Rehmannia

Rehmannia
File:Rehmannia.JPG
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Asterids
Order:	Lamiales
Family:	Orobanchaceae
Genus:	Rehmannia Libosch. ex Fisch. & C.A. Mey.
Species
See text

Rehmannia is a genus of six species of flowering plants in the order Lamiales, endemic to China.

The genus was included in the family Scrophulariaceae or Gesneriaceae in some older classifications. The current placement of the genus is in neither Scrophulariaceae s.s. nor Plantaginaceae s.l. (to which many other former Scrophulariaceae have been transferred). Earlier molecular studies suggested that its closest relatives were the genera Lancea and Mazus (Oxelman et al., 2005), which have been included in Phrymaceae (Beardsley & Olmstead, 2002). Subsequently it was found (Xie et al., 2009) that Rehmannia and Triaenophora are jointly the sister group to Lindenbergia and the parasitic Orobanchaceae.

Uses

Sometimes known as Chinese Foxglove due to its superficial resemblance to the genus Digitalis, the species of Rehmannia are perennial herbs. The plants have large flowers and are grown as ornamental garden plants in Europe and North America, and are used medicinally in Asia.

Known as dìhuáng (地黄) or gān dìhuáng (干地黄) in Chinese, R. glutinosa is used as a medicinal herb for arthritic conditions within Chinese traditional formulations.

Chemical constituents

Rehmannia contains the vitamins A, B, C, and D, as well as other compounds, such as catalpol, an iridoid glycoside, that has been shown to exert protective effects on dopaminergic neurons in aged rats to help inhibit microglial activation, thereby reducing the production of pro-inflammatory factors.

Homonym

The name "Rehmannia" has also been given to a genus of Jurassic ammonites belonging to the family Reineckeidae.

Species

Species include:

• Rehmannia chingii
• Rehmannia elata
• Rehmannia glutinosa - (Gan) Di huang in Chinese (Chinese: (干)地黃)
• Rehmannia henryi
• Rehmannia piasezkii
• Rehmannia solanifolia

External links

• Oxelman, B.; Kornhall, P.; Olmstead, R.G.; Bremer, B. 2005. Further disintegration of the Scrophulariaceae. Taxon 54 (2): 411-425.
• Beardsley, P. M. & Olmstead, R. G. 2002. Redefining Phrymaceae: the placement of Mimulus, tribe Mimuleae, and Phryma.American Journal of Botany 89: 1093-1102 (available online)
• Zhi Xia, Yin-Zheng Wang and James F. Smith 2009. Familial placement and relations of Rehmannia and Triaenophora (Scrophulariaceae s.l.) inferred from five gene regions, American Journal of Botany 96: 519-530(available online).
• Flora of China: Rehmannia