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International audience; In our continual course toward the valorization of traditionally used endemic flora through the analysis of its chemobiodiversity, the phytochemical analysis of aerial parts of Marrubium deserti de Noé was undertaken. Dichloromethane and methanol extracts led to the isolation of terpenoid derivatives among which two were new labdane diterpenes named marrulibacetal A and desertine, respectively. Six of them were known compounds (a mixture of the isomers cyllenin A and 15-epi-cyllenin A, marrubiin, marrulactone, marrulibacetal and β-stigmasterol) and seven known phenolic compounds were also isolated: apigenin and several 7-O-substituted derivatives (apigenin-7-O-β-neohesperidoside, apigenin-7-O-glucoside, terniflorin and apigenin-7-O-glucuronide) together with two phenylethanoid glucosides (acteoside and forsythoside B). The structures and relative configurations of the new compounds were elucidated by MS and a series of 1D and 2D NMR analyses. Some pure compounds have been evaluated for their antioxidant activities through different methods: DPPH and ABTS assays as well as CUPRAC assay. Genotoxic and antigenotoxic activities of extracts and pure compounds were also evaluated in vitro on Escherichia coli PQ37 cells by the SOS Chromotest. Some of the isolated compounds like phenylethanoid derivatives showed stronger antioxidant capacity than trolox and were also able to significantly inhibit β-galactosidase induction caused by the mutagen agent nitrofurantoin.

Three taxa have been described to study common junipers of the old world : Juniperus communis L., Juniperus alpina (Suter) Celak and Juniperus hemisphaerica Presl.. Their populations show a large variability and morphological criteria (habit and leaf morphology) do not always make it possible to differenciate between them. Proanthocyanic (prodelphinidin) analysis was performed on 450 specimens to better understand biological diversity within this complex. A multi-criteria approach (morphology, geography, ecology and biochemistry) yielded reference profiles for J, communis (23 specimens), J. alpina (18 specimens) and J. hemisphaerica (19 specimens). These types were used as guidelines for the analysis of populations found in several mountain ranges which showed, depending on the area, introgression processes (J. communis x J. alpina", J. communis x J. hemisphaerica) revealing the originality of either islands (Corsica) or some mountains that function as continental biogeographic islands (Mount Ventoux, Lure Mountain, Apennines). Creeping junipers found in Mediterranean (Sierra Nevada) and peri-Mediterranean (Pyrénées, Massif Central, Mount Ventoux, Southern Alps pro parte) mountains do not generally belong to the «nana» taxon which is restricted to the Alps and some «islands» (Corsica, Apennines). They are fundamentaly linked with the «communis» taxon (sensu stricto) as are Scandinavian and Baltic populations, whatever their habit. The very high biological diversity of Juniperus aggr. communis L. led the authors to discuss the phylogenetic origins of the main taxa and to propose a new biogeographic scheme for their distribution. Hypotheses are made concerning the ecological consequences of the studied populations’ biochemical structuration on strategies for repelling herbivores., Trois taxons ont été décrits pour réunir les genévriers communs de l’Ancien Monde : Juniperus communis L., Juniperus alpina (Suter) Celak, Juniperus hemisphaerica Presl. Leurs populations présentent une grande variabilité et les critères morphologiques (port et feuillage) ne permettent pas toujours de les séparer sans ambiguïté. Pour parvenir à une approche plus complète de la diversité biologique au sein de ce groupe, 450 spécimens ont été soumis à l’analyse proanthocyanique (prodelphinidine). Une approche multicritères (morphologique, géographique, écologique et biochimique) a tout d’abord permis de caractériser les profils référentiels de J. communis (23 spécimens), J. alpina (18 spécimens) et J. hemisphaerica (19 spécimens). Ces types ont ensuite guidé une analyse de populations présentes dans différents massifs montagneux, mettant en évidence selon les secteurs des processus d’introgression (J. communis x J. alpina ; J. communis x J. hemisphaerica ) qui expriment l’originalité des îles (Corse), ou de certains massifs fonctionnant comme des îles biogéographiques continentales (Ventoux, Lure, Apennins). Plus généralement, les genévriers rampants des montagnes méditerranéennes (Sierra Nevada) et péri-méditerranéennes (Pyrénées, Massif Central, Mont Ventoux, Alpes du Sud pro parte ) ne relèvent pas du taxon «nana», restreint aux Alpes et à quelques «îles» (Corse, Apennins) ; ils sont à rattacher fondamentalement au taxon communis (sensu stricto), comme d’ailleurs les populations Scandinaves et baltes, quel qu’en soit le port. La diversité biologique très marquée de Juniperus aggr. communis L. conduit les auteurs à discuter des origines phylogénétiques des principaux taxons, et à construire un nouveau schéma biogéographique de leur répartition. Des hypothèses sont formulées quant aux conséquences écologiques de la structuration biochimique des populations étudiées sur les tactiques de dissuasion des herbivores., Barbero Marcel, Bayet Christine, Hammoud Abdulillah, Laracine-Pittet Claire, Lebreton Philippe. Diversité biologique du Genévrier commun, espèce collective flavoniquement polymorphe. In: Ecologia mediterranea, tome 16,1990. pp. 13-39.

Phytochemical investigation of the leaves of Umbilicus pendulinus afforded in addition to 2-O-caffeoyl malate, isoquercitrin and Z-venusol, the new isomer E-venusol. Special NMR experiments were carried out to elucidate the configuration of the two latter compounds.