Two new asterosaponins from the starfish Asterias rubens: application of a cryogenic NMR probe head

We report two new asterosaponins from the Baltic starfish Asterias rubens along with their ¹H and ¹³C NMR data. The compounds were isolated after on‐flow liquid chromatography–NMR–mass spectrometry screening indicated that they had not been identified before. The one‐ and two‐dimensional NMR experiments used to elucidate the structures were recorded using a 5 mm cryogenic probe head. The advantages of cryogenic probes for this kind of examination in comparison with conventional probe heads are discussed. Copyright © 2003 John Wiley & Sons, Ltd.     

紫外分光光度法测定海星皂甙的含量

海星皂甙与浓硫酸反应生成α,β 不饱和酮,在277nm处产生特征吸收峰,据此建立了紫外分光光度法测定海星皂甙含量的分析方法。该法测定皂甙的百分吸光系数E1%为149mL·g-1·cm-1,线性范围10～50μg/mL,检出限为0.37μg/mL。方法1cm,λmax用于不同种类海星组织中的皂甙含量测定,简单快速,稳定性好,精密度高,结果令人满意。     

反相高效液相色谱法同时测定罗氏海盘车中的7种核苷化合物

建立了罗氏海盘车中7种核苷化合物的反相高效液相色谱分析测定方法。采用超声波辅助提取,选用两根不同的C18色谱柱串联,以甲醇和0.2%(体积分数)乙酸/水溶液为流动相梯度洗脱分离。优化的色谱条件为: 柱温为室温,检测波长为260 nm,流速为0.8 mL/min,进样量为20 μL。结果表明,7种核苷化合物在一定的浓度范围内线性关系良好,次黄嘌呤和胸苷的线性范围为0.65～40 mg/L,尿苷、黄嘌呤和肌苷的线性范围为0.80～40 mg/L,胸腺嘧啶的线性范围为1.15～40 mg/L,鸟苷的线性范围为0.50～40 mg/L。样品中7种核苷化合物的加标回收率为90.00%～105.00%,相对标准偏差为0.72%～3.23%。该方法操作简便、灵敏度高、重复性好,回收率高,适用于罗氏海盘车中7种核苷类成分的同时分析,也可用于罗氏海盘车的质量控制和综合评价。     

Measuring mercury in wood: challenging but important

Mercury (Hg) in tree wood has been overlooked, in part because concentrations are so low as to be below detection limits of some analytical methods, but it is potentially important to forest ecosystem processes and budgets. We tested methods for the preparation and determination of Hg in tree wood by analysing samples of four tree species at the Hubbard Brook Experimental Forest, New Hampshire, USA, using thermal decomposition, catalytic conversion, amalgamation and atomic absorption spectrophotometry (USEPA Method 7473). Samples that were freeze-dried or oven-dried at 65°C were suitable for determination of Hg, whereas oven-drying at 103°C resulted in Hg losses, and air-drying resulted in Hg gains, presumably due to sorption from indoor air. Mean (±SE) concentrations of Hg tree bole wood were 1.75 ± 0.14 ng g^?1 for American beech, 1.48 ± 0.23 ng g^?1 for sugar maple, 3.96 ± 0.19 ng g^?1 for red spruce and 4.59 ± 0.06 ng g^?1 for balsam fir. Based on these concentrations and estimates of wood biomass by species based on stand inventory, we estimated the Hg content of wood in the reference watershed at Hubbard Brook to be 0.32 g ha^?1, twice the size of the foliar Hg pool (0.15 g ha^?1). Mercury in wood deserves more attention and is feasible to measure using appropriate techniques.     

The Lebanese Red Algae Jania rubens: Promising Biomolecules against Colon Cancer Cells

Colorectal cancer (CRC) is ranked the second most lethal type of tumor globally. Thus, developing novel anti-cancer therapeutics that are less aggressive and more potent is needed. Recently, natural bioactive molecules are gaining interest as complementary and supportive antineoplastic treatments due to their safety, effectiveness, and low cost. Jania rubens (J. rubens) is a red coral seaweed abundant in the Mediterranean and bears a significant pharmacological essence. Despite its therapeutic potential, the natural biomolecules extracted from this alga are poorly identified. In this study, the proximal analysis revealed high levels of total ash content (66%), 11.3% proteins, 14.5% carbohydrates, and only 4.5% lipids. The elemental identification showed magnesium and calcium were high among its macro minerals, (24 ± 0.5 mg/g) and (33 ± 0.5 mg/g), respectively. The Chlorophyll of J. rubens was dominated by other pigments with (0.82 ± 0.02 mg/g). A 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay identified effective antioxidant activity in various J. rubens extracts. More importantly, a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) tetrazolium reduction and wound healing assays indicate that organic extracts from J. rubens significantly counteract the proliferation of colon cancer cell lines (HCT-116 and HT-29) and inhibit their migratory and metastatic properties in a dose and time-dependent manner. Overall, this study provides insight into the physicochemical properties of red seaweed, J. rubens, and identifies its significant antioxidant, cytotoxic, and anti-migratory potential on two colorectal cell lines, HCT-116 and HT-29.