Spiro-fused indoline-quinazoline hybrids as smart bombs against TNF-α-mediated inflammation

Inflammation is central to numerous diseases, highlighting the need for new anti-inflammatory agents. This study explores the potential of novel spirofused indoline-quinazoline hybrids (4a-p) as anti-inflammatory compounds, inspired by a spiroisatin analogue (VI) that showed modest TNF-α inhibition. We aimed to enhance activity by modifying the isatin scaffold: first, introducing N-alkylation (propyl, butyl, or isobutyl) to improve hydrophobic interactions within the TNF-α dimer active site; second, adding halogens (F, Cl, Br) at the 5-position to increase lipophilicity. Anti-inflammatory activity against TNF-α was confirmed in-vivo for all synthesized analogues, with 4b, 4e, 4k, and 4n emerging as the top candidates. Further studies on these four compounds assessed their analgesic effects, as well as their impact on PGE₂, NF-κB, paw thickness, and paw weight. In-vitro analyses revealed nanomolar TNFR2-TNF-α binding inhibition for the four leads. Safety evaluations included histopathology, ulcerogenic potential, kidney and liver functions, and acute hemotoxicity. In-silico studies examined drug-likeness, pharmacokinetics, and TNF-α dimer interactions. These results suggest that the four lead compounds possess promising profiles compared to standard therapies.