Добірка наукової літератури з теми "Smilax glyciphylla"

Aboriginal people of Australia possess a rich knowledge on the use of medicinal plants for the treatment of sores, wounds, and skin infections, ailments which impose a high global disease burden and require effective treatments. The antibacterial and antioxidant activities and phytochemical contents of extracts, obtained from eight medicinal plants used by Aboriginal people of New South Wales, Australia, for the treatment of skin related ailments, were assessed to add value to and provide an evidence-base for their traditional uses. Extracts ofAcacia implexa,Acacia falcata,Cassytha glabella,Eucalyptus haemastoma,Smilax glyciphylla,Sterculia quadrifida, andSyncarpia glomuliferawere evaluated. All extracts except that ofS. quadrifidashowed activity against sensitive and multidrug resistant strains ofStaphylococcus aureuswith minimum inhibitory concentration values ranging from 7.81 to 1000 μg/mL. The sap ofE. haemastomaand bark ofA. implexapossessed high total phenolic contents (TPC) and strong DPPH radical scavenging abilities. A positive correlation was observed between TPC and free radical scavenging ability. GC-MS analysis of then-hexane extract ofS. glomuliferaidentified known antimicrobial compounds. Together, these results support the traditional uses of the examined plants for the treatment of skin related ailments and infections by Aboriginal people of New South Wales, Australia.

Novel species of fungi described in this study include those from various countries as follows: Argentina, Colletotrichum araujiae on leaves, stems and fruits of Araujia hortorum. Australia, Agaricus pateritonsus on soil, Curvularia fraserae on dying leaf of Bothriochloa insculpta, Curvularia millisiae from yellowing leaf tips of Cyperus aromaticus, Marasmius brunneolorobustus on well-rotted wood, Nigrospora cooperae from necrotic leaf of Heteropogon contortus, Penicillium tealii from the body of a dead spider, Pseudocercospora robertsiorum from leaf spots of Senna tora, Talaromyces atkinsoniae from gills of Marasmius crinis-equi and Zasmidium pearceae from leaf spots of Smilax glyciphylla. Brazil, Preussia bezerrensis from air. Chile, Paraconiothyrium kelleni from the rhizosphere of Fragaria chiloensis subsp. chiloensis f. chiloensis. Finland, Inocybe udicola on soil in mixed forest with Betula pendula, Populus tremula, Picea abies and Alnus incana. France, Myrmecridium normannianum on dead culm of unidentified Poaceae. Germany, Vexillomyces fraxinicola from symptomless stem wood of Fraxinus excelsior. India, Diaporthe limoniae on infected fruit of Limonia acidissima, Didymella naikii on leaves of Cajanus cajan, and Fulvifomes mangroviensis on basal trunk of Aegiceras corniculatum. Indonesia, Penicillium ezekielii from Zea mays kernels. Namibia, Neocamarosporium calicoremae and Neocladosporium calicoremae on stems of Calicorema capitata, and Pleiochaeta adenolobi on symptomatic leaves of Adenolobus pechuelii. Netherlands, Chalara pteridii on stems of Pteridium aquilinum, Neomackenziella juncicola (incl. Neomackenziella gen. nov.) and Sporidesmiella junci from dead culms of Juncus effusus. Pakistan, Inocybe longistipitata on soil in a Quercus forest. Poland, Phytophthora viadrina from rhizosphere soil of Quercus robur, and Septoria krystynae on leaf spots of Viscum album. Portugal (Azores), Acrogenospora stellata on dead wood or bark. South Africa, Phyllactinia greyiae on leaves of Greyia sutherlandii and Punctelia anae on bark of Vachellia karroo. Spain, Anteaglonium lusitanicum on decaying wood of Prunus lusitanica subsp. lusitanica, Hawksworthiomyces riparius from fluvial sediments, Lophiostoma carabassense endophytic in roots of Limbarda crithmoides, and Tuber mohedanoi from calcareus soils. Spain (Canary Islands), Mycena laurisilvae on stumps and woody debris. Sweden, Elaphomyces geminus from soil under Quercus robur. Thailand, Lactifluus chiangraiensis on soil under Pinus merkusii, Lactifluus nakhonphanomensis and Xerocomus sisongkhramensis on soil under Dipterocarpus trees. Ukraine, Valsonectria robiniae on dead twigs of Robinia hispida. USA, Spiralomyces americanus (incl. Spiralomyces gen. nov.) from office air. Morphological and culture characteristics are supported by DNA barcodes.

The work within this thesis is positioned in the field of natural product (NP) chemistry and covers three main integrated studies along with some additional explorations. These studies not only included the isolation and characterisation of NP but also involved total syntheses of various NP and related derivatives and detailed mechanistic studies into potential routes of formation in nature. Given my naturally emerging zest for natural products, I have begun this thesis with a detailed discussion of the numerous syntheses of Taxol. This exemplar highlights not only why the field of natural products is so important, but also highlights the ever growing significance of total and semi-syntheses. The first major study investigated the phenolic profile and antioxidant activity of the leaves of the Australian native plant Smilax glyciphylla. Along with the sweet principle glycyphyllin A, seven phenolic compounds including two new dihydrochalcone rhamnosides, glycyphyllin B and C, and five known flavonoids were isolated from the ethanolic extract of the leaves of Smilax glyciphylla for the first time. The structures of these compounds were characterised by spectroscopic methods including UV, HRMS, 1D and 2D NMR. In vitro antioxidant capacity tests employing the FRAP and DPPH assays indicated that three of the isolated compounds exhibited potent antioxidant activity and are the key phenolics responsible for the high antioxidant activity of the leaf extract of S. glyciphylla. The second major study focused on the synthesis of guaiane type sesquiterpenoids via the diastereoselective epoxidation of guaiol and realized by manipulating the types of remote protecting groups on the isopropanoyl side chain, choice of solvent and epoxidising reagent. This stragety allowed for a concise stereoselective synthesis of a range of guaiane-type sesquiterpenoids including the natural products guaia-4(5)-en-11-ol, guaia-5(6)-en-11-ol, and aciphyllene and epimers of the recently isolated natural products, 1-epi-guaia-4(5)-en-11-ol, 1-epi-aciphyllene and 1-epi-melicodenone C and E in up to 31% yield within 11 steps. The third study explored the autoxidation of α-guaiene and the mechanisms involved. Over a dozen sesquiterpenoids including natural rotundone, corymbolone and the C7 epimers of natural chabrolidione A and several unstable hydroperoxide intermediates were isolated from the autoxidation products of α-guaiene. Their structures were elucidated on the basis of spectroscopic data along with the synthesis of authentic compounds. Detailed mechanistic studies have allowed many of the mechanisms involved in the formation of these downstream oxidation products to be elucidated. Together with the above main studies, several deuterium labelled precursors including d₇-α- guaiene, d₅-(2R/2S)-rotundols, d₅-α-bulnesone, d₇-α-bulnesene and d₅-2R-bulnesol were synthesised and used as internal standards to develop a robust analytical method (SIDA) to monitor the transformation of certain precursors to the sesquiterpneoid fragrances rotundone and 2R-bulnesol. A total of five publications support my research works herein and are included as the main research chapters of this thesis.
Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2014