Copaifera spp. oleoresins and two isolated compounds (ent-kaurenoic and ent-polyalthic acid) inhibit Toxoplasma gondii growth in vitro.

Toxoplasmosis affects about one-third of the world's population. The disease treatment methods pose several side effects and do not efficiently eliminate the parasite, making the search for new therapeutic approaches necessary. We aimed to assess the anti-Toxoplasma gondii activity of four Copaifera oleoresins (ORs) and two isolated diterpene acids, named ent-kaurenoic and ent-polyalthic acid. We used HeLa cells as an experimental model of toxoplasmosis. Uninfected and infected HeLa cells were submitted to the treatments, and the parasite intracellular proliferation, cytokine levels and ROS production were measured. Also, tachyzoites were pre-treated and the parasite invasion was determined. Finally, an in silico analysis was performed to identify potential parasite targets. Our data show that the non-cytotoxic concentrations of ORs and diterpene acids controlled the invasion and proliferation of T. gondii in HeLa cells, thus highlighting the possible direct action on parasites. In addition, some compounds tested controlled parasite proliferation in an irreversible manner. An additional and non-exclusive mechanism of action involves the modulation of host cell components, by affecting the upregulation of the IL-6. Additionally, molecular docking suggested that ent-polyalthic acid has a high affinity for the active site of the TgCDPK1 protein. Copaifera ORs have great antiparasitic activity against T. gondii, and this effect can be partially explained by the presence of the isolated compounds ent-kaurenoic and ent-polyalthic acid.

Diterpenoids from Gutierrezia sarothrae and G. microcephala: Chemical diversity, chemophenetics and implications to toxicity in grazing livestock.

Broom snakeweed (Gutierrezia sarothrae) and threadleaf snakeweed (G. microcephala) are suffrutescent plants found in many parts of western US rangelands and are possibly toxic to grazing livestock. The toxic components are not known, but it has been suggested that the diterpene acids may be both toxic and abortifacient. One hundred sixty-two samples of snakeweed were collected from 55 locations in Colorado, Oklahoma, New Mexico, Texas, Wyoming and Utah and were taxonomically classified. Samples were analyzed by GC-MS in a chemophenetic analysis and grouped into individual chemotypes based on diterpene acid content. The GC-MS profiles were found to be diverse showing at least eight different chemotypes. From each of the chemotypes the major diterpene acids were isolated and characterized by IR, MS and NMR spectroscopy. Twenty-one diterpenoids were identified and found to be a mix of furano, lactone, di-acid and esters of labdane, ent-labdane and chlerodane acids and alcohols. Only four of the 21 compounds isolated had been previously reported as occurring in G. sarathorea or G. microcephala, while another eight compounds were previously reported from other Gutierrezia or related species. Nine of the isolated diterpenoids have not been previously reported and their structure elucidation is reported.

Population-wide shifts in herbivore resistance strategies over succession.

As a strategic cost-saving alternative to constitutive resistance, induction of resistance against herbivores in plants can be especially beneficial when enemies are scarce or variable in abundance. Although probably describing the two ends of a continuum, constitutive and induced resistance strategies have long been observed to trade off within species. Examining these traits among populations along a successional gradient can help explain how temporally variable environments can maintain genetic variation and how ecosystem processes are affected by shifting plant resistance trait expression over time. Here we leverage large experimental plots that represent a chronosequence of succession up to 15 yr in combination with common garden experiments to examine changes in the selective environment and genetic differences in tall goldenrod's (Solidago altissima) constitutive and induced resistance. We show that resistance against a specialist herbivore Trirhabda virgata was inducible in the plants originating from midsuccession, which coincides with the largest loads of herbivores. The flavonoid compound content of the leaves varied with successional stage of the population of origin, which is indicative of constitutive differences in secondary metabolite production. Finally, there was a clear trade-off between constitutive and induced resistance. Our study indicates that selection for resistance traits within a population can be highly variable over time and likely result in genetically determined shifts of resistance strategies over relatively short time periods via genotype sorting.

Antileishmanial activity of diterpene acids in copaiba oil

Leishmaniasis is a neglected tropical disease. According to the World Health Organization, there are approximately 1.5-two million new cases of cutaneous leishmaniasis each year worldwide. Chemotherapy against leishmaniasis is based on pentavalent antimonials, which were developed more than a century ago. The goals of this study were to investigate the antileishmanial activity of diterpene acids in copaiba oil, as well as some possible targets of their action against Leishmania amazonensis. Methyl copalate and agathic, hydroxycopalic, kaurenoic, pinifolic and polyaltic acids isolated from Copaifera officinales oleoresins were utilised. Ultrastructural changes and the specific organelle targets of diterpenes were investigated with electron microscopy and flow cytometry, respectively. All compounds had some level of activity against L. amazonensis. Hydroxycopalic acid and methyl copalate demonstrated the most activity against promastigotes and had 50% inhibitory concentration (IC50) values of 2.5 and 6.0 µg/mL, respectively. However, pinifolic and kaurenoic acid demonstrated the most activity against axenic amastigote and had IC50 values of 3.5 and 4.0 µg/mL, respectively. Agathic, kaurenoic and pinifolic acid caused significant increases in plasma membrane permeability and mitochondrial membrane depolarisation of the protozoan. In conclusion, copaiba oil and its diterpene acids should be explored for the development of new antileishmanial drugs.