[Application progress on taste evaluation methods for oral preparations].

Taste is an important factor affecting the medicinal properties of oral preparations and patient compliance with medication, and also an important evaluation index for oral preparation design and clinical application. How to characterize the taste objectively, accurately, simply, and efficiently is a bottleneck problem that restricts the taste design, development, and utilization of oral preparations. At present, the commonly used taste assessment methods for oral preparations are traditional human taste panel, electronic tongue, animal preference test, in vitro release study, and electrophysiological test. The traditional human taste panel is the first choice for taste evaluation, but it is limited by poor subjectivity and reproducibility. Therefore, despite some limitations, the other four taste assessment methods have been applied in the pharmaceutical industry as auxiliary methods. This study reviewed the detection principles, applicability, advantages, and disadvantages of the above methods to provide references for the taste correction research and taste assessment of oral preparations, improve patient compliance and the competitiveness of oral preparation products in the industry, and promote the development of oral preparation technologies.

[Quality value transfer of substance benchmarks in Sanpian Decoction].

According to the polarity of different components in Sanpian Decoction, two fingerprints were established. Then the substance benchmark freeze-dried powder of 15 batches of Sanpian Decoction was prepared, followed by the determination of the fingerprints, index component content, and dry extract rates, the identification of attribution of characteristic peaks, and the calculation of similarities between these fingerprints and the reference(R), the content and transfer rate ranges of ferulic acid, sinapine thiocyanate, liquiritin, and glycyrrhizic acid, and the dry extract rate range. The results showed that the similarities of 15 batches of the substance benchmark fingerprints with R were all greater than 0.900.Further summarization of the characteristic peaks revealed that there were a total of 20 characteristic peaks in fingerprint 1, among which, eight were from Sinapis Semen, four from Paeoniae Radix Alba, six from Chuanxiong Rhizoma, and two from Glycyrrhizae Radix et Rhizoma. A total of 16 characteristic peaks were observed in fingerprint 2, including one from Sinapis Semen, three from Paeoniae Radix Alba, eight from Chuanxiong Rhizoma, and four from Glycyrrhizae Radix et Rhizoma. The average dry extract rate of 15 batches of substance benchmarks was 18.25%, with a dry extract rate range of 16.28%-20.76%. The index component content and transfer rate ranges were listed as follows: 0.15%-0.18% and 38.81%-58.05% for ferulic acid; 0.26%-0.42% and 36.51%-51.02% for sinapine thiocyanate; 0.09%-0.15% and 48.80%-76.61% for liquiritin; 0.13%-0.24% and 23.45%-35.61% for glycyrrhizic acid. The fingerprint, dry extract rate, and index component content determination was combined for analyzing the quality value transfer of substance benchmarks in the classic prescription Sanpian Decoction.The established quality evaluation method for the substance benchmarks was stable and feasible, which has provided a basis for the quality control of Sanpian Decoction and the follow-up development of related preparations.

[Analysis on quality value transmitting of substance benchmark of Houpo Wenzhong Decoction].

By preparing 15 batches of lyophilized powder samples of substance benchmark in Houpo Wenzhong Decoction,the fingerprint,index component content and extract rate were determined,and the characteristic peaks,the range of similarity with the reference map,the content range and transfer rate range of magnolol,hesperidin,glycyrrhizic acid and pinocembrin,the extract rate range and the change range were clarified. The results showed that the similarity between the fingerprint of substance benchmark and the reference map R generated from the 15 batches of substance benchmark samples was higher than 0. 90. The assignment of the characteristic peaks in the full prescription's fingerprint of the herbs except Poria cocos was clarified. Nineteen characteristic peaks were assigned,and 12 characteristic peaks were assigned by the reference substance,of which 4 were from Magnolia ocinalis Cortex,5 from Exocarpium Citri Rubrum,2 from Radix aucklandiae,3 from Glycyrrhiza Radix et Rhizoma,4 from Semen Alpiniae Katsumadai,and one from Rhizoma Zingiberis and Zingiber officinale Roscoe. The index component content range and transfer rate range were 0. 80%-1. 14% and 20. 25%-39. 61% for hesperidin,0. 49%-0. 79% and 23. 09%-33. 87%for glycyrrhizic acid,0. 03%-0. 07% and 3. 55%-10. 09% for pinocembrin,0. 15%-0. 38% and 8. 08%-24. 35% for magnolol. The extract rate range and the change range were22. 60%-25. 57% and 12. 67%-23. 68% respectively. In this study,we introduced the concepts of index component content,fingerprint,extract rate,explored the transfer relation of quality value transmitting of substance benchmark in Houpo Wenzhong Decoction,and initially established the quality standard of Houpo Wenzhong Decoction,all of which would provide ideas for the development and research of similar prescriptions.

