• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 14
  • 9
  • 1
  • Tagged with
  • 25
  • 25
  • 14
  • 14
  • 6
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Studies on the medicinal plants of Puerto Rico

Asenjo, Conrado F., January 1940 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1940. / Typescript. Includes abstract and vita. Includes bibliographical references (leaves 124-130).
2

Synthesis of magnetic sorbents modifie with moringa oleifera extracts for the removals of environmental orgamnic pollutants

Kgatitsoe, Maureen Maletsatsi January 2018 (has links)
A Masters dissertation submitted to the Faculty of Science, University of the Witwatersrand in fulfillment of the requirements of the degree of Master of Science, January 2018 / Modern developments on nanoparticles (NPs) has led to new innovation in nanoparticles that can be used for the treatment of polluted water. Magnetic NPs are of great interest because of their unique properties and promising applications. Their stability is essential to prevent them from agglomeration, hence, modification with a specific coating layer can assist in the selectivity function and stability of the magnetic NPs. In this work, a magnetic organic nano-adsorbent was synthesized and investigated for the application in the extraction of nitroaromatic explosive compounds from aqueous solutions. The approach was to find a possible synergy between the adsorptive properties of Moringa oleifera and the high surface area of the NPs. The magnetic NPs were utilized for their ferromagnetic properties which assist in the extraction procedure. M. oleifera was used as a natural coating agent to functionalize the magnetic NPs and also to provide stability. There are numerous chemical procedures to synthesize magnetite and one of the simplest and convenient procedures, co-precipitation, was used in this study. Magnetite can be easily oxidized under ambient conditions, hence, in order to prevent oxidation, M. oleifera extracts were used as a coating agent. The synthesized uncoated magnetite NPs and M. oleifera coated magnetite NPs were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR), Brunauer, Emmett and Teller (BET) and thermogravimetric analysis (TGA). The M. oleifera leaf extract was obtained using pressurized hot water extraction (PHWE) at 80°C and the seed extract was purchased as a pure oil. Both the M. oleifera leaf and seed extracts were characterized by FTIR and gas chromatography–mass spectrometry (GC-MS) for possible organic compounds assisting in the stability of the magnetite. From the BET results of the coated magnetic NPs at different times, it was observed that with increasing coating time, the surface area decreased while the pore size increased. To optimize the extraction of nitroaromatic explosive compounds (NAECs), the parameters that were investigated were sample pH, contact time, mass of adsorbent and initial concentration. The optimum value for pH of the sample was found at pH8 and for the contact time an optimum of 120 min was found. The mass of M. oleifera coated magnetic NPs for the maximum removal of explosives were found to be 100 mg. The adsorption capacity of the NAECs was obtained in the range of 0.45 and 0.76 mg g-1 at optimum conditions. During kinetic studies it was observed that the pseudo second order model explained the extent of the adsorption mechanism. It was observed that the Langmuir model was favourable as compared to the Freundlich model. The order of selectivity for the NAECs studied was observed as follows: 2-NT ≈ 3-NT > 4NT > NB > 2,6-DNT > 1,3-DNB. The limit of detection (LOD) found was 0.37 – 4.47 and 0.45 – 5.66 ng.mL-1 for extraction using magnetic NPs coated with M. oleifera leaf and seed extract, respectively. The percentage recovery for the extraction of NAECs at optimum conditions was obtained in the range 14 – 46%. / XL2018
3

Phytochemistry of Aptosimum procumbens and Garuleum bipinnatum.

Timmerman, Elizabeth 19 May 2008 (has links)
Plants are an invaluable source of medicinal compounds and their use for healing is rooted in ancient times. Aptosimum procumbens (Scrophulariaceae) and Garuleum bipinnatum (Asteraceae) are two indigenous South African plants that have been used as traditional remedies. Phytochemical investigations were performed with the aim of isolating and identifying compounds that may be responsible for the recorded medicinal properties of these plants. Various chromatographic techniques were utilized for the separation of the plant extract constituents. Several terpenoid compounds were isolated from both plants and the flavanone was isolated from A. procumbens. Nuclear magnetic resonance spectroscopy including 1H NMR, 13C NMR, COSY, DEPT, HMQC, HSCQ, HMBC and NOESY experiments were performed to allow for structure determination, the results of which will be discussed. The iridoid glycosides angeloside, shanzhiside methyl ester, barlerin, a new compound foliamethoylshanzhiside methyl ester and the flavanone pinocembrin neohesperidoside were identified as constituents of A. procumbens. Fractionation of the G. bipinnatum extract afforded several sandaracopimar-15-ene diterpenoid derivatives, namely sandaracopimar-15-ene-8ƒÒ-ol, sandaracopimar-15-ene-8ƒÒ,11ƒÑ-diol, 12-O-acetylsandaracopimar-15-ene-8ƒÒ,11ƒÑ,12ƒÒƒn-triol, 11-O-acetylsandara-copimar-15-ene-8ƒÒ,11ƒÑ,12ƒÒƒn-triol, 11-O- feruoylsandaracopimar-15-ene-8ƒÒ,11ƒÑƒz12ƒÒ-triol and 11-O-p-coumaroylsandaracopimar-15-ene-8,11ƒÑ,12ƒÒ-triol. Diterpenoids are known to possess antimicrobial properties enabling them to fight off various infections and monoterpenoid iridoid glycosides generally have anti-inflammatory properties that make them wound-healing agents. Flavonoids are a diverse group of compounds with enormous structural variations and have a wide range of medicinal properties. A general review on the structural classification, biosynthesis and biological activity of these secondary metabolites is given in this dissertation. Iridoids are commonly found in plants belonging to the Scrophulariaceae family and shanzhiside methyl ester has also been isolated from A. indivisum, a related Aptosimum species. Many plants from the Scrophulariaceae family have been used as traditional medicine to treat wounds. The crude extract of the plant tested positive for antitumor activity against three cell lines, namely melanoma, breast and renal. G. bippinatum belongs to one of the largest plant families, Asteraceae and the crude extract exhibited antimicrobial activity against several microorganisms. / Prof. F.R. van Heerden
4

In vitro 5-lipoxygenase and anti-oxidant activities of South African medicinal plants commonly used topically for skin diseases

Frum, Yakov 14 November 2006 (has links)
Faculty of Health Sciences School of Pharmacology 9410866v kermifrum@yahoo.com / ABSTRACT Thirty plant species traditionally used to treat skin pathologies were chosen from the readily available ethnobotanical literature. Four plants (aqueous or methanol extracts) displayed promising 5-lipoxygenase inhibitory activity with IC50 values below 61 ppm. These included Aloe greatheadii, Melianthus comosus, Pentanisia prunelloides and Warburgia solutaris. Essential oils generally displayed superior 5- lipoxygenase inhibitory activity with IC50 values between 22 and 75 ppm. These included the essential oils of Ballota africana, Helichrysum odoratissimum, Heteropyxis natalensis and Lippia javanica. A large proportion of the plants exhibited dose-dependent DPPH anti-oxidant activity with IC50 values between 5 and 94 ppm for the most active. These included Halleria lucida, Croton sylvaticus, Melianthus comosus, Lippia javanica and Pentanisia prunelloides. Aqueous extracts of Melianthus comosus exhibited the most potent anti-inflammatory and anti-oxidant activity. The methanol extract of the leaves of Halleria lucida was subjected to activity guided fractionation and two anti-oxidant molecules were isolated, namely luteolin-5-Oglucoside and verbascoside (acteoside). Isobologram construction resulted in a concentration-dependent additive and antagonistic interaction being recognised between the two isolated compounds. Warburgia salutaris displayed promising 5-lipoxygenase inhibitory activity. Two isolated compounds, mukadiaal and warburganal were found to partially contribute to the anti-inflammatory activity of the plant. The essential oils of Helichrysum odoratissimum, Heteropyxis natalensis and Lippia javanica were subjected to gas chromatography and major compounds contributing to possible anti-inflammatory effects identified. These included β-caryophyllene, 1,8-cineole, limonene and α- humulene. Enantiomers and racemic mixtures of limonene displayed significantly different 5-lipoxygenase inhibitory activity suggesting stereoselectivity of the enzyme-catalysed reaction. The monoterpene 1,8-cineole appeared to cause partial potentiation of the anti-inflammatory activity displayed by limonene. These results provide some in vitro scientific rationale for their traditional use as dermatological agents.
5

Isolation and characterization of bio-active compounds from euphorbia inaequilatera and dicerocaryum senecioides

Ngobeni, Alister January 2012 (has links)
Thesis (M.Sc. (Biochemistry)) --University of Limpopo, 2013 / This study was carried out to investigate antioxidant and antibacterial properties of 9 indigenous medicinal plants, viz., Euclea undulata (mogweregwere), Momordica balsamia (mogapu badimo), sefapa badimo, Senecio asperulus (makgonatšohle), Stiburus alopecuroides (mošalašuping), serolana, Euphorbia inaequilatera (kgama-maswana), mokgagapitsi and Clerodendrum glabrum (mohlokohloko) and to further isolate compounds that relate to these properties. Four extracting solvents with varying polarities viz. n-hexane, dichloromethane, acetone and methanol were used to extract the bioactive compounds from the ground powdered plant materials. The TLC plates, developed in three solvent systems viz., benzene, ethanol and ammonia (BEA, 18:10:0.2, v/v/v); ethyl acetate, methanol and water (EMW, 10:1.35:1, v/v/v) and chloroform, ethyl acetate and formic acid (CEF, 10:8:2, v/v/v), were visualised using DPPH, vanillin-sulphuric acid, visible light at 366 nm, UV light at 254 nm and bioautography for the presence of potential antioxidant and antibacterial compounds. The results of the screening process showed that only four plants possessed antioxidant compound(s) while six plants had antibacterial activity against Staphylococcus aureus. Euclea undulata “MKK” was observed to possess both antibacterial and antioxidant active compounds. Two antioxidant active compounds were isolated from two plants, viz., Euphorbia inaequilatera and Dicerocaryum senecioides. Solvent-solvent extraction, column chromatography and preparative TLC were used to further isolate and characterise target compounds. The antioxidant active compounds were found to separate well under EMW, an indication that the compounds are polar and intermediate-polar. The NMR spectra of the compound isolated from the D. senecioides revealed that the compound is a stilbenoid. For the first time, we report that the anti-inflammatory, antioxidant and antiproliferation properties of the D. senecioides reported by other studies performed in this laboratory could be due to this isolated stilbenoid compound. However, further studies are still necessary to confirm this assertion.
6

Avaliação dos principais metabólicos secundários por espectrometria de massas e atividade hipoglicêmica de Salacia impressifolia Miers A. C. Smith

Laikowski, Manuela Merlin 27 February 2015 (has links)
A utilização de plantas na cura dos mais diversos males é tradicionalmente conhecida e utilizada há centenas de anos pela humanidade. As células vegetais produzem uma grande variedade de compostos químicos entre o metabolismo primário e secundário. Os produtos do metabolismo secundário são de especial interesse, pois são responsáveis por diversas ações biológicas. Informações etnobotânicas indicam que mais de 800 plantas são usadas como remédios tradicionais para o tratamento da diabetes. Muitas espécies pertencentes ao gênero Salacia têm sido descritas com atividade antidiabética, entre elas Salacia impressifolia. É uma espécie pertencente à família Celastraceae, conhecida popularmente no Brasil como miraruíra. Este trabalho visou desvendar a composição química desta espécie, utilizando para isso extratos obtidos a partir da casca e do caule. Em seguida, realizou-se análise química dos extratos por espectrometria de massas de alta resolução (EMAR). Nestes foram identificados 32 compostos, os quais haviam sido previamente descritos na literatura para o mesmo gênero. Entre eles destacam-se o kotalanol, salacinol e o mangiferina, com ação hipoglicemiante previamente descrita por outros autores. Para análise in vivo do potencial hipoglicemiante, realizou-se ensaio com o extrato hidroalcoólico do caule da planta em ratos com diabetes induzida por estreptozotocina. O extrato apresentou ação semelhante ao fármaco controle glibenclamida. Também foi avaliado o perfil lipídico (triglicerídeos, colesterol total e HDL) e as enzimas hepáticas TGO e TGP, onde pode-se observar aumento de HDL. / Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2015-05-06T18:00:22Z No. of bitstreams: 1 Dissertacao Manuela Merlin Laikowski.pdf: 192460 bytes, checksum: 1080985338e2e2e103da02a2651657ed (MD5) / Made available in DSpace on 2015-05-06T18:00:22Z (GMT). No. of bitstreams: 1 Dissertacao Manuela Merlin Laikowski.pdf: 192460 bytes, checksum: 1080985338e2e2e103da02a2651657ed (MD5) / The use of plants in various ailments healing is traditionally known and used for centuries by mankind. Plant cells produce a large variety of chemical compounds between the primary and secondary metabolism. The secondary metabolism products are of special interest, as they are responsible for several biological activities. Ethnobotanic information indicates that more than 800 plants are used as traditional remedies in the treatment of diabetes. Many species of Salacia genus have been described with antidiabetic activity, including Salacia impressifolia. This specie belongs to Celastraceae family, popularly known as miraruíra in Brazil. This work aimed to develop the chemical composition of this specie through stem and stem bark extracts. Chemical analysis of the extracts was carried out by high resolution mass spectrometry (HRMS). In these extracts, 32 compounds were identified, previously described for the same genus. Among them, were identified kotalanol, salacinol and mangiferina, with hypoglycemic action previously described by others authors. For in vivo analysis of hypoglycemic activity, it was performed the hydroalcoholic stem extract in streptozotocin induced diabetics rats. The extract presented similar action to control drug glibenclamide. It was also assessed the lipid profile (triglycerides, total cholesterol and HDL) and liver enzymes AST and ALT, and it was observed an increase in HDL level.
7

Estudo bioguiado da Própolis Vermelha Brasileira visando à atividade antibacteriana

Rufatto, Luciane Corbellini 20 December 2016 (has links)
Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2017-04-07T20:15:57Z No. of bitstreams: 1 Tese Luciane Corbellini Rufatto.pdf: 180334 bytes, checksum: 9a4a5f24a3a8203c8215fa238ba3aa59 (MD5) / Made available in DSpace on 2017-04-07T20:15:57Z (GMT). No. of bitstreams: 1 Tese Luciane Corbellini Rufatto.pdf: 180334 bytes, checksum: 9a4a5f24a3a8203c8215fa238ba3aa59 (MD5) Previous issue date: 2017-04-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES.
8

Avaliação dos principais metabólicos secundários por espectrometria de massas e atividade hipoglicêmica de Salacia impressifolia Miers A. C. Smith

Laikowski, Manuela Merlin 27 February 2015 (has links)
A utilização de plantas na cura dos mais diversos males é tradicionalmente conhecida e utilizada há centenas de anos pela humanidade. As células vegetais produzem uma grande variedade de compostos químicos entre o metabolismo primário e secundário. Os produtos do metabolismo secundário são de especial interesse, pois são responsáveis por diversas ações biológicas. Informações etnobotânicas indicam que mais de 800 plantas são usadas como remédios tradicionais para o tratamento da diabetes. Muitas espécies pertencentes ao gênero Salacia têm sido descritas com atividade antidiabética, entre elas Salacia impressifolia. É uma espécie pertencente à família Celastraceae, conhecida popularmente no Brasil como miraruíra. Este trabalho visou desvendar a composição química desta espécie, utilizando para isso extratos obtidos a partir da casca e do caule. Em seguida, realizou-se análise química dos extratos por espectrometria de massas de alta resolução (EMAR). Nestes foram identificados 32 compostos, os quais haviam sido previamente descritos na literatura para o mesmo gênero. Entre eles destacam-se o kotalanol, salacinol e o mangiferina, com ação hipoglicemiante previamente descrita por outros autores. Para análise in vivo do potencial hipoglicemiante, realizou-se ensaio com o extrato hidroalcoólico do caule da planta em ratos com diabetes induzida por estreptozotocina. O extrato apresentou ação semelhante ao fármaco controle glibenclamida. Também foi avaliado o perfil lipídico (triglicerídeos, colesterol total e HDL) e as enzimas hepáticas TGO e TGP, onde pode-se observar aumento de HDL. / The use of plants in various ailments healing is traditionally known and used for centuries by mankind. Plant cells produce a large variety of chemical compounds between the primary and secondary metabolism. The secondary metabolism products are of special interest, as they are responsible for several biological activities. Ethnobotanic information indicates that more than 800 plants are used as traditional remedies in the treatment of diabetes. Many species of Salacia genus have been described with antidiabetic activity, including Salacia impressifolia. This specie belongs to Celastraceae family, popularly known as miraruíra in Brazil. This work aimed to develop the chemical composition of this specie through stem and stem bark extracts. Chemical analysis of the extracts was carried out by high resolution mass spectrometry (HRMS). In these extracts, 32 compounds were identified, previously described for the same genus. Among them, were identified kotalanol, salacinol and mangiferina, with hypoglycemic action previously described by others authors. For in vivo analysis of hypoglycemic activity, it was performed the hydroalcoholic stem extract in streptozotocin induced diabetics rats. The extract presented similar action to control drug glibenclamide. It was also assessed the lipid profile (triglycerides, total cholesterol and HDL) and liver enzymes AST and ALT, and it was observed an increase in HDL level.
9

Estudo bioguiado da Própolis Vermelha Brasileira visando à atividade antibacteriana

Rufatto, Luciane Corbellini 20 December 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES.
10

Secondary metabolites of the uromycladium tepperianum macalpine epiphytic fungus

Correia, Kelly Luana Viegas January 2021 (has links)
>Magister Scientiae - MSc / Research on natural products and medicinal plants has been conducted more with each passing year due to the great interest in isolating bioactive compounds and secondary metabolites from natural products such as plants, fungi, and many other naturally occurring products. To our knowledge, the Uromycladium tepperianum MacAlpine fungus has not been studied in depth before thus, its organic characterization was unknown, but related species have been studied, and these have shown compounds that may be used as medicine and as health benefits. Crude and macerated extracts of the Uromycladium tepperianum fungus have been fractionized using various chromatographic techniques such as solvent-solvent extraction followed by dry column chromatography to achieve the required separations. Thirty-nine compounds have been isolated from the hexane(n-hex) extract, Ethylacetate (EtOAc) extract, and n-butanol (BuOH) extract, and they belong to the following groups, steroids, terpenoids, amino-acids, flavonoids, alkaloids, phenolics, fatty-acids, flavones, and others.

Page generated in 0.0732 seconds