Bello, Idris
(2015)
Evaluation Of The Cardiovascular Activity And Toxicity Study Of Alstonia Scholaris Bark Extracts.
Masters thesis, Universiti Sains Malaysia.
Abstract
Tujuan kajian ini adalah untuk memeriksa kesan antihipertensi ekstrak kulit kayu Alstonia
scholaris (pulai) dan mekanisme tindakan farmakologinya. Pengekstrakan berturut-turut
telah dijalankan untuk mendapatkan ekstrak metanol (ASME) dan air (ASWE) yang
diperolehi selepas penyahlemakan dengan eter petroleum. Kesan antihipertensi ekstrak ini
telah dinilai pada tikus hipertensi spontan (SHR). Pemberian ASME secara oral setiap hari
(1000 mg/kg selama 2 minggu) mempamerkan penurunan ketara tekanan darah (p <0.05)
tikus berbanding SHR kawalan. Melalui teknik fraksinasi cecair-cecair, ASME telah
difraksikan berturut-turut menggunakan diklorometana, etil asetat dan n-butanol. Semua
fraksi (0.125 – 4 mg/mL) menunjukkan vasorelaksi bergantung dos pada sediaan cincin aorta
yang telah diprakontraksikan dengan fenileferina (PE; 1 μM) atau kalium klorida (80 mM).
Fraksi n-butanol (NBF-ASME) merupakan fraksi yang paling poten (Rmax = 106.4 ± 0.045%).
Prainkubasi cincin aorta dengan NBF-ASME (0.5, 1 dan 2 mg/mL) merencat tindak balas
kontraksi cincin aorta yang diaruhkan PE dengan ketara (p <0.05-0.001). Pembuangan
endotelium dan inkubasi dengan L-NAME, indometasin, atropina dan propranolol tidak
menjejaskan dengan ketara relaksi oleh NBF-ASME.
The aim of the present study was to investigate the antihypertensive effect of Alstonia
scholaris (pulai) bark extracts and its pharmacological mechanism of actions. Successive
extraction was carried out to obtain methanol (ASME) and water (ASWE) extract of the bark
after defatting with petroleum ether. The antihypertensive effect of these extracts were
evaluated on spontaneous hypertensive rats (SHR). Daily oral administration of ASME (1000
mg/kg for 2 weeks) exhibited a significant decrease in the blood pressure (p < 0.05) of the
rats compared to control SHR. By means of liquid-liquid fractionation technique, the aqueous
ASME solution was successively fractionated using dichloromethane, ethyl acetate and nbutanol.
All the fractions (0.125 – 4 mg/mL) gave a dose-dependent vasorelaxation on aortic
ring preparations pre-contracted with phenylephrine (PE; 1 μM) or potassium chloride (80
mM). The n-butanol fraction (NBF-ASME) was the most potent fractions (Rmax = 106.4 ±
0.045 %). Pre-incubation of aortic rings with NBF-ASME (0.5, 1 and 2 mg/mL) significantly
inhibit the contractile response of the aortic rings to PE-induced contraction (p<0.05-0.001).
Removal of endothelium and incubation with L-NAME, indomethacin, atropine, and
propranolol did not significantly affect the relaxation effect of NBF-ASME.
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