Microwave-assisted extractions of active ingredients from plants

Microwave-assisted extraction (MAE) is widely employed in the analysis and the extraction of active compounds from plants. This review summarizes the research done during the last decade on the MAE of active ingredients from plants. Advances and modifications to improve the performance of MAE are presented and discussed in detail. Modified MAE such as vacuum microwave-assisted extraction (VMAE), nitrogen-protected microwave-assisted extraction (NPMAE), ultrasonic microwave-assisted extraction (UMAE), dynamic microwave-assisted extraction (DMAE) and other advancements in MAE are also detailed in this article. In addition, the microwave extraction procedures and the important parameters influencing its performance are also included, together with the advantages and the drawbacks of each MAE techniques.     

Screening and Production Study of Microbial Xylanase Producers from Brazilian Cerrado

Hemicelluloses are polysaccharides of low molecular weight containing 100 to 200 glycosidic residues. In plants, the xylans or the hemicelluloses are situated between the lignin and the collection of cellulose fibers underneath. The xylan is the most common hemicellulosic polysaccharide in cell walls of land plants, comprising a backbone of xylose residues linked by β-1,4-glycosidic bonds. So, xylanolytic enzymes from microorganism have attracted a great deal of attention in the last decade, particularly because of their biotechnological characteristics in various industrial processes, related to food, feed, ethanol, pulp, and paper industries. A microbial screening of xylanase producer was carried out in Brazilian Cerrado area in Selviria city, Mato Grosso do Sul State, Brazil. About 50 bacterial strains and 15 fungal strains were isolated from soil sample at 35 °C. Between these isolated microorganisms, a bacterium Lysinibacillus sp. and a fungus Neosartorya spinosa as good xylanase producers were identified. Based on identification processes, Lysinibacillus sp. is a new species and the xylanase production by this bacterial genus was not reported yet. Similarly, it has not reported about xylanase production from N. spinosa. The bacterial strain P5B1 identified as Lysinibacillus sp. was cultivated on submerged fermentation using as substrate xylan, wheat bran, corn straw, corncob, and sugar cane bagasse. Corn straw and wheat bran show a good xylanase activity after 72 h of fermentation. A fungus identified as N. spinosa (strain P2D16) was cultivated on solid-state fermentation using as substrate source wheat bran, wheat bran plus sawdust, corn straw, corncob, cassava bran, and sugar cane bagasse. Wheat bran and corncobs show the better xylanase production after 72 h of fermentation. Both crude xylanases were characterized and a bacterial xylanase shows optimum pH for enzyme activity at 6.0, whereas a fungal xylanase has optimum pH at 5.0–5.5. They were stable in the pH range 5.0–10.0 and 5.5–8.5 for bacterial and fungal xylanase, respectively. The optimum temperatures were 55C and 60 °C for bacterial and fungal xylanase, respectively, and they were thermally stable up to 50 °C.     

Pressurized liquid extraction of active ingredients (ginsenosides) from medicinal plants using non-ionic surfactant solutions

The feasibility of employing aqueous non-ionic surfactant solutions as an alternative solvent system in pressurized liquid extraction (PLE) is demonstrated for the first time using the roots of American ginseng as model solid samples. When compared to the use of pure water or methanol, the presence of a common non-ionic surfactant (Triton X-100) in water at a concentration above its critical micelle concentration was shown to enhance the amount of pharmacologically active ingredients (ginsenosides) extracted from ginseng roots. The advantages of using aqueous non-surfactant solutions were also demonstrated by comparing extraction performances between ultrasonic-assisted extraction and PLE methods. Furthermore, the combination of PLE and cloud point extraction was shown to be a new and effective approach for the rapid sample preconcentration of herbal materials prior to analysis by high-performance liquid chromatography.     

Thermoplastic starch films with vegetable oils of Brazilian Cerrado

Starch is one of the most promising natural polymers to be abundant, cheap and biodegradable. To get thermoplastic starch (TPS) is necessary mechanical shake, high temperature and use of plasticizers. In this work, TPS films were prepared by casting from cassava starch and three different vegetable oils of Brazilian Cerrado as plasticizer: buriti, macauba and pequi. The materials were analyzed by TG, DSC and TMA. Thermal properties of oils depend on their chemical structures. Starch and vegetable oils are natural resources that can be used how alternative to producing materials that cause minor environmental impact.     

大叶榕须有效成分提取工艺研究

本文对大叶榕榕树须的黄酮类化合物有效成分进行了提取,并利用分光光度法对黄酮类化合物进行了测定。以芦丁绘制标准曲线得出回归方程为:A=12.191C(mg.m-l1)-0.0016,r=0.9996。通过溶剂筛选实验,确定乙醇较适合大叶榕须中黄酮类化合物的提取。确定了乙醇加热回流提取的最佳工艺条件为:乙醇浓度70%,提取温度70℃,料液比1∶15,提取时间2.5h。在此工艺条件下提取,大叶榕榕须总黄酮的提取率为3.71%。正交试验结果表明,影响大叶榕须总黄酮提取率的因素的主次顺序为:提取次数料液比提取时间乙醇浓度。     

Crystal engineering of pharmaceutical co-crystals from polymorphic active pharmaceutical ingredients

The carboxylic acid-primary amide supramolecular heterosynthon is exploited for the generation of pharmaceutical co-crystals that contain two active pharmaceutical ingredients that are polymorphic in their pure forms.     

