Synthesis of hyaluronic acid or O-carboxymethyl chitosan-stabilized ZnO–ginsenoside Rh2 nanocomposites incorporated with aqueous leaf extract of Dendropanax morbifera Léveille: in vitro studies as potential sunscreen agents

The present study elucidates the synthesis of hyaluronic acid (HA) or O-carboxymethyl chitosan (CMC)-stabilized zinc oxide nanocomposites (ZnONcs) incorporated with aqueous leaf extract of Dendropanax morbifera Leveille to enhance the water solubility of hydrophobic ginsenoside Rh2. Ginsenosides are triterpenoid saponins isolated from Panax ginseng and exhibit potent pharmacological effects and unique biological properties. The polymers were integrated to accommodate steric stabilization, provide terminal carboxylic groups for ginsenoside conjugation, and grant intrinsic clinical benefits for topical administrations. D. morbifera leaf extract was incorporated into the nanocomposites to enhance their antioxidant activities against DPPH and ABTS+ radicals and water solubilization. Ginsenoside Rh2 was covalently conjugated via carbodiimide-intermediated esterification to form water-dispersible Rh2–HA–ZnONcs and Rh2–CMC–ZnONcs. Binding of ginsenoside Rh2 to ZnONcs was detected by FTIR and LC-MS. In vitro evaluation of ginsenoside-conjugated ZnONcs revealed that Rh2 conjugation increased the SPF rating and reduced the cytotoxicity in human keratinocyte (HaCaT) cells compared to unconjugated polymer-functionalized ZnONcs. Overall, Rh2–HA–ZnONcs and Rh2–CMC–ZnONcs show promising results as multi-functional carriers for ginsenoside Rh2 and can potentially be implemented as novel bioactive sunscreen agents.