For thousands of years humans have been using a vast array of strange folk contraceptive methods. A team at UC Berkeley recently examined two commonly used traditional plant-based folk remedies and discovered a potentially new mechanism that could lead to non-toxic, non-hormonal contraceptives.
The UC Berkeley team's primary focus of study is in reproduction, with a particular interest in the hormones that trigger hyperactivity in sperm. After looking through some books on contraceptives used by different cultures around the world, the team noted two particular folk remedies that contained non-steroid chemicals that resembled the steroids they knew blocked sperm activity.
The two natural compounds they identified were pristimerin, which is found in a plant known as "thunder god vine" and lupeol, found in plants such as aloe vera, dandelion root and mango. Both of these compounds were shown to block progesterone binding to a protein called ABHD2. The ABHD2 protein is key to releasing a calcium channel that triggers tail whipping strength within individual sperm. When that particular protein is blocked the sperm's stroke is weakened to the point it is unable to penetrate the egg.
As sperm takes up to six hours to mature after entering the female reproductive system, this discovery could help scientists develop either an emergency contraceptive taken before or after intercourse, or a permanent contraceptive that delivers the chemical compound via a skin patch.
"Because these two plant compounds block fertilization 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,'" explained Polina Lishko, assistant professor of molecular and cell biology.
The team hope to expand their research and begin studies on whether the compounds function the same way in primates.
Another incidental discovery from the team's research was that high levels of testosterone and cortisol in a woman's body also blocked the ABHD2 protein. This led the researcher's to conclude that increased stress, and high testosterone, would decrease a woman's fertility by making it harder for sperm to break through an egg's vestment and fertilize it.
Source: UC Berkeley