Enzymatic transformation of platycosides and one‐step separation of platycodin D by high‐speed countercurrent chromatography

Abstract

Platycosides, the saponins found in the roots of Platycodon grandiflorum (Platycodi Radix), are typically composed of oleanane triterpenes with two side chains. In platycosides, platycodin D, a glucose unit at C-3, is a major component, which has several pharmacological activities. Because of the high demand for this compound, we attempted to enzymatically convert platycodin D(3) and platycoside E, having two and three glucose units at C-3, respectively, into platycodin D. In this study, we tested the ability of several glycosidases to transform platycosides, or more specifically, the ability to transform platycoside E and platycodin D(3) into platycodin D. To obtain pure platycodin D on a preparative scale, high-speed countercurrent chromatography with a solvent system of ethyl acetate/n-butanol/water (1.2:1:2, v/v/v) was used for the separation of the enzymatically transformed product. Approximately 39.4 mg of platycodin D (99.8% purity) was obtained from 200 mg of the product in a one-step separation. The results strongly support the advantage of enzymatic transformation of the platycosides for the efficient enrichment of platycodin D in the complicated extract of the medicinal plant.

Preparative separation of minor saponins from Platycodi Radix by high‐speed counter‐current chromatography

“…According to our previous report [22], the PS-enriched fraction from Platycodi Radix by T. reesei was enzymatically transformed to obtain an enhanced amount of platycodin D, which is one of the major bioactive components. Platycodin D and deapio-platycodin D, the major components of PS_cel, were first separated by HSCCC with the two-phase solvent system of ethyl acetate-n-butanol-water at a volume ratio of 1.2:1:2.…”

“…The 70% methanol fraction containing the PSenriched fraction was evaporated, lyophilized and stored in a desiccator until further processing. The enzymatically transformed product (PS_cel) was prepared according to our previous report [22]. The reaction mixture containing PS (1 g) and cellulase (200 units) in pH 5 sodium acetate buffer was incubated at 37.51C for 24 h in a shaking incubator, then placed in a water bath at 901C to stop the reaction.…”

“…The 100% methanol fraction was evaporated, lyophilized and stored in a desiccator until use. PS_cel was used to obtain the minor saponin fraction by HSCCC separation with ethyl acetate-n-butanol-water in a volume ratio of 1.2:1:2 [22].…”

Simultaneous RP-HPLC Determination of Six Platycosides: Application to an Enzymatic Preparation Study

“…When comparing with mild acid hydrolysis, alkali treatment and microbial conversion, enzymatic preparation through sugar hydrolysis at the C-3 position of platycosides possess a decisive advantage of shorter reaction time and mild reaction condition [9,12]. Recently, snailase (a complex of cellulase, hemicellulase, pectinase and b-glucuronidase), extracted from the digestive tract of snails, have received increasing attention due to strong hydrolysis ability [13].…”

“…Among these platycosides, deapio-platycodin D (dPD) and platycodin D (PD), as a major platycosides and marker reference substances, exhibited strong cytotoxicity against tumor cell lines and can be implemented as a therapeutic agent for the treatment of cancers [5][6][7][8]. Therefore, production of dPD and PD would be very important and many studies have been aimed at separation and preparation of these two platycosides [9][10][11].…”