LeuRS can leucylate type I and type II tRNALeus in Streptomyces coelicolor.

Transfer RNAs (tRNAs) are divided into two types, type I with a short variable loop and type II with a long variable loop. Aminoacylation of type I or type II tRNALeu is catalyzed by their cognate leucyl-tRNA synthetases (LeuRSs). However, in Streptomyces coelicolor, there are two types of tRNALeu and only one LeuRS (ScoLeuRS). We found that the enzyme could leucylate both types of ScotRNALeu, and had a higher catalytic efficiency for type II ScotRNALeu(UAA) than for type I ScotRNALeu(CAA). The results from tRNA and enzyme mutagenesis showed that ScoLeuRS did not interact with the canonical discriminator A73. The number of nucleotides, rather than the type of base of the variable loop in the two types of ScotRNALeus, was determined as important for aminoacylation. In vitro and in vivo assays showed that the tertiary structure formed by the D-loop and TψC-loop is more important for ScotRNALeu(UAA). We showed that the leucine-specific domain (LSD) of ScoLeuRS could help LeuRS, which originally only leucylates type II tRNALeu, to aminoacylate type I ScotRNALeu(CAA) and identified the crucial amino acid residues at the C-terminus of the LSD to recognize type I ScotRNALeu(CAA). Overall, our findings identified a rare recognition mechanism of LeuRS to tRNALeu.

Siamese crocodile bile induces apoptosis in NCI-H1299 human non-small cell lung cancer cells via a mitochondria-mediated intrinsic pathway and inhibits tumorigenesis.

Non-small-cell lung cancer (NSCLC) is a widespread and particularly aggressive form of cancer. Patients with NSCLC and early metastases typically have poor prognosis, highlighting the critical need for additional drugs to improve disease outcome following surgical resection. The present study aimed to determine if Siamese crocodile bile (SCB) had an anti­cancer effect on NCI­H1299 human NSCLC cells. The inhibitory mechanism of SCB was examined in cell culture and nude mice. In vitro experimental results revealed that SCB inhibited the proliferation and colony­forming ability of NCI­H1299 cells by arresting cell cycle and inducing apoptosis. The loss of the mitochondrial membrane potential and the release of cytochrome c indicated that SCB treatment may lead to mitochondrial dysfunction in NCI­H1299 cells. At the molecular level, SCB altered the ratio of protein expression of Bax/Bcl­2 and activated associated caspases, suggesting that intrinsic pathway involvement in the SCB­induced apoptosis of NCI­H1299 cells. In the in vivo experiments, intraperitoneal injection of SCB for 4 weeks inhibited xenograft tumor growth by 46.8% without observable toxicity in nude mice. Immunohistochemistry analysis of proliferating cell nuclear antigen and vascular endothelial growth factor also revealed that SCB inhibited cell proliferation and metastasis in NSCLC xenograft tumors. Overall, SCB exerted an anti-cancer effect on NCI­H1299 human NSCLC cells in vitro and in vivo and may have therapeutic potential for the treatment of human NSCLC.

HSCCC-based strategy for preparative separation of in vivo metabolites after administration of an herbal medicine: Saussurea laniceps, a case study.

This paper reports a novel strategy based on high-speed counter-current chromatography (HSCCC) technique to separate in vivo metabolites from refined extract of urine after administration of an herbal medicine. Saussurea laniceps (SL) was chosen as a model herbal medicine to be used to test the feasibility of our proposed strategy. This strategy succeeded in the case of separating four in vivo metabolites of SL from the urine of rats. Briefly, after oral administration of SL extract to three rats for ten days (2.0 g/kg/d), 269.1 mg of umbelliferone glucuronide (M1, purity, 92.5%), 432.5 mg of scopoletin glucuronide (M2, purity, 93.2%), 221.4 mg of scopoletin glucuronide (M3, purity, 92.9%) and 319.0 mg of scopoletin glucuronide (M4, purity, 90.4%) were separated from 420 mL of the rat urine by HSCCC using a two-phase solvent system composed of methyl tert-butyl ether-n-butanol-acetonitrile-water (MTBE-n-BuOH-ACN-H2O) at a volume ratio of 10:30:11:49. The chemical structures of the four metabolites, M1 to M4, were confirmed by MS and (1)H, (13)C NMR. As far as we know, this is the first report of the successful separation of in vivo metabolites by HSCCC after administration of an herbal medicine.

