Sandra Gallori

Kava-kava and anxiety: Growing knowledge about the efficacy and safety

Kava-kava (Piper methysticum G. Forster) has been used in social and ceremonial life in the Pacific islands from ancient times for the soporific and narcotic effects. Today several extracts standardized in the biologically active constituents kavalactones are marketed both as herbal medicinal products for anxiety disorders and as dietary supplements to improve stress disorders, nervous tension and restlessness. Unlike other substances used for these purposes, kava-kava has been shown to have minimal negative effects, and possibly positive effects, on reaction time and cognitive processing. Furthermore, it decreases anxiety without the loss of mental acuity. Although kava-kava has been found to be very effective, well tolerated, and non-addictive at therapeutic dosages, potential side effects can occur when very high doses are taken for extended periods. In addition, in the last two years unexpected high liver toxicity has been reported in two patients. Until now no studies support the liver toxicity of kavalactones and it is unknown which compound could have provoked the liver disease. On the other hand, it should be possible that unknown or unexpected constituents are the responsible or contributed to the liver toxicity.

Stability of the constituents of Calendula, Milk-thistle and Passionflower tinctures by LC-DAD and LC-MS

As a part of our investigations on the stability of tinctures, we evaluated 40 and 60% v/v tinctures of Calendula flower, Milk-thistle fruit and Passionflower. These preparations are widely employed in phytotherapy, thus Calendula is used externally for anti-inflammatory properties, Milk-thistle and Passionflower are employed for hepatic injuries and in tenseness with difficulty in falling asleep, respectively. Aim of this work was to assess the chemical stability of their active or marker constituents from accelerated and long-term testing by using HPLC. For Calendula flower and Passionflower active constituents are not known, however, flavonoids seem to have a crucial importance for the activity, and thus are considered the markers of Calendula and of Passionflower. Active constituents of Milk-thistle are represented by silymarin that is a phytocomplex mainly constituted by three flavolignans: silybin, silychristin and silydianin. Our investigation showed a very low thermal stability of the constituents from accelerated and long-term testing and determined by HPLC-DAD and -MS analyses and was related both to the class of flavonoids and water content of the investigated tinctures. Thus, shelf-lives at 25 degrees C of the most stable tincture (Passionflower 60% v/v) was about 6 months and only about 3 months the stability of Milk-thistle tinctures.

Variability in the content of the constituents of Hypericum perforatum L. and some commercial extracts

Seven samples of Hypericum perforatum L. (St. Johns wort) were collected throughout Tuscany; the dried extracts were assayed to determine the concentration of the constituents. Total flavonol content ranged from 4.58% to 15.90%; hypericins ranged from 0.05% to 0.11%; and hyperforins ranged from 1.37% to 20.80%. In addition, four commercially dried extracts were analyzed using the same high-performance liquid chromatographic (HPLC) method; their flavonol contents varied from 10.64% to 15.01%, hypericins varied from 0.03% to 0.20%, and hyperforins varied from 1.18% to 6.54%. The aim of this investigation was to evaluate the contents of the different constituents depending on environmental factors and drying and storage conditions of the wild samples. In addition, the contents of the constituents of the products available to the consumer that were related to quality and the relation of this to safety and efficacy were also evaluated.

Optimization of the chromatographic determination of polyphenols in the aerial parts ofCichorium intybus L.

SummaryThe aim of this work was to contribute to the phytochemical characterization ofCichorium intybus L. var.silvestre, chicory. Semi-preparative HPLC analysis was applied to an extract of fresh wild chicory leaves to separate and collect the main polyphenolic compounds.HPLC-diode-array detection (DAD), HPLC-MS, and NMR were used for the complete chemical characterization of all the compounds isolated. The molecules characterized were monocaffeoyl tartaric acid, chicoric acid, monocaffeolyp-hydroxycinnamoyl tartaric acid, caffeoyl feruloyl tartaric acid, chlorogenic acid, quercetin-3-O-glucuronide, luteolin-7-O-glucuronide, and quercetin-3-O-glucoside.The chromatographic behaviour of the main components of the extract of the leaves has been compared on three different stationary phases-LiChrosorb RP18, Luna C18, and Luna Phenyl-Hexyl.

Determination of myricetin derivatives in Chrysobalanus icaco L. (Chrysobalanaceae)

The flavonoidic fraction composition of the hydroalcoholic extract of Chrysobalanus icaco L. (Chrysobalanaceae) leaves, which are largely used in the traditional medicine in Northern Brazil to control the glycaemia of diabetic patients, was characterised. Myricetin 3-O-glucuronide (miricitrin) and quercitrin, among other minor myricetin derivatives, were evidenced by HPLC/DAD and HPLC/MS analysis.

Standardization of Herbal Drugs Derivatives with Special Reference to Brazilian Regulations

The technical standardization of an intermediary of a phytomedicine is a decisive step for the quality standard that the product will show. After the validation of the alleged use, popular form of use, posology and agronomic certification of the plant material, for which phytochemical and pharmacognostic pattern will be developed to monitor the physical, chemical and physico-chemical characteristics of the plant, ensuring homogeneity of samples and the similarity to specimens tested in experimental stage. The plant material is then extracted and the obtained extract is used in the development of the formulation. This extract must be in accordance to the Brazilian Pharmacopoeia, respecting as far as possible the characteristics of the popular form of use. Before the next step, the pharmacotechnical handling, the extract will be phytochemically analysed, in order to determine the metabolic substance classes present in the sample. Then it must be pharmacologically investigated to assure that its activity, is similar to that originally alleged and experimentally tested; its physical and physico-chemical characteristics will be determined, and, subsequently, the extract undergoes chemical and chromatographic analysis to have identified substances that could characterize the plant and serve as chemical and, preferably, pharmacological quality markers. Substances which are chemically stable, responsible for the activity to be presented by the phytomedicine and able to be detectable and quantifiable by usual analytical methods, such as chromatography and ultraviolet spectroscopy or mass spectrometry, are potential candidates to be used as markers.