Laminar flow

A rotary evaporator (Rotavapor R-II, Buchi, Switzerland) was utilized for the solvent evaporation process. The antioxidant assays, as well as quantification assays, were conducted using a spectrophotometer (UV-1601, Shimadzu, Japan). The qualitative identification of phenolic compounds was performed using Waters 2690 Alliance HPLC system and Waters 996 photodiode array detector, Milford, CT, USA. Laminar Flow (model 1386, Thermo Fisher Scientific, Waltham, MA, USA) and BIO-RAD microplate reader (model iMark, Japan) were utilized. Centrifugation of the AgNPs was done using a cooling centrifuge (PRO-Research K241R; Centurion, West Sussex, UK), characterization of the prepared NPs was done using a double-beam spectrophotometer (V630, Jasco, Tokyo, Japan), transmission electron microscope (TEM) (JTEM model 1010, JEOL^®, Tokyo, Japan) and Malvern Zetasizer (Nano ZS, Malvern Instruments Ltd., Malvern, UK).

The qualitative identification of phenolic and flavonoid compounds in Propolis was carried out by HPLC by Nawah Scientific Inc. (Mokatam, Cairo, Egypt). A Waters 2690 Alliance HPLC system equipped with Waters 996 photodiode array detector, Milford, CT, USA. Laminar Flow (model 1386, Thermo Fisher Scientific, Waltham, MA, USA). A stock solution of 10 different standards in methanol was prepared and filtered using a 0.22 μm syringe filter, then 10 μl was injected. 137.8 mg/ml of propolis were accurately weighted and sonicated for 15 min, filtered using a 0.22 μm Nylon syringe filter, then 10 μl was injected. The gradient method that was eventually chosen following a series of preliminary studies uses a mixture of 0.1% Phosphoric acid in water: Acetonitrile (mobile phase). The total runtime of the method was 80 minutes. The absorbance was measured at 280 nm. The total phenolic content (mg/mL) was calculated using the standards; Gallic acid, chlorogenic acid, ellagic acid, and caffeic acid. The total flavonoid content (mg/mL) was calculated using the following standards; catechin, rutin, hesperidin, apigenin, kaempferol, and quercetin.