The growth and medicinal quality of Epimedium wushanense are improved by an isolate of dark septate fungus.

CONTEXT: Seven dark-septate endophytic (DSE) fungi have been isolated from the roots of Epimedium wushanense T. S. Ying (Berberidaceae), an important medicinal plant with various pharmacological activities. OBJECTIVE: The current study explores the effects of seven DSE fungi on the growth and accumulation of bioactive compounds in E. wushanense. MATERIALS AND METHODS: Each 1-month-old E. wushanense seedling was inoculated with one of the seven DSE fungi and was grown under greenhouse conditions for 90 d. The molecular identification of the fungi was based on the ITS1-5.8S-ITS2 nuclear ribosomal gene cluster. RESULTS: The results showed that the influence of DSE fungi inoculation varied between strains. Inoculation with DSE8 not only significantly enhanced plant height, root length, leaf area, leaf number, and shoot and root biomass but also improved the total flavonoid and icariin content, with an increase ranging from 20.24% to 237.97%. Three of the seven DSE fungi caused the inoculated plants to die, and the remaining three DSE strains showed neutral or negative effects on plant growth and the accumulation of bioactive compounds. According to the ITS sequence, DSE8 is congeneric to the genus Leptodontidium. DISCUSSION AND CONCLUSION: The findings indicate that application of DSE8 may be valuable to facilitate the cultivation of E. wushanense with a higher biomass and improved medicinal quality.

Comparative analysis of EPA and DHA in fish oil nutritional capsules by GC-MS.

BACKGROUND: Fish oil is a popular nutritional product consumed in Hong Kong. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are the two main bioactive components responsible for the health benefits of fish oil. Market survey in Hong Kong demonstrated that various fish oil capsules with different origins and prices are sold simultaneously. However, these capsules are labelled with same ingredient levels, namely EPA 180 mg/g and DHA 120 mg/g. This situation makes the consumers very confused. To evaluate the quality of various fish oil capsules, a comparative analysis of the contents of EPA and DHA in fish oil is crucial. METHODS: A gas chromatography-mass spectrometry (GC-MS) method was developed for identification and determination of EPA and DHA in fish oil capsules. A comprehensive validation of the developed method was conducted. Ten batches of fish oil capsules samples purchased from drugstores of Hong Kong were analyzed by using the developed method. RESULTS: The present method presented good sensitivity, precision and accuracy. The limits of detection (LOD) for EPA and DHA were 0.08 ng and 0.21 ng, respectively. The relative standard deviation (RSD) values of EPA and DHA for repeatability tests were both less than 1.05%; and the recovery for accuracy test of EPA and DHA were 100.50% and 103.83%, respectively. In ten fish oil samples, the contents of EPA ranged from 39.52 mg/g to 509.16 mg/g, and the contents of DHA ranged from 35.14 mg/g to 645.70 mg/g. CONCLUSION: The present method is suitable for the quantitative analysis of EPA and DHA in fish oil capsules. There is a significant variation in the contents of the quantified components in fish oil samples, and there is not a linear relationship between price and contents of EPA and DHA. Strict supervision of the labelling of the fish oil capsules is urgently needed.

A systematic review of the botanical, phytochemical and pharmacological profile of Dracaena cochinchinensis, a plant source of the ethnomedicine "dragon's blood".

"Dragon's blood" is the name given to a deep red resin obtained from a variety of plant sources. The resin extracted from stems of Dracaena cochinchinensis is one such source of "dragon's blood". It has a reputation for facilitating blood circulation and dispersing blood stasis. In traditional Chinese medicine, this resinous medicine is commonly prescribed to invigorate blood circulation for the treatment of traumatic injuries, blood stasis and pain. Modern pharmacological studies have found that this resinous medicine has anti-bacterial, anti-spasmodic, anti-inflammatory, analgesic, anti-diabetic, and anti-tumor activities, while it is also known to enhance immune function, promote skin repair, stop bleeding and enhance blood circulation. Various compounds have been isolated from the plant, including loureirin A, loureirin B, loureirin C, cochinchinenin, socotrin-4'-ol, 4',7-dihydroxyflavan, 4-methylcholest-7-ene-3-ol, ethylparaben, resveratrol, and hydroxyphenol. The present review summarizes current knowledge concerning the botany, phytochemistry, pharmacological effects, toxicology studies and clinical applications of this resinous medicine as derived from D. cochinchinenesis.