X-ray irradiation synthesis of PEG-coated Au-Pd nanoparticles.

We demonstrate that the combination of x-ray irradiation and capping by polyethylene glycol (PEG) produces excellent flexibility in controlling the structure of Au-Pd nanoparticles while preserving their catalytic performance. We specifically adopted two different fabrication methods: co-reduction and seed-assisted reduction. In both cases, precursor composition plays an important role in controlling the phases and size of the bimetallic nanoparticles. The optimal catalytic performance is obtained with the highest Pd concentration and when the nanoparticles consist of a Au core and a Pd shell.

Bioethanol production from the dry powder of Jerusalem artichoke tubers by recombinant Saccharomyces cerevisiae in simultaneous saccharification and fermentation.

It has been found that recombinant Saccharomyces cerevisiae 6525 can produce high concentration of ethanol in one-step fermentation from the extract of Jerusalem artichoke tubers or inulin. However, the utilization rate of raw materials was low and the fermentation process was costly and complicated. Therefore, in this study, after the optimum processing conditions for ethanol production in fed-batch fermentation were determined in flask, the recombinant S. cerevisiae 6525 was first used to produce ethanol from the dry powder of Jerusalem artichoke tubers in 5-L agitating fermentor. After 72 h of fermentation, around 84.3 g/L ethanol was produced in the fermentation liquids, and the conversion efficiency of inulin-type sugars to ethanol was 0.453, or 88.6 % of the theoretical value of 0.511. This study showed high feasibility of bioethanol industrial production from the Jerusalem artichoke tubers and provided a basis for it in the future.

Physiological and biochemical responses of Ulva prolifera and Ulva linza to cadmium stress.

Responses of Ulva prolifera and Ulva linza to Cd(2+) stress were studied. We found that the relative growth rate (RGR), Fv/Fm, and actual photochemical efficiency of PSII (Yield) of two Ulvaspecies were decreased under Cd(2+) treatments, and these reductions were greater in U. prolifera than in U. linza. U. prolifera accumulated more cadmium than U. linza under Cd(2+) stress. While U. linza showed positive osmotic adjustment ability (OAA) at a wider Cd(2+) range than U. prolifera. U. linza had greater contents of N, P, Na(+), K(+), and amino acids than U. prolifera. A range of parameters (concentrations of cadmium, Ca(2+), N, P, K(+), Cl(-), free amino acids (FAAs), proline, organic acids and soluble protein, Fv/Fm, Yield, OAA, and K(+)/Na(+)) could be used to evaluate cadmium resistance in Ulva by correlation analysis. In accordance with the order of the absolute values of correlation coefficient, contents of Cd(2+) and K(+), Yield, proline content, Fv/Fm, FAA content, and OAA value of Ulva were more highly related to their adaptation to Cd(2+) than the other eight indices. Thus, U. linza has a better adaptation to Cd(2+) than U. prolifera, which was due mainly to higher nutrient content and stronger OAA and photosynthesis in U. linza.

[Expressions of SIgA and alpha 1-AR in benign prostatic hyperplasia combined with chronic prostatitis and their implications].

