Evaluation of the content and stability of the constituents of mother tinctures and tinctures: the case of Crataegus oxyacantha L. and Hieracium pilosella L.

As a part of our investigations on the content and stability of herbal drug preparations, we evaluated the content and stability of tinctures and mother tinctures of Hawthorn leaves and flowers and Hawkweed. Hawthorn preparations are mainly used by patients with cardiac diseases; Hawkweed is employed for the treatment of cellulitis and obesity due to its diuretic properties. Both tinctures (DER 1:5) and mother tinctures (DER 1:10) are herbal preparations reported in the European Pharmacopoeia. The first preparation is obtained using dried herbal drugs; the latter is a homoeopathic preparation obtained with fresh plant material, often used in substitution of tinctures. The aim of this work was to assess the qualitative and quantitative profile of the constituents of the investigated preparations and the chemical stability of their marker constituents from long-term testing using HPLC assays. Characteristic constituents of Hawthorn leaves and flowers are flavonoids such as vitexin-2''-O-rhamnoside and hyperoside and oligomeric procyanidins. Characteristic constituents of Hawkweed are caffeoyl-quinic acid derivatives, flavonoids and a coumarin:umbelliferone. Our investigation showed that Hawthorn mother tincture had a higher concentration of procyanidins with respect to the tincture but the stability of these constituents were very low in both preparations. Total flavonoidic content was 3.33 mg/ml, about 1.5 times more than the content of mother tincture and the shelf-life t(90) was about 7 months for both preparations. For Hawkweed preparations a content of caffeoyl-quinic acid derivatives (ca. 4 mg/ml) was found, but their stability was good only in the tincture. The concentrations of flavonoids and umbelliferone were two times as much in the tincture with respect to the mother tincture. Stability of these two classes of constituents was good for both preparations over a 9-month period.