Sapindus

Not to be confused with Soapnet.

Sapindus is a genus of about thirteen species of shrubs and small trees in the lychee family, Sapindaceae and tribe Sapindeae. It is native to warm temperate to tropical regions of the world. The genus includes both deciduous and evergreen species. Members of the genus are commonly known as soapberries^[3] or soapnuts because the fruit pulp is used to make soap. The generic name is derived from the Latin words sapo, meaning "soap", and indicus, meaning "of India".^[4]

Sapindus
Sapindus marginatus shrubs
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Rosids
Order:	Sapindales
Family:	Sapindaceae
Tribe:	Sapindeae
Genus:	Sapindus L.
Type species
Sapindus saponaria L.[1]
Species
See text
Synonyms
Dittelasma Hook.f.[2]

The leaves are alternate, 15–40 cm (5.9–15.7 in) long, pinnate (except in S. oahuensis, which has simple leaves), with 14-30 leaflets, the terminal leaflet often absent. The flowers form in large panicles, each flower small, creamy white. The fruit is a small leathery-skinned drupe 1–2 cm (0.39–0.79 in) in diameter, yellow ripening blackish, containing one to three seeds. Fossils date back to the Cretaceous.^[5][6]

Uses

Soapnut is used with natural dyes to color the yarn of Tasar silk.

Sapindus emarginatus leaves, India

The drupes (soapnuts) contain saponins, which have surfactant properties, being used for washing by ancient Asian and American peoples.^[7][8] A number of other uses for Sapindus have also been reported such as making arrows from the wood and decorative objects from the seeds.^[9]

Folk medicine

Leaf and fruit extracts of Sapindus have historically been used in folk remedies to treat various conditions.^[10]

Insecticide

Sapindus species are used as food plants by the larvae of some Lepidoptera (moths and butterflies) species including Endoclita malabaricus. Kernel extracts of soapnut disrupt the activity of enzymes of larvae and pupae and inhibit the growth of the mosquito Aedes aegypti, an important vector of viral diseases.^[11]

Dyeing process

Soapnut is used as a scouring agent for preparation of coloring fibers such as the yarn of Tussar silk and cotton.^[12]

Species

Sapindus emarginatus drupes in Hyderabad, India

Sapindus drummondii, the Western Soapberry: drupes

The number of species is disputed between different authors, particularly in North America where between one and three species are accepted. As of February 2024^[update], Plants of the World Online includes:^[13]

1. Sapindus chrysotrichus Gagnep. (southern Vietnam)
2. Sapindus delavayi (Franch.) Radlk. (China, India)
3. Sapindus drummondii Hook. & Arn. (USA: Arizona to SE. Colorado and Louisiana)
4. Sapindus emarginatus Vahl (Southern Asia)
5. Sapindus lippoldii I.M.Turner (Cuba)
6. Sapindus mukorossi Gaertn. – Indian Soapberry (India and the Himalayas east to Indochina and Japan)
7. Sapindus oahuensis Hillebr. ex Radlk. – Lonomea (Kauaʻi and Oʻahu, Hawaii)
8. Sapindus rarak DC. (Southeast Asia)
9. Sapindus saponaria L. - 4 subspecies, previously considered as 2:
   1. "S. s. var. drummondii" (Hook. & Arn.) L.D.Benson – Western Soapberry (southwestern US, Mexico) is S. drummondii
   2. S. s. var. saponaria – Wingleaf Soapberry (southeastern US, Caribbean, island of Hawaiʻi, Central, South America);
      Sapindus marginatus Willd. – Florida Soapberry - included here.
10. Sapindus sonlaensis H.M.Tam, N.K.Khoi, N.T.Cuong & T.B.Tran (Sơn La, NW Vietnam)
11. Sapindus tomentosus Kurz - China
12. Sapindus trifoliatus L. – South India Soapnut or Three-leaf Soapberry: Southern India, Pakistan (synonym S. laurifolius Vahl = "Ritha")
13. Sapindus vitiensis A.Gray (American Samoa, Samoa, Fiji)^[3][14][15]

Formerly placed here

• Lepisanthes fruticosa (Roxb.) Leenh. (as S. fruticosus Roxb.)
• Lepisanthes senegalensis (Juss. ex Poir.) Leenh. (as S. senegalensis Juss. ex Poir.)
• Lepisanthes tetraphylla (Vahl) Radlk. (as S. tetraphylla Vahl)
• Talisia cerasina (Benth.) Radlk. (as S. cerasinus Benth.)
• Talisia esculenta (A.St.-Hil.) Radlk. (as S. esculenta A.St.-Hil.)^[15]