Seasonal Phytochemical Variation of Anti-Glycation Principles in Lowbush Blueberry (Vaccinium angustifolium)

Abstract

Diabetic hyperglycaemia promotes the production of advanced glycation end-products (AGEs), which play a significant role in the development of complications associated with type 2 diabetes mellitus. Vaccinium angustifolium, a medicinal plant used for the treatment of diabetes, produces a variety of phenolic metabolites with putative anti-diabetic activities. To assess optimal cultivation time, seasonal changes in the concentration of six phenolic compounds in leaves and twelve compounds in stems were examined using HPLC-DAD and examined in relation to seasonal changes in AGE inhibition activity, assessed with a fluorescence-based assay. A seasonal decline occurred in the concentration of chlorogenic acid, rutin, and quercetin 3-arabinoside in leaves and chlorogenic acid in stems. The concentration of (+)-catechin, and (-)-epicatechin in stems declined within two weeks before rising and fluctuating insignificantly. AGE inhibition activity of leaves was significantly greater at the final compared to the initial collection date whereas the activity of stems did not change significantly. Relative to the leaf extract, the stem was a more potent inhibitor of AGE formation, which could be a result of the unique phytochemistry of stems. Together, these results revealed significant seasonal variation in the phenolic profile and anti-glycation effects of V. angustifolium extracts and indicated late summer as the collection time yielding optimal activity.

The Mechanisms of Inhibition of Advanced Glycation End Products Formation through Polyphenols in Hyperglycemic Condition

“…(Ericaceae)], had the highest antiglycation activity, if the plants were harvested in late summer. Alteration in polyphenol levels during the harvesting period has been shown for some compounds, such as such as chlorogenic acid, rutin, quercetin3-arabinoside, (+)-catechin, and (−)-epicatechin [48]. In a comparative antiglycation study among some bean species, alcoholic extract of mung bean, Vigna radiate (L.) R.Wilczek (Fabaceae), displayed the highest inhibitory activity on AGEs formation due to its higher amount of phenolic compounds known as vitexin and isovitexin [45].…”

Anthocyanins and Flavonoids of Vaccinium L.

“…Basic flavonoid structure. V. bracteatum (leaves) [73][74][75] V. uliginosum (fruit) [66] V. vitis-idaea (fruit) [22] V. intermedium (fruit) [22,48] V. meridionale Swartz (fruit) [47] 47 Quercetin V. angustifolium (fruit) [103,104] V. corymbosum (leaves) [18,46,95] V. koreanum (leaves) [54] V. calycinum (leaves) [53] V. myrtillus (fruit & leaves) [21,22,46] V. reticulatum (leaves) [53] V. smallii (leaves) [72] [49]…”

“…angustifolium (fruit) [103,104] V. virgatum = V. ashei (fruit) [63] V. corymbosum (leaves) [37] V. calycinum (leaves) [53] V. myrtillus (fruit) [21,22,46] V. reticulatum (leaves) [53] V. arctostaphylos (leaves) [58,106] V. smallii (leaves) [49] V. uliginosum (fruit) [23,66] V. vitis-idaea (fruit) [42,70] V. intermedium (fruit) [22,48] V. floribundum (fruit) [68] V. bracteatum (leaves) [51,64] 54…”

“…oxycoccos (fruit) [107] V. quadripetalis (leaves) [108] V. angustifolium (fruit) [103,104] V. corymbosum (leaves) [37] V. darrowii (fruit) [109] V. calycinum (leaves) [53] V. myrtillus (fruit & leaves) [22] V. reticulatum (leaves) [53] V. angustifolium (fruit) [103,104] V. virgatum = V. ashei (fruit) [63] V. corymbosum (leaves) [37,46,95] V. myrtillus (fruit) [21,22,46] V. smallii (leaves) [49] V. bracteatum (leaves) [64] V. vitis-idaea (fruit) [42,70] V. intermedium (fruit) [48] 60 Quertine-3-O-galactoside V. macrocarpon (fruit) [4,69] V. smallii (leaves) [49,72] V. bracteatum (leaves) [64] V. vitis-idaea (fruit) [59,70] V. myrtillus (fruit & leaves) [21,22,46] 61…”

“…vitis-idaea (fruit) [22] V. angustifolium (fruit) [103,104] V. virgatum = V. ashei (fruit) [63] V. corymbosum (leaves) [95] V. darrowii (fruit) [109] V. myrtillus (fruit) [21,62] V. arctostaphylos (leaves) [111] V. uliginosum (fruit) [23,66] V. vitis-idaea (fruit) [70] V. intermedium (fruit) [68] O--L-rhamnoside ( three conjugated components consisting of a flavonol, sugar, and carboxylic acid (benzoic or hydroxycinnamic acids). This is also the first report identifying quercetin-3-arabinoside in both furanose and pyranose forms in cranberry [69].…”