The results of in silico screening of the 50 isolated compounds from Millettia dielsiana against the target proteins PDE4 (PDE4A, PDE4B, and PDE4D) showed binding affinity ranges from −5.81 to −11.56, −5.27 to −13.01, and −5.80 to −12.12 kcal mol−1, respectively, with median values of −8.83, −8.84, and −8.645 kcal mol−1, respectively. Among these compounds, Millesianin F was identified as the most promising PDE4A inhibitor due to its strongest binding affinity with the target protein PDE4A. (−11.56 kcal mol−1). This was followed by the compound 5,7,4′-trihydroxyisoflavone 7-O-β-d-apiofuranosyl-(1→6)-β-d-glucopyranoside (D50) with the binding affinity value of −11.35 kcal mol−1. For the target protein PDE4B, compound D50 exhibited the strongest binding affinity value of −13.01 kcal mol−1, while showing poorer inhibition ability for PDE4D. The 100 ns MD simulation examination (radius of gyration, Solvent Accessible Surface Area (SASA), Root-Mean-Square Deviation (RMSD), Root-Mean-Square Fluctuation (RMSF), and hydrogen bonding) was carried out to examine the overall stability and binding efficiency of the protein–ligand complex between compounds (Millesianin F, Millesianin G, Claclrastin-7-O-β-d-glucopyranoside, 7-hydroxy-4′,6 dimethoxyisoflavone-7-O-β-d-apiofuranosyl-(1→6)-β-d-glucopyranoside, 7-hydroxy-4′,8-dimethoxyisoflavone 7-O-β-d-apiofuranosyl-(1→6)-β-d-glucopyranoside, Odoratin-7-O-β-d-glucopyranoside, and 5,7,4′-trihydroxyisoflavone 7-O-β-d-apiofuranosyl-(1→6)-β-d-glucopyranoside) and PDE4 (A, B) subtype proteins. Compound D50 has shown strong anti-inflammatory activity, as evidenced by experimental results. It effectively inhibits PDE4B and PDE4D, with IC50 values of 6.56 ± 0.7 µM and 11.74 ± 1.3 µM, respectively. Additionally, it reduces NO production, with an IC50 value of 5.40 ± 0.9 µM. Based on these findings, it is promising and considered a potential novel anti-inflammatory drug for future development.