In vitro Cytotoxicity, Antioxidant, and Anti-inflammatory Activities of Eucalyptus camaldulensis Leaf Extracts

Abstract

Chronic inflammation and oxidative stress are key contributors to the onset and progression of several degenerative diseases. Medicinal plants play a vital role in their management due to their rich content of bioactive compounds, which possess antioxidant and anti-inflammatory properties. This study evaluated the cytotoxic, antioxidant, and anti-inflammatory activities of Eucalyptus camaldulensis leaf extracts collected in Kano, Nigeria. The powdered leaves were extracted with ethanol and fractionated into n-hexane, chloroform, ethyl acetate, and methanol fractions. Antioxidant activity was assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, anti-inflammatory activity by inhibition of protein denaturation, and cytotoxicity using the brine shrimp lethality test. The methanol extract exhibited the strongest antioxidant effect (IC₅₀ = 4.785 µg/mL), which was lower in potency than ascorbic acid (IC₅₀ = 0.943 µg/mL). The n-hexane fraction demonstrated the highest anti-inflammatory activity (IC₅₀ = 3.215 µg/mL) and cytotoxicity (LC₅₀ = 3.810 µg/mL), while the methanol fraction was non-toxic (LC₅₀ > 1000 µg/mL). These findings indicate that Eucalyptus camaldulensis possesses solvent-dependent biological activities, with the methanol fraction showing strong antioxidant and safe pharmacological properties, and the n-hexane fraction displaying significant anti-inflammatory and cytotoxic effects. The study provides scientific support for the traditional use of Eucalyptus camaldulensis and suggests its potential as a source of natural therapeutic agents. Further studies should focus on the isolation, characterization, and in vivo evaluation of its bioactive compounds.