Jingya Ruan

Anti-inflammatory steroids from the rhizomes of Dioscorea septemloba Thunb.

Seven new steroid glycosides, dioscorosides A1 (1), A2 (2), B1 (3), B2 (4), C1 (5), C2 (6), and D (7), together with 22 known ones (8-29) were isolated from the rhizomes of Dioscorea septemloba, their structures were elucidated by chemical and spectroscopic methods. All isolates were evaluated for in vitro anti-inflammatory potential using LPS-stimulated RAW 264.7 murine macrophages. Among them, spirostane glycosides 18 and 21-24 exhibited significant inhibition of nitrite production. Moreover, the structure-activity relationship was summarized.

Oleanane type saponins from the stems of Astragalus membranaceus (Fisch.) Bge. var. mongholicus (Bge.) Hsiao

Astragalus membranaceus is a Traditional Chinese Medicine (TCM) belonging to the Leguminosae family. It has been used as antidiabetic, cardioprotective, and hepatoprotective in the TCM clinic. From the stems of A. membranaceus (Fisch.) Bge. var. mongholicus (Bge.) Hsiao, 14 oleanane type saponins (1-14) including eight new ones, astroolesaponins A (1), B (2), C1 (3), C2 (4), D (5), E1 (6), E2 (7), and F (8) were obtained, and their structures were elucidated by chemical and spectroscopic methods. Compounds 1-5, 7, 8, 11, and 13 showed decreased effects on triglyceride levels in sodium oleate induced HepG2 cells.

Inhibitory Effects of Constituents from the Aerial Parts of Rosmarinus officinalis L. on Triglyceride Accumulation

Sixteen flavonoids (1–16) including two new ones, named officinoflavonosides A (1) and B (2) were obtained from the aerial parts of Rosmarinus officinalis. Among the known ones, 6, 10, and 13 were isolated from the rosmarinus genus for the first time. Their structures were elucidated by chemical and spectroscopic methods. Moreover, the effects on sodium oleate-induced triglyceride accumulation (TG) in HepG2 cells of the above-mentioned compounds and 16 other isolates (17–32) reported previously to have been obtained in the plant were analyzed. Results show that eight kinds of flavonoids (compounds 1, 2, 3, 6–9 and 11) and seven kinds of other known isolates (compounds 17–20, 23, 26 and 31) possessed significant inhibitory effects on intracellular TG content in HepG2 cells. Among them, the activities of compounds 1 and 20 were comparable to that of orlistat, which suggested that these compounds in this plant might be involved in lipid metabolism.

Bioactive gentixanthone and gentichromone from the whole plants of Gentianella acuta (Michx.) Hulten.

Five new compounds, gentixanthones A1 (1), A2 (2), and gentichromones A1-A3 (3-5), together with thirteen known xanthones (6-18) were obtained from the whole plants of Gentianella acuta (Michx.) Hulten. Their structures were elucidated by chemical and spectroscopic methods. Among them, compounds 6, 8, 13, 14, and 17 were obtained from Gentianella genus firstly, and 7, 12, 15, 16, and 18 were isolated from this plant for the first time. Meanwhile, inhibitory effects of 1-18 on motility of mouse isolated intestine tissue were determined. As results, xanthones 1, 2, 6, 7, 9, 10 and 14 were found to have significant reduce effect on intestine contraction tension, and structure-activity relationship was discussed.

Bioactive constituents from the rhizomes of Dioscorea septemloba Thunb

Eight new compounds, dioscorosides G (1), H1 (2), H2 (3), dioscorol B (4), dioscorosides I (5), J (6), K1 (7), and K2 (8), together with twelve known ones (9-20) were obtained from the rhizomes of Dioscorea septemloba. Their structures were elucidated by chemical and spectroscopic methods. Among the known isolates, 12-14, 18, and 20 were isolated from the Dioscoreae genus for the first time. While, 9-11, 15, and 16 were firstly obtained from the plant. Moreover, all the isolates were evaluated for in vitro anti-inflammatory potential using LPS-stimulated RAW 264.7 murine macrophages, and compounds 7, 11, 15, and 16 were found to display significant inhibition of nitrite production.

Spirostane-Type Saponins Obtained from Yucca schidigera

It is well known that spirostane-type saponins show various bioactivities. In our on-going program of screening these kinds of constituents from natural products, Yucca schidigera was found to be rich in them, and nine new spirostanol saponins, Yucca spirostanosides A1 (1), A2 (2), B1 (3), B2 (4), B3 (5), C1 (6), C2 (7), C3 (8), and D1 (9), together with five known ones (10–14) were isolated from the plant. Their structures were elucidated by extensive spectroscopic methods, including 1D and 2D NMR and MS spectra, and comparing with published data.

