Investigation of the Antimicrobial Activity of Blueberry Twig Extract and Its Potential Use in Cosmetic Formulations

Abstract

Topical infections and their difficult treatments are one of the challenges arising from antimicrobial resistance. Herbal formulations are an important resource in drug development for the treatment of infections that cause various health problems. Therefore, this study aimed to determine the antimicrobial and photoprotective potential of blueberry (Vaccinium spp.) twig extract (BTE) as well as formulate a herbal cream for topical treatments. The biological activity of BTE against clinically important strains such as Escherichia coli O157:H7, Staphylococcus aureus ATCC 25923, Bacillus cereus RSKK 863, Candida albicans ATCC 10231 and Candida glabrata RSKK 04019 was evaluated using both disc diffusion and micro-dilution methods. BTE at a concentration of 4 mg/µL produced the highest inhibition zone diameter of 11.01 mm on B. cereus RSKK 863, followed by E. coli O157:H7 with 10.42 mm. The results from micro-dilution methods indicated that the lowest minimum inhibitory concentration (MIC) value (25 µg/µL) was against B. cereus RSKK 863. The protective capacity of BTE against UV-B rays was determined spectrophotometrically. The sun protection factor (SPF) of the extract was calculated as 4.60 and in cream formulations containing 10 mL of this extract, SPF increased to 26.12. Moreover, in cream formulations where BTE was combined with Streptococcus thermophilus MAS-1, a synergistic antimicrobial effect was observed with wider zones of inhibition against all test microorganisms. Based on the results, BTE may be suitable for evaluation as an antimicrobial, antifungal and photoprotective agent in multifunctional topical formulations containing natural ingredients.