Separation and enrichment of sibiskoside from Sibiraea angustat with magnetic surface dummy template molecularly imprinted polymers

In this work, a novel strategy was developed for separation and enrichment of sibiskoside by dummy molecular imprinting technology and magnetic separation technology. The structural analogue geniposide was selected as the dummy template, using 4-vinylpyridine as the functional monomer, ethylene glycol dimethacrylate as the cross-linking agent, and acetonitrile as the porogen. The molecularly imprinted layer was formed on the surface of the magnetic carrier to prepare dummy template molecularly imprinted polymers (DMIPs) with a core-shell structure. The DMIPs were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and Vibration sample magnetometer (VSM). The results of adsorption kinetics experiments and isothermal adsorption experiments showed that DMIPs can reach adsorption equilibrium in a short period of time and the maximum adsorption capacity can reach 14.67 mg/g. The imprinting factor was 2.08. Compared with the andrographolide, polydatin, arbutin, caffeic acid, neohesperidin dihydrochalcone and quercetin, DMIPs have good adsorption capacity for the sibiskoside. And the reusability was better. After the adsorption of DMIPs, the purity of sibiskoside in the crude extracts from Sibiraea angustata increased to 78%. It provided a basis for the further development and utilization of Sibiraea angustata as well as the separation and enrichment of monoterpenes.

Hypolipidemic constituents from the aerial portion of Sibiraea angustata

Two new monoterpene acylglucosides (1-2) and one new aromatic glycoside (3), together with five known compounds (4-8), were isolated from 95% ethanol extract of Sibiraea angustata. The structures of these compounds were characterized by 2D-NMR and mass spectrometry. Compounds were evaluated for their hypolipidemic activity using oleic acid-induced lipid accumulation in HepG2 cells. RT-PCR analysis revealed that compound 5 could decrease the expression level of fatty acid synthase (FASN). Lipidomics analysis indicated that compound 5 significantly decreased the levels of 11 lipids in oleic acid-induced lipid accumulation, including triglycerides (TG), diglycerides (DG), phosphatidylcholines (PC) and 1-acyl-sn-glycero-3-phosphocholines (lysoPC). These data demonstrated that terpene acylglucosides are the major active constituents in Sibiraea angustata.

Amido surface-functionalized magnetic molecularly imprinted polymers for the efficient extraction of Sibiskoside from Sibiraea angustata

A general method for efficient and selective extraction of a target compound from complex natural products remains elusive, despite decades of research. By introducing a functional amido group on the surface of dispersity-enhanced magnetic nanoparticles, a nanoparticle receptor to selectively recognize Sibiskoside (a monoterpene) from the aerial portion of Sibiraea angustata by hydrogen bond interaction was synthesized. The superparamagnetic Fe₃O₄ nanoparticles were successively modified with tetraethyl orthosilicate (TEOS), amino and amido functional groups, and 4-vinylbenzoic acid (VBZA) was used as the functional monomer. A thin layer of poly (VBZA) imprinted with Sibiskoside was immobilized on the surface of magnetic carriers. Attributing to the amido group introduced into the magnetic particles, the template could attract and bind to the surface and promote the formation of a hydrogen bond system between the carrier, template molecules and functional monomer. High-density molecular recognition sites grew on the surface of magnetic substrate. The adsorption reached equilibrium at approximately 150 min, while fast adsorption occurred during the first 60 min. The maximum adsorption capacity has been found to be 13.75 mg g^-1 according to calculation with the Langmuir isotherm. The selectivity coefficients of Molecular imprinting polypers (MIPs) for Sibiskoside with respect to Andrographolide, Loganin, Gastrodin, geraniol-1-O-[α-l-rhamnopyranosyl-(1 → 6)-1-β-d-glucopyranoside] (GRG), Sibiscolacton and Sibiraic acid were 2.26, 1.43, 1.701.56, 1.05, 0.73 and, respectively. The results indicated that the MIPs possessed good specific adsorption capacity and selectivity toward Sibiskoside and had the potential to be a candidate for the separation and purification of monoterpenes from Sibiraea angustata, which is of great significance to obesity management.

