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Volumn 19, Issue 16, 2009, Pages 4814-4817

Esters of betulin and betulinic acid with amino acids have improved water solubility and are selectively cytotoxic toward cancer cells

Author keywords

Apoptosis; Betulin; Betulinic acid; Cytotoxicity

Indexed keywords

AMINO ACID DERIVATIVE; BETULIC ACID; BETULIN; ESTER DERIVATIVE;

EID: 67651100837     PISSN: 0960894X     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.bmcl.2009.06.046     Document Type: Article
Times cited : (94)

References (17)
  • 9
    • 67651099452 scopus 로고    scopus 로고
    • note
    • 4 solvent was removed. Subsequent column chromatography on silica gel using eluents mixture chloroform/ethyl acetate (4/1) give desired compounds (in the case of betulin some of the disubstituted products were isolated). Whether to obtain disubstituted betulin derivatives exactly same protocol was applied, but 4 molar excess of the Boc-amino acid and CDI was used toward betulin. In case of the small side chains of amino acids (Gly, Ala) this allows to obtain only disubstituted derivatives, whereas in the case of more bulky substituents mixture of mono- and disubstituted derivatives was obtained. Reaction time in this case was 48 h. Their separation was achieved using above eluent system.
  • 10
    • 67651103310 scopus 로고    scopus 로고
    • note
    • We have found that application of the 25% TFA in dichloromethane or 3 M HCl in MeOH results in the partial decomposition of the compounds or/and formation of unidentified side products. Compounds after deprotection were suspended in diethyl ether, sonicated and filtered. It allows removing of all unreacted Boc protected derivatives as they are very well soluble in ether.
  • 12
    • 67651096464 scopus 로고    scopus 로고
    • note
    • Cell cytotoxicity sulforhodamine B (SRB) assay: SRB method was used for the toxicity screening of all compounds to adherent cells in a 96-well format, based on the measurement of cellular protein content. After an incubation period for 24 h, cell monolayers were fixed with 50% (wt/vol) trichloroacetic acid for 1 h in 4 °C and subsequently washed (five times) in a cold water and desiccated. Cells staining was carried out using 0.4% SRB in 1% acetic acid for 30 min in room temperature. After incubation, excess of the dye was removed by repeatedly washing (four times) with 1% (vol/vol) acetic acid. Plates were desiccated and the protein-bound dye was dissolved in 10 mM Tris base (pH 10.5) solution for absorbance determination at 562 nm using a microplate reader (Tecan, Infinite M200).
  • 16
    • 67651125427 scopus 로고    scopus 로고
    • note
    • 2 for 20 min, and then silver staining was performed. For scoring the comet pattern, 100-200 nuclei on each slide were counted and assigned to a category of apoptotic or normal cells.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.