A Comparative Study on Essential Oil Intraspecific and Seasonal Variations: Melissa romana Mill. and Melissa officinalis L. from Sardinia

Two species of Melissa are currently present in Sardinia: Melissa officinalis L. and Melissa romana Mill. Our research can only count on a few supported evidences (as reported in Flora Italiana and Moris) and some notes on new stations in Sardinia that give us some information about morphology, distribution, bioecological, and ethnobotanical characteristics of both species. In this paper, we present the results of the research about morphological aspects of M. romana vs. M. officinalis, and their essential oils in different stations at different phenological periods. Moreover, we compared the essential oil of M. romana with the one obtained from M. officinalis growing in the few naturalized stations still present in Sardinia. The most evident morphological differences between the two entities are the long-stalked capitate glandular trichomes, shorts and inclined capitate trichomes, and peltate hairs. The chemical composition of essential oil presents several significant differences between the species. In fact, oils show that in none of the phenological stages, M. romana recalls in its composition M. officinalis. Major distinctions are also evident between dry and fresh plants, and among essential oils distilled in different seasons.

Cardenolides content in wild Sardinian Digitalis purpurea L. populations

In order to quantify the amounts of digitoxigenin and gitoxigenin in wild Sardinian Digitalis purpurea L. an easy extraction method and an high performance liquid chromatography (HPLC) analytical technique have been set up. The analyzed samples, stemming from six different locations, showed a great variability in glycoside content. The HPLC analyses carried out on 2-year-old plants of D. purpurea showed that the amounts of digitoxigenin and gitoxigenin ranged between 11.34 and 240.59 mg kg(-1) and 4.05 and 178.07 mg kg(-1), respectively, calculated on fresh material. Chemometric analyses, carried out considering different morphological characters, showed that correlations between morphological variations and glycoside content are poor.

Phototoxicity due to Cachrys libanotis

After classification and identification of the plant, the alcoholic extract of Cachrys libanotis L. was analysed in order to identify the phototoxic agents. The substances responsible for photodermatitis were found to be 4 furocoumarins, of which 3 have been clearly identified, namely 5-methoxy-, 8-methoxy- and 5,8-dimethoxypsoralen. The structure of a 4th compound was not completely defined.

[Pollinosis caused by Parietaria. Clinical observations in Northern Sardinia and botanical and allergic considerations on P. officinalis L. and P. judaica L. (P. diffusa Mert. and Koch)]

Botanical and allergological relations between two Parietaria species with greater pollinosic incidence, P. officinalis and P. judaica-P. diffusa, are examined: taxonomic and morphological aspects are discussed, and a key for their determination is proposed. Results of clinical-allergological survey on pollinosic subjects in North Sardinia during several years by means of Prick or Scratch Test are now presented. Diagnostic assays have been effected with extracts found on the market while the therapy has been carried out with extracts of "allergoids" and "modified" type, as well as with extracts of P. judaica. Cross-reactivity between P. officinalis and P. judaica has been evidenced, and greater therapeutic efficacy has been observed by employing "purified" and "modified" vaccines.