In Silico Screening of Flavonoids From Cycas as Potential Aromatase Inhibitors for Breast Cancer Therapy and Estimation of Total Flavonoid Content and LC-MS Analysis of Cycas revoluta Extract.

This study evaluated 20 flavonoids/biflavonoids from Cycas as potential inhibitors of human placental aromatase (Protein Data Bank PDB ID: 3S79), a key enzyme in estrogen receptor (ER)-positive breast cancer. Using molecular docking, absorption, distribution, metabolism, and excretion (ADME) analysis, molecular dynamics (MD) simulations (100 ns, GROMACS 2020), molecular mechanics/Poisson-Boltzmann surface area (MM-PBSA), and density functional theory (DFT) studies, biflavonoids 13, 14, and 16 exhibited stronger binding at active and preferred binding sites than flavonoids, forming stable interactions with favorable binding energies. ADME results indicated good pharmacokinetic profiles. MM-PBSA free energies were -275.84 ± 20.40, -245.87 ± 13.60, and -172.30 ± 18.51 kJ/mol, confirming stability. DFT (B3LYP/6-31+G(d,p)) provided insights into structural and electronic properties. Total flavonoid content (TFC) of Cycas revoluta leaves was determined via the aluminum chloride method, yielding 130.65 ± 3.91 mg quercetin equivalent (QE)/g (methanol) and 112.79 ± 3.38 mg QE/g (ethyl acetate), aligning with reported aromatase inhibition. Liquid chromatography-mass spectrometry (LC-MS) of the methanolic extract identified constituent flavonoids and biflavonoids. Findings suggest biflavonoids possess superior inhibitory potential, supporting their development as natural aromatase inhibitors.