| 1. |
- Arévalo-Lopéz, Diandra, et al.
(författare)
-
Leishmanicidal and cytotoxic activity from plants used in Tacana traditional medicine (Bolivia)
- 2018
-
Ingår i: Journal of Ethnopharmacology. - : Elsevier BV. - 0378-8741. ; 216, s. 120-133
-
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.
|
|
| 2. |
- Castañeta, Grover, et al.
(författare)
-
Microwave-Assisted Semisynthesis and Leishmanicidal Activity of Some Phenolic Constituents from Lichens
- 2023
-
Ingår i: separations. - 2297-8739. ; 10:10
-
Tidskriftsartikel (refereegranskat)abstract
- Leishmaniasis is considered one of the most untreated tropical diseases in the world. In this study, we investigated the in vitro leishmanicidal activity and cytotoxicity of various isolated lichen substances, including atranorin (1), usnic acid (2), gyrophoric acid (3), salazinic acid (4), galbinic acid (5), and parietin (6), and some semi-synthetic imine derivatives of usnic acid (7, 8, 9) and atranorin (10, 11, 12, 13). Imine condensation reactions with hydrazine and several amines were assisted by microwave heating, an efficient and eco-friendly energy source. The most interesting result was obtained for compound 2, which has high leishmanicidal activity but also high cytotoxicity. This cytotoxicity was mitigated in its derivative, 9, with better selectivity and high antileishmanic activity. This result may indicate that the usnic acid derivative (9) obtained using condensation with two cyclohexylamine groups is a promising lead compound for the discovery of new semisynthetic antiparasitic drugs.
|
|
| 3. |
- Erosa-Rejon, Gilda J., et al.
(författare)
-
Benzochromenes from the roots of Bourreria pulchra
- 2010
-
Ingår i: Phytochemistry Letters. - : Elsevier BV. - 1874-3900. ; 3:1, s. 9-12
-
Tidskriftsartikel (refereegranskat)abstract
- Two new benzochromenes, (6,6-dimethyl-2-methoxy-6H-benzo[c]chromen-9-yl)methanol (1), and 2-methoxy-6,6-dimethyl-6H-benzo[c]chromen-9-carbaldehyde (2), together with several already known metabolites, were isolated from the root extract of Bourreria pulchra (Boraginaceae). The structures of 1 and 2 were established on the basis of their spectroscopic data. Both were assayed for in vitro antiprotozoan activity, and especially 1 was found to possess significant activity against Leishmania mexicana and Trypanosoma cruzi parasites (IC50 4.6 mu g/mL and 7.5 mu g/mL, respectively). (C) 2009 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.
|
|
| 4. |
- Escobar, Zilma, et al.
(författare)
-
Synthesis of poinsettifolin A
- 2014
-
Ingår i: Tetrahedron. - : Elsevier BV. - 0040-4020. ; 70:47, s. 9052-9056
-
Tidskriftsartikel (refereegranskat)abstract
- A synthesis of poinsettifolin A (1), a prenylated flavonol isolated from Dorstenia poinsettifolia, is described. Two routes starting from quercetin were explored, and 1 could be prepared if a prenyl group first was incorporated at C-6 of the protected quercetin followed by a condensation with citral at C-8. The key synthetic steps are a Mitsunobu reaction, an europium (III)-catalysed Claisen rearrangement coupled with cross-metathesis, and a benzopyran-forming geranylation. The two geranylated 3,5,3',4'-tetrahydroxyflavonols prepared, 1 and 3, were assayed for antileishmanial activity against Leishmania amazonensis and Leishmania braziliensis, and found to be active. Compound 3 showed cytotoxic activity against leukaemia and lung cancer cells while 1 lacked cytotoxicity. (C) 2014 Elsevier Ltd. All rights reserved.
|
|
| 5. |
- Gonzales-Ramirez, Mariela, et al.
(författare)
-
Trichilones A–E: New Limonoids from Trichilia adolfi
- 2021
-
Ingår i: Molecules. - : MDPI AG. - 1420-3049. ; 26:11
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
|
|
| 6. |
- Limachi, Ivan, et al.
(författare)
-
Antiparasitic metabolites from hyptis brevipes, a tacana medicinal plant
- 2019
-
Ingår i: Natural Product Communications. - 1934-578X. ; 14:1, s. 55-58
-
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.
|
|
| 7. |
- Limachi, Ivan, et al.
(författare)
-
Trichilianones A-D, Novel Cyclopropane-Type Limonoids from Trichilia adolfi
- 2021
-
Ingår i: Molecules (Basel, Switzerland). - : MDPI AG. - 1420-3049. ; 26:4
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
|
|
| 8. |
- Maldonado, Eliana, et al.
(författare)
-
Antileishmanial metabolites from Trixis antimenorrhoea
- 2014
-
Ingår i: Phytochemistry Letters. - : Elsevier BV. - 1874-3900. ; 10, s. 281-286
-
Tidskriftsartikel (refereegranskat)abstract
- An ethanol extract of the aerial parts of Trixis antimenorrhoea was found to possess activity toward Leishmania brasiliensis. Two new metabolites, the nortrixane 1 and the trixanolide 2, and eleven known were isolated and characterized. The antileishmanial activity against the promastigote form of L. amazonensis and L. brasiliensis was assayed in vitro, and 2 exhibited potent activity with IC50 values below 1 mu g/mL toward both strains. The structures of the isolated compounds were elucidated by NMR spectroscopy and high-resolution mass spectrometry, and the absolute configuration of 2 was determined by using Mosher's ester protocol. (C) 2014 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.
|
|
| 9. |
- Maldonado, Eliana M., et al.
