- Chemical and Biochemical Modifications of Parthenin
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Parthenin, a medicinally important natural sesquiterpenoid and a potent allelochemical underwent different regio- and stereoselective modifications to several interesting analogues by chemical and biochemical means. The compound was treated with various common reducing agents including NaBH4, NaBH4/I2, Na/EtOH, Mg/MeOH and Zn/HOAc as well as with different oxidizing agents including m-CPBA and dilute HCl under different reaction conditions. The retention of the α-methylene-γ-lactone moiety which plays a vital role for bioactivity of the compound was observed in some of the reaction products. The microwave irradiation of the compound afforded anhydroparthenin as the only product. Baker's yeast reduction of parthenin was investigated for the first time and yielded the naturally occurring dihydrocoronopilin. - Keywords: parthenin, sesquiterpenoid, α-methylene-γ-lactone, chemical modifications, baker's yeast reduction.
- Das, Biswanath,Venkataiah, B.,Kashinatham, A.
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p. 6585 - 6594
(2007/10/03)
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- Synthesis and cytotoxicity of water-soluble ambrosin prodrug candidates
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The potential therapeutic application of the naturally occurring, cytotoxic pseudoguaianolide sesquiterpene lactone ambrosin is limited by its aqueous insolubility. A number of water-soluble ambrosin derivatives have therefore been prepared for potential use as prodrugs. Michael addition of several secondary amines to both the α,β-unsaturated ketone and α- methylene lactone moieties of ambrosin afforded tertiary amine diadducts that were converted to water-soluble hydrochloride salts. The salt of the bis- piperidine adduct proved to be the most potent, producing cytotoxic activity only slightly less potent than that of ambrosin itself in a variety of human cancer cell cultures. The sodium salt of the bis-sulfonic acid derivative of ambrosin was inactive, while the sodium salt of the bis-sulfonic acid analog had low activity. Biological evaluation of several ambrosin analogs with reduced and/or isomerized α,β-unsaturated ketone and α-methylene lactone moieties demonstrated the importance of both of these functional groups for biological activity.
- Hejchman,Haugwitz,Cushman
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p. 3407 - 3410
(2007/10/02)
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- Enantioselective synthesis of neoambrosin, parthenin, and dihydroisoparthenin
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Enantioselective synthesis of the titled ambrosanolides is described. Use of the trimethylsilyl group as an anchor contributed to the stereoselective introduction of two methyl groups.
- Asaoka, Morio,Ohkubo, Taketoshi,Itahana, Hirotsune,Kosaka, Takatoshi,Takei, Hisashi
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p. 3115 - 3128
(2007/10/02)
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