Secondary metabolites from Scrophularia canina L.

A re-examination of Scrophularia canina L. confirmed the presence of iridoid glucosides considered as chemotaxonomic markers for the Scrophulariaceae family, like aucubin, harpagide and 8-O-acetylharpagide, besides the further presence of 8-epiloganic acid, which is, indeed, considered the biogenetic precursor of iridoids normally found in Scrophulariaceae, and was recognised here for the first time in the studied species. Also verbascoside and (E)-phytol were evidenced for the first time in S. canina. The former compound is an almost ubiquitous glycosidic phenyl-ethanoid, which attains systematic importance when in co-occurrence with iridoids, and its taxonomical implications were discussed. The latter compound, even though it is omnipresent, is interestingly endowed with several biological activities, which may give an additional reason for the traditional uses of this plant.

Unusual molecular pattern in Ajugoideae subfamily: the case of Ajuga genevensis L. from Dolomites.

We analysed the ethanolic extract from Ajuga genevensis L. (Lamiaceae) growing in Dolomites, part of Italian Alps. Three new compounds for this species were identified: rosmarinic acid (1), oleanolic acid (2) and maslinic acid (3), representative of two different classes of chemical compounds (phenylpropanoids and pentacyclic triterpenes). A. genevensis resulted to be a valuable source of these compounds endowed with interesting biological activities (i.e. antioxidant, neuroprotective, anti-inflammatory, antiproliferative). The recognition of compounds (1), (2) and (3) may also confirm the ethnomedicinal uses of this plant. From a chemotaxonomical point of view, it is worth noting that iridoids were not evidenced in this accession. Iridoids are considered chemotaxonomic marker in Lamiales, and, in contrast with a previous study on this species, the presence of aucubin was not confirmed. In addition, the presence of large amounts of rosmarinic acid (1) was unexpected for a species that does not belong to subfamily Nepetoideae.

Iridoids from Euphrasia genargentea, a rare Sardinian endemism.

The phytochemical study of Euphrasia genargentea, a rare species only present in Sardinia, led to the identification of iridoid glucosides, i.e. aucubin, catalpol, mussaenosidic acid and melampyroside, which allowed chemotaxonomic considerations on the genus. On the basis of iridoid distribution in the genus, E. genargentea does not show any particular analogy with other Italian Euphrasia spp. This study is also important considering the severe risk of extinction of E. genargentea.

Phenylpropanoid glycosides in Italian Orobanche spp., sect. Orobanche.

We studied the occurrence of phenylpropanoid glycosides (PhG) in five species of the genus Orobanche L., collected in the Latium region of Italy. The presence of orobanchoside and verbascoside in all four species confirms that these PhGs are taxonomic markers of the genus. The results suggest that O. gracilis form. citrina could be a diverse entity.

The occurrence of iridoid glycosides in Cymbalaria spp. in Italy.

The occurrence of iridoid glycosides in a number of Cymbalaria spp. collected in Italy is shown and chemosystematic implications are discussed.

Bis-iridoid glucosides from Abelia chinensis.

Seven bis-iridoid glucosides have been isolated from Abelia chinensis and were characterized by having a secoiridoid residue as unit A esterifying a C(10)-iridoid or a delta-lactone iridoid as unit B. Among these, compounds 1-3 are new and correspond to 7-O-acetyllaciniatoside IV, 7-O-acetyllaciniatoside V, and 7-O-acetylabelioside B, respectively. The structures of 1-3 were elucidated by spectral methods.

An unusual C-skeleton type glucoside from Mentzelia incisa.

A new glucoside with unusual acyclic C13-skeleton has been isolated from Mentzelia incisa Urban et Gilg. The structure was assigned by spectroscopic means.

Production of ochratoxin A by a strain of Aspergillus ochraceus on different seeds

A produçäo de ocratoxina A foi estudada usando-se sementes selecionadas como substrato nutritivo estéril para Aspergillus ochraceus. A produçäo foi maior no girassol do que nas demais sementes examinadas. Dentre os três cultívares de sorgo testados, dois foram altamente resistentes ao ataque do fungo