Oenothein B, a Bioactive Ellagitannin, Activates the Extracellular Signal-Regulated Kinase 2 Signaling Pathway in the Mouse Brain.

Satoshi Okuyama,Morio Yoshimura,Takashi Yoshida,Yoshiaki Amakura,Yoshiko Furukawa,Mitsunari Nakajima

doi:10.3390/plants10051030

Satoshi Okuyama, Morio Yoshimura + Show 4 more

Open Access

https://doi.org/10.3390/plants10051030

Copy DOI

Abstract

(1) Background: Oenothein B, a cyclic dimeric ellagitannin present in various medicinal plants, has been reported to exert diverse effects that are beneficial for the treatment and prevention of diseases, including cancer and infections. We recently showed that oenothein B also functions in the brain because its oral administration to systemic inflammatory model mice reduced inflammatory responses in the brain and suppressed abnormal behavior. (2) Results: The present in vivo results demonstrated that oenothein B activated extracellular signal-regulated kinase 2 and cAMP response element-binding protein in the brain, both of which play important roles in synaptic transmission and learning/memory in the central nervous system (CNS). (3) Conclusions: These results suggest that oenothein B exerts neuroprotective effects on the CNS by not only its anti-inflammatory activity but also by enhancing neuronal signaling pathways.

Highlights

Published: 20 May 2021Oenothein B, which has a unique macrocyclic structure (Figure 1), was initially isolated from the leaves of Oenothera erythrosepala (Oenotheraceae) in 1990 [1] and was subsequently found to be widely distributed in various medicinal plants of Myrtaceae and Lythraceae other than Oenotheraceae [2]
The present results demonstrated that the p.o. administration of oenothein B activated ERK2 in the healthy mouse brain (Figure 2)
Hydrophilic oenothein B may not have been able to pass through the blood–brain barrier (BBB) under the present experimental conditions

Summary

Introduction

Published: 20 May 2021Oenothein B, which has a unique macrocyclic structure (Figure 1), was initially isolated from the leaves of Oenothera erythrosepala (Oenotheraceae) in 1990 [1] and was subsequently found to be widely distributed in various medicinal plants of Myrtaceae and Lythraceae other than Oenotheraceae [2]. Oenothein B-rich plant materials, such as willow herb tea (hot extracts from the leaves and flowers of Epilobium species of Oenotheraceae), are capable alternatives for use as pharmaceuticals to reduce the risk of diseases closely associated with active oxygen damage [4,5] These biological effects have been proven using peripheral cells/tissues [2,3], and our in vivo findings showed that oenothein B functioned in the brain: (1) its per os (p.o.) administration reduced neuroinflammation in the brain during systemic inflammation induced by lipopolysaccharide (LPS; an inflammatory agent) and (2) neuroinflammation-induced abnormal behavior was suppressed in these mice [6].

Methods

Results

Conclusion