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- Arévalo-Lopéz, Diandra, et al.
(författare)
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Leishmanicidal and cytotoxic activity from plants used in Tacana traditional medicine (Bolivia)
- 2018
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Ingår i: Journal of Ethnopharmacology. - : Elsevier BV. - 0378-8741. ; 216, s. 120-133
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Tidskriftsartikel (refereegranskat)abstract
- Etnopharmacological relevance: Thirty-eight Tacana medicinal plant species used to treat skin problems, including leishmania ulcers, skin infections, inflammation and wound healing, were collected in the community of Buena Vista, Bolivia, with the Tacana people. Twenty two species are documented for the first time as medicinal plants for this ethnic group living in the northern area of the Department of La Paz. Aim of the study: To evaluate the leishmanicidal effect (IC50) and cytotoxicity (LD50) of the selected plants. To carry out bioguided studies on the active extracts. To assess the potential of Bolivian plant biodiversity associated with traditional knowledge in the discovery of alternative sources to fight leishmaniasis. Materials and methods: Seventy three ethanol extracts were prepared from 38 species by maceration and were evaluated in vitro against promastigotes of Leishmania amazonensis and L. braziliensis. Active extracts (IC50 ≤ 50 μg/mL) were fractionated by chromatography on Silica gel column and the fractions were assessed against the two Leishmania strains. The most active fractions and the crude extracts were evaluated against reference strains of L. amazonensis, L. braziliensis, L. aethiopica, two native strains (L. Lainsoni and L. braziliensis) and for cytotoxicity against HeLa cells. The chromatographic profile of the active fractions was obtained by reverse phase chromatography using HPLC. Results: From the 73 extracts, 39 extracts (53.4%) were inactive and 34 showed activity. Thirteen species were sselected for bioguided studies. The crude extracts and their 36 fractions were evaluated against two Leishmania strains. The most active fraction were tested in a panel of five leishmania strains and for cytotoxicity. The Selective Index (SI = LD50/IC50) was calculated, and were generally low. Retention time and UV spectra were recorded for the active fractions by HPLC-DAD using a reverse phase column. Profiles were very different from each other, showing the presence of different compounds. Conclusion: Bolivian traditional knowledge from the Tacanba was useful to identify plants with effect on Leishmania promastigotes. Chromatographic bioguided studies showed stronger leishmanicidal and cytotoxic activity for the medium polar fraction. HPLC analysis showed different chromatographic profiles of the active fractions.
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| 2. |
- Curi-Borda, Cecilia K, et al.
(författare)
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Multilayer Bixin Microcapsules: The Impact of Native Carbohydrates on the Microencapsulation Efficiency and Dispersion Stability
- 2019
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Ingår i: Foods. - : MDPI AG. - 2304-8158. ; 8:3
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Tidskriftsartikel (refereegranskat)abstract
- Bixin is a hydrophobic carotenoid present in the integument of the seeds of Bixa orellana. Microencapsulation was applied to obtain water dispersible formulations and protect the colorant against degradation. Microencapsulated systems were obtained by spray-drying a mild alkaline bixin dispersion with different encapsulating materials. The encapsulation trials were performed with and without native carbohydrates of the integument in addition to the main encapsulant. It was possible to dry dispersions with up to 10% bixin counted on total solids. All the studied systems were characterized by colorimetry, UV-vis spectroscopy, Scanning Electron Microscopy, light microscopy, turbidometric sedimentation analyses and laser light diffraction analyses. All the systems showed aqueous dispersibility but displayed differences in their transparency, UV-vis spectra and physical stability at pH 3. The results show that the native carbohydrates enhance the encapsulation efficiency of other encapsulating materials. The chemical composition of this native carbohydrate fraction shows the presence of polysaccharides containing arabinose, galactose and glucose as monomers. Starch was identified enzymatically. The native carbohydrates allowed the encapsulation of bixin in its native microcrystalline form, resulting in a multilayer structure after spray-drying. In addition, the colorant particles displayed dispersibility under acidic aqueous conditions suggesting that they are stabilized by the native carbohydrates after the microcapsules are dissolved.
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| 3. |
- Limachi, Ivan, et al.
(författare)
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Antiparasitic metabolites from hyptis brevipes, a tacana medicinal plant
- 2019
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Ingår i: Natural Product Communications. - 1934-578X. ; 14:1, s. 55-58
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 4. |
- Mendoza, Laura, et al.
(författare)
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Laccase mediator system for activation of agarose gel: Application for immobilization of proteins
- 2011
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Ingår i: Journal of Molecular Catalysis B: Enzymatic. - : Elsevier BV. - 1873-3158 .- 1381-1177. ; 68:3-4, s. 270-274
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Tidskriftsartikel (refereegranskat)abstract
- Cross-linked Sepharose beads were treated with laccase-TEMPO system for oxidation of the primary alcohol groups on the sugar moieties. Optimal activation conditions using Trametes versicolor laccase were at pH 5 and 22 degrees C, giving an aldehyde content of 55 mu mol g(-1) Sepharose with 28 units g(-1) of laccase and 12.5 mM TEMPO. The activated Sepharose was used for immobilization of trypsin as model protein. Highest degree of immobilization was obtained at pH 10.5 but the activity yield was only 31% of that loaded on the gel. The yield of gel bound trypsin activity was increased to 76% (corresponding to about 43 U g(-1) Sepharose) when the immobilization was performed in the presence of trypsin inhibitor, benzamidine. The immobilization yields were comparable to that obtained on the matrix activated using sodium periodate (containing 72 mu mol aldehyde per g Sepharose). Recycling and storage of the immobilized trypsin preparations showed high stability of the enzyme bound to laccase-TEMPO activated gel. (C) 2010 Elsevier B.V. All rights reserved.
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