Analysis of bioactive compounds of three sea buckthorn cultivars (Hippophaë rhamnoides L. ‘Askola’, ‘Leikora’, and ‘Orangeveja’) with HPLC and spectrophotometric methods

Abstract

Sea buckthorn (SBT) fruit is rich in biologically active compounds. It has considerable health benefits, thus it can serve as functional food ingredient. The aim of this study was to comprehensively characterize the fruit quality traits of three SBT cultivars (‘Leikora’, ‘Askola’, ‘Orangeveja’) grown in Hungary by determining their physicochemical (refraction, titratable acid content, sugar/acid ratio, carbohydrate profile) and antioxidant parameters (by spectrophotometric methods: FRAP, DPPH, and by HPLC method: Β-carotene content, phenolic compounds). The statistical analysis was made by SPSS 14.0. Univariate analyses were made to separate the homogenous groups using the Duncan test. Significant differences were shown in the refraction of the cultivars (5.6-7.9 °Brix) and in their titratable acid content (2.35-3.07%), but no statistically significant difference has been found in the sugar/acid ratio (2.41-2.57). Glucose (9.56-12.9 mg L -1 ) was the main carbohydrate component of the studied cultivars. In addition to that, we detected fructose (1.39-5.4 mg L -1 ) and mannitol (1.77-9.24 mg L -1 ). The antioxidant state of the studied cultivars could be well-characterized by their TPC (186-381 mg GAS 100 g -1 ), DPPH (60.37-79.1 µg Trolox L -1 ), FRAP (3335-4887 µg AA mL -1 ) and by their Β-carotene content (0.37-0.92 mg mL-1); however no significant correlation was found among these antioxidant parameters. We determined the content of quercetin derivatives in the fruits of the SBT genotypes, such as the rutin (22.12-27.52 mg 100 g -1 ), quercitrin glucoside (50.19-57.72 mg 100 g -1 ), quercetin dihydrate (5.11-6.45 mg 100 g -1 ), quercitrin hydrate (1.59-3.34 mg 100 g -1 ) content, cinnamic acid (78.18-88.93 µg 100 g -1 ) and epicatechin (456.73-488.05 mg 100 g -1 ). We concluded that the antioxidant properties are defined by both the genotype and by the climatic and growing conditions. The fruits of the cultivars ‘Leikora’ and ‘Orangeveja’ can be used as raw material of functional food products, according to their fruit quality traits.