Synthesis, crystal studies and biological evaluation of flavone derivatives.

Three substituted flavone derivatives have been synthesized from substituted O-hydroxy acetophenones and 4-trifluoromethyl benzaldehyde in good yield. These compounds were characterized by NMR spectroscopy and single crystal X-ray Diffraction. Compound F1 and F3 were re-crystallized from their concentrated solutions in chloroform ethyl acetate mixture while F2 was re-crystallized in ethyl acetate n-hexane mixture. Compound F1 and F3 are monoclinic (space group P21/c) with lattice parameters: [a, b, c (A) / ß (°)] = 13.332 (2), 15.616 (2) / 6.2898 (8) and 13.9716 (15), 7.1868 (7), 13.6912 (14) / 91.113(6) respectively. Compound F2 is Triclinic (space group P-1) and has lattice parameters: [a, b, c (Å) / α, ß, γ (°)] = 6.5002 (6), 8.3801 (9), 13.5989 (14) / 89.348(5), 85.141(4), 84.521(5). Antioxidant, antibacterial and cytotoxic profile was investigated. The compounds showed moderate to less activity on 1,1-diphenyl-2-picryl-hydrazyl (DPPH), Hydrogen peroxide (H/2/O/2) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) models of radical scavenging activity while promising antibacterial potentials were recorded. Furthermore, these molecules can also be used as potential candidates for new antitumor agents.

A possible mechanistic approach of synthetic flavonoids in the management of pain.

Flavonoids are phenolic compounds that have always attracted pharmaceutical researchers and food manufacturers. Nature has indirectly provided us flavones in our daily diet i.e. tea, fruits, juices and vegetables. Flavones have got special position in research field of natural and synthetic organic chemistry due to their biological capabilities. Three substituted flavone derivatives have been synthesized from substituted O-hydroxy acetophenones and 4-trifluoromethyl benzaldehyde in good yield. The structures have been established by different spectroscopic techniques like 1HNMR 13CNMR, IR spectroscopy. The compounds were then screened for their enzyme inhibition potential and antinociceptive response in mice models with writhings induced by acetic acid, tail immersion and formalin-induced nociception assay procedures and structure activity relationship was established. The effects following pretreatment with naloxone were also studied to reveal the involvement of opioid receptors in the antinociceptive action. The flavone derivatives showed moderate to weak inhibition against LOX. Moreover, significant to moderate decrease in the number of abdominal constrictions, increase in paw-licking response time in both phases and a significant raise in latency time in nociception models. Moreover, the antinociceptive response was significantly attenuated by pretreatment with opioid receptor antagonist suggesting the involvement of opioidergic system in the analgesic action. The flavone derivatives showed analgesic response in all models of nociception suggesting the possible involvement of opioidergic system in the antinociceptive action.