Phytochemical Investigation of Myrcianthes cisplatensis: Structural Characterization of New p-Coumaroyl Alkylphloroglucinols and Antimicrobial Evaluation against Staphylococcus aureus.

Species of Myrtaceae Juss., the ninth largest family of flowering plants, are a valuable source of bioactive specialized metabolites. A leading position belongs to phloroglucinol derivatives, thanks to their unusual structural features and biological and pharmacological properties. Myrcianthes cisplatensis (Cambess.) O. Berg, a common tree on the banks of rivers and streams of Uruguay, southern Brazil, and northern Argentina, with aromatic leaves, is known as a diuretic, febrifuge, tonic, and good remedy for lung and bronchial diseases. Despite knowledge about traditional use, few data on its phytochemical properties have been reported in the literature. The methanol extract of M. cisplatensis, grown in Arizona, USA, was first partitioned between dichloromethane and water and then with ethyl acetate. The enriched fractions were evaluated using a broth microdilution assay against Staphylococcus aureus ATCC 29213 and 43300 (methicillin-resistant S. aureus (MRSA)). The potential antimicrobial activity seemed to increase in the dichloromethane extract, with a MIC value of 16 µg/mL against both strains. Following a bio-guided approach, chromatographic techniques allowed for isolating three coumarin derivatives, namely endoperoxide G3, catechin, and quercitrin, and four new p-coumaroyl alkylphloroglucinol glucosides, named p-coumaroylmyrciacommulone A-D. Their structures were characterized through spectroscopic techniques: 2D-NMR experiments (HSQC, HMBC, and HSQC-TOCSY) and spectrometric analyses (HR-MS). The antimicrobial assessment of pure compounds against S. aureus ATCC 29213 and ATCC 43300 demonstrated the best activity for p-coumaroylmyrciacommulone C and D with the growth inhibition of 50% at 32 µg/mL against both strains of S. aureus.

The Taming of Psidium guajava: Natural and Cultural History of a Neotropical Fruit.

Guava (Psidium guajava L., Myrtaceae) is a Neotropical fruit that is widely consumed around the world. However, its evolutionary history and domestication process are unknown. Here we examine available ecological, taxonomic, genetic, archeological, and historical evidence about guava. Guava needs full sunlight, warm temperatures, and well-distributed rainfall throughout the year to grow, but tolerates drought. Zoochory and anthropochory are the main forms of dispersal. Guava's phylogenetic relationships with other species of the genus Psidium are unclear. A group of six species that share several morphological characteristics are tentatively accepted as the Psidium guajava complex. DNA analyses are limited to the characterization of crop genetic diversity within localities and do not account for possible evolutionary and domestication scenarios. A significant amount of archeological information exists, with a greater number and older records in South America than in Mesoamerica, where there are also numerous historical records. From this information, we propose that: (1) the guava ancestor may have originated during the Middle or Late Miocene, and the savannas and semi-deciduous forests of South America formed during the Late Pleistocene would have been the most appropriate ecosystems for its growth, (2) the megafauna were important dispersers for guava, (3) dispersal by humans during the Holocene expanded guava's geographic range, including to the southwestern Amazonian lowlands, (4) where its domestication may have started, and (5) with the European conquest of the Neotropics, accompanied by their domestic animals, new contact routes between previously remote guava populations were established. These proposals could direct future research on the evolutionary and domestication process of guava.

Componentes volátiles de las hojas de Pimenta racemosa var racemosa(Mill. ) JW Moore (Myrtaceae) de Táchira – Venezuela / Volatile compounds of Pimenta racemosa var racemosa (Mill. ) JW Moore (Myrtaceae) leaves from Táchira-Venezuela

Pimenta racemosa var. racemosa (Mill.) J.W. Moore, is a Caribbean arboreal plant belonging to the family Myrtaceae with a special interest in their leaves for the production of essential oil, commonly known as "Bay-Rum". Steam distillation of fresh leaves collected in April 2012 produced two types of essential oil, one of these resulted lighter than water and was named (AL) and the other one heavier than water (AP). Gas chromatography/mass spectrometry analysis showed the presence of 17 components constituting 99.9 percent for AL, being the major compounds: eugenol (60.4 percent), myrcene (11.7 percent), chavicol (6.0 percent), limonene (5.4 percent) and linalool (4.4 percent); for the AP, 13components were identified (98.3 percent) from which eugenol (82.9 percent) and chavicol (9.3 percent) were in major proportions.

Pimenta racemosa var. racemosa (Mill.) J.W. Moore, es una planta caribeña, arbórea, perteneciente a la familia Myrtaceae y con un especial interés en sus hojas para la producción del aceite esencial comúnmente conocido como “Bay-Rum”. La destilación por arrastrecon vapor de las hojas frescas colectadas en abril 2012 produjo dos tipos de aceites esenciales, uno ligero (AL) y otro más pesado que elagua (AP). El análisis de sus componentes volátiles por cromatografía de gases/espectrometría de masas mostró 17 componentes lo que constituye el 99,9 por ciento del AL de los cuales los mayoritarios fueron eugenol (60,4 por ciento), mirceno (11,7 por ciento), chavicol (6,0 por ciento), limoneno (5,4 por ciento) ylinalool (4,4 por ciento); para el AP, 13 componentes fueron identificados (98,3 por ciento) de los cuales eugenol (82,9 por ciento) y chavicol (9,3 por ciento) fueron los mayoritarios.

Phylogenetic relationships in Myrceugenia (Myrtaceae) based on plastid and nuclear DNA sequences.

Myrceugenia is a genus endemic to South America with a disjunct distribution: 12 species occurring mainly in central Chile and approximately 25 in southeastern Brazil. Relationships are reconstructed within Myrceugenia from four plastid markers (partial trnK-matK, rpl32-trnL, trnQ-5'rps16 and rpl16) and two ribosomal nuclear regions (ETS and ITS) using maximum parsimony and Bayesian analyses. Relationships inferred previously from morphological data are not completely consistent with those from molecular data. All molecular analyses support the hypothesis that Myrceugenia is monophyletic, except for M. fernadeziana that falls outside the genus. Chilean species and Brazilian species form two separate lineages. Chilean species form three early diverging clades, whereas Brazilian species are a strongly supported monophyletic group in a terminal position. Least average evolutionary divergence, low resolution, short branches, and high species diversity found in the Brazilian clade suggest rapid radiation. Geographical distributions and phylogenetic reconstructions suggest that extant Myrceugenia species arose in northern Chile followed by colonization southward and finally to the Juan Fernández Islands and southeastern Brazil.

Taxonomic and phytogeographic implications from ITS phylogeny in Berberis (Berberidaceae).

A phylogeny based on the internal transcribed spacer (ITS) sequences from 79 taxa representing much of the diversity of Berberis L. (four major groups and 22 sections) was constructed for the first time. The phylogeny was basically congruent with the previous classification schemes at higher taxonomic levels, such as groups and subgroups. A notable exception is the non-monophyly of the group Occidentales of compound-leaved Berberis (previously separated as Mahonia). At lower levels, however, most of previous sections and subsections were not evident especially in simple-leaved Berberis. Possible relationship between section Horridae (group Occidentales) and the simple-leaved Berberis clade implies paraphyly of the compound-leaved Berberis. A well-known South America-Old World (mainly Asia) disjunctive distribution pattern of the simple-leaved Berberis is explained by a vicariance event occurring in the Cretaceous period. The ITS phylogeny also suggests that a possible connection between the Asian and South American groups through the North American species ( Berberis canadensis or B. fendleri) is highly unlikely.