Sperm antimotility properties of a seed extract of Abrus precatorius.

This study examined the inhibitory effects of a methanol extract of Abrus precatorius seeds on the motility of washed human spermatozoa. The extract caused a concentration-related impairment of percentage sperm motility; with the EC50 concentration being 2.29 mg/ml. This effect on motility was essentially irreversible. With the highest concentration tested (20.0 mg/ml), the onset of the antimotility action was almost immediate. In addition, this concentration impaired the functional integrity of the plasma membrane (hypoosmotic swelling test) and viability (nigrosin-eosin stain) of spermatozoa. In contrast, with a lower concentration (5.0 mg/ml), such effects were not evident. It is concluded that at the lower concentrations the antimotility action may result from a rise in intracellular calcium (not via influx) and/or a decline in cAMP content and/or enhanced generation of a reactive oxygen species.