OBJECTIVE: To explore the expressions of SIgA and alpha l-AR in benign prostatic hyperplasia (BPH) complicated by chronic prostatitis (CP) and their implications. METHODS: According to the preoperative findings of expressed prostatic secretion (EPS), transrectal prostate ultrasonography, prostate-specific antigen (PSA), international prostate symptom score (IPSS), clinical symptoms, chronic pelvic pain syndrome (CPPS) and postoperative histopathology, 62 cases of BPH pathologically confirmed after transurethral plasma kinetic resection of the prostate (PKRP) were divided into a BPH group (n = 32) and a BPH + CP group (n = 30). The expressions of SIgA and alpha 1-AR in the prostate tissue were determined by immunohistochemistry and PT-PCR. RESULTS: Of the 62 cases, 30 were found to be BPH + CP, and the other 32 to be BPH. The expressions of SIgA and alpha1-AR were significantly higher in the BPH + CP than in the BPH group (0.380 8 +/- 0.144 3 vs 0.295 4 +/- 0.008 4 and 0.440 5 +/- 0.104 1 vs 0.383 2 +/- 0.013 6, P < 0.05). CONCLUSION: The upregulated expressions of SIgA and alpha1-AR expression in BPH complicated by CP suggest a certain association between CP and BPH, and that inflammation may be a pathogenic factor of BPH and correlate with its pathological development.

Therapeutic effects of Chinese medicine Di-Long (Pheretima vulgaris) on rheumatoid arthritis through inhibiting NF-κB activation and regulating Th1/Th2 balance.

Chinese medicine Di-Long, the dried body of Pheretima vulgaris (Chen) has been used for the treatment of joint inflammation, arthralgia and numbness of limbs for many years. This study was to investigate the anti-rheumatoid arthritis (RA) effects of Di-Long and to explore its possible mechanisms. The identification and quantification of representative components in Di-Long extracts (DL) were carried out by HPLC analysis. The anti-RA effects and mechanisms of DL were studied in CIA mice, RAW 264.7 macrophages and spleen T lymphocytes. The Th1/Th2 cell ratio in CIA mice spleens were determined by Flow cytometry. The cytokine levels were determined by ELISA method. The expressions of p-NF-κB p65 in ankle joints of CIA mice were detected by Immunohistochemistry analysis. The phosphorylation of NF-κB signaling pathway in RAW 264.7 macrophages and expressions of T-bet and GATA-3 in CIA mice spleens were determined by Western blots. The treatment with DL significantly decreased the paw thickness, arthritis scores and inflammatory cells infiltration in CIA mice. The TNF-α, IL-6 concentrations in both mice serum and macrophages secretion were markedly reduced with the treatment of DL, as well as the phosphorylation of NF-κB pathway. DL inhibited the expressions of T-bet and GATA-3 and decreased Th1/Th2 cells ratio in CIA mice spleens. DL reduced IFN-γ, IL-2 levels in mice serum and spleen T lymphocytes, and increased IL-4 levels in CIA mice serum. Chinese medicine Di-Long have significant anti-RA effects. The mechanisms might be inhibiting the activation of NF-κB signaling pathway and regulating the balance of Th1/Th2 cells.

Detecting small lung tumors in mouse models by refractive-index microradiology.

Refractive-index (phase-contrast) radiology was able to detect lung tumors less than 1 mm in live mice. Significant micromorphology differences were observed in the microradiographs between normal, inflamed, and lung cancer tissues. This was made possible by the high phase contrast and by the fast image taking that reduces the motion blur. The detection of cancer and inflammation areas by phase contrast microradiology and microtomography was validated by bioluminescence and histopathological analysis. The smallest tumor detected is less than 1 mm(3) with accuracy better than 1 × 10(-3) mm(3). This level of performance is currently suitable for animal studies, while further developments are required for clinical application.

[Analysis of the mineral element contents of axenic and natural Dunaliella salina].

