Quantitative Effects of Temperature and Light Intensity on Accumulation of Bioactive Compounds in St. John's Worth

Abstract

The quantitative effects of temperature and light intensity on accumulation of naphthodianthrones and phloroglucinol derivatives were examined on St. John's worth. Plants were grown in greenhouse separated into shaded and un-shaded parts. During the experiment temperature and light intensity were measured daily; plants were harvested weekly and assayed for the chemical analysis by HPLC method. Multi regression analyses were performed to describe the quantitative effects of temperature and light intensity on accumulation of analyzed compounds. The results show that the increase in temperature from 24 to 32°C and light intensity from 803.4 to 1618.6 μmol m-2 s -1 determines the continuous increase in content of bioactive compounds. The relationship between temperature, light intensity and accumulation of hyperforine, hypericine and pseudohypericine was expressed by multiple regression models. Our data suggested that temperature and light intensity are important environmental factors in the biotechnological process of raw material production of St. John's worth. The mathematical model produced in the present study could be applied as useful tool for prediction of content of bioactive compounds and standardization of plant material.