Rhinacanthin-C but Not -D Extracted from <em>Rhinacanthus nasutus</em> (L.) Kurz Offers Neuroprotection via ERK, CHOP, and LC3B Pathways

Neurodegenerative diseases present an increasing problem as the world’s population ages; thus, the discovery of new drugs that prevent diseases such as Alzheimer’s, and Parkinson’s diseases are vital. In this study, Rhinacanthin-C and -D were isolated from <i>Rhinacanthus nasustus</i>, u...

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Bibliographic Details
Main Authors: Varaporn Rakkhittawattana, Pharkphoom Panichayupakaranant, Mani I. Prasanth, James M. Brimson, Tewin Tencomnao
Format: Article
Language:English
Published: MDPI AG 2022-05-01
Series:Pharmaceuticals
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Online Access:https://www.mdpi.com/1424-8247/15/5/627
Description
Summary:Neurodegenerative diseases present an increasing problem as the world’s population ages; thus, the discovery of new drugs that prevent diseases such as Alzheimer’s, and Parkinson’s diseases are vital. In this study, Rhinacanthin-C and -D were isolated from <i>Rhinacanthus nasustus</i>, using ethyl acetate, followed by chromatography to isolate Rhinacanthin-C and -D. Both compounds were confirmed using NMR and ultra-performance-LCMS. Using glutamate toxicity in HT-22 cells, we measured cell viability and apoptosis, ROS build-up, and investigated signaling pathways. We show that Rhinacanthin-C and 2-hydroxy-1,4-naphthoquinone have neuroprotective effects against glutamate-induced apoptosis in HT-22 cells. Furthermore, we see that Rhinacanthin-C resulted in autophagy inhibition and increased ER stress. In contrast, low concentrations of Rhinacanthin-C and 2-hydroxy-1,4-naphthoquinone prevented ER stress and CHOP expression. All concentrations of Rhinacanthin-C prevented ROS production and ERK1/2 phosphorylation. We conclude that, while autophagy is present in HT-22 cells subjected to glutamate toxicity, its inhibition is not necessary for cryoprotection.
ISSN:1424-8247