Sperm aggregation by water extracts from two Bursera species

Some plants have more than the common utility value, as is the case of some members of the Bursera species such as the Mexican copal, a plant used for worship. Water extracts of several plants have vaginal contraceptive properties. The authors evaluated the sperm agglutinating activity of two Bursera species on human and boar sperm. Extracts from stems and leaves were obtained. Capacitated sperm samples were used in all cases. There were different agglutinating capacities, which were not observed in the vehicle-only samples. The most frequent sperm agglutination response was that involving the heads. Agglutinating activity was higher from stem- than leaf-derived extracts. The results indicate that proteins present in the extracts are responsible for the aggregation of sperm heads.