Prunus x yedoensis: In Vitro Culture and the Production of Flavonoids

Abstract

Prunus is a large and valuable genus of the north temperate zone. It is divided into five sections, Cerasus, Padus, Amygdalus, Prunophora, and Laurocerasus. The Prunus species valuable for flowers are P. jamasakura Sieb., ex Koidz. (P. serrulata auct., non Lindl.) and P. × yedoensis Matsum. belonging to the section Cerasus, both species being well known as Japanese flowering cherry as an ornamental rather than a fruit tree (Fig. 1). The latter is a hybrid of P. lannesiana (Carr.) Wilson var. speciosa (Koidz.) Makino and P. pendula Maxim. forma ascendens (Makino) Ohwi and most commonly planted throughout Japan. P. × yedoensis is also a valuable timber tree and the extract of bark is used for a cough remedy and an expectorant, and traditionally popular in Japan are pickled cherry blossom, and also a bean paste rice-cake wrapped in a cherry leaf, in which the flavor given is due to the presence of coumarin. On the cherry species valuable for fruits, e.g., P. avium L., Ivanička and Pre ová (1986) have reported investigation into propagation and in vitro cultures. All of the Prunus species contain a large amount of different flavonoids (Hegnauer 1973), and 13 kinds of flavonoids including flavanones, flavones and catechins, and leucoanthocyanidins are reported to be present in the wood of P. × yedoensis (Hasegawa and Shirato 1952). Recently (Ishikura et al. 1989), mature leaf flavonoids were identified as 5,4′-dihydroxy-7-methoxyisoflavone 4′-O-glucoside (prunetrin, P1), 5,7,3′,4′-tetrahydroxyflavonol 3-O-glucoside (isoquercitrin, P2), catechin (P3), epicatechin (P4), cyanidin 3-O-monoglucoside (chrysanthemin, P9), and procyanidin B-1 (P5), B-2 (P6), B-3 (P7), and B-4 (P8) (Fig. 2) (Ishikura 1972). Furthermore, we succeeded in callus induction and establishment of the cell cultures by using young shoots of P. × yedoensis, and also showed that the flavonoid compounds found in mature leaves were also present in the red cell culture (Ishikura et al. 1989). In this chapter our work on flavonoid production in cell cultures of Prunus × yedoensis is summarized.