Surface-Enhanced Raman Spectroscopy Analysis of Astragalus Saponins and Identification of Metabolites After Oral Administration in Rats by Ultrahigh-Performance Liquid Chromatography/Quadrupole Time-of-Flight Mass Spectrometry Analysis.

Astragalus mongholicus Bunge (Fabaceae) is an ancient Chinese herbal medicine, and Astragalus saponins are the main active components, which have a wide range of biological activities, such as immunomodulation, antioxidation, and neuroprotection. In this study, silver nanoparticles obtained by sodium borohydride reduction were used as the enhanced substrate to detect astragaloside I (1), astragaloside II (2), astragaloside III (3), astragaloside IV (4), isoastragaloside I (5), and isoastragaloside II (6) in the phloem, xylem, and cork by surface-enhanced Raman spectroscopy (SERS). In the SERS spectrum of Astragalus slices, the characteristic peaks were observed at 562, 671, 732, 801, 836, 950, 1,026, 1,391, and 1,584 cm-1, among which 950 cm-1 and 1,391 cm-1 were strong SERS signals. Subsequently, the metabolites of the six kinds of Astragalus saponins were identified by UPLC/ESI/Q-TOF-MS. Totally, 80, 89, and 90 metabolites were identified in rat plasma, urine, and feces, respectively. The metabolism of saponins mainly involves dehydration, deacetylation, dihydroxylation, dexylose reaction, deglycosylation, methylation, deacetylation, and glycol dehydration. Ten metabolites (1-M2, 1-M11, 2-M3, 2-M12, 3-M14, 4-M9, 5-M2, 5-M17, 6-M3, and 6-M12) were identified by comparison with reference standards. Interestingly, Astragalus saponins 1, 2, 5, and 6 were deacetylated to form astragaloside IV (4), which has been reported to have good pharmacological neuroprotective, liver protective, anticancer, and antidiabetic effects. Six kinds of active Astragalus saponins from different parts of Astragalus mongholicus were identified by SERS spectroscopy. Six kinds of active Astragalus saponins from different parts of Astragalus mongholicus were identified by SERS spectrum, and the metabolites were characterized by UPLC/ESI/Q-TOF-MS, which not only provided a new method for the identification of traditional Chinese medicine but also provided a theoretical basis for the study of the pharmacodynamic substance basis of Astragalus mongholicus saponins.

A new isoflavone glycoside from flowers of Pueraria Montana var. lobata (Willd.) Sanjappa & Pradeep.

A new isoflavone glycoside, named 3'-hydroxytectorigenin-7-O-ß-D-xylosyl-(1→6)-ß-D-glucopyranoside (1) was isolated from the flowers of Pueraria montana var. lobata (Willd.) Sanjappa & Pradeep. The structure of compound 1 was characterised by HR-ESI-MS and NMR spectroscopic methods. In radical scavenging activity test using 2, 2-diphenyl-1-picrylhydrazyl (DPPH), compound 1 showed moderate activity with IC50 value of 42 ± 4.2 µg/mL.

Comparison of antifungal activity of essential oils from different plants against three fungi.

The antifungal activity of plant essential oils (EOs) extracted by steam distillation from seven different species (Cinnamon, Anise, Clove, Citronella, Peppermint, Pepper, and Camphor) was investigated. Three common fungi were isolated from moldy wheat bread, which were identified as Aspergillus niger, A. oryzae, and A. ochraceus. The antifungal activity of anise, peppermint, clove, cinnamon, pepper, citronella, and camphor EOs from seven different spices was confirmed by agar diffusion assay against three fungi. Among all the EOs, the cinnamon EO showed the highest antifungal activity for all the fungi strains with the largest inhibition zone at the concentration of 800 mg/mL and lowest MIC ranging from 0.0625 to 0.125 mg/mL, followed by clove EO. The remaining EOs exerted moderate inhibitory effects. Further research indicated the substantial inhibitory activities of cinnamon and clove EOs on mycelial growth and spore germination in a dose-dependent manner. Further, the in vivo inhibitory activity of selected EOs on naturally infected bread demonstrated that cinnamon and clove EOs can as be used as natural antifungal agents.

