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Title:	Kesan antihiperglisemia in vivo dan in vitro fraksi gynura procumbens
Authors:	Chong Ching June (P54239)
Supervisor:	Hasidah Mohd Sidek, Prof. Madya Dr.
Keywords:	antihiperglisemia Diabetes
Issue Date:	14-Sep-2013
Description:	Gynura procumbens, sejenis tumbuhan ubatan yang lazimnya dikenali sebagai Sambung Nyawa digunakan secara meluas di Asia Tenggara untuk meringankan simptom pelbagai penyakit termasuk diabetes melitus. Kesan pengurangan glukosa darah oleh G. procumbens yang telah dilaporkan berkemungkinan disebabkan keupayaan G. procumbens untuk memberikan kesan menyerupai insulin pada peringkat sel. Kajian ini bertujuan untuk menilai kesan antihiperglisemia fraksi-fraksi daripada ekstrak etanol G. procumbens serta menentukan penglibatan glikogen sintase kinase (GSK3), satu komponen utama pengisyaratan insulin dalam aktiviti antihiperglisemia. Pemberian secara oral fraksi n-heksana, etil asetat, n-butanol G. procumbens (250 mg/kg b.t.) selama 14 hari kepada tikus diabetis aruhan-STZ mengurangkan aras glukosa darah masing-masing sebanyak 30.0, 60.3 dan 30.9% (P<0.05) berbanding kawalan diabetes. Pemberian drug rujukan antidiabetis, glibenklamida (5 mg/kg b.t) mengurangkan aras glukosa darah sebanyak 61.4%. Kandungan glikogen hepar tikus diabetis yang diperlakukan dengan ketiga-tiga fraksi G. procumbens didapati meningkat (P<0.05) selepas 14 hari perlakuan. Analisis pemblotan Western juga menunjukkan GSK3β dalam hepar tikus diabetis yang diperlakukan dengan fraksi-fraksi G. procumbens atau glibenklamida adalah dalam keadaan terfosfat pada Ser9. Secara keseluruhannya, hasil kajian ini menunjukkan tindakan antihiperglisemia fraksi G. procumbens mengakibatkan penyahaktifan GSK3β dalam hepar tikus diabetis. Pemencilan lapan puncak HPLC diperolehi daripada fraksi etil asetat G. procumbens. Daripada lapan puncak, satu sebatian bioaktif dikenalpasti sebagai kaempferol menggunakan analisis NMR. Kajian in vitro menggunakan sel HepG2 kultur dalam medium glukosa 25 mM menunjukkan bahawa perlakuan dengan fraksi etil asetat G. procumbens, kaempferol atau metformin merangsang pengambilan glukosa dalam keperluan dos-bersandar berbanding kawalan diabetes. Analisis Western juga menunjukkan bahawa pemfosfatan GSK3β (Ser9) dikesan dalam sel HepG2 hiperglisemia dengan perlakuan metformin (50 μg/mL), fraksi etil asetat G. procumbens (1000 μg/mL) dan kaempferol (30 μg/mL). Memandangkan aktiviti anti-GSK3 tidak hadir dalam fraksi G. procumbens seperti dilaporkan dalam kajian lain, justeru itu tindakan antihiperglisemia fraksi-fraksi yang diperhatikan berkemungkinan berkait secara langsung atau tidak dengan kesan juzuk fitokimia terhadap komponen huluan GSK3 dalam tapak jalan pengisyaratan insulin.,Gynura procumbens, a medicinal plant locally known as Sambung Nyawa, is widely used traditionally in South East Asia to alleviate symptoms of various ailments including diabetes. The reported blood glucose-reducing effect of G. procumbens may be attributed to its insulin-like effects at the cellular level. The present study aimed to evaluate the antihyperglcemic effect(s) of fractions prepared from ethanolic extract of G. procumbens and to ascertain the involvement of glycogen synthase kinase (GSK3), a key component of insulin biosignaling in the antihyperglycemic activity. Oral administrations of n-hexane, ethyl acetate and n-butanol fractions of G. procumbens (250 mg/kg b.w.) for 14 days in STZ-induced diabetic rats each reduced blood glucose levels by 30.0, 60.3 and 30.9% (P<0.05) respectively compared to diabetic controls. Administration of the reference antidiabetic drug, glibenclamide (5 mg/kg b.w.) reduced blood glucose levels by 61.4%. Liver glycogen contents in diabetic rats were elevated (P<0.05) following administrations of the three fractions for 14 days. Western analysis also showed that GSK3 in the livers of G. procumbens fractionstreated or glibenclamide-treated animals were phosphorylated at Ser9. The above findings indicated that the antihyperglycemic effects of G. procumbens fractions resulted in the inactivation of GSK3β in liver of diabetic rats. Eight HPLC separated peaks were obtained from ethyl acetate fraction of G. procumbens. Out of the eight peaks, one bioactive compound was identified as kaempferol using NMR analysis. In vitro studies using HepG2 cells cultured in 25 mM glucose medium showed that treatment with ethyl acetate fraction of G. procumbens, kaempferol or metformin stimulated glucose uptake in a dose-dependent manner as compared to diabetic controls. Western analysis also demonstrated that phosphorylated GSK3β (Ser9) was detected in hyperglycemic HepG2 cells treated with metformin (50 μg/mL), ethyl acetate fraction of G. procumbens (1000 μg/mL) and kaempferol (30 μg/mL). Given that anti-GSK3 activity is absent in the G. procumbens fractions as reported elsewhere, it is therefore possible that the antihyperglycemic action of the fractions observed here was related to direct or indirect effects of phytochemical constituents on components upstream of GSK3 in the insulin biosignaling pathway.,Master/Sarjana
Pages:	113
Call Number:	RC660.C456 2013 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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