High temperature effects on flavones accumulation and antioxidant system in Scutellaria baicalensis Georgi cells

Abstract

Scutellaria baicalensis is a traditional Chinese medicinal plant that has long been grown in Hubei Province. However, increasing average annual temperatures in the region have made plants unsuitable for medicinal use. Two flavones, baicalin and baicalein, are the major active ingredients of S. baicalensis. We demonstrated that protracted heat treatment inhibited the accumulation of baicalin and baicalein as well as the activity of phenylalanine ammonla-lyase (PAL). PAL is involved in the phenylpropanoid pathway, which produces baicalin in the plant. Heat treatment also affected the activities of the antioxidant enzymes such as catalase (CAT), superoxide dimutase (SOD) and peroxidase (POD). However, superoxide radical and hydrogen peroxide content of the cells were not significantly impacted by heat treatment. Cells continued growing during the protracted heat stress. Hence, the increasing temperatures in Hubei Province will very likely make S. baicalensis unsuitable for medical use by decreasing the flavonoid content.

Key words: Scutellaria baicalensis Georgi, heat, antioxidant system, flavonoid.