Weiqing Cheng

The rhizome of Polygonatum sibiricum is a traditional Chinese medicine material and also a popular functional food consumed in China. Due to the increasing demand and overexploitation, the use of the cultivated plant is growing rapidly. However, the difference in phytochemical profile and health benefit between the cultivated and wild-grown P. sibiricum has not been revealed yet. The objectives of this study are to compare the phytochemical profiles of two types of P. sibiricum, i.e., the cultivated and the wild-grown types, by using UHPLC-Q-Orbitrap-MS based untargeted metabolomics approach. We tentatively identified 190 phytochemicals belonging to alkaloids, flavonoids, phenolic acids, and terpenoids from both two types of samples. In general, there is distinctive difference in phytochemical profiles between these two types of samples. Specifically, 33 phytochemicals showed significant differences. Of these phytochemicals, 22 compounds, such as laetanine, p-coumaroyl-beta-D-glucose, geniposide, medicagenic acid, were significantly higher in cultivated type; 11 compounds, such as vicenin-2, kaempferol 7-neohesperidoside, vanillic acid, and obacunone, were significantly higher in wild-grown type samples. This study will expand our knowledge regarding the cultivated of P. sibiricum and facilitate its further application in pharmaceutical and food industries.

The rhizomes of Polygonatum sibiricum are commonly consumed as food and also used as medicine. However, the metabolic profile of P. sibiricum has not been fully revealed yet. Recently, we developed a novel evergreen species of P. sibiricum. The objectives of this study were to compare the metabolic profiles of two types of P. sibiricum, i.e., the newly developed evergreen type (Gtype) and a wide-type (Wtype), by using UHPLC-Q-Orbitrap-MS-based untargeted metabolomics approach. A total of 263 and 258 compounds in the positive and negative modes of the mass spectra were tentatively identified. Distinctively different metabolomic profiles of these two types of P. sibiricum were also revealed by principal component analysis (PCA) and principal coordinates analysis (PCoA). Furthermore, by using partial least squares discriminant analysis (PLS-DA) modeling, it was found that, as compared with Wtype, Gtype samples had significantly higher content of oxyberberine, proliferin, alpinetin, and grandisin. On the other hand, 15 compounds, including herniarin, kaempferol 7-neohesperidoside, benzyl beta-primeveroside, vanillic acid, biochanin A, neoschaftoside, benzyl gentiobioside, cornuside, hydroxytyrosol-glucuronide, apigenin-pentosyl-glucoside, obacunone, 13-alpha-(21)-epoxyeurycomanone, vulgarin, digitonin, and 3-formylindole, were discovered to have higher abundance in Wtype samples. These distinguishing metabolites suggest the different beneficial health potentials and flavor attributes of the two types of P. sibiricum rhizomes.

CdS nanoparticles capped by mercaptoacetic acid have been successfully synthesized by microwave method employing thioacetamide as sulfur source, which was proved to be a simple, rapid and specific mothod compared with traditional synthetical methods, such as precipitation, sol-gel, solvo-thermal method and so on. The concrete procedure synthesizing CdS nanoparticles was as follows: Cd(NO3)2 (40 mL, 5 mmol c L(-1)) was titrated with mercaptoacetic acid to pH 2.0, resulting in a turbid blue solution. NaOH (0.1 mol x L(-1)) was then added dropwise until the pH was 7 and the solution was again colorless. While quickly stirring the solution, 40 mL of 5 mmol x L(-1) CH3CSNH2 was added. Subsequently, the solution was adjusted to pH 9.0 and placed in a microwave oven for 25 min with power 30% (it means that if microwave works in a 30 s regime, it works 6 s, and does not work 24 s. This is some kind of pulse regime, but the totalpower is still 100%). This kind of nanoparticles were water-soluble and symmetrical. The diameter of CdS nanoparticles which have a spherical morphology was determined to be 12 nm by transmission electron microscopy(TEM), which posess perfect uniforminty. According to literatures report, there are two kinds of emission peak: one is edge-emission peak, and the other is surface blemish emission. In contrast to edge-emission peak, the surface blemish emission shows red shift on fluorescence spectra. In the present paper, the prominent peak of CdS QDs fluorescence spectrum was located at 490 nm, the humpbacked peak caused by surface blemish of CdS nanoparticles was located at 565 nm. However, the surface blemish emission was unconspicuous, thus we can conclude that the synthetical CdS QDs possesses excellent luminescence capability and favorable structure. The size and absorption and fluorescence spectra of CdS nanoparticles at different microwave power, pH value, reaction time and different sulfur source were investigated. The result showed that the better nanoparticles could be obtained in the condition of 30% microwave power, pH 9.0 at the beginning of reaction, and the time of microwave reaction of 25 min. The synthesized nanoparticles were compared with the nanoparticles with CH3 CSNH2, NH2CSNH2 and Na2S as sulfur source. The experiment indicated that CdS nanoparticles applying CH3CSNH2 as sulfur source showed strong edge-emission, and blemish emission was weak, so the fluorescence quality is excellent; but CdS nanoparticles applying NH2CSNH2 as sulfur source showed weak edge-emission; and CdS nanoparticles applying Na2S as sulfur source showed mainly fluorescence blemish emission. At the same time, the mercaptoacetic acid capped CdS nanoparticles were employed to study the quantitative analysis of Cu2+. According to the results of experiment, in a certain range of concentration(6.4-512 microg x L(-1)), Cu2+ quenched the fluorescence intensity of mercaptoacetic acid capped CdS nanoparticles with good linearity, which can be used in the determination of trace Cu2+ in samples. In conclusion, this kind of method supplied a new way to study synthesizing the CdS nanoparticles.