α-Glucosidase inhibitory caged xanthones from the resin ofGarcinia hanburyi

Abstract

A yellow resin (gamboge) from Garcinia hanburyi has been widely used as folk medicine due to its antibacterial and antitumor activities. We isolated four α-glucosidase inhibitory compounds from the methanol extract of gamboge. The compounds (1-4) were identified as gambogoic acid (1), moreollic acid (2), gambogic acid (3), and 10-methoxygambogenic acid (4), respectively through spectroscopic data including 2D-NMR and HREIMS. All compounds were examined in the enzyme inhibition assay against α-glucosidase to identify their inhibitory potencies and kinetic behavior. All compounds (1-4) showed enzyme inhibition against α-glucosidase, but the activity was significantly affected by the methoxy group on C-10 of ring A and pentenyl pyran moiety of ring D. For example, compound 1 (IC 50 =41.4 μM) bearing pyran ring eight times effective that 4 (IC 50 =350.6 μM) having geranyl group itself. Most active compound was found out to be gambogoic acid (1) which was analyzed most abundant metabolite in gamboge by LC-ESI-MS/MS. In kinetic study, compounds 1 and 2 were proved as noncompetitive inhibitors.

Ultrasound-assisted extraction of emodin from Rheum officinale Baill and its antibacterial mechanism against Streptococcus suis based on CcpA

“…Generally, α -glucosidase is an indispensable enzyme in the glycogen metabolic pathway of microorganisms and plays an important role in the normal life of bacteria [48] . As shown in Fig.…”

“…The inhibitory effect of emodin on α -glucosidase activity was detected by recording absorbance changes due to the conversion of PNPG to p -nitrophenol [48] . Briefly, S. suis cells (1 × 10 6 CFU/mL) were collected by centrifuging at 12000 × g for 2 min, and then suspended in PBS (pH 7.4) to obtain the OD 600 of 1.0.…”

Structural diversity and biological activities of caged Garcinia xanthones: recent updates

“…Only a small number of caged xanthones have been tested for potential bioactivity beyond anticancer effects. Moreollic acid, 10-methoxygambogenic acid, gambogoic acid, morellic acid, gambogenic acid and 93 have been found to competitively inhibit (IC 50 = 0.47-6.6 µM) protein tyrosine phosphatase 1B (PTP1B) [37,151], an important modulator of insulin signaling, and a potential target for the treatment of cancer and obesity [152][153][154], These compounds, along with 51-54, 71, 10a-hydroxygambogic acid, desoxymorellin, gambogin, gambogellic acid and desoxygambogenin, also exhibit inhibitory activity against a-glucosidase [34,155].…”