The reproductive systems of angiosperms are quite diverse. In the flowers of Meliaceae (Sapindales) we found a wide diversity of these systems, including reports of monoecious, dioecious and polygamous plants. However, the sexual dimorphism of flowers in the family is very subtle, and structurally each flower always has a gynoecium and a developed androecium, even though functionally one or the other may be sterile (pistillodes or staminodes). Consequently, the determination of floral sexuality in the family is often difficult or even inconclusive in many taxa, and the available data often come from the analysis of herbarium material. This lack of detailed information on floral structure, development and function still prevent an accurate identification of floral sexuality in most members of Meliaceae, and also limits a comparison with the data known to other representatives of Sapindales, especially in relation to the structure and development of the carpels and stamens in the families most closely related, which are Rutaceae and Simaroubaceae. Studies on flower development associated with pollination studies and phylogenetic through comparative analysis, provide a better understanding on how these systems behave, and allow a more accurate classification of the sexual system present in particular species, leading to evolutionary data and assisting in clarifying kinship issues. The present dissertation addresses a detailed study of the structure of flowers of two Brazilian taxa (Trichilia claussenii and Guarea macrophylla subsp. tuberculate) belonging to the subfamily Melioideae, with emphasis on the organization and development of their sexual systems. Our study includes analysis of the external morphology, anatomy, vascularization, ontogeny, and histochemical tests of both species. We also analyzed the functional aspects of flowers of T. claussenii, related to floral sexuality, which was evaluated by means of pollination tests, associated to tests of pollen viability, stigmatic receptivity and morphoanatomic and ontogenetic analyzes. Among the main results, floral dimorphism was detected only in T. claussenii, which is likely gynodioecius, and provided with a peculiar sterility of the androecium in the female flower morphotype: pollen grains remain concealed by a secretion from the tapetum. In addition, we promote the discussion of pathways of the evolution of sexual systems within the Meliaceae, as well as of its main flower and fruit morphological characters, through hypotheses evaluated upon the current molecular phylogenetic framework of the family / Os sistemas reprodutivos das angiospermas são bastante diversos. Nas flores de Meliaceae (Sapindales) encontramos uma grande diversidade desses sistemas, sendo relatada a presença de plantas monoicas, dioicas e poligâmicas. No entanto, o dimorfismo sexual das flores nessa família é muito sutil, e estruturalmente cada flor sempre possui um gineceu e um androceu desenvolvidos, mesmo que funcionalmente um ou outro seja estéril (pistilódio ou estaminódio). Consequentemente, a determinação da sexualidade floral na família é muitas vezes difícil ou até mesmo inconclusiva em muitos táxons, sendo a maioria dos dados disponíveis provenientes da análise de material herborizado. A carência de informações mais detalhadas sobre estrutura, desenvolvimento e função, ainda limita muito uma acurada identificação da sexualidade floral em Meliaceae, assim como impede uma comparação com os dados conhecidos sobre outros representantes de Sapindales, especialmente em relação à estrutura e desenvolvimento do androceu e gineceu, nas famílias mais proximamente aparentadas a ela, que são Rutaceae e Simaroubaceae. Estudos sobre o desenvolvimento floral, associados a estudos de polinização e filogenia, por meio de análises comparativas, propiciam melhor compreensão de como esses sistemas se comportam, permitindo uma classificação mais acurada do sistema sexual presente numa determinada espécie, além de fornecer dados evolutivos importantes e auxiliar no esclarecimento de questões de parentesco. Neste contexto, a presente dissertação aborda um estudo detalhado da estrutura das flores de dois táxons brasileiros (Trichilia claussenii e Guarea macrophylla subsp. tuberculata) pertencentes à subfamília Melioideae, com ênfase na organização e desenvolvimento do sistema sexual. Tal estudo é composto por análise da morfologia externa, anatomia, vascularização, ontogenia