Variation of Fruits Morphometric Parameters and Iridoid Content of Lonicera caerulea L. Germplasm Collection

Abstract

The dark-blue, fleshy berries of Lonicera caerulea L. are used as fresh or processed in many products such as juice, smoothie, wine, compote, jam, marmalade, candies, chocolate, cake, or extracts. L. caerulea fruits are appreciated in the food industry and medicine mainly due to a high content of biologically active phenolic compounds, especially anthocyanins and vitamin C – in the amount up to 186 mg.100 g^-1, and health-promoting properties. Thirty-four genotypes of Lonicera caerulea species originated from germplasm collection of the Forest-Steppe of Ukraine in M.M. Gryshko National Botanical Garden of NAS of Ukraine (NBG) (Kyiv, Ukraine) and were characterized by using the morphometric traits and iridoids content. Differences between the genotypes were significant in all observed parameters. The fruits of L. caerulea collection varied in evaluated morphometric parameters as follows: fruit weight 0.70–1.54 g, length 15.33–26.52 mm, diameter 7.12–13.10 mm. The shape indexes of fruits varied from 1.42 to 3.65. Our results showed that the content of iridoids ranged from 97 to 314 mg.100 g^-1 of fresh L. caerulea fruits. Interestingly, L. caerulea berries taste differs between the varieties, those with bitter or sour-bitter taste are distinguished by the highest content of iridoids (225–314 mg.100 g^-1), while berries without bitter taste were characterized by significantly lower contents. Thus, honeysuckle berries should be selected preferentially regarding their bitterness, due to the anti-inflammatory and antioxidative properties of iridoids.