Date Palm Pollen (Phoenix dactylifera L.) Phytoestrogens as Natural Modulators of Estrus in Goats: A Molecular and Phytochemical Insight

Reproductive management in goats remains challenging due to seasonal breeding and the use of hormones that raise concerns about immunogenicity, cost, sustainability, and animal welfare. In this study, we evaluated date palm pollen (Phoenix dactylifera L.) (DPP) as a natural source of estrogenic compounds capable of modulating reproductive function. DPP was extracted using methanol, ethanol, acetone, and hexane, and the extracts were analyzed by ultra-performance liquid chromatography. Quercetin and coumestrol were detected in the methanolic and ethanolic extracts at comparable levels (quercetin 0.043–0.044 mg/g; coumestrol 0.987–1.015 mg/g of extract) (p > 0.05). The acetone extract contained significantly lower concentrations (quercetin 0.017 mg/g; coumestrol 0.033 mg/g of extract), while the hexane extract showed no detectable amounts. Molecular docking using the crystallographic structure of estrogen receptor alpha (PDB:6PIT) showed that both compounds interact with key residues of the receptor’s ligand-binding domain. Coumestrol exhibited the highest affinity (−9.3 kcal/mol), surpassing 17-β estradiol (−8.9 kcal/mol), forming several hydrogen bonds and hydrophobic contacts. Quercetin showed a lower affinity (−7.2 kcal/mol) but maintained stabilizing interactions compatible with partial agonist activity. Overall, methanol and ethanol were the most effective solvents for extracting phytoestrogens from DPP, and the findings support their potential as natural alternatives to hormones for estrus induction in goats.