Methyl protodioscin from Polygonatum sibiricum inhibits cervical cancer through cell cycle arrest and apoptosis induction.

Methyl protodioscin (MPD) is a steroid saponin which has been well known for its pharmacological properties. Herein, we evaluated the anti-cancer activity of MPD for proliferation inhibition and apoptosis induction in Hela cells. MPD was purified from the rhizoma of Polygonatum sibiricum primarily and identified by HPLC, UPLC-TOF-MS/MS and NMR analysis, respectively. Results showed that MPD repressed cell proliferation at IC50 of 18.49 µM, altered cell morphology, arrested the cell cycle in G2/M phase, facilitated the generation of intracellular ROS and led to cell apoptosis in a concentration-dependent manner. Furthermore, MPD treatment promoted death receptor pathway and mitochondrial pathway efficiently. The inhibition of Caspase-8 and Caspase-9 proteins in these pathways abolished the apoptosis significantly, further demonstrated the mechanism of MPD-induced apoptosis. These findings offer novel information that MPD may be considered as a possible natural anti-cancerous agent in the form of functional foods or medicinal products.

Mechanism of Juglone-Induced Cell Cycle Arrest and Apoptosis in Ishikawa Human Endometrial Cancer Cells.

The molecular mechanism of Juglone-induced cell cycle arrest and apoptosis in human endometrial cancer cells was investigated. Juglone was purified from the green husk of Carya cathayensis Sarg and identified by HPLC, LC-MS/MS, and NMR. At an IC50 of 20.81 µM, juglone significantly inhibited Ishikawa cell proliferation, as shown by S phase arrest mediated by inactivation of cyclin A protein ( p < 0.05). The ROS levels increased significantly after exposure to juglone, which paralleled increases in the mRNA and protein expression of p21 and decreases in the levels of CDK2, cdc25A, CHK1, and cyclin A. The expression of Bcl-2 and Bcl-xL was significantly down-regulated, whereas the expression of Bax, Bad and cyto c was up-regulated, and we later confirmed the involvement of the mitochondrial pathway in juglone-induced apoptosis. Our in vitro results stated that juglone can be studied further as an effective natural anticancer agent.

Licochalcone A from licorice root, an inhibitor of human hepatoma cell growth via induction of cell apoptosis and cell cycle arrest.

We investigated the anti-cancer activity of Licochalcone A (LCA), extracted from licorice root. LCA inhibited the proliferation of HepG2 cells with IC50 (65.96 µM) for 24 h and IC50 (44.13 µM) for 48 h and caused significant morphological changes and also led to intracellular ROS generation. LCA affected HepG2 cell growth by terminating cell cycle development at G2/M transition and further induced the apoptosis process. The mRNA expression of genes involved in cell cycles such as Survivin, Cyclin B1, and CDK1 were reduced; while, Weel, P21, Cyclin D1, and JNK1 showed increased mRNA expression. Two pathways consisting of internal and external factors were responsible for LCA -induced apoptosis. The anti-cancer action involved increased mRNA expression of DR3, DR5, caspases-3, caspases-8, caspases-10, Fas, Bad, Bax, Bcl-2, Bak, and PUMA; besides, decreased level of PKCε, p70S6K, and Akt. This study provides mechanistic explanation for anti-cancer activity of LCA and also suggests its potential role in the treatment of hepatoma cancer.

Molecular mechanism and inhibitory targets of dioscin in HepG2 cells.

Dioscin has been known for its anti-cancer activity; however, its detailed molecular mechanisms have not been studied so far. Herein, we evaluated the anti-cancer activity of dioscin for proliferation inhibition and apoptosis in HepG2 cancer cells. Initially, dioscin was purified and identified from Polygonatum sibiricum by HPLC, MS, and NMR analysis, respectively. Dioscin inhibited the cell multiplication at IC50 of 8.34 µM, altered the cell morphology, arrested the cell cycle in G2/M phase and led to considerable programmed cell death. Furthermore, it has efficiently promoted the mitochondrial pathway and death receptor pathway. The inhibition of Caspase-8 and Caspase-9 proteins in these pathways abolished the dioscin induced apoptosis significantly; while dioscin inhibited the PI3K/Akt/mTOR pathway. Moreover, dioscin exposure led to enhanced intracellular ROS generation and the mRNA expression of JNK gene which emphasized their involvement in the apoptosis process in HepG2 cells.

