Structural significance of the acyl group at the C-10 position and the A ring of the taxane core of paclitaxel for inducing nitric oxide and tumor necrosis factor production by murine macrophages.

The antitumor agent, paclitaxel (Taxol®), mimics the actions of lipopolysaccharide (LPS) on murine macrophages (Mφ). Various synthetic analogs of paclitaxel were examined for their potencies to induce nitric oxide (NO) and tumor necrosis factor (TNF) production by murine peritoneal Mφ, and by human peripheral blood cells. The benzoyl group at C-2, the hydroxy group at C-7 and the acetyl group at C-10 were found to be critically important sites to activate murine Mφ. Nor-seco-taxoid analogs lacking the A ring of the taxane core of paclitaxel were inactive, but inhibit paclitaxel- or LPS-induced NO production. All the compounds tested did not induce TNF production by human blood cells.