Neokotalanol, a potent α-glucosidase inhibitor isolated from Salacia reticulata, was synthesized through a key coupling reaction between a perbenzylated thiosugar and an appropriately protected perseitol triflate derived from D-mannose. This key step was found to be quite temperature dependent, and a simultaneous cyclization of the triflate leading to a characteristic 2,4,7-trioxabicyclo[4.2.1]nonane system was detected.
Enzyme Inhibitors ; chemical synthesis ; chemistry ; Glycoside Hydrolase Inhibitors ; Plant Extracts ; chemical synthesis ; chemistry ; Salacia ; chemistry

Nine compounds were isolated from the 90% ethanol extract of Salacia polysperma by silica gel, Sephadex LH-20 column chromatography, together with preparative HPLC methods. Based on HR-ESI-MS, MS, 1D and 2D NMR spectral analyses, the structures of the nine compounds were identified as 28-hydroxy wilforlide B(1), wilforlide A(2), 1β,3β-dihydroxyurs-9(11),12-diene(3),(-)-epicatechin(4),(+)-catechin(5),(-)-4'-O-methyl-ent-galloepicatechin(6), 3-hydroxy-1-(4-hydroxy-3-methoxy-phenyl)propan-1-one(7),(-)-(7S,8R)-4-hydroxy-3,3',5'-trimethoxy-8',9'-dinor-8,4'-oxyneoligna-7,9-diol-7'-aldehyde(8), and vanillic acid(9). Compound 1 is a new oleanane-type triterpene lactone. Compounds 1, 3, 4, 7-9 were isolated from the Salacia genus for the first time. All compounds were assayed for their α-glucosidase inhibitory activity. The results suggested that compound 8 exhibited moderate α-glucosidase inhibitory activity, with an IC_(50) value of 37.2 μmol·L~(-1), and the other compounds showed no α-glucosidase inhibitory activity.
Salacia/chemistry* ; alpha-Glucosidases ; Triterpenes/pharmacology* ; Magnetic Resonance Spectroscopy ; Ethanol ; Molecular Structure

At present, lifestyle-related diseases are one of the most critical health issues worldwide. It has been reported that lipopolysaccharide derived from a Gram-negative bacteria (IP-PA1) symbiotic with wheat exhibited several advantageous biological effects, such as the reduction of plasma glucose levels in NOD mice and low-density lipoprotein (LDL) levels in WHHL rabbits. In this study, the beneficial effects on plasma glucose and lipids of a tea (SI tea) consisting of IP-PA1 and Salacia (which contains an inhibitor of alpha-glucosidase) were investigated in the KK-Ay/TaJcl type 2 diabetic model mice and in human subjects with premetabolic syndrome in a double-blind, randomized study. SI tea significantly decreased plasma glucose levels in KK-Ay/TaJcl mice. A clinical trial of SI tea was performed with 41 subjects between the ages of 40 and 69, who belonged either to a high plasma glucose group (HG: FPG 100-125 mg/dl) or to a hyperlipidemia group (HL: TG > or = 150 mg/dl, or LDL > or = 120 mg/dl, or HDL < 40 mg/dl). These subjects ingested either Salacia without IP-PA1 (the control) or SI tea. Blood samples were collected at 0, 30, and 60 days after initiating SI tea treatment, and were measured for FPG, HbA1c, TG, LDL, and HDL. These results showed that SI tea reduced FPG and HbA1c more rapidly than the control in the HL group, and also significantly improved LDL and HDL levels in the HG group. Thus, SI tea may be helpful in preventing lifestyle-related diseases.
Animals ; Cholesterol ; Fasting ; Glucose ; Gram-Negative Bacteria ; Humans ; Hyperlipidemias ; Lipoproteins ; Mice ; Mice, Inbred NOD ; Plasma ; Rabbits ; Salacia ; Tea ; Triticum

Chemical constituents of the roots and stem of Salacia hainanensis Chun et How were isolated and purified with column chromatography on silica gel, Sephadex LH-20 and preparative HPLC. Their structures were elucidated based on physicochemical and spectral spectroscopic analysis. Depending on the activities of anti-alpha-glucosidase and inhibiting AGEs (advanced glycation end products, AGEs) formation in vitro, nine compounds were identified as 26, 27-dihydroxy-7, 24-tirucalladien-3-one (1), abruslactone A (2), lupeol (3), 21alpha, 30-dihydroxy-D: A-friedooleanan-3-one (4), 15alpha-hydroxyfriedelan-3-one (5), friedelin (6), mangiferin (7), epicatechin (8) and beta-sitosterol (9), separately. Among them, compound 1 is a new compound, and compound 2 was isolated from the Salacia genus for the first time, while, compounds 3, 4, 5, 8 were obtained from this plant for the first time.
Catechin ; analogs & derivatives ; chemistry ; isolation & purification ; Molecular Structure ; Pentacyclic Triterpenes ; chemistry ; isolation & purification ; Plant Roots ; chemistry ; Plant Stems ; chemistry ; Plants, Medicinal ; chemistry ; Salacia ; chemistry ; Steroids ; chemistry ; isolation & purification ; Triterpenes ; chemistry ; isolation & purification ; Xanthones ; chemistry ; isolation & purification