Chemical composition and in vitro antioxidant and antitumor activities of Eucalyptus camaldulensis Dehn. leaves

Euclayptus camaldulensis leaves have been widely used in folk medicines for treatment of various ailments. In current study an effort was made to explore chemical composition and biological (in vitro antioxidant and antitumor) potentials of three different solvent (methanol, chloroform and hexane) extracts of E. camaldulensis leaves. For this purpose, different solvent extracts of E. camaldulensis leaves were characterized by GC-MS and polyphenolic (phenolic acids and flavonoids) compounds in them were quantified by HPLC. Total phenolic and total flavonoid contents of each extract were explored by colorimetric assays. Antioxidant activity and total antioxidant contents of different extracts were determined by free radical (DPPH) scavenging and ferric reducing antioxidant power (FRAP) assays, respectively. Potato disc assay was used to estimate antitumor potential of each extract. GC/MS analysis led to identification of eucalyptol as major constituent of methanol (31.86%) and chloroform (45.94%) extracts. Palmitic acid (31.06%) was the dominating component of hexane extract. Different phenolic acids (gallic acid, p-hydroxybenzoic acid, syringic acid and vanillic acid) and flavonoids (catechin and quercetin) were highly abundant in methanol extract. The hierarchy of antioxidant activity for three extracts was: methanol (IC50 = 89.11 μg/mL) > chloroform (IC50 = 154.8 μg/mL) > hexane (IC50 = 532.9 μg/mL). Similar order of extracts was observed for antitumor and colorimetric assays. Hexane extract of E. camaldulensis exhibited the maximum amount of total antioxidant contents (34.81 ± 0.67 mg GAE/g of plant extract). These results demonstrate E. camaldulensis leaf extracts as potential source of bioactive compounds and exhibit remarkable antioxidant and antitumor activities.