The contents of eleven mineral elements, including Mg, Fe, K, Ca, Na, Mn, Zn, Cu, Ni, Cd and Cr contents of axenic and natural Dunaliella salina and their culture supernatants in the different period of exponential phase were determined with flame atomic absorption spectrophotometer(AAS). The results show as follows: (1) The contents of Mg, Fe, K, Ca, and Na are between 1 and 10 mg x g(-1). The contents of Zn, Cu, Mn, and Ni are between 0.1 and 1 mg x g(-1). There are little Cd and Cr in the microalgae. (2) The changes in the content of mineral elements of axenic and natural Dunaliella salina during different phases are almost the same. The contents of Mg, Fe, K, Ca, Na, Mn and Cu decreased along with the growth of the microalgae, especially the content of Ca. The contents of Mg, Fe, K, Ca and Na in the culture supernatants keep stable in the culture process and have no distinct difference among axenic and natural Dunaliella salina. But the contents of Cu and Mn in the culture supernatants increased greatly in the middle and end of exponential phase. (3) The contents of Mg, K, Cu, and Ni show no significant differences in axenic and natural microalgae. The contents of Fe, Ca, Na and Zn in the natural microalgae decreased greatly in the middle of exponential phase and were less than in axenic one, but increased at the end of exponential phase and were higher than in axenic one. These results provide reference for further to applying the resource of Dunaliella salina and studying the relationship of microalgae and associated bacteria in the culture.

Simple dose rate measurements for a very high synchrotron X-ray flux.

Dose measurements based on methylene blue (MB) bleaching, widely used for ultraviolet light, can also be applied to X-rays including very high flux levels. This method has been tested by using both MB bleaching and Fricke dosimetry for a conventional monochromatic X-ray source and then for 'white-beam' synchrotron radiation. The results show that MB bleaching dosimetry can easily measure X-ray doses up to at least 10(5) Gy s(-1), as long as the MB concentration is sufficiently high. This condition can be verified from the deviations from linearity of the bleaching versus exposure time.

Escin, a natural mixture of triterpene saponins, exhibits antitumor activity against hepatocellular carcinoma.

Escin, a mixture of triterpene saponins extracted from Aesculus wilsonii Rehd., was used to analyze the antitumor effect in hepatocellular carcinoma in vivo and in vitro. At a dose of 2.8 mg/kg, escin had a rather high inhibition ratio (43.5 %) on mice H22 tumor growth in vivo. The results of the SRB cell viability assay showed that escin could induce significant concentration- and time-dependent inhibition of HepG (2) cell viability. Disruption of the G (1)/S phase of cell cycle progression accompanied by the induction of apoptosis were also observed in HepG (2) cells following escin treatment. The results of pulse-field gel electrophoresis and Western blot analysis show the induction of caspase-independent apoptosis by escin. This study provides evidence that escin induces cell cycle checkpoint arrest and caspase-independent cell death in HepG (2) cells, in support of its efficacious potential as a chemopreventive agent.

Physiological energetics of the ascidian Styela clava in relation to body size and temperature.

The ascidian Styela clava is widely distributed in northern China and is thought to be important in the functioning of estuarine systems. This ascidian may experience highly variable physiological conditions, and its physiological responses to these are of interest considering its ecological role. This study presents data on the physiological parameters in relation to body size and temperature (12-28 degrees C) of S. clava. Respiration, excretion, feces, ingestion and absorption energy were positive related to size and its mass exponents (b-values) varied from 0.2930 to 0.7488. Respiration energy increased with increasing, but critical values were found at 20 degrees C for energy of ingestion and absorption, while 24 degrees C for energy in feces and excretion. At the range of 16-24 degrees C, the scope for growth, gross and net growth efficiencies of ascidians increased with increasing temperature. The energy budget equations of different sized ascidians were obtained at different temperatures. Excretion energy shared a minimal fraction in ingestion energy (1.30-2.47%), the ratios of feces energy and respiration energy to ingestion energy were 46.53-64.27% and 10.26-80.75%, respectively. The physiological data obtained in the present study indicated that S. clava could adjust its energy budget according to the environment and its physiological conditions to meet their nutritional and energetic demands. In the range of experimental temperature (12-28 degrees C), 16-20 degrees C was suitable for the rearing of S. clava to achieve optimum development, while deficient metabolic adjustment induced a negative scope for growth of S. clava at 28 degrees C.

