The drug aloes has been known since earliest times and is mentioned in the Ebers papyrus of circa 1,500 B.C. Alexander the Great is reported to have sent a commission to Socotra to investigate the aloes grown there. The chemical composition of aloes is complex, and being of plant origin, subject to variation. Both the complexity of the chemical constituents and their biological variation has resulted in a very large volume of conflicting material being published on this drug export. Since aloes is used as a purgative for both human and veterinary use, it is obviously important that the dosage and consequently the active constituents, should comply to an accurate means of standardisation. To date, despite extensive world wide research into this drug such standardisation has not been achieved. Even the methods used for the assay of the principal constituent, aloin, vary considerably in their results, and to complicate matters new chemical principles have been isolated from aloes in recent years. Consequently the purpose of this work has been to investigate the main chemical assay methods currently in use, and to determine which was the most accurate, and why discrepancies occurred in the selected assay methods. furthermore the results obtained by chemical assay have been compared with those obtained by biological assay in an attempt to correlate aloin content with purgative activity. Newly isolated compounds have been investigated biologically for the first time, and the biological assays of the resinous, glycosidal and other compounds of aloes have been performed. Intro. p.1-2.

M.Sc. (Biochemistry) / A rich diversity of medicinal plants is found in Southern Africa and approximately 80% of the population still relies on medicinal plants to fulfil its primary health care needs. Many of these medicinal plants are used to treat ailments such as burns, sores, urinary tract infections, colds, flu, rheumatism, gout, cancer, hypertension, diabetes, human immunodeficiency virus infections and acquired immunodeficiency syndrome. An example of such a plant is Hypoxis hemerocallidea (Fisch & CA Mey), formerly known as Hypoxis rooperi and popularly known as the African potato, from the Hypoxidaceae family. This plant is found across five of the South African provinces and corm extracts are reported to contain bioactive compounds that account for the plant’s medicinal and therapeutic properties. This study was conducted to investigate the anti-oesophageal cancer and antimicrobial potential of H. hemerocallidea. In cancer patients, the currently used cancer treatments such as radiotherapy and chemotherapy are ineffective in decreasing disease progression, prolonging survival, providing cure and are associated with side-effects such as cytotoxicity to normal body cells and tumour non-specificity. Therefore, current cancer research is aiming at searching for novel plant-based anticancer compounds that can be used for the development and manufacturing of cancer treatment drugs that will have less side-effects and less toxicity towards the normal human body cells, and ultimately provide cure for cancer. In addition to cancer, infectious diseases still contribute to most premature deaths worldwide and are now becoming more difficult to treat due to multidrug resistance developed by pathogens against many of the currently used antibiotics. This multidrug resistance of human pathogens to antibiotics has led to a search for new antimicrobial compounds from plants sources, for use in the production of new affordable antibiotic drugs to effectively treat infections without posing any unwanted toxicity and harm towards the human body. An oesophageal SNO cancer cell line was treated with H. hemerocallidea extracts and the effect of the extracts on the cancer cells were investigated with cell viability assays (trypan blue dye exclusion and AlamarBlue® viability assays), light microscopy and flow cytometrical analysis (forward and side scatter analysis). The plant extracts were also tested for antimicrobial activities against various microorganisms - Gram-positive and Gram-negative bacteria, yeast and fungi cultures by means of thin layer chromatographic bioautography (TLC-DB), microdilution assays and the BacTiter-GloTM assay. Antimicrobial compounds were then putatively identified and characterised using gas chromatography-mass spectrometry (GC-MS). No morphological changes were observed in the SNO cells and significant cell death did not occur following treatment with either water or ethanolic H. hemerocallidea extracts from fresh or dried corms or leaves. The ethanolic leaf extracts did not show any significant inhibition against any of the microorganisms tested in contrast to the ethanolic extracts from the corms, which showed microbial growth inhibition against Gram-positive bacteria and fungi and partial inhibition of the Gram-negative bacteria. The bioactive compounds responsible for the antibacterial and antifungal activities were identified as levoglucosan (as the major antimicrobial compound), pyrocatechol and hexahydro-3-(2-methylpropyl)-pyrrolo[1,2-α]pyrazine-1,4-dione. These results show that H. hemerocallidea plant extracts possessed no anticancer effects towards the SNO cell line. In addition, the corm extracts of H. hemerocallidea contain a levoglucosan compound, which may work synergistically with other antimicrobial compounds to exert antimicrobial properties. With more research, the antimicrobial compounds in H. hemerocallidea may hold promise for possible candidates for use in the development of antibiotic or antiseptic products (for example, topical creams and lozenges) to be used in the treatment of skin and soft tissue infections caused by bacterial and fungal infections.

