Volatile Constituents from Baccharis spp. L. (Asteraceae): Chemical Support for the Conservation of Threatened Species in Uruguay

Chemical bioprospecting is an important tool for generating knowledge regarding local human‐threatened floras and for conservation management. For Baccharis L. (Asteraceae), several volatile components have been reported for Brazil, Argentina, Bolivia, and Chile as a result of bioprospection, but not for Uruguayan flora, which is composed of more than 50 native species. In this work, through collection of aerial parts of different species and volatile simultaneous‐distillation extraction and gas chromatography‐mass spectrometry analyses, twelve native species of Baccharis were studied (B. articulata, B. cultrata, B. genistifolia, B. gibertii, B. gnaphalioides, B. ochracea, B. phyteumoides, B. punctulata, B. crispa, B. dracunculifolia, B. linearifolia subsp. linearifolia, and B. spicata). A detailed analysis of the male and female volatile composition was conducted for the last four species. The profiles of B. cultrata, B. genistifolia, B. gibertii, and B. gnaphalioides are reported for the first time. Because half of the species analyzed in this work are in Uruguay and are threatened or potentially threatened by human economic activities, the importance of their conservation as natural, sustainable resources is highlighted.     

Chemical composition, seasonal variation, and biosynthetic considerations of essential oils from Baccharis microdonta and B. elaeagnoides (Asteraceae)

The chemical composition and seasonal variation throughout one year of the essential oils from leaves of Baccharis microdonta and B. elaeagnoides, collected in Campos do Jordão, SP, were investigated. The composition of the latter species has been described for the first time. By GC (RI) and GC/MS analysis, 43 compounds were identified, and a predominance of oxygenated sesquiterpene derivatives was found in both species. The main components of the B. microdonta oils were elemol ( 31 ; 11.7–30.6%), spathulenol ( 34 ; 4.7–9.1%), β‐caryophyllene ( 19 ; 3.7–6.2%), and germacrene D ( 24 ; 2.9–12.2%), and those of the B. elaeagnoides oils were 34 (10.1–21.5%), viridiflorol ( 35 ; 3.6–18.4%), 24 (0.9–13.8%), and 19 (3.5–9.4%). The identified compounds were grouped according to their respective C‐skeletons, and the percentages of occurrence of the C‐skeletons in the essential oils of leaves collected in the four seasons allowed identifying the preferential accumulation of different types of C‐skeletons as well as the seasonal variation of the biosynthetic routes over the studied period.     

Recent Findings in the Chemistry of Odorants from Four Baccharis Species and Their Impact as Chemical Markers

Baccharis is a widespread genus belonging to the Asteraceae family that includes almost 400 species exclusively from the Americas. Even when studied in detail, the taxonomic classification among species from this genus is not yet fully defined. Within the framework of our study of the volatile composition of the Baccharis genus, four species (B. trimera, B. milleflora, B. tridentata, and B. uncinella) were collected from the ‘Campos de Cima da Serra’ highlands of the Brazilian state of Rio Grande do Sul. The aerial parts were dried and extracted by the simultaneous distillation extraction (SDE) procedure. This is the first time that SDE has been applied to obtain and compare the volatile‐extract composition in the Baccharis genus. Characterization of the volatile extracts allowed the identification of 180 peaks with many coeluting components; these latter being detailed for the first time for this genus. The multivariate statistical analyses allowed separating the volatile extracts of the four populations of Baccharis into two separate groups. The first one included the B. milleflora, B. trimera, and B. uncinella volatile extracts. The three species showed a high degree of similarity in their volatile composition, which was characterized by the presence of high contents of sesquiterpene compounds, in particular of spathulenol. The second group comprised the extract of B. tridentata, which contained α‐pinene, β‐pinene, limonene, and (E)‐β‐ocimene in high amounts.     

