Anti-inflammatory, Analgesic Activity and Toxicity of Two Pelargonium inquinans Ait Essential Oils: Wild and Cultivated

Comparative chemical composition of the essential oils of wild and cultivated P. inquinans fresh leaves and stem was determined and the oils were evaluated for their anti-inflammatory, analgesic and cytotoxicity (acute oral toxicity profile) properties. Fresh leaves and stem of wild and cultivated P. inquinans were hydrodistilled using Clevenger apparatus. The chemical composition of the essential oils obtained from the wild and cultivated was determined using gas chromatography-flame ionization detector and gas chromatography-mass spectrometry. The four oils were evaluated for analgesic activities using acetic acid-induced writhings on hot plate nociception models in mice; while their anti-inflammatory effect was determined using the egg albumin-induced rat paw oedema method in rats. Cytotoxicity test was done using Lorke's method on mice. Camphor (46.5 %), phytol (14.2 % - 20.5 %), alpha-caryophyllene (17.2 % - 25.8 %), beta-caryophyllene (1.7 % -25.2 %), sabinene (27.8 %), linalool (15.3 %) and alpha-terpineol (8.7 %) were the major components of wild and cultivated P. inquinans. The leaf and stem oils from the wild and cultivated plants displayed LD50 >= 5000 mg/kg, indicating they are non-toxic orally. The oils also showed significant (p<0.05-0.001) decrease in number of writhes induced by the acetic acid compared to vehicle, and also caused significant (p<0.05-0.001) delay in reaction time on the hot plate at 60 and 90 min post-treatment and significantly (p<0.05 and 0.001) reduced oedema size caused by the egg albumin injection compared to the vehicle. The oils from the wild plant source however showed more potency when compared to the cultivated. The wild and cultivated P. inquinans leaf and stem essential oils displayed significant but comparable analgesic and anti-inflammatory activities in rodents.