Gemmotherapy Extracts Like the Dog Rose, Lingonberry, Sea Buckthorn, Blackthorn, Common Grape, Hawthorn, Raspberry and Boxwood Feature Variable Yet Excelling Antimicrobial Effects.

Background: Antibiotic resistance is spreading, and the effectiveness of the most widely used antibiotics is decreasing. These issues are global health and food safety concerns that require immediate attention. One potential solution is the use of various gemmotherapy extracts (GTEs). However, there is a paucity of studies investigating the presumptive antimicrobial activity of GTEs. Methods: In this comparative study, we are assessing the antimicrobial properties of eight selected GTEs, as well as their polyphenol content and antioxidant activity, against a panel of microorganisms (Gram-positive and Gram-negative bacteria, yeasts, and molds). We are using the agar diffusion method (ADM) and the broth microdilution method (BMD) to determine the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). Results: Among the analyzed extracts, dog rose, lingonberry, sea buckthorn, blackthorn, and common grape GTEs showed the highest total phenolic content, antioxidant activity, and the most relevant antimicrobial activity including certain differences with respect to the microbiostatic and/or microbicidal properties. These results demonstrate the relative strength of the antimicrobial effects of specific GTEs against certain microbial species, which could facilitate the use of these GTEs in personalized and/or specific antimicrobial therapies.