Morphology and phytochemistry of Sanguisorba officinalis L. seeds (Rosaceae)

Abstract

Great burnet (Sanguisorba officinalis) has been used as medicinal plant for more than 2000 years. However, little is known about the morphology and the secondary metabolites of its seeds. The investigations reported here focus on the morphology and the characterization of phenolics and fatty acids in S. officinalis seeds. For this purpose, dried seeds were investigated using scanning electron microscopy to clarify their compartment structures. Furthermore, the seeds were extracted with CH2Cl2 and MeOH to characterize the fatty acids and to assess the secondary metabolite profile. The seed structure consists of a floral cup, a brown pericarp with calcium oxalate crystals, a fibre layer and the seed kernel with its seed coat. Individual compounds were characterized by high performance liquid chromatography and gas chromatography coupled with mass spectrometric detection (HPLC-DAD-MSn and GC/MS). CH2Cl2 extraction and GC investigations revealed the occurrence of fatty acids (29% of the seed dry weight), with linoleic acid, linolenic acid, and oleic acid as major compounds. In addition, MeOH extracts were analyzed by LC/MSn, which revealed the occurrence of flavonoids (quercetin, catechin, epicatechin), ellagitannins and caffeic acid derivatives.