e testes histoquímicos em ambos táxons. Também foram feitas análises dos aspectos funcionais das flores de Trichilia claussenii, relativos à sexualidade floral, por meio de testes de polinização, testes de viabilidade polínica, receptividade estigmática e análises morfoanatômicas e ontogenéticas. Entre os principais resultados, destacamos o dimorfismo floral detectado apenas em T. claussenii, espécie ginodioica na qual a esterilidade do androceu no morfotipo floral feminino é alcançada pela impossibilidade de liberação dos grãos de pólen, retidos por uma secreção do tapete. Além disso, promovemos a discussão de transições evolutivas do sistema sexual na história da família, bem como de outros caracteres morfológicos florais e de fruto, por meio de avaliação de hipóteses estruturadas sobre a filogenia molecular atual da família

Este trabalho foi realizado com o objetivo de avaliar o efeito de frações (em hexano, diclorometano, acetato de etila e hidroalcoólica) de extratos etanólicos de Trichilia pallida Swartz, Trichilia pallens C.DC. e Toona ciliata M. Roemer sobre Spodoptera frugiperda (J. E. Smith), e isolar, identificar e avaliar o efeito dos compostos dessas três meliáceas sobre o desenvolvimento e o metabolismo do inseto, com ênfase para o limonoide cedrelona. As frações causaram baixa mortalidade, mas houve grande redução de peso das lagartas com as frações em diclorometano de folhas e de ramos de T. pallida, de ramos de T. pallens e de folhas e de frutos de T. ciliata, além de maior duração da fase larval, redução do peso de pupas e alteração dos índices nutricionais, sendo a fração de ramos de T. pallida a de maior efeito tóxico e com fagodeterrência secundária, e a fração de folhas de T. ciliata sem efeito tóxico, mas apresentando fagodeterrência possivelmente primária. A partir da fração em diclorometano de frutos de T. ciliata obteve-se um triglicerídeo; da fração em acetato de etila de ramos de T. ciliata obteve-se o flavonoide (+/-)-catequina; da fração em hexano de folhas de T. pallida obteve-se o triterpeno damaradienol e da fração em diclorometano de ramos de T. pallens obteve-se a cumarina escopoletina. O triglicerídeo e a escopoletina causaram pequena mortalidade e redução de peso das lagartas por ingestão, enquanto a catequina causou apenas redução de peso. Por contato, a escopoletina também afetou a sobrevivência. O limonoide cedrelona, isolado do extrato bruto em hexano de caules de T. ciliata, apresentou o maior efeito, tanto por ingestão quanto por contato. Por ingestão, os valores estimados de CL50, CL90 e CE50 para a cedrelona aplicada sobre a dieta foram 365,33, 659,62 e 95,02 ppm, respectivamente, e após incorporação na dieta, os valores foram 119,05, 491,14 e 45,13 ppm, respectivamente. A cedrelona causou fagodeterrência em teste com chance de escolha e redução no consumo foliar no teste sem chance de escolha. A ingestão de cedrelona causou menor peso de lagartas e de pupas, aumento da duração da fase larval e da mortalidade de modo dose dependente, com efeitos subletais observados a partir de 24 ppm. Lagartas de quarto ínstar que ingeriram dieta contendo cedrelona a 300 ppm tiveram redução na eficiência de conversão do alimento ingerido (ECI) e digerido (ECD) e na taxa de crescimento relativo (RGR), enquanto o custo metabólico (MC), a taxa metabólica relativa (RMR) e a digestibilidade aproximada (AD) aumentaram, e a taxa de consumo relativo (RCR) não foi alterada, indicando efeitos tóxicos pós-ingestão e efeito fagodeterrente secundário, com a maior parte do alimento assimilado sendo utilizada no metabolismo. A atividade de proteases no mesêntero das lagartas que ingeriram dieta contendo cedrelona foi reduzida, assim como a quantidade de grupos heme, relacionados às monoxigenases do citocromo P450, enquanto a atividade de glutationa-S-transferases não foi alterada. A atividade de acetilcolinesterase no extrato enzimático de lagartas inteiras aumentou. A bioatividade da cedrelona e os possíveis modos de ação são discutidos. / This work was carried out to evaluate the effect of fractions (in hexane, dichloromethane, ethyl acetate and hydroalcoholic) of ethanolic extracts of Trichilia pallida Swartz, Trichilia pallens C.DC. and Toona ciliata M. Roemer to Spodoptera frugiperda (J.E. Smith ), and to isolate, identify and evaluate the effect of the compounds from the three Meliaceae on the larvae development and metabolism, with emphasis on the cedrelone