The use of plants for cosmeceutical applications is becoming more important since “safer” and more “natural” skin products are gaining popularity. The effect of different drying methods and storage conditions on metabolite changes and biological activity of two species with cosmeceutical application namely Greyia flanaganii and Leucosidea sericea were investigated using 1H-NMR metabolomics. The multivariate analysis (PCA and OPLS-DA), and 1H-NMR sample spectra were used to analyse the significant differences (P<0.05) resulting from the different treatments. The effect of these treatments on anti-tyrosinase and anti-bacterial (against Staphylococcus aureus) activity of G.flanaganii and L.sericea ethanol leaf extracts respectively, was further investigated to assess the quality. Four different drying methods adopted were freeze drying, oven drying at 50°C, air drying at room temperature and sun drying in a greenhouse. The dried leaf extracts were stored in three different conditions of fridge, freezer and shade conditions and samples from each storage condition taken for analysis at three and six months of storage. The chemical constituents of the leaf extracts of both species were not affected by the drying method and the storage condition, but the concentrations of the metabolites changed. The treatments did not show a significant difference (P<0.05) on the biological activity of the extracts. However, G.flanaganii plant material harvested from the University of Pretoria exhibited a higher anti-tyrosinase activity than material harvested from Mothong heritage site. In G. flanaganii freshly freeze and oven dried extracts exhibited a higher anti-tyrosinase activity with fifty percent inhibitory (IC50) activity of 16.8±0.69 μg/ml and 15.73±0.85 μg/ml respectively than the activity of sun and air dried with IC50 values of 33.08±0.78 μg/ml and 36.86±2.01 μg/ml respectively. The metabolite concentrations and anti-tyrosinase activity dropped significantly after storage. Leucosidea sericea oven and freeze dried extracts, exhibited good anti-bacterial activity with a minimum inhibitory concentration (MIC) value of 0.25 μg/ml and 0.125 μg/ml respectively as compared to sun and air dried extracts with the same MIC value of 0.5 μg/ml. Freeze dried samples showed the best anti-bacterial activity (MIC 0.125 μg/ml) compared to other drying methods. Fridge and freezer storage conditions enhanced the activity of stored sample. / College of Agriculture and Environmental Sciences / M. Sc. (Agriculture)