Host-specificity of fiveAnacassis species [Col.: Chrysomelidae] introduced into australia for the biological control ofBaccharis halimifolia [Compositae]

Foliage-feeding beetles of the genusAnacassis [A. phaeopoda Buzzi,A. fuscata (Klug),A. fuscata var.unicolor (Burmeister),A. cribrum (Klug) andA. dubia (Boheman)] were collected fromBaccharis spp. andBaccharidastrum spp. in South America. Specificity studies showed that they were restricted to these 2 host genera. Between 1974 and 1976 these species were introduced into Australia for the control ofBaccharis halimifolia. A. phaeopoda andA. fuscata were first released in 1976. One field colony ofA. fuscata persisted for up to 3 years but no recoveries ofA. phaeopoda were made after the 1st field generation. The other species died out in quarantine and were not released.      

Chemical,Antioxidant, and Antimicrobial Evaluation of Essential Oils and an Anatomical Study of the Aerial Parts from Baccharis Species (Asteraceae)

The aim of this study was to evaluate the chemical, antioxidant, and antimicrobial activity of the essential oils as well as the anatomy of the aerial parts from Baccharis aracatubaensis, Baccharis burchellii, and Baccharis organensis owing to the therapeutic potential of Baccharis. The volatile constituents were analyzed using GC/MS, the antioxidant activity was evaluated by oxygen radical absorbance capacity (ORAC_FL) and DPPH assays, and the antimicrobial activity by a microdilution technique. Of the 56 compounds identified, only seven (β‐caryophyllene, γ‐muurolene, bicyclogermacrene, β‐germacrene, spathulenol, τ‐muurolol, and α‐cadinol) were common in the three specimens studied. Of these, γ‐muurolene was found abundantly in B. aracatubaensis, while bicyclogermacrene was abundant in B. burchellii and B. organensis. The essential oils exhibited antioxidant activity in the ORAC_FL (>500.0 μmol TE g^?1) and DPPH assays. However, they did not exhibit any antimicrobial activity. Secretory ducts and flagelliform glandular trichomes were observed in the anatomical study of all the Baccharis species studied.     

Host-specificity and biology ofMetallactus patagonicus [Col.: Chrysomelidae] introduced into Australia for the biological control ofBaccharis halimifolia [Compositae]

Biology and host-specificity of the foliage-feeding chrysomelidMetallactus patagonicus Suffrian were studied in Brazil to determine its suitability for introduction into Australia to control the shrubBaccharis halimifolia L. Multiple-choice host preference testing of plants related toBaccharis and of desirable plants from a range of plant families, showed thatM. patagonicus was restricted toBaccharis spp. It was released in Australia in 1975, but did not establish.      

Control of shrub establishment by springtime soil water availability in an annual grassland

Summary Previous studies have shown that the shrub, Baccharis pilularis spp. consanguinea, invades annual grasslands in the San Francisco Bay region in a sporadic manner. Invasion was shown to be positively correlated with the amount of rainfall received in the spring. Here we show that, although Baccharis seeds are dispersed near the beginning of the winter rainy season, seedling root growth is extremely slow until spring. At this time, cessation of the winter rains and transpiration by the grassland annuals results in drying of the upper soil profile. We conclude that establishment of Baccharis seedlings at our study site usually fails because seedling roots cannot reach depths of permanently moist soil, below the depth of the grass roots, before this soil drought occurs. The continuation of rains into the warmer spring months provides a window of time when favorable temperatures and adequate soil moisture allow shrubs to establish.     

Antiprotozoal,Schistosomicidal, and Antimicrobial Activities of the Essential Oil from the Leaves of Baccharis dracunculifolia

Baccharis dracunculifolia DC. (Asteraceae), popularly known as ‘alecrim do campo’, is a native plant from Brazil used in folk medicine as febrifuge, anti‐inflammatory, antiseptic, and to treat skin sores. Also, B. dracunculifolia is the most important plant source of the Brazilian green propolis, which is recognized for its antiseptic and antiprotozoal activities. This study aimed at investigating the in vitro antiprotozoal, schistosomicidal, and antimicrobial activities of the essential oil from the leaves of B. dracunculifolia. The essential oil was obtained by hydrodistillation and analyzed by GC and GC/MS, which allowed the identification of 14 compounds, mainly oxygenated sesquiterpenes, such as (E)‐nerolidol (33.51%) and spathulenol (16.24%). The essential oil showed activity against promastigote forms of Leishmania donovani, with IC₅₀ values of 42 μg/ml. The essential oil displayed high activity in the schistosomicidal assay, since all pairs of Schistosoma mansoni adult worms were dead after incubation with the essential oil (10, 50, and 100 μg/ml). B. dracunculifolia essential oil was neither cytotoxic against Vero cells, nor active in the antimicrobial and antiplasmodial assays.     

