Design, Synthesis, and Biological Testing of Pyrazoline Derivatives of Combretastatin-A4: A Quest for Anticancer, Anti-Inflammatory, and Antioxidant Agents

Three groups of novel analogs of combretastatin-A4 (CA-4), viz., the N¹-phenyl-pyrazoline (5a–e), N¹-alkyl acetylated pyrazoline (6a–c), and N¹-phenyl acetylated pyrazoline (7a–g) were designed, and synthesized in good yield. The structure of the compounds was confirmed by spectroscopic techniques. All the compounds were evaluated for their in vitro anticancer (MCF-7 cell line), antioxidant (DPPH, NO, SOR, and H₂O₂), and anti-inflammatory activity. Compounds 5d, 7g, 7f, 7e, 7c, 5b, 6a, 7b, and 7a showed excellent potency with GI₅₀ ranging from 0.1 to 10.9 µM against the MCF-7 cell line. Compounds 7f, 7g, 5c, 5d, 5b, 7e, and 6a exhibited good anti-inflammatory activity. Encouraged by these results, all the compounds were also tested for their antioxidant potency. Compounds 6a, 6c, 7b, 7c, 7f, and 7g were found to be excellent scavengers of all four free radicals (DPPH, NO, SOR, and H₂O₂).