Pyrrolizidine alkaloids from Jacobaea vulgaris Gaertn and theoretical studies on intramolecular interactions.

Two undescribed pyrrolizidine alkaloids, 13-dehydrosenkirkine (1) and chloromethylretrorsine (2), along with three known analogues, onetine (3), retrorsine (4), and usaramine N-oxide (5), were isolated from Jacobaea vulgaris Gaertn. The structures of the undescribed compounds were elucidated by extensive spectrometric and spectroscopic techniques, including HRESIMS, NMR, calculated 13C-NMR DP4+ analysis and comparison with experimental and calculated ECD spectra. The undescribed compounds were evaluated for their antitumour activity against HT29, HeLa, and HepG2 cells. In addition, the intramolecular interactions and quadrupolar couplings were revealed by investigating the geometrical and electronic properties of three typical otonecine-type PAs in DFT theory.

Anti-Melanogenesis Effect of Polysaccharide from Saussurea involucrata on Forskolin-Induced Melanogenesis in B16F10 Melanoma Cells.

As one of the prominent medicinal plants listed in the Chinese pharmacopoeia (2020), Saussurea involucrata (Kar. et Kir.) Sch.-Bip was demonstrated to possess various therapeutic effects. In our recent research, we extracted the polysaccharides from S. involucrata (SIP) at optimal conditions and conducted further structure elucidation on the main fraction as well as the confirmation of its possible anti-inflammatory activity. Hence, in this work, we assessed the in vitro antioxidant activity and anti-melanogenesis effects of the crude SIP in forskolin-induced B16F10 melanoma cells. The results show that SIP possessed strong antioxidant activity and was effective in concentration-dependently decreasing melanin formation and inhibiting tyrosinase activity in forskolin-induced B16F10 cells. Based on these results, the inhibitory mechanism of melanogenesis was investigated by measuring Tyrosinase (TYR), Tyrosinase related protein-1 (TRP-1), Tyrosinase related protein-2 (TRP-2), Microphthalmia-associated transcription factor (MITF), cAMP-response element binding protein (CREB), mitogen-activated protein kinases (MAPK) signaling protein members, and ß-catenin degradation in forskolin-induced B16F10 cells. The anti-melanogenesis response of SIP might be attributed to the regulation of c-Jun N-terminal kinase (JNK) phosphorylation and ß-catenin degradation pathways. These results suggest that polysaccharides from S. involucrata possess a strong anti-melanogenic effect, and thus could be used as a high-value natural material for skin whitening in cosmeceutical industries.

Isolation, structure elucidation, and biological activity of polysaccharides from Saussurea involucrata.

The optimum extraction condition for the Saussurea involucrata polysaccharide (SIP) was determined to be a temperature of 80 °C, time 2 h, and a liquid-solid ratio of 30 mL/g with a yield of 11.37 %. An acidic homogenous polysaccharide, namely SIP-II was isolated from Saussurea involucrate through anion exchange and gel permeation column chromatography. The structure of the SIP-II was elucidated through the combination of HPLC, GC-MS, IC, peroxide oxidation, smith degradation, methylation, NMR analysis, it was mainly composed of arabinose, rhamnose, galactose, galacturonic acid, and glucose with the molar ratio of 19.85:20.30: 27.12:11.95:8.69 with a molecular weight of 237,570 Da. The glycosidic linkages of SIP-II mainly composed of →1)-α-L-Rhap-(2→, T-Araf, →1)-ß-D-GalpA-(4→, →1)-ß-D-Galp-(3,6→, →1)-ß-D-Galp-(6→, →1)-α-L-Rhap-(2,4→, T-Galp, and →1)-α-L-Araf-(5→. Meanwhile, the structures were characterized through extensive analysis of UV, FT-IR, SEM-EDX, CD, XRD, and TG. SIP-II possessed a remarkable anti-inflammatory activity by effectively inhibiting the expression of pro-inflammatory cytokines and inflammation-related mediators in LPS-stimulated RAW264.7 macrophages, and the anti-inflammatory response of SIP-II might be attributed to the regulation of the NF-κB, MAPK and JAK/STAT pathways. The results showed that polysaccharides from Saussurea involucrate could be a potential ingredient in the functional food and pharmaceutical industry.

Identification and quantification of Meiguihua oral solution using liquid chromatography combined with hybrid quadrupole-orbitrap and triple quadrupole mass spectrometers.