limonoid. The fractions caused low mortality, but there was a great reduction in weight of larvae with dichloromethane leaves and stems fractions of T. pallida, stems of T. pallens and leaves and fruits of T. ciliata, in addition to longer duration of the larval stage, pupae weight reduction and changes on nutritional indices. The fraction of T. pallida stems caused the highest toxic effects and secondary phagodeterence, and the fraction of T. ciliata leaves showed probably primary phagodeterrence, but no toxic effect. From the dichloromethane fraction of T. ciliata fruits was obtained a triglyceride (unidentified), from the ethyl acetate fraction of T. ciliata stems was obtained the flavonoid (+/-)-catechin, from the hexane fraction of T. pallida leaves was obtained the triterpene dammaradienol and from the dichloromethane fraction of T. pallens stems was obtained the coumarin scopoletin. Scopoletin and triglyceride caused low mortality and larval weight reduction after ingestion, catechin caused only larval weight reduction. Scopoletin either affect survival by contact. The limonoid cedrelone, isolated from the crude hexane extract of stems of T. ciliata, was the most effective compound, either by ingestion or by contact. After ingestion, the estimated LC50, LC90 and EC50 values for cedrelone applied onto the diet were 365.33, 659.62 and 95,02 ppm, respectively, and after diet incorporation, the values were119.05, 491.14 and 45.13 ppm, respectively. Cedrelone caused feeding deterrence on choice test and reduced leaf consumption in the no-choice test. Cedrelone intake caused low weight gain by larvae and pupae, increased mortality and duration of larval stage in a dose-dependent manner, with sublethal effects observed at 24 ppm. Fourth instar larvae that ingested diet containing 300 ppm cedrelone showed reduced efficiency conversion of ingested (ECI) and digested food (ECD), reduced relative growth rate (RGR), increased metabolic cost (MC), relative metabolic rate (RMR) and approximatte digestibility (AD), but no change in relative consumption rate (RCR), suggesting toxic effects post ingestion and secondary phagodeterrence, in which most of the assimilated food was used in metabolism. The protease activity in the midgut of the larvae that ingested diet containing 300 ppm of cedrelone was reduced, as well the amount of heme groups related to cytochrome P450 monoxygenases in the midgut, but there was no change in the glutathione S-transferases activity. , There was an increase of acetylcholinesterase activity in the larvae bodies. Cedrelone bioactivity and the possible modes of action are discussed.

The Spodoptera frugiperda fall armyworm is considered the main pest of the maize culture. The alternative control of this pest by means of Azadirachta indica A Juss. (Meliaceae) has been sufficiently promising; however, few works describe the use of neem residues in its control. This work was divided into a literature review and two experimental chapters. The first had as objective to evaluate the toxicity of aqueous leaf extracts and neem seed pie in worm of S. frugiperda fed with laboratory treated maize leaves. As for the second, the objective was to evaluate the leaf and pie of the neem seed effect, in three ways of application in greenhouse. In chapter I, the determination of the CL50 was done with analysis of Probit at two season of evaluation, besides a factorial 2x2+1 scheme to evaluate the biometric insect data and regressions to mortality. In chapter II, the variance analysis was carried out, the measurements being compared by the Tukey and Kruskal-Wallis test at 5% of significance. The estimated values of the CL50 for the aqueous extracts neem with leaf and pie were of 0.38% (m/v) and 0.31% (m/v), respectively. In relation to the length of the worm, width of the head and weight of the insect, there was significant interaction between the season and the treatments tested. There was significant difference between the tested aqueous extracts, to the 5 and to the 10 day after the first application. The pie treatment in the leaf-liquid way was what obtained the lowest note of damages with 2.08 in the note scale, but did not differ from the treatment with pie in the soil way. In the analysis of the leaf area, after the consumption of +3 leaf, there was observed a significant difference between the treatments with pie in liquid way 93.86 cm2 and the control 66.46 cm2. In laboratory, S. frugiperda