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Triterpenoids are responsible for various biological activities in several traditional Chinese herbal medicines [1]. These molecules contain both aglyone and sugar moieties, and their biological actions are determined by the type of aglycone as well as the number and arrangement of sugars in the attached side chains [1,2]. For example, mogrosides, a group of triterpenoids produced by Siraitia grosvenorii (Lo-Han-Kuo, LHK), exemplify how sugar moiety differences affect sweetness. The relative sweetness of mogroside VI (MG VI), mogroside V (MG V), 11-oxo-mogroside V (11-oxo-MGV), mogroside IV(MG IV), siamenoside I (S–I) and mogroside III (MG III) were measured to be 125, 378, 68, 300, 465 and 195 times sweeter than sucrose, respectively [2–4]. However, mogroside II (MG II) and mogroside I (MG I) are tasteless [2,3]. In addition to the flavor of the molecules, other biochemical activities are also influenced by the different sugar moieties. For example, the maltase inhibitory activity (IC50) of MG V, MG IV, S–I, and MG III were 14, 12, 10, and 1.6 mM, respectively, while the aglycone mogrol (MG) did not inhibit the enzyme [5]. Moreover, Mogroside I E (MG I E) was shown to inhibit human promyelocytic leukemia cell (HL-60) growth, whereas MG V, MG III, mogroside II E (MG II E), mogroside I A1 (MG I A1), and MG did not prevent cancer cell growth [6]. Although there is no apparent consistency among mogrosides in terms of specific biological activities, the number of glucose and glycosidic linkage patterns can explain performance in sweetness, maltase inhibition, and anticancer activities.
Recently, several studies have found that the main triterpene glycosides in herbal medicines are deglycosylated by human intestinal bacteria to enrich minor components with good anticancer activity and low side effects after oral administration [7–9]. As a result, several researchers have studied the production of minor components through acid hydrolysis, enzymatic conversion, and intestinal bacteria transformation [10–12]. These studies have enabled workers to obtain suitable amounts of compounds for further investigations into their biological activities [7,13]. It has become apparent that compared to acid or alkaline hydrolysis, enzymatic reactions are often the most reliable methods to obtain specifically modified glycosides of triterpenoids. MG V is the...