Meiguihua oral solution (MOS), a classical Chinese medicinal formula, was approved by the China Food and Drug Administration for production. However, the quality evaluation of MOS has not been reported. In this present study, qualitative and quantitative analysis of MOS were conducted by ultra high performance liquid chromatography coupled to quadrupole-orbitrap high resolution mass spectrometry (UHPLC-Q-orbitrap-HRMS) and high performance liquid chromatography-tri-quadrupole linear ion trap mass spectrometry (HPLC-tri-Q-LIT-MS). Totally 46 phenolic compounds (21 flavonoids and 25 tannins) were identified in the MOS, among them 14 polyphenols were not reported in raw plant materials of MOS. The simultaneous quantification of ten compounds including gallic acid, quercetin-3-O-sophoroside, ellagic acid, sophoraflavonoloside, hyperoside, isoquercitrin, avicularin, astragalin, quercitrin and juglanin, which were completed in 16 min in the negative electrospray ionization (ESI) mode under multiple reaction monitoring (MRM) method. Linearity was reached fine determination coefficient (r2 > 0.9995). Precisions, repeatability, stability (inter-day and intra-day), and recovery were validated and the relative standard deviations (RSD) were less than 2.9%, 4.7%, 3.6% and 1.79%, respectively. This result proved the high sensitivity and efficiency of the method. The quantitative and qualitative analysis of MOS would provide the substantial basis for further quality control and medicinal values.

Jatrophane Diterpenoids from Euphorbia glomerulans.

In a phytochemical investigation of the whole plant of Euphorbia glomerulans, 17 new (1-17) and five known jatrophane diterpenoids (18-22) were identified. The X-ray crystallographic data of compounds 1, 4, and 21 permitted the definition of the absolute configurations of these compounds. The cytotoxicity and multidrug resistance reversal activities of the 17 new compounds were evaluated on multidrug-resistant MCF-7/ADR cells overexpressing P-glycoprotein. Several compounds showed different chemoreversal activities and considerably decreased cytotoxicity. Compounds 11 (IC50 value of 5.0 ± 0.8 µM) and 12 (IC50 value of 5.2 ± 2.0 µM) possessed MDR reversal activities that were as good as that of verapamil (IC50 value of 4.7 ± 0.6 µM).

Manganese-mitigation of cadmium toxicity to seedling growth of Phytolacca acinosa Roxb. is controlled by the manganese/cadmium molar ratio under hydroponic conditions.

Manganese (Mn) can interact with cadmium (Cd) in environments and influence the toxic effect of Cd on plants. However, few studies have investigated the relationship between the Mn/Cd ratio and plant Cd-toxicity along Cd concentrations. In this paper, we studied the effects of external Mn/Cd molar ratios (0, 10, 30, 50 and 60) on Cd toxicity in the Mn hyperaccumulator and Cd tolerant plant, Phytolacca acinosa Roxb., at three Cd levels (50, 100 and 200 µM) under hydroponic conditions. Our result showed that seedling growth (y) under Cd stress was strongly positively related to the solution Mn/Cd molar ratio (SMCR). The relationship between the two variables under solution Cd concentrations was well explained by the linear regression model y=a+b1 (SMCR)+b2 (Solution-Cd). Increasing SMCR significantly reduced the Cd concentration and increased the Mn concentration in plant tissues. However, seedling growth was consistent with the shoot Mn/Cd molar ratio rather than with the Mn or Cd concentrations in plant tissues. At low levels of SMCR (e.g. 0 and 10), elevation of Mn distribution in shoot tissues might be a mechanism in P. acinosa seedlings to defend against Cd-toxicity. In comparison with low levels of SMCR, high levels of SMCR (e.g. 50 and 60) greatly alleviated lipid peroxidation and plant water-loss, and enhanced photosynthesis. However, the alleviated lipid peroxidation in the Mn-mitigation of Cd toxicity was likely to be the secondary effect resulting from the antagonism between Mn and Cd in the plant.

Phytochelatin synthase of Thlaspi caerulescens enhanced tolerance and accumulation of heavy metals when expressed in yeast and tobacco.

Phytochelatin synthase (PCS) is key enzyme for heavy metal detoxification and accumulation in plant. In this study, we isolated the PCS gene TcPCS1 from the hyperaccumulator Thlaspi caerulescens. Overexpression of TcPCS1 enhanced PC production in tobacco. Cd accumulation in the roots and shoots of TcPCS1 transgenic seedlings was increased compared to the wild type (WT), while Cd translocation from roots to shoots was not affected under Cd treatment. The root length of the TcPCS1 transgenic tobacco seedlings was significantly longer than that of the WT under Cd stress. These data indicate that TcPCS1 expression might increase Cd accumulation and tolerance in transgenic tobacco. In addition, the malondialdehyde content in TcPCS1 plants was below that of the wild type. However, the antioxidant enzyme activities of superoxide dismutase, peroxidase and catalase were found to be significantly higher than those of the WT when the transgenic plant was exposed to Cd stress. This suggests that the increase in PC production might enhance the Cd accumulation and thus increase the oxidative stress induced by the cadmium. The production of PCs could cause a transient decrease in the cytosolic glutathione (GSH) pool, and Cd and lower GSH concentration caused an increase in the oxidative response. We also determined TcPCS1 in Thlaspi caerulescens was regulated after exposure to various concentrations of CdCl(2) over different treatment times. Expression of TcPCS1 leading to increased Cd accumulation and enhanced metal tolerance, but the Cd contents were restrained by adding zinc in Saccharomyces cerevisiae transformants.