Phenolic Analyses of Haskap Berries (Lonicera caerulea L.): Spectrophotometry Versus High Performance Liquid Chromatography

Haskap berries (Lonicera caerulea L.) are known for their high phenolics, anthocyanins, and antioxidant potential. The data on the phenolic profile of these fruits are lacking. In this study, the phenolic profiles of three haskap varieties; tundra, berry blue, and indigo gem grown in Nova Scotia, Canada were investigated for the first time using spectrophotometery and high-performance liquid chromatography. Berries were analyzed for total phenolic content/total reducing capacity, total anthocyanin content, and antioxidant potential (2,2-diphenyl-1-picrylhydrazyl radical scavenging activity). The total reducing capacity, total anthocyanin content, and 2,2-diphenyl-1-picrylhydrazyl values were 6.17-8.42 mg gallic acid equivalents/gram fresh weight, 4.49-6.97 mg cyanidin-3-glucoside equivalents/gram fresh weight, and 78.70-89.55%, respectively. The extracts were analyzed by reversed-phase diode array detector-high-performance liquid chromatography through a gradient elution using Synergi 4 mu m Max-RP C12 column and the chromatograms were acquired at 520, 360, and 320 nm for athocyanins, flavonoids, and free phenolic acids, respectively. The identified anthocyanins were cyanidin-3-glucoside (82.81-91.99% of the total anthocyanins), cyanidin 3,5-di-glucoside (2.31-4.27%), cyanidin-3-rutinoside (1.54-9.20%), peonidin-3-O-glucoside (0.75-3.44%), and pelargonidin-3-glucoside (0.77-2.98%). Other flavonoids (quercetin-3-beta-D-glucoside and quercetin-3-rutinoside) and free phenolic acids (chlorogenic and neochlorogenic) were also quantified.