| 1. |
- Deyou, Tsegaye, et al.
(författare)
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Rotenoids, Flavonoids, and Chalcones from the Root Bark of Millettia usaramensis
- 2015
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Ingår i: Journal of Natural Products. - : American Chemical Society (ACS). - 0163-3864 .- 1520-6025 .- 0974-5211. ; 78:12, s. 2932-2939
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Tidskriftsartikel (refereegranskat)abstract
- Five new compounds, 4-O-geranylisoliquiritigenin (1), 12-dihydrousararotenoid B (2), 12-dihydrousararotenoid C (3), 4'-O-geranyl-7-hydroxyflavanone (4), and 4'O-geranyl-7-hydroxydihydroflavanol (5), along with 12 known natural products (6-17) were isolated from the CH2Cl2/MeOH (1:1) extract of the root bark of Millettia usaramensis ssp. usaramensis by chromatographic separation. The purified metabolites were identified by NMR spectroscopic and mass spectrometric analyses, whereas their absolute configurations were established on the basis of chiroptical data and in some cases also by X-ray crystallography. The crude extract was moderately active (IC50 = 11.63 mu g/mL) against the ER-negative MDB-MB-231 human breast cancer cell line, and accordingly compounds 6, 8, 9, 10, 12, and 16 also showed moderate to low cytotoxic activities (IC50 25.7-207.2 mu M). The new natural product 1 exhibited antiplasmodial activity with IC50 values of 3.7 and 5.3 mu M against the chloroquine-sensitive 3D7 and the chloroquine-resistant Dd2 Plasmodium falciparum strains, respectively, and was also cytotoxic to the HEK293 cell line.
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| 2. |
- Muhammad, Taj, et al.
(författare)
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Exploring the limits of cyanobactin macrocyclase PatGmac : Cyclization of PawS-derived peptide sunflower trypsin inhibitor-1 and cyclotide kalata B1
- 2023
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Ingår i: Journal of Natural Products. - : American Chemical Society (ACS). - 0974-5211 .- 0163-3864 .- 1520-6025. ; 86:3, s. 566-573
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Tidskriftsartikel (refereegranskat)abstract
- The subtilisin-like macrocyclase PatGmac is produced by the marine cyanobacterium Prochloron didemni. This enzyme is involved in the last step of the biosynthesis of patellamides, a cyanobactin type of ribosomally expressed and post-translationally modified cyclic peptides. PatGmac recognizes, cleaves, and cyclizes precursor peptides after a specific recognition motif comprised of a C-terminal tail with the sequence motif -AYDG. The result is the native macrocyclic patellamide, which has eight amino acid residues. Macrocyclase activity can be exploited by incorporating that motif in other short linear peptide precursors, which then are formed into head-to-tail cyclized peptides. Here, we explore the possibility of using PatGmac in the cyclization of peptides larger than the patellamides, namely, the PawS-derived peptide sunflower trypsin inhibitor-1 (SFTI-1) and the cyclotide kalata B1. These peptides fall under two distinct families of disulfide constrained macrocyclic plant peptides. They are both implicated as scaffolds for drug design due to their structures and unusual stability. We show that PatGmac can be used to efficiently cyclize the 14 amino acid residue long SFTI-1, but less so the 29 amino acid residue long kalata B1.
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| 3. |
- Abdissa, Negera, et al.
(författare)
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Naphthalene Derivatives from the Roots of Pentas parvifolia and Pentas bussei
- 2016
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Ingår i: Journal of natural products. - : American Chemical Society (ACS). - 0163-3864 .- 1520-6025. ; 79:9, s. 2181-2187
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Tidskriftsartikel (refereegranskat)abstract
- The phytochemical investigation of the CH2Cl2/MeOH (1:1) extract of the roots of Pentas parvifolia led to the isolation of three new naphthalenes, parvinaphthols A (1), B (2), and C (3), two known anthraquinones, and five known naphthalene derivatives. Similar investigation of the roots of Pentas bussei afforded a new polycyclic naphthalene, busseihydroquinone E (4), a new 2,2′-binaphthralenyl-1,1′-dione, busseihydroquinone F (5), and five known naphthalenes. All purified metabolites were characterized by NMR and MS data analyses, whereas the absolute configurations of 3 and 4 were determined by single-crystal X-ray diffraction studies. The E-geometry of compound 5 was supported by DFT-based chemical shift calculations. Compounds 2-4 showed marginal cytotoxicity against the MDA-MB-231 human triple-negative breast cancer cell line with IC50 values ranging from 62.3 to 129.6 μM. © 2016 The American Chemical Society and American Society of Pharmacognosy.
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| 4. |
- Appendino, Giovanni, et al.
(författare)
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A meroterpenoid NF-kappa B inhibitor and drimane sesquiterpenoids from asafetida
- 2006
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Ingår i: Journal of Natural Products. - : American Chemical Society (ACS). - 0163-3864 .- 1520-6025. ; 69:7, s. 1101-1104
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Tidskriftsartikel (refereegranskat)abstract
- Investigation of an acetone extract from asafetida afforded two drimane sesquiterpene dienones (fetidones A and B, 1a,b) and several known sesquiterpene coumarin ethers, one of which (8-acetoxy-5-hydroxyumbelliprenin, 2a) showed potent and specific NF-kappa B-inhibiting properties. This, coupled to a negligible cytotoxicity, qualifies 2a as a new anti-inflammatory chemotype, and its occurrence in asafetida might rationalize the use of this gum resin to alleviate and prevent colon inflammatory disturbances.
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| 5. |
- Appendino, G, et al.
