Direct Biotransformation of Dioscin into Diosgenin in Rhizome of Dioscorea zingiberensis by Penicillium dioscin.

Diosgenin is an important precursor for synthesis of more than 200 steroidal hormone medicines. Rhizome of Dioscorea zingiberensis C. H. Wright (RDZ) contained the highest content of diosgenin in Dioscorea plant species. Diosgenin is traditionally extracted by acid hydrolysis from RDZ. However, the acid hydrolysis process produces massive wastewater which caused serious environment pollution. In this study, diosgenin extraction by direct biotransformation with Penicillium dioscin was investigated. The spawn cultivation conditions were optimized as: Czapeks liquid culture medium without sugar and agar (1,000 ml) + 6.0 g dioscin/6.0 g DL, 30 °C, 36 h; solid fermentation of RDZ: mycelia/RDZ of 0.05 g/kg, 30 °C, 50 h; the yield of diosgenin was over 90 %. Spawn cultivation was crucial for the direct biotransformation. In the spawn cultivation, amount and ratio of dioscin/DL were the key factors to promote biotransformation activity of P. dioscin. This biotransformation method was environment-friendly, simple and energy saving, and might be a potential substitute for acid hydrolysis in diosgenin extraction industry.

Identifying three ecological chemotypes of Xanthium strumarium glandular trichomes using a combined NMR and LC-MS method.

Xanthanolides, as the sesquiterpene lactones, are reportedly the major components for the pharmacological properties of X. strumarium L. species. Phytochemical studies indicated that the glandular structures on the surface of plant tissues would form the primary sites for the accumulation of this class of the compounds. As the interface between plants and their natural enemies, glandular trichomes may vary with respect to which of their chemicals are sequestered against different herbivores in different ecologies. However, to date, no data are available on the chemical characterisation of X. strumarium glandular cells. In this study, the trichome secretions of the X. strumarium species originating from nineteen unique areas across eleven provinces in China, were analysed by HPLC, LC-ESI-MS and NMR. For the first time three distinct chemotypes of X. strumarium glandular trichomes were discovered along with the qualitative and quantitative evaluations of their presence of xanthanolides; these were designated glandular cell Types I, II, and III, respectively. The main xanthanolides in Type I cells were 8-epi-xanthatin and xanthumin while no xanthatin was detected. Xanthatin, 8-epi-xanthatin, and xanthumin dominated in Type II cells with comparable levels of each being present. For Type III cells, significantly higher concentrations of 8-epi-xanthatin or xanthinosin (relative to xanthatin) were detected with xanthinosin only being observed in this type. Further research will focus on understanding the ecological and molecular mechanism causing these chemotype differences in X. strumarium glandular structures.

Variation of epimedins A - C and icariin in ten representative populations of Epimedium brevicornu Maxim., and implications for utilization.

The concentration variations of main flavonoids, epimedins A-C and icariin, among ten representative populations of Epimedium brevicornu Maxim. were assessed by HPLC. The populations were collected during the flowering stage and included 419 individual samples. Remarkable variations within and among populations were detected. SXXA Population (see Fig. 1) was an outlier due to its significant low concentrations (<1.00-4.46 mg/g). But even without SXXA, significant concentration differences among populations were still observed in epimedin A (2.31-8.42 mg/g), epimedin B (6.67-55.7 mg/g), epimedin C (5.39-23.0 mg/g), icariin (8.50-39.9 mg/g), and their total (29.1-123 mg/g). All populations except SXXA showed much higher concentrations than the recommended standards (i.e. 5 mg/g for icariin and 13 mg/g for the total). A high-concentration-population structure, estimated both by principal component analysis (PCA) and unweighted pair group method with averaging (UPGMA) cluster analysis, based on Euclidean distances, was observed. Both methods allowed separation of the populations in four groups defined by the concentrations of four main flavonoids. The populations (SXLC and SXQS) located in north of Yellow River were clustered together and characterized by highest concentrations of epimedin B, icariin, and their total. Considering of the high concentrations of main flavonoids and abundant resources, E. brevicornu could be exploited as a good medical resource for Herba Epimedii and would offer a tremendous potential for commercial development, but SXXA population should be paid special attention, and further study is needed.

