Plant chemicals effective as emergency contraceptive, study suggests

Researchers from the University of California, Berkley, have identified two chemicals found in anti-fertility folk medicines which block fertilisation and may make effective alternatives to current hormone-based contraceptives, which sometimes cause side effects.

The research was inspired by natural contraceptives used by indigenous peoples around the world, including pristimerin, from the plant Tripterygium wilfordii, also known as ‘thunder god vine.’ Leaves from the plant have been used as an antifertility drug in Chinese traditional medicine and has also been used as a folk remedy for rheumatoid arthritis.

Published in the journal Proceedings of the National Academy of Sciences, the study showed the chemicals were effective at low doses that seem to have no adverse effect on egg or sperm, but reduce the sperm’s ability to propel itself forward.

Human sperm take about five to six hours to mature once they enter the female reproductive system, which is enough time for the drug to enter the system and block the kick. The researchers have suggested that the chemicals could serve as an emergency contraceptive taken either before or after intercourse, or as a permanent contraceptive via a skin patch or vaginal ring

Polina Lishko, an assistant professor of molecular and cell biology, who led the team that discovered the anti-fertility properties of the two chemicals, commented: “Because these two plant compounds block fertilisation at very, very low concentrations – about 10 times lower than levels of levonorgestrel in Plan B – they could be a new generation of emergency contraceptive we nicknamed ‘molecular condoms’. If one can use a plant-derived, non-toxic, non-hormonal compound in lesser concentration to prevent fertilisation in the first place, it could potentially be a better option."