ABSTRACT
Dioscorea polystachya, commonly known as Chinese yam, is a herbaceous perennial vine native to Central and South China, the Kuril Islands and Taiwan. Edible soya, Glycine max, an annual in the Fabaceae family, grows in the Royal College of Physicians’ Garden. Its natural habitat is the open woodland, grassland, scrub and verges of East Asia. Dioscorea contains diosgenin, Agave and Corchorus contain hecogenin, and Glycine max contains stigmasterol. These sterols are extracted from the plant and converted into steroids. There are two groups of steroids that govern aspects of our bodies: corticosteroids which include glucocorticoids like cortisol and mineralocorticoids like aldosterone; and the ‘sex hormones’: oestrogen, progestogens and androgens such as testosterone. Medicinal uses of steroids depend on the availability of plentiful supplies of the pure substances made into appropriate and convenient dosage forms. Derivatives with better therapeutic properties were developed subsequently, such as the fluorocorticoids, and the contraceptive steroids mestranol and norethisterone.
