Studies on the constituents from the aerial part of Baccharis dracunculifolia DC. II. (1/30)

Ten new glycosides were obtained along with five known compounds from the aerial part of Baccharis dracunculifolia DC. (Compositae). The structures of these glycosides were determined based on spectral and chemical evidence. These new compounds consisted of beta-D-glucopyranose or beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranose, and most possessed an (E)-caffeoyl group the same as dracunculifosides A-J.  (+info)

Screening of South American plants against human immunodeficiency virus: preliminary fractionation of aqueous extract from Baccharis trinervis. (2/30)

Ethanolic and aqueous extracts of 14 South American medicinal plants were tested for inhibitory activity on human immunodeficiency virus (HIV). Both extracts were relatively non-toxic to human lymphocytic MT-2 cells, but only the aqueous extract of Baccharis trinervis exhibited potent anti-HIV activity in an in vitro MTT assay. To delineate the extract-sensitive phase, some studies of the antiviral properties of the active extract are described in this paper. Based on the results presented here, a separation scheme was devised, which permitted the preliminary fractionation of the extract, with the aim of finding an inhibitor of this virus.  (+info)

Sexual differences in reproductive phenology and their consequences for the demography of Baccharis dracunculifolia (Asteraceae), a dioecious tropical shrub. (3/30)

Patterns of phenological variation and reproductive investment were studied in the dioecious shrub Baccharis dracunculifolia DC (Asteraceae), and possible consequences on survivorship were evaluated. The sex ratio was determined in a natural field population (n = 921) of B. dracunculifolia in Belo Horizonte, Brazil. Fifty-two males and 56 females were sampled at random from this population. During the reproductive season of 1999, inflorescence production, shoot growth and mortality, and xylem water potential were recorded for each individual. The population sex ratio was male-biased (1.27 : 1, P < 0.05), and was associated with a higher mortality of female shoots (38.4 vs. 23.1 %, P < 0.05), and individuals (17.8 vs. 11.5 %, P < 0.1), despite lower water stress in female plants. Flowering phenology also differed between the sexes, with males producing more inflorescences, and earlier, than females. Owing to fruit maturation, the number of inflorescences supported by females was higher than that supported by males later in the reproductive season. This occurred during the dry season, and drought stress may have been responsible for the greater female mortality. Thus, the male-biased sex ratio in this population of B. dracunculifolia is probably due to different reproductive functions of males and females. Intersexual differences in reproductive phenology had consequences for plant demography.  (+info)

A new ent-clerodane diterpene from the aerial parts of Baccharis gaudichaudiana. (4/30)

A new ent-clerodane diterpene, named bacchariol (1) was isolated from the aerial parts of Baccharis gaudichaudiana DC. (Compositae), together with known ent-clerodane diterpenes (2, 3), eight known flavonoids (4-11) and 3, 5-dicaffeoylquinic acid (12). Their structures were determined by spectroscopic analyses. Flavonoids (7, 8, 11) and 12 showed moderate scavenging activities toward 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radicals.  (+info)

Direct evidence for the plant origin of Brazilian propolis by the observation of honeybee behavior and phytochemical analysis. (5/30)

To identify the plant origin of Brazilian propolis directly, we observed the behavior of honeybees in Minas Gerais State of Brazil. Honeybee workers bit and chewed leaves of the plant, Baccharis dracunculifolia, packed the material into their pollen basket, brought it back to their nest, and used it as propolis. We collected the leaves of B. dracunculifolia and propolis, and compared their constituents by liquid chromatography-mass spectrometry (LC/MS) analysis. There was no difference between the chemical constituents of the ethanol extracts of B. dracunculifolia and those of propolis. This indicates directly that the plant origin of Brazilian propolis is B. dracunculifolia.  (+info)

Differentiation of species of the Baccharis genus by HPLC and chemometric methods. (6/30)

Phytochemical investigation of the aerial parts of three Baccharis species (Asteraceae family) was performed using HPLC and chemometric methods, with the objective of distinguishing between three morphologically very similar species: Baccharis genistelloides Persoon var. trimera (Less.) DC, B. milleflora (Less.) DC and B. articulata (Lam.) Persoon. With the help of Principal Component Analysis (PCA) and variance weights, it was possible to characterize the chromatographic profiles of the alcoholic extracts of the three species. Application of Soft Independent Modeling of Class Analogy (SIMCA) and K-Nearest Neighbor (KNN) methods on a training set of 74 extracts resulted in models that correctly classified all eight samples in an independent test set.  (+info)

Comparative evaluation of in-vitro effects of Brazilian green propolis and Baccharis dracunculifolia extracts on cariogenic factors of Streptococcus mutans. (7/30)

Streptococcus mutans triggers dental caries establishment by two major factors: synthesis of organic acids, which demineralize dental enamel, and synthesis of glucans, which mediate the attachment of bacteria to the tooth surface. Propolis is a natural product that may prevent dental caries. Baccharis dracunculifolia DC (Asteraceae), a native plant from Brazil, is the most important botanical origin for the production of green propolis (Brazilian propolis) by honeybees. However, whether B. dracunculifolia (Bd) has an anticariogenic effect, like green propolis, remains unknown. Herein, we have made a comparative evaluation of the effects of extracts from green propolis and Bd on the glucan synthesis and acidogenic potential of S. mutans. The inhibitory effects of the extracts on bacterial acid production were evaluated through the potentiometric measurement of pH from bacterial suspensions treated with serial concentrations of both extracts. Besides presenting close inhibitory values at the same concentration range, Bd leaf rinse and green propolis extracts had similar IC(50) values (0.41 and 0.34 mg/ml, respectively). Both extracts produced a bacteriostatic effect on S. mutans cultures at a concentration of 0.40 mg/ml. Estimated inhibitory values of green propolis and Bd leaf rinse extracts on the synthesis of insoluble glucans (IC(50)=12.9 and 25.0 microg/ml, respectively) and soluble glucans (IC(50)=50.4 and 49.1 microg/ml, respectively) were not significantly different from each other at p<0.05. The results demonstrate that Bd leaf rinse and green propolis extracts have similar inhibitory effects on the S. mutans cariogenic factors evaluated herein, and allowed us to suggest that Bd leaves may be a potential source for pharmaceutical products employed for this purpose.  (+info)

Numerical taxonomy characterization of Baccharis genus species by ultraviolet-visible spectrophotometry. (8/30)

Numerical taxonomy characterization of Baccharis genus species was performed using ultraviolet-visible spectrophotometry. The aim was to present a more convenient, more practical, more economic and faster method based on chemometric methods and UV-vis absorbance to give the most information about species identity and discrimination, especially when their classification has been doubtful. Three Baccharis species: B. genistelloides Persoon var. trimera (Less.) DC, B. milleflora (Less.) DC, and B. articulata (Lam.) Persoon were included in the study. With the help of principal component analysis (PCA) and cluster analysis (CA), we could characterize the three species. Application of soft independent modeling of class analogy (SIMCA) and K-nearest neighbor (KNN) methods on a training set of 65 extracts resulted in models that correctly classified all samples of an independent validation set, eight samples of B. genistelloides Persoon var. trimera (Less.) DC and one sample donated by Prof. Alarich Schultz Herbarium, Porto Alegre-RS, Brazil.  (+info)

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