Comparison of major phenolic constituents and in vitro antioxidant activity of diverse Kudingcha genotypes from Ilex kudingcha, Ilex cornuta, and Ligustrum robustum.

A total of seven Kudingcha genotypes from three plant species (Ilex kudingcha, Ilex cornuta, and Ligustrum robustum) with different geographic origins in China were investigated for their major phenolic compounds, individual and total phenolics contents, and in vitro antioxidant properties (ABTS, DPPH, FRAP, and OH assays). LC-PDA-APCI-MS analysis showed that Kudingcha genotypes from Ilex and Ligustrum had entirely different phenolic profiles. Major phenolics in Kudingcha genotypes from two Ilex species were mono- and dicaffeoylquinic acids, whereas those in a Kudingcha genotype from Ligustrum were phenylethanoid and monoterpenoid glycosides. All Kudingcha genotypes of Ilex exhibited significantly stronger antioxidant capacities than that of Ligustrum. Within six Ilex genotypes, great variation existed in their composition of individual phenolic compounds and their antioxidant properties. The comparative data and LC fingerprints obtained in this study may provide useful information for screening and breeding of better Kudingcha genotypes and also for their authentication and quality control.

Pristimerin induces apoptosis by targeting the proteasome in prostate cancer cells.

Pristimerin is a natural product derived from the Celastraceae and Hippocrateaceae families that were used as folk medicines for anti inflammation in ancient times. Although it has been shown that pristimerin induces apoptosis in breast cancer cells, the involved mechanism of action is unknown. The purpose of the current study is to investigate the primary target of pristimerin in human cancer cells, using prostate cancer cells as a working model. Nucleophilic susceptibility and in silico docking studies show that C6 of pristimerin is highly susceptible towards a nucleophilic attack by the hydroxyl group of N-terminal threonine of the proteasomal chymotrypsin subunit. Consistently, pristimerin potently inhibits the chymotrypsin-like activity of a purified rabbit 20S proteasome (IC50 2.2 micromol/L) and human prostate cancer 26S proteasome (IC50 3.0 micromol/L). The accumulation of ubiquitinated proteins and three proteasome target proteins, Bax, p27 and I kappa B-alpha, in androgen receptor (AR)-negative PC-3 prostate cancer cells supports the conclusion that proteasome inhibition by pristimerin is physiologically functional. This observed proteasome inhibition subsequently led to the induction of apoptotic cell death in a dose- and kinetic-dependent manner. Furthermore, in AR-positive, androgen-dependent LNCaP and AR-positive, androgen-independent C4-2B prostate cancer cells, proteasome inhibition by pristimerin results in suppression of AR protein prior to apoptosis. Our data demonstrate, for the first time, that the proteasome is a primary target of pristimerin in prostate cancer cells and inhibition of the proteasomal chymotrypsin-like activity by pristimerin is responsible for its cancer cell death-inducing property.

Characterization of astaxanthin esters in Haematococcus pluvialis by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry.

After first being analyzed by HPLC, 4 free carotenoids, 15 astaxanthin monoesters, 12 astaxanthin diesters, and 3 astacin monoesters in Haematococcus pluvialis were identified by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry (LC-(APCI)MS). Identification of each compound was based on the characteristic fragment ions of the positive ion mode, negative ion mode, and MS(2). Astaxanthin esters were identified based on the loss of one or two fatty acids. In a positive ion mode, astaxanthin monoesters had characteristic fragment ions at m/z 597 [M+H-fatty acid](+) and m/z 579 and 561 that resulted from a continuous loss of water. The relative intensity of m/z 579 in MS(2) amounted to more than 80% of that of the molecular ion. In astaxanthin diesters, the intensity of m/z 561 occasionally was equal to that of m/z 579, but in general the former, amounting to 50 to 60% or more of the molecular ion, was stronger than the latter, which decreased to 20 to 30% of the molecular ion. In addition, a set of compounds with maximum absorbance at 400 nm, detected by high-performance liquid chromatography-diode array detector (HPLC-DAD), had strong characteristic fragment ions at m/z 871 and 593 in the positive ion mode MS(2). They were presumed to be linolenic acid or an isomer of omega-6-gamma-linolenic acid esters of astacin.