Effects of different chemical modifications on the antibacterial activities of polysaccharides sequentially extracted from peony seed dreg.

The peony seed dreg polysaccharide (PSDPs) fractions and their modified derivatives were examined for their antibacterial potential. PSDPs along with their derivatives exhibited appreciable antibacterial activity against both Gram-positive (B. subtilis and S. aureus) as well as Gram-negative (E. coli and S. typhimurium) bacteria. Among the four polysaccharide fractions, HBSS possessed the greatest antibacterial activity with an inhibition zone of 13.6 mm against S. typhimurium, minimal inhibitory concentration of 0.12% against S. typhimurium and maximum bacterial growth inhibition. For the modified derivatives, the sulfated modified fraction (S-HBSS) exhibited the maximum antibacterial activity with inhibition zone of 15.4 mm and minimal inhibitory concentration of 0.08% against S. typhimurium, followed by carboxymethylated and phosphorylated derivatives. Out of the four tested bacteria, S. typhimurium was observed as the most sensitive strain which was inhibited most effectively by all the polysaccharide fractions. Overall, our findings clearly indicated that the selected polysaccharide fractions can be used as food ingredients with potential natural antibacterial prospective.

Effects of different chemical modifications on the antioxidant activities of polysaccharides sequentially extracted from peony seed dreg.

Four types of sequentially extracted peony seed dreg polysaccharides (PSDPs) fractions were modified through sulfation, phosphorylation and carboxymethylation and studied for their in vitro antioxidant characteristics. The modified derivatives showed decreased sugar and protein content, while uronic acid content was elevated as compared to native (un-modified) polysaccharides. Further, modified derivatives shared the similar maximum absorption peaks indicating their homogeneous nature. The Fourier transform infrared (FTIR) spectra of sulfated, carboxymethylated and phosphorylated derivatives showed that hydroxyl groups were converted to OS, COO and POH bonds, respectively. The sulfated polysaccharides (S-PSDPs) displayed the highest reducing ability [S-CASS (1.854)], DPPH radical scavenging ability [S-CASS (95.07%)] and ABTS radical scavenging activity [S-CASS (99.85%)]. The phosphorylated polysaccharides (P-PSDPs) exhibited maximum hydroxyl radical scavenging activity [P-DASS (92.61%)] and ferrous ion chelating ability (99.94% for all the fractions). The carboxymethylated polysaccharides (C-PSDPs) maintained moderately stable antioxidant ability. Overall, the four different PSDPs modified by the same chemical method also resulted into different chemical composition, characteristic absorption peaks and antioxidant attributes. We conclude that the different modifications of the polysaccharide fractions had their own potential significance as new antioxidants for food industry and human health.

Simultaneous and fast separation of three chlorogenic acids and two flavonoids from bamboo leaves extracts using zirconia.

Phenolic acids and flavonoids in bamboo leaves are of great importance for their functional attributes, but they can hardly be separated simultaneously. In this study, zirconia was prepared and applied as a potential absorbent for simultaneous separation of these phenolic compounds. Three phenolic acids (neochlorogenic acid, chlorogenic acid and cryptochlorogenic acid) and two flavonoids (isoorientin and orientin) were isolated at the same time. The influence of bamboo leaves extraction conditions, zirconia calcination temperatures, desorption conditions and absorption/desorption dynamics on the separation were further investigated. When zirconia-400 (calcined at 400 °C) was treated with 70% ethanol extract of bamboo leaves for 40 min followed by desorption with 70% acetic acid solution for 60 min, the recovery of three chlorogenic acids and two flavonoids was about 65%. To conclude, the concise method developed here may provide a new way for simultaneous separation of phenolic acids and flavonoids from various plants.