Juliana S. Coppede

An ent-kaurane-type diterpene in Croton antisyphiliticus mart.

Croton antisyphiliticus is a medicinal plant widely used in the treatment of microbial infections, especially those affecting the genital tract. Crude extract, fractions and pure compound isolated from roots of this species were investigated to validate their antimicrobial activity against Escherichia coli and Staphylococcus aureus. The compound ent-kaur-16-en-18-oic acid was isolated as a major component (0.7% of crude extract), and its MIC value determined against S. aureus (ATCC 6538) was 250 μg/mL. This is the first phytochemical work on the species monitored with antimicrobial assay.

Mevalonate-derived quinonemethide triterpenoid from in vitro roots of Peritassa laevigata and their localization in root tissue by MALDI imaging.

Biosynthetic investigation of quinonemethide triterpenoid 22β-hydroxy-maytenin (2) from in vitro root cultures of Peritassa laevigata (Celastraceae) was conducted using 13C-precursor. The mevalonate pathway in P. laevigata is responsible for the synthesis of the quinonemethide triterpenoid scaffold. Moreover, anatomical analysis of P. laevigata roots cultured in vitro and in situ showed the presence of 22β-hydroxy-maytenin (2) and maytenin (1) in the tissues from transverse or longitudinal sections with an intense orange color. MALDI-MS imaging confirmed the distribution of (2) and (1) in the more distal portions of the root cap, the outer cell layers, and near the vascular cylinder of P. laevigata in vitro roots suggesting a role in plant defense against infection by microorganisms as well as in the root exudation processes.

Genetic and chemical diversity of Uncaria tomentosa (Willd. ex. Schult.) DC. in the Brazilian Amazon

Uncaria tomentosa (Willd. ex Schult.) DC., a plant native to the Amazon region, is used widely in popular medicine and by the pharmaceutical industry because of its anti-inflammatory activity. However, the survival of this species is endangered by deforestation and indiscriminate collection, and a preservation plan is urgently required. The objectives of this study were to determine the genetic and chemical variability between and within eight populations of U. tomentosa from the Brazilian states of Acre, Pará and Amapá, and to investigate possible correlations between genetic and geographical distances, and between geographical distances or altitude and the accumulation of bioactive oxindole alkaloids. Three sequence-related amplified polymorphism (SRAP) markers were employed to fingerprint genomic DNA, and the amounts of mitraphylline and isomitraphylline in leaf samples were established by high-performance liquid chromatography. Although significant divergence existed between the tested populations (FST = 0.246), the largest genetic diversity and the highest percentage of polymorphism (95.68%) was found within the population from Mâncio Lima, Acre. Gene flow was considered rather limited (Nm = 1.57), and no correlations between genetic and geographical distances were detected, suggesting that population structure followed an island model. Accumulations of mitraphylline and isomitraphylline varied in the range 32.94 to 0.57 and 3.75 to 0.36 mg g-1 dry weight, respectively. The concentration of isomitraphylline was positively influenced by altitude, such that the population collected at the site with the highest elevation (Tarauacá, Acre) exhibited the greatest alkaloid content. SRAP markers were very efficient in fingerprinting genomic DNA from U. tomentosa populations and clearly showed that genetic variability within populations was greater than between populations. A conservation and management plan should prioritize the creation of germplasm banks to prevent the loss of existing genetic variability, particularly within alkaloid-rich populations such as those of Tarauacá.

Improved production of quinone-methide triterpenoids by Cheiloclinium cognatum root cultures: possibilities for a non-destructive biotechnological process

Quinone-methide triterpenoids (QMTs) derived from species of the family Celastraceae have long been used as anti-cancer, anti-inflammatory, anti-oxidant, anti-malarial and insecticidal agents. The main problem in producing QMTs on a large-scale from natural sources is the low amounts (<0.4% dry weight) produced by plants grown in vivo. The aim of this study was to compare the levels of QMTs accumulated by roots of Cheiloclinium cognatum cultured in vitro with those of in vivo plants aged 6 months to 10 years. The highest levels of QMTs produced by in vivo specimens were found in root bark of 10-year old plants, but in vitro cultured roots produced 3.52-times more 22β-hydroxy-maytenin and 11.46-times more maytenin. Most importantly, the cultured roots excreted QMTs into the growth medium, thereby facilitating the large-scale production, extraction and purification of these bioactive compounds by means of a continuous and non-destructive bioprocess that would preserve the root cultures.