Eudesmane-Type Sesquiterpene Glycosides from Dictamnus dasycarpus Turcz.

Eudesmane-type sesquiterpenes have been reported to exhibit varieties of biological activities. During the process of investigating this kind of natural product from the root bark of Dictamnus dasycarpus Turcz., 13 eudesmane-type sesquiterpene glycosides including six new isolates, named as dictameudesmnosides A1 (1), A2 (2), B (3), C (4), D (5), and E (6), together with seven known ones (7–13), were obtained. Herein, their structures were determined by the analysis of physical data, spectroscopic analysis, and chemical methods. The existence of α-configuration glucose units in their structures (1–5, 8) is not very common in natural glycosidic components. Meanwhile, compounds 3–5, 7, and 9–13 displayed TG accumulation inhibitory effects on HepG2 cells.

Mangiferin Improves Hepatic Lipid Metabolism Mainly Through Its Metabolite-Norathyriol by Modulating SIRT-1/AMPK/SREBP-1c Signaling

Objective: Mangiferin (MGF) is a natural xanthone, with regulation effect on lipid metabolism. However, the molecular mechanism remains unclear. We purposed after oral administration, MGF is converted to its active metabolite(s), which contributes to the effects on lipid metabolism. Methods: KK-Ay mice were used to validate the effects of MGF on lipid metabolic disorders. Liver biochemical indices and gene expressions were determined. MGF metabolites were isolated from MGF administrated rat urine. Mechanism studies were carried out using HepG2 cells treated by MGF and its metabolite with or without inhibitors or small interfering RNA (siRNA). Western blot and immunoprecipitation methods were used to determine the lipid metabolism related gene expression. AMP/ATP ratios were measured by HPLC. AMP-activated protein kinase (AMPK) activation were identified by homogeneous time resolved fluorescence (HTRF) assays. Results: MGF significantly decreased liver triglyceride and free fatty acid levels, increased sirtuin-1 (SIRT-1) and AMPK phosphorylation in KK-Ay mice. HTRF studies indicated that MGF and its metabolites were not direct AMPK activators. Norathyriol, one of MGF’s metabolite, possess stronger regulating effect on hepatic lipid metabolism than MGF. The mechanism was mediated by activation of SIRT-1, liver kinase B1, and increasing the intracellular AMP level and AMP/ATP ratio, followed by AMPK phosphorylation, lead to increased phosphorylation level of sterol regulatory element-binding protein-1c. Conclusion: These results provided new insight into the molecular mechanisms of MGF in protecting against hepatic lipid metabolic disorders via regulating SIRT-1/AMPK pathway. Norathyriol showed potential therapeutic in treatment of non-alcoholic fatty liver disease.

Chemical and Biological Research on Herbal Medicines Rich in Xanthones

Xanthones, as some of the most active components and widely distributed in various herb medicines, have drawn more and more attention in recent years. So far, 168 species of herbal plants belong to 58 genera, 24 families have been reported to contain xanthones. Among them, Calophyllum, Cratoxylum, Cudrania, Garcinia, Gentiana, Hypericum and Swertia genera are plant resources with great development prospect. This paper summarizes the plant resources, bioactivity and the structure-activity relationships (SARs) of xanthones from references published over the last few decades, which may be useful for new drug research and development on xanthones.

Bioactive Constituents Obtained from the Seeds of Lepidium apetalum Willd

Three new compounds, apetalumosides C1 (1), D (2), and 1-thio-β-d-glucopyranosyl(1→1)-1-thio-α-d-glucopyranoside (3), together with twenty-two known ones (4–25) were obtained from the seeds of Lepidium apetalum Willd. Among the known isolates, 5–8, 10–13, 16–20, and 25 were obtained from the genus for the first time; 4, 14, 15, and 21–24 were isolated from the species for the first time. Meanwhile, the NMR data of 16 was first reported here. Their structures were determined by means of chemical and spectroscopic methods. On the other hand, their inhibitory effects on sodium oleate-induced triglyceride (TG) overloading in HepG2 cells were evaluated. As a result, two new compounds (1 and 2), together with known isolates 7–11, 13, 14, 16–18, 20, 21, and 25 possessed significant inhibitory effects in the cells.