Novel 3,19‐(N‐phenyl‐3‐(4‐fluorophenyl)‐pyrazole) Acetal of Andrographolide Promotes Cell Cycle Arrest and Apoptosis in MDA‐MB‐231 Breast Cancer Cells

Natural products have been crucial in cancer treatment due to their ability to selectively target cancer cells. Andrographolide, a major bioactive compound from the plant Andrographis paniculata, and its derivatives exhibited potential anticancer properties. As nitrogen-containing heteroaromatic compounds, particularly pyrazole derivatives, are key building blocks in the design of anticancer drugs, the primary focus of this study was to blend the pyrazole pharmacophore and andrographolide. In this work, twenty novel 3,19-(N-phenyl-3-aryl-pyrazole) acetals of andrographolide and isoandrographolide were synthesized and characterized using UV-Vis, FT-IR, NMR, and HRMS. Following initial screening for anticancer activity against 60 human cancer cell lines at NCI, USA, compound 1f (R=4-F) was selected for detailed in vitro analysis on the breast cancer cell line MDA-MB-231. MTT assay results demonstrated that compound 1f exhibited strong, dose-dependent anti-proliferative effects. Apoptotic assay revealed a progressive increase in apoptotic cells upon treatment with 1f. Additionally, cell cycle analysis indicated that 1f caused G1/M phase arrest in MDA-MB-231 cells. The synthesized compounds were also tested for antioxidant activity using the DPPH assay, and compounds 1b (R=3-NO₂, 60.68%) and 2b (R=3-NO₂, 61.17%) showed the strongest radical scavenging activity. Finally, the most promising compounds were subjected to in-silico Lipinski’s assessments to evaluate their potential as lead candidates.