scholarly journals Rifamycin W Analogues from Amycolatopsis mediterranei S699 Δrif-orf5 Strain

Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 920
Author(s):  
Yanrong Shi ◽  
Feng Ye ◽  
Yuliang Song ◽  
Xiaochun Zhang ◽  
Chunhua Lu ◽  
...  

Rifamycin W, the most predominant intermediate in the biosynthesis of rifamycin, needs to undergo polyketide backbone rearrangement to produce rifamycin B via an oxidative cleavage of the C-12/C-29 double bond. However, the mechanism of this putative oxidative cleavage has not been characterized yet. Rif-Orf5 (a putative cytochrome P450 monooxygenase) was proposed to be involved in the cleavage of this olefinic moiety of rifamycin W. In this study, the mutant strain Amycolatopsis mediterranei S699 Δrif-orf5 was constructed by in-frame deleting the rif-orf5 gene to afford thirteen rifamycin W congeners (1–13) including seven new ones (1–7). Their structures were elucidated by extensive analysis of 1D and 2D NMR spectroscopic data and high-resolution ESI mass spectra. Presumably, compounds 1–4 were derivatized from rifamycin W via C-5/C-11 retro-Claisen cleavage, and compounds 1–3, 9 and 10 featured a hemiacetal. Compounds 5–7 and 11 showed oxygenations at various sites of the ansa chain. In addition, compounds 1–3 exhibited antibacterial activity against Staphylococcus aureus with minimal inhibitory concentration (MIC) values of 5, 40 and 0.5 µg/mL, respectively. Compounds 1 and 3 showed modest antiproliferative activity against HeLa and Caco-2 cells with half maximal inhibitory concentration (IC50) values of about 50 µM.

Biomolecules ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1265
Author(s):  
Feng Ye ◽  
Yanrong Shi ◽  
Shengliang Zhao ◽  
Zhiying Li ◽  
Haoxin Wang ◽  
...  

Proansamycin X, a hypothetical earliest macrocyclic precursor in the biosynthesis of rifamycin, had never been isolated and identified. According to bioinformatics analysis, it was proposed that RifT (a putative NADH-dependent dehydrogenase) may be a candidate target responsible for the dehydrogenation of proansamycin X. In this study, the mutant strain Amycolatopsis mediterranei S699 ΔrifT was constructed by deleting the rifT gene. From this strain, eleven 8-deoxy-rifamycin derivatives (1–11) and seven known analogues (12–18) were isolated. Their structures were elucidated by extensive analysis of 1D and 2D NMR spectroscopic data and high-resolution ESI mass spectra. Compound 1 is a novel amide N-glycoside of seco-rifamycin. Compounds 2 and 3 feature conserved 11,12-seco-rifamycin W skeleton. The diverse post-modifications in the polyketide chain led to the production of 4–11. Compounds 2, 3, 5, 6, 13 and 15 exhibited antibacterial activity against Staphylococcus aureus (MIC (minimal inhibitory concentration) values of 10, 20, 20, 20, 40 and 20 μg/mL, respectively). Compounds 14, 15, 16, 17 and 18 showed potent antiproliferative activity against KG1 cells with IC50 (half maximal inhibitory concentration) values of 14.91, 44.78, 2.16, 18.67 and 8.07 μM, respectively.


Marine Drugs ◽  
2019 ◽  
Vol 17 (3) ◽  
pp. 167 ◽  
Author(s):  
Pierre-Eric Campos ◽  
Emmanuel Pichon ◽  
Céline Moriou ◽  
Patricia Clerc ◽  
Rozenn Trépos ◽  
...  

Chemical study of the CH2Cl2-MeOH (1:1) extract of the sponge Fascaplysinopsis reticulata collected in Mayotte highlighted three new tryptophan derived alkaloids, 6,6′-bis-(debromo)-gelliusine F (1), 6-bromo-8,1′-dihydro-isoplysin A (2) and 5,6-dibromo-8,1′-dihydro-isoplysin A (3), along with the synthetically known 8-oxo-tryptamine (4) and the three known molecules from the same family, tryptamine (5), (E)-6-bromo-2′-demethyl-3′-N-methylaplysinopsin (6) and (Z)-6-bromo-2′-demethyl-3′-N-methylaplysinopsin (7). Their structures were elucidated by 1D and 2D NMR spectra and HRESIMS data. All compounds were evaluated for their antimicrobial and their antiplasmodial activities. Regarding antimicrobial activities, the best compounds are (2) and (3), with minimum inhibitory concentration (MIC) of 0.01 and 1 µg/mL, respectively, towards Vibrio natrigens, and (5), with MIC values of 1 µg/mL towards Vibrio carchariae. In addition the known 8-oxo-tryptamine (4) and the mixture of the (E)-6-bromo-2′-demethyl-3′-N-methylaplysinopsin (6) and (Z)-6-bromo-2′-demethyl-3′-N-methylaplysinopsin (7) showed moderate antiplasmodial activity against Plasmodium falciparum with IC50 values of 8.8 and 8.0 µg/mL, respectively.


Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2577 ◽  
Author(s):  
Hongjing Dong ◽  
Yanling Geng ◽  
Xueyong Wang ◽  
Xiangyun Song ◽  
Xiao Wang ◽  
...  

One new monoterpene glycoside (1), one new phenyl glycoside (2), one new caffeoyl derivative (3), were isolated from Scindapsus officinalis (Roxb.) Schott., along with four known compounds (4–7). Structures of the isolated compounds were elucidated by extensive analysis of spectroscopic data, especially 2D NMR data and comparison with literatures. All isolates were evaluated for anti-inflammatory activity against nitric oxide (NO) production in vitro. Compounds 3 and 7 exhibited moderate inhibitory effects on NO production with IC50 values of 12.2 ± 0.8 and 18.9 ± 0.3 μM, respectively.


Molecules ◽  
2019 ◽  
Vol 24 (12) ◽  
pp. 2339 ◽  
Author(s):  
Bomi Nam ◽  
Seung Mok Ryu ◽  
Dongho Lee ◽  
Chan-Hun Jung ◽  
Chang Hyun Jin ◽  
...  

Two new phenanthrenes, (1R,2R)-1,7-hydroxy-2,8-methoxy-2,3-dihydrophenanthrene-4(1H)-one (1) and 2,7-dihydroxy-phenanthrene-1,4-dione (2), were isolated from the ethyl acetate-soluble fraction of Dendrobii Herba, together with seven known phenanthrenes (3–9), two bibenzyls (10–12), and a lignan (13). Structures of 1 and 2 were elucidated by analyzing one-dimensional (1D) and two-dimensional (2D)-NMR and High-resolution electrospray ionization mass spectra (HR-ESI-MS) data. The absolute configuration of compound 1 was confirmed by the circular dichroism (CD) spectroscopic method. In cytotoxicity assay using FaDu human hypopharynx squamous carcinoma cell line, compounds 3–6, 8, 10, and 12 showed activities, with IC50 values that ranged from 2.55 to 17.70 μM.


2016 ◽  
Vol 14 (2) ◽  
pp. 139-145 ◽  
Author(s):  
Matthias Onyebuchi Agbo ◽  
Kenneth Maduabuchi Ezealisiji ◽  
Joshua Elijah Parker ◽  
Francis Ikechukwu Ukekwe ◽  
Wilfred Ofem Obonga

Semi-preparative High Liquid Column Chromatographic separation of the ethyl acetate soluble fraction of a methanol extract of the leaves of Loranthus micranthus Linn. parasitic on Hevea brasiliensis (Willd. ex A. Juss.) led to the isolation of two gallic acid derivatives (1-2). The structures of the compounds were solved by using spectroscopic methods (1D and 2D NMR and mass spectroscopic data) as well as by comparison with literature values. The compounds were identified as 3,4,5-tri-O-methyl gallic acid (1) and methyl 3-O-methyl gallate (2). The antioxidant activity of the isolated compounds was evaluated by using DPPH assay. Compounds 1 and 2 showed strong antioxidative capacity with inhibitory concentration (IC50) values of 10.0 ± 0.03 and 45.0 ± 0.02 ?M, respectively.Dhaka Univ. J. Pharm. Sci. 14(2): 139-145, 2015 (December)


2019 ◽  
Vol 16 (6) ◽  
pp. 474-477 ◽  
Author(s):  
Pham Van Khang ◽  
Nguyen Thi Hien Lan ◽  
Le Quang Truong ◽  
Mai Thi Minh Chau ◽  
Mai Xuan Truong ◽  
...  

In this report, two new steroidal glycosides were isolated and determined from n-butanol fraction of A.asphodeloides. The structures were confirmed in comparison with the spectral data of known compounds by using different spectroscopic analysis approaches including 1D & 2D-NMR techniques and HRMS. The anti-proliferation screening against cancer cell lines A549 and HeLa indicated that compound 1 exhibited good inhibitory activities with IC50 values of 0.79 and 0.55 µg/mL, respectively.


Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 305
Author(s):  
Guangyuan Luo ◽  
Li Zheng ◽  
Qilin Wu ◽  
Senhua Chen ◽  
Jing Li ◽  
...  

Six new fusarin derivatives, fusarins G–L (1–6), together with five known compounds (5–11) were isolated from the marine-derived fungus Fusarium solani 7227. The structures of the new compounds were elucidated by means of comprehensive spectroscopic methods (1D and 2D NMR, HRESIMS, ECD, and ORC) and X-ray crystallography. Compounds 5–11 exhibited potent anti-inflammatory activity by inhibiting the production of NO in RAW264.7 cells activated by lipopolysaccharide, with IC50 values ranging from 3.6 to 32.2 μM. The structure–activity relationships of the fusarins are discussed herein.


2021 ◽  
Vol 16 (2) ◽  
pp. 1934578X2199334
Author(s):  
Do Thi Trang ◽  
Bui Huu Tai ◽  
Dan Thuy Hang ◽  
Pham Hai Yen ◽  
Phan Thi Thanh Huong ◽  
...  

Seven compounds (1-7) were isolated from the marine sponge Aaptos aaptos living in the Vietnamese sea. Their structures were determined as 2 hours, 5 H,7 H,9 H-9 S-hydroxy-imidazo[1,5- α]pyridine-1,3-dione (1), 3-([9-methylhexadecyl]oxy)propane-1,2-diol 2, 2,3-dihydro-2,3-dioxoaaptamine (3), indol-3-aldehyde (4), methyl indole-3-carboxylate (5) 4-hydroxy-5-(indole-3-yl)−5-oxo-pentan-2-one (6), and thymidine (7) by extensive analysis of HR-ESI-MS, 1D, and 2D NMR spectral data, as well as by comparison of the spectral data with those reported in the literature. In addition, the absolute configuration of 1 was determined from the experimental ECD spectrum and comparison of this with the theoretical ECD calculations using the TDDFT method. Compounds 1 and 2 were isolated from nature for the first time. Compound 3 induced cytotoxic activity against SK-LU-1, MCF-7, HepG2, and SK-Mel-2 cell lines with IC50 values of 41.27 ± 2.63, 40.70 ± 2.65, 34.31 ± 3.43, and 36.63 ± 1.40 µM, respectively.


Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 333
Author(s):  
Raha Orfali ◽  
Shagufta Perveen ◽  
Muhammad Farooq Khan ◽  
Atallah F. Ahmed ◽  
Mohammad A. Wadaan ◽  
...  

The new asperorlactone (1), along with the known illudalane sesquiterpene echinolactone D (2), two known pyrones, 4-(hydroxymethyl)-5-hydroxy-2H-pyran-2-one (3) and its acetate 4, and 4-hydroxybenzaldehyde (5), were isolated from a culture of Aspergillus oryzae, collected from Red Sea marine sediments. The structure of asperorlactone (1) was elucidated by HR-ESIMS, 1D, and 2D NMR, and a comparison between experimental and DFT calculated electronic circular dichroism (ECD) spectra. This is the first report of illudalane sesquiterpenoids from Aspergillus fungi and, more in general, from ascomycetes. Asperorlactone (1) exhibited antiproliferative activity against human lung, liver, and breast carcinoma cell lines, with IC50 values < 100 µM. All the isolated compounds were also evaluated for their toxicity using the zebrafish embryo model.


2021 ◽  
Vol 25 ◽  
Author(s):  
Na Liu ◽  
Meina Song ◽  
Yulin Sun ◽  
Fengying Yang ◽  
Haina Yu ◽  
...  

: One new eudesmane sesquiterpene (1) and one new chromolaevane sesquiterpene (2), along with 19 known compounds, have been isolated from the invasive plant Solidago canadensis. Their structures were established by spectroscopic means including 1D/2D-NMR and HR-ESIMS analyses. Compounds 10 and 12, in combination with fluconazole, showed significant activity in an in vitro synergistic antifungal assay against Candida albicans, with FIC values of <0.15625 and <0.28125, respectively. Meanwhile, the allelopathic effects of these sesquiterpenes on Arabidopsis seed germination were also tested. Compounds 5, 7, 17 and 18 retarded the seed germination of Arabidopsis with IC50 values ranging from 9.1 to 41 μg/mL, while other compounds showed no obvious inhibitory effects.


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