Thesis (D. Tech. (Biomedical Technology)) -- Central University of Technology, Free State, 2014 / Medicinal plants are part of indigenous people‟s cultural heritage, thus since ancient times treatment of various diseases using medicinal plants has been part of human culture. The value of medicinal plants to mankind has been very well proven. It is estimated that 70% to 80% of people worldwide rely mainly on traditional health care systems, especially on herbal medicines (Stanley and Luz, 2003). In many societies the medicinal properties of plants were discovered mostly through trial and error, but use was also influenced by the belief systems of the people involved and often became entangled with religious and mythical practices (Mathias et al., 1996). Besides that, medicinal plants are proving to be rich resources of constituents that can be used in drug development and synthesis. Medicinal plants have been a source of a wide variety of biologically active compounds for many centuries and have been used extensively as crude material or as pure compounds for treating various disease conditions. Between 1% and 10% of plants out of an estimated 250 000 to 500 000 species of plants on earth are used by humans (Boris, 1996). 2 Plants used for medicinal purposes contribute significantly to the development of major medical drugs that are used today. Most common medicines have compounds extracted from plants as their primary active ingredients and many have provided blueprints for synthetic or partially synthesized drugs (Simpson and Ogorzaly, 2001). There has been a major resurgence of interest in traditionally used medicinal plants, with a number of international and local initiatives actively exploring the botanical resources of southern Africa with the intention to screen indigenous plants for pharmacologically active compounds (Gurib-Fakim et al., 2010; Rybicki et al., 2012). South Africa is considered a “hot spot” for biodiversity and more than 22 000 plant species occur within its boundaries. This represents 10% of the world‟s species, although the land surface of South Africa is less than 1% of the earth‟s surface (Coetzee et al., 1999). Plants have also been used by man for various purposes, among others as arrow and dart poisons for hunting, poisons for murder, hallucinogens used for ritualistic purposes, stimulants for endurance and hunger suppression, as well as medicine (Duke et al., 2008; Cragg and Newman, 2005). A derivative of the polyhydroxy diterpenoid ingenol isolated from the sap of Euphorbia peplus (known as “petty spurge” in England or “radium weed” in Australia), which is a potential chemotherapeutic agent for skin cancer, is currently under clinical development by Peplin Biotech for the topical treatment of certain skin cancers (Kedei et al., 2004; Ogbourne et al., 2004). Combretastatin A-4 phosphate, 3 a stilbene derivative from the South African bush willow, Combretum caffrum, acts as an anti-angiogenic agent causing vascular shutdowns in tumors (Newman et al., 2005; Holwell et al., 2002). Further reliance on plants for drug development is demonstrated by the use of galantamine hydrobromide, an alkaloid obtained from the plant Galanthus nivalis used traditionally in Turkey and Bulgaria for the treatment of Alzheimer‟s disease (Howes et al., 2003; Heinrich and Teoh, 2004). The plant chemicals used for the above-mentioned purposes are secondary metabolites, which are derived biosynthetically from plant primary metabolites (e.g. carbohydrates, amino acids and lipids). Secondary metabolites are organic compounds that are exclusively produced by plants and that are not directly involved in the normal growth, development and reproduction of a plant (Firn and Jones, 2003). Yet, they have many functions that are important for the plant‟s long-term health and appearance. Plants, being stationary, have to cope with a number of challenges, including engineering their own pollination and seed dispersal, local variation in the supply of the simple nutrients that they require to synthesize their food and the coexistence of herbivores and pathogens in their immediate environment. Plants have therefore evolved secondary biochemical pathways that allow them to synthesize a spectrum of organic molecules, often in response to specific environmental stimuli, such as herbivore-induced damage, pathogen attacks, or nutrient deprivation (Reymond et al., 2000; Hermsmeier et al., 2001). 4 The biosynthesis of secondary metabolites is derived from the fundamental processes of photosynthesis, glycolysis and the Krebs cycle to afford biosynthetic intermediates which, ultimately, result in the formation of secondary metabolites also known as natural products (Dewick, 2002). It is hypothesized that secondary metabolism utilizes amino acids and the acetate and shikimate pathways to produce “shunt metabolites” (intermediates) that have adopted an alternate biosynthetic route, leading to the biosynthesis of secondary metabolites (Sarker et al., 2006). Modifications in the biosynthetic pathways that produce secondary metabolites are probably due to natural causes (e.g. viruses or environmental changes) or unnatural causes (e.g. chemical or radiation processes) in an effort to adapt or provide longevity for the plant (Sarker et al., 2006). Plants‟ secondary metabolites can be classified into several groups according to their chemical classes, such alkaloids, terpenoids and phenolics (Harbone, 1984; Wink, 2003).

A dissertation submitted to the Faculty of Science, University of the Witwatersrand Johannesburg for the degree of Master of Science. Johannesburg, 1992. / Acidified rain is thought to have the potential to affect the ability of plants to acquire nutrients. The effects of artificially acidified rain on calcium (Ca) and magnesium (Mg) uptake by Pinus patula were investigated in terms of changes in the Ca and Mg-levels in the soil and changes in root growth and mycorrhizal coloniZation that might result from exposure to acidified precipitation. The uptake of these ions was also investigated in order to determine the possible effects of acid rain on the uptake process [Abbreviated Abstract. Open document to view full version] / AC2017

