Extraction of Oleanolic Acid from Clematis mandshurica and Protective Effect of the Acid on Neural Function and Early Brain Injury after Subarachnoid Haemorrhage

Abstract

This paper aims to design a simple and rapid way to extract and determination of oleanolic acid from Clematis mandshurica Rupr. (C. mandshurica), and to disclose the protective effect of the acid on neural function and early brain injury after subarachnoid haemorrhage. To this end, an orthogonal test was performed to examine the effects of ultrasonic-assisted extraction (UAE) variables (i.e. liquid-material ration, time, temperature and frequency) on the extraction of oleanolic acid from C. mandshurica. Then, the oleanolic acid from C. mandshurica was quantified and analysed by liquid chromatography with photodiode array detection (LC-DAD), and the fraction of oleanolic acid was collected by automatic fraction collector. Finally, the author investigated how oleanolic acid influences the neural function and early brain injury after subarachnoid haemorrhage. Through the analysis, the highest oleanolic acid yield of 0.7192% was obtained with the extraction temperature of 70°C, extraction frequency of 90kHz, extraction time of 10min and liquid-material ratio of 30:1. Meanwhile, significant improvement of neural function was observed in the oleanolic acid group of 20mg/kg, and the model group suffered from much more serious neural function injuries than the sham-operated group. This means the oleanolic acid group of 20mg/kg can effectively reduce the cerebral vascular permeability caused by subarachnoid haemorrhage. This research reveals the protective mechanism of oleanolic acid on protection against early brain injury after subarachnoid haemorrhage in rats.