Three resin glycosides isolated from Argyreia acuta, including two isomers.

In the present study, three compounds were isolated from Argyreia acuta, among them, compounds 1 and 2 were new and Compounds 1 and 3 were isomers. They were separated by several types of columns, such as normal phase, RP, size exclusion and preparative HPLC, and their structures were elucidated by several spectroscopic methods, such as 1D- and 2D-NMR and HR-TOF-MS.

Four Pentasaccharide Resin Glycosides from Argyreia acuta.

Four pentasaccharide resin glycosides, acutacoside F-I (1-4), were isolated from the aerial parts of Argyreia acuta. These compounds were characterized as a group of macrolactones of operculinic acid A, and their lactonization site of 11S-hydroxyhexadecanoic acid was esterified at the second saccharide moiety (Rhamnose) at C-2. The absolute configuration of the aglycone was S. Their structures were elucidated by established spectroscopic and chemical methods.

Trimer procyanidin oligomers contribute to the protective effects of cinnamon extracts on pancreatic ß-cells in vitro.

AIM: Cinnamon extracts rich in procyanidin oligomers have shown to improve pancreatic ß-cell function in diabetic db/db mice. The aim of this study was to identify the active compounds in extracts from two species of cinnamon responsible for the pancreatic ß-cell protection in vitro. METHODS: Cinnamon extracts were prepared from Cinnamomum tamala (CT-E) and Cinnamomum cassia (CC-E). Six compounds procyanidin B2 (cpd1), (-)-epicatechin (cpd2), cinnamtannin B1 (cpd3), procyanidin C1 (cpd4), parameritannin A1 (cpd5) and cinnamtannin D1 (cpd6) were isolated from the extracts. INS-1 pancreatic ß-cells were exposed to palmitic acid (PA) or H2O2 to induce lipotoxicity and oxidative stress. Cell viability and apoptosis as well as ROS levels were assessed. Glucose-stimulated insulin secretion was examined in PA-treated ß-cells and murine islets. RESULTS: CT-E, CC-E as well as the compounds, except cpd5, did not cause cytotoxicity in the ß-cells up to the maximum dosage using in this experiment. CT-E and CC-E (12.5-50 µg/mL) dose-dependently increased cell viability in both PA- and H2O2-treated ß-cells, and decreased ROS accumulation in H2O2-treated ß-cells. CT-E caused more prominent ß-cell protection than CC-E. Furthermore, CT-E (25 and 50 µg/mL) dose-dependently increased glucose-stimulated insulin secretion in PA-treated ß-cells and murine islets, but CC-E had little effect. Among the 6 compounds, trimer procyanidins cpd3, cpd4 and cpd6 (12.5-50 µmol/L) dose-dependently increased the cell viability and decreased ROS accumulation in H2O2-treated ß-cells. The trimer procyanidins also increased glucose-stimulated insulin secretion in PA-treated ß-cells. CONCLUSION: Trimer procyanidins in the cinnamon extracts contribute to the pancreatic ß-cell protection, thus to the anti-diabetic activity.

Two pentasaccharide resin glycosides from Argyreia acuta.

Two new compounds of acutacosides 1 and 2, pentasaccharide resin glycosides were isolated from the aerial parts of Argyreia acuta. The core of the two compounds was operculinic acid A, and they were esterfied at the same position, just one substituent group was linked at C-2 of Rha. The absolute configuration of the aglycone in the two compounds was established by Mosher's method, which was (11S)-hydroxyhexadecanoic acid (jalapinolic acid). Their structures were established by a combination of spectroscopic and chemical methods.

New Isoprenylated Phenolic Compounds from Morus laevigata.

Two new isoprenylated flavonoids, laevigasins A and B (1 and 2, resp.), and one new isoprenylated 2-arylbenzofuran, leavigasin C (3), together with eight known compounds, 4-11, were isolated from the twigs of Morus laevigata. Their structures were elucidated by spectroscopic methods. Laevigasin A (1) showed significant inhibitory effect on α-glucosidase in vitro. Notabilisin E (5), taxifolin (10), and hultenin (11) inhibited PTP1B phosphatase activity in vitro.

Triterpenoids and α-glucosidase inhibitory constituents from Salacia hainanensis.

Thirteen triterpenoids (1-13), including two new lupane triterpenoids, salacinins A and B (1 and 2), as well as one new friedelane triterpenoid, salacinin C (3), were isolated from the roots and stems of Salacia hainanensis. The structures of new compounds were elucidated by extensive spectroscopic analysis including 1D and 2D NMR, and MS experiments. Compound 1 possesses rare 2,3-seco-lupane skeleton. Compounds 4, 6 and 7 showed inhibitory effects on α-glucosidase in vitro.

Pentasaccharide resin glycosides from Ipomoea pes-caprae.

Pescapreins XXI-XXX (1-10), pentasaccharide resin glycosides, together with the known pescapreins I-IV and stoloniferin III were isolated from the aerial parts of Ipomoea pes-caprae (beach morning-glory). The pescapreins are macrolactones of simonic acid B, partially esterified with different fatty acids. The lactonization site of the aglycone, jalapinolic acid, was located at C-2 or C-3 of the second saccharide moiety. Their structures were established by a combination of spectroscopic and chemical methods. Compounds 1-10 were evaluated for their potential to modulate multidrug resistance in the human breast cancer cell line MCF-7/ADR. The combined use of these new compounds at a concentration of 5 µg/mL increased the cytotoxicity of doxorubicin by 1.5-3.7-fold.

[A new anthraquinone from the root of Lasianthus acuminatissimus].

To study the constituents from the chloroform extract of the roots of Lasianthus acuminatissimus Merr., various chromatographic techniques were used to separate and purify the constituents. The structure was established on the basis of ID, 2D NMR and HRMS spectroscopic analysis. A new compound was isolated and identified, which was 3, 8-dihydroxy-1-methoxy-2-methoxymethyl-9,10-anthraquinone (I). Compound I is a new anthraquinone, namely lasianthurin.