Asian Journal of Advances in Medical Science

Inflammation is frequently accompanied by oxidative stress, which can disrupt antioxidant defenses and promote tissue injury. Alstonia boonei is widely used in traditional medicine, yet comparative evidence on the dose-dependent antioxidant effects of different plant parts under inflammatory conditions remains limited. This study evaluated the effects of aqueous extracts of A. boonei leaf, stem bark, and root bark on oxidative stress biomarkers in a formalin-induced inflammation model in Wistar rats. Rats were allocated to normal and formalin-induced control groups, an indomethacin-treated reference group, and extract-treated groups. Inflammation was induced by subcutaneous injection of 0.1 mL of 2% formalin into the hind paw on days 1 and 3. Extracts were administered orally at 150, 300, or 600 mg/kg body weight for 21 days; indomethacin (10 mg/kg) served as the standard anti-inflammatory control. Body weight was monitored during the study. After treatment, liver, kidney, and heart tissues were harvested and homogenized for biochemical assays. Oxidative status was assessed using malondialdehyde (MDA) as a lipid peroxidation index, alongside antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT). Data were analyzed using appropriate comparative statistics with significance set at p<0.05. Formalin induction elevated oxidative stress, reflected by increased MDA and altered antioxidant enzyme activities across organs. Leaf extract at lower doses generally improved antioxidant profiles by reducing MDA and supporting SOD/CAT activities, whereas higher doses—particularly of stem and root extracts—tended to worsen oxidative indices and/or dysregulate antioxidant enzymes. Overall, A. boonei exhibited dose- and plant-part–dependent effects, supporting cautious preclinical exploration and emphasizing the need for extract standardization and safety evaluation at higher doses.