Phytochemical Profiling and Spermicidal Activity of Withania somnifera Stem Extract in a Vaginal Gel

Abstract

Plants are a vital natural resource for many countries and have multiple benefits, including providing primary healthcare services to rural populations and serving as a source of various economic products. Withania somnifera (Ashwagandha), belonging to the Solanaceae family, is a widely used medicinal plant known for its diverse pharmacological activities. This herb exhibits antioxidant, anti-inflammatory, adaptogenic, and potential antifertility properties. The aim of the present work was to investigate the sperm immobilization potential of the non-aqueous extract obtained from the stem of Withania somnifera and develop a suitable formulation in the form of a pH-responsive vaginal in-situ gel. The sperm immobilization activity of the extract was evaluated by incubating human sperm with different concentrations of the extract at 37°C for 30 minutes. The percentage of immobilized sperm was determined using microscopy. At a concentration of 0.4 μg/mL, the extract exhibited 100% sperm immobilization activity. This significant reduction in sperm motility and viability may be attributed to the presence of bioactive compounds such as withanolides and alkaloids. The in-situ gel was formulated for localized action using a pH-sensitive system. The prepared formulation transformed from solution to gel at vaginal pH (3.5-4.5). In the gel formulation, Carbopol 940 acted as a pH-sensitive agent, while HPMC K4M contributed to mucoadhesiveness. The formulation was optimized using Design Expert software for parameters including pH, viscosity, and syringeability.