worms were more susceptible to the aqueous leaf extract than to the aqueous pie extract of neem in relation to the mortality. There was difference between the season of evaluation in relation to the length of the worm, width of the head and weight. In greenhouse, the aqueous extract based on the pie was the most efficient in the control of worm of S. frugiperda. The leaf way in form of powder was the least efficient. / Fundação de Amparo a Pesquisa do Estado de Alagoas / A lagarta-do-cartucho Spodoptera frugiperda é considerada a mais importante praga da cultura de milho. O controle alternativo desta praga com Azadirachta indica A. Juss. (Meliaceae) tem sido bastante promissor, porém poucos trabalhos descrevem o uso de resíduos de nim no seu controle. O trabalho foi dividido em uma revisão de literatura e dois capítulos experimentais. O primeiro teve por objetivo avaliar a toxicidade de extratos aquosos de folhas e torta da semente de nim em lagartas de S. frugiperda alimentadas com folhas de milho tratadas em laboratório. Já o segundo, objetivou avaliar o efeito de folha e torta da semente de nim, em três vias de aplicação em telado. No capítulo I, fez-se a determinação da CL50 com análise de Probit em duas épocas de avaliação, além de um esquema fatorial 2x2+1 para avaliar dados de biometria do inseto e regressões para mortalidade. No capítulo II, realizou-se a análise de variância, sendo as médias comparadas pelo teste de Tukey e Kruskal-Wallis a 5% de significância. Os valores estimados da CL50 para os extratos aquosos com folha e torta de nim foram de 0,38% (m/v) e 0,31% (m/v), respectivamente. Em relação ao comprimento das lagartas, largura da cabeça e peso do inseto, houve interação significativa entre as épocas e os tratamentos testados. Houve diferença significativa entre os extratos aquosos testados, aos 5 e aos 10 dias após a primeira aplicação. O tratamento torta na via foliar-líquida foi o que obteve a menor nota de danos com 2,08 na escala de notas, mas não diferiu do tratamento com torta na via solo. Na análise da área foliar após o consumo da folha +3, observou-se que houve diferença significativa entre os tratamentos com torta na via líquida (93,86 cm2) e a testemunha (66,46 cm2). Em laboratório, lagartas de S. frugiperda foram mais suscetíveis ao extrato aquoso de torta do que o extrato aquoso de folha de nim em relação à mortalidade. Houve diferença entre as épocas de avaliação em relação ao comprimento das lagartas, largura da cabeça e peso. Em telado, o extrato aquoso à base de torta foi o mais eficiente no controle de larvas de S. frugiperda. A via foliar em forma de pó foi a menos eficiente.

Este trabalho foi realizado com o objetivo de avaliar o efeito de frações (em hexano, diclorometano, acetato de etila e hidroalcoólica) de extratos etanólicos de Trichilia pallida Swartz, Trichilia pallens C.DC. e Toona ciliata M. Roemer sobre Spodoptera frugiperda (J. E. Smith), e isolar, identificar e avaliar o efeito dos compostos dessas três meliáceas sobre o desenvolvimento e o metabolismo do inseto, com ênfase para o limonoide cedrelona. As frações causaram baixa mortalidade, mas houve grande redução de peso das lagartas com as frações em diclorometano de folhas e de ramos de T. pallida, de ramos de T. pallens e de folhas e de frutos de T. ciliata, além de maior duração da fase larval, redução do peso de pupas e alteração dos índices nutricionais, sendo a fração de ramos de T. pallida a de maior efeito tóxico e com fagodeterrência secundária, e a fração de folhas de T. ciliata sem efeito tóxico, mas apresentando fagodeterrência possivelmente primária. A partir da fração em diclorometano de frutos de T. ciliata obteve-se um triglicerídeo; da fração em acetato de etila de ramos de T. ciliata obteve-se o flavonoide (+/-)-catequina; da fração em hexano de folhas de T. pallida obteve-se o triterpeno damaradienol e da fração em diclorometano de ramos de T. pallens obteve-se a cumarina escopoletina. O triglicerídeo e a escopoletina causaram pequena mortalidade e redução de peso das lagartas por ingestão, enquanto a catequina causou apenas redução de peso. Por contato, a escopoletina também afetou a sobrevivência. O limonoide cedrelona, isolado do extrato bruto em hexano de caules de T. ciliata, apresentou o maior efeito, tanto por ingestão quanto por contato. Por ingestão, os valores estimados de CL50, CL90 e CE50 para a cedrelona aplicada sobre a dieta foram 365,33, 