RESUMEN
Four chain-extended analogs (12a-12d) and two related de-O-sulfonated analogs (13a and 13c) by introducing alkyl groups (a: R = C3H7, b R = C6H13, c: R = C8H17, d: R = C10H21) to the side chains of salacinol (1), a natural α-glucosidase inhibitor from Ayurvedic traditional medicine "Salacia", were synthesized. The α-glucosidase inhibitory activities of all the synthesized analogs were evaluated in vitro. Against human intestinal maltase, the inhibitory activities of 12a and 13a with seven-carbon side chain were equal to that of 1. In contrast, analogs (12b-12d, and 13c) exhibited higher level of inhibitory activity against the same enzyme than 1 and had equal or higher potency than those of the clinically used anti-diabetics, voglibose, acarbose, and miglitol. Thus, elongation of the side chains of 1 was effective for specifically increasing the inhibitory activity against human intestinal maltase.
Asunto(s)
Inhibidores de Glicósido Hidrolasas/farmacología , Intestinos/enzimología , Salacia/química , Alcoholes del Azúcar/farmacología , Sulfatos/farmacología , alfa-Glucosidasas/metabolismo , Animales , Relación Dosis-Respuesta a Droga , Inhibidores de Glicósido Hidrolasas/síntesis química , Inhibidores de Glicósido Hidrolasas/química , Humanos , Medicina Ayurvédica , Conformación Molecular , Ratas , Relación Estructura-Actividad , Alcoholes del Azúcar/síntesis química , Alcoholes del Azúcar/química , Sulfatos/síntesis química , Sulfatos/químicaRESUMEN
A facile and highly diastereoselective approach toward the synthesis of potent salacinol-type α-glucosidase inhibitors, originally isolated from plants of the genus "Salacia", was developed using the S-alkylation of thiosugars with epoxides in HFIP (â¼90%, dr, α/ß = â¼ 26/1). The dr ratio of the product was significantly improved by the protocol as compared to that of the conventional S-alkylation of thiosugars (dr, α/ß = â¼ 8/1). The protocol could be used for gram scale synthesis of the desired compounds. The 3'-O-benzylated salacinol analogs, which are the most potent in vitro inhibitors to date, were synthesized and evaluated in vivo; all analogs suppressed blood glucose levels in maltose-loaded mice, at levels comparable to those of the antidiabetic agent, voglibose.
Asunto(s)
Inhibidores de Glicósido Hidrolasas/farmacología , Alcoholes del Azúcar/farmacología , Sulfatos/farmacología , alfa-Glucosidasas/metabolismo , Relación Dosis-Respuesta a Droga , Inhibidores de Glicósido Hidrolasas/síntesis química , Inhibidores de Glicósido Hidrolasas/química , Humanos , Intestinos/enzimología , Conformación Molecular , Estereoisomerismo , Relación Estructura-Actividad , Alcoholes del Azúcar/síntesis química , Alcoholes del Azúcar/química , Sulfatos/síntesis química , Sulfatos/químicaRESUMEN
The antidiabetic effect of a hot water extract of stems of Salacia chinensis (SCE) was evaluated in vivo in KK-Ay mice, a typical type 2 diabetes mellitus mice model. Administration of CE-2 dietary feed containing 0.25 and/or 0.50% of SCE for three weeks to KK-Ay mice significantly suppressed the elevation of both blood glucose and HbA1c levels without significant changes in body weight or food intake. Glucose tolerance was improved by administration to KK-Ay mice for 27 days of AIN93M purified dietary feed containing 0.12% of SCE. No suppressive effect with respect to HbA1c level was observed when AIN93M/Glc dietary feed in which all digestible glucides were replaced with glucose was administered with SCE. Thus, α-glucosidase inhibitory activity approved as the mechanism of action of the antidiabetic effect of SCE by in vitro investigation was reconfirmed also in in vivo studies. Evaluation of the α-glucosidase inhibitory activity of the active constituents, salacinol (1), kotalanol (3), and neokotalanol (4), by employing human α-glucosidases revealed that these compounds inhibited them as potently (IC50 = 3.9-4.9 µM for maltase) as they inhibited rat small intestinal α-glucosidase. The principal sulfonium constituents (1-4) were highly stable in an artificial gastric juice. In addition, 1-4 were hardly absorbed from the intestine in an experiment using the in situ rat ligated intestinal loop model. The results indicate that these sulfoniums are promising leads for a new type of anti-diabetic agents.