Browsing by Author "Mulholland, Dulcie Aca."

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An analysis of Sappi Saiccor's effluent streams.
(2003) Ismail, Fathima.; Marsh, Jeremy J.; Mulholland, Dulcie Aca.
SAPPI SAICCOR is a pulp and paper mill situated in Umkomaas, 50 kms south of the port of Durban in South Africa. It was the first company to produce high grade dissolving pulp from the Eucalyptus tree and is currently the world's largest manufacturer of chemical cellulose. SAICCOR is one of the few pulp and paper mills that produces its dissolving pulp by the acid sulphite process using both calcium and magnesium as bases in the form of calcium bisulphite and magnesium bisulphite. Four streams of effluent are produced during their process, namely, the calcium spent liquor, the magnesium pulp condensate and two streams from the bleaching stages. An acid hydrolysis of the effluent streams yielded a range of organic compounds such as lignans and lignin - type precursors as well as a triterpenoid. Column chromatography and thin layer chromatography, using various ratios of hexane, dichloromethane, ethyl acetate and methanol, were carried out in isolating and purifying the compounds. The structures of these compounds were determined using NMR spectroscopic and mass spectrometric techniques.
Artificial neural networks for the classification of Meliaceae extractives.
(1998) Fraser, Leigh-Anne.; Mulholland, Dulcie Aca.
The goal of this project was the development of a computer-based system using artificial intelligence to classify the limonoids, protolimonoids and triterpenoids isolated from the family Meliaceae by the Natural Products Research Group of the University of Natal, Durban. A database of samples was obtained between 1991 and 1996, part of which time the author was a member of the group and isolated compounds from Turraea obtusifolia and Turraea floribunda. Over and above the problem of complexity and similarity in structures of the above mentioned natural products, are other difficulties. These include very small amounts of sample being isolated producing very weak peak signals in the C-13 NMR spectra, extraneous peaks in the NMR spectra due to different impurities and instrument noise, non-reproducible spectra due to the pulsed Fourier transform intervals and the nuclear Overhauser effect, impure samples often isolated as stereoisomeric mixtures or as mixed esters and superposition of peak signals in the NMR spectra due to carbons in the same environment within the same compound. These factors make identification by traditional computational and expert systems impossible. As a result of these shortcomings, the author has developed a novel approach using artificial neural network techniques. The artificial neural network system developed used real data from the 300 MHz NMR spectrometer in the Department of Chemistry, Durban. The system was trained to discriminate between limonoids, triterpenoids and flavonoids/coumarins from the C-13 NMR spectra of pure, impure and unseen compounds with an accuracy of better than 90%. Further differentiation of the glabretals from the rest of the protolimonoids as well as from the rest of the triterpenoids showed similarly significant results. Finally, individual limonoid discrimination within the limonoid dataset was extremely successful. Apart from its application to the extractives from Meliaceae, the methodology and techniques developed by the author can be applied to other sets of extractives to provide a robust method for the spectral classification of pre-identified natural products.
Characterisation of SAPPI SAICCOR pulp mill's effluent.
(2001) Moodley, Brenda.; Marsh, Jeremy J.; Mulholland, Dulcie Aca.
SAPPI SAJCCOR, whose factory is situated south of Durban, South Africa, is one of the few paper and pulp mills that uses the acid sulphite process with calcium and magnesium bases to produce a high-grade cellulose pulp. Four streams of effluent, namely, the calcium - spent liquor stream, the magnesium condensate stream and two streams from the bleaching effluent are produced during this sulphite pulping process and they contain a variety of organic compounds extracted from the wood. Characterisation of the effluent was based on isolation using column chromatography and identification using NMR techniques. A range of constituents, such as lignans and lignin - type precursors, a trilerpenoid and fatty acids were isolated and identified. X-ray diffraction was used to identify an inorganic residue obtained from the calcium - spent liquor stream and gas chromatography/mass spectrometry was used to identify a wax residue. which builds up in the process. In addition to this, the carbohydrate content of the four streams of effluent was detennined using UV/visiblc spectroscopy.
