Comparative Analysis of Phenolic Compounds in Seven Hypericum Species and Their Antioxidant Properties

A comparative analysis of the phenolic compounds in the 70% EtOH extracts of Hypericum acutum, H. androsaemum, H. barbatum, H. hirsutum, H. maculatum, and H. richeri has been carried out using high-performance liquid chromatography coupled with photodiode array UV detection and high resolution TOF mass spectrometry. Quercetin, astilbin, I3, II8-biapigenin, orientin, 2”- O-acetylorientin, three phenolcarboxylic acids, and eight flavonols 3- O-glycosides were identified in the extracts on the basis of their on-line UV spectra, accurate mass spectral data, and in comparison of retention times with those from the standards. Fingerprint analysis of the extracts revealed significant differences in the qualitative and quantitative chemical composition of the studied species. Antioxidant assays with various reaction mechanisms were used including ferric reducing antioxidant power (FRAP) assay, DPPH, ABTS, superoxide anion radical scavenging capacity and inhibition of liposome peroxidation induced by Fe2+. The most potent were extracts of H. acutum and H. maculatum indicating this Hypericum species interesting for further research aimed as a potentially new source of biologically active compounds.

Environmental Factors do not Affect the Phenolic Profile of Hypericum perforatum Growing Wild in Bosnia and Herzegovina

Using appropriate isolation and fractionation procedure, and UHPLC-MS/MS as powerful analytical tool, comprehensive phenolic acid profile of leaves and flowers of Hypericum perforatum L., growing wild in Bosnia and Herzegovina, has been analyzed for the first time. The phenolic acids were isolated from plant tissue, liberated from esters and glycosidic bonds, and then analyzed as free acids. Results show that free forms of caffeic and chlorogenic acid were the most abundant. Generally, the content of acids is higher in flowers than in leaves, but environmental factors do not significantly influence chemical composition of this medicinal plant.

Chemical Composition of Hypericum richeri subsp. grisebachii Essential Oil from Croatia

The aerial parts of Hypericum richeri Vill. subsp. grisebachii (Boiss.) Nyman were collected from two different locations in Croatia and subjected to hydrodistillation. GC/FID and GC/MS analysis of the isolated essential oils revealed 64 compounds representing 94.7% and 98.2% of the total oils. Predominant constituents in both samples were: germacrene D (10.9%; 6.0%), bicyclogermacrene (4.7%; 3.5%), α-pinene (6.8%; 6.9%), β-pinene (8.1%; 5.1%), decanoic acid (4.5%; 6.8%), β-caryophyllene (3.3%; 7.5%), δ-cadinene (7.0%; 4.4%), spathulenol (6.0%; 9.5%) and tetracosane (3.1%; 5.8%). Comparison of both samples revealed similarity in the chemical composition with minor fluctuations of constituent percentages. The chemical profile of Croatian oils was in general similar to those reported for other geographic areas regarding major mono- and sesquiterpene constituents. However, spathulenol, 5-cadinene and bicyclogermacrene were more abundant in Croatian oils. The presence of decanoic acid (4.5%; 6.8%) in Croatian oils was the major difference between acids and fatty acids derivatives. Higher abundance of alkanes (particularly tetracosane and docosane) was also noticed.