Lichen is a unique symbiotic organism formed from the mutualism relationship between fungus and algae. The aims of this research are to isolate and to examine antifungal activity of secondary metabolite compound from lichen Teloschistes flavicans. This research was conducted by extracting lichen dried powder using acetone solvent for 3×24 hours. The extract was isolated by Column Chromatography (CC) and Thin Layer chromatography (TLC) with G60 silica gel as stationary phase. Then it was eluted by n-hexane and ethyl acetate solvents in a gradient elution. The isolate was obtained and purified by recrystallization process then determined by using UV-VIS, FTIR, LC-MS, and 1H-NMR. The isolated compound is an orange needle "3-[1'-(2",3"-dihydroxy-phenyl)-propyl]-7hydroxy-chroman-4-one" with the formula of C18H18O5. The antifungal activity test against Aspergillus flavus using disc diffusion method showed that the inhibitory zone was 11 mm in the concentration of 1000 mg mL-1 .

Exploration of lichen natural compounds has attracted a lot of attention from researchers as potential medicinal raw materials because chemical compounds contained in lichen have many properties. The potential for developing secondary metabolite compounds of lichen has become a trend for various benefits, for example, in cosmetics, agriculture, health, and food. Lichen Teloschistes flavicans was a concern to study because there were not many reports of secondary metabolites that have antimicrobial activity. The research objective was to examine antimicrobial activity using 3-[1’-(2”,3”-dihydroxy-phenyl)-propyl]-7hydroxy-chroman-4-one compound from lichen Teloschistes flavicans. The antimicrobial activity test was a well diffusion method. Bioactivity was determined by calculating the clear zone formed around the well. Antimicrobial activity testing indicated the inhibition of bacterial growth at a concentration of 500 ppm and 1000 ppm with the respective inhibition zones namely E. coli (10-11 mm), S. Typhi (2-5 mm), K. pneumoniae (11-13 mm), and S. aureus (10-13 mm). Also, B. cereus bacteria and C. albicans fungi were only inhibited at a concentration of 1000 ppm with an inhibition zone of 6 mm each. This research provides scientific knowledge about the potential development of lichen T. Flavicans as an antimicrobial.

Acetone extract of lichen Usnea longissima (Ach.) and its usnic acid constituent (concentrations of 0.1, 0.5; 1.0 and 10.0 mg/mL) was investigated in order to examine the activity of antimicrobial test i.e. Escherichia coli ATCC 35218, Salmonella typhi ATCC 13311, Klebsiella pneumoniae ATCC 70603, Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 14579, Candida albicans, and Aspergillus flavus as pathogenic fungus. The usnic acid constituent was tested by means of extensive Retention factor (Rf) compared with data reported in the literatures. High-inhibitory activity test using acetone extract showed that it can inhibit activity of E.