Hypoglycemic activity of a novel anthocyanin-rich formulation from lowbush blueberry, Vaccinium angustifolium Aiton

Abstract

Blueberry fruits are known as a rich source of anthocyanin components. In this study we demonstrate that anthocyanins from blueberry have the potency to alleviate symptoms of hyperglycemia in diabetic C57b1/6J mice. The anti-diabetic activity of different anthocyanin-related extracts was evaluated using the pharmaceutically acceptable self-microemulsifying drug delivery system; Labrasol. Treatment by gavage (500 mg/kg body wt) with a phenolic-rich extract and an anthocyaninenriched fraction formulated with Labrasol lowered elevated blood glucose levels by 33 and 51%, respectively. The hypoglycemic activities of these formulae were comparable to that of the known anti-diabetic drug metformin (Baily and Day, 2004; 27% at 300 mg/kg). The extracts were not significantly hypoglycemic when administered without Labrasol, demonstrating its bio-enhancing effect, most likely due to increasing the bioavailability of the administered preparations. The phenolic-rich extract contained 287.0 ± 9.7 mg/g anthocyanins, while the anthocyanin-enriched fraction contained 595 ± 20.0 mg/g (cyanidin-3-glucoside equivalents), as measured by HPLC and pH differential analysis methods. The greater hypoglycemic activity of the anthocyanin-enriched fraction compared to the initial phenolic-rich extract suggested that the activity was due to the anthocyanin components. Treatment by gavage (300 mg/kg) with the pure anthocyanins, delphinidin-3-O-glucoside and malvidin-3-O-glucoside, formulated with Labrasol, showed that malvidin-3-O-glucoside was significantly hypoglycemic while delphinidin-3-O-glucoside was not.

Plants and Natural Compounds with Antidiabetic Action

“…The hypoglycaemic activity was comparable to that of the known antidiabetic drug metformin (Grace et al, 2009). Jayaprakasam et al (2005) performed in vitro studies on rodent pancreatic β-cells and found that anthocyanins, such as cyanidin-3-glucoside, delphinidin-3-glucoside, and pelargonidin-3-galactoside, as well as the anthocyanidin pelargonidin were efficient in stimulating insulin secretion from pancreatic β-cells.…”

Anthocyanins and Flavonoids of Vaccinium L.

“…Anthocyanins from bilberry alleviated pruritus in a mouse model of chronic allergic contract dermatitiss [158] Rats Flavonoids from fruit residues of V. vitis-idaea could lower serum uric acid and protect kidney in adenine-reduced hyperuricemia [132] Mice Anthocyanins from bilberry showed protective effect on gastric ulcer [159] Mice The bilberry fruit extract, in a dose dependent manner, induced the resolution of liver fibrosis by decreasing oxidative stress and inactivating HSCs via down-regulation of fibrogenic cytokines, TGF-1 and TNF- [160] Rats and Mice Anthocyanins from bilberry provided moderate protection against Dox-induced cardiac and hematopoietic damage [161] Mice Blueberry extract showed antinociceptive activity [162] Mice Bilberry extract showed protective effective against endotoxin-induce uveitis [163] Mice Anthocyanins from lowbush blueberry showed hypoglycemic activity [164] Mice Bilberry extract played an important role in protecting against restraint stress-induced liver damage by both scavenging free radicals activity and lipid peroxidase inhibitory effect [165] Mice Bilberry extract reduced the degree of oxidative stress and kidney damage induced by KBrO3 [166] Mice V. oxycoccos berries extract showed preventive effect on acetic acid-induced colitis [167] Mice V. ashei berries extract showed improvement performance in memory tasks and had protective effects on brain DNA [168] Mice extract of V. myrtillus significantly decrease the level of glucose and fructosamine in alloxan induced NOD [169] Rats Anthocyanosides from V. myrtillus appear to be effective in preventing the increase in capillary filtration of albumin (CFA) and the failure of lymphatic uptake of interstitial albumin [170] Mice Extract from V. ashei produced antinociceptive effects [162] Mice Extract from V. corymbosum did not induce in vivo DNA damage in peripheral blood cells of 12-day old female or male Swiss mice but the micronucleus assay indicated that the extract presented clastogenic or aneugenic effects or dihydroflavonol stage, and methylation, glycosylation, and dimethylallylation are also possible, increasing the range of compounds enormously.…”

Carotenoids: Properties, Applications and Market

“…Entretanto, a ingestão dessas substâncias tem sido associada a efeitos nocivos como: hiperatividade, citoxicidade, genotoxicidade e ansiedade. [41][42][43] Esse cenário tem impulsionado o mercado consumidor a escolher produtos à base de corantes naturais, posto que apesar de mais caros, são mais seguros e, muitas vezes, apresentam propriedades funcionais, 4 a exemplo das betalaínas, antocianinas e carotenoides que podem atuar na proteção do DNA e como agentes hipoglicêmicos e antioxidantes, 44,45 respectivamente.…”