(författare)
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A new P-glycoprotein inhibitor from the caper spurge (Euphorbia lathyris).
- 2003
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Ingår i: Journal of Natural Products. - : American Chemical Society (ACS). - 0163-3864 .- 1520-6025. ; 66:1, s. 140-142
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Tidskriftsartikel (refereegranskat)abstract
- The macrocyclic lathyrane polyester Euphorbia factor L10 (1a) has been obtained from the seeds of the caper spurge (E. lathyris). The interaction of L10 (1a) and its acetyl derivative (1b) with P-glycoprotein, a multidrug transporter overexpressed in cancer cells and responsible for resistance to chemotherapy, was investigated. The results established lathyrane diterpenoids as a novel chemotype for P-glycoprotein inhibitors.
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| 6. |
- Appendino, G, et al.
(författare)
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Antibacterial galloylated alkylphloroglucinol glucosides from myrtle (Myrtus communis)
- 2006
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Ingår i: Journal of Natural Products. - : American Chemical Society (ACS). - 0163-3864 .- 1520-6025. ; 69:2, s. 251-254
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Tidskriftsartikel (refereegranskat)abstract
- An investigation of the polar glycosidic fraction from the leaves of myrtle afforded four galloylated nonprenylated phloroglucinol glucosides (3a-d) related to the endoperoxide hormone G3 (4) in terms of structure and biogenesis. Despite their close similarity, significant antibacterial activity was shown only by one of these compounds (3b, gallomyrtucommulone B), while the G3 hormone (4) was inactive.
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| 7. |
- Appendino, Giovanni, et al.
(författare)
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Arzanol, an anti-inflammatory and anti-HIV-1 phloroglucinol alpha-pyrone from Helichrysum italicum ssp microphyllum
- 2007
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Ingår i: Journal of Natural Products. - : American Chemical Society (ACS). - 0163-3864 .- 1520-6025. ; 70:4, s. 608-612
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Tidskriftsartikel (refereegranskat)abstract
- An acetone extract of Helichrysum italicum ssp. microphyllum afforded the phloroglucinol alpha-pyrone arzanol (1a) as a potent NF-kappa B inhibitor. Arzanol is identical with homoarenol (2a), whose structure should be revised. The phloroglucinol-type structure of arzanol and the 1,2,4-trihydroxyphenyl-type structure of the base-induced fragmentation product of homoarenol could be reconciled in light of a retro-Fries-type fragmentation that triggers a change of the hydroxylation pattern of the aromatic moiety. On the basis of these findings, the structure of arenol, the major constituent of the clinically useful antibiotic arenarin, should be revised from 2b to 1b, solving a long-standing puzzle over its biogenetic derivation. An alpha-pyrone (micropyrone, 7), the monoterpene rac-E-omega-oleoyloxylinalol (10), four known tremetones (9a-d), and the dimeric pyrone helipyrone (8) were also obtained. Arzanol inhibited HIV-1 replication in T cells and the release of pro-inflammatory cytokines in LPS-stimulated primary monocytes, qualifying as a novel plant-derived anti-inflammatory and antiviral chemotype worth further investigation.
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| 8. |
- Appendino, G, et al.
(författare)
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Oligomeric acylphloroglucinols from myrtle (Myrtus communis)
- 2002
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Ingår i: Journal of Natural Products. - : American Chemical Society (ACS). - 0163-3864 .- 1520-6025. ; 65:3, s. 334-338
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Tidskriftsartikel (refereegranskat)abstract
- The dimeric nonprenylated acylphloroglucinol semimyrtucommulone (6) was obtained from the leaves of. myrtle (Myrtus communis) as a 2:1 mixture of two rotamers. The known trimeric phloroglucinol myrtucommulone A (1) was also isolated and characterized spectroscopically as a silylated cyclized derivative (5). Myrtucommulone A showed significant antibacterial activity against multidrug-resistant (MDR) clinically relevant bacteria, while semimyrtucommulone was less active.
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| 9. |
- Appendino, G, et al.
(författare)
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SERCA-inhibiting activity of C-19 terpenolides from Thapsia garganica and their possible biogenesis
- 2005
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Ingår i: Journal of Natural Products. - : American Chemical Society (ACS). - 0163-3864 .- 1520-6025. ; 68:8, s. 1213-1217
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Tidskriftsartikel (refereegranskat)abstract
- An investigation of Thapsia garganica afforded a series of tetracyclic C-19 dilactones, whose production was dependent on the time and location of the collection. These unusual tetrahomosesquiterpenoids are presumably biosynthesized via a carbon dioxide-triggered electrophilic polyolefin cyclization. Despite the structural differences with thapsigargin, these compounds showed SERCA-inhibiting properties.
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| 10. |
- Appendino, G, et al.
(författare)
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Structure-activity relationships of ring C-secotaxoids. 1. Acylative modifications
- 2004
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Ingår i: Journal of Natural Products. - : American Chemical Society (ACS). - 0163-3864 .- 1520-6025. ; 67:2, s. 184-188
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Tidskriftsartikel (refereegranskat)abstract
- The acylative modification of IDN 5390 (3a), a 7,8-secotaxoid under preclinical development, was investigated. A modest decrease of potency was observed upon acylation of the primary and the enolic hydroxyls, suggesting that, just like in paclitaxel, the hydroxyl groups in the upper right-hand sector are not critical for cytotoxicity. The activity of these analogues, and especially of the chemically robust carbonates 3c and 3d, makes it unlikely that the activity of IDN 5390 is due to in vivo oxidation to a fledgling 7-aldehyde and re-aldolization to the corresponding taxane derivative.
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