EXPLORING THE THERAPEUTIC POTENTIAL OF ERIGERON CANADENSIS IN PRIMARY DYSMENORRHEA: MOLECULAR DOCKING AGAINST COX-2 AND A PROSPECTIVE CLINICAL STUDY

Abstract

Background: Primary dysmenorrhea is a common cause of menstrual pain among women of reproductive age and is primarily associated with increased prostaglandin-mediated uterine contractions. Erigeron canadensis L. has traditionally been used in homeopathic practice for painful menstruation, but clinical evidence and information regarding its possible molecular targets remain limited. This pilot study aimed to explore the potential interaction between E. canadensis phytoconstituents and cyclooxygenase-2 (COX-2) using molecular docking and to evaluate changes in pain intensity following administration of E. canadensis mother tincture in women with primary dysmenorrhea. Methods: The study comprised two components: an in silico molecular docking study and a prospective clinical pilot study. Phytoconstituents of E. canadensis were docked against COX-2 using the Schrödinger Glide platform, and docking scores were evaluated. The clinical component was conducted at Yenepoya Homoeopathic Medical College & Hospital from May to July 2026. Thirteen women aged 18–35 years with clinically diagnosed primary dysmenorrhea, a Visual Analogue Scale (VAS) pain score ≥4, and symptom characteristics corresponding to E. canadensis were enrolled consecutively. Participants received E. canadensis mother tincture (Q) during episodes of menstrual pain and were followed for two consecutive days. Pain intensity was assessed using the VAS at baseline, first follow-up, and second follow-up. Changes in VAS scores were analysed using the Friedman test, followed by Bonferroni-adjusted Wilcoxon signed-rank tests when appropriate. Kendall's coefficient of concordance (W) was used to estimate effect size. Results: Seven E. canadensis phytoconstituents showed favorable predicted interactions with COX-2, with reported docking scores ranging from 120.123 to 127.746. In the clinical study, the median VAS score decreased from 8.0 (IQR 6.5–8.0) at baseline to 4.0 (IQR 2.0–6.0) at the first follow-up and 0.0 (IQR 0.0–4.5) at the second follow-up. The Friedman test demonstrated a statistically significant difference in VAS scores across the three assessment points (χ²(2) = 12.19, P = 0.002), with a Kendall's W of 0.469, indicating a moderate effect. Conclusion: In this small, uncontrolled pilot study, administration of E. canadensis mother tincture was associated with a significant reduction in menstrual pain over the two-day follow-up period. Molecular docking identified favorable predicted interactions between selected E. canadensis phytoconstituents and COX-2, providing a hypothesis regarding a possible pharmacological pathway. However, docking predictions cannot establish biological activity, and the uncontrolled clinical design precludes causal inference. Larger controlled clinical studies, together with experimental validation of the predicted molecular interactions, are warranted.