Abstract
Rehmannia glutinosa is one of the 50 fundamental herbs used in traditional Chinese medicine, where it has the name Sheng Di huang. Rehmannia is used for diabetes, fever, osteoporosis, and allergies; and as a general tonic.
There is not enough information to know how Rehmannia might work in human organism. However, some chemical substances in Rehmannia were studied in vitro and in vivo, so that there is a lot of information on their biological effects.
The main active compound of this plant is considered catalpol. Catalpol is one of the most common iridoids in nature and Rehmannia it contains a large amount.
This iridoid glucoside appears to possess many excellent pharmacological activities. Some results demonstrated that catalpol may be useful for neuroprotection and memory enhancement, and the mechanism may be related to the central cholinergic system activities.