Determination of Biologically Active Compounds and Antioxidant Capacity In Vitro in Fruit of Small Cranberries (Vaccinium oxycoccos L.) Growing in Natural Habitats in Lithuania

Abstract

The composition of flavonols, proanthocyanidins, anthocyanins, triterpene compounds, and chlorogenic acid in small cranberry fruit samples collected in natural habitats in Lithuania and variation in the antioxidant capacity of cranberry fruit extracts was determined. This study showed that in the flavonol group, hyperoside and myricetin-3-O-galactoside predominated in cranberry fruit samples; in the anthocyanin group, the predominant compounds were cyanidin-3-O-galactoside, cyanidin-3-O-arabinoside, peonidin-3-O-galactoside, and peonidin-3-O-arabinoside, and in the group of triterpene compounds, ursolic acid was predominant. The highest total amounts of flavonols and anthocyanins were found in the samples collected in Čepkeliai State Strict Nature Reserve (2079.44 ± 102.99 μg/g and 6993.79 ± 350.22 μg/g, respectively). Cluster analysis of the chemical composition of small cranberry fruit samples revealed trends in the accumulation of bioactive compounds in cranberry fruit. Cranberry fruit samples collected in central Lithuania had higher levels of triterpene compounds. Statistical correlation analysis showed the strongest correlation between the quantitative composition of cyanidin-3-O-arabinoside and peonidin-3-O-arabinoside and the reducing capacity of the ethanolic extracts of the cranberry fruit samples assessed in vitro by the FRAP assay (r = 0.882, p < 0.01 and r = 0.805, p < 0.01, respectively). Summarizing the results, the geographical factor affects the variation of the quantitative composition of biologically active compounds in cranberry fruit samples.

Keywords: Vaccinium oxycoccos; anthocyanins; antioxidant capacity in vitro; chlorogenic acid; flavonols; natural habitats; proanthocyanidins; triterpene compounds.

Figure 1

The map of small cranberry fruit collection sites.

Figure 2

Total proanthocyanidin content in small cranberry fruit samples collected in natural habitats. Different letters (a–j) indicate statistically significant differences in total proanthocyanidin content between the tested small cranberry fruit samples (p < 0.05).

Figure 3

Variation in the quantitative composition of flavonol compounds in small cranberry fruit samples collected in natural habitats. The different letters indicate statistically significant differences between the values of the total flavonol content in V. oxycoccos fruit samples (a–h, p < 0.05).

Figure 4

Variation in the quantitative composition of chlorogenic acid in small cranberry fruit samples collected in natural habitats. Statistically significant differences in quantitative composition of chlorogenic acid between V. oxycoccos fruit samples are marked with different letters (a–j, p < 0.05).

Figure 5

Variation in the quantitative composition of compounds of the anthocyanin group in small cranberry fruit samples collected in natural habitats. Statistically significant differences in total anthocyanin content between V. oxycoccos fruit samples are marked with different letters (a–h, p < 0.05).

Figure 6

Variation in the quantitative composition of triterpene compounds in small cranberry fruit samples collected in natural habitats. The different letters indicate statistically significant differences between the values of the total amount of triterpenic compounds in V. oxycoccos fruit samples (a–c, p < 0.05).

Figure 7

Hierarchical cluster analysis of small cranberry samples collected in natural habitats: similarity dendrogram based on the amounts of phenolic and triterpene compounds, average compound content in clusters, and distribution of cranberry fruit samples assigned to different clusters in the territory of Lithuania. Different symbols (*/**/*** for anthocyanins, a,b for flavonols, a,b for proanthocyanidins, # for triterpenic compounds) indicate statistically significant differences in the mean content of a group of compounds determined in cranberry fruit samples (p < 0.05).

Figure 8

Variation in the in vitro antioxidant capacity of ethanolic extracts of small cranberry fruit samples collected in natural habitats; different letters (a–g for ABTS and A–I for FRAP) indicate statistically significant differences between the antioxidant capacity estimates of the tested cranberry fruit sample extracts (p < 0.05).