Hepatoprotective Phenolic Glycosides from Gymnema tingens

Abstract

Six new phenolic diglycosides, named gymnetinosides A-F (1-6), were isolated from the ethanolic extract of Gymnema tingens, together with three known diglycosides, sequinoside K (7), khaephuoside B (8), and albibrissinoside A (9). The structures of the new compounds were determined by spectroscopic techniques including 1D-, 2D NMR, mass spectroscopy, and circular dichroism. Compounds 1, 5, and 6 showed hepatoprotective activities against D-galactosamine-induced HL-7702 cell damage.

Hepatoprotective benzofurans and furanolignans fromGymnema tingens

“…Hepatoprotective compounds of various structural types were documented in the literature, such as sesquiterpene glycosides [19], phenolic glycosides [12,20], iridoid glycosides [21,22], lignans [23], triterpenes [24], and triterpene saponins [25]. The identification of two new hepatoprotective benzofurans (1 -2) in this study has enriched the chemical diversity of the hepatoprotective compounds.…”

“…In a previous investigation of the hepatoprotective constituents of G. tingens, we had identified nine bioactive phenolic diglycosides [12]. In continuation of this work, two benzofurans (1-2) and six furanoligans (3 -8) with hepatoprotective effect were isolated ( Figure 1).…”

“…To the best of our knowledge, phytochemical investigation on G. tingens had been so far reported only by our group [12]. In a previous investigation of the hepatoprotective constituents of G. tingens, we had identified nine bioactive phenolic diglycosides [12].…”

“…As reported previously, the EtOAc extract of the ethanol extract of G. tingens was subjected to vacuum liquid chromatography over silica gel to yield 22 fractions, among which fraction 9 was found to be a pool of nine phenolic diglycosides [12]. The less polar fraction 6 (15 g) was subjected to chromatography over ODS eluting with a gradient of methanol -water (from 60% to 100%) to obtain 12 subfractions (F6-1 -F6-12).…”

“…In Chinese folk medicine, the extract of Gymnema has the effect of detumescence, detoxicating, promoting granulation, and easing pain [3]. Secondary metabolites including saponins, steroids, alkaloids, phenolic glycosides, and peptides have been reported from Gymnema inodorum [4], Gymnema sylvestre [5], Gymnema yunnanense [6,7], Gymnema alternifolium [8][9][10][11], and Gymnema tingens [12], and showed interesting biological activities such as antisweet, antidiabetic, antiallergic, antiviral, hepatoprotective, and lipid lowering effects.…”