Simultaneous Quantification of Four Marker Compounds in Bauhinia coccinea Extract and Their Potential Inhibitory Effects on Alzheimer's Disease Biomarkers.

Bauhinia coccinea is a tropical woody plant widely distributed in Vietnam and Unnan in southern China. Although many studies have shown the biological activities of extracts from various other species in the genus, no studies have investigated the effects of B. coccinea extracts on biological systems. In the present study, a quantitative analysis of four marker compounds of ethanol extracts of B. coccinea branches (EEBC) was performed using the high performance liquid chromatography (HPLC)-photodiode array (PDA) method. Among gallic acid, (+)-catechin, ellagic acid, and quercitrin contained in EEBC, the most abundant compound was (+)-catechin (18.736 mg/g). In addition, we investigated the EEBC on neuroprotection, antioxidation, and Alzheimer's disease (AD) marker molecules, acetylcholinesterase (AChE), and amyloid-ß (Aß). EEBC significantly inhibited hydrogen peroxide (H2O2)-induced cell death in a HT22 neuronal cell line and increased 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl scavenging activity markedly. EEBC also inhibited AChE and Aß aggregation. Among the four compounds, gallic acid exhibited strong inhibitory effects against AChE activation. In the Aß aggregation assay, the four marker compounds exhibited inhibitory effects lower than 30%. According to the results, EEBC could exert anti-AChE activation and Aß aggregation activities based on the interactive effects of the marker compounds. Our findings suggest that EEBC are sources of therapeutic candidates for application in the development of AD medication based on AChE and Aß dual targeting.