山核桃叶中重金属的含量测定分析

采用紫外分光光度法测定了山核桃叶中重金属的含量,分析波长为299 nm。结果表明,山核桃叶中重金属含量为17.264μg/g,线性范围1～20μg,平均加样回收率为99.87%。为进一步开发利用浙江山核桃叶资源提供了科学依据。     

Essential oil of <Emphasis Type="Italic">Laurus nobilis</Emphasis> from Montenegro

Steam distilled oil from the shoots, separated leaves, and stem, as well as from the flower of laurel (Laurus nobilis), grown in Montenegro, were analyzed by GC and GC/MS. The yield of essential oil was as follow: 1.4% in young shoots, 1.5% in the separated leaves, and 0.7% in separated stems. The main constituents of all investigated oils were 1,8-cineole, methyleugenol, and α-terpinyl acetate. Besides, α-pinene, β-pinene, sabinene, and linalool were also present. It was interesting and important for commercial samples of laurel essential oil that there was no significant difference among the essential oil obtained from young shoots and those obtained from leaves and stem. The main constituents of the flower oil were 1,8-cineole (15.7%), β-caryophyllene (9.5%), γ-muurolene (7.1%), α-terpinyl acetate (6.5%), and methyleugenol (3.9%). Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 337–339, July–August, 2007.     

New pentacyclic triterpene saponins with strong anti-leishmanial activity from the leaves of Maesa balansae

Six new triterpene saponins bearing an oxygen bridge between C-13 and C-28 and with pronounced anti-leishmanial activity were isolated from the methanolic extract of leaves of the Vietnamese medicinal plant Maesa balansae. The structure was established on the basis of detailed NMR (COSY, NOESY, HMQC, HMBC, TOCSY and DEPT) and FAB-MS studies along with chemical degradation. All saponins identified contained the same pentaglycosidic side chain, but a different esterification pattern on the triterpenoid part. Biological evaluation of the individual compounds against visceral leishmaniasis (Leishmania infantum amastigotes) revealed a much better activity in vitro compared to the reference compound Pentostam^®, which is currently used as first-line treatment for leishmaniasis.     

云南凤庆绿茶自溶液中对Ag^＋的吸附

研究了凤庆绿茶自溶液中对Ａｇ＋的吸附特性。绘制了吸附速度曲线，并求出了Ｌａｎｇ－ｍｕｉｒ和Ｆｒｅｕｎｄｌｉｃｈ方程中的有关参数。考察了温度、ｐＨ值对吸附的影响以及酸、碱和不同配合剂对Ａｇ＋的解吸附作用。结果表明，吸附具有以化学吸附为主的Ｌａｎｇｍｕｉｒ单分子层吸附特征，０．１ｍｏｌ／ＬＮａ２Ｓ２Ｏ３溶液可定量地解吸Ａｇ＋     

The impact of ultrasound and steam blanching pre-treatments on the drying kinetics,energy consumption and selected properties of parsley leaves

In current study the influence of ultrasound pre-treatment and drying conditions (microwave power, air temperature) was analysed by the means of drying kinetics, energy consumption and selected quality properties of dried parsley leaves. Ultrasound treatment (US) was compared with conventional treatment – steam blanching. In comparison to untreated material, ultrasound applied at 21 kHz, 12 W/g, contributed to significant reduction of the drying time up to 29.8%. Moreover, the energy expenditures were reduced maximally by 33.6% for parsley dried at 30 °C and 300 W. For this sample the colour retention was the highest, as well. In turn, steam treated parsley was dried maximally by 28.9% faster and thus specific energy consumption decreased to 72.0% of the value for intact leaves when 20 °C and 300 W were set. The influence of pre-drying treatment on the quality properties depended on the drying conditions. Pre-drying treatment (US, blanching) did not affect the lutein content significantly, whereas the most considerable increase of chlorophyll a and b resistance and their relative concentration (Chl a/b ratio) was achieved in US-treated leaves dried at 30 °C and 100 W. The utilisation of drying pre-treatment and dehydration parameters should be considered with respect to further utilisation of dried parsley leaves. Nonetheless, sonication is worth to be taken into account due to a significant reduction of energy expenditures and an improvement of resistance of bioactive components.     

Fingerprint analysis and quality consistency evaluation of flavonoid compounds for fermented Guava leaf by combining high‐performance liquid chromatography time‐of‐flight electrospray ionization mass spectrometry and chemometric methods

Guava leaves are used in traditional herbal teas as antidiabetic therapies. Flavonoids are the main active of Guava leaves and have many physiological functions. However, the flavonoid compositions and activities of Guava leaves could change due to microbial fermentation. A high‐performance liquid chromatography time‐of‐flight electrospray ionization mass spectrometry method was applied to identify the varieties of the flavonoids in Guava leaves before and after fermentation. High‐performance liquid chromatography, hierarchical cluster analysis and principal component analysis were used to quantitatively determine the changes in flavonoid compositions and evaluate the consistency and quality of Guava leaves. Monascus anka Saccharomyces cerevisiae fermented Guava leaves contained 2.32‐ and 4.06‐fold more total flavonoids and quercetin, respectively, than natural Guava leaves. The flavonoid compounds of the natural Guava leaves had similarities ranging from 0.837 to 0.927. The flavonoid compounds from the Monascus anka S. cerevisiae fermented Guava leaves had similarities higher than 0.993. This indicated that the quality consistency of the fermented Guava leaves was better than that of the natural Guava leaves. High‐performance liquid chromatography fingerprinting and chemometric analysis are promising methods for evaluating the degree of fermentation of Guava leaves based on quality consistency, which could be used in assessing flavonoid compounds for the production of fermented Guava leaves.     