University of Macau / Institute of Chinese Medical Sciences

Orientador: André Gonzaga dos Santos / Banca: Fábio Ferreita Perazzo / Banca: Gustavo Henrique Bianco de Souza / Banca: Taís Maria Bauab / Banca: Alexandra Ivo de Medeiros / Resumo: O objetivo geral deste trabalho foi realizar um estudo químico-farmacológico do extrato etanólico de folhas de Casearia sylvestris Swartz (EEtCs), frações obtidas por extração em fase sólida (EFS1: apolar; EFS2: rica em diterpenos clerodânicos; EFS3: polar) e padrões de diterpenos clerodânicos (DC). Os objetivos da parte química foram caracterizar os padrões de DC por espectrometria de massas (full scan e fragmentação) com fonte de ionização por spray de elétrons (ESI-MS e MSn) e identificar DC no EEtCs e na EFS2 por ESI-MS, ESI-MSn e por cromatografia em camada delgada de alta eficiência com detecção por imagem química formada por espectrometria de massas com fonte de dessorção por spray de elétrons (HPTLC-DESI-MS-IMAGING). A parte farmacológica consistiu na investigação da atividade anti-inflamatória e gastroprotetora do EEtCs, frações (EFS1-3) e padrões de DC. A atividade anti-inflamatória foi avaliada por meio de ensaios em ratos, pleurisia induzida pela carragenina e edema de pata induzido por uma fosfolipase A2 de veneno de Bothrops jararacussu (BthTX-II), e os seguintes ensaios in vitro: atividade enzimática das ciclo-oxigenases 1 e 2 (COX-1 e COX-2) e produção de óxido nítrico (NO) e prostaglandina E2 (PGE2) por macrófagos estimulados por lipopolissacarídeo. A atividade gastroprotetora foi avaliada em modelo de lesões gástricas induzidas por indometacina em ratos e ensaio in vitro de atividade anti-Helicobacter pylori. Os resultados levaram às conclusões a seguir. A caracterização dos padrões de DC por espectrometria de massas permitiu estabelecer o padrão de fragmentação dos DC com anel diacetálico do tipo das casearinas, o qual representa uma importante fonte de informação para desreplicação em estudos metabolômicos de extratos vegetais... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this study was to carry out a chemical-pharmacological study of the ethanol extract from leaves of Casearia sylvestris Swartz (EtECs), fractions obtained by solid phase extraction (SPE1: nonpolar; SPE2: rich in clerodane diterpenes; SPE 3: polar) and standards of clerodane diterpenes (CD). The objectives of the chemical step was to characterize standards of CD by mass spectrometry (full scan and fragmentation) using electrospray ionization (ESI-MS and MSn) and to identify CD in EtECs and SPE2 by ESI-MS, ESI-MSn and high performance thin layer chromatography/desorption electrospray ionization mass spectrometry imaging (HPTLC-DESI-MS-IMAGING). The pharmacological study consisted in investigation of anti-inflammatory and gastroprotective activities of EtECs, fractions (SPE1-3) and CD standards. The anti-inflammatory activity was assessed in rats through pleurisy induced by carrageenan and paw edema induced by phospholipase A2 from Bothrops jararacussu venom (BthTX-II), and the following in vitro assays: enzymatic activity of cyclooxygenases 1 and 2 (COX-1 and COX-2) and macrophage stimulation by lipopolysaccharide to investigate the production of nitric oxide (NO) and prostaglandin E2 (PGE2). The gastroprotective activity was assessed in a model of indomethacin-induced gastric lesions in rats and in vitro assay of anti-Helicobacter pylori activity. The results led to the following conclusions. The characterization of the standards of CD by mass spectrometry demonstrated that it was possible to establish the fragmentation pattern of CD with diacetalic ring like casearins, which is an important source of information for dereplication in metabolomics studies of plant extracts... (Complete abstract click electronic access below) / Doutor

As sessile organisms, plants evolved a plethora of defenses against their attackers. Given the role of plants as a primary food source for many organisms, plant defense has important implications for community ecology. Surprisingly, despite the potential to alter entire food webs and communities, the factors determining plant investment in defense are not well-understood, and are even less understood considering the numerous symbiotic interactions in the same plant. Legume-rhizobia symbioses engineer ecosystems by fixing nitrogen from the atmosphere in trade for plant photosynthates, yet connecting symbiotic resource exchange to food web interactions has yet to be established. Here I test how rhizobia influence plant defense and tritrophic interactions in lima bean (Fabaceae - Phaseolus lunatus L.): a model plant in chemical ecology research characterized by a broad range of different defenses. Examining suites of traits among lima bean genotypes, highly cyanogenic cultivars and wild type plants (high cyanotypes) produce more hook-shaped trichomes, as a putative combined approach of chemical and mechanical defenses, forming defense syndromes to protect against multiple feeding guilds (Chapter 2). Testing costs that may have contributed to forming tradeoffs among strategies, high cyanotypes show reduced fitness under plant-plant competition relative to low cyanotypes, but when challenged with herbivory, high cyanotypes fitness reductions are no longer evident (Chapter 3). Young leaves, not reproductive organs, are the most cyanogenic lima bean organ, and removal quantitatively decreases fitness, supporting assumptions that the most valuable tissues will be most highly defended (Chapter 4). Testing the degree to which nitrogen-fixing rhizobia contribute to cyanogenesis, high cyanotypes form more nodules than low cyanotypes. Quantitative relationships between nodule number and plant traits highlight the role symbiotic investment plays a role in plant defense and nutritive phenotype, while simultaneously, genotypically-determined levels of defense shape plant investment in symbiosis (Chapter 5). Interestingly, traits that trade off by cyanotype (i.e. high cyanogenesis but low indirect defense) reflect the patterns in plants with nitrogen-fixing rhizobia. Rhizobia-inoculated lima beans show reduced indirect defenses, recruiting fewer parasitoid wasps (Chapter 6) and predatory ants (Chapter 7). Examining plant-ant attraction in greater detail, ants prefer headspace regions above EFN droplets, corresponding with species-specific differences in suites of volatiles, indicating EFN, like floral nectar, can be scented to manipulate insect behavior (Chapter 8). Overall, understanding when investing in traits to recruit predators is more effective than investing in defensive chemistry, and how particular ecological contexts, such as symbioses can influence the outcome of defense allocation strategies remains a fascinating area of research. Determining the mechanisms underlying why rhizobia and other belowground microbial symbionts influence their host plants' above ground interactions, whether plants traits affected by symbiotic microbes are simply a function of the costs and benefits from resource exchange, or whether symbionts can influence the success of primarily direct versus indirectly defended plants is an important question for understanding complex trophic systems and connecting to agricultural implications for more effective biological pest control.