<Emphasis Type="Italic">Baccharis sphagnophila</Emphasis>, a new species of <Emphasis Type="Italic">Baccharis</Emphasis> sect. <Emphasis Type="Italic">Caulopterae</Emphasis> (Compositae: Astereae) from the highlands of Southern Brazil

A new species of Baccharis L. sect. Caulopterae DC. (Compositae) of the high altitude grasslands of Southern Brazil is presented: Baccharis sphagnophila A. A. Schneid. & G. Heiden. The new species is described, illustrated and compared with similar species.     

Baccharis spicata (Asteraceae), a new potentially invasive species to Europe

Baccharis spicata, a species native to South America (southern Brazil, Paraguay, Uruguay, and northeastern and central Argentina) is reported for the first time from Europe. In September 2015, two naturalized populations were detected in the surroundings of Porto (Matosinhos and Vila do Conde) in Portugal. Based on literature data, the species’ taxonomy and nomenclature are analyzed and it is described and illustrated. Furthermore, its ecology, habitat, biology, and possible vector of introduction are discussed. Finally, its invasive potential for the European Union is assessed, based on climatic variables and two different risk assessment methods.     

Shrub establishment under experimental global changes in a California grassland

Accelerating invasion of grasslands by woody species is a widespread global phenomenon. The native shrub Baccharis pilularis has recently increased in abundance in some California grasslands, with large local community and ecosystem effects. I investigated potential contributions of (1) future global climate and atmospheric changes and (2) variation in moisture and nutrient availability to increased Baccharis germination and early establishment rates. I examined responses of Baccharis seeds and seedlings to simulated warming (+ 1−2 °C) and elevated CO₂ (+ 300 ppm) in a 2-year field experiment. Warming and CO₂ treatments were applied at ambient and increased water and nitrogen levels chosen to simulate future increases in precipitation (+ 50%) and N deposition (+ 7 gN m⁻² y⁻¹). Elevated CO₂ and water addition each increased or accelerated germination. Herbivory strongly reduced seedling populations during the winter wet season; drought further reduced seedling survival in the spring. Overall Baccharis survivorship was extremely low (<0.1%) across all treatments, complicating the interpretation of global change effects.     

A new dwarf shrubby species of <Emphasis Type="Italic">Baccharis</Emphasis> subg. <Emphasis Type="Italic">Baccharis</Emphasis> (Asteraceae,Astereae) from southeastern Brazil

Baccharis dichotoma, a new dwarf shrubby species, with small leaves and few heads, of high-altitude grasslands from southeastern Brazil, is described, illustrated, and assigned to subgenus Baccharis.     

Inhibition of doxorubicin-induced mutagenicity by Baccharis dracunculifolia

Baccharis dracunculifolia DC (Asteraceae), a native plant from Brazil, have been used as an antipyretic, stomachic and health tonic in Brazil. The objective of the present study was to investigate the potential mutagenic effect of B. dracunculifolia ethyl acetate extract (Bd-EAE) and its influence on the mutagenicity induced by the chemotherapeutic agent doxorubicin (DXR) using the rat bone marrow and peripheral blood micronucleus test. Wistar rats were divided into 10 treatment groups. Five groups received DXR (90 mg/kg body weight, b.w., intraperitoneally) to induce mutagenicity and three of these groups received a single oral dose of Bd-EAE at a concentration of 6, 12 or 24 mg/kg b.w. prior to DXR administration. A vehicle-treated control group and Bd-EAE control groups were also included. The results showed that Bd-EAE itself was not mutagenic, in the rat micronucleus assay. In animals treated with Bd-EAE and DXR, the number of MNPCEs was significantly decreased compared to animals receiving DXR alone. HPLC analysis of the extract obtained permitted the identification of the following phenolic compounds: caffeic acid, p-coumaric acid, aromadendrin-4′O-methyl ether, 3-prenyl-p-coumaric acid (drupanin), 3,5-diprenyl-p-coumaric acid (artepillin C) and baccharin. The putative antioxidant activity or the interference of one or more of the active compounds of Bd-EAE with mutagenic metabolic pathways may explain its effect on DXR mutagenicity.     

