Planta Med 2006; 72(3): 267-269
DOI: 10.1055/s-2005-916178
Letter
© Georg Thieme Verlag KG Stuttgart · New York

Inhibition of Diacylglycerol Acyltransferase by Betulinic Acid from Alnus hirsuta

Mi Yeon Chung1 , Mun-Chual Rho1 , Seung Woong Lee1 , Hye Ran Park1 , Koanhoi Kim2 , In Ah Lee3 , Dong Hyun Kim3 , Kyung Hee Jeune4 , Hyun Sun Lee1 , Young Kook Kim1
  • 1Laboratory of Lipid Metabolism, Korea Research Institute of Bioscience and Biotechnology, Daejon, Korea
  • 2College of Medicine, Pusan National University, Pusan, Korea
  • 3College of Pharmacy, Kyung-Hee University, Seoul, Korea
  • 4Department of Biology, Yeungnam University, Kyungsan, Korea
Further Information

Publication History

Received: May 3, 2005

Accepted: July 22, 2005

Publication Date:
05 December 2005 (online)

Abstract

During the screening for diacylglycerol acyltransferase (DGAT) inhibitors from natural products, the lupane-type triterpenoid betulinic acid was isolated from the methanol extract of Alnus hirsuta. It potently inhibited DGAT in the rat liver microsomes with an IC50 value of 9.6 μM. Enzyme kinetic studies showed apparent Km and Ki values of 13.3 μM and 8.1 μM using [14 C]oleoyl-CoA as a substrate. A decrease in the apparent Vmax was observed with betulinic acid, whereas the apparent Km remained constant. Therefore, a Lineweaver-Burk plot of DGAT inhibition by betulinic acid showed a non-competitive type of inhibition. In the cell-based assay, betulinic acid inhibited triglyceride (TG) formation by human HepG2 cells. These findings suggest that betulinic acid may be a potential lead compound in the treatment of obesity.

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Dr. Hyun Sun Lee

Laboratory of Lipid Metabolism

Korea Research Institute of Bioscience and Biotechnology

52 Oun-dong

Yusong-gu

Daejon 305-333

Korea

Phone: +82-42-860-4314

Fax: +82-42-861-2675

Email: leehs@kribb.re.kr