Browsing by Autor "Ivan Limachi"

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Antiparasitic Metabolites from Hyptis brevipes, a Tacana Medicinal Plant
(SAGE Publishing, 2019) Ivan Limachi; Claudia Condo; Camila Palma; Nélida Nina; Efraín Salamanca; Juan C. Ticona; Enrique Udaeta; Ninoska Flores; Alcides Serato; Natalio Marupa
A bioassay screening against protozoa parasites of several Tacana medicinal plants gave Hyptis brevipes (Id'ene eidhue), traditionally used as decoction for intestinal parasites, as the most active extract. In this work we did a bioguided isolation of active constituents found in leaves. Structure elucidation was carried out by NMR spectroscopy and MS spectrometry analyses. Active constituents showed differentiated activity towards Giardia lamblia, Trypanosoma cruzi, several Leishmania strains, Plasmodium falciparum and cytotoxicity against HeLa cells. Brevipolide H (1) was the less cytotoxic and best antiparasitic, while the catechol derivative (2) the most active and cytotoxic.
Leishmanicidal and cytotoxic activity from plants used in Tacana traditional medicine (Bolivia)
(Elsevier BV, 2018) Diandra Arévalo-Lopéz; Nélida Nina; Juan C. Ticona; Ivan Limachi; Efraín Salamanca; Enrique Udaeta; Crispín Paredes; Boris Espinoza; Alcides Serato; David Garnica
Trichilianones A-D, Novel Cyclopropane-Type Limonoids from Trichilia adolfi
(Multidisciplinary Digital Publishing Institute, 2021) Ivan Limachi; Mariela González-Ramírez; Sophie Manner; Juan C. Ticona; Efraín Salamanca; Alberto Giménez; Olov Sterner
The fractionation of an ethanol extract of the bark of Trichilia adolfi yielded four novel limonoids (trichilinones A-D, 1-4), with five fused rings and related to the hortiolide-type limonoids. Starting with an ε-lactone, which is α,β-unsaturated in trichilinones A and D (1 and 4), attached to a tetrahydrofuran ring that is connected to an unusual bicyclo [5.1.0] hexane system, joined with a cyclopentanone with a 3-furanyl substituent [(2-oxo)-furan-(5H)-3-yl in trichilinone D (4)], the four compounds isolated display a new 7/5/3/5/5 limonoid ring system. Their structures were established based on extensive analysis of NMR spectroscopic data. As the crude extract possessed anti-leishmanial properties, the compounds were assayed for cytotoxic and anti-parasitic activities in vitro in murine macrophages cells (Raw 264.7) and leishmania promastigotes (L. amazoniensis and L. braziliensis), respectively. The compounds showed moderate cytotoxicity (approximately 70 μg/mL), but are not responsible for the leishmanicidal effect of the extract.
Trichilones A–E: New Limonoids from Trichilia adolfi
(Multidisciplinary Digital Publishing Institute, 2021) Mariela González-Ramírez; Ivan Limachi; Sophie Manner; Juan C. Ticona; Efraín Salamanca; Alberto Giménez; Olov Sterner
In addition to the trichilianones A-D recently reported from Trichilia adolfi, a continuing investigation of the chemical constituents of the ethanol extract of the bark of this medicinal plant yielded the five new limonoids 1-5. They are characterized by having four fused rings and are new examples of prieurianin-type limonoids, having a ε-lactone which in 4 and 5 is α, β- unsaturated. The structures of the isolated metabolites were determined by high field NMR spectroscopy and HR mass spectrometry. The new metabolites were shown to have the ε-lactone fused with a tetrahydrofuran ring which is connected to an oxidized hexane ring joined with a cyclo-pentanone having a 3-furanyl substituent. As the crude extract possesses antileishmanial activity, the compounds were assayed for cytotoxic and antiparasitic activities in vitro in murine macrophage cells (raw 264.7 cells) and in Leishmania amazoniensis as well as L. braziliensis promastigotes. Metabolites 1-3 and 5 showed moderate cytotoxicity (between 30-94 µg/mL) but are not responsible for the antileishmanial effect of the extract.