Effect of Oil Pollution on Chemical Composition, Anti-Inflammatory Properties of Stem Extracts of Hyptis suaveolens (L) POIT

Oil pollution poses significant environmental challenges, potentially altering the chemical composition and medicinal properties of plants. This study investigated the impact of oil pollution on the phytochemical profile and anti-inflammatory activity of methanolic stem bark extracts of Hyptis suaveolens (L) POIT, a medicinal plant reported to possess antioxidant, anti-inflammatory, anti-cancerous, anti-diabetic, wound-healing among other uses. Plant samples were collected from polluted (Kaduna Refining and Petrochemical Company) and unpolluted (Murtala Muhammed Square) sites. Gas Chromatography-Mass Spectrometry (GC-MS) analysis identified 37 compounds in polluted stem extracts, compared to 31 in unpolluted extracts, with higher molecular weight compounds and saturated fatty acids in the former. Qualitative phytochemical screening revealed identical phytoconstituents in both extracts, though quantitative differences were statistically non-significant (p > 0.05). Anti-inflammatory activity, assessed via carrageenan-induced paw edema in rats, showed the unpolluted extract (300 mg/kg) exhibited a higher inhibition (49.6%) compared to the polluted extract (49.2%) at the fifth hour post-induction. These findings suggest that oil pollution increases the diversity of chemical compounds in Hyptis suaveolens stem extracts but slightly reduces anti-inflammatory efficacy, highlighting the need for caution in using polluted plants for medicinal purposes.