Anticholinesterase, anti-alpha-glucosidase, antioxidant and antimicrobial effects of four Algerian propolis

This study aimed to investigate the functional properties of four Algerian propolis collected from El-Menia, Oum el Bouaghi, El Harrouch and Collo regions. The total bioactive content, antioxidant, anti-enzymatic and antimicrobial effects of the four propolis methanolic extracts were evaluated using in vitro assays. The highest amount of total phenolic (561.99 +/- 3.50 mu g GAE/mg E) and flavonoid content (76.98 +/- 0.26 mu g QE/mg E) was found in propolis from El-Menia. Antioxidant tests (DPPH, ABTS, CUPRAC and ferric reducing power) revealed the strong scavenging and reducing abilities of the extracts. Anti-enzymatic assays against acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and alpha-glucosidase showed that all extracts possessed a potent inhibitory effect on alpha-glucosidase better than acarbose and revealed the ability of extracts to inhibit BChE more effectively than AChE. However, the extract of propolis from El Menia was the best inhibitor of the three key enzymes with IC50 values of 11.40 +/- 0.58 mu g/mL 16.06 +/- 0.85 mu g/mL and 71.29 +/- 2.73 mu g/mL against alpha-glucosidase, BChE and AChE, respectively. The antimicrobial assay indicated that all extracts were mainly active against Gram-positive bacteria and yeast and had bactericidal action in certain bacteria and bacteriostatic action in other ones. However, they had all fungistatic effect on C. albicans ATCC 10231. According to these results, Algerian propolis can be considered as a source of natural bioactive principles for dietary, pharmacological and medicinal applications.