[Purification of growth-inhibitor formed by Isochrysis galbana].

The objective of the present study is to isolate and purify the anti-cell bioactive fraction-cell growth-inhibitor from the old cultured liquid of Isochrysis galbana. By means of extraction with ethyl acetate, ultraviolet scan, Sephadex G-15 column chromatography, preparative thin-layer chromatography and high-performance liquid chromatography, the bioactive component was purified. The growth-inhibitor, a kind of crude ethyl acetate extract isolated from the cell-free supernatant of the old culture liquid of Isochrysis galbana, obviously inhibited the cell growth. It was showed that the growth-inhibitor existing in the old cultured liquid of Isochrysis galbana was efficiently extracted with ethyl acetate. The characteristic absorption of the growth-inhibitor was determined by ultraviolet scan and the wavelength of characteristic absorption for the growth-inhibitor was 235 nm. The residue of crude ethyl acetate extract was dissolved in diluted aqueous NaOH, and then was loaded onto Sephadex G-15 column chromatography and eluted with distilled water. Five-mL fractions were collected and monitored by UV absorption at 235 nm. The crude ethyl acetate extract was fractionated by gel filtration on Sephadex G-15 to obtain three fractions. And the three fractions inhibited the growth of Isochrysis galbana. Those active fractions were adjusted to the pH value 2-3, and extracted with ethyl acetate. And then the extracts were concentrated to the befitting volume under reduced pressure at 40 degrees C, and were separated by preparative thin-layer chromatography on silica gel with chloroform. Bands visualized under UV-light (254 and 365 nm) were scraped off and extracted with ethyl acetate, and monitored as well as inhibitory activity against Isochrysis galbana. The extracts were separated into four bands on a preparative thin-layer chromatography plate with chloroform, but only the band at R(f) 0.63 was active. This active fraction was finally purified by high-performance liquid chromatography on ODS with aqueous acetonitrile to produce 4 prominent peaks. The selected optimum chromatographic conditions were ZORBAX Eclipse XDB C18 with aqueous acetonitrile at a flow rate of 0.3 mL x min(-1), and UV detection at 235 nm. This paper would afford very well condition for further isolation and preparation by HPLC and identification of growth-inhibitor formed by Isochrysis galbana.

[Determination of trace elements in Aloe barbadensis Miller irrigated with seawater by atomic absorption spectrophotometry].

The dry leaves of Aloe barbadensis Miller irrigated with seawater were dissolved in nitric acid and then oxygenated by perchloric acid. Nine kinds of trace elements in the samples were determined by atomic absorption spectrophotometry, including calcium, potassium, magnesium, sodium, manganese, zinc, iron, copper and lead, with added lanthanum chloride as releaser to eliminate the interference of co-existent ions. The recoveries were 96.58%-104.31%, and the relative standard deviations of sample determination (10 times) were less than 2%. This method is simple, sensitive and rapid with satisfactory results and good reproducibility. The results indicated that there were rich Ca, Mg, K and Na, and moderate Mn, Zn and Fe elements in the Aloe barbadensis Miller irrigated with seawater. However, the concentrations of Cu and Pb were low. Therefore, Aloe barbadensis Miller irrigated with seawater has officinal and economic values. These results provide data for further research on Aloe barbadensis Miller irrigated with seawater.

[Regulative effects of aquaporin 4 expression by rhein in rhubarb to intestinal epithelial cell line LoVo].

