National Institutes of Health (NIH) states biofilms may be responsible for 65% of microbial infections in humans, including in over 80% of chronic microbial infections (Jamal et al., 2018). Biofilm-related diseases include pneumonia in cystic fibrosis, periodontitis, rhinosinusitis, chronic otitis media, recurrent urinary tract infections, osteomyelitis, non-healing chronic wounds, and prosthesis and implantable device-related infections, among many others (Schulze et al., 2021). Biofilm formation results in increased resistance to both host defences and antimicrobial agents (Singh et al., 2017) – both phenotypes may have quorum sensing (QS) as an underlying molecular mechanism. (Preda & Săndulescu, 2019). Due to the prominent points of biofilms implicated in infectious disease and the spread of antimicrobial resistance (AMR), it is urgent to discover new antimicrobial agents that can regulate biofilm formation and development (Uruén et al., 2020; Vestby et al., 2020).
Plants are rich in diverse bioactive compounds and are likely to hold at least part of the answer to the ever-increasing problem of AMR (Anand et al., 2019). In the last two decades novel antibiofilm and quorum sensing inhibition (QSI) approaches have been extensively developed and reported, including natural products from plants (Lu et al., 2019, 2022). There is evidence that whole plant extracts can have stronger biological effects than individual isolated phytocompounds (Furner-Pardoe et al., 2020), so the overall aim of this review is to summarise antibiofilm whole plant extracts, and their known mechanisms in biofilm formation and QS. According to the review findings, the majority of the antibiofilm whole plant extracts showed promising preclinical data for antibiofilm efficiency in numerous bacterial and fungal species. Potential regulatory mechanisms included inhibition of biofilm formation via decreasing cell hydrophobicity, or reducing adhesins; reducing matrix formation; or via QSI by reducing QS gene expression, inhibiting QS receptors, or AHL interference (quorum quenching). These antibiofilm whole plant extracts are promising candidates which could provide novel strategies for biofilm-associated infections.