BackgroundRose-scented geranium (Pelargonium graveolens L’Hér.), which is used in traditional Tunisian folk medicine for the treatment of hyperglycaemia, is widely known as one of the medicinal herbs with the highest antioxidant activity. The present paper is conducted to test the hypoglycemic and antioxidative activities of the leaf essential oil of P. graveolens.MethodsThe essential oil P. graveolens was administered daily and orally to the rats at two doses of 75 mg/kg and 150 mg/kg body weight (b.w.) for 30 days. The chemical composition of P. graveolens essential oil, body weight, serum glucose, hepatic glycogen, thiobarbituric acid-reactive substances (TBARS), the components of hepatic, and renal and serum antioxidant systems were evaluated. The hypoglycemic effect of rose-scented geranium was compared to that of the known anti-diabetic drug glibenclamide (600 μg/kg b.w.).ResultsAfter the administration of two doses of essential oil of Pelargonium graveolens L’Hér. together with glibenclamide which is known by its antidiabetic activities and used as reference (600 μg/kg b.w.), for four weeks, the serum glucose significantly decreased and antioxidant perturbations were restored. The hypoglycemic effect of P. graveolens at the dose of 150 mg/kg b.w. was significantly (p< 0.05) more effective than that of glibenclamide. It is through the histological findings in hepatic and renal tissues of diabetic rats that these beneficial effects of geranium oils were confirmed.ConclusionsIt suggests that administration of essential oil of P. graveolens may be helpful in the prevention of diabetic complications associated with oxidative stress. Our results, therefore, suggest that the rose-scented geranium could be used as a safe alternative antihyperglycemic drug for diabetic patients.

Pelargonium graveolens (Geraniaceae) was characterized with respect to its chemical composition, antioxidant potential and antimicrobial activities. This is the first investigation focusing on the comparison of both essential oil and polar extracts from this species. The chemical composition of the essential oil of the aerial parts of P. graveolens was analyzed by gas chromatography/mass spectrometry. The main constituents of the oil were found to be β-citronellol (21.9%), citronellyl formate (13.2%), geraniol (11.1%), 10-epi-γ-eudesmol (7.9%), geranyl formate (6.2%) and (l)-linalool (5.6%). Nine flavonoids were identified by high-performance liquid chromatography-MS in leaf and flower extracts. Kaempferol 3-O-rhamnoside-glucoside, isorhamnetin aglycone, quercetin 3-O-glucoside, kaempferol 3,7-di-O-glucoside, quercetin 3-O-pentose and kaempferol 3-O-glucoside, quercetin 3-O-rhamnoside-glucoside, quercetin 3-O-pentoside-glucoside, myrisetin 3-O-glucoside-rhamnoside flavonoids were detected in methanolic and aqueous extracts, respectively. The total flavonoids ranged between 29.9 and 78.2 mg QE/g in flower water and methanol extracts, respectively, and 22.5 and 71.2 mg QE/g dry weight in leaf water and methanol extracts, respectively. The highest antioxidant activities using two methods of free radical scavenging capacities were obtained with the essential oil (9.16 mM of Trolox and 2.68 µg/ml). All P. graveolens essential oil and polar extracts were active against at least one bacterium.

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