Three diterpenes from Leonurus japonicus houtt protect primary cultured rat cortical cells from glutamate‐induced toxicity

Abstract

To examine the cytoprotective effects of Leonurus japonicus Houtt, its protection against the glutamate-induced toxicity in primary cortical cultured neurons was tested. In order to clarify the cytoprotective mechanism(s) of this observed effect, isolation was performed to seek and identify active fractions and components. By such fractionation, three known diterpenes--prehispanolone (1), leojaponin (2) and iso-preleoheterin (3)--were isolated from the methanol extracts from the air-dried L. japonicus. Among these three compounds, leojaponin (2) exhibited significant cytoprotective activities against glutamate-induced toxicity, exhibiting cell viability of about 50%, at concentrations ranging from 0.1 microm to 10 microm. Therefore, the cytoprotective effect of L. japonicus might be due to the inhibition of glutamate-induced toxicity by the diterpenes it contains.

GABAA Receptor Binding Assays of Standardized Leonurus cardiaca and Leonurus japonicus Extracts as Well as Their Isolated Constituents

“…Neuroprotective effects have been reported for leonurine [15], a typical guanidine derivative of L. japonicus that was, however, proven to be absent from L. cardiaca in a recent HPLC study [16], contrary to a series of claims [2]. In vitro research on L. japonicus has found a neuroprotective effect against glutamate-induced toxicity in primary cultures of fetal rat neurons, discussing several labdane diterpenes as the most likely contributors to this activity [17]. As a reference compound for our study, the related isoleosibirin, detected in L. japonicus as well as in L. cardiaca [18], was used.…”

Steroids from the aerial parts of Leonurus japonicus

“…(Lamiaceae) have been used for centuries as a common traditional Chinese medicine (Liu et al, 2012). Previous investigations on L. japonicus have led to the isolation of many terpenoids and aromatic compounds (Li et al, 2012;Moon, 2010;Romero-González et al, 2006;Seo et al, 2010;Xiong et al, 2015;Zhou et al, 2013). However, only a few steroids have been reported from the genus Leonurus before (Giang et al, 2005;Ye et al, 2014).…”

Two new diterpenoids from Leonurus japonicus

“…The dried herb is used in TCM for the treatment of various diseases, such as menstrual disturbances, dysmenorrhea, and amenorrhea (Liu et al, 2014). Recently, phytochemical studies on this plant have been reported (Romero-González et al, 2006;Ye et al, 2014;Fuchino et al, 2013;Chang et al, 2010;Moon, 2010;Xiong et al, 2013a,b;Zhang et al, 2013;Peng et al, 2013). Our previous investigation on two plants of the family of Lamiaceae resulted in the isolation of a number of new labdane diterpenes (Wu et al, 2011.…”