Study on degradation kinetics of magnolol and honokiol in the ethanol extraction of magnolia rostrata

Objective To study degradation law of magnolol and honokiol in the ethanol extraction of magnolia rostrata during storage,concentrating and drying. Methods To find the law of degradation,the contents of magnolol and honokiol were tested by high performance liquid chromatography under storage,concentrating and drying conditions. Results The content of magnolol and honokiol in the ethanolextraction remained almost the same within 20 days when kept indoors. The degradation reactions of magnolol and honokiol were zero-order when concentrating at 60℃ and drying. When drying at 100℃,the rate of degradation was faster. Conclusion Magnolol and honokiol in the ethanol extraction are almost stable within 20 days when kept indoors,but can not be dried and concentrated longer under higher temperature.The rate of degradation is faster when drying at 100℃. In order to ensure the preparation quality,higher temperature and longer time should be avoided during drying and concentrating for the ethanol extraction of magnolia rostrata.