Also known as bitter apple, Citrullus colocynthis is a Mediterranean plant
used in the past to prevent the implantation of embryos. In addition to causing infertility, the saponins found in this plant can cause serious hepato-renal damage in mice, such as necrosis of liver cells and renal tubules, according to a study published in the "Iranian Journal of Veterinary Research" in 2008. Tetrapleura tetraptera, a plant native to Western Africa and part of the pea family, also contains saponins that are linked to infertility in mice.
Yuan Zhi (Polygala tenuifolia), a plant used in Chinese traditional medicine as an expectorant, contains saponins called polygalasaponins, which show anti-amnesic activity, but high toxicity in most animals, causing nose bleeding and gastrointestinal problems. A study published in January 2011 in the journal "Evidence-Based Complementary and Alternative Medicine" shows that the polygalasaponins toxicity is attenuated when undergoing the chemical reaction of hydrolysis. Therefore, hydrolysate of polygalasaponins (HPS) showed less toxicity in mice. These saponins are linked to an improvement of cognitive ability of mice tested in the Morris water maze, which is a scientific apparatus common in animal behavior laboratories.
Saponins found in red ginseng (Alpinia purpurata) showed anti-tumor properties in mice. According to a Hokkaido University study published in the "Biological and Pharmaceutical Bulletin," the saponins ginsenoside-Rb2, 20(R) and 20(S)-ginsenoside-Rg3 inhibit the lung metastasis of tumor cells in mice. The ornamental plant baby's breath (Gypsophila paniculata) contains a mixture of saponins called Saponinum album. These saponins also showed anti-tumor properties when injected in mice.
Diets rich in saponins can cause weight loss and diarrhea in mice, according to a Wright State University study published in the "Biochemical Systematics and Ecology." Radix platycodi is the root of the balloon flower plant (Platycodon grandiflorum). Rich in saponins, radix platycodi can decrease the level of fat absorption in the intestine of mice, thus reducing body fat, as well as the levels of the fatty substance triacylglycerol in the bloodstream.