A chemical investigation of a KwaZulu-Natal medicinal plant, Momordica foetida Schum. & Sond.
(1994) Sewram, Vikash.; Osborne, Roy.; Mulholland, Dulcie Aca.
Momordica foetida Schum. & Sond. (Cucurbitaceae), locally known as iNtshungu, is widely used by the Zulu people of Natal-KwaZulu for the treatment of a variety of ailments. The dried leaves leaves and stems of this plant was subjected to soxhlet extraction by refluxing with hexane, chloroform and methanol successively. Thin layer chromatography of the chloroform extract of the leaves revealed a multiplicity of compounds. The chloroform extract was further partitioned with sodium hydroxide resulting in an organic and aqueous phase. The organic phase, containing extract A, afforded two compounds, viz. compounds 1 and 2. The basic aqueous fraction was neutralised and re-extracted with chloroform to give extract B, affording five compounds, viz. compounds 3,4,5,6 and 7. Structural elucidation was accomplished by techniques such as IH and 13C NMR spectroscopy, HETCOR, COSY, FTIR and High Resolution Mass Spectrometry. Compounds 1 and 2 were identified as cucurbitane triterpenoids known as momordicines which had been previously discovered in the related species of this plant, Momordica charantia L. The remaining five compounds were identified as novel compounds, although natural derivatives of compounds 6 and 7 had been isolated previously from Momordica charantia L. Compounds 3-7 were each isolated as an epimeric mixture but it was possible to select the resonances corresponding to the major epimer. These five epimers were respectively identified as 5, 19-epoxy-19(R)-hydroxy-25-methoxy-5β- cucurbita-6,23-diene-3β-ol [102], 5,19-epoxy-19(R),25-dihydroxy-5β-cucurbita- 6,23-diene-3β-ol [103], 5,19-epoxy-19(R)-methoxy-25-hydroxy-5β-cucrbita- 6,23-diene-3β-ol [104], 5,19-epoxy-25-methoxy-5β-cucurbita-6,23diene- 3β-ol [105] and 5,19-epoxy-19(R),25-dimethoxy-5β-cucurbita-6,23diene- 3β-ol [106]. Appropriate reactions were performed, where possible, on the compounds isolated in order to confirm their identity.
The chemical investigation of four medicinal plants.
(2000) Langlois, Angela.; Mulholland, Dulcie Aca.
This thesis describes a phytochemical investigation of four medicinal plants, namely, Agave attenuata (Agavaceae), Balanites maughamii (Balanitaceae), Astrotrichilia parvifolia (Meliaceae) and Combretum fragrans (Combretaceae). Investigations of A. attenuata and B. maughamii were undertaken as biological studies have shown that these plants possess anti-bilharzial properties. Schistosomiasis is an important public health issue in South Africa and attempts to deal with infected rural communities have forced scientists to focus their attention on snail control using plant molluscicides. A. attenuata yielded two glycosides, timosaponin A III (compound I) and 5?-pregn-16-en-20one- 3?-O-tetrasaccharide (compound II), while a coumarin, scopoletin (compound III) and a sterol, stigmasterol (compound IV) were isolated from B. maughamii A dammarane, shoreic acid (compound V) was isolated from A. parvifolia, this formed part of an ongoing investigation into the Meliaceae of Madagascar. Plants of the family Combretaceae are widespread in Africa and are used by traditional healers for a wide range of illnesses. The leaves and bark are used abundantly, however, the winged fruits are never eaten as they are highly toxic to animals and humans. The leaf surface is covered with epidermal scale-like trichomes through which acidic triterpenoid mixtures are secreted. Six lupane-type triterpenoids were isolated from C. jragrans, namely, lupeol (compound VI), lupenone (compound VII), lupeol 3?- docosanoate (compound VIII), lupeol 3?-eicosanoate (compound IX) hennadiol (compound X) and 30hydroxylupenone (compound XI). All the above compounds were isolated by column chromatography and the structures were elucidated by means of NMR spectroscopy, mass spectrometry and infra red spectroscopy.
