Study of Ethyl Acetate Crude Extract of Lasiodiplodia pseudotheobromae IBRL OS-64, an Endophytic Fungus Isolated from the Leaf of Ocimum sanctum for Anti-Biofilm Agent (Funded Work)

Abstract

The capability of bacteria such as Streptococcus mutans to form biofilm leads to increased resistance to some conventional antimicrobial substances, indicating a need for alternative antibiotics. Therefore, the present study was carried out to investigate the anti-biofilm activity of ethyl acetate crude extract of endophytic fungus, Lasiodiplodia pseudotheobromae IBRL OS-64, isolated from the leaf of Ocimum sanctum against S.mutans. The Congo red agar and semi-quantitative adherence assays were performed to determine biofilm formation and anti-biofilm activity, respectively. Meanwhile, the microscopic analysis was carried out to evaluate the efficacy of the extract in eradicating biofilm formation. The findings revealed that S. mutans is a good biofilm producer by producing black colonies on Congo red agar, an optical density (OD) value of 0.643 on the semi-quantitative adherence assay and the fungal extract possesses anti-biofilm activity by eradicating biofilm formation on the test tube and Congo red agar. Furthermore, the extract demonstrated significant anti-biofilm activity against initial and pre-formed biofilm of S. mutans with the highest percentage of inhibition of 89.23% and 54.14%, respectively. The light microscopy (LM) and scanning electron microscopy (SEM) photomicrographs proved that the fungal extract significantly eliminates the extracellular polysaccharide (EPS) matrices and hinder the attachment of the bacterial cells for biofilm formation. Hence, the data suggest that ethyl acetate crude extract from L. pseudotheobromae IBRL OS-64 may be an effective anti-biofilm agent to eradicate oral cavity bacteria.