The present invention provides a novel composition of matter comprised of a mixture of two specific classes of compounds--Free-B-ring flavonoids and flavans--for use in the prevention and treatment of diseases and conditions mediated by the COX-2 and 5-LO pathways. The present invention further provides a novel method for simultaneously inhibiting the cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LO) enzymes, and reducing cox-2 mRNA production. Finally, the present invention includes a method for weight loss and blood glucose control. The methods of this invention are comprised of administering to a host in need thereof an effective amount of the composition of this invention together with a pharmaceutically acceptable carrier. This invention relates generally to the prevention and treatment of diseases and conditions mediated by the cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LO) pathways, including but not limited to the relief joint discomfort and pain associated with conditions such as osteoarthritis, rheumatoid arthritis, and other injuries that result from overuse.