Caryophyllene Oxide, the Active Compound Isolated from Leaves of Hymenaea courbaril L. (Fabaceae) with Antiproliferative and Apoptotic Effects on PC-3 Androgen-Independent Prostate Cancer Cell Line.

Cancer treatment frequently carries side effects, therefore, the search for new selective and effective molecules is indispensable. Hymenaea courbaril L. has been used in traditional medicine in South America to treat several diseases, including prostate cancer. Leaves' extracts from different polarities were evaluated using the 3-(4,5-methyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) cell viability assay to determine the cytotoxicity in prostate p53-null cells, followed by bio-guided fractionations to obtain the most cytotoxic fraction considering the selectivity index. The most cytotoxic fraction was analyzed by GC/MS to identify the active compounds. The majority compound, caryophyllene oxide, induced early and late apoptosis, depolarized the mitochondrial membrane, leading to several morphological changes and shifts in apoptotic proteins, and caspases were evidenced. Depolarization of the mitochondrial membrane releases the pro-apoptotic protein Bax from Bcl-xL. The apoptosis process is caspase-7 activation-dependent. Caryophyllene oxide is a safe anti-proliferative agent against PC-3 cells, inducing apoptosis with low toxicity towards normal cells.

Biochemical analysis of 'kerosene tree' Hymenaea courbaril L. under heat stress.

Hymenaea courbaril or jatoba is a tropical tree known for its medically important secondary metabolites production. Considering climate change, the goal of this study was to investigate differential expression of proteins and lipids produced by this tree under heat stress conditions. Total lipid was extracted from heat stressed plant leaves and various sesquiterpenes produced by the tree under heat stress were identified. Gas chromatographic and mass spectrometric analysis were used to study lipid and volatile compounds produced by the plant. Several volatiles, isoprene, 2-methyl butanenitrile, ß ocimene and a numbers of sesquiterpenes differentially produced by the plant under heat stress were identified. We propose these compounds were produced by the tree to cope up with heat stress. A protein gel electrophoresis (2-D DIGE) was performed to study differential expression of proteins in heat stressed plants. Several proteins were found to be expressed many folds different in heat stressed plants compared to the control. These proteins included heat shock proteins, histone proteins, oxygen evolving complex, and photosynthetic proteins, which, we believe, played key roles in imparting thermotolerance in Hymenaea tree. To the best of our knowledge, this is the first report of extensive molecular physiological study of Hymenaea trees under heat stress. This work will open avenues of further research on effects of heat stress in Hymenaea and the findings can be applied to understand how global warming can affect physiology of other plants.

Analysis of xyloglucans by ambient chloride attachment ionization tandem mass spectrometry.

Xyloglucan oligomers obtained upon enzyme digestion from Hymenaea courbaril, Arabidopsis Columbia-0 and mur3 were ionized and analyzed by using chloride anion attachment electrospray ionization (ESI) and tandem mass spectrometry. MW determination and structural elucidation of several xyloglucan oligomers was performed directly from the mixture solutions without sample pretreatment or derivatization. Sodium cation attachment was used to determine the number of xyloglucans present in the mixtures and their MWs. However, tandem mass spectrometry results showed that structure elucidation based on the sodium adducts is ambiguous. Chloride anion also forms stable adducts with these xyloglucans upon ESI. These adducts can be readily identified due to the chlorine isotope pattern. The mass spectral profile of xyloglucans obtained for the mixtures matches the HPAEC results, thus validating this methodology for the determination of the xyloglucan composition and the MW of each xyloglucan. Upon collisional activation in MS(2) experiments, the chloride anion adducts readily lose HCl, which helps verify the molecular weight of each xyloglucan. Isolating the resulting anion (deprotonated oligomer) and subjecting it to further collision-activated dissociation experiments (MS(n); n=3-4) yields useful structural information that allows the differentiation between isomeric anions and hence determination of the sequence of the xyloglucan oligomers. The deprotonated oligomers fragment by a stepwise loss of sugar units from the reducing end.

Do tropical wetland plants possess convective gas flow mechanisms?

• Internal pressurization and convective gas flow, which can aerate wetland plants more efficiently than diffusion, are common in temperate species. Here, we present the first survey of convective flow in a range of tropical plants. • The occurrence of pressurization and convective flow was determined in 20 common wetland plants from the Mekong Delta in Vietnam. The diel variation in pressurization in culms and the convective flow and gas composition from stubbles were examined for Eleocharis dulcis, Phragmites vallatoria and Hymenachne acutigluma, and related to light, humidity and air temperature. • Nine of the 20 species studied were able to build up a static pressure of > 50 Pa, and eight species had convective flow rates higher than 1 ml min(-1). There was a clear diel variation, with higher pressures and flows during the day than during the night, when pressures and flows were close to zero. • It is concluded that convective flow through shoots and rhizomes is a common mechanism for below-ground aeration of tropical wetland plants and that plants with convective flow might have a competitive advantage for growth in deep water.

Feeding selectivity by mantled howler monkeys (Alouatta palliata) in relation to leaf secondary chemistry in Hymenaea courbaril.

This study is a quantitative examination of primate feeding selectivity in relation to secondary chemistry within a single plant species, Hymenaea courbaril. It provides the first evidence that sesquiterpenes may act as feeding deterrents in mantled howler monkeys. A free-ranging group of mantled howler monkeys at the study site of Sector Santa Rosa, Area de Conservacion Guanacaste, Costa Rica were observed for the 2-month period of H. courbaril leaf flush in 1999. Tree characteristic data and leaf specimens were collected from 22 focal trees. Gas chromatography and mass spectrometry were used to estimate relative percentages of sesquiterpenes in leaf specimens. The monkeys fed only on the youngest leaves and only from particular trees. Whereas leaf stage selectivity was likely governed by tannin content and structural carbohydrates in younger and older leaf stages, respectively, differential tree use may be related to variability in sesquiterpene content. There is evidence that alpha-copaene may have played a role in interindividual tree use, and that cyperene may also be implicated. However, there is no reported evidence of antiherbivore activity for cyperene.