Inhibition of pancreatic cholesterol esterase reduces cholesterol absorption in the hamster

BACKGROUND: Pancreatic cholesterol esterase has three proposed functions in the intestine: 1) to control the bioavailability of cholesterol from dietary cholesterol esters; 2) to contribute to incorporation of cholesterol into mixed micelles; and 3) to aid in transport of free cholesterol to the enterocyte. Inhibitors of cholesterol esterase are anticipated to limit the absorption of dietary cholesterol. RESULTS: The selective and potent cholesterol esterase inhibitor 6-chloro-3-(1-ethyl-2-cyclohexyl)-2-pyrone (figure 1, structure 1) was administered to hamsters fed a high cholesterol diet supplemented with radiolabeled cholesterol ester. Hamsters were gavage fed (3)H-labeled cholesteryl oleate along with inhibitor 1, 0–200 micromoles. Twenty-four hours later, hepatic and serum radioactive cholesterol levels were determined. The ED(50 )of inhibitor 1 for prevention of the uptake of labeled cholesterol derived from hydrolysis of labeled cholesteryl oleate was 100 micromoles. The toxicity of inhibitor 1 was investigated in a 30 day feeding trial. Inhibitor 1, 100 micromoles or 200 micromoles per day, was added to chow supplemented with 1% cholesterol and 0.5% cholic acid. Clinical chemistry urinalysis and tissue histopathology were obtained. No toxicity differences were noted between control and inhibitor supplemented groups. CONCLUSIONS: Inhibitors of cholesterol esterase may be useful therapeutics for limiting cholesterol absorption

Uncharged isocoumarin-based inhibitors of urokinase-type plasminogen activator

BACKGROUND: Urokinase-type plasminogen activator (uPA) plays a major role in extracellular proteolytic events associated with tumor cell growth, migration and angiogenesis. Consequently, uPA is an attractive target for the development of small molecule active site inhibitors. Most of the recent drug development programs aimed at nonpeptidic inhibitors targeted at uPA have focused on arginino mimetics containing amidine or guanidine functional groups attached to aromatic or heterocyclic scaffolds. There is a general problem of limited bioavailability of these charged inhibitors. In the present study, uPA inhibitors were designed on an isocoumarin scaffold containing uncharged substituents. RESULTS: 4-Chloro-3-alkoxyisocoumarins were synthesized in which the 3-alkoxy group contained a terminal bromine; these were compared with similar inhibitors that contained a charged terminal functional group. Additional variations included functional groups attached to the seven position of the isocoumarin scaffold. N- [3-(3-Bromopropoxy)-4-chloro-1-oxo-1H-isochromen-7-yl]benzamide was identified as an uncharged lead inhibitor of uPA, K(i )= 0.034 μM. Molecular modeling of human uPA with these uncharged inhibitors suggests that the bromine occupies the same position as positively charged arginino mimetic groups. CONCLUSION: This study demonstrates that potent uncharged inhibitors of uPA can be developed based upon the isocoumarin scaffold. A tethered bromine in the three position and an aromatic group in the seven position are important contributors to binding. Although the aim was to develop compounds that act as mechanism-based inactivators, these inhibitors are competitive reversible inhibitors

Inhibition of Nuclear Factor κB Activation and Cyclooxygenase-2 Expression by Aqueous Extracts of Hispanic Medicinal Herbs

Nonsteroidal anti-inflammatory drugs (NSAIDs) are a primary choice of therapy for diseases with a chronic inflammatory component. Unfortunately, long-term NSAID therapy is often accompanied by severe side effects, including cardiovascular and gastrointestinal complications. Because of this, there is critical need for identification of new and safer treatments for chronic inflammation to circumvent these side effects. Inflammatory diseases have been successfully remedied with natural herbs by many cultures. To better understand the potential of natural herbs in treating chronic inflammation and to identify their mechanism of action, we have evaluated the anti-inflammatory activities of 20 medicinal herbs commonly used in the Hispanic culture. We have established a standardized method for preparing aqueous extracts (teas) from the selected medicinal herbs and screened for inhibition of tumor necrosis factor-α-induced activation of nuclear factor κB (NF-κB), which is the central signaling pathway of the inflammatory response. A number of herbal teas were identified that exhibited significant anti-inflammatory activity. In particular, tea from the herb commonly called laurel was found to be an especially potent inhibitor of NF-κB-dependent cyclooxygenase-2 gene expression and prostaglandin E2 production in cultured murine macrophages. These findings indicate that laurel tea extract contains potent anti-inflammatory compounds that function by inhibiting the major signal transduction pathway responsible for inducing an inflammatory event. Based on these results, laurel may represent a new, safe therapeutic agent for managing chronic inflammation