Determination of Carotenoids and their Esters in Fruits of Sea Buckthorn (Hippophae rhamnoides L.) by HPLC‐DAD‐APCI‐MS

Abstract

The berries of Hippophae rhamnoides Linnaeus have high nutritional and medicinal values and have been used for centuries as food both in Europe and Asia. The oleoresins represent a potential source of carotenoid esters and can be used as food additives, cosmetic ingredients or nutraceuticals. The objective of this study was to develop a HPLC-DAD-APCI-MS method, with both positive and negative ionisation modes, for the direct identification of the native carotenoid composition in fruits of Hippophae rhamnoides. Fruits of Hippophae rhamnoides, cv. Serbanesti and Victoria, were collected from an experimental field at the Fruit Research Station of Bacau, Romania. Samples were extracted using methanol:ethyl acetate:petroleum ether (1:1:1, v/v/v). The HPLC-DAD-APCI-MS analyses were carried out on a Shimadzu system using a YMC C₃₀-column and a gradient elution. In total 22 compounds were detected, eight were free carotenoids, nine were xanthophylls monoesters and five were xanthophylls diesters. Differences were observed in the relative percentage composition of the identified components among the two cultivars investigated. Zeaxanthin-C16:0,C16:0 was the most abundant diester. The unsaturated palmitoleic acid was directly detected in its esterified form, in zeaxanthin-C16:0,C16:1, which is reported here for the first time. Although present in small amounts the unsaturated oleic, linoleic, linolenic, hexadecadienoic and hexadecatrienoic acids were detected in their esterified forms as lutein monoesters, the last two having been detected in Hippophae rhamnoides for the first time. A novel (HPLC-DAD-APCI-MS) method was developed for the direct identification of the native carotenoid composition in fruits of Hippophae rhamnoides.