Jorge Daniel Coussio

Argentine plant extracts active against polymerase and ribonuclease H activities of HIV-1 reverse transcriptase

Lipophilic and hydrophilic extracts of four Argentine plants (Gamochaeta simplicaulis Cabr. 1, Achyrocline flaccida Wein. D. C. 2, Eupatorium buniifolium H. et A. 3, and Phyllanthus sellowianus Muell. Arg. 4) were examined in vitro for their ability to inhibit the polymerase and ribonuclease H (RNase H) activities of human immunodeficiency virus type 1 (HIV‐1) reverse transcriptase (RT) (wild and Y181C mutant types). The active extracts were also examined as inhibitors of viral replication in HLT4LacZ‐1IIIB cell cultures, evaluating their cytotoxicity in parallel. Infusions 2I and 4I, among the crude extracts, showed the highest activity. These extracts were refractioned into four fractions; 2I4 and 4I4 were active as inhibitors of DNA‐polymerase (wild and Y181C types) and RNase H activities. These fractions were potent as inhibitors of viral replication and were not cytotoxic. Refractionation of 2I4 yielded five new fractions, two of which, 2I4‐4 and 2I4‐5, showed notable activity. Refractionation of 4I4 yielded four new fractions; of these, 4I4‐3 and 4I4‐4 were active. The marked biological activity found in the infusion of A. flaccida and P. sellowianus makes them sufficiently attractive to be considered in the combined chemotherapy of the disease. Copyright

Phenolic constituents of four Achyrocline species

Four species of Achyrocline were analysed for flavonoids and caffeic acid derivatives, each showing a typical pattern of distribution. Among the identified substances, only two groups characterize a given species: the epoxybutoxy derivatives and the calleryanins.

Inhibitory effects of various extracts of Argentine plant species on free-radical-mediated reactions and human neutrophil functions

Extracts of Argentine plant species used in folk medicine were evaluated for their antioxidant properties and ability to influence human neutrophil functions, including superoxide anion release and degranulation. The infusion and methanol extract of Achyrocline flaccida, and the infusion of Pterocaulon polystachium exhibited chain‐breaking antioxidant activity in Fe2+/ascorbate‐induced lipid peroxidation of rat liver microsomal fractions and scavenged peroxyl radicals in an aqueous assay system. Nevertheless their superoxide scavenging ability was lower. The dichloromethane extracts of Phyllanthus sellowianus, Achyrocline flaccida, Gamochaeta simplicicaulis, Pterocaulon polystachium and Eupatorium buniifolium, besides the infusion of Eupatorium buniifolium and the methanol extract of Pterocaulon polystachium, inhibited neutrophil functions.

5,7,3′,4′-Tetrahydroxy-6-methoxyflavanone from Eupatorium subhastatum

Abstract 5,7,3′,4′-Tetrahydroxy-6-methoxyflavanone has been isolated for the first time from Eupatorium subhastatum besides acacetin, hispidulin, eupato

Composition of the Essential Oil from Flowers and Leaves of Heterotheca latifolia Buckley (Compositae)

Abstract Oils obtained by hydrodistillation, separately from flowers and leaves of Heterotheca latifolia Buck. (Compositae), which is a weed in west central Argentina, were analyzed by GC and GC/MS. Twenty-eight compounds were identified in the flower oil representing 88.9%; and 90.7% of the leaf oil was represented by 15 compounds. Although the composition of both oils was similar, the quantity of individual components differed between them. The major components of both oils were borneol (19.0-39.9%) and camphor (12.0–24.3%). The monoterpene hydrocarbon content of the flower oil (47–3%) was much higher than in leaf oil (7.4%), while the oxygenated compounds were much higher in leaf oil (71.5%)