PHENOLIC COMPOSITION, ANTI-BIOFILM, ANTI-QUORUM SENSING, ANTIOXIDANT AND ENZYME INHIBITORY ACTIVITIES OF PTELEOPSIS SUBEROSA (COMBRETACEAE) LEAVES

Abstract

P. suberosa is a multipurpose medicinal plant in West and Central Africa. Fourteen phenolic compounds were identified in the P. suberosa leaves extract using HPLC-DAD and gallic acid (175.10±0.42 μg/g) was the most abundant. The total phenolic content was 112.16 ± 0.33 mg GAE/g DW while the total flavonoid content was 36.10±0.58 mg QE/g DW. Minimal inhibitory concentration (MIC) values for antimicrobial activity were 0.3125 mg/mL and 1.25 mg/mL on S. aureus and E. faecalis respectively and 2.5 mg/mL and 0.3125 mg/mL on E. coli and S. typhi respectively. Biofilm inhibition evaluated at sub-MIC concentrations revealed that gram-negative biofilms were more susceptible to P. suberosa extract than gram-positive ones and E. coli biofilms were the most susceptible. The extract inhibited violacein production and quorum sensing with inhibition zones varying from 17.0±0.5 mm at MIC to 12.0±0.1 mm at MIC/4. The extract showed good antioxidant capacity and was more active in the DPPH• assay than the two standards α-tocopherol and BHA used. In the ABTS•+ and CUPRAC assays, the activity of the extract was greater than that of α-Tocopherol and very close to that of BHA. The extract showed potential to alleviate Alzheimer’s disease by inhibiting acetylcholinesterase and butyrylcholinesterase as well as antidiabetic activity by inhibiting α-amylase and α-glucosidase.