Exploration of essential structure of malloapelta B for the inhibitory activity against TNF induced NF-kappaB activation

• Published in: Archives of pharmacal research 2006-10, Vol.29 (10), p.840
• Main Authors: Van Luu, Chinh, Van Chau, Minh, Lee, Jung-Joon, Jung, Sang-Hun
• Format: Article
• Language: English
• Subjects: Alkaline Phosphatase - genetics; Alkaline Phosphatase - metabolism; Benzopyrans - chemistry; Benzopyrans - pharmacology; Cell Survival - drug effects; Chromans - chemistry; Chromans - pharmacology; Euphorbiaceae - chemistry; Female; HeLa Cells; Humans; Hydrogenation; Inhibitory Concentration 50; Magnetic Resonance Spectroscopy - methods; Molecular Structure; NF-kappa B - drug effects; NF-kappa B - genetics; NF-kappa B - metabolism; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; Spectrophotometry, Infrared - methods; Time Factors; Transfection; Tumor Necrosis Factor-alpha - antagonists & inhibitors; Tumor Necrosis Factor-alpha - pharmacology
• ISSN: 0253-6269

For the exploration of pharmacophoric moiety of malloapelta B (1) possessing the inhibitory activity of NF-kappaB activation, structural variation of alpha,beta-unsaturated carbonyl motif was attempted. 1 was reduced by catalytic hydrogenation, sodium borohydride, and lithium aluminumhydride. Catalytic hydrogenation with 30 psi or 15 psi of H2 gas of 1 generated 8-butyl-5,7-dimethoxy-2,2-dimethylchroman (2) and 1-(5,7-dimethoxy-2,2-dimethylchroman-8-yl)butan-1-one (3), respectively. Reduction with sodium borohydride occurred at the double bond of alpha,beta-unsaturated ketone of 1 to give 1-(5,7-dimethoxy-2,2-dimethyl-2H-chromen-8-yl)butan-1-one (4). Reduction of 1 with lithium aluminumhydride and then quenched with methanol and water produced unexpected products, 1-(5,7-dimethoxy-2,2-dimethyl-2H-chromen-8-yl)-3-methoxy-1-butene (5) and 1-(5,7-dimethoxy-2,2-dimethyl-2H-chromen-8-yl)-3-hydroxy-l-butene (6). These are formed from the isomerization of initial product 9 through the continuous conjugate carbocation intermediate 11. Addition of ethylmagnesium bromide and dimethyl malonate anion to 1 gave the conjugate adducts 7 and 8. Ethylmagesium bromide and sodium borohydride reduction unusually gave the conjugate addition due to steric congestion around carbonyl group of 1. Compound 2 exhibits the reduced inhibitory activity against NF-kappaB activation and the others do not show the activity. Therefore alpha,beta-unsaturated carbonyl group of 1 should be important for its inhibitory activity.