The present study was aimed to investigate antidiabetic activities of Allium paradoxum, Buxus hyrcana, Convolvulus persicus, Eryngium caucasicum, Heracleum persicum, Pimpinella affinis, Parrotia persica, Primula heterochroma, Pyrus boissieriana, Rheum turkestanicum, Ruscus hyrcanus, and Smilax excels. In the following, the study was conducted to isolate active phytochemicals of the most potent plants, R. turkestanicum and H. persicum.
A sequential extraction method used to obtain n-hexane, ethyl acetate, and methanol extracts of various parts of the plants. DPPH scavenging, α-amylase and α-glucosidase inhibition activities, and total phenolic contents of the extracts were investigated. The active compounds were isolated by column chromatography and identified by 1H-, 13C-, 2D-NMR, EI-MS and single-crystal X-ray diffraction.
R. turkestanicum and H. persicum showed significant activities against α-glucosidase enzyme more effective than acarbose, a standard antidiabetic drug. As a result, 17 antidiabetic compounds were isolated from R. turkestanicum and H. persicum. Chrysophanol, physcion, emodin, daucosterol and rhododendrin were isolated from Rheum turkestanicum. Psoralen, bergapten, xanthotoxin, isopimpinellin, angelicin, isobergapten, sphondin, pimpinellin, heratomin, 5-methoxyheratomin, moellendorffiline, and fraxetin were isolated from H. persicum.
Consequently, moellendorffiline and daucosterol introduced as new potent antidiabetic compounds, more potent than acarbose, an antidiabetic drug.