Lipid and Phenolic Constituents from Seeds of Hypericum perforatum L. and Hypericum tetrapterum Fr. and their Antioxidant Activity

Abstract

Seeds of Hypericum perforatum and H. tetrapterum were extracted with dichloromethane and methanol and investigated by chromatographic and mass spectrometric methods. Both species yielded a fatty oil fraction amounting to 30.5% and 18.0% of the seed weight, respectively. Linoleic acid (C18:2n-6) was shown to be the predominant fatty acid constituent. Moreover, xanthone derivatives, i.e. tetrahydroxyxanthones (THX), xanthone-glycosides and xanthone-sulfonates, were assigned in methanolic extracts. For structure elucidation, one representative xanthone, namely 1,3,6,7-THX, was synthesized and analyzed via HPLC-DAD/MS and GC/MS. Total THX contents were quantitated applying a validated HPLC-DAD method, resulting in 1.25 g/kg (H. perforatum) and 0.27 g/kg (H. tetrapterum), respectively. Moreover, the free radical scavenging capacity of the methanol extracts was tested using the DPPH antioxidant assay. Both, H. perforatum (IC = 8.7 mg/l) and 1,3,6,7-THX (IC = 3.0 mg/l), exhibited good DPPH free radical scavenging activity compared to Trolox (IC = 6.6 mg/l).

Structure Elucidation of the Main Tetrahydroxyxanthones ofHypericumSeeds and Investigations into the Testa Structure

“…HPLC and LC/MS have been proven to be best techniques for separation, identification and quantification of naturally occurring xanthones. For qualitative and quantitative analysis of THX X1 and X2 , a reversed‐phase HPLC method, previously published by Heinrich et al, was applied. This method is suitable for the separation of a wide range of xanthone derivatives from Hypericum seeds and covers a broad spectrum of different polarities.…”

“…Characteristic losses of 30, 28 and 44 Da (loss of HCOH, CO and CO 2 , respectively) in collision‐induced dissociation experiments resulted in fragment ions at m/z 229, 201 and 187 ( Figure ,d, e ). These LC/MS data were similar to our previously published data . Finally, H .…”

“…tetrapterum FR.) . Besides fatty oil (CH 2 Cl 2 extract), a MeOH fraction was recovered from Hypericum seeds, being characterized by high content of numerous xanthones, with different functional groups and substitution patterns.…”

“…Besides fatty oil (CH 2 Cl 2 extract), a MeOH fraction was recovered from Hypericum seeds, being characterized by high content of numerous xanthones, with different functional groups and substitution patterns. By means of HPLC‐DAD/MS n and GC/MS xanthone structures with hydroxy, methoxy and sulfonate groups, as well as glycosidic substitution were detected . Among these, two tetrahydroxyxanthones (THX, X1 and X2 ) were analyzed as main constituents of the seeds of both Hypericum species ( H .…”

Characterization of Secondary Metabolites in Flowers of Sanguisorba officinalisL. by HPLC‐DAD‐MSn and GC/MS

“…Aliquots of 10 μL of this test solution were mixed with 170 μL of TBME followed by 60 μL of TMSH. Subsequently, the mixture was directly injected into the GC/MS system …”