1. FLAVONOID FERVER And the Charm of Chalcones

2. Wine and the French paradox The French are 2.5 times less likely than Americans to die of coronary heart disease. Regular consumption of red wine is linked to  reduced clumping of platelets;  improved cardiovascular risk profile;  increased levels of HDL’s

3. Structural Features of Naturally Occurring Bioflavonoids

4. Mechanisms of Bioactivity Flavonoids are capable of scavenging free radicals and possibly quench singlet oxygen Many naturally occurring flavonoids are capable of chelating metals and thereby preventing them from reducing H 2 O 2 in hydroxyl radical formation. Flavonoids have a synergistic effect on vitamin C and appear to stabilize ascorbic acid in human tissues

5. Plant Biosynthesis of Flavonoids

6. Crystal Structure of Quercetin

7. Reaction of Quercetin with Hydroxyl Radicals

9. Citrus limon Rutin

10. Dried peels of bitter orange tree Naringinen-7-rhamnoglucoside

11. Buchu Diosmetin

12. Marigold flower Rhamnetin

13. Milk Thistle Silybin

14. Preparation of 2’-Hydroxychalcones

15. Preparation of Chalcones by Claisen-Schmidt Condensation

16. Stereoselectivity of Condensation

17. Cyclization of 2’- Hydroxychalcones to Flavanols

18. Delocalization of  electrons in Chalcone

19. Charge Distribution in 2’-Hydroxy-4-dimethylaminochalcone

21. 4-Dimethylaminochalcone, 4-Dimethylaminochalcone, 10 -5 M in methanol

22. 10 -4 M DMAC in acidified methanol

23. 4-Dimethylaminochalcone

25. Absorbances of some Chalcones in the UV and IR

27. Features of Strong Hydrogen Bonding The pKa of the hydrogen donor is similar to the conjugate acid of the hydrogen acceptor; The energy barrier to proton transfer diminishes as the distance between the heteroatoms involved in hydrogen-bonding is reduced to value less than the sum of the van der Waals radii: < 255 pm for O-H-O and < 265 pm for O-H-N); H NMR chemical shifts for participating proton is far downfield (typically in the range of 16 to 20 ppm).

28. Crystallographic Data for 2’-Hydroxy-4-dimethylaminochalcone