Potential bio-functional properties of Citrus aurantium L. leaf: chemical composition, antiviral activity on herpes simplex virus type-1, antiproliferative effects on human lung and colon cancer cells and oxidative protection

This study examined the antioxidant, anticancer and antiviral properties of the methanolic extracts from bigarade (Citrus aurantium L.) leaves at two development stages. Ferulic acid, naringin and naringenin were the principal phenolic components of young and old leaves. The highest total antioxidant capacity was obtained in young leaf extracts (YLE). These latter also exhibited the highest antiradical DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2 '-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) activities, while the highest iron chelating and reducing power activities were observed in old leaf extracts (OLE). The potent anticancer activity was observed in YLE for human lung carcinoma (A-549) and in OLE for colon adenocarcinoma (DLD-1) cells. YLE showed the highest virucidal effects as compared to OLE and the positive control acyclovir against herpes simplex virus type-1 (HSV-1) propagation in Vero cells during the absorption and replication periods. The young and old leaves might be a source of natural antioxidants and protective agents against oxidative damage.