The seeds of Ocimum basilicum have traditionally been used for the prevention and treatment of a number of diseases in Xinjiang of China. In this study, six polysaccharide extracts were isolated from the seeds of O. basilicum by sequential extraction and purified. After methanolysis, the monosaccharide compositions of the six polysaccharide extracts were analyzed by high-performance thinlayer chromatography (HPTLC) on HPTLC plates silica gel 60 with a mixture of isopropyl acetate-ethyl acetate-methanol-water (5:4:1:0.1, v/v). After derivatization with the aniline diphenylamine o-phosphoric acid reagent, densitometric quantitation was performed by absorbance measurement at 370 or 630 nm. The results revealed that the polysaccharides in O. basilicum seeds consisted primarily of fructose (hRF 80), glucuronic acid (hRF 58), galacturonic acid (hRF 51), rhamnose (hR F 40), xylose (hRF 25), arabinose (hRF 18), and galactose (hRF 9). Xylose, glucuronic acid, and fructose were the three major components found and account for 45, 31, and 21%, respectively. All extracts contained uronic acids, ranged 3 to 24%. An unknown monomeric unit above glucuronic acid was characterized by mass spectrometry (MS) to be a hexuronic acid, and HPTLC-MS proved to be a well suited method for characterization of polysaccharide-based biopolymers and assignment of its monomers. The polysaccharide extracts (aqueous cold, aqueous hot, acidic, and alkaline) showed inhibitor activities of protein tyrosine phosphatase 1B in vitro with half maximal inhibitory concentration (IC50) values of 8.2, 2.2, 70.9, and 0.8 μg mL-1, respectively. For the first time, a molecular basis was provided to explain the hypoglycemic effect of the seeds of O. basilicum that has been used as antidiabetic adjuvant in traditional Chinese medicine.
Chinese Acad Sci, Xinjiang Tech Inst Phys & Chem, Lab Plant Resources & Chem Arid Zone, Urumqi 830011, Xinjiang, Peoples R China;Chinese Acad Sci, Grad Univ, Beijing 100039, Peoples R China;Xinjiang Med Univ, Sch Pharm, Urumqi 830054, Xinjiang, Peoples R China;Univ Giessen, Inst Nutr Sci, D-35392 Giessen, Germany
Yili, Abulimiti,Yimamu, Hurxid,Ghulameden, Saideiahmat,et al. Determination of antidiabetic polysaccharides of ocimum basilicum seeds indigenous to xinjiang of China by high-performance thin-layer chromatography-UV/Vis-mass spectrometry[J]. JPC-JOURNAL OF PLANAR CHROMATOGRAPHY-MODERN TLC,2014,27(1):11-18.