Seasonal Variation in the Anti-Diabetic and Hypolipidemic Effects of Momordica charantia Fruit Extract in Rats

Aims: To investigate seasonal variation in anti-diabetic and hypolipidemic activities of Momordica charantia fruits harvested at different seasons of the year, namely spring, summer, autumn and winter.
Methodology: Air-dried and pulverized fruit samples were extracted by soaking in 70% methanol for 72h. The filtrate was concentrated using rotary evaporator. The yields of spring (MME), summer (JME), autumn (SME) and winter (DME) samples were 8.4, 7.1, 4.8 and 5.1% respectively. For each of the four fruit samples, rats were divided into six groups of six rats each. First group served as normal control (non-diabetic). The remaining five groups were made diabetic by administering alloxan (120mg/kg body weight) intraperitoneally. Second group served as diabetic control. Third, fourth and fifth groups were treated with oral doses of 200, 400 and 600mg/kg body weight of Momordica charantia fruit extracts respectively. The sixth group received oral dose of glibenclamide (5mg/kg body weight) which served as the standard drug. These treatments were repeated daily for 28 days.
Results: Treatment with methanol extracts of Momordica charantia caused a significant (p<0.01) and dose-dependent changes with respect to blood glucose level and lipid profile in all the four samples, when compared with the untreated animals. The highest activity was observed with spring sample, followed by the summer sample. Autumn and winter samples have more or less similar but lesser effects than summer sample.
Conclusion: The results of this study showed that anti-diabetic and hypolipidemic effects of Momordica charantia fruit extract vary during different seasons of the year. The spring sample produced the highest activity. This suggests that the active principles in Momordica charantia fruit that are responsible for its antidiabetic and hypolipidemic activity vary in quantity and/or quality during different seasons of the year and reach the peak during spring.