The chemical investigation of Ledebouria ovatifolia, Clivia caulescens and Haemanthus pauculifolius.
(1999) Pohl, Tracy-Lee.; Mulholland, Dulcie Aca.; Crouch, Neil Robert.
Ledebouria ovatifolia (Bak.) lessop, Clivia caulescens R.A.Dyer and Haemanthus pauculifolius Snijman & Van Wyk were the three species investigated in this work. Ledebouria ovatifolia belongs to the family Hyacinthaceae (Liliaceae sensu lato) and, to date, the chemical composition of this species has not been investigated. Members of this family are widely distributed, but are particularly well represented in Southern Africa. The Ledebouria genus was formerly classified as part of the Scilla genus from which a large number of naturally occurring oxygen heterocycles known as homoisoflavonoids have been isolated. In this work the bulbs of L. ovatifolia were investigated and two compounds were isolated. These were the homoisoflavonoid, 5,7-dihydroxy-3-(4'-hydroxybenzyl)-4-chromanone and the chalcone, 6',2'-dimethoxy-4,4'dihydroxychalcone, both of which are known naturally occurring compounds. Clivia caulescens and Haemanthus pauculifolius are both members of the Amaryllidaceae family. The plants of the Amaryllidaceae family form a large group of over sixty genera, which are concentrated mainly in Southern Africa. Plants from this family have been extensively used in traditional medicines and many have pharmacological properties. The compounds responsible for most of these effects are a group of isoquinoline alkaloids, which are found almost exclusively in plants belonging to this family. The alkaloids isolated from plants belonging to this group are known to cause poisoning in low doses and can cause excessive salivation and diarrhoea. Higher doses of the active compounds can cause CNS depression and large enough doses can prove fatal. Although many of these alkaloids are harmful to man, some of the unique Amaryllidaceae alkaloids exhibit anti-tumour and anti-viral activities, and are thus potentially beneficial to man. The Clivia genus is endemic to South Africa and the most common species, C. miniata, is used by traditional healers to facilitate childbirth and as a snake bite remedy. In this chemical investigation both the bulbs and the leaves of C. caulescens were investigated. The ethanol extract of the bulbs yielded four alkaloids, hippeastrine, haemanthamine, lycorine and ll-(S)-hydroxyvittatine. The investigation of the leaf extract also yielded lycorine and hippeastrine as well as an additional alkaloid sternbergine. Haemanthus pauculifilius is a recently described member of the Haemanthus genus, which consists of 27 taxa that are restricted to Southern Africa and Namibia. In this chemical investigation the ethanol extract of the bulbs and leaves yielded the common triterpenoid sitosterol as well as two novel 5,11-methanomorphanthridine type alkaloids, montanine hydrochloride and manthidine.
The chemical investigation of Ledebouria zebrina and Scilla natalensis.
(2001) Moodley, Nivan.; Crouch, Neil Robert.; Mulholland, Dulcie Aca.
Ledebouria zebrina and Scilla natalensis Planch were the two species investigated in this work. Ledebouria zebrina belongs to the Hyacinthaceae (Liliacea sensu lato) and to this date, the chemical composition of this species has not been investigated. Members of this family are found in southern Africa. The Ledebouria genus was formerly classified as part of the Scilla genus from which a large member of naturally occuring oxygen heterocycles known as homoisoflavanones have been isolated. In this work the bulbs of L. zebrina were investigated and five compounds were isolated. Three compounds were of the homoisoflavanone type while the remaining two belong to the eucosterol type triterpernoids. Scilla natalensis Planch also belongs to the Hyacinthaceae family. Previous chemical investigations of the bulbs of this plant yield two homoisoflavanones of the 3-benzyl-4- chromanone type. Members of this family are mostly found in the Eastern parts of the country, ranging from the Eastern Cape to Mpumalanga province including Lesotho and Swaziland. The bulbs of this plant were investigated and this yielded ten compounds. The structures of the isolated compounds were elucidated using spectroscopic methods.
