Beta,beta-Dimethylacrylalkannin

Cytotoxic naphthoquinones from Alkanna cappadocica ( perpendicular).[Pubmed: 20405844 ]

J Nat Prod. 2010 May 28;73(5):860-4.

In a continuing program to discover new anticancer agents from plants, especially naphthoquinones from the Alkanna genus, Alkanna cappadocica was investigated.
METHODS AND RESULTS:
Bioassay-guided fractionation of a dichloromethane/methanol (1:1) extract of the roots led to the isolation of four new and four known naphthoquinones. The known compounds are 11-deoxyalkannin (1), Beta,beta-Dimethylacrylalkannin (2), 11-O-acetylalkannin (3), and alkannin (4). The new compounds 5-O-methyl-11-deoxyalkannin (5), 8-O-methyl-11-deoxyalkannin (6), 5-O-methyl-11-O-acetylalkannin (7), and 5-O-methyl-Beta,beta-Dimethylacrylalkannin (8) were characterized by spectroscopic analyses (LC-ESIMS, 1D and 2D NMR). Cytotoxicity of the isolated compounds was evaluated versus 12 human cancer cell lines, HT-29, MDA-MB-231, PC-3, AU565, Hep G2, LNCaP, MCF7, HeLa, SK-BR-3, DU 145, Saos-2, and Hep 3B together with two normal cell lines, VERO and 3T3, by using the MTT assay. Compound 7 showed remarkable cytotoxicity with IC(50) values between 0.09 and 14.07 muM. It was more potent than the other compounds in six out of 12 cancer cell lines and the positive controls doxorubicin and etoposide.
CONCLUSIONS:
The mono-O-methylated alkannin derivatives and their cytotoxicities are reported for the first time.

Mol. Simulat., 2012, 38(12):980-6.

DFT study on the radical scavenging activity of β,β-dimethylacrylalkannin derivatives[Reference: WebLink]

METHODS AND RESULTS:
The radical scavenging activity of β,β-dimethylacrylalkannin(Beta,beta-Dimethylacrylalkannin) derivatives has been studied by using density functional theory. The hydrogen bond property of the studied structures was investigated using the atoms in molecules theory. It turned out that the hydrogen bond is important for good radical scavenging activity. The hydrogen atom transfer for β,β-dimethylacrylalkannin derivatives is difficult to occur compared with the zero compound phenol. However, β,β-dimethylacrylalkannin derivatives appear to be good candidates for the one-electron transfer, particularly for β,β-dimethylacrylalkannin derivatives with electron-donating groups. Their naphthoquinone planar conformation and the extended electronic delocalisation between adjacent substituent groups determine low adiabatic ionisation potential (IP) values.
CONCLUSIONS:
The IPvalues of β,β-dimethylacrylalkannin derivatives with –NHPh, –N(CH)Ph, –N(CHCH)O and –N(CH)groups are lower than that of the parent compound β,β-dimethylacrylalkannin, suggesting that these derivatives are expected to be the promising candidates for radical scavenging activity compounds. Taking this system as an example, we present an efficient method for the investigation of radical scavenging activity from theoretical point of view.