This study was undertaken to redress the scant knowledge regarding the chemistry and mode of action of pregnancy-related traditional medicines, or isihlambezo (Zulu), which are used by 60 to 80% of women in South Africa. The three selected plants are among the six most frequently cited species from the approximately 90 used by traditional healers. The purpose of the study was to identify components which could cause uterine contractions, those with nutritional value for the foetus and mother, and those with any toxic effects. Plant root extracts were purified via silica gel column chromatography and bioassays were carried out on the fractions, using isolated rat uterine tissue. Purified compounds were identified via spectral techniques, and some were characterised by comparison to authentic standards using HPLC, and others by matching their GC-MS spectra to library standards. Thirty-eight compounds were identified in total, the majority of these being novel to the species concerned. Those isolated from Combretum kraussii were 1 sitosterol, 2 combretastatin, 3 3',4-tri-O-methylellagic acid, 4 combretastatin B-1, 5 combretastatin A-1, 6 3,3'-di-O-ellagic acid lactone, 7a ellagic acid lactone, 7b ellagic acid, 8 and 9 a mixture of combretastatin B-1 and A-1 glucosides, 10 and 11 partly characterised glucosides of ellagic acid. Those isolated from Gunnera perpensa were 12 3',4-tri-methylellagic acid, 13 ellagic acid lactone, 14 1,1'-biphenyl-4,4'-diacetic acid, 15 p-hydroxybenzaldehyde, 16 Z-methyl lespedezate, 17 and 18 partly characterized higher glucosides of Z-methyllespedezate. Those isolated rom Rhoicissus tridentata were 19 (-)-epigallocatechin, 20 (+)-gallocatechin, 21 procyanidin B3, 22 procyanidin B4, 23 (+)-catechin hydrate, 24 (+)-mollisacacidin, 25 (+)-epicatechin, 26 fisetinidol-(4a-8) catechin, 27 (-)-fisetinidol, 28 fisetinidol-(4b-8)catechin, 29 gallic acid, 30 epicatechin-3-0-gallate, 31 partly characterized hydrogel of glucose, 32 sitosterol, 33 sitosterolin, 34 y-sitosterol, 35 oleanolic acid, 36 lupen-3-one, 37 20-epi-y-taraxastananol and 38 triacontanol. The compounds with the greatest in vitro uteroactivity were predominantly proanthocyanidins or phenolic glucosides. It is proposed that effects of phenolic glucosides could be due to the interaction of the sugar moiety as well as the phenolic moiety with the receptor site in muscle tissue. The corresponding phenolic aglycones isolated were only moderately uterotonic, or unreactive by comparison. Non-polar compounds such as sitosterol and sitosterolin showed minimal enhancement of the uterine response at low concentrations, and inhibition at higher concentrations. Aqueous root extracts of the plants were all found to be non-toxic according to cell-viability tests using monkey vero cells and human fibroblasts. Extracts are therefore considered safe for human consumption, although it is recommended that Rhoicissus tridentata be used with caution because it showed the lowest cell viability of the three species, and uterine hyperstimulation has been attributed to this species, as well as CNS depression and respiratory arrest. Ions which could be nutritionally beneficial in pregnancy, calcium, iron, and phospate, were present in low in aqueous extracts. Levels of calcium and potassium ions were considered to be too low to directly stimulate uterine muscle. Proanthocyanidins, combretastatins, ellagic acid derivatives and phytosterols, with health-promoting properties, were also identified. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2004.

Thesis (PhD) -- University of Western Sydney, Nepean, 1998. / Bibliography : p. 164-171.