The chemical investigation of the Amaryllidaceae and Hyacinthaceae.
(2004) Moodley, Nivan.; Mulholland, Dulcie Aca.; Crouch, Neil Robert.
This work is an account of investigations into the chemistry of members of the Amaryllidaceae and Hyacinthaceae families. The plants of the family Amaryllidaceae are a large group comprising over sixty genera and more than a thousand species. They are widely distributed, but are found more richly in the tropics, with a particularly high density in South Africa, with smaller centers of diversity in Andean South America and the Mediterranean. Amaryllidaceae plants have been extensively used by local traditional healers and have been reported to have numerous pharmacological uses. The alkaloids isolated from this family are a group of isoquinoline alkaloids found exclusively in this family. Plants belonging to two Amaryllidaceae genera were investigated phytochemically, one from each of the sub-tribes Crinineae and Amaryllidineae were investigated phytochemically. Brunsvigia natalensis is used in local traditional medicine to "straighten bones of children", treat barrenness in women and ease childbirth. This is the first phytochemical investigation of Brunsvigia natalensis, and yielded two new alkaloids, a new ceramide type compound and a known flavanoid. A comparative phytochemical investigation was carried out on the bulbs and seeds of Crinum stuhlmanni, which resulted in a number of different alkaloids being isolated from the seeds and bulbs of this plant. The southern African Hyacinthaceae is a large and chemically morphologically diverse group of plants. This family comprises approximately sixty-seven genera and nine hundred species worldwide, of which twenty-seven genera and three hundred and sixty - eight species are found locally. There are five sub-families of which three occur in southern Africa. The chemical constituents of this family can be divided into four classes, namely homoisoflavanones, steroidal compounds, bufadienolides and miscellaneous compounds. These plants are used in local traditional medicine for treating ailments such as hangovers, rheumatic fever, sprains and even cancer. The phytochemistry of three Hyacinthaceae plants was studied. The phytochemical investigation of Drimia macrocentra and Urginea riparia yielded a novel bufadienolide glycoside. These glycosides are quite unusual with the glycone attached to the aglycone at C-2 and C-3 and this has only been reported only once before in this family. The phytochemical investigation of Ledebouria revoluta yielded a number of homoisoflavanones. These homoisoflavanones have been shown to have anti-inflammatory activity and all of the compounds isolated in this work have been screened for this activity. Structural elucidation was carried out using spectroscopic methods such as NMR, MS, UV and IR.
Ethyl N-bromo-alkylcarbamates as heterocyclic precursors and extractives from Oceanapia sp.
(2001) Dovey, Martin Charles.; Gerber, Jacobus Petrus.; Mulholland, Dulcie Aca.
The synthesis of p-lactams has been of foremost importance since the discovery of penicillin by Sir Alexander Fleming, in 1928, and its susequent structure elucidation in 1945. Ethyl N-2-bromo-alkylcarbamates show considerable potential as precursors to p- lactams. In the past, p-lactams have been prepared by many methods, none of which have involved 2-3 bond formation. The proposed ring closure using ethyl N-2-bromoalkylcarbamate involves 2-3 bond formation, making this method of synthesis novel. This work describes two attempted methods of cyclisation. The first using a Grignard reagent, and the second, using abstraction of an acidic proton a to a phosphonate group. These methods of intramolecular cyclisation were based on analogous intermolecular additions, which are also described. The second method was also used to determine the general potential of ethyl N-bromo- alkylcarbamtes as precursors to other heterocyclic systems.
Extractive from seven African medicinal plants.
(2003) Langlois, Angela.; Mulholland, Dulcie Aca.
