Sains Malaysiana 40(5)(2011): 481–487

Kesan Suplimentasi Tokotrienol dan Tokoferol ke atas Perubahan Status Oksidatif Hepar dan Aktiviti Enzim Antioksidan Tikus Aruhan Stres

(Effects of Tocotrienol and Tocopherol Supplementation on Liver Oxidative Status and Antioxidant Enzymes Activity in Stress-Induced Rats)

Nur Azlina Mohd. Fahami* & Muharani Tajudin

Jabatan Farmakologi, Fakulti Perubatan, Universiti Kebangsaan Malaysia

Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia

Diserahkan: 5 Januari 2010 / Diterima: 20 Mei 2010

ABSTRAK

Kajian ini telah dijalankan untuk menentukan kesan suplimentasi tokotrienol (TT) dan tokoferol (TF) ke atas status oksidatif dan aktiviti enzim antioksidan pada hepar tikus dalam keadaan stres. Sebanyak 24 ekor tikus Sprague-Dawley jantan telah dibahagikan secara rawak kepada empat kumpulan. Dua kumpulan kawalan, kumpulan stres (CS) dan kumpulan tanpa stres (C) serta dua kumpulan rawatan yang diberikan tokotrienol (TTS) atau tokoferol (TFS) secara oral paksaan pada dos 60 mg/kg berat badan selama 28 hari dan didedahkan kepada stres. Setelah tamat tempoh rawatan, tikus-tikus daripada kumpulan CS, TTS dan TFS telah didedahkan kepada stres restain selama dua jam sehari untuk empat hari berturut-turut. Kemudian, darah tikus diambil untuk menentukan aktiviti enzim antioksidan iaitu superoksid dismutas (SOD) dan glutation peroksidase (GPx) manakala hepar diambil untuk menentukan kandungan malondialdehid (MDA) dan tahap glutation. Hasil kajian mendapati kandungan MDA meningkat dan glutation menurun secara signifikan pada tisu hepar pada kumpulan CS setelah diaruh stres, berbanding kumpulan tanpa stres. Walau bagaimanapun, tikus yang diberi suplimentasi tokotrienol dan tokoferol menunjukkan penurunan signifikan kandungan MDA dan peningkatan glutation berbanding kumpulan kawalan. Keputusan kajian ini mencadangkan bahawa tokotrienol dan tokoferol mampu menghalang tekanan oksidatif pada hepar akibat stres. Hasil daripada kajian ini juga menunjukkan peningkatan yang signifikan dalam aktiviti GPx plasma tikus pada kumpulan CS. Kumpulan tikus yang disuplimentasikan dengan tokotrienol menunjukkan penurunan yang signifikan dalam aktiviti GPx berbanding kumpulan CS. Sebagai kesimpulan, tokotrienol dan tokoferol berkesan dalam mengurangkan status oksidatif pada hepar tikus dan ini dapat diperhatikan dengan peningkatan glutation hepar dan penurunan aktiviti GPx plasma tikus yang teraruh stres.

Kata kunci: Stres oksidatif; stres restrain; tokeferol; tokotrienol; hepar

ABSTRACT

This study was designed to investigate the effects of tocotrienol (TT) and tocopherol (TF) supplementation on oxidative status and antioxidant enzymes activity in stress-induced rats. Twenty-four male Sprague-Dawley rats were randomly assigned into four groups, consisted of two control groups (C and CS) which were fed with a commercially prepared normal rat diet while two treatment groups (TTS and TFS) were given tocotrienol or tocopherol orally in the dose of 60 mg/kg body weight. After 28 days of treatment, the CS, TTS and TFS rats were subjected to restraint stress, two hours daily for four consecutive days. The rats were killed and their blood was taken to determine the antioxidant enzymes activity; superoxide dismutase (SOD) and glutathione peroxidase (GPx). The liver was taken to determine malondialdehyde (MDA) and glutathione levels. The findings showed that CS rats after being stressed had significantly higher levels of MDA and lower levels of glutathione in the liver. Tocotrienol and tocopherol were proved to significantly reduce the MDA and increased the glutathione content in tissues after exposure to stress compared to control groups. The findings also showed that the activity of GPx in plasma increased significantly in the CS group. However, rats fed with tocotrienol showed reduced GPx activity compared to the CS group. In conclusion, tocotrienol and tocopherol are capable of reducing the oxidative stress by reducing MDA tissue level, increasing glutathione tissue level and reducing GPx plasma activity in stress-induced rats.

Keywords: Oxidative stress; restraint stress; tocopherol; tocotrienol; liver

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*Pengarang untuk surat-menyurat; email: nazlina@medic.ukm.my