Free radical scavenging and cytotoxic properties of acylated and non-acylated kaempferol glycosides from stenochlaena palustris: a perspective on their structure – activity relationships

Flavonoid glycosides that are present in acylated form have good prospect to be developed into therapeutic agents due to their improved biological properties, stability and physico-chemical properties compared to their maternal compounds. The present study aimed to compare the free radical scavenging and cytotoxic activities of a series of acylated and non-acylated kaempferol glycosides isolated from Stenochlaena palustris. The in silico binding interactions of the most cytotoxic glycoside with epidermal growth factor receptor was also evaluated. Results indicated that the free radical scavenging capability and cytotoxicity of kaempferol 3-O-β-D-glucopyranoside were enhanced through acylation with selected hydroxycinnamoyl groups, whereas mono-acylation did not improve both activities. Molecular docking study revealed that di-acylation was essential for the compound to bind to five major active sites of the receptor. Kaempferol 3-O-β-D-glucopyranosides that are di-acylated may be further explored for their chemopreventive and anticancer properties due to their significant antioxidant and cytotoxic properties.