- Synthesis and inhibitory activities against colon cancer cell growth and proteasome of alkylresorcinols
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We have identified alkylresorcinols (ARs) as the major active components in wheat bran against human colon cancer cell growth (HCT-116 and HT-29) using a bioassay-guided approach. To further study the structure-activity relationships, 15 ARs and their intermediates (1-15) were synthesized expediently by the modified Wittig reaction in aqueous media, and six 5-alkylpyrogallols and their analogues (16-21) were prepared by the general Grignard reaction. The synthetic AR analogues were evaluated for activities against the growth of human colon cancer cells HCT-116 and HT-29 and the chymotrypsin-like activity of the human 20S proteasome. Our results found that (1) AR C13:0 and C15:0 (13 and 14) had the greatest inhibitory effects in human colon cancer cells HCT-116 and HT-29, while decreasing or increasing the side chain lengths diminished the activities; (2) two free meta-hydroxyl groups at C-1 and C-3 on the aromatic ring of the AR analogues greatly contributed to their antitumor activity; (3) the introduction of a third hydroxyl group at C-2 (20 and 21) into the aromatic ring of the AR analogues yielded no significant enhancement in activity against HCT-116 cells and decimated the effects against HT-29 cells, but dramatically increased the activity against the chymotrypsin-like activity of the human 20S proteasome; and (4) AR C11:0 (12) was found to have the greatest effect in a series of AR C9:0-C17:0 against the chymotrypsin-like activity of the human 20S proteasome.
- Zhu, Yingdong,Soroka, Dominique N.,Sang, Shengmin
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p. 8624 - 8631
(2012/11/13)
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- Alkylresorcylic acid synthesis by type III polyketide synthases from rice Oryza sativa
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Alkylresorcinols, produced by various plants, bacteria, and fungi, are bioactive compounds possessing beneficial activities for human health, such as anti-cancer activity. In rice, they accumulate in seedlings, contributing to protection against fungi. Alkylresorcylic acids, which are carboxylated forms of alkylresorcinols, are unstable compounds and decarboxylate readily to yield alkylresorcinols. Genome mining of the rice Oryza sativa identified two type III polyketide synthases, named ARAS1 (alkylresorcylic acid synthase) and ARAS2, that catalyze the formation of alkylresorcylic acids. Both enzymes condensed fatty acyl-CoAs with three C2 units from malonyl-CoA and cyclized the resulting tetraketide intermediates via intramolecular C-2 to C-7 aldol condensation. The alkylresorcylic acids thus produced were released from the enzyme and decarboxylated non-enzymatically to yield alkylresorcinols. This is the first report on a plant type III polyketide synthase that produces tetraketide alkylresorcylic acids as major products.
- Matsuzawa, Miku,Katsuyama, Yohei,Funa, Nobutaka,Horinouchi, Sueharu
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experimental part
p. 1059 - 1067
(2011/03/20)
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- An expedient synthesis of 5-n-alkylresorcinols and novel 5-n-alkylresorcinol haptens
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The first synthesis of bioactive long alkyl chain 5-n-alkylresorcinols, present in whole grain products, by a novel modification of the Wittig reaction is described. All the main long chain 5-n-alkylresorcinols present in rye and wheat, including C23 and C25 analogues and haptens, which have not been previously prepared, were synthesised. Microwave-promoted reactions of a semistabilized ylid and alkanals in water gave good yields in both pressurized and open systems. An alternative microwave-promoted synthesis starting from non-stabilized alkyltriphenylphosphonium salts and 3,5-dimethoxybenzaldehyde worked as well. Aqueous media were suitable for the reactions even if the starting materials were not soluble in water. The 5-n-alkylresorcinols are potential biomarkers of whole grain intake, and the new hapten derivatives of 5-n-alkylresorcinols will open the way for the immunochemical detection techniques of alkylresorcinols.
- Parikka, Kirsti,Waehaelae, Kristiina
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supporting information; experimental part
(2010/04/22)
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