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The Marcgraviaceae is a neotropical plant family of lianas and shrubs distributed throughout Central and South America, mainly in evergreen and semi-evergreen tropical forests. In this study, extracts of 12 Marcgraviaceae species were assessed for inhibition of bacterial quorum sensing (QS) in Chromobacterium violaceum, bacterial biofilm formation in Pseudomonas aeruginosa PA14, and fungal growth in Saccharomyces cerevisiae. Six species showed promising inhibitory activities in at least one of the three bioassays (Marcgravia nervosa Triana & Planch., Marcgravia polyantha Delp., Marcgravia schippii Standl., Marcgraviastrum subsessile (Benth.) Bedell, Schwartzia brasiliensis (Choisy) Bedell ex Gir-Canas, and Schwartzia costaricensis (Gilg.) Bedell). Analyses of the crude extract of the leaves of Marcgravia nervosa using HPLC-APCI-MS showed the presence of five pentacyclic triterpenes: ursolic acid (2), betulinic acid (3), [alpha]-amyrin (4), [beta]-amyrin (5), lupeol (6). Bioassay-guided fractionation of this plant resulted in the isolation and identification of 2-methoxy-1,4-naphthoquinone (1) as the active principle with a minimum inhibitory concentration (MIC) of 85-100 [micro]mol x [L.sup.-1] against Saccharomyces cerevisiae BY4741 (haploid) and BY4743 (diploid). Key words: Marcgraviaceae, Marcgravia nervosa, quorum sensing, biofilm, antifungal, naphthoquinone. Les Marcgraviaceae constituent une famille neotropicale de lianes et d'arbustes distribuee a travers l'Amerique Centrale et l'Amerique du Sud, principalement dans les forets tropicales sempervirentes et semi-sempervirentes. Dans cette etude, des extraits de 12 especes de Marcgraviaceae ont ete evalues quant a leur activite inhibitrice de detection de quorum (DQ) bacterien chez Chromobacterium violaceum, de la formation de biofilm chez Pseudomonas aeruginosa PA14 et de la croissance fongique chez Saccharomyces cerevisiae. Six especes ont montre des activites inhibitrices prometteuses dans au moins un des trois essais biologiques (Marcgravia nervosa Triana & Planch., Marcgravia polyantha Delp., Marcgravia schippii Standl., Marcgraviastrum subsessile (Benth.) Bedell, Schwartzia brasiliensis (Choisy) Bedell ex Gir-Canas et Schwartzia costaricensis (Gilg.) Bedell). Des analyses d'extraits bruts de feuilles de Marcgravia nervosa par HPLC-APCI-MS ont montre la presence de cinq triterpenes pentacycliques : l'acide ursolique (2), l'acide betulinique (3), l'[alpha]-amyrine (4), la [beta]-amyrine (5) et le lupeol (6). Le fractionnement de cette plante guide par les essais biologiques a resulte en l'isolement et l'identification de la 2-methoxy-1,4-naphthoquinone (1) comme principe actif possedant une concentration inhibitrice minimale (CIM) de 85-100 [micro]mol x [L.sup.-1] envers Saccharomyces cerevisiae BY4741 (haploide) et BY4743 (diploide). [Traduit par la Redaction] Mots-cles : Marcgraviaceae, Marcgravia nervosa, detection de quorum, biofilm, antifongique, naphthoquinone., Introduction The Marcgraviaceae is a neotropical plant family of lianas and shrubs consisting of seven genera and 130 species distributed throughout Central and South America, mainly in evergreen and semi-evergreen [...]

Microbial biofilms readily form on many surfaces in nature including plant surfaces. In order to coordinate the formation of these biofilms, microorganisms use a cell-to-cell communication system called quorum sensing (QS). As formation of biofilms on vascular plants may not be advantageous to the hosts, plants have developed inhibitors to interfere with these processes. In this mini review, research papers published on plant-derived molecules that have microbial biofilm or quorum sensing inhibition are reviewed with the objectives of determining the biosynthetic classes of active compounds, their biological activity in assays, and their families of occurrence and range. The main findings are the identification of plant phenolics, including benzoates, phenyl propanoids, stilbenes, flavonoids, gallotannins, proanthocyanidins and coumarins as important inhibitors with both activities. Some terpenes including monoterpenes, sesquiterpenes, diterpenes and triterpenes also have anti-QS and anti-biofilm activities. Relatively few alkaloids were reported. Quinones and organosulfur compounds, especially from garlic, were also active. A common feature is the polar nature of these compounds. Phytochemicals with these activities are widespread in Angiosperms in temperate and tropical regions, but gymnosperms, bryophytes and pteridophytes were not represented.