Assessment of the Anthelmintic Efficacy of Rhododendron arboreum Flower Extract Using an In Vitro Model

Background: Helminth infections remain an important public health concern, particularly in regions with inadequate sanitation and limited access to healthcare. Medicinal plants contain diverse phytochemicals that may serve as potential sources of biologically active compounds. Rhododendron arboreum Sm., a Himalayan plant belonging to the family Ericaceae, has attracted scientific interest because of its rich phytochemical composition and reported pharmacological properties.Objective: The present study aimed to evaluate the preliminary in-vitro anthelmintic activity of the ethanolic flower extract of Rhododendron arboreum against adult earthworms (Eisenia fetida), using albendazole as the reference drug.Materials and Methods: Flowers of R. arboreum were collected from Almora district, Uttarakhand, India, during March 2025 and authenticated by Dr. Y.S. Parmar University of Horticulture and Forestry, Nauni, Solan, Himachal Pradesh, under reference number UHF/FP/HERBARIUM/2026/1827. The dried flowers were powdered and extracted using ethanol using soxhlet apparatus. The anthelmintic activity was evaluated against adult E. fetida. Paralysis time and death time were recorded following exposure to the extract. Albendazole at 20 mg/mL was used as the reference drug, while distilled water served as the negative control.Results: The ethanolic extract exhibited a concentration-related reduction in the reported paralysis and death times. At 20 mg/mL, the paralysis and death times were 37 ± 0.64 and 46 ± 0.44 minutes, respectively. At 40 mg/mL, these values decreased to 32 ± 0.46 and 37 ± 0.19 minutes, respectively. At 60 mg/mL, the corresponding values were 21 ± 0.54 and 31 ± 0.38 minutes. Albendazole produced paralysis and death times of 15 ± 0.90 and 27 ± 0.56 minutes, respectively. Thus, the shortest observed paralysis and death times among the extract-treated groups occurred at 60 mg/mL, although albendazole produced shorter times than the extract.Conclusion: The ethanolic flower extract of R. arboreum demonstrated preliminary activity against E. fetida under the experimental conditions. The observed concentration-related reduction in paralysis and death times warrants further investigation. However, additional experiments, statistical verification, safety evaluation, and testing against relevant parasitic helminths are necessary to establish its potential anthelmintic efficacy.