This PhD thesis describes a phytochemical investigation of seven medicinal plants, namely, Ledebouria ovatifolia (Hyacinthaceae), Eucomis pole-evansii (Hyacinthaceae ), Lachenalia rub ida (Hyacinthaceae), Drimia capitata (Hyacinthaceae ), Papaver aculeatum (Papaveraceae), Spilanthes mauritiana (Asteraceae) and Tachiadenus longiflorus (Gentianaceae). The southern African Hyacinthaceae is a large, chemically and morphologically diverse group of plants. Plants of the genus Ledebouria are used extensively by traditional healers in Kwazulu-Natal, particularly in enemas and as purgatives for both humans and cattle. Investigations of Ledebouria ovatifolia led to the isolation of three compounds, a novel norlignan, a class, which has never before been found in this family, and two eucosterol-type compounds. Chemical investigations of Eucomis pole-evansii and Lachenalia rub ida have revealed the presence of two homoisoflavonoids of the 3-benzyl-4-chromanone type, a novel 3-benzylidene-4- chromanone type homoisoflavonoid as well as a novel 3-benzylchromone. Investigations of Drimia capitata have yielded a novel bufadienolide and its glycoside Plants of the family Papaveraceae have been of great interest chemically, as they contain alkaloids such as morphine and codeine. Morphine is an intense analgesic used to treat chronic pain, while codeine is milder and is found in cough syrups and headache remedies. The species Papaver aculeatum is thought to be a premature member of the Papaveraceae and it was thought that it might contain precursors to these alkaloids. This plant yielded an alkaloid, (+ )-N-acetylanonaine. In South Africa, the African plant Spilanthes mauritiana (Asteraceae), is used medicinally by the Zulus as an oral local analgesic for the relief of toothache. Other medicinal usage of this plant includes healing broken limbs, stomach-ache, diarrhoea, bladder complaints and headaches. This plant yielded one known and one novel isobutylamide. The known isobutylamide, spilanthol, has been attributed with larvicidal and other insecticidal properties. Members of the family Gentianaceae commonly accumulate bitter substances called iridoids. The species Tachiadenus longiflorus yielded the known triterpenoid, oleanolic acid; two known coumarins, scopoletin and scoparone; and what appears to be an iridoid derivative. Syntheses of aesculetin, scoparone and isoscopoletin were also performed for comparison purposes. The final chapter in this thesis is an attempt to synthesise the norlignan isolated from Ledebouria ovatifolia. This procedure involves firstly the synthesis of the appropriate chalcone, secondly the formation of the appropriate Grignard reagent and its attachment to the chalcone, thirdly reduction of the vinyl ketone to form the vinyl alcohol and finally dehydration to form the norlignan. This unfortunately did not occur, however a novel cyc1isation product was formed and was identified as (E)-3- vinyl-l-( 4 '-hydroxypheny 1)-3",4 "-dimethoxyindene.
Extractives from eucomis montana and agapanthus inapertus.
(2003) Pillay, Bavani.; Mulholland, Dulcie Aca.; Koorbanally, Neil Anthony.
Two species belonging to different families were investigated, Eucomis montana from the Hyacinthaceae and Agapanthus inapertus from the Agapanthaceae. To date no previous chemical investigation on Eucomis montana has been reported. Eucomis species are routinely harvested, processed and sold for the treatment of various ailments ranging from toothache, gastro-intestinal ailments, pain-producing ailments and venereal and urinary diseases. Members of the genus have shown to contain steroidal compounds and homoisoflavonoids. In this work one nortriterpenoid, a eucosterol type derivative and eleven homoisoflavonoids belonging to four classes, the 3-benzyl-4-chromanone, the 3-benzyl-3-hydroxy-4-chromanone, the 3-benzylidenyl-4-chromanone and the scillascillin type were found in the bulbs of Eucomis montana. Agapanthus species are also used by a number of African tribes medicinally. The bulbs and rhizomes of this family have been reported to contain steroidal saponins and sapogenins. In this work the roots of Agapanthus inapertus have been investigated and a tignan precursor and a lignan have been found. Structures of the compounds isolated were determined using spectroscopic techniques.
Extractives from Neobeguea mahafalensis and Cedrelopsis grevei.
