Antibacterial, antibiofilm and antibiotic-potentiating effects of a polyphenol-rich fraction of Dicranopteris linearis (Burm.f.) Underw.

Abstract

Dicranopteris linearis is a fern used traditionally for various skin disorders. However, scant studies are available to support its use. The present study evaluates the potential of a standardized polyphenol-rich fraction of D. linearis in counteracting planktonic and biofilm bacteria that affects skin wounds, by itself, and in combination with conventional antibiotics. MIC was evaluated using the broth microdilution method, followed by inoculation onto agar medium to determine its MBC. Time-kill study was conducted by viable cell count method and morphological changes of bacteria were evaluated by SEM. Bacterial biofilm prevention and eradication was evaluated by crystal-violet staining and MTT assay. D. linearis fraction demonstrated dose dependent antibacterial effect on S. aureus and P. aeruginosa. Both bacteria were observed to undergo morphological changes upon treatment. The fraction synergized with penicillin G, ampicillin and chloramphenicol to significantly inhibit the growth of S. aureus and MRSA. Its combination with vancomycin also reduced the dose required by the antibiotic to prevent biofilm formation. The present findings support the traditional use of D. linearis for skin disorder due to bacterial infection and may be further explored as an adjunct to conventional antibiotics for managing infectious wounds.