Effect of Addition Saccharomyces cerevisiae Elicitor on Total Flavonoid Content and Antioxidant Activity of Gardenia jasminoides Cell Suspension Culture

G. jasminoides is a medicinal plant with diverse properties due to the various secondary metabolites including flavonoids. Flavonoid content in gardenia leaves can be increased through in vitro culture methods, such as CSC combined with elicitation. This process is carried out by adding an elicitor, which provides a stress condition in the culture to produce secondary metabolites. An example of an elicitor capable of increasing secondary metabolites is S. cerevisiae powder. Therefore, this study aimed to examine the morphology of gardenia leaves callus, measure the growth of CSC, determine the optimum elicitation time, and evaluate the most potent concentration of S. cerevisiae powder. The treatments carried out include variations in elicitation duration of 0, 2, 4, and 6 days as well as S. cerevisiae elicitor concentrations of 0, 2.5, 5, and 7.5%. The results showed that the callus of gardenia leaves was friable and yellowish. Gardenia CSC showed two growth phases, namely exponential and stationary. The optimal elicitation period for maximizing total flavonoid content was six days, whereas the ideal period for achieving the highest antioxidant activity was two days. The highest levels of both flavonoids and antioxidant activity were observed with a 7.5% concentration of S. cerevisiae.