659,62 e 95,02 ppm, respectivamente, e após incorporação na dieta, os valores foram 119,05, 491,14 e 45,13 ppm, respectivamente. A cedrelona causou fagodeterrência em teste com chance de escolha e redução no consumo foliar no teste sem chance de escolha. A ingestão de cedrelona causou menor peso de lagartas e de pupas, aumento da duração da fase larval e da mortalidade de modo dose dependente, com efeitos subletais observados a partir de 24 ppm. Lagartas de quarto ínstar que ingeriram dieta contendo cedrelona a 300 ppm tiveram redução na eficiência de conversão do alimento ingerido (ECI) e digerido (ECD) e na taxa de crescimento relativo (RGR), enquanto o custo metabólico (MC), a taxa metabólica relativa (RMR) e a digestibilidade aproximada (AD) aumentaram, e a taxa de consumo relativo (RCR) não foi alterada, indicando efeitos tóxicos pós-ingestão e efeito fagodeterrente secundário, com a maior parte do alimento assimilado sendo utilizada no metabolismo. A atividade de proteases no mesêntero das lagartas que ingeriram dieta contendo cedrelona foi reduzida, assim como a quantidade de grupos heme, relacionados às monoxigenases do citocromo P450, enquanto a atividade de glutationa-S-transferases não foi alterada. A atividade de acetilcolinesterase no extrato enzimático de lagartas inteiras aumentou. A bioatividade da cedrelona e os possíveis modos de ação são discutidos. / This work was carried out to evaluate the effect of fractions (in hexane, dichloromethane, ethyl acetate and hydroalcoholic) of ethanolic extracts of Trichilia pallida Swartz, Trichilia pallens C.DC. and Toona ciliata M. Roemer to Spodoptera frugiperda (J.E. Smith ), and to isolate, identify and evaluate the effect of the compounds from the three Meliaceae on the larvae development and metabolism, with emphasis on the cedrelone limonoid. The fractions caused low mortality, but there was a great reduction in weight of larvae with dichloromethane leaves and stems fractions of T. pallida, stems of T. pallens and leaves and fruits of T. ciliata, in addition to longer duration of the larval stage, pupae weight reduction and changes on nutritional indices. The fraction of T. pallida stems caused the highest toxic effects and secondary phagodeterence, and the fraction of T. ciliata leaves showed probably primary phagodeterrence, but no toxic effect. From the dichloromethane fraction of T. ciliata fruits was obtained a triglyceride (unidentified), from the ethyl acetate fraction of T. ciliata stems was obtained the flavonoid (+/-)-catechin, from the hexane fraction of T. pallida leaves was obtained the triterpene dammaradienol and from the dichloromethane fraction of T. pallens stems was obtained the coumarin scopoletin. Scopoletin and triglyceride caused low mortality and larval weight reduction after ingestion, catechin caused only larval weight reduction. Scopoletin either affect survival by contact. The limonoid cedrelone, isolated from the crude hexane extract of stems of T. ciliata, was the most effective compound, either by ingestion or by contact. After ingestion, the estimated LC50, LC90 and EC50 values for cedrelone applied onto the diet were 365.33, 659.62 and 95,02 ppm, respectively, and after diet incorporation, the values were119.05, 491.14 and 45.13 ppm, respectively. Cedrelone caused feeding deterrence on choice test and reduced leaf consumption in the no-choice test. Cedrelone intake caused low weight gain by larvae and pupae, increased mortality and duration of larval stage in a dose-dependent manner, with sublethal effects observed at 24 ppm. Fourth instar larvae that ingested diet containing 300 ppm cedrelone showed reduced efficiency conversion of ingested (ECI) and digested food (ECD), reduced relative growth rate (RGR), increased metabolic cost (MC), relative metabolic rate (RMR) and approximatte digestibility (AD), but no change in relative consumption rate (RCR), suggesting toxic effects post ingestion and secondary phagodeterrence, in which most of the assimilated food was used in metabolism. The protease activity in the midgut of the larvae that ingested diet containing 300 ppm of cedrelone was reduced, as well the amount of heme groups related to cytochrome P450 monoxygenases in the midgut, but there was no change in the glutathione S-transferases activity. , There was an increase of acetylcholinesterase activity in the larvae bodies. Cedrelone bioactivity and the possible modes of action are discussed.

