Secochiliolide ester derivatives: Preparation and evaluation of their antitrypanosomal and antimalarial efficacy.

In the present study, a series of new esters of secochiliolide acid (SA), a diterpene isolated from Nardophyllum bryoides, were synthesized in good yield. All compounds were evaluated for their in vitro antiparasitic properties (on Plasmodium falciparum and Trypanosoma brucei brucei) and cytotoxicity (on WI38, normal mammalian cells). They displayed moderate antitrypanosomal activity with IC values between 2.

Preparation and antitrypanosomal activity of secochiliolide acid derivatives.

Secochiliolide acid (1) isolated from the Patagonian shrub Nardophyllum bryoides, was used as a scaffold for the preparation of a series of nine derivatives. Compound 1 and its derivatives were tested against Trypanosoma cruzi epimastigotes grown in liquid media. It was first observed that secochiliolide acid (1) inhibited the proliferation of the parasites, with an IC50 of 2 μg/mL.

Chromium induced stress conditions in heterotrophic and auxotrophic strains of Euglena gracilis.

Oxidative stress parameter and antioxidant defense compound as well as enzyme activity were studied in relation to different Cr(VI) concentrations (0, 10, 20, 40 μM) in two strains of Euglena gracilis, one isolated from a polluted river (MAT) and the other acquired from a culture collection (UTEX). Chromium toxicity was measured in the auxotrophic and obligated heterotrophic variants of the two strains. Chromium uptake was higher in auxotrophic cultures, reflected by their higher cell proliferation inhibition and lower IC50 levels compared to heterotrophic ones.

Cytotoxic terpenoids from Nardophyllum bryoides.

The investigation of the ethanol extract of fresh aerial parts of the Patagonian shrub Nardophyllum bryoides collected in the province of Chubut, Argentina, yielded eleven terpenoids. These include: three seco-ent-halimane diterpenoids (1-3), two ent-halimanes (4-5) and six pentacyclic oleanane and ursane triterpenoids (6-11). Four of these compounds (2, 6, 8 and 11) are hitherto unknown, while two others (1 and 4) have been previously reported but only as synthetic products.

Effect of chromium on the fatty acid composition of two strains of Euglena gracilis.

The effect of hexavalent chromium on fatty acid composition was studied in two strains of Euglena gracilis; UTEX 753 (from the Culture Collection of Algae of Texas University, USA) and MAT (isolated from a highly polluted River). Both were grown in photoauxotrophic and photoheterotrophic conditions and exposed to two metal concentrations, one below and one above IC50. The high malondialdehyde (MDA) levels (3 to 7-fold) obtained with chromium concentration above IC50, suggested the existence of metal-induced lipid peroxidation.