| 1. |
- Beniddir, Mehdi A., et al.
(författare)
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On the structures of the penduflorines from Tabernaemontana penduliflora
- 2023
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Ingår i: Fitoterapia. - : Elsevier. - 0367-326X .- 1873-6971. ; 167
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Tidskriftsartikel (refereegranskat)abstract
- The structures of the recently published monoterpene indole alkaloids penduflorines A and B (1a and 1b), isolated from Tabernaemontana penduliflora (Apocynaceae), have been revised. Rather than an inseparable mixture of two compounds, they appear to be the known alkaloid vobasine (2). Although we could not comprehensively revise the structures of penduflorines C-E due to lacking spectral data, since their structural elucidations were based on that of 1a and 1b, their structures should also be treated with caution.
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| 2. |
- Chepkirui, Carolyne, et al.
(författare)
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A new β-hydroxydihydrochalcone from Tephrosia uniflora, and the revision of three β-hydroxydihydrochalcones to flavanones.
- 2022
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Ingår i: Fitoterapia. - : Elsevier BV. - 1873-6971 .- 0367-326X. ; 158
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Tidskriftsartikel (refereegranskat)abstract
- The CH2Cl2/MeOH (1:1) extract of the stems of Tephrosia uniflora yielded the new β-hydroxydihydrochalcone (S)-elatadihydrochalcone-2'-methyl ether (1) along with the three known compounds elongatin (2), (S)-elatadihydrochalcone (3), and tephrosin (4). The structures were elucidated by NMR spectroscopic and mass spectrometric data analyses. Elongatin (2) showed moderate antibacterial activity (EC50 of 25.3μM and EC90 of 32.8μM) against the Gram-positive bacterium Bacilus subtilis, and comparable toxicity against the MCF-7 human breast cancer cell line (EC50 of 41.3μM). Based on the comparison of literature and predicted data with that obtained experimentally, we propose the revision of the structure of three β-hydroxydihydrochalcones to flavanones.
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| 3. |
- Chepkirui, Carolyne, et al.
(författare)
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Antiplasmodial and antileishmanial flavonoids from Mundulea sericea
- 2021
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Ingår i: Fitoterapia (Milano). - : Elsevier BV. - 0367-326X .- 1873-6971. ; 149
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Tidskriftsartikel (refereegranskat)abstract
- Five known compounds (1–5) were isolated from the extract of Mundulea sericea leaves. Similar investigation of the roots of this plant afforded an additional three known compounds (6–8). The structures were elucidated using NMR spectroscopic and mass spectrometric analyses. The absolute configuration of 1 was established using ECD spectroscopy. In an antiplasmodial activity assay, compound 1 showed good activity with an IC50 of 2.0 μM against chloroquine-resistant W2, and 6.6 μM against the chloroquine-sensitive 3D7 strains of Plasmodium falciparum. Some of the compounds were also tested for antileishmanial activity. Dehydrolupinifolinol (2) and sericetin (5) were active against drug-sensitive Leishmania donovani (MHOM/IN/83/AG83) with IC50 values of 9.0 and 5.0 μM, respectively. In a cytotoxicity assay, lupinifolin (3) showed significant activity on BEAS-2B (IC50 4.9 μM) and HePG2 (IC50 10.8 μM) human cell lines. All the other compounds showed low cytotoxicity (IC50 > 30 μM) against human lung adenocarcinoma cells (A549), human liver cancer cells (HepG2), lung/bronchus cells (epithelial virus transformed) (BEAS-2B) and immortal human hepatocytes (LO2)
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| 4. |
- Fossen, Torgils, et al.
(författare)
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A new protolimonoid from Capuronianthus mahafalensis
- 2012
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Ingår i: Fitoterapia (Milano). - : Elsevier BV. - 0367-326X .- 1873-6971. ; 83:5, s. 901-906
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Tidskriftsartikel (refereegranskat)abstract
- From stem barks of Capuronianthus mahafalensis (Meliaceae) endemic to Madagascar, a new protolimonoid named capulin containing a four membered ring in its side chain was isolated by repeated silica gel column chromatography. Its structure was determined by 1D and 2D NMR spectroscopy and high-resolution MS. To the best of our knowledge, this is the first time that a four-membered ring occurs in the side chain of protolimonoids.
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| 5. |
- Kalenga, Thobias M, et al.