Genetic structure and chemical diversity in natural populations of Uncaria guianensis (Aubl.) J.F.Gmel. (Rubiaceae)

Uncaria guianensis is native to the Amazon and is used traditionally as an anti-inflammatory. Natural populations of the species have declined markedly in recent times because of strong anthropic pressure brought about by deforestation and indiscriminate collection. The aim of the present study was to assess the genetic and chemical diversity among eight natural populations of U. guianensis located in the Brazilian states of Acre, Amapá and Amazonas. A set of four primer combinations was employed in sequence-related amplified polymorphism (SRAP) amplifications of leaf DNA, and the fragments were analyzed in an LI-COR model 4300 DNA Analyzer. Genetic variability within the populations (81%) was substantially greater than that detected between them (19%). The highest percentage of polymorphic loci (90.21%) and the largest genetic variability were observed in the population located in Mazagão, Amapá. Genetic differentiation between populations was high (Fst = 0.188) and the studied populations formed three distinct genetic groups (K = 3). The population located in Assis Brasil, Acre, presented the highest average content of the mitraphylline (0.60 mg/g dry weight,). However, mitraphylline and isomitraphylline not detected in most individuals in the studied populations, and it is questionable whether they should be considered as chemical markers of the species. The genetic data confirm the urgent need for conservation programs for U. guianensis, and for further studies aimed at ascertaining the genetic basis and heritability of alkaloid accumulation.

Costus spiralis (Jacq.) Roscoe: a novel source of flavones with α-glycosidase inhibitory activity

Costus spiralis, a plant used in traditional Brazilian medicine for the treatment of complications in diabetes, was investigated. Assay of hexane, ethyl acetate, methanol, and aqueous fractions obtained by partition of a crude methanol extract of dried leaves of C. spiralis revealed that AGI activity was confined to the ethyl acetate fraction. Purification of this fraction yielded schaftoside and isoschaftoside. The AGI activities of the two flavones were lower than, but comparable with, that of the anti‐diabetic drug acarbose. In contrast, the IC50 value of the ethyl acetate fraction was 1.95‐, 2.34‐, and 2.22‐fold higher than those of acarbose, schaftoside, and isoschaftoside, respectively. The results demonstrate for the first time that schaftoside and isoschaftoside are responsible, in part, for the AGI activity of C. spiralis. Our study suggests that further investigations into C. spiralis may lead to the discovery of additional compounds with antihyperglycemic activity.

BIO068 Inhibitory effect of extracts of Croton antisyphilticus in biofilm production of Staphylococcus aureus causing bovine mastitis.

The bovine mastitis is the main disease that affects dairy herds. Staphylococcus aureus as the etiologic agent is highly prevalent and difficult to control. Among the various virulence factors of the pathogen the ability to form biofilms, which are bacteria adhered to a surface surrounded by a matrix of organic polymers, gives great protection by preventing the action of phagocytic cells and the direct action of antibiotics on them. Because of the need to discover novel compounds that are effective for the control and treatment of disease, recent studies have demonstrated significant results in the inhibition of reduction of biomass or biofilm using vegetable extracts and isolated compounds.

PNS014 Cytotoxicity of natural chemicals against normal and tumor cell lines

More recently there has been observed an increased number of scientific studies with medicinal plants in search of bioactive molecules to be used in the development of new drugs. Plant species are sources of a great diversity of natural chemicals with various pharmacological activities. In this context the discovery of new antineoplastics, has been the aim of innumerable research groups using medicinal plants as source of drugs. The effective results obtained from studies using the species Catharanthus roseus and Podophyllum peltatum that produce the antineoplastic secondary metabolites vinblastine, vincristine and etoposide, respectively, motivated us to investigate the efficacy of the triterpenes betulinic acid, oleanolic acid and ursolic acid synthesized in Jacaranda decurrens, a species endemic to the Brazilian Cerrado region.