Preliminary evaluation of the anti-Candida antibiofilm and phytochemical potential of Graphis ceylanica Zahlbr

Graphis ceylanica Zahlbr., a script lichen, was screened for its antioxidant, TLC profile and antibiofilm potentials. The methanol fraction (MF) and hexane fraction (HF) from an acetone extract were screened for DPPH scavenging, phosphomolybdate total antioxidant capacity (TAC), total phenolic content (TPC), and total flavonoid content (TFC), along with antibiofilm assays against Candida albicans and C. tropicalis . MF displayed higher antioxidant activity than HF, with TAC (A695 = 1.382 ± 0.02), TPC (= 87.81 ± 1.5 mg GAE/g), and TFC (= 5.63 ± 0.29 mg QE/g), thus confirming phenolic enrichment of the methanol fractions reported in other Graphis species. TLC profiling revealed multiple UV-active bands consistent with depsides, depsidones, and aromatic metabolites characteristic of Graphidaceae. Both fractions exhibited promising DPPH scavenging activity, with 46.51% for MF and 40.47% for HF. Most importantly, strong antibiofilm effects against both Candida strains were evident, with HF at 3–5 mg mL ^− 1 and MF at 50–100 mg mL ^− 1 , inhibiting > 75–95% of biofilm formation. Therefore, the current study highlights G. ceylanica as a chemically diverse and bioactive lichen, presenting the first baseline evidence of its antioxidant and antibiofilm properties.