Six new metabolites produced by Colletotrichum aotearoa 09F0161, an endophytic fungus isolated from Bredia oldhamii

Six new compounds, colletobredins A–D (1–4) and colletomelleins A and B (5 and 6), along with 12 previously identified compounds, were isolated from the culture broth of Colletotrichum aotearoa BCRC 09F0161, a fungal endophyte residing in the leaves of an endemic Formosan plant Bredia oldhamii Hook. f. (Melastomataceae). The structures of the new compounds were established by spectroscopic methods, including UV, IR, HR-ESIMS and extensive 1D and 2D NMR techniques. The effects of some isolates on the inhibition of nitric oxide (NO) production in lipopolysaccharide-activated murine macrophage RAW264.7 cells were evaluated. All these compounds inhibited NO production in activated macrophages without any cytotoxicity at a concentration of 100 μM. Of these isolates, 1 showed weak NO inhibitory activity with IC₅₀ value of 182.2 μM. To the best of our knowledge, this is the first report on isochroman glycoside metabolites (1–4) from the genus Colletotrichum.     

基于高光谱成像技术的不同时期番茄植株的快速无损判别研究

利用近红外高光谱成像技术对不同浓度盐胁迫下的番茄叶片进行了定性判别。采集192个叶片样本的平均光谱反射率数据,并对原始光谱数据分别进行多元散射校正（MSC）、标准正态化（SNV）、正交信号校正（OSC）、相关优化偏移（COW）4种预处理,建立了偏最小二乘回归（PLSR）模型。建模结果显示：OSC预处理光谱的建模效果最优。分别采用间隔变量迭代空间收缩法（iVISSA）、间隔随机蛙跳法（IRF）、遗传偏最小二乘算法（GAPLS）、竞争性自适应加权算法（CARS）、变量组合集群分析（VCPA）等方法提取特征波长,建立PLSR模型。结果表明：VCPA提取特征波长所建立的模型最优。将VCPA法提取的11个特征波长（945、975、990、1 002、1 005、1 067、1 204、1 326、1 595、1 642、1 660 nm）用于建立番茄叶片定性判别预测模型,最优预测模型的决定系数（R2P）与预测均方根误差（RMSEP）分别为0.917、0.456。该研究为在线监测植物长势提供了技术支撑。     

The biological response of Carica papaya leaves extract to saponin reduction (O/W) emulsion on human bronchial epithelium cell (BEAS-2B)

Carica papaya leaf has a potentially well-known therapeutic effect in accelerating human blood platelet counts against dengue fever and dengue haemorrhagic fever. However, consuming the extract was considered troublesome due to its bitter taste. The fresh papaya leaves were extracted into two types of preparation: a) Fresh Papaya Leaves Extract (FPL) and b) Papaya Leaves with Saponin Reduction Extract (PLSR). This was followed by the determination of the best edible O/W emulsion formulation of both different extracts with virgin coconut oil (VCO) and whey protein (WP) as surfactant. Through Ternary Phase Diagram (TPD), the optimum ratio (w/w) of FPL/PLSR: VCO: WP were 63: 16: 21 and 65: 16: 19 respectively. Both formulas were examined for their physicochemical properties including pH, creaming index (CI), contact angle and droplet size measurement. The human bronchial epithelium cell (BEAS-2B) was treated using both emulsions for 72 hrs of cell growth response (EC₅₀). The result shows that both FPL and PLSR formulations were slightly acidic and exhibited stable emulsion with no creaming formation (CI) up to 24 hrs of storage (25 ℃). Next, FPL emulsion shows 3 times higher wettability and 4 times bigger nanoparticle size than PLSR. These properties can affect the emulsion absorptivity in the targeted cell microenvironment. Remarkably, the BEAS-2B cell viability (%) for each emulsion was relatively elevated within 24 hrs and increased to more than 100 % at 48 and 72 hrs of exposure. This might hugely represent its potential in repairing damaged blood vessels due to dengue haemorrhagic fever. Besides, the EC₅₀ value also indicated low levels of concentration needed to exponentially increase cell growth and safe for dengue fever treatment. For that reason, the recommended effective dosage by the Ministry of Health (Malaysia) (MOH) for both FPL and PLSR emulsions is two tablespoons twice a day for three consecutive days of treatment (equally to the effective dosage of 102 g extract).     

Anti-Escherichia coli activity of extracts from Schinus terebinthifolius fruits and leaves

Ethanol extracts obtained from Schinus terebinthifolius Raddi fruits and leaves were active against Escherichia coli with MIC of 78 μg mL^?1 for both extracts. Phytochemical analyses revealed a major presence of phenolic acids, tannins, fatty acids and acid triterpenes in the leaves and phenolic acids, fatty acids, acid triterpenes and biflavonoids in the fruits. Major compounds isolated from the plant, such as the acid triterpene schinol, the phenolic acid derivative ethyl gallate and the biflavonoids agathisflavone and tetrahydroamentoflavone, showed very little activity against E. coli. Bioautography of the ethanol extracts on silica gel plate showed inhibition zones for E. coli. They were removed from the plate and the compounds identified as a mixture of myristic, pentadecanoic, palmitic, heptadecanoic, stearic, nonadecanoic, eicosanoic, heneicosanoic and behenic fatty acids.