Functional New Acylated Sophoroses and Deglucosylated Anthocyanins in a Fermented Red Vinegar

Abstract

The new acylated polyphenols were isolated from a red-colored vinegar produced via fermentation with purple-fleshed sweet potato storage roots, and identified mainly by MS and NMR. The three acylated sophoroses were determined as 6-O-(E)-caffeoyl-(2-O-(6-O-acyl)-beta-d-glucopyranosyl)-d-glucopyranoses, where acyl was (E)-caffeoyl, p-hydroxybenzoyl, and (E)-feruloyl, respectively. The four acylated anthocyanins were also determined as cyanidin 3-O-(6-O-(E)-caffeoyl-(2-O-(6-O-(E)-feruloyl)-beta-d-glucopyranosyl)-beta-d-glucopyranoside), in addition to peonidin 3-O-(6-O-(E)-caffeoyl-(2-O-(6-O-acyl)-beta-d-glucopyranosyl)-beta-d-glucopyranosides), where acyl was (E)-caffeoyl, p-hydroxybenzoyl, and (E)-feruloyl, respectively. The diacylated sophoroses showed higher antioxidant capacity than that of monoacylated analogue 6-caffeoylsophorose, so the multiacylation established to enhance their antioxidant capacity. Similarly, 5-deglucosylated anthocyanins also gave somewhat stronger antioxidation than corresponding sweet potato anthocyanins. In rat intestinal alpha-glucosidase inhibition study, the diacylated sophoroses preferably inhibited maltase rather than sucrase with an IC(50) value of <300 microM, indicating a potential role as antidiabetic phytochemicals. These acylated polyphenols in a red vinegar were expected to play important functional roles for health.

Isolation and identification of two major acylated anthocyanins from purple sweet potato (Ipomoea batatas L. cultivar Eshu No. 8) by UPLC‐QTOF‐MS/MS and NMR

“…According to the previous reports of the heteronuclear multiple‐bond correlation (HMBC) and nuclear overhauser effect spectroscopy (NOESY) (Terahara et al ., ), interglycosidic linkage was β‐G 3b ‐(1→2)‐G 3a of a sophorose because G 3b was linked on the G 3a ‐2OH based on the glycosylation shifts of δ G 3a ‐2H 4.36‐4.38 and δ G 3a ‐2C 82.51–82.72 ppm (Table ). Sophorose is always linked to C3 position of aglycon (most are cyanidin and peonidin).…”

“…In the recent report, Terahara et al . identified the structure of acylated 5‐deglucosylated anthocyanins through fermentation with purple sweet potato in 2009 (Terahara et al ., ). Montilla et al .…”

“…In the previous study, the anthocyanins from purple sweet potato (Eshu No. 8) have been identified as cyanidin or peonidin 3-sophoroside-5-glucoside based and acylated with one or two phenolic acid, such as caffeic acid, phydroxybenzoic acid and ferulic acid on the 3sophorosy moiety (Terahara et al, 2009). According to the previous report of our laboratory (Zhang et al, 2015(Zhang et al, , 2017Wang et al, 2017;Luo et al, 2018), peonidin 3-caffeoyl-p-hydroxybenzoyl sophoroside-5glucoside and peonidin 3-caffeoyl-feruloyl sophoroside-5-glucoside are two major anthocyanins from purple sweet potato.…”

Dietary anthocyanin‐rich plants: Biochemical basis and recent progress in health benefits studies

“…In their results, purple potato-derived acylated anthocyanins were shown to inhibit a-glucosidase activity [51,52]. This same group also studied the inhibitory effects acylated anthocyanins on the elevation of blood glucose levels in rats [53], and found that the molecular structure responsible for a-glucosidase inhibition was not anthocyanidin itself, but caffeoylsophorose, which is a component of the acylated anthocyanin molecule [54][55][56]. Caffeoylsophorose can be absorbed in vivo in an intact form and subsequently produces caffeic acid and its conjugate [57].…”

Anthocyanins as Functional Food Factors— Chemistry, Nutrition and Health Promotion —

“…A famous anecdote about the effect of anthocyanins on vision in Japan describes Royal Air Force pilots during World War II who experienced enhanced vision in the dark α-glucosidase in the small intestinal endothelium, which in turn inhibits degradation and absorption of carbohydrates, thereby ameliorating hyperglycemia. Glycosides, such as C3G, are generally very weak inhibitors of α-glucosidase (Iwai et al, 2006), except for acylated anthocyanins (Matsui et al, 2001a(Matsui et al, , 2001b(Matsui et al, , 2002Terahara et al, 2003Terahara et al, , 2009 and Matsui et al (2004) revealed that caffeoylsophorose (CS), a component of acylated anthocyanins, is the molecular structure responsible for this strong inhibitory activity. Since CS is absorbed in an intact form to produce caffeic acid and its conjugates (Qiu et al, 2011), it is possible that absorbed CS or its metabolites exert an anti-diabetic effect via pathways that do not include α-glucosidase inhibition.…”