The antidiabetic activity of both leaves and MJ-treated cell cultures of Morus nigra was evaluated after their oral administration to streptozotocin - induced diabetic rates. The antidiabetic activity of extracts from leaves given to streptozotocin (STZ) - diabetic rats for 10 days increased with increasing doses of leaves extract up to 500 mg/kg/day. The administration of 500 mg/kg/day of leaves extract reduced the concentration of glucose from 370 ± 7.31 mg/dl (control) to 154 ± 6.27 mg/dl and a significant increase in the insulin level from 11.3 ± 0.31 mU/ml (control) to 14.6 ± 0.43 mU/ml was recorded.
Cell suspension cultures were established from the young leaves of Morus nigra cultivated on modified MS medium supplemented with 2.0 mg/l 1-naphthaleneacetic acid (NAA), 0.2 mg/l 6-(furfurylamino)-purine (kinetin). The changes in cells weight and flavonoids content were followed between day zero and 12. The linear increase in fresh weight was found to be parallel to flavonoids production. Cell cultures treated with 100 mM methyl jasmonate for 24 hours showed a noticeable increase in level of flavonoids and significant and more effective hypoglycemic activity than that for extract from leaves. The major flavonoids were isolated by TLC and HPLC and identified as rutin, quercetin, Morusin and cyclomorusin by co-chromatography and mass spectrometry in comparison to samples of authentic reference compounds.