Sapindus is a genus of about five to twelve species of shrubs and small trees in the Sapindaceae, native to warm temperate to tropical regions in both the Eastern and Western Hemispheres. The genus includes both deciduous and evergreen species. Common names include soapberry and soapnut, both names referring to the use of the crushed seeds to make soap.
The leaves are alternate, 15-40 cm long, pinnate, with 14-30 leaflets, the terminal leaflet often absent. The flowers form in large panicles, each flower small, creamy white. The fruit, called a soap nut, is a small leathery-skinned drupe 1-2 cm diameter, yellow ripening blackish, containing one to three seeds.
Soap nuts contain saponin, a natural detergent which is used to clean clothes. Soap nuts have become popular as an environmentally friendly alternative to manufactured, chemical detergents . A few nuts can be placed in a cotton drawstring bag in with a washload and reused several times. Soap nuts are safe for washing silk, woolens and other delicate fabrics.
Soap nuts, especially are used medically as an expectorant, emetic, contraceptive, and for treatment of excessive salivation, epilepsy, chlorosis, and migraines. Studies show that saponin from soap nuts inhibits tumor cell growth. Soap nuts are among the list of herbs and minerals in Ayurveda. They are a popular ingredient in Ayurvedic shampoos and cleansers. They are used in Ayurvedic medicine as a treatment for eczema, psoriasis, and for removing freckles. Soap nuts have gentle insecticidal properties and are traditionally used for removing lice from the scalp.
Soap nuts are antimicrobial and are beneficial for septic systems and greywater. Soap nuts are used in the remediation of contaminated soil. They are used by jewelers, especially in India and Indonesia, to remove the tarnish from silver and other precious metals.
Sapindus species are used as food plants by the larvae of some Lepidoptera (moths and butterflies) species including Endoclita malabaricus.Species The number of species is disputed between different authors, particularly in North America where between one and three species are accepted.