超临界二氧化碳萃取柿叶黄酮的工艺研究

本文研究了超临界流体萃取柿叶总黄酮苷类化合物的影响因素,并对生产工艺进行了优化设计。试验结果表明:萃取时压力、温度、时间、CO2流量对萃取率的影响程度依次递减。最佳工艺条件为:萃取压力30MPa、萃取温度50℃、萃取时间3h、CO2流量30kg·h-1。用超临界流体萃取法得到的柿叶总黄酮苷类化合物萃取物纯度高,无异味,色泽金黄。     

Extraction of essential oils from Algerian myrtle leaves using instant controlled pressure drop technology

In the present work, the new extraction process of Détente Instantanée Contrôlée DIC (French, for instant controlled pressure drop) was studied, developed, quantitatively and qualitatively compared to the conventional hydrodistillation method for the extraction of essential oils from Algerian myrtle leaves. DIC was used as a thermomechanical treatment, DIC subjecting the product to a high-pressure saturated steam. The DIC cycle ends with an abrupt pressure drop towards vacuum, and this instantly leads to an autovaporization of myrtle volatile compounds. An immediate condensation in the vacuum tank produced a micro-emulsion of water and essential oils. Thus, an ultra-rapid cooling of residual leaves occurred, precluding any thermal degradation. An experimental protocol was designed with 3 independent variables: saturated steam pressure between 0.1 and 0.6 MPa, resulting in a temperature between 100 and 160 °C, a total thermal processing time between 19 and 221 s, and between 2 and 6 DIC cycles. The essential oils yield was defined as the main dependent variable. This direct extraction gave high yields and high quality essential oil, as revealed by composition and antioxidant activity (results not shown). After this treatment, the myrtle leaves were recovered and hydrodistilled in order to quantify the essential oil content in residual DIC-treated samples. Scanning electron microscope (SEM) showed some modification of the structure with a slight destruction of cell walls after DIC treatment.     

Extraction and preparation of 5-lipoxygenase and acetylcholinesterase inhibitors from Astragalus membranaceus stems and leaves

In this study, an efficient method that employs 5-lipoxygenase and acetylcholinesterase as biological target molecules in receptor–ligand affinity ultrafiltration–liquid chromatography was developed for the screening of enzyme inhibitors derived from the Astragalus membranaceus stems and leaves. The effects of the extraction time, number of extraction cycles, ethanol concentration, and liquid–solid ratio on the total yield of the target compounds were investigated using response surface methodology, and the bioactive components were isolated using a combination of semi-preparative high-performance liquid chromatography and high-speed countercurrent chromatography via a two-phase solvent system consisting of n-hexane–ethyl acetate–methanol–water (1:6:2:6, v/v/v/v). Subsequently, 10 naturally-occurring bioactive components in the Astragalus membranaceus stems and leaves, including wogonin, ononin, isoquercitrin, calycosin-7-glucoside, 3-hydroxy-9,10-dimethoxyptercarpan, hyperoside, 7,2′-dihydroxy-3′,4′-dimethoxyisoflavan, baicalein, calycosin, and soyasaponin, were screened using affinity ultrafiltration to determine their potential effects against Alzheimer's disease. Consequently, all target compounds had purities higher than 95.0%, and the potential anti-Alzheimer's disease effect of the obtained bioactive compounds was verified using molecular docking analysis. Based on the results, the back-to-back screening of complex enzyme inhibitors and separation of the target bioactive compounds using complex chromatography could provide a new approach to the discovery and preparation of natural active ingredients.     

广西产湿地松松针挥发性成分的提取及分析

采用水蒸气蒸馏法提取湿地松针叶挥发油的油相部分,用乙醚萃取法提取蒸馏残液中的水溶性挥发性组分,利用气相色谱-质谱联用分析比较二者的化学成分。湿地松挥发油油相部分的得油率为0.277%,共分离出86个色谱峰,鉴定了其中的49种化合物,占总含量的92.12%,油相部分的主要成分有β-蒎烯（14.29%）、吉马烯（12.87%）、α-蒎烯（6.79%）、β-石竹烯（6.15%）、α-石竹烯（1.58%）;水溶性部分的得油率为0.0682%,鉴定了其中的6种化合物,占水溶性部分总量的60.72%,α-松油醇（24.61%）为水溶性部分的主要成分。由于增加了水溶部分精油的提取,湿地松松针挥发油总的产油率提高到0.3452%,提高率达24.62%。     

Extraction and isolation of shikimic acid from Ginkgo biloba leaves utilizing an ionic liquid that dissolves cellulose

Shikimic acid, the starting material in the commercial synthesis of oseltamivir phosphate (Tamiflu?), was efficiently extracted and isolated from Ginkgo biloba leaves utilizing the ionic liquid 1-butyl-3-methylimidazolium chloride ([bmim]Cl), which dissolves cellulose.     

Triterpenoids from Psidium guajava leaves

Three pentacyclic triterpenoids including one new guajavanoic acid (2) and two known obtusinin (1) and goreishic acid I (3) have been isolated from the leaves of Psidium guajava. The new constituent 2 has been characterized as 2alpha-hydroxy-3beta-p-E-coumaroyloxyurs-12, 18-dien-28-oic acid through 1H-NMR and 13C-NMR (broad band and DEPT). This is the first report of isolation of compound 1 and 3 from the genus Psidium.     

Lipids from leaves ofEphedra equizetina

The content and composition by class and fatty acid of neutral (NL), glyco- (GL), and phospholipids (PL) in leaves ofEphedra equizetina Bunge (Ephedraceae) are determined. The acid composition of NL, GL, and PL includes saturated 12∶0–32∶0 acids and unsaturated 15∶1, 16∶1, 18∶1, 18∶2, and 18∶3 acids. Unsaponified components of the total lipids also contained biologically active substances such as α-tocopherol, carotenoids, high-molecular-weight fatty alcohols, triterpenes, and sterols. Academician S. Yu. Yunusov Institute of the Chemistry of Plant Substances. Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (371) 120 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 718–721, November–December, 1999.     

Constituents from leaves of Quillaja brasiliensis

A new abietane diterpene, the 19-O-beta-D-glucopyranoside of 16-hydroxylambertic acid was isolated from the leaves of Quillaja brasiliensis together with a known prosapogenin (3-O-beta-D-glucuronopyranosyl-quillaic acid), quercetin, and rutin. The new compound was identified by chemical and spectroscopic methods.     

马尾松和湿地松松针挥发性成分的提取及GC-MS比较分析

采用水蒸气蒸馏法提取马尾松和湿地松松针叶挥发油的油相部分,用乙醚萃取法提取蒸馏残液中的水溶性挥发性组分,利用气相色谱-质谱联用分析比较它们的化学成分。由于增加了水溶性部分的提取,马尾松和湿地松挥发油总的得油率提高到0.4709%和0.3452%,提高率分别达19.17%和24.62%。马尾松挥发油的油相成分和水溶性成分组成部分相同,但含量相差较大;而湿地松针叶精油的油相和水相部分成分组成差别较大;马尾松和湿地松相比较,针叶精油（油相部分）的主要化学成分大致相同,都是以单萜和倍半萜为主,但在含量上有较大差别。