Induction of Biologically Active Flavonoids in Cell Cultures of Morus nigra and Testing their Hypoglycemic Efficacy

The antidiabetic activity of both leaves and MJ-treated cell cultures of Morus nigra was evaluated after their oral administration to streptozotocin-induced diabetic rats. 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 μU/ml (control) to 14.6 ± 0.43 μU/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 cell weight and flavonoid content were monitored between day zero and 12. The linear increase in fresh weight was found to be parallel to flavonoids production. Cell cultures treated with 100 μM 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

Cardiac glycosides from shoot cultures of Cryptostegia grandiflora

Cardiac glycosides in shoot cultures of Cryptostegia grandiflora were identified when grown in modified MS medium. The change in shoot segments and cardiac glycosides content was followed between day zero and day 12 at 2-day intervals. The content of cardiac glycosides in leaves and shoot cultures of Cryptostegia grandiflora was monitored by HPLC. Two major compounds were detected and isolated from shoot cultures extract, named oleandrigenin 3-O-β – glucopyranosyl-(1→4) – β-cymaropyranosyl-(1→4)-β-digitoxopyranoside (cryptostigmin I) and oleandrigenin 3-O-β – glucopyranosyl-(1→4)-α-rhamnopyranoside (cryptostigmin II). The structures of the isolated compounds were verified by means of MS and NMR spectral analysis, as well as by comparison with authentic samples. The leaves and shoot cultures were analyzed for their cardiac glycosides content. The shoot cultures inoculated into MS-based culture media supplemented with 0.1 mg L-1 BA, 30 g L-1 sucrose, 0.1 g L-1 myo-inositol and 0.1 g L-1 ascorbic acid were found to contain a quantity of cardiac glycosides that was about four fold the cardiac glycosides content of leaves extract