Spermicidal activity of I ndian seaweeds: an in vitro study

Summary Contraceptive properties of seaweeds are still stands as lacuna; in this context, the screening of in vitro male contraceptive properties of crude ethanolic extract of I ndian seaweeds against normal human sperm is carried out. In total, twelve seaweeds were screened for in vitro spermicidal activity. Among these twelve seaweeds, H alimeda gracilis showed 100% inhibition of human spermatozoa at 10 mg ml −1 concentration in 20 s and its EC 50 value was 2.05 mg ml −1 in 20 s. Further, dose‐ and time‐dependent spermicidal assay revealed that the sperm was completely immobilised for 20 s. Plasma membrane of sperm was damaged due to the exposure of H . gracilis extract. MTT assay with H . gracilis extract showed 88.5% of cytotoxic incidence. H . gracilis extract tested for cytotoxicity against A rtemia salina recorded LC 50 value of 34.8 μg ml −1 . Phytochemical analysis of H . gracilis extract evidenced the presence of alkaloids, flavonoids, proteins and sugars. Results of this study clearly inferred that the synergistic effect of active principles reside within the H . gracilis extract had shown better contraceptive activity.