Hedyotis

Hedyotis (starviolet)[1] is a genus of flowering plants in the family Rubiaceae. Many species of this genus such as Hedyotis biflora, H. corymbosa and H. diffusa are well known medicinal plants. Hedyotis is native to tropical and subtropical Asia and to islands of the northwest Pacific.[2] It comprises about 115 species.[3] The type species for the genus is Hedyotis fruticosa.[4]

Hedyotis was named by Carl Linnaeus in 1753 in Species Plantarum.[5] This generic name is derived from two Greek words, hedys, “sweet”, and otos, “ear”, in reference to the sweet-scented, ear-shaped leaves of some species.[6]

Hedyotis was formerly defined very broadly by some authors, and included species now placed in Oldenlandia, Oldenlandiopsis, Houstonia, Kadua, and other genera. It is now circumscribed more narrowly, as a monophyletic group that is closely related to Agathisanthemum.[7]

Species include:

Hedyotis lawsoniae
Hedyotis lessertiana
Hedyotis purpurea
Hedyotis verticillaris

In traditional medicine, over 20 Hedyotis species have been used for treatment of diseases and in healing practices. The most popular among these are Hedyotis diffusa and Hedyotis corymbosa which are active principles in several Chinese remedies such as bai hua she she cao, peh hue juwa chi cao and feibao syrup. They are taken for treatment of cancers, infections and other diseases. Phytochemical investigation of Hedyotis species was first published in 1933 upon examining the active components of the medicinal plant H. auricularia.[8] Since then, over 50 novel compounds have been isolated from various member of the genus Hedyotis. These compounds have highly divergent structures including alkaloids, anthraquinones, flavonoids, iridoids, triterpenoids, sterols, lignans and a number of other compounds.[8]