Coumarins, Fatty Acids, Volatile and Non-volatile Terpenoids from the Leaves of Citrus aurantium L. (Sour Orange) and Citrus sinensis (L.) Osbeck (Sweet Orange)

Abstract

Coumarins including psoralens were isolated and identified from the

leaves of Citrus aurantium var. amara L. (sour orange) and Citrus sinensis

L. Osbeck (sweet orange). Five coumarins (aurapten, auraptene, limettin,

umbelliferone and osthol) and two coumarins of the psoralen type (bergapten

and bergaptol) were obtained from the leaf extract of sour orange

while only bergaptol was extracted from the leaf extract of the sweet

orange. Although these compounds were previously isolated from roots

and fruit peels, this is the first report of these coumarins from the leaves

of either species. Twenty six terpenoids plus apiol were obtained from the

volatile and non-volatile residues of the extracts, and four of these constituents,

apiole, stigmasterol, β-sitosterol and friedelin are reported here

to be isolated for the first time from the leaves of these citrus species. Five

fatty acids were obtained from the leaves, linoleic, oleic, linolenic, palmitic

and palmitoleic and the first two are the major constituents.