(1997) Kotsos, Maria Paraskevi.; Mulholland, Dulcie Aca.
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.
Extractives from samadera madagascariensis and toddaliopsis bremekampii.
(2004) Naidoo, Dashnie.; Mulholland, Dulcie Aca.
This work involves the isolation, structural elucidation and the biological screening of compounds from the Madagascan Samadera madagascariensis and Toddaliopsis bremekampii from South Africa. Samadera madagascariensis Jussieu (locally known as "fatriana") belongs to the Simaroubaceae family and is endemic to Madagascar. The leaves of Samadera madagascariensis are used in Madagascar for the treatment of stomach aches and dysentry, and the juice of the fresh leaves is used to treat wounds and burns. Samadera madagascariensis leaves were investigated in this work for the presence of quassinoids and triterpenoids. Eighteen compounds, including seven quassinoids: samaderine A (i), the novel 5~,6-dihydrosamaderine A (ii), the novel 2chlorosamaderine A (iii), the novel samaderine DN (iv), samaderine B (v), cedronin (vi) and the novel 3,4~-dihydrosamaderine C (vii), and eleven triterpenoids: the novel protosamaderine A (viii), 1,2-dihydrobruceajavanin A (ix), chisocheton compound A (x), the novel protosamaderine B (xi), the novel protosamaderine C (xii), the novel protosamaderine D (xiii), the novel protosamaderine E (xiv), the novel protosamaderine F (xv), the novel protosamaderine G (xvi), the novel protosamaderine H (xvii) and the novel protosamaderine I (xviii) were isolated from the Samadera madagascariensis leaves. The quassinoids isolated in this work are of the C18 and C19 classes, and only five of the C18 type have been published previously. Quassinoids exhibit a range of biological activities such as antileukemic, antiviral, antimalarial, anti-inflammatory, antifeedant and amoebicidal. 2-Chlorosamaderine A (iii), cedronin (vi) and 3,4~-dihydrosamaderine C (vii) were found to have anticarcinogenic properties. The triterpenoids isolated in this work are of the protolimonoid type and protolimonoids are known to exhibit anticarcinogenic and antifungal properties. Toddaliopsis bremekampii I. Verd. belongs to the Rutaceae family. Members of the Toddaliopsis genus are found in the warmer regions of southern Africa. The phytochemistry of this species and genus has not been investigated previously, however, other members of the Rutaceae have yielded a wide range of alkaloids and other compounds. The leaves and branches of Toddaliopsis bremekampii were investigated in this work and yielded four novel acridone alkaloids: 1,2,3trimethoxyacridone (i), 1,2,3-trimethoxy-1 O-acetoxymethylacridone (ii), 1-hydroxy-2,3-dimethoxy10- acetoxymethylacridone (iii) and 1,2,3-trimethoxy-1 O-methoxy methylacridone (iv). Acridone alkaloids are known to have antineoplastic and antitumour properties. These alkaloids were active in the chemiluminescence assay, which showed the suppression of the reactive oxygen species generated by polymorphonuclear leukocytes (PMNs) in humans. The PMNs play a key role in the host's defence. However, the reactive oxygen species generated as a result of this defence mechanism cause tissue damage.
Extractives from the amaryllidacea and the fabaceae.
(1999) Koorbanally, Neil Anthony.; Mulholland, Dulcie Aca.; Crouch, Neil Robert.