Androgen receptor binding affinity of pesticide "active" formulation ingredients. QSAR evaluation by COREPA method

The COREPA approach for identifying the COmmon REactivity PAttern of biologically similar chemicals was employed to upgrade the recently derived affinity pattern for high androgen receptor (AR) binding affinity. The training set consisted of 28 steroidal and nonsteroidal ligands whose AR binding affinity was determined in competitive binding assays (in terms of pKi). The interatomic distances between nucleophilic sites and their charges providing distinct and non-overlapping integral patterns for active and inactive chemicals were assumed that it was related with the endpoint, which was under study. These stereoelectronic characteristics were used to predict pKi values of pesticide "active" formulation ingredients in an attempt to identify chemicals with potential AR binding affinity.     

Androgen receptor binding affinity of pesticide "active" formulation ingredients. QSAR evaluation by COREPA method

The COREPA approach for identifying the COmmon REactivity PAttern of biologically similar chemicals was employed to upgrade the recently derived affinity pattern for high androgen receptor (AR) binding affinity. The training set consisted of 28 steroidal and nonsteroidal ligands whose AR binding affinity was determined in competitive binding assays (in terms of p K i ). The interatomic distances between nucleophilic sites and their charges providing distinct and non-overlapping integral patterns for active and inactive chemicals were assumed that it was related with the endpoint, which was under study. These stereoelectronic characteristics were used to predict p K i values of pesticide "active" formulation ingredients in an attempt to identify chemicals with potential AR binding affinity.     

Polysulfides as biologically active ingredients of garlic

Garlic has long been considered as a natural remedy against a range of human illnesses, including various bacterial, viral and fungal infections. This kind of antibiotic activity of garlic has mostly been associated with the thiosulfinate allicin. Even so, recent studies have pointed towards a significant biological activity of trisulfides and tetrasulfides found in various Allium species, including a wide range of antibiotic properties and the ability of polysulfides to cause the death of certain cancer cells. The chemistry underlying the biological activity of these polysulfides is currently emerging. It seems to include a combination of several distinct transformations, such as oxidation reactions, superoxide radical and peroxide generation, decomposition with release of highly electrophilic S(x) species, inhibition of metalloenzymes, disturbance of metal homeostasis and membrane integrity and interference with different cellular signalling pathways. Further research in this area is required to provide a better understanding of polysulfide reactions within a biochemical context. This knowledge may ultimately form the basis for the development of 'green' antibiotics, fungicides and possibly anticancer agents with dramatically reduced side effects in humans.     

Biologically active polysaccharides from medicinal plants of the Far East

In a search for biologically active polysaccharides, we have investigated ten species of plants from six families of the flora of the Far East. By successive extractions with water and solutions of ammonium oxalate and of sodium hydroxide we have isolated polysaccharides from the roots and epigeal parts and have determined their qualitative and quantitative monosaccharide compositions. The polysaccharides obtained have been studied for immunostimulating, antitumoral, and antiviral activities.Pacific Ocean Institute of Bioorganic Chemistry, Far-Eastern Division of the Russian Academy of Sciences, Vladivostok, fax 7(4232) 31 40 50. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 197–201, March–April, 1997.     

Construction of coaxial liquid centrifugal platform for the extraction of active ingredients from natural products

In the classical natural product extraction and separation process, it is tedious and requires large amounts of reagents and time. In this study, an efficient coaxial liquid centrifugal oil-water-oil triple-liquid-phase system with a simple structure and convenient operation was successfully constructed and used to extract flavonoids from Platycladi Cacumen. The results showed that the coaxial liquid centrifugal platform constructed in this study had good stability and 6 ml was the minimum volume of the middle phase for 1000 rpm to stabilize the system. Besides, it was easy to repeat the operation: the relative standard deviations of the extraction yields of flavonoids and sugar in six parallel operations were all less than 10%. Moreover, it was only one-tenth of the time required for this method as traditional liquid-liquid extraction while reducing the use of volatile organic reagents. Finally, the new method was more selective than the traditional method for the extraction of flavonoids. Therefore, this study provides a possibility for the coaxial liquid centrifugal platform to be used in multi-liquid phase systems to achieve the simultaneous extraction of different parts of natural products by different liquid phases. It is expected to provide a reliable reference for further expansion of small-scale experimental operations to industrial production.     

Chemically modified polymeric filtration membranes for the selective elimination of active pharmaceutical ingredients from water

Poly(ether sulfone) (PES) filtration membranes were chemically modified by ultraviolet‐assisted graft polymerization radical reactions using two monomers, namely acrylic acid (AA) and N‐vinyl‐2‐pyrrolidone (NVP). The reaction kinetics was assessed by applying increasing irradiation durations keeping the monomer concentration constant, and the degree of substitution of the produced materials was monitored by attenuated total reflection‐Fourier transform infrared spectroscopy. The selective binding properties of the produced chemically modified membranes of a series of active pharmaceutical ingredients (APIs), namely 4‐acetamidophenol (APAP), ofloxacin (OFX), ciprofloxacin (CFX), tetracycline (TC), chloramphenicol (CHPH), (±)‐propranolol (PRO) and diclofenac (DF) were evaluated by means of high‐performance liquid chromatography. It was observed that native PES membranes showed specific elimination of some of the selected pharmaceuticals (i.e. PRO, OFX, CFX and DF), and this elimination was improved after chemical modification with AA (except for DF). After chemical modification by NVP, the binding properties were partially improved for several pharmaceuticals, namely TC, CHPH and PRO, and partially reduced for OFX and CFX. The selective elimination of PRO was significantly improved with both AA‐ and NVP‐modified membranes. The reported results demonstrated that the chemical modification of PES filtration membranes allowed improving significantly their API retention properties. Copyright © 2013 John Wiley & Sons, Ltd.     

Two antifungal active triterpenoid saponins from the seeds of Lathyrus plants

Two novel triterpenoid glycosides have been isolated from butanolic seeds extract of two varieties of Lathyrus plants, i.e. Lathyrus ratan and Lathyrus aphaca. Their structures were elucidated as 3-O-[β-D-glucuronopyranosyl-(1?→?4)-α-L-arabinopyranosyl-(1?→?2)-α-L-arabinopyranosyl]-olean-11,13(18)-dien-28-oic acid (1) and 3-O-{β-D-xylopyranosyl-(1 → 2)-β-D-glcopyranosyl-(1?→?4)-[β-D-glucopyranosyl-(1?→?2)]-β-D-xylopyranosyl}-2,16α-dihydroxy-4-hydroxymethyl urs-12-en-28-oic acid (2) on the basis of spectral evidences, i.e. FTIR, (1)H-NMR, (13)C-NMR, ESI-MS and FAB-MS data. The isolated saponins were tested for their antifungal activity. Compound 1 showed maximum inhibition against Colletotrichum dematium (77.8%), whereas compound 2 showed maximum inhibition against Alternaria alternata (53.9%).     

分子印迹技术在天然产物有效成分分离纯化中的应用

天然产物体系复杂,大分子和小分子、生命和非生命物质共存,多存在结构相近的异构体,且有效成分含量低,采用一般的分离方法富集难度较大。分子印迹技术是制备高选择性分离介质的有效技术手段,分子印迹聚合物(MIP)的选择性强,分离操作简单,在各种分离纯化中展现了良好的应用前景。本文对近年来分子印迹技术在天然产物活性组分(如生物碱、甾体、多元酚、黄酮等)的分离纯化中的应用进行了综述,并介绍了本课题组利用MIP从天然产物中分离纯化莽草酸等活性成分的研究进展。     

Antibacterial activity of eight Brazilian annonaceae plants

Sixteen extracts, obtained from eight Brazilian plants of Annonaceae family, were screened for their antibacterial activity: Xylopia frutescens, X. aromatica, X. amazonica, X. benthamii, Annona ambotay, A. crassiflora, A. muricata and A. cherimolia. Amongst the investigated extracts, six showed antibacterial activity against at least one of the tested organisms at the concentration of 100 microg/mL. The most active extracts were those prepared from X. frutescens, X. amazonica, and A. ambotay. A phytochemical screening showed the presence of anonaceus acetogenins in some active extracts. Eleven diterpenoids were also tested for comparison purposes. Six were natural products, previously isolated from Xylopia sp. (kaurenoic, frutoic, xylopic, 15beta-hydroxy-kaurenoic and trachylobanic acids plus kaurenol) and five were derivatives of such compounds, obtained by esterification or reduction reactions. Trachylobanic acid showed antibacterial activity against B. subtilis and S. aureus.     

Screening of acetogenin-producing plants in Brazilian flora

The acetogenins are strongly bioactive natural compounds present in the bark, roots, leaves, and seeds of manyAnnonaceae plants. They are modified fatty acids and their cytotoxicities have been determined for different biological models including the in vitro growth inhibition of several human cancer cell lines. Very low acetogenin yield (< 0.1 g%) has been found previously in native phytobiomass, and we have now investigated the nonpredatory exploitation of the seeds as acetogenin sources characterizing the seed triacylglycerols (dominant fraction; > 90% of the whole lipid extracts) as potential valuable by-products.