Dose-Dependent Cholesterolemic Activity of Tocotrienols and α-Tocopherol
Tocotrienols and tocopherols are isoforms of vitamin E. Vitamin E may exhibit antioxidant, prooxidant and non-antioxidant activities depending upon circumstances. In this study, the effect of tocotrienols and α-tocopherol on the activities of HMG CoA reductase and cholesterol 7 α-hydroxylase was inv...
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| Format: | Article |
| Language: | English English |
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Nutrition Society of Malaysia
2002
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| Online Access: | http://psasir.upm.edu.my/id/eprint/7097/ http://psasir.upm.edu.my/id/eprint/7097/1/mjn8n2_art3.pdf |
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| author | Teik, Khor Hun Theng , Ng Theng Rajendran, Raajeswari |
| author_facet | Teik, Khor Hun Theng , Ng Theng Rajendran, Raajeswari |
| author_sort | Teik, Khor Hun |
| building | UPM Institutional Repository |
| collection | Online Access |
| description | Tocotrienols and tocopherols are isoforms of vitamin E. Vitamin E may exhibit antioxidant, prooxidant and non-antioxidant activities depending upon circumstances. In this study, the effect of tocotrienols and α-tocopherol on the activities of HMG CoA reductase and cholesterol 7 α-hydroxylase was investigated. Pure tocotrienols were isolated from palm fatty acid distillate and pure α-tocopherol was obtained commercially. Guinea pigs were treated with different dosages of tocotrienols and α-tocopherol. After the treatment period, animals were sacrificed and liver microsomes were prepared. HMG CoA reductase and cholesterol 7α-hydroxylase were assayed using tracer techniques. Our results showed that the effects of tocotrienols and α-tocopherol on the activities of both the enzymes were dose-dependent. At low dosages, both tocotrienols and α-tocopherol exhibited an inhibitory effect on both the enzymes. Moreover, tocotrienols were a much stronger inhibitors than α-tocopherol. At high dosages, on the other hand, tocotrienols and α-tocopherol showed opposite effects on the enzymes. While tocotrienols continued to exhibit an inhibitory effect, α-tocopherol actually exhibited a stimulatory effect on both the enzymes. A possible explanation for this observation is suggested.
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| first_indexed | 2025-11-15T07:28:20Z |
| format | Article |
| id | upm-7097 |
| institution | Universiti Putra Malaysia |
| institution_category | Local University |
| language | English English |
| last_indexed | 2025-11-15T07:28:20Z |
| publishDate | 2002 |
| publisher | Nutrition Society of Malaysia |
| recordtype | eprints |
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| spelling | upm-70972013-05-27T07:33:24Z http://psasir.upm.edu.my/id/eprint/7097/ Dose-Dependent Cholesterolemic Activity of Tocotrienols and α-Tocopherol Teik, Khor Hun Theng , Ng Theng Rajendran, Raajeswari Tocotrienols and tocopherols are isoforms of vitamin E. Vitamin E may exhibit antioxidant, prooxidant and non-antioxidant activities depending upon circumstances. In this study, the effect of tocotrienols and α-tocopherol on the activities of HMG CoA reductase and cholesterol 7 α-hydroxylase was investigated. Pure tocotrienols were isolated from palm fatty acid distillate and pure α-tocopherol was obtained commercially. Guinea pigs were treated with different dosages of tocotrienols and α-tocopherol. After the treatment period, animals were sacrificed and liver microsomes were prepared. HMG CoA reductase and cholesterol 7α-hydroxylase were assayed using tracer techniques. Our results showed that the effects of tocotrienols and α-tocopherol on the activities of both the enzymes were dose-dependent. At low dosages, both tocotrienols and α-tocopherol exhibited an inhibitory effect on both the enzymes. Moreover, tocotrienols were a much stronger inhibitors than α-tocopherol. At high dosages, on the other hand, tocotrienols and α-tocopherol showed opposite effects on the enzymes. While tocotrienols continued to exhibit an inhibitory effect, α-tocopherol actually exhibited a stimulatory effect on both the enzymes. A possible explanation for this observation is suggested. Nutrition Society of Malaysia 2002 Article PeerReviewed application/pdf en http://psasir.upm.edu.my/id/eprint/7097/1/mjn8n2_art3.pdf Teik, Khor Hun and Theng , Ng Theng and Rajendran, Raajeswari (2002) Dose-Dependent Cholesterolemic Activity of Tocotrienols and α-Tocopherol. Malaysian Journal of Nutrition, 8 (2). pp. 157-166. ISSN 1394-035X http://nutriweb.org.my English |
| spellingShingle | Teik, Khor Hun Theng , Ng Theng Rajendran, Raajeswari Dose-Dependent Cholesterolemic Activity of Tocotrienols and α-Tocopherol |
| title | Dose-Dependent Cholesterolemic Activity of Tocotrienols and α-Tocopherol |
| title_full | Dose-Dependent Cholesterolemic Activity of Tocotrienols and α-Tocopherol |
| title_fullStr | Dose-Dependent Cholesterolemic Activity of Tocotrienols and α-Tocopherol |
| title_full_unstemmed | Dose-Dependent Cholesterolemic Activity of Tocotrienols and α-Tocopherol |
| title_short | Dose-Dependent Cholesterolemic Activity of Tocotrienols and α-Tocopherol |
| title_sort | dose-dependent cholesterolemic activity of tocotrienols and α-tocopherol |
| url | http://psasir.upm.edu.my/id/eprint/7097/ http://psasir.upm.edu.my/id/eprint/7097/ http://psasir.upm.edu.my/id/eprint/7097/1/mjn8n2_art3.pdf |