Pluripotent Cinnamic Acid and Valproic Acid Hybrid Molecules Designed as Strong Anti-inflammatory and Anti-hyperlipidemic Compounds

Introduction: Inflammation and oxidative stress are considered main pathophysiological factors for neuronal and cardiovascular diseases, also leading to the impairment of main cellular metabolic pathways. Promotion of hyperlipidemia is also the result of inflammatory and oxidative (ROS production) processes. Additionally, compounds of medicinal interest like valproic and caffeic acids and amino acids like proline and tyrosine have shown antiinflammatory and cellular protective potency. Methods: In the present study, amides of L-tyrosine, L-proline, and L-cysteine, and an ester of cinnamyl alcohol were synthesized by conjugation with caffeic acid, valproic acid, or (E)-3- (3,4-dimethoxyphenyl)acrylic acid (cinnamic acid derivative). This design aimed to explore the multiple activities of novel compounds, via the combination of structures related to the desired biological characteristics. The synthesized compounds were tested for their effects on oxidative stress in vitro and on acute inflammation and hyperlipidemia in vivo. Results: The synthesized compounds decreased carrageenan-induced rat paw oedema up to 69% (the most active compound 6), and 49% for compound 2, an amide of valproic acid with L-tyrosine. Several compounds were effective antioxidants, with radical scavenging and lipid peroxidation inhibitory activity. Additionally, the synthesized molecules significantly decreased the plasma lipidemic markers in tyloxapol-induced hyperlipidemic rats. They decreased plasma triglycerides and total cholesterol up to 53% and 78% (compound 1), and LDL-cholesterol up to 69% (compound 5). Discussion: The anti-inflammatory activity of the derivatives was equal to or much higher than that of ibuprofen and tolfenamic acid, two widely applied NSAIDs (nonsteroidal antiinflammatory drugs), whilst compound 2 was 3.3 times more active than valproic acid, with the latter being tested at four times higher dose. Concerning the antioxidant activity, several compounds were comparable to the strong antioxidant Trolox, and the effect on cholesterol levels for all the derivatives was comparable to or equal to simvastatin a 3-hydroxy-3-methylglutaryl (HMG) coenzyme A reductase inhibitor. Conclusion: The multiple activities of the synthesized compounds may serve for the manipulation of conditions involving inflammation and lipid deregulation, or the further optimization and production of compounds towards these ailments.