(författare)
-
Antileishmanial metabolites from Lantana balansae
- 2016
-
Ingår i: Brazilian Journal of Pharmacognosy. - : Springer Science and Business Media LLC. - 0102-695X. ; 26:2, s. 180-183
-
Tidskriftsartikel (refereegranskat)abstract
- Eleven compounds, 12-oxo-phytodienoic acid (1), persicogenin (2), eriodictyol 3ʹ4ʹ,7-trimethyl ether (3), phytol (4), spathulenol (5), 4-hydroxycinnamic acid (6), onopordin (7), 5,8,4ʹ-trihydroxy-7,3ʹ-dimethoxyflavone (8), quercetin (9), jaceosidin (10), and 8-hydroxyluteolin (11), were isolated from an ethanol extract of Lantana balansae Briq., Verbenaceae, that was found to possess antileishmanial activ-ity. The structures of the compounds were determined by NMR spectroscopy and HR mass spectrometry, and 1, 2, 3, 7, 8 and 9 were investigated for antiprotozoal activity toward promastigotes of Leishmania amazonensis and Leishmania braziliensis. Compound 1 was shown to be the most potent, with the IC50 values 2.0µM toward L. amazonensis and 0.68µM toward L. braziliensis, although less potent than the positive control Amphotericin B. All compounds have been reported previously, but this is the first report of the isolation of a cyclopentenone fatty acid (1) and flavanones (2 and 3) from a Lantana species.
|
|
| 10. |
- Terrazas, Paola, et al.
(författare)
-
SAR:s for the Antiparasitic Plant Metabolite Pulchrol. 1. The Benzyl Alcohol Functionality
- 2020
-
Ingår i: Molecules (Basel, Switzerland). - : MDPI AG. - 1420-3049. ; 25:13
-
Tidskriftsartikel (refereegranskat)abstract
- Pulchrol (1) is a natural benzochromene isolated from the roots of Bourreria pulchra, shown to possess potent antiparasitic activity towards both Leishmania and Trypanozoma species. As it is not understood which molecular features of 1 are important for the antiparasitic activity, several analogues were synthesized and assayed. The ultimate goal is to understand the structure-activity relationships (SAR:s) and create a QSAR model that can be used for the development of clinically useful antiparasitic agents. In this study, we have synthesized 25 2-methoxy-6,6-dimethyl-6H-benzo[c]chromen analogues of 1 and its co-metabolite pulchral (5a), by semi-synthetic procedures starting from the natural product pulchrol (1) itself. All 27 compounds, including the two natural products 1 and 5a, were subsequently assayed in vitro for antiparasitic activity against Trypanozoma cruzi, Leishmania brasiliensis and Leishmania amazoniensis. In addition, the cytotoxicity in RAW cells was assayed, and a selectivity index (SI) for each compound and each parasite was calculated. Several compounds are more potent or equi-potent compared with the positive controls Benznidazole (Trypanozoma) and Miltefosine (Leishmania). The compounds with the highest potencies as well as SI-values are esters of 1 with various carboxylic acids.
|
|
| 11. |
- Terrazas, Paola, et al.
(författare)
-
SARs for the antiparasitic plant metabolite pulchrol. : 3. Combinations of new substituents in A/B-rings and A/C-rings
- 2021
-
Ingår i: Molecules. - : MDPI AG. - 1420-3049. ; 26:13
-
Tidskriftsartikel (refereegranskat)abstract
- The natural products pulchrol and pulchral, isolated from the roots of the Mexican plant Bourreria pulchra, have previously been shown to possess an antiparasitic activity toward Trypanosoma cruzi, Leishmania braziliensis and L. amazonensis, protozoa responsible for the Chagas disease and leishmaniasis. These infections have been classified as neglected diseases, and still require the development of safer and more efficient alternatives to their current treatments. Recent SAR stud-ies, based on the pulchrol scaffold, showed which effect the exchanges of its substituents have on the antileishmanial and antitrypanosomal activity. Many of the analogues prepared were shown to be more potent in vitro than pulchrol and the current drugs used to treat Leishmaniasis and the Chagas disease (Miltefosine and Benznidazole respectively). Moreover, indications of some of the possible interactions that may take place in the binding sites were also identified. In this study, 12 analogues with modifications at two or three different positions in two of the three rings were prepared by synthetic and semi-synthetic procedures. The molecules were assayed in vitro to-ward T. cruzi epimastigotes, L. braziliensis promastigotes and L. amazonensis promastigotes. Some compounds had higher antiparasitic activity than the parent compound pulchrol, and in some cases even Benznidazole and Miltefosine. The best combinations in this subset are with carbonyl functionalities in the A-ring and isopropyl groups in the C-ring, as well as with alkyl substituents in both the A- and C-rings combined with a hydroxyl group in position 1 (C-ring). The latter corresponds to cannabinol, which was shown to be potent toward all parasites.
|
|
