Glucopyranoside flavonoids isolated from leaves of Spinacia oleracea (spinach) inhibit the formation of advanced glycation end products (AGEs) and aldose reductase activity (RLAR).

BACKGROUND AND PURPOSE: The formation and accumulation of advanced glycation end products (AGEs) and rat lens aldose reductase (RLAR) generated in the glycation process play an outstanding role in the complications of diabetes. Owing to the adverse effects of AGEs on diabetic patients, the search for new anti-AGE agents from plants without side effects has had significant interest from the researchers in the last decades for the development of a therapy that improves diabetic complications. Spinach could reverse the formation of AGEs and RLAR. This study aimed to investigate the ability of 10 known glucopyranosides flavonoids isolated from Spinacia oleracea on the formation of AGEs and RLAR in vitro and in vivo experiments. MATERIALS AND METHODS: Methanol extract of leaves of spinach was subjected to bioassay-guided fractionation using to silica gel column chromatographic followed by gel filtration by Sephadex LH-20. BSA glucose system and in vitro bioassays using rat lens aldose reductase (RLAR) were employed to evaluated inhibitory activity on the formation of AGEs. The induced diabetes in zebrafish by immersing in a 111 mM glucose solution for 14 days, revealed increased glycation of proteins in the eyes. Measurements of glycated hemoglobin and fructosamine were used to verify the anti-AGEs effect of the isolated flavonoids. KEY RESULTS: Through bioassay-guided fractionation of methanol extract of leaves spinach, ten known glucopyranoside flavonoids (1-10) have been isolated, and spectroscopic studies established their structures. Among the isolated compounds are: patuletin-3-O-(2"-coumaroylglucosyl)-(1→6)-[apiosyl-(1→2)]- ß-d-glucopyranoside (7), patuletin 3-O-(2"-feruloyl glucosyl)-(1→6)-[apiosyl-(1→2)]- ß-d-glucopyranoside (8), they have shown potent inhibition on AGEs formation, stronger than the positive controls used in the different experiments. CONCLUSION AND IMPLICATIONS: The findings indicated that glucopyranoside flavonoids found in Spinacia oleracea might have therapeutic potential for decreasing protein glycation, and might ameliorate AGE-related diabetic complications.

Spinacia oleracea Linn Considered as One of the Most Perfect Foods: A Pharmacological and Phytochemical Review.

BACKGROUND: Leaves of Spinacia oleracea have been widely used as vegetarian foods. Some studies on the chemical composition of spinach have shown that it contains a high content of micronutrients (vitamins and minerals), and has an important economic value with some agronomic advantages. S. oleracea in traditional medicine is reported to cure more than one health problem. OBJECTIVE: This review focuses on the ethnopharmacological uses and pharmacological and phytochemical studies of Spinacia oleracea. METHODS: Information on S. oleracea was obtained via electronic search of scientific databases such as Scopus, PubMed, Google Scholar, Scirus, Science Direct, Scielo, Web of Science, Medline, Springerlink, BioMed Central (BMC), and SciFinder for publications on this plant. In addition, books on medicinal herbs were also consulted. RESULTS: Approximately 100 chemical compounds were isolated and characterized from S. oleracea. The major active components of the plant are flavones, flavanols, methylenedioxyflavonol glucuronides, glucuronides, and carotenoids, which were extensively investigated. This review revealed potential pharmacological properties of these isolated compounds such as anti-obesity, anti-α-amylase, bileacid binding capacity, anti-mutagenic, anti-oxidant, anticancer, anti-inflammatory, cognitive and mood effect, hypoglycemic, and anti-hypertriglyceridemia. CONCLUSION: S. oleracea is an important edible plant also used for ethnomedical therapy of obesity, inflammation of lungs, lumbago, flatulence, and treatment of urinary calculi. Pharmacological and phytochemical studies of this plant including bioactives, which have been adequately studied, support its uses in traditional medicine. Additionally, prospects and future trends of this plant are proposed.