OBJECTIVE: To investigate the effects of rhein on regulating aquaporin4 (AQP4) to LoVo cells cultured with RPMI-1640 medium containing rhein. METHODS: LoVo cells were cultured with RPMI-1640 medium containing different concentration rhein for 24 hours and were cultured with RPMI-1640 containing rhein (20 mg/L) for different time. Four groups were assigned as LoVo cells were cultured respectively with RPMI-1640 medium containing different concentration rhein (40, 20, 10 mg/L and control group), while six groups were assigned as LoVo cells were cultured with RPMI-1640 medium containing rhein (20 mg/L) for different time (3, 6, 12, 24, 48 h and control group). The location of AQP4 protein in LoVo cells was definited by immuocytochemistry dying. Western blotting and semiquantitative RT-PCR were adopted to detect the relative expression of AQP4 protein and mRNA. RESULTS: AQP4 was located mainly in plasma membrane of LoVo cells while partly in cytoplasm. The relative expression of AQP4 protein and mRNA decreased with the increasing of rhein concentration; there was no significant difference of the relative expression of AQP4 in 10 mg/L group compared with that in control group, but it decreased significantly in 40 and 20 mg/L groups. The relative expression of AQP4 in 3 and 6 h groups was lower than that in control group but there was no statistical significance, however that in 12, 24, 48 h groups was lower significantly compared with that in control group. CONCLUSION: Rhein can inhibit the genetic transcription and the translation of AQP4 gene in LoVo cells, which demonstrates that the change of AQP4 expression regulated by rhein may be related to the cathartic effect of rhubarb.

[Effect of total anthraquinone in rheum on aquaporin 2 expression in rat distal colon].

OBJECTIVE: To investigate effect of total anthraquinone in rheum on aquaporin 2 expression in rat distal colon. METHOD: SD rats were randomly divided into control group, low dose group, middle dose group and high dose group. Gavaged to control group, and treated group were administered saline and total anthraquinone in rheum with dosage of 0.14, 2.5, 4.5 g x kg(-1) x d(-1), respectively. All rats were put sacrificed after 5 days and stool in full length colon was gently collected to detect water content stool. Distal colon was removed to detect AQP2 expression with immunohistochemistry, western blot and RT-PCR. RESULT: No diarrhea was found in low dose group and control group, there were not significant difference water content of stool and AQP2 expression between low dose group and control group. However, soft feces and loose stools occurred in diarrheic dose group, loose stools and watery stool appeared in high dose group. Stool water content increased in diarrheic dose group and High dose group, expression of AQP2 decreased evidently in these two groups (P < 0.01). CONCLUSION: Total anthraquinone in rheum can reduce the transcription and translation of AQP2 in rats' distal colon, increase fecal water content, which probably is one of the mechanisms of diarrhea caused by total anthraquinone in rheum.

[Analysis of eleven mineral elements for eight benthic marine diatoms using AAS].

Eleven mineral-elements, Mg, Fe, K, Ca, Mn, Zn, Cu, Ni, Pb, Cr and Cd, for eight benthic marine diatoms were determined by using flame atomic absorption spectrophotometry (AAS). This method is rapid with high precision and accuracy. The relative standard deviation, correlative coefficient and recovery rate are less then 6.85%, 0.9989-0.9999 and 95%-103%, respectively. The results show that there are high mineral-element levels in the eight benthic diatoms, with Mg>Fe>K>Ca> Mn>Zn among them, while the contents of Ni and Cu are poor, and there are little Pb, Cr and Cd in benthic diatoms. The contents of Mg, K and Mn in Navicula seminulum Grun are maximum elements, with (17.2240 +/- 0.0302) mg x g(-1) SD and (1.7885 +/- 0.0939) mg x g(-1) SD, (0.2253 +/- 0.0011) mg x g(-1) SD respectively. There were the most contents of Fe (4.2314 +/- 0.0309) mg x g(-1) SD and Zn (0.1167 +/- 0.0029) mg x g(-1) SD, Cu (0.0227 +/- 0.0007) mg x g(-1) SD and Ni (0.0147 +/- 0.0005) mg x g(-1) SD in Hantzschia amphioxys (Ehr.) Grun. var. leptocephala Ostrup. The element of maximum content in Nitzschia sp. was Ca (6.3537 +/- 0.0412 mg x g(-1) SD). The experimental results indicate that the eight benthic diatom species could prove useful feed species for benthic animal species grown in aquaculture such as abalone, sea urchin and sea cucumber.

