Effect of Elicitors on Metabolite Production in Didymella sinensis, an Endophytic Fungus Isolated from C. sinensis

Abstract

Catechins are a type of polyphenolic compounds with strong antioxidant properties, primarily found in the leaves of Camellia sinensis (tea plant) and widely recognised for their therapeutic effects, such as anti-inflammatory, anticancer, anti-tumour, and antimicrobial properties. Additionally, certain endophytic fungi isolated from tea have been identified as capable of producing catechins. However, yield was found to be very low, which poses challenges for practical applications. This study aims to boost catechin production in the endophytic fungus Didymella sinensis (CSPL5b), isolated from C. sinensis, by using the elicitation technique to enhance the biosynthesis of secondary metabolites. This study explores how adding certain substances known as “elicitors” influences catechin production in CSPL5b. The fungal cultures were treated with three different elicitors: Salicylic acid (SA), tea leaf extract (TE), and catechin (CAT) at different concentrations. After 10 and 15days, metabolites were extracted using ethyl acetate to obtain crude extracts. The extracts were then tested for different phytochemical analyses using TLC, and their total phenolic content (TPC) and total flavonoid content (TFC) were measured. Additionally, the DPPH method was used to assess antioxidant ability. Further, quantitative analysis was also done using High Performance Liquid Chromatography (HPLC). Among the elicitors, salicylic acid and catechins significantly enhanced catechin production and bioactivity. This research demonstrates that using elicitation is an effective method for boosting catechin production in D. sinensis. Using fungi as a source of catechins offers a sustainable and reliable alternative to tea plants, making it a cost-effective, eco-friendly, and consistent method for obtaining valuable secondary metabolites.