Pollen analysis of honeys from the central zone of the Argentine province of Entre Ríos

Based on the melissopalynology 38 honey samples collected in the central region of the Argentine province of Entre Ríos were classified by botanical and geographical origin. According to qualitative analysis, 20 honey samples were monofloral and 18 were multifloral. Dominant pollen types were Scutia buxifolia Reissek (Rhamnaceae) in six samples, Baccharis spp. (Asteraceae) in five, Lotus spp. (Fabaceae) in three, Eucalyptus spp. (Myrtaceae) and Eryngium spp. (Apiaceae) in two, Ammi visnaga (L.) Lam. (Apiaceae) and Trithrinax campestris (Burmeist.) Drude & Griseb. (Arecaceae) in one sample. One hundred and nineteen pollen types were identified belonging to 52 families; 75% of which were native species. The families best represented in number of species were Asteraceae and Fabaceae. Pollen types such as Scutia buxifolia, Trithrinax campestris, Schinus spp. (Anacardiaceae), Mimosoideae from Prosopis spp., Acacia spp., Mimosa ostenii Speg. ex Burkart, and M. strigillosa Torr. & A. Gray are considered the indicators for this geographical origin. The studied honeys were also characterized by a high frequency of Apiaceae, Brassicaceae, Astereae, Echium plantagineum L. and cultivated Papilionoideae forage species such as Melilotus albus Desr., Lotus spp. and Trifolium spp. Honeydew elements were scarce.     

Host plant effects on the development and survivorship of the galling insect Neopelma baccharidis (Homoptera: Psyllidae)

In this study, the mortality factors acting upon the galling psyllid Neopelma baccharidis Burckhardt (Homoptera) caused by its host plant, Baccharis dracunculifolia De Candole (Asteraceae) were analysed. In March 1999, 982 galls of the same cohort were randomly marked on 109 individuals of B. dracunculifolia in the field. Galls were censused each month during their development, from April to August, and dead galls were collected and analysed for mortality factors. Gall dehiscence rates were calculated for each month. The major mortality source of N. baccharidis was gall dropping (13.2% of the original cohort), which is probably a normal outcome of previous mortality caused by the other factors observed in this study. Unknown factors killed 11.7% of this gall population and were ascribed to plant resistance during gall development. Empty galls represented 7.7% of the observed mortality and may be a consequence of egg retention or egg mortality/abortion related to variations in plant quality. Shoot mortality was high during the dry season and killed 7.5% of the galls, but this impact was minimized after the third month from gall formation due to the ability of nymphs to accelerate development and emerge from galls on dying shoots. However, the size of dehisced galls on dead shoots tended to be smaller, possibly affecting adult performance. Mortality of N. baccharidis attributed to B. dracunculifolia strongly controlled the galling insect population, killing 40.7% of the original cohort of galls. Plant‐mediated mortality was caused by often neglected factors acting predominantly during the first 3 months of development, which are critical to gall survivorship. These results reinforce the importance of bottom‐up forces in plant‐insect systems.     

Characterization of three sect. Caulopterae species (Baccharis-Asteraceae) inferred from morphoanatomy, polypeptide profiles and spectrophotometry data

There are still controversies regarding differentiation between Baccharis species (sect. Caulopterae). In the present work, we compare three species: Baccharis articulata, Baccharis gaudichaudiana and Baccharis trimera, emphasising the importance of anatomy, polypeptide profiles and ultraviolet–visible spectrophotometry as taxonomic characters, utilizing multivariate analysis. Seventy-two populations of the three species were examined. The first two principal components of morphoanatomical data gathered relevant information to classify species (61% of the total variability), with the largest contribution from the stomata density variable (2.105). PCoorA based on protein analysis enabled separation of the species with the first two principal coordinates (67.20% of the total variability). Regarding spectrophotometrical data, the second and third principal components only separated B. trimera from the rest (22.7% of total variability).     

