Rosendo Archbold

Passifloricins, polyketides α-pyrones from Passiflora foetida resin.

Abstract Three polyketides α-pyrones, named passifloricins, were isolated from Passiflora foetida resin; their structures and relative configurations were assigned through 2D NMR spectroscopic analyses. These types of compounds were not detected in other passion flowers.

Withajardins, withanolides with a new type of skeleton structure of withajardins A, B, C and D absolute configuration of withajardin C

Abstract Withajardins A, B, C and D are withanolides with a new skeleton isolated from the leaves of Deprea orinocensis . Their structure and the absolute configuration of withajardin C were established by spectral analysis, including 2D-NMR and X-ray diffraction. The 13 C NMR assignments of withajardins and acnistins were compared and biogenetic pathways to these compounds were formulated.

In vivo Antimalarial Activity of α-Mangostin and the New Xanthone δ-Mangostin

Based on the previously reported in vitro antiplasmodial activity of several xanthones from Garcinia mangostana, two xanthones, α‐mangostin and a new compound, δ‐mangostin, were isolated from mangosteen husk, and the in vitro antiplasmodial and cytotoxic effects were determined. α‐Mangostin was more active against the resistant Plasmodium falciparum chloroquine‐resistant (FCR3) strain (IC50 = 0.2 ± 0.01 μM) than δ‐mangostin (IC50 = 121.2 ± 1.0 μM). Furthermore, the therapeutic response according to the administration route was evaluated in a Plasmodium berghei malarial murine model. The greatest therapeutic response was obtained with intraperitoneal administration; these xanthones reduced parasitemia by approximately 80% with a daily dose of 100 mg/kg administered twice a day for 7 days of treatment. Neither compound was effective by oral administration. Noticeable toxicological effects were not observed. In addition to the antimalarial effect of these xanthones isolated from G. mangostana husk, the availability of larger amounts of husk raw material to purify the bioactive xanthones is advantageous, permitting additional preclinical assays or chemical transformations to enhance the biological activity of these substances. Copyright

Danilol, A New Drimane Sesquiterpene from Polygonum Punctatum Leaves

Abstract A new sesquiterpene related to the insecticide polygodial was obtained from P. punctatum leaves. Its structure was established as a tricyclic hemiacetal by means of 2D NMR spectroscopy. The compound was inactive against tick (Boophiilus microplus).

Phenylphenalenone phytoalexins, will they be a new type of fungicide?

Phenylphenalenones represent a kind of phytoalexins produced in leaves and rhyzomes of banana and plantains (Musaceae), as well as in species of other families. These compounds are synthesized in plants by induction with aminoglycosides, or in the first stages of attack by the pathogenic fungus Mycosphaerella fijensis, a causal agent of the disease known as Black Sigatoka, which reduces banana production. In this paper we report the biosynthesis, synthesis and antifungal activities of these kinds of compounds and discus the possibility to use phytoalexins inductors as plant protectants.

Actividad antimicobacteriana de algunas plantas de la flora colombiana.

The current incidence of tuberculosis worldwide and the presence of Mycobacterium tuberculosis multi-resistant strains to chemotherapy agents make it necessary the search for new compounds that can be used for the control of the illness. Myristicaceae, Magnoliaceae, Lauraceae and Piperaceae families present lignans, compounds that can be potential antimycobacterial agents. In this investigation extracts and fractions from Virola calophylla, V. flexuosa, Piper sp., P. hispidum and Dugandiodendron sp., present an in vitro antibacterial good activity against M. tuberculosis H37Rv. The isolation of lignans and one flavonoid is also reported.

Estructura y actividad de sapogeninas triterpenicas

La leishmaniasis es una enfermedad ampliamente difundida en America latina, desafortunadamente para su tratamiento hay muy pocas drogas, que tambien tienen una baja efectividad. Por esta razon el mundo urge de nuevas y mas efectivas moleculas. En la busqueda de sustancias antiparasitarias se detecto una alta actividad leishmanicida de Sapindus saponaria ricas en sapogeninas. El fraccionamiento y posterior purificacion se obtuvieron tres sapogeninas triterpenicas cuyas estructuras se describen ene este articulo.

Synthesis of α-hydroxyacetosyringone

A phytoalexin from papaya fruit has been synthesized in four steps; this procedure involved a Pummerer- type reaction.