Antimicrobial abietane diterpenoids against resistant bacteria and biofilms

Antimicrobial resistance (AMR) is a growing worldwide threat to public health due to the increase of resistant pathogens to the existing antimicrobial therapy. Common and nosocomial infections are beginning to require 2nd and 3rd line antibiotic therapy, increasing time and cost of treatment, and also contributing to the development of multidrug resistance (MDR). Natural products remain an important source of new bioactive compounds and drug prototypes that can lead to new and more effective antimicrobial agents. Abietane diterpenoids display a wide spectrum of biological activities, including antibacterial, antifungal, antiviral and anti-parasitic. These compounds were found to be effective against Mycobacterium tuberculosis and Staphylococcus aureus, including methicillin-resistant (MRSA) strains and biofilm infection of S. aureus. Structure-activity relationship analysis suggests that the antimicrobial activity of abietane diterpenoids is related to some characteristic features of the abietane skeleton and is dependent on the degree of substitution, the nature and position of the substituents, and the overall lipophilicity of the compound.