Fennel Essential Oil as a Complementary Therapy in the Management of Diabetes

Diabetes is a serious pathology that affects a significant number of people worldwide. Its progression is rapid and leads to serious complications if glycemic control is missing. The micro and macrovascular complications of diabetes produce disabilities over time that affect the daily lives of patients. The major challenge of diabetes therapy is to reach a stable glycemic state and to delay the onset of specific complications. Aromatherapy is considered an alternative or complementary therapy, but in recent years, there has been a tendency to overuse essential oils. The present study was designed to evaluate and compare the effects produced by the topical and oral administration of fennel essential oil to diabetic rats. Eighteen compounds in fennel essential oil were identified by gas chromatography-mass spectrometry (GC-MS) analysis. The major compounds were trans-anethole (64.6%) and fenchone (24.5%). The in vivo study revealed that after a four-week treatment with fennel essential oil, the rats' glycemic levels were significantly reduced (p ≤ 0.05). Furthermore, there were no differences between the two routes of administration. In addition, an ex vivo study underlined the potential effect of this essential oil in the prevention of cataract formation.