Seasonal variation for the antidiabetic activity of Loranthus micranthus methanol extract

Objective:To determine the season in which the Eastern Nigeria mistletoe,Loranthus micranthus,parasitic on Persea americana possesses optimum antidiabetic activity and to determine the seasonal variation in the constituents.Methods:The antidiabetic activities of the aqueous methanol extracts of the leaves of Eastern Nigeria mistletoe,Loranthus micranthus, harvested in two seasons of the year,the onset of rainy season(April) and the peak of rainy season(July) were compared.The tests were carried out on six(6) groups(A-F) of alloxaninduced diabetic rats.Groups A and B received 200 mg/kg and 400 mg/kg of the April sample extracts respectively while groups C and D received same doses of the July sample extracts. Group E and F which were the positive and negative controls received 10 mg/kg of glibenclamide and 2 ml/kg of 3%tween 20 respectively.The blood glucose levels of the animals were monitored hourly with a glucometer for six hours.The phytochemical analysis of the plant extracts were also carried out by standard procedures.Results:The results showed that group A and B exhibited significant(P【0.05) percentage reduction in the fasting blood sugar(FBS) level of the animals(38.9%and 39.2%respectively) with maximum reduction observed at the 5th and 6th hour respectively compared to glibenclamide(71.3%).Group C showed no significant (P】0.05) FBS reduction(15.9%) while group D exhibited highly significant(P【0.01) reduction (47.5%) with the maximum reduction occurring after 6 hours.The phytochemical analysis of the crude methanol extracts revealed the presence of carbohydrates,glycosides,saponins, tannins,flavonoids,steroids,terpenoids,acidic compounds,resins and oils.These were present in different proportions in both seasons.Conclusions:This study shows that there is a seasonal, dose-dependent variation in the chemical composition viz-a-viz the antidiabetic activity of the plant under study.This activity is highest at the peak of the rainy season.

Antidiabetic principles of Loranthus micranthus Linn.parasitic on Persea americana

Objective:To explore antidiabetic principles of the Eastern Nigeria mistletoe,Loranlhus micranthus Linn,parasitic on Persea Americana.Methods:The weakly acidic fraction of the aqueous methanol extract of the leaves of Loranlhus micranthus(Linn.) was isolated and tested for its antidiabetic activities.The isolation of the weakly acidic fraction was carried out following established physico-chemical based procedures.Furthermore,alloxan-induced diabetic rats were treated intraperitoneally(ip) with 250 mg/kg and 400 mg/kg of the weakly acidic fraction, glibenclamide 10 mg/kg(positive control) and 2 mg/kg of 3%v/v tween 20(negative control).The sugar levels of the treated and untreated animals were determined by withdrawing the blood at regular intervals and testing them with an automated glucometer.The phytochemical analysis of the acidic fraction was carried out using standard procedures.Chromatographic techniques were employed in the subsequent isolation and purification of the constituents of the weakly acidic fraction.Results:It was shown that the maximum effect of the weakly acidic fraction was obtained at 24 hours after administration and was found to be statistically comparable with that of the positive control.The phytochemical analysis revealed the presence of steroids,terpenoids, alkaloids,flavonoids,glycosides,carbohydrates,saponins,and acidic compounds in the crude extract and carbohydrates,flavonoids.terpenoids and oil in the weakly acidic fraction.Further purification of the weakly acidic fraction of the methanol extract using thin layer chromatography shows that toluene:methanol:diethyl amine(3:1:1) and chloroform:methanol:diethyl amine (9:1:1) are the best solvent system for the isolation of the various components of the weakly acidic fraction of the crude methanol extract of Loranlhus micranthus.Conclusions:The present study has led to the conclusion that the weakly acidic fraction of the plant under study has the potent antidiabetic activity and that the various components can be isolated using basic chromatographic techniques.