In brief, flavonoid glycosides were extracted and hydrolysed to their aglycones with HCl in 50% aqueous
methanol. The extraction solution thus obtained consisted of 1.2 M HCl in 50% aqueous methanol (v/v). After refluxing at
90 C for 2 h with regular swirling, the extract was allowed to cool and was subsequently made up to 100 ml with methanol and sonicated for 5 min.