Antifungal and antibacterial metabolites from a French poplar type propolis.

During this study, the in vitro antifungal and antibacterial activities of different extracts (aqueous and organic) obtained from a French propolis batch were evaluated. Antifungal activity was evaluated by broth microdilution on three pathogenic strains: Candida albicans, C. glabrata, and Aspergillus fumigatus. Antibacterial activity was assayed using agar dilution method on 36 Gram-negative and Gram-positive strains including Staphylococcus aureus. Organic extracts showed a significant antifungal activity against C. albicans and C. glabrata (MIC80 between 16 and 31 µg/mL) but only a weak activity towards A. fumigatus (MIC80 = 250 µg/mL). DCM based extracts exhibited a selective Gram-positive antibacterial activity, especially against S. aureus (SA) and several of its methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) strains (MIC100 30-97 µg/mL). A new and active derivative of catechin was also identified whereas a synergistic antimicrobial effect was noticed during this study.

Chemical composition, antioxidant and anti-AGEs activities of a French poplar type propolis.

Accumulation in tissues and serum of advanced glycation end-products (AGEs) plays an important role in pathologies such as Alzheimer's disease or, in the event of complications of diabetes, atherosclerosis or renal failure. Therefore, there is a potential therapeutic interest in compounds able to lower intra and extracellular levels of AGEs. Among them, natural antioxidants (AO) with true anti-AGEs capabilities would represent good candidates for development. The purpose of this study was to evaluate the AO and anti-AGEs potential of a propolis batch and then to identify the main compounds responsible for these effects. In vivo, protein glycation and oxidative stress are closely related. Thus, AO and antiglycation activities were evaluated using both DPPH and ORAC assays, respectively, as well as a newly developed automated anti-AGEs test. Several propolis extracts exhibited very good AO and anti-AGEs activities, and a bioguided fractionation allowed us to identify pinobanksin-3-acetate as the most active component.