One of the factors that affect the post-harvest behavior of seeds is provenance. Different geographical locations are characterised by different environmental conditions, hence, plant materials harvested from different locations may respond differently to laboratoryinduced stresses. The aim of the present study was to assess the role that provenance plays on the degree of recalcitrance of a single species – a factor that needs to be taken into consideration when choices are to be made for plant germplasm conservation. In this study, seeds of Trichilia dregeana, which have been shown to display recalcitrant post-harvest behavior, were harvested from four locations that were slightly different in climatic conditions: Mtunzini (MTZN), Durban (DBN), Pietermaritzburg (PMB) and Port Edward (P.ED), all within the KwaZulu-Natal province of South Africa. Clean seeds, whose aril and seed coat have been removed, were subjected to different drying and chilling stresses and their responses to the stresses are examined. Excised embryonic axes of the seeds were also subjected to flash (very rapid) drying and their responses to the stress are shown. Although the vegetation of these locations can be categorized as being sub-tropical, the present study suggests that there may be ‘degrees’ in the sub-tropical nature based on the rainfall and maximum temperature data. The ‘degree of sub-tropicality’ is suggested to be in the order MTZN > DBN > P.ED > PMB. Mean seed size assessed as seed length, width and fresh mass varied significantly across the four regions, with seeds from MTZN being the smallest and those from P.ED being the largest. The shedding water content of the embryonic axes of the seeds for 150 min. However, shoot production, root and shoot length and dry mass accumulation showed that axes of seeds from MTZN were the most adversely affected by rapid drying while those from PMB were the least sensitive. When clean whole seeds were dried slowly by burying in silica gel for 36 h, all seeds of the four provenances still retained more than 50% of their shedding water. MTZN seeds lost viability completely from the 24 h of slow drying while seeds from the other three locations retained some viability after 36 h. The order of survival of slow drying was MTZN < DBN < P.ED = PMB. Storage of cleaned whole seeds at chilling temperatures (3oC, 6oC and 16oC) caused increase in the water content of the embryonic axes of the seeds across the four locations. All seeds of the four provenances had lost more than 50% survival after they had been stored at 3oC for 10 weeks. Survival was completely lost from the 12th week for MTZN seeds, from the 14th week for DBN and P.ED seeds and from the 16th week for PMB seeds. There was no survival recorded for seeds across the four regions at the 18th week. The seeds were able to tolerate storage at 6oC for a little longer than those stored at 3oC. Only MTZN seeds completely lost viability at the 18th week; seeds from the other three locations retained some viability throughout the 18 weeks of storage. Storage at 16oC was the most tolerable, as all seeds from the four provenances maintained some viability until the 18th week in storage, with MTZN having the least survival and those from P.ED having the highest survival. Phylogenetic analysis of the internal transcribed spacer (ITS) region of the DBN and PMB samples showed intraspecific levels of genetic variation, and were separated by a genetic distance of 0.9%, an indicator that differences in storage behavior, chilling and desiccation sensitivity between seeds obtained from different collection localities may be genetically based. This study showed that MTZN seeds were the most sensitive, while seeds from PMB and P.ED were the most tolerant, to drying and chilling treatments, respectively. The prevailing climatic conditions may have a bearing on the responses observed in this study. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2011.

Neobeguea mahafalensis Leroy. and Cedrelopsis grevei Baill. are the two Madagascan species which were investigated in this work. Neobeguea mahafalensis Leroy. belongs to the Neobeguea genus of the Meliaceae family and is a plant unique to Madagascar. It is commonly referred to as "Handy" by the native people of Madagascar, who use it as a medicinal plant. The stem-bark of N mahafalensis which has been analysed in this work, was collected from the dry, thorny forests of the deep south of Madagascar. Most species found in this region are unique in the world and are highly specialised in adapting to the very dry climate. The hexane extract was found to yield a limonoid (compound I) which has not been previously reported as a natural product. The known pentacyclic triterpenoid, j3-amyrin (compound II) and stigmasterol (compound III), were also isolated. Cedrelopsis grevei Bail!. is one of seven species of the genus Cedrelopsis which are confined to Madagascar. This species, commonly referred to as "Katrafay" by the Madagascan people, has undergone intensive chemical investigation as prior inclusion ofthis species in the Meliaceae family has always been questionable. The South African species Ptaeroxylon obliquum (Thung.) Radlk., is a member of the Ptaeroxylaceaefamily which is found to be so chemically similar to Cedrelopsis that the latter has been placed in the Ptaeroxylaceae family. The stem bark of Cedrelopsis grevei was obtained from the dry southern part of Madagascar and yielded a variety of chromones and coumarins, as well as stigmasterol (compound III) and the pentacyclic triterpenoid, j3-amyrin (compound II). Two chromones were isolated from Cedrelopsis grevei, namely ptaeroxylinol (compound IV) and ptaeroglycol (compound V). Ptaeroglycol has been previously isolated _from this species as well as from Ptaeroxylon obliquum whereas ptaeroxylinol has only byen isolated from Ptaeroxylon obliquum. Six coumarins were isolated from Cedrelopsis grevei in tillS study, all of which were 6,7-dioxygenated coumarins. These included the known compounds, scoparone (compound VI), O-methylcedrelopsin (compound VIII), norbraylin (compound X) and cedrelopsin (compound IX), as well as compound VII and compound XI which . have not been reported previously. No limonoids were isolated from this species in this investigation. / Thesis (M.Sc.)-University of Natal, 1997.

