WALA Stiftung

Equisetum arvense L., commonly known as horsetail, is the most prominent Equisetum species and a widely used medicinal plant in traditional and herbal medicine. This study presents a comprehensive phytochemical characterisation of various pharmaceutical extracts prepared from field horsetail according to a national pharmacopoeia, including aqueous fermented extracts, oil-based extracts and hydroalcoholic extracts. Polar constituents were analysed using HPLC-DAD-ESI-MS n. GC-MS analyses following silylation were performed to elucidate low-molecular-weight compounds. The results revealed different phytochemical compositions of the E. arvense L. extracts, with distinct profiles of compounds including hydroxycinnamic acids and flavonoids. The results of the GC-MS investigations indicated the presence of an even broader variety of compounds, comprising benzoic acids, fatty acids, sugars, and phytosterols. Additionally, chlorophyll and carotenoid contents were quantified in the oil-based extracts by UV-VIS spectroscopy. This study underlines the significant impact of the respective extraction parameters on the phytochemical profile of the corresponding pharmaceutical extracts and highlights the rich history and continuing importance of this medicinal plant in traditional and complementary medicine.

Caraway is a widespread agricultural crop that has been utilized by humans since ancient times.It is known as a kitchen spice, medicinal plant in phytotherapy and, due to its high essential oil content, as a fragrant plant and raw material for terpene productionLimonene and carvone, which in turn are used as precursors for the synthesis of further flavorings and fine chems., account for more than 90 % of the essential oil.However, the quality of essential oils can quickly deteriorate due to inadequate storage and by external impacts such as heat, oxygen, and light.In the present study, caraway seeds, caraway essential oil as well as pure standards of limonene and carvone were stored in parallel under real-time conditions at 25 °C and 40 °C to assess the effect of the plant matrix and the natural blend of compounds on essential oil stability.GC and HPLC analyses were used to show that the volatile compounds were well protected in the caraway seeds as no significant changes were determinedIn comparison, a remarkable loss of limonene (22.4 %) due to oxidation-induced alterations was observed for the pure substance, while carvone contents remained almost constant over the entire storage period.The decline of limonene (9.2 %) as part of the essential oil was much lower while carvone again remained unchanged.The formation of novel minor compounds such as limonene-1,2-epoxide, carveol, and limonene-1,2-diol was mainly due to limonene downstream oxidation and increased with elevated storage temperaturesVolatile compunds were best protected in the intact plant seeds, and storage of the entire essential oil is preferable compared with isolated terpenes due to higher stability as representatively demonstrated for the major compound limonene.

Various Achillea species are rich in bioactive compounds and are important medicinal plants in phytotherapy. In the present study, Achillea millefolium L., Achillea moschata Wulfen, and Achillea atrata L. were compared with respect to their phenolic profile and antibacterial activity against gram-positive bacteria strains (Staphylococcus, Propionibacterium). Particular focus was given to A. atrata, which has hardly been studied so far. Based on the metabolite profile, A. atrata exhibited more similarities to A. moschata than to A. millefolium. The former two only differed in the occurrence of four compounds. The flavonols syringetin-3-O-glucoside and mearnsetin-hexoside, not reported for an Achillea species before, have been detected in A. atrata and A. moschata. All Achillea species reduced growth of the tested bacteria. A. atrata demonstrated highest activity against Propionibacterium acnes and Staphylococcus epidermidis, both being involved in the pathogenesis of acne vulgaris. Furthermore, A. atrata has a pronounced anti–methicillin-resistant Staphylococcus aureus potential. Bioassay-guided fractionation revealed that only the most polar fraction of A. moschata displayed antimicrobial activity, which was attributed to phenolics such as apigenin, centaureidin, and nevadensin, being present in high amounts in A. atrata. Thus, this alpine species shows promising antimicrobial activity and might be a potential source for developing novel dermal/topical drugs.