(författare)
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Antibacterial and cytotoxic biflavonoids from the root bark of Ochna kirkii
- 2021
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Ingår i: Fitoterapia. - : Elsevier BV. - 1873-6971 .- 0367-326X. ; 151
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Tidskriftsartikel (refereegranskat)abstract
- The new isoflavonoid kirkinone A (1) and biflavonoid kirkinone B (2) along with six known compounds (3-8) were isolated from the methanolic extract of the root bark of Ochna kirkii. The compounds were identified by NMR spectroscopic and mass spectrometric analyses. Out of the eight isolated natural products, calodenin B (4) and lophirone A (6) showed significant antibacterial activity against the Gram-positive bacterium Bacillus subtilis with MIC values of 2.2 and 28μM, and cytotoxicity against the MCF-7 human breast cancer cell line with EC50 values of 219.3 and 19.2μM, respectively. The methanolic crude extract of the root bark exhibited cytotoxicity at EC50 8.4μg/mL. The isolated secondary metabolites and the crude extract were generally inactive against the Gram-negative Escherichia coli (MIC ≥400μg/mL). Isolation of biflavonoids and related secondary metabolites from O. kirkii demonstrates their chemotaxonomic significance to the genus Ochna and to other members of the family Ochnaceae.
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| 6. |
- Maeda, Gasper, et al.
(författare)
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Polyoxygenated cyclohexene derivatives and flavonoids from the leaves of Uvaria pandensis.
- 2022
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Ingår i: Fitoterapia. - : Elsevier BV. - 1873-6971 .- 0367-326X. ; 158
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Tidskriftsartikel (refereegranskat)abstract
- Three new oxygenated cyclohexene derivatives, pandensenol D - F (1-3), two new flavanoids, pandensone A and B (4-5), and seven known compounds (6-12) were isolated from the methanol extract of the leaves of Uvaria pandensis Verdc. (Annonaceae). The structures were characterized by NMR spectroscopic and mass spectrometric analyses. The isolated metabolites were evaluated for their antibacterial activity against the Gram-positive bacteria Bacillus subtilis and Staphylococcus epidermidis and the Gram-negative bacteria Enterococcus raffinosus, Escherichia coli, Paraburkholderia caledonica, Pectobacterium carotovorum and Pseudomonas putida, and for cytotoxicity against the MCF-7 human breast cancer cell line. Out of the tested compounds, pandensenol D (1) and (6',7'-dihydro-8'α,9'β-dihydroxy)-3-farnesylindole (12) showed weak whereas (8'α,9'β-dihydroxy)-3-farnesylindole (11) strong activity against B. subtilis. Four of the isolated compounds (1, 4, 11 and 12) showed moderate cytotoxicity against MCF-7 breast cancer cells (EC50>100μM).
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| 7. |
- Rajendran, Sanjeevan, et al.
(författare)
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Antibacterial eremophilane sesquiterpenoids from Xylaria feejeensis, an endophytic fungi of the medicinal plant Geophila repens
- 2023
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Ingår i: Fitoterapia. - : Elsevier. - 0367-326X .- 1873-6971. ; 167
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Tidskriftsartikel (refereegranskat)abstract
- Geophila repens (L.) I.M. Johnst (Rubiaceae) is a traditional medicinal plant used in Sri Lanka for the treatment of bacterial infections. Due to its rich endophytic fungi content, it was postulated that endophytically-produced specialized metabolites may be responsible for its purported antibacterial effects. To test this hypothesis, eight pure endophytic fungal cultures were isolated from G. repens then extracted and screened for antibacterial activity in a disc diffusion assay against Staphylococcus aureus, Bacillus cereus, Escherichia coli and Pseudomonas aeruginosa. Large scale culturing, extraction, and purification of the most active fungal extract, obtained from Xylaria feejeensis, led to the isolation of 6′,7′-didehydrointegric acid (1), 13-carboxyintegric acid (2), and four known compounds including integric acid (3). Compound 3 was isolated as the key antibacterial component (MIC = 16 μg/mL against Bacillus subtilis, 64 μg/mL against Methicillin-Resistant S. aureus). Compound 3 and its analogues were devoid of hemolytic activity up to the highest tested concentration of 45 μg/mL. This study demonstrates that specialized metabolites produced by endophytic fungi may contribute to the biological activity of some medicinal plants. Endophytic fungi should be evaluated as a potential source of antibiotics, especially from unexplored medicinal plants traditionally used for the treatment of bacterial infections.
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| 8. |
- Rodrigo, Gloria, et al.
(författare)
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Antiproliferative effects of curcuphenol, a sesquiterpene phenol.
