3 ',5 '-di-C-beta-glucopyranosylphloretin, a flavonoid characteristic of the genus Fortunella

Dihydrochalcone derivative, 3',5'-di-C-beta -glucopyranosylphloretin (1), i s present in the genus Fortunella, (F. crassifolia, F. japonica, F. margari ta, F. polyandra and F. hindsii). These species accumulate a large quantity of 1 in their fruits (peel, 6.5-15.2 mg/g in dry wt; juice sac, 1.5-10.5 m g/g) and in their leaves (21.3-60.2 mg/g). Twenty-seven Tanaka's Citrus spe cies examined lack 1, but C, madurensis and C. halimii contain 1 in large q uantities in their peels (25.1 and 33.6 mg/g) and juice sacs (4.1 and 4.2 m g/g). Poncirus species do not contain 1. For Fortunella-citrus hybrids, the Orangequat [C. unshiu x F. crassifolia], the Thomasville citrangequat [For tunella sp. x (C, sinensis x Poncirus trifoliata)], and seven hybrid progen ies [F. margarita x C. junos], contain large amounts of 1 in their peels (1 7.0-7.9 mg/g) and juice sacs (2.0-9.9 mg/g). These facts suggest that accum ulation of 1 is a generic trait of the genus Fortunella and that the inheri tance of the trait among the intergeneric hybrids is controlled by a domina nt allele. Thus C, madurensis and C. halimii are thought to originate from natural hybrids between the genera Citrus and Fortunella. Phloridzin, which has the same aglycon as 1, was not detected in the citrus plants examined. (C) 2001 Elsevier Science Ltd. All rights reserved.