Oleanane-Type Triterpene Glycosides from Camellia phanii and Their α-Glucosidase Inhibitory Activity.

Three new oleanane-type triterpene saponins, named camphanosides A-C (1-3), along with five known compounds, chikusetsusaponin IVa (4), spinasaponin A 28-O-glucoside (5), (-)-epicatechin (6), (-)-epicatechin 3-O-gallate (7), and (-)-epigallocatechin 3-O-gallate (8) were isolated from the leaves Camellia phanii Hakoda & Ninh. Their structures were established by 1D and 2D-NMR and mass spectral analysis and chemical methods. Moreover, compounds 1-5 were also evaluated for α-glucosidase inhibitory activity. Compounds 1-3 exhibited moderate α-glucosidase inhibitory activity with IC50 values of 230.7±18.0, 251.4±22.7, and 421.4±25.6 µM, respectively.

Polypyrrole-based nanocomposites doped with both salicylate/molybdate and graphene oxide for enhanced corrosion resistance on low-carbon steel.

In this work, polypyrrole-based nanocomposites doped with graphene oxide, molybdate, and salicylate (PPy/GO/Mo/Sal) were synthesized via in situ electrochemical polymerization to enhance the anti-corrosion protection performance of polymer coatings. The morphology and structures of the coatings were characterized by SEM, EDX, FTIR, Raman spectroscopy, and XRD. The protection abilities of coatings against corrosion were investigated in 0.1 M NaCl solution with EIS potentiodynamic polarization, salt spray test, and open-circuit potential (OCP) measurements. The results showed that with the presence of both molybdate/salicylate and GO in the PPy matrix, the nanocomposite coating exhibited an excellent protection ability against corrosion for low-carbon steel, better than that with only GO as filler. Compared to the nanocomposites doped with only salicylate or salicylate/GO, the one doped with both molybdate/salicylate and GO exhibited the longest protection plateau (ca. 100 h) on the OCP-time curves with some fluctuation points known as the self-healing action of molybdate dopant. It also resulted in a decrease in the corrosion current (Tafel plots), a higher impedance (Bode plot), and a better protection performance in salt spray tests. In this case, the anti-corrosion ability of the coatings was provided through a barrier and self-healing mechanism.

Achyranbidens A-C: three new compounds from Achyranthes bidentata Blume.

Phytochemical study on the roots of Achyranthes bidentata Blume led to the isolation of sixteen compounds including three new ones (1-3). Their chemical structures were determined as oleanolic acid 28-O-ß-D-glucopyranoside-3-O-[ß-D-glucopyranosyl-(1→3)-ß-D-galactopyranoside) (1), methyl (8Z,11Z)-5,6,7-trihydroxytetradeca-8,11-dienoate (2), methyl (6E,11Z)-5,8,9-trihydroxytetradeca-6,11-dienoate (3), fulgidic acid (4), (9E,11E)-13-oxooctadeca-9,11-dienoic acid (5), (9Z,11E,15Z)-13-hydroxyoctadeca-9,11,15-trienoic acid (6), oleanolic acid 28-O-ß-D-glucopyranoside-3-O-α-L-rhamnopyranosyl-(1→4)-ß-D-glucuronopyranoside (7), oleanolic acid 28-O-ß-D-glucopyranoside-3-O-ß-D-glucopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→3)]-ß-D-glucuronopyranoside (8), oleanolic acid 3-O-ß-D-glucopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→3)]-ß-D-glucuronopyranoside (9), oleanolic acid 3-O-α-L-rhamnopyranosyl-(1→3)-ß-D-glucuronopyranoside (10), blumenol C glucoside (11), citroside A (12), 6S,9S-roseoside (13), ginsenoside Rg1 (14), 20-hydroxyecdysone (15), and benzyl α-L-rhamnopyranosyl-(1→6)]-ß-D-glucopyranoside (16) by spectroscopic analysis. Compounds 1, 7 and 11-16 inhibited NO production in LPS-activated RAW264.7 cells with IC50 values in the range from 28.03 to 54.23 µM (positive control, L-NMMA: IC50 = 35.52 µM). Compounds 14 and 15 showed anti α-glucosidase activity with IC50 values of 176.24 and 156.92 µM, respectively, compared with the positive control, acarbose, IC50 = 160.99 µM.

Constituents of Tinospora sinensis and their nitric oxide inhibitory activities.

One new phenylpropanoid glycoside, tinosinen A (1) and 13 known compounds, tinosinen (2), citrusin B (3), picraquassioside C (4), erythro-guaiacylglycerol-ß-O-4'-coniferyl alcohol (5), erythro-guaiacylglycerol-8-O-4'-(sinapyl alcohol) ether (6), erythro-syringylglycerol-8-O-4'-(sinapyl alcohol) ether (7), seco-isolariciresinol 9-O-D-ß-glucopyranoside (8), tinosposide A (9), pinoresinol-4'-O-ß-D-glucopyranoside (10), syringaresinol-4'-O-ß-D-glucopyranoside (11), pinoresinol (12), syringaresinol (13), and lirioresino-ß-dimethyl ether (14) were isolated from the stems of Tinospora sinensis (Lour.) Merr. Their structures were established by detailed spectroscopic studies and comparisons with those reported in the literature. Compound 13 showed significant inhibitory NO production (IC50 value of 38.53 ± 1.90 µM) in RAW264.7 macrophages, LPS-stimulated. Compounds 3-7, 11, 12, and 14 inhibited NO production with IC50 values ranging from 38.53 to 99.07 µM.

One new furostane saponin from Allium ramosum and lipid accumulation inhibitory activity.

A new furostane saponin, ramosaponin (1), and four known furostane saponins, protodioscin (2), dehydrotomatoside (3), (25 R)-26-O-(ß-D-glucopyranosyl)-furost-5-ene-3ß,22α,26-triol 3-O-ß-D-glucopyranosyl-(1→4)-ß-D-galactopyranoside (4), and anguivioside A (5) were isolated from the methanol extract of Allium ramosum seeds. Their structures were identified based on spectroscopic evidence and comparison with those reported in the literature. All compounds were evaluated for reduction of lipid accumulation in HepG2 cell line. As a result, compound 1 showed significant lipid accumulation inhibitory activity with an IC50 value of 64.32 ± 3.87 µM.

Chemical constituents from Schisandra sphenanthera and their cytotoxic activity.

Extensive phytochemical investigation of Schisandra sphenanthera leaves resulted in the isolation of six highly oxygenated nortriterpenoids (1-6) and five lignans (7-11) including a new pre-schisanartane-type, schisandrathera A (1), a new dibenzocyclooctadiene glycoside, schisandrathera B (7) and two new lignans, schisandrathera C (8) and schisandrathera D (9). Their chemical structures including absolute configurations were determined extensively by means of HR-ESI-MS, NMR, and ECD spectra. In addition, all isolated compounds were tested for cytotoxic activity against PC3 (prostate cancer) and MCF7 (breast cancer) cell lines. Among these compounds, schirubrisin B (3) showed strong cytotoxic effect on both PC3 and MCF7 cell lines with IC50 values of 3.21 ± 0.68, 13.30 ± 0.68 µM, respectively, whereas ten remaining compounds were found to be less effective in the investigated models.