- 2010
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Ingår i: Fitoterapia. - : Elsevier BV. - 1873-6971 .- 0367-326X. ; 81:7, s. 762-766
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Tidskriftsartikel (refereegranskat)abstract
- Curcuphenol is a sesquiterpene isolated from sponges and plants having several significant biological activities. The present study explored its effect on cell proliferation and apoptosis in Caco-2 human colon cancer cells. It was demonstrated that curcuphenol in concentrations in the range of 29-116microg/ml inhibited cell proliferation and DNA replication and induced cell death in a dose-dependent manner. The induction of apoptosis was associated with a stimulation of the activity of caspase-3. The findings presented here suggest that curcuphenol has antiproliferative and pro-apoptotic properties.
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| 9. |
- Sut, Stefania, et al.
(författare)
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Identification of tagitinin C from Tithonia diversifolia as antitrypanosomal compound using bioactivity-guided fractionation
- 2018
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Ingår i: Fitoterapia (Milano). - : Elsevier. - 0367-326X .- 1873-6971. ; 124, s. 145-151
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Tidskriftsartikel (refereegranskat)abstract
- Tithonia diversifolia (Asteraceae), is used as traditional medicine in tropical countries for the treatment of various diseases, including malaria. Although numerous studies have assessed the antimalarial properties, nothing is known about the effect of T. diversifolia extracts on trypanosomiasis. In this study extracts of T. diversifolia aerial parts were evaluated for their bioactivity against Trypanosoma brucei. The activity was studied against bloodstream forms of T. brucei (TC221), as well as against mammalian cells (BALB/3T3 mouse fibroblasts), as a counter-screen for toxicity. Both methanolic and aqueous extracts showed significant effects with IC50 values of 1.1 and 2.2 mu g/mL against T. brucei (TC221) and 5.2 and 3.7 mu g/mL against BALB/3T3 cells, respectively. A bioassay-guided fractionation on the methanolic extract yielded in identification of active fractions (F8 and F9) with IC50 values of 0.41 and 0.43 mu g/mL, respectively, against T. brucei (TC221) and 1.4 and 1.5 mu g/mL, respectively, against BALB/3T3 cells,. The phytochemical composition of the extracts and the purified fractions were investigated using HPLC-ESI-MS/MS and 1D and 2D NMR spectra showing the presence of sesquiterpene lactones that in turn were subjected to the isolation procedure. Tagitinin A and C were rather active but the latter presented a very strong inhibition on T. brucei (TC221) with an IC50 value of 0.0042 mu g/mL. This activity was 4.5 times better than that of the reference drug suramin. The results of this study shed light on the antitrypanosomal effects of T. diversifolia extracts and highlighted tagitinin C as one of the possible responsible for this effect. Further structure activity relationships studies on tagitinins are needed to consider this sesquiterpenes as lead compounds for the development of new antitrypanosomal drugs.
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| 10. |
- Umereweneza, Daniel, et al.
(författare)
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Antibacterial and cytotoxic prenylated dihydrochalcones from Eriosema montanum
- 2021
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Ingår i: Fitoterapia (Milano). - : Elsevier BV. - 0367-326X .- 1873-6971. ; 149
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Tidskriftsartikel (refereegranskat)abstract
- Two new prenylated dihydrochalcones (1,2) and eighteen known secondary metabolites (3−20) were isolated from the CH2Cl2-MeOH (1:1) extracts of the roots, the stem bark and the leaves of Eriosema montanum Baker f. (Leguminosae). The structures of the isolated compounds were characterized by NMR, IR, and UV spectroscopic and mass spectrometric analyses. The structures of compounds 5, 10, 11 and 13 were confirmed by single crystal X-ray diffraction. The antibacterial activity of the crude extracts and the isolated constituents were established against Gram-positive and Gram-negative bacteria. Among the tested compounds, 1–4 and 10 showed strong activity against the Gram-positive bacterium Bacillus subtilis with minimum inhibitory concentration (MIC) ranging from 3.1 to 8.9 μM, as did the leaf crude extract with an MIC of 3.0 μg/mL. None of the crude extracts nor the isolated compounds were active against Escherichia coli. Compounds 1, 3 and 4 showed higher cytotoxicity, evaluated against the human breast cancer cell line MCF-7, with EC50 of 7.0, 18.0 and 18.0 μM, respectively. These findings contribute to the phytochemical understanding of the genus Eriosema, and highlight the pharmaceutical potential of prenylated dihydrochalcones.
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