Cytotoxic Hydroazulene Diterpenes from the Brown Alga Dictyota dichotoma

2003 ◽  
Vol 58 (1-2) ◽  
pp. 17-22 ◽  
Author(s):  
Sahar R. Gedara ◽  
Osama B. Abdel-Halim ◽  
Saleh H. El-Sharkawy ◽  
Osama M. Salama ◽  
Thomas W. Shier ◽  
...  

Two new hydroazulenoid (prenyl guaiane) diterpenes, dictyone acetate (2) and 3,4-epoxy 13-hydroxy pachydictyol A (4) were isolated from the petroleum ether fraction of the alcoholic extract of the brown alga, Dictyota dichotoma (Hudson) Lamouroux, which was collected from the Red Sea coasts at Hurgada, Egypt, together with three known ones, pachydictyol A (1), dictyone (3) and 11-hydroxypachydictyol A (dictyol E) (5). In addition, the steroidal compound, stigmasta-5,(E)-24(28)-dien-3-β-ol (fucosterol) (6) was also isolated. The structures of the isolated compounds have been determined on the basis of spectroscopic evidences as well as physical and chemical correlation with known compounds. Compounds 1, 2, 3 and 5 showed moderate cytotoxic activity

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Amina El-Shaibany ◽  
Molham AL-Habori ◽  
Tareq Al-Maqtari ◽  
Hassan Al-Mahbashi

The aim of this study was to investigate the anticancer and antioxidant activities as well as the safety of the brown algae Dictyota dichotoma of the Western seacoast of Yemen. Cytotoxicity of methanol extract of D. dichotoma and several of its fractions, petroleum ether, chloroform, ethyl acetate, n-butanol, and aqueous extracts against seven different cancer cell lines was determined by crystal violet staining. The antioxidant activity was also assessed using the DPPH radical scavenging assay. Acute toxicity study was performed on rats at increasing doses of the methanol extract. Extracts of D. dichotoma exerted a significant dose-dependent cytotoxicity on the seven tumor cell lines but were generally more selective on MCF-7 and PC-3. Among all fractions, the chloroform fraction of the D. dichotoma displayed the highest cytotoxic activity and was most effective in MCF-7, PC3, and CACO cells (IC50 = 1.93 ± 0.25, 2.2 ± 0.18, and 2.71 ± 0.53 μg/mL, respectively). The petroleum ether fraction was also effective, particularly against MCF-7 and PC-3 (IC50 = 4.77 ± 0.51 and 3.93 ± 0.51 μg/mL, respectively) whereas the activity of the ethyl acetate fraction was more pronounced against HepG2 and CACO (IC50 = 5.06 ± 0.21 and 5.06 ± 0.23 μg/mL, respectively). Of all the extracts tested, the crude methanolic extract of the algae exhibited only a modest antioxidant potential (IC50 = 204.6 ± 8.3 μg/mL). Doses as high as 5000 mg/kg body weight of D. dichotoma methanolic extracts were safe and well tolerated by rats. The overall results showed that D. dichotoma exhibited a significant cytotoxic activity probably due to the occurrence of nonpolar cytotoxic compounds, which is independent of its antioxidant capability.


2003 ◽  
Vol 58 (1-2) ◽  
pp. 23-32 ◽  
Author(s):  
Sahar R. Gedara ◽  
Osama B. Abdel-Halim ◽  
Saleh H. El-Sharkawy ◽  
Osama M. Salama ◽  
Thomas W. Shier ◽  
...  

The aerial parts of Fagonia boveana afforded two new erythroxane-type diterpenes, 3β, 15, 16-trihydroxy-erythrox-4(18)-ene (2) and 15, 16-dihydroxy-cis-ent-erythrox-3-ene (fagonene) (3) together with two known ones; 16-O-acetylfagonone (1) and 7β-hydroxy fagonene (8). Also a new guaiane sesquiterpene alcohol, 6,10-epoxy-4α-hydroxy guaiane type sesquiterpene (4) has been isolated In addition three 8-methoxy flavonols, 8-methoxy-quercetin-3, 7, 3′-trimethyl ether (ternatin) (5), gossypetin, 3, 8, 3′, 4′ tetramethyl ether (6) and herbacetin- 3, 8-dimethyl ether (7) were also isolated. The structures of the isolated compounds have been determined on the basis of spectroscopic evidences as well as physical and chemical correlation with known compounds. On performing different assays for biological activities, 6 displayed significant cytotoxic activity against KA3IT and NIH3T3 cell lines, 8 was the most active antiviral against Herpes simplex type 1 while 7 was the most active cancer-preventive agent using protein-tyrosine kinase inhibitory method


2016 ◽  
Vol 30 (10) ◽  
pp. 1672-1679 ◽  
Author(s):  
Renping Liu ◽  
Enwei Tao ◽  
Shuwen Yu ◽  
Bo Liu ◽  
Lingman Dai ◽  
...  

2016 ◽  
Vol 36 (10) ◽  
pp. 1059-1070 ◽  
Author(s):  
MBO Chagas ◽  
NCC Cordeiro ◽  
KMR Marques ◽  
MG Rocha Pitta ◽  
MJBM Rêgo ◽  
...  

A series of new thiazacridine agents were synthesized and evaluated as antitumor agents, in terms of not only their cytotoxicity but also their selectivity. The cytotoxicity assay confirmed that all compounds showed cytotoxic activity and selectivity. The new compound, 3-acridin-9-ylmethyl-5-(5-bromo-1 H-indol-3-ylmethylene)-thiazolidine-2,4-dione (LPSF/AA29 – 7a), proved to be the most promising compound as it presents lower half-maximal inhibitory concentration (IC50) values (ranging from 0.25 to 68.03 µM) depending on cell lineage. In HepG2 cells, the lowest IC50 value was exhibited by 3-acridin-9-ylmethyl-5-(4-piperidin-1-yl-benzylidene)-thiazolidine-2,4-dione (LPSF/AA36 – 7b; 46.95 µM). None of the synthesized compounds showed cytotoxic activity against normal cells (IC50 > 100 µM). The mechanism of death induction and cell cycle effects was also evaluated. Flow cytometric analysis revealed that the compounds LPSF/AA29 – 7a and LPSF/AA36 – 7b significantly increased the percentage of apoptotic cells and induced G2/M arrest in the cell cycle progression. Therefore, these new thiazacridine derivatives constitute promising antitumor agents whose cytotoxicity and selectivity properties indicate they have potential to contribute to or serve as a basis for the development of new cancer drugs in the future.


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