Growth and physiological responses of a marine diatom (Phaeodactylum tricornutum) against two imidazolium-based ionic liquids ([C4mim]BF4 and [C8mim]BF4).

Ionic liquids (ILs) have been considered as "green" substitutes for traditional organic solvents in many existing biological and chemical areas. However, they have high solubility and poor biodegradability in water, suggesting that they could become persistent chemical pollutants in aquatic environment. The ability of two widely used imidazolium-based ILs to affect the growth and physiological characteristics of a marine diatom (Phaeodactylum tricornutum) was investigated in this study. The diatom was exposed to different concentrations of 1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim]BF4) and 1-octyl-3-methylimidazolium tetrafluoroborate ([C8mim]BF4) for 96h within a batch-culture system. Results showed that [C4mim]BF4 and [C8mim]BF4 were very stable in seawater during 96h of exposure, and the compounds significantly inhibited the growth of P. tricornutum with 24, 48, 72 and 96h EC50 values of 30.81, 28.53, 39.92, 45.88mgL-1 and 30.17, 23.36, 28.62, 31.37mgL-1, respectively. In addition, the photosynthetic activity and chlorophyll a synthesis of P. tricornutum were inhibited by [C4mim]BF4 and [C8mim]BF4, indicating that the structural integrity of chloroplasts of the diatom may be disrupted or damaged by the two ILs. Compared with that of the controls, reactive oxygen species (ROS) level was increased by 0.65, 1.17, 1.85, 3.13, 2.94 times and 0.55, 1.77, 2.42, 3.45, 3.47 times in 5, 10, 20, 40 and 60mgL-1 [C4mim]BF4 and [C8mim]BF4 treatments, respectively. The excessive ROS may cause lipid peroxidation, shortage of metabolic energy and decline of photosynthetic efficiency, which may be the main reason for toxicity of the two ILs to marine diatoms. To withstand the damaging effects of excessive ROS, remarkable physiological and biochemical responses occurred in treatments with the two ILs to protect the cells of P. tricornutum. Parameters such as soluble protein content, soluble sugar content, and superoxide dismutase (SOD) and peroxidase (POD) activities of the diatom increased significantly with increasing concentrations of the two ILs at 96h of exposure relative to the controls. These findings not only provide strong background for evaluating the ecological risks and toxicity of ILs in marine environment, but also help to unravel the toxic mechanism of the two ILs to marine diatoms.

Isolation and purification of antialgal compounds from the red alga Gracilaria lemaneiformis for activity against common harmful red tide microalgae.

Seven antialgal compounds (1-7) were successfully isolated from the red alga Gracilaria lemaneiformis through a combination of silica gel column chromatography and repeated preparative thin-layer chromatography. On the basis of the spectral data, the compounds were identified as gossonorol (1), 7,10-epoxy-ar-bisabol-11-ol (2), glycerol monopalmitate (3), stigmasterol (4), 15-hydroxymethyl-2, 6, 10, 18, 22, 26, 30-heptamethyl-14-methylene-17-hentriacontene (5), 4-hydroxyphenethyl alcohol (6), and margaric acid (7). These seven compounds were isolated from G. lemaneiformis for the first time, while the compounds 4, 6, and 7 were isolated from marine macroalgae for the first time. Furthermore, a quantitative relationship between the inhibition of algal growth and the concentration of each antialgal compound was determined and important parameters for future practical HAB control, e.g., EC50-96h, were also obtained. The results indicated that isolated compounds 1-7 possess selective antialgal activity against the growth of several red tide microalgae (including Amphidinium carterae, Heterosigma akashiwo, Karenia mikimitoi, Phaeocystis globsa, Prorocentrum donghaiense, and Skeletonema costatum). Their antialgal activity against test red tide microalgae has not been previously reported. Furthermore, the EC50-96h of one or more of the compounds towards the tested red microalgae was not only significantly less than 10 µg/mL but also was smaller than that of the characteristic antialgal agent potassium dichromate. The study demonstrates that compounds 1-7 possess significant application potential as antialgal agents against several harmful red tide microalgae.