Undescribed Triterpenes from the Leaves of Syzygium myrsinifolium with Their α-Glucosidase and α-Amylase Inhibition Activity

Discovery of Undescribed Triterpenoids and Flavonoids From the Fruits of Syzygium attopeuense With Their α-Glucosidase and α-Amylase Inhibitory Activity

The fruits of Syzygium attopeuense were extracted and isolated by using various chromatographic methods to obtain 13 compounds (1-13). Three of them, 2α,3β,6β-trihydroxy-24-nor-urs-4(23),12,20(30)-trien-28-oic acid 28-O-β-D-glucopyranoside (1), 3β,6β,23-trihydroxyurs-12-en-28-oic acid 28-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (2), and (2R,3R)-5,7,3',4'-tetrahydroxyflavanone 3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (3) were verified by CAS SciFinder as previously undescribed compounds. Their structures were determined by using infrared, electronic circular dichroism, high-resolution-electrospray ionization-mass spectrometry, and one-dimensional and two-dimensional nuclear magnetic resonance methods. Moreover, Compounds 1, 2, 4-7, and 12 inhibited significantly α-glucosidase with minimum inhibitory concentration (IC50) values ranging from 18.3 to 147.5 µM, while compounds 1, 4, 5, and 12 significantly inhibited α-amylase with IC50 values of 98.5, 176.0, 131.6, and 184.5 µM, respectively.

Elucidating the therapeutic efficacy of polyherbal formulation for the management of diabetes through endogenous pancreatic β-cell regeneration

Diabetes mellitus is characterized by the progressive loss of pancreatic β-cells. Owing to the adverse side effects of conventional antidiabetic, ethnopharmacological agents have emerged as adjunct therapies for their management. The present study aims to validate the antidiabetic activity of an aqueous polyherbal extract (APE) via in silico, in vitro, and in vivo models. UHPLC-Q-TOF-MS and HPLC analysis of APE were performed to identify bioactive secondary plant metabolites. In silico approaches implemented to predict the binding efficacy of the active phytoconstituents. Biochemical estimation, antioxidant activity, and in vitro and in vivo antidiabetic activities of APE were performed. Histomorphological and immunohistological studies of the pancreatic islets were carried out in diabetic animals for microarchitectural study. UHPLC-Q-TOF-MS identified a total of 60 compounds in APE, of which 39 were reported to have antidiabetic activity, and 16 marker compounds were identified via high-performance liquid chromatography (HPLC). An in silico study revealed a strong interaction of verbacoside B with the target proteins. APE is characterized by high flavonoid and phenolic contents with strong antioxidant properties. In an in vitro enzymatic assay, APE significantly inhibited α-amylase and α-glucosidase enzymes, with calculated IC50 values of 54.26 ± 0.14 and 26.47 ± 0.12 μg/ml, respectively. An in vitro glucose uptake assay revealed increased uptake with APE treatment in a dose-dependent manner. APE significantly decreased blood glucose and HbA1c levels and had no side effects on liver or kidney function, as measured from blood parameters. Immunohistological observation revealed 47% regeneration of pancreatic β-cells with APE treatment in diabetic animals.

Camehakosides A-E, Five Undescribed Acylated Oleanane Saponins From the Leaves of Camellia hakodae With Their α-Glucosidase Inhibitory Activity

Five undescribed acylated oleanane saponins (1-5), together with five known compounds (6-10) were isolated from the leaves of Camellia hakodae. Their chemical structures were determined by infrared, high-resolution electrospray ionization mass spectrometry, and one-dimensional and two-dimensional nuclear magnetic resonance spectra. Compounds 1-10 significantly inhibited α-glucosidase with IC50 values ranging from 2.11 ± 0.18 to 10.42 ± 0.41 µM.

Four Undescribed Stilbenoid Derivatives from the Aerial Parts of Dendrobium officinale with their α-Glucosidase and α-Amylase Inhibitory Activity

In this study, four undescribed bibenzyl derivatives (1-4), together with seven known compounds (5-11) were isolated from the aerial parts of Dendrobium officinale. Their chemical structures were determined to be (7'S,8'S) -9''-acetyldendrocandin U (1), (7'S,8'S) -4'-methoxydendrocandin T (2), (7'R,8'S) -dendrocandin B (3), (1S,2R) -5'''-methoxydendrofindlaphenol C (4) by analyzing of the spectroscopic data including HR-ESI-MS, 1D-, and 2D-NMR spectra. The absolute configurations of compounds 1-4 were determined by the electronic circular dichroism (ECD) spectra. Compounds 1-3, 5, 10 and 11 inhibited α-glucosidase with the IC50 values ranging from 56.3 to 165.3 μM, compounds 1-3, 5, 7-10 inhibited α-amylase with the IC50 values ranging from 65.2 to 177.6 μM.

Undescribed Lignanamide and Flavone C-Glucoside Isolated from the Aerial Parts of Piper Samentosum with NO Production Inhibitory Activity in LPS Activated RAW 264.7 Cells

In this study, two undescribed compounds (1 and 2), together with eight known compounds (3-10) were isolated from the aerial parts of Piper samentosum by various chromatography methods. Their chemical structures were determined to be 7'''-oxolyciumamide N (1), vitexin 2''-O-β-D-(6'''-feruloyl)-glucopyranoside (2), 1,2-dihydro-6,8-dimethoxy-7-hydroxy-1-(3,4-dihydroxyphenyl)-N1,N2-bis-[2-(-hydroxyphenyl)ethyl]-2,3-napthalene dicarboamide (3), vitexin 6''-O-β-D-glucopyranoside (4), vitexin 2''-O-α-L-rhamnopyranoside (5), methyl 2-hydroxybenzoate-2-O-β-D-apiofuranosyl-(1→2)-O-β-D-glucopyranoside (6), ficuside G (7), methyl 2-O-β-D-glucopyranosylbenzoate (8), methyl 2,5-dihydroxybenzoate-5-O-β-D-glucopyranoside (9), and 3,7-dimethyloct-1-ene-3,6,7-triol 6-O-β-D-glucopyranoside (10) by spectroscopic data analysis including HR-ESI-MS, 1D-, and 2D-NMR spectra. Compounds 1-5 inhibited nitric oxide production in LPS-stimulated RAW264.7 macrophages with the IC50 values of 27.62, 74.03, 38.54, 70.39, and 44.95 μM, respectively. The NMR data of 9 were firstly reported herein.

Discovery of new triterpene glycosides from Dendrobium officinale with their α-glucosidase and α-amylase inhibitory activity

In this study, seven new pentacyclic triterpene glycosides, named dendrocinaosides A-G (1-7), and six known ones (8-13) were isolated from the whole plants of Dendrobium officinale. Their structures were determined by analyses of HR-ESI-MS, 1D and 2D NMR spectra. Compounds 1-4, 8, and 9 potentially inhibited α-glucosidase and α-amylase activities with the IC50 values ranging from 31.3 ± 2.2 to 42.4 ± 2.5 μM for anti α-glucosidase and from 36.5 ± 1.8 to 56.4 ± 2.0 μM for anti α-amylase activities, respectively, which were lower than that of the positive control, acarbose, showing IC50 values of 47.1 ± 1.4 μM for anti α-glucosidase and 145.7 ± 2.2 μM for anti α-amylase.