Quantification of the main ellagitannins of Hippophaë rhamnoides leaves

Hippophaë rhamnoides L. is a widespread shrub native to various areas in Europe and Asia. Its astringent berries are edible, and especially the berries and leaves have been thoroughly studied, partly because of their alleged medicinal potential [1]. It is known that the leaves are rich in ellagitannins [2] and the main ellagitannins have been identified [3], but publications dealing with the chemical profile of the various plant parts of H. rhamnoides are very often lacking in the accurate characterization of the polyphenolic compounds.

In this study, the ten main ellagitannins of H. rhamnoides leaves were identified and quantified using UHPLC-DAD-Orbitrap-MS and HPLC-DAD instrumentation. A total of 64 plant individuals, covering both sexes and three different cultivars, were analyzed. The main ellagitannins were identified as vescalagin, castalagin, pedunculagin, isostrictinin, stachyurin, casuarinin, elaeagnatin A, pterocarinin A, hippophaenin B and hippophaenin C.

Male plants were found to contain slightly higher total concentrations of ellagitannins compared to female plants with the concentrations averaging at 73.55 mg of ellagitannins per gram dry weight with a true standard deviation of 2.67 mg g^-1, and 70.04 ± 2.68 mg g^-1, respectively. From the three cultivars (R, K and RUXRA), individuals of cultivar R had the highest total ellagitannin content on average (77.92 ± 3.03 mg g^-1) with K and RUXRA sharing similar concentrations (68.46 ± 3.25 mg g^-1 and 69.34 ± 3.79 mg g^-1).

In general, stachyurin, casuarinin and hippophaenin C were the most abundant compounds, and vescalagin and castalagin were detected in the lowest quantities. Little variance was seen in the quantities of individual ellagitannins between the three cultivars, with the clearest exception being elaeagnatin A and hippophaenin B, which were detected in significantly lower quantities in individuals of cultivar K when compared to the other two cultivars.

Acknowledgements: Jukka Konttila is acknowledged for the growing, collection and drying of the plant material.

Keywords: Hippophaë rhamnoides L., ellagitannins.

References:

[1] Suryakumar G, Gupta A. Medicinal and therapeutic potential of Sea buckthorn (Hippophae rhamnoides L.). J Ethnopharmacol 2011; 138: 268 – 278

[2] Moilanen J, Koskinen P, Salminen J-P. Distribution and content of ellagitannins in Finnish plant species. Phytochemistry 2015; 116: 188 – 197

[3] Yoshida T, Tanaka K, Chen X-M, Okuda T. Tannins from Hippophae rhamnoides. Phytochemistry 1991; 30: 663 – 666