Determination of antimicrobial and anti-quorum sensing activities of water and ethanol extracts propolis

Citrus Honeys from Three Different Regions of Turkey: HPLC-DAD Profiling and in Vitro Enzyme Inhibition, Antioxidant, Anti-Inflammatory and Antimicrobial Properties with Chemometric Study

The objectives of the present study are to compare the phenolic profiles and biological activities of 15 citrus honey samples from three different locations in Turkey using a chemometric approach. The HPLC-DAD analysis was used to determine phenolic profiles. Nineteen phenolic compounds were identified. Gallic acid (107.14-717.04 μg/g) was recorded as the predominant compound. AF (Antalya-Finike) had the highest antioxidant activity in ABTS⋅+ (IC50 : 18.01±0.69 mg/mL), metal chelating (IC50 : 6.20±0.19 mg/mL) and CUPRAC (A0.50 : 12.05±0.68 mg/mL) assays, while it revealed the best anti-inflammatory activity against COX-2 (17.28±0.22 %) and COX-1 (43.28±0.91 %). AM (Antalya-Manavgat) was the most active in β-carotene-linoleic acid (IC50 : 10.05±0.19 mg/mL), anti-urease (38.90±0.69 %), anti-quorum sensing and antimicrobial activities. AKO1 (Adana-Kozan-1) in DPPH⋅ (IC50 : 34.25±0.81 mg/mL) assay, AKU1 (Antalya-Kumluca-1) in tyrosinase inhibition activity (37.73±0.38 %) assay, AKU2 (Antalya-Kumluca-2) in AChE (10.55±0.63 %) and BChE (9.18±0.45 %) inhibition activity assays showed the best activity. Chemometric tools were applied to the phenolic compositions and biological properties. PCA and HCA ensured that 15 citrus honey samples were grouped into 3 clusters. The results showed that myricetin, kaempferol, vanillin, protocatechuic acid, rosmarinic acid, rutin, vanillic acid, gallic acid, catechin and p-hydroxyphenyl acetic acid are phenolic compounds that can be used in the classification of citrus honeys.

A comparative study of antimicrobial, anti-quorum sensing, anti-biofilm, anti-swarming, and antioxidant activities in flower extracts of pecan (Carya illinoinensis) and chestnut (Castanea sativa)

Antibiotic resistance, which has increased rapidly in recent years because of uncontrolled and unconscious antibiotic consumption, poses a major threat to public health. The inadequacy of existing antibiotics has increased the need for new, effective, and less toxic antibiotic raw materials or antibiotic derivatives. Pecan (Carya illinoinensis) and Chestnut (Castanea sativa) flowers possess abundant pollen contents and exhibit similar morphological features. The purpose of this study was to compare these two flower extracts in terms of their antimicrobial and antioxidant activities. Total phenolic content, total flavonoid contents, and phenolic components were also analyzed in aquatic and ethanolic extracts. Antioxidant activities were measured using ferric reducing/antioxidant capacity (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods. Antimicrobial and antifungal activities were compared by means of agar diffusion tests against bacteria including Staphylococcus aureus, Bacillus cereus, Mycobacterium smegmatis, Acinetobacter haemolyticus, and Chromobacterium violaceum, and the yeasts Candida albicans and Candida parapsilosis. Anti-quorum sensing (anti-QS), anti-biofilm, and anti-swarming (SW) activities were also studied against Chromobacterium violaceum ATCC 31532, Chromobacterium violaceum ATCC 12472, and Pseudomonas aeruginosa PA01, respectively. Both extracts were rich in ellagic acid and gallic acid and exhibited similar antioxidant properties. Both flower extracts exhibited high antimicrobial and antifungal activities as well as anti-biofilm, anti-QS, and anti-SW activities.

Antibiofilm and Anti-Quorum Sensing Potential of Cycloartane-Type Triterpene Acids from Cameroonian Grassland Propolis: Phenolic Profile and Antioxidant Activity of Crude Extract

Propolis is very popular for its beneficial health properties, such as antimicrobial activity and antioxidant effects. It is one of the most long-serving traditional medicines to mankind due to its interesting chemical diversity and therapeutic properties. The detailed chemical information of propolis samples is very necessary to guarantee its safety and for it to be accepted into health care systems. The phenolic profile of the hydroethanolic extract was determined using HPLC-DAD, and the antioxidant was evaluated using five complementary methods. Triterpenoids were isolated using column chromatography and characterized using 1H NMR and 13C NMR. The effects of the extract and the isolated compounds on quorum sensing mediated processes and biofilm formation in bacteria were evaluated. Protocatechic acid (40.76 ± 0.82 µg/g), 4-hydroxybenzoic acid (24.04 ± 0.21 µg/g), vanillic acid (29.90 ± 1.05 µg/g), quercetin (43.53 ± 1.10 µg/g), and luteolin (4.44 ± 0.48 µg/g) were identified and quantified. The extract showed good antioxidant activity in the DPPH•, ABTS•+, CUPRAC, and metal chelating assays, and this antioxidant effect was confirmed by cyclic voltammetry. 27-Hydroxymangiferonic acid (1), Ambolic acid (2), and Mangiferonic acid (3) were isolated from anti-quorum sensing activity at MIC, and it was indicated that the most active sample was the extract with inhibition diameter zone of 18.0 ± 1.0 mm, while compounds 1, 2, and 3 had inhibition zones of 12.0 ± 0.5 mm, 9.0 ± 1.0 mm, and 12.3 ± 1.0 mm, respectively. The samples inhibited the P. aeruginosa PA01 swarming motility at the three tested concentrations (50, 75, and 100 μg/mL) in a dose-dependent manner. The propolis extract was able to inhibit biofilm formation by S. aureus, E. coli, P. aeruginosa, C. albicans, and C. tropicalis at MIC concentration. Compound 1 proved biofilm inhibition on S. aureus, L. monocytogenes, E. faecalis, E. coli, and C. tropicalis at MIC and MIC/2; compound 2 inhibited the formation of biofilm at MIC on S. aureus, E. faecalis, E. coli, S. typhi, C. albicans, and C. tropicalis; and compound 3 inhibited biofilm formation on E. faecalis, E. coli, C. albicans, and C. tropicalis and further biofilm inhibition on E. coli at MIC/4 and MIC/8. The studied propolis sample showed important amounts of cycloartane-type triterpene acids, and this indicates that there can be significant intra-regional variation probably due to specific flora within the vicinity. The results indicate that propolis and its compounds can reduce virulence factors of pathogenic bacteria.