The thesis outlines an investigative study of the supercritical fluid extraction (SFE) of organic natural products from two Meliaceae species. Extractions from ground wood, bark and seeds of the selected species were studied. Qualitative and quantitative studies were performed using a number of techniques. In the qualitative study, both off-line and on-line combination of micro-SFE with capillary gas chromatography (SFE-GC) were performed on the wood and bark of Cedrela toona to show the applicability of the technique in the analysis of semi-volatile components from plant matrices. Results for the on-line and off-line SFE-GC were comparable and indicated that the on-line studies could be used to predict results obtainable from large scale SFE. Dynamic SFE of the limonoid (cedrelone) from the wood of Cedrela toona using pure and modified carbon dioxide was studied on the basis of a theoretically-derived dynamic extraction model. Extracts were collected for different lengths of time in order to investigate the extraction kinetics of this compound. The theoretically-derived model which involved extrapolating data obtained from shorter extraction times was used to estimate the amount of the compound present in the wood. The estimated quantitative results were found to be comparable to exhaustive extractions using liquid hexane as well as methanol-modified carbon dioxide. Further, data from the SFE extractions were fitted into the model to produce a characteristic kinetic curve from which factors controlling the extraction of the specific compound could be predicted. Following the dynamic extraction study, a statistical optimisation strategy was used to propose a model equation for the extraction of cedrelone from the wood of Cedrela toona. As the preliminary step, a screening design utilising a two level, three-factor full factorial analysis was used to study the effects of the variables pressure, temperature and the length of extraction time on the yields of cedrelone from the wood of Cedrela toona. By a statistical analysis of variance (ANOVA) at the 95% confidence level on the preliminary data collected, pressure and temperature were found to be the significant variables influencing the yields of the compound. Finally response surface methodology using the central composite design was used in an attempt to determine the maximum response space for the pressure and temperature effects by plotting a 3-dimensional response surface graph. An ANOVA study at the 99% confidence level was then employed to establish the true model equation for the extraction. / Thesis (M.Sc.)-University of Natal, 1995.

The wood, leaf and seed extracts of Apodytes dimidiata, Turraea floribunda and Turraea obtusifolia were examined. Two new limonoids belonging to the Toonafolin group were isolated from the seeds, two known havanensin-type limonoids were isolated from the leaves and both stigmasterol and sitosterol were isolated from the wood of Turraeafloribunda. Sitosterol as well as a limonoid which could not be characterised were isolated from the seeds, phytol, melianone and a protolimonoid similar to sapelin-F were isolated from the leaves and three protolimonoids: melianodiol, melianotriol and 7,8-dihydroturraeanthin 3-acetate were isolated from the wood of Turraea obtusifolia. An ester was isolated from the seeds of Apodytes dimidiata. Appropriate reactions were performed, where possible, on the compounds isolated. / Thesis (M.Sc.)-University of Natal, Durban, 1990.

Esta pesquisa teve o objetivo de avaliar o efeito de derivados das meliáceas Azadirachta indica (nim), Melia azedarach e Trichilia pallida e os fungos entomopatogênicos Metarhizium anisopliae (isolado 1037) e Beauveria bassiana (isolado 634) visando ao controle do cupim subterrâneo Heterotermes tenuis. Os derivados vegetais foram avaliados em relação à toxicidade e repelência para o cupim. A formulação comercial Nimkol®, à base de folhas de nim, foi tóxica para o cupim, em concentrações de 0,3% de ingrediente ativo ou superiores. Não foi constatada a transmissão do Nimkol de indivíduos alimentados com esse produto para outros indivíduos. Os demais extratos vegetais estudados não apresentaram toxicidade significativa para H. tenuis. Nenhum dos produtos avaliados foi repelente a ponto de evitar a construção de galerias em placas com ágar ou provocar o fechamento das mesmas. Entretanto, em testes de escolha em arenas de preferência, H. tenuis demonstrou repelência pelo extrato aquoso de folhas de nim (5%). Os demais derivados avaliados, incluindo o Nimkol, não foram repelentes para o cupim. O efeito dos derivados vegetais e dos entomopatógenos na sobrevivência de H. tenuis, em forma independente e associada, foi estudada em laboratório e em condições de campo, visando avaliar um possível efeito estressor dos derivados vegetais sobre o cupim. Testes de compatibilidade in vitro indicaram resposta dependente da concentração do Nimkol, para a inibição do crescimento de colônias, da produção e da germinação de conídios dos entomopatógenos. A associação de extratos vegetais e entomopatógenos, em geral, diminuiu a atividade fungitóxica sobre H. tenuis. Entretanto, observou-se benefícios da associação de Nimkol (0,2 a 0,4% i.a.) com os isolados de B. bassiana e M. anisopliae quando houve um mínimo de 24 horas de diferença entre a aplicação do produto vegetal e dos fungos no alimento dos cupins. Os resultados de campo para Nimkol, M. asinopliae e a associação de ambos, mostraram tendências semelhantes às observadas para esses tratamentos em laboratório, embora com menores níveis de mortalidade. / The objective of this research was to evaluate the effect of by-products of the Meliaceae Azadirachta indica (neem), Melia azedarach and Trichilia pallida, and of the entomopathogenic fungi Metarhizium anisopliae (isolate 1037) and Beauveria bassiana (isolate 634) in the control of the subterranean termite Heterotermes tenuis. The vegetal by-products were evaluated in relation to the toxicity and repellency for the termite. The commercial formula Nimkol&#63720;, obtained from neem leaves, was toxic for the termite at concentrations of 0.3% a.i. and higher. There was no detected transmission of the Nimkol from individuals fed with the product to other individuals. The rest of the vegetal extracts were not significantly toxic for H. tenuis. None of the tested products was repellent to the extent of preventing the gallery construction in agar plates or causing them to be closed. In selection experiments on preference, H. tenuis showed repellency towards the aqueous extract of neem leaves (5%). The rest of the by-products tested, including Nimkol-L, were not repellent for the termite. The effect of the vegetal by-products and the entomopathogens, independently and associated, was studied under field and laboratory conditions, looking for a possible stressing effect of the vegetal by-products on the termite. In vitro compatibility tests showed a response of the Nimkol-L, dependent on the concentration, on the growth of colonies, production and germination of conidia of the entomopathogens. The association of entomopathogens and vegetal extracts decreased in general the toxic activity of the fungi over H. tenuis. With a minimal difference of 24h between the application of the vegetal product and the fungi in the food of the termites, a beneficial association was detected between Nimkol-L and isolates of B. bassiana and M. anisopliae. The field results for Nimkol-L, M anisopliae and the combination of the two, showed a trend similar to the one observed in the laboratory results, but with lower mortality levels.

This work describes the isolation and structural elucidation of extractives from four species of the Meliaceae and one of the Simaroubaceae families. All five species examined are endemic to the island of Madagascar. One novel seco-ring A protolimonoid with a bourjotinolone A-type side-chain was isolated from Turraea sericea, while Malleastrum antsingyense yielded one known and one novel limonoid of the vilasinin group. Neobeguea leandreana was found to contain three novel limonoids of the phragmalin class, including a relatively rare 17-keto seco-ring D compound and one containing a oxidized C-19 methyl group. Quivisia papinae has afforded eight novel and five known protolimonoids and limonoids of the azadiradione, evodulone, and mexicanolide classes. Included among these are a mexicanolide group limonoid with a 17-keto seco-ring D, and two further mexicanolide limonoids containing a hitherto unreported 9a,11a-epoxide ring and a Δ 9(11)-double bond. One C19 and four C20 quassinoids, of which one is novel, together with a known but rare triterpenoid, were isolated from the Madagascan Simaroubaceae Samadera madagascariensis. These findings support the suggestion that this species is closely related to, if not synonymous with, the companion species Samadera indica and Quassia indica. A literature survey on the effect of structural variations in ring B on coupling constants in 11,12-disubstituted havanensin-group limonoids was also undertaken, resulting in the observation of a remarkable correlation between ring structure and coupling constant values for a wide range of compounds isolated from different sources. An explanation for these observations is advanced. / Thesis (Ph.D.)-University of Natal, Durban, 2001.