Fire responses of three co-occurring Asteraceae shrubs in a temperate savanna in South America

South American temperate savannas have undergone significant woody plant encroachment through changes in their disturbance regimes. We studied fire strategies and the spatial variation in individual fire responses of Eupatorium buniifolium, Baccharis medullosa and B. dracunculifolia, the dominant shrub species at El Palmar National Park, in areas with different fire history. In recently burnt sites, all Baccharis dracunculifolia individuals died, whereas all E. buniifolium and B. medullosa individuals sprouted. The relative growth rate was higher in E. buniifolium, which invested more biomass in shoots, and in B. medullosa, which invested more biomass in leaves. At the unburnt site, B. dracunculifolia showed the highest growth rate and leaf biomass. B. medullosa produced capitula immediately after fire, whereas E. buniifolium reproduction was delayed for 1 year. In both species, production of capitula and reproductive effort were higher in recently burnt sites. For B. dracunculifolia, production of capitula was lower and the reproductive effort was higher in burnt than in unburnt sites. Seedling establishment was extremely low for E. buniifolium, low for B. medullosa and high for B. dracunculifolia in both recently burnt sites. E. buniifolium behaved as a sprouter, B. medullosa as facultative sprouter and B. dracunculifolia as obligate seeder species. In order to control the increase and/or attain desirable population levels of these species, fire management practices in these savannas should consider individual species’ responses, particularly to the time since the last fire.     

Community changes following shrub invasion of grassland

Summary We studied the development of the shrub Baccharis pilularis ssp consanguinea and its effects on herbs of the annual grassland in Northern California. A series of shands of Baccharis was sampled of ages ranging from 1 yr to>9 yr, representing most of the life cycle of the shrub. In each stand we examined shrub biomass, structure and litterfall. We also determined cover and biomass of all herbaceous species and estimated seed production, seed rain and storage of seed in the soil. Abundances of all herbaceous species declined greatly after Baccharis formed a closed canopy at 2–3 yr, and little seed of herbaceous species was either dispersed into shrub stands or stored in the soil. Exclosures suggested that herbivory by small mammals in the closed shrub stands may be important in reducing the abundance of herbaceous species following shrub invasion of grassland.     

Vigour of a dioecious shrub and attack by a galling herbivore

1. The pattern of attack by the leaf‐galling insect Neopelma baccharidis (Homoptera: Psyllidae) was studied in three populations of the dioecious shrub Baccharis dracunculifolia (Asteraceae) in south‐eastern Brazil. The plant vigour hypothesis, which predicts higher rates of attack and increased herbivore performance on the longest plant shoots, was tested. This work also provides further information for the study of differential herbivory in dioecious plants. 2. In total, 9200 shoots were collected randomly from 46 male and 47 female plants belonging to the three populations. Shoot length, number of leaves per shoot, rate of galling, and survival of psyllids did not differ between male and female plants. Another population on the Campus of the Federal University of Minas Gerais was used only to determine the pattern of shoot growth. 3. The hypothesis of sex‐mediated herbivory was not corroborated in this study. 4. The frequency of galling increased with increasing shoot length, as predicted by the plant vigour hypothesis. Nevertheless, the number of oviposition sites (leaf buds) increased with shoot length. 5. The performance of the galling herbivore was not related to shoot length in the plant populations studied. 6. In conclusion, Neopelma baccharidis did not select shoots based on length only.     

Using wild plant species as indicators for the accumulation of emissions from a thermal power plant, Candiota, South Brazil

The impact of Candiota coal-fired thermal power plant on air quality was evaluated during two years by means of passive biomonitoring. The monitoring consisted of the quarterly collection of leaf samples of Baccharis dracunculifolia, Elephantopus mollis, Eryngium horridum, Paspalum notatum and Piptochaetium montevidense or the shoot of Baccharis trimera at five sites located in the area around the power plant. The element load of these plants was used as indicator for atmospheric pollution. In the samples collected, sulphur and heavy metal cadmium contents were measured. Among the species evaluated, E. mollis presented the highest potential to accumulate metal, followed by B. trimera. The Aeroporto and AFUCAN sampling sites, located in the prevailing wind directions, presented the highest level of metal contamination.