK3 in the mechanism of action. In vitro antiplasmodial screening of crude methanolic and ethanolic extracts (EKM and EKE) as well as chloroform and hexane fractions (FK and FH) using plasmodial lactate dehydrogenase (pLDH assay) showed that three out of the four samples examined, EKM, EKE and FK displayed active inhibition on growth of 3D7 and K1 P. falciparum parasite strains in culture (0.20<IC50<12.05 µg/mL). Selectivity indices (SI) for EKM, EKE and FK determined from the IC50 (MTT):IC50 (pLDH) ratio showed excellent values exceeding the SI cut-off value of 10 thus indicating high selectivity of the test samples to inhibit growth of both parasite strains with minimal effects on mammalian Chang liver cells. In vivo 4-day suppressive test showed that intraperitoneal (ip) administration of up to 250 mg/kg body weight (bw) G. truncata EKM, EKE or FK into P. berghei-infected mice caused good suppression (chemosuppression >70%) of P. berghei development in erythrocytes. Survivability of infected mice treated with all G. truncata preparations tested were prolonged compared to non-treated infected animals. In addition, normal (non-infected) mice injected for four consecutive days with up to 250 mg/kg bw of G. truncata EKM, EKE or FK survived throughout the 30-day observation period. Western analysis of liver and parasite phosphorylated and non-phosphorylated GSK3 during P. berghei infection revealed that treatment with G. truncata preparations resulted in increased Ser9 phosphorylation of GSK3β compared to samples from non-treated group of mice. Similar results were obtained in liver of non-infected (normal) mice in response to EKM, EKE and FK administrations. Phytochemical analysis of EKM showed the presence of methyl-4-hydroxycinnamate (p-coumaric acid methyl ester) which displayed active anti-plasmodial activity against 3D7 (IC50=8.41±1.25 µM; SI>100), and is moderately active against K1 (IC50=29.14±1.25 µM; SI>100). The findings demonstrate antimalarial activity of crude extracts and fractions of G. truncata involved inhibition of liver and parasite GSK3β during plasmodial infection. In addition, the results obtained indicate methyl-4-hydroxycinnamate as a promising anti-plasmodial compound and thus provide scientific evidence for the ethnomedicinal use of this plant to treat inflammation-associated diseases.,Sarjana
Pages:	164
Call Number:	QP606.P76 S839 2015
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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