Two new monoterpenes from Sibiraea laevigata

Two new monoterpenes, 3-(2-oxo-4-methyl-3-pentenyl)furan-5H-2-one (1) and 3-[(2E)-4-hydroxyl-4-methyl-2-pentenyl)]furan-5H-2-one (2), along with eight known compounds (3-10), were isolated from the stalks and infructescence of Sibiraea laevigata. Their structures were elucidated by spectroscopic methods including extensive 1D and 2D NMR techniques. In addition, all of these isolates were evaluated for their cytotoxic and antioxidant activities. The results showed that compounds 5-7 displayed cytotoxicity with IC₅₀ values ranging from 34.8 to 43.2 μg ml^-1 against tumor cell lines. Furthermore, 5 and 9 showed antioxidant activities.

Monoterpenoids from the traditional North Italian vegetable Aruncus dioicus (Walter) Fernald var. vulgaris (Maxim.) H.Hara (Rosaceae)

Investigations of young shoots of Aruncus dioicus (Walter) Fernald var. vulgaris (Maxim.) H.Hara (Rosaceae), collected from the wild and used as vegetables in alpine provinces of Italy, yielded eight monoterpenoids. Besides known compounds, aruncin A, aruncide A, and cimicifugolide, five previously undescribed substances, aruncins C, D, and E, and aruncides D and E, were identified. Based on results from the full synthesis of aruncin B, structures of aruncin A and aruncide A were revised. Structures were established by HR mass spectrometry and extensive 1D and 2D NMR spectroscopy and based on data from synthetic aruncin B. An HPLC-DAD-ESI-MS method was developed to investigate the distribution of the monoterpenoids in different organs of Aruncus dioicus var. vulgaris and in aerial parts of A. dioicus var. aethusifolius (H.Lév.) H.Hara [Syn.: Aruncus aethusifolius (H.Lév.) Nakai]. Preliminary bioactivity studies moreover indicated weak cytotoxicity for some of the compounds against human prostrate adenocarcinoma cells.

Antioxidants and α-glucosidase inhibitors from "Liucha" (young leaves and shoots of Sibiraea laevigata)

The young leaves and shoots of Sibiraea laevigata, known as "Liucha", are used as tea by Tibetans to improve digestion after meals. Long-term consumption of "Liucha" will cause weight loss. In present work, we reported on the isolation and NMR and chemical analysis-based elucidation of seven new sorbitol O-caffeic acid ester derivatives named sorbitol esters A-G (1-7) and eighteen known phenolic compounds from S. laevigata. All of the isolates were evaluated for their antioxidant and α-glucosidase inhibitory activities. Among them sorbitol ester A (1), sorbitol ester D (4), sorbitol ester F (6), sorbitol ester G (7), isoferulic acid (15), methyl caffeate (18), trans-p-hydroxycinnamic acid (19), and kaempferol 3-O-β-d-(6″-E-p-coumaroyl)-glucopyranoside (25) showed more potent α-glucosidase inhibitory activity than the clinical drug acarbose.

Three new monoterpene glucosides from Sibiraea angustata

Three new monoterpene glycosides, named sibiraglycoside I(1), J(2) and K(3), were isolated from an aqueous extract of the aerial portion of Sibiraea angustata. Their structures were elucidated on the basis of extensive spectroscopic data analysis (including 1D and 2D NMR and MS experiments) and compared to literature data.

Eight New Monoterpene Acylglucosides from Sibiraea angustata

Chemical investigation of the aqueous extract from the aerial part of Sibiraea angustata, has led to the isolation of eight new monoterpene acylglucosides named sibiraglycoside A-H(1-8), together with two known monoterpenes, Sibiraic acid (9) and Sibiskoside (10). Their structures were elucidated by means of extensive spectroscopic data analysis (including 1D and 2D NMR, HRESIMS experiments), as well as compared with the literature data. The relative configuration was established by NOE studies. In the in vitro bioassay, all the compounds showed moderate hypolipemic effects, among them, compounds 7 and 9, showed distinctive activity on lowering lipid.

Highly oxygenated monoterpene acylglucosides from Spiraea cantoniensis

Six new monoterpene acylglucosides named kodemariosides A-F (1-6) were isolated from the leaves and flowers of Spiraea cantoniensis. Their absolute structures including a highly oxygenated monoterpene aglycon part were determined by NMR experiments and chemical derivatization.