Effect of fennel essential oil and flaxseed oil on blood parameters, insulin resistance, and histological structure of ovaries in rats suffered polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is known as a reproductive disorder in mammalian females. Medical plants are known from ancient times and herbal therapy is common in many countries for preventing and treating different diseases or disorders. The effect of fennel essential oil and/or flaxseed oil on body weight, blood parameters, and histological structure of ovaries and pancreas in rat suffered PCOS, was investigated. Thirty adult Wistar female rats (BW=260±20 g) that 24 of them suffered by PCOS by a single intra-muscular (IM) injection of 4 mg/kg estradiol-valerate (EV) were allocated to the treatments. Fennel essential oil (100 mg/kg BW/day) and flaxseed oil (429 mg/kg BW/day or 240 mg ω-3/kg BW/day) were fed using oral gavage in a 50-day period after PCOS induction. Serum concentration of progesterone, testosterone, insulin, and glucose, and also HOMA-IR, HOMA-β, and QUICKI indices were affected (P< 0.05) by the treatments. Fennel essential oil increased (P <0.05) blood insulin hormone compared to PCOS and control groups. Our results showed that induction of PCOS in rats increased (P <0.05) fasting blood glucose, but consumption fennel essential oil or flaxseed oil decreased its concentration to the normal threshold. Results of this study showed that feeding fennel essential oil or flaxseed oil due to their anti-diabetic effects and anti-oxidative properties improved the body mass index, serum glucose, insulin and progesterone concentration, and HOMA-IR, HOMA-β, and QUICKI indices in rats suffered PCOS.