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Isolation and Characterisation of (5 R , 6 S ,5′ R ,8′ R )‐ and (5 R ,6 S ,5′ R ,8′ S )‐Luteochrome from Brazilian Sweet Potatoes ( Ipomoea batatas L AM .)
Author(s) -
de Almeida Ligia Bicudo,
De Vuono Camargo Penteado Marilene,
Simpson Kenneth L.,
Britton George,
Acemoglu Murat,
Eugster Conrad Hans
Publication year - 1986
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19860690705
Subject(s) - chemistry , stereochemistry , ipomoea , carotenoid , ring (chemistry) , high performance liquid chromatography , botany , organic chemistry , food science , biology
Luteochrome isolated from the tubers of a white‐fleshed variety of sweet potato ( Ipomoea batatas L AM .) has been shown by HPLC, 1 H‐NMR and CD spectra to consist of a mixture of (5 R ,6 S ,5′ R ,8′ R )‐ and (5 R ,6 S ,5′ R ,8′ S )‐ 5,6:5′,8′‐diepoxy‐5,6,5′,8′‐tetrahydro‐β,β‐carotene ( 1 and 2 , resp.). Therefore, its precursor is (5 R ,6 S ,5′ R ,6′ S )‐5,6:5′,6′‐diepoxy‐5,6,5′,6′‐tetrahydro‐β,β‐carotene ( 4 ). This is the first identification of luteochrome as a naturally occurring carotenoid and, at the same time, gives the first clue to the as yet unknown chirality of the widespread β,β‐carotene diepoxide. These facts demonstrate that the enzymic epoxidation of the β‐end group occurs from the α‐side, irrespective of the presence of OH groups on the ring.