This work is an account of investigations into the chemistry of one of the members of the Amaryllidacae family, Ammocharis coranica, and one of the members of the Fabaceae family, Sophora velutina. Chapter one is an account of the extractives from the bulbs of Ammocharis coranica. In all, twelve compounds, eight alkaloids and four cycloartane compounds have been isolated of which one alkaloid and one cycloartane compound have not been described previously. Plants belonging to the Amaryllidacae family have been used by traditional healers, especially in Africa, to treat a range of illnesses and diseases. The alkaloids isolated from these plants have been shown to exhibit responses to muscle stimulant, antiviral, antifungal, antiyeast, antimalarial, cytotoxic and antitumoural activities. Ammocharis coranica is used by the Zulu tribe in South Africa to treat any illness believed to be caused by witchcraft. Alkaloids from the three most common types among the isoquinoline group were found in this species. These are lycorine, 1-O-acetyllycorine, hippadine, acetylcaranine, and the novel 1-O- acetyl-9-norpluviine from the lycorine type, 6-α-hydroxypowelline from the crinine type and hamayne and crinamine from the haemanthamine type. Cycloartane compounds have not been reported previously from the Amaryllidaceae family. All four cycloartane compounds had a common side chain, containing an olefinic methylene group at position 24, but differed in their substituents at positions 3 and 4. These compounds were found to be 24-methylenecycloartan-3β-ol, cycloeucalenol, cycloeucalenone and the novel compound 4-methylenepollinastanone. Chapter two is an account of the extractives from the seeds of Sophora velutina. The seeds of other Sophora species have been used in traditional ceremonies by the Indians of the Southwest United States and adjacent Mexico because of their hallucinogenic activity. The seeds of Sophora velutina subsp. zimbabweensis found in Zimbabwe are suspected to have historically been used by the natives for their hallucinogenic properties. These plants have been known to contain several quinolizidine alkaloids, flavonoids and isoflavonoids. One alkaloid, N-methylcytisine and two isoflavones, pseudobaptigenin and calycosin, as well as the common phytosterol, β-sitosterol were isolated from the seeds of this species. N-methylcytisine is a common quinolizidine alkaloid, isolated previously from several Sophora species and pseudobaptigenin and calycosin are well known isoflavones, isolated previously from several species in the Fabaceae.
Extractives from the Hyacinthaceae.
(2000) Koorbanally, Chantal.; Mulholland, Dulcie Aca.
Four species belonging to the Hyacinthaceae family were investigated. The taxonomy of the Hyacinthaceae is currently under review and therefore compounds isolated from these plants could provide valuable chemical evidence which taxonomists could find very useful. The bulbs of the species investigated have been reported to have widespread uses in traditional African medicine, being used by different local tribes to treat a variety of ailments ranging from use as a soothing medicine for pregnant women to their being used as an ethnoveterinary medicine. The bulbs of Ledebouria cooperi are specifically used as an anti-inflammatory agent during circumcision ceremonies. The bulbs investigated were found to contain homoisoflavonoids, a class of compounds known to be specifically responsible for the anti-inflammatory properties of these plants when used by traditional healers. The bulbs of L. cooperi were found to contain two known homoisoflavonoids as well as a triterpenoid. Malic acid was also isolated from the methanol extract. A further homoisoflavonoid of the 3-benzyl-4-chromanone type was isolated from Scilla plumbea. Drimiopsis maculata was found to be an abundant source of natural products from which two scillascillin-type homoisoflavonoids as well as two aromatic compounds were isolated. Investigation into the fourth species, Drimia robusta, yielded an uncommon bufadienolide. As no spectroscopic information was available for this compound, the complete assignment of the compound was performed using 2-D NMR spectroscopy.
Extractives from the Meliaceae and Annonaceae.
(1997) Naidoo, Nesan.; Mulholland, Dulcie Aca.
Members of the Annonaceae and Meliaceae, two plant families which are distributed throughout the world, have been studied during the course of this work. The research is an account of the compounds isolated from six members of the Meliaceae (Australian, Indian and South African) and one from the Annonaceae (South African). These families have attracted special attention of scientists world-wide because of the compounds these plants produce and their medicinal applications. Extracts from these species are known to be widely used in traditional medicine and previous studies have demonstrated their anticancer, anti-microbial and other pharmacological activities. Limonoids and protolimonoids were isolated from the Indian Meliaceae specIes, Aphanamixis polystacha and from the South African Meliaceae species Turraea obtusifolia. Extractives from the seeds of Aphanamixis polystacha yielded seven limonoids (2-A to 2-G) from the hexane extract, while the methanol extract only yielded sucrose (2-H). Three of the limonoids (2-B, 2-E and 2-F) were novel and the stereochemistry of polystachin, compound (2-A), was revised. Extractives from Turraea obtusifolia yielded two triterpenoids (3-A and 3-B) and a limonoid (3-C) from the hexane extract of the seed. Several triterpenoids and a benzofuran compound were isolated from the Australian Meliaceae species, Dysoxylum pettigrewianum, Dysoxylum muelleri and Aglaia sapindina. Extractives from Dysoxylum pettigrewianum, yielded three triterpenoids (4-A to 4-C) from the hexane extract of the bark. Two of these triterpenoids (4-Band 4-C) were novel. Extractives from Dysoxylum muelleri yielded two triterpenoids (4-D and 4E) from the methylene chloride extract of the wood. Extractives from Aglaia sapindina yielded a benzofuran compound (4-F) from the hexane extract of the wood. This resulted in the revision of the structure of ferrugin (4-56). A flavonoid (5-A) was isolated from the aqueous extract of the seed of the South African Meliaceae Trichilia dregeana. A polyoxygenated cyclohexane epoxide (6-A) was isolated from the root and leaves of the Annonaceae species, Monanthotaxis caffia. The research undertaken involved the collection, extraction, isolation, purification and structural elucidation of these compounds by infrared, mass and nuclear magnetic resonance spectroscopic techniques.
Extractives from the Meliaceae and Icacinaceae.
(1990) Akerman, Leigh-Anne.; Mulholland, Dulcie Aca.; Pegel, Karl H.
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.
Extractives from the Meliaceae and Melianthaceae, and investigations into enamine chemistry.
(1997) Monkhe, Thabo Vincent.; Mulholland, Dulcie Aca.
Part A of this thesis is an account of the extractives isolated from one member of the Melianthaceae and two members of the Meliaceae. Plants belonging to these families are known to produce compounds with medicinal applications. Crude extracts from these plants are known to be widely used in traditional medicine. Structural elucidation was facilitated by the use of infrared, mass and nuclear magnetic resonance spectroscopic techniques. Three 20(29)-lupene type compounds (two known and one knew) were isolated from the bark of Bersama swinnyi (Melianthaceae); oleanolic acid was isolated from the leaves. The Meliaceae family is only represented b~ one species, Dysoxylum spectabile, in New Zealand. Two diterpenoids and two limonoids were isolated from the bark. The extracts of the rootbark and stembark of the hitherto uninvestigated species Turraea holstii (Gurke), supplied by Professor H. S. Rajab, Moi University, Kenya, were examined. Eight limonoids and a protolimonoid were isolated from the rootbark. A limonoid and a protolimonoid were isolated from the stembark. Some of the compounds isolated were found in both extracts. Four of the eight limonoids isolated were of the neotrichilenone type. The spectra for the compounds discussed in this text are presented in a separate book.
Extractives from the Meliaceae and Ptaeroxylaceae.
(2001) Naidoo, Dashnie.; Mulholland, Dulcie Aca.
This work is an account of the extractives from one member of the Meliaceae and one member of the Ptaeroxylaceae. In all, thirteen compounds have been isolated, of which four have not been described previously. Neobeguea mahafalensis belongs to the Neobeguea genus and has been classified into the Swietenieae subfamily of the Meliaceae. Neobeguea mahafalensis seeds obtained from Madagascar were investigated for the presence of limonoids. This is the first time extracts of the seeds were investigated. Previous work was done on the stem bark of this species. An andirobin-type limonoid, methyl angolensate (5), two mexicanolide-type limonoids, mexicanolide (6), khayasin (7), and three protolimonoids, sapelin E acetate (8), sapelin C (9) and grandifoliolenone (10), have been isolated in this work. One of these was novel. Cedrelopsis grevei belongs to the Cedrelopsis genus and has been classified into the Ptaeroxylaceae family. Extracts from the stem bark of Cedrelopsis grevei obtained from Madