Ursolic acid and other pentacyclic triterpenoids stimulate intestinal alkaline sphingomyelinase in vitro
✍ Scribed by David Andersson; Åke Nilsson; Rui-Dong Duan
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 188 KB
- Volume
- 108
- Category
- Article
- ISSN
- 1438-7697
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✦ Synopsis
Abstract
Purpose: Alkaline sphingomyelinase (alk‐SMase) is an enzyme that hydrolyses sphingomyelin in a bile salt‐dependent manner in the gastrointestinal tract, and has been proposed as an inhibitor of colon carcinogenesis. Ursolic acid (UA) is a plant‐derived pentacyclic triterpenoid that has been shown to have anti‐proliferative and apoptotic effects on HT29 human colon adenocarcinoma cells, with activation of alk‐SMase as an early event. The aim of this study was to study the in vitro effects of UA and its analogues on the activity of purified rat intestinal alk‐SMase. Methods: Rat intestinal alk‐SMase activity was determined after incubation with UA in the presence and absence of taurocholate (TC). The effect was compared with boswellic acids, another group of pentacyclic triterpenoids. Results: UA enhanced the activity of rat intestinal alk‐SMase in a dose‐dependent manner, without a similar effect on bacterial neutral SMase. Four types of boswellic acid also increased the enzyme activity, with the effect of acetyl‐keto‐β‐boswellic acid being most potent. Activation of alk‐SMase by TC at a low concentration (0.4 mM), but not at a high concentration, was enhanced by UA. Conclusions: Ursolic acid and four types of boswellic acid, all pentacyclic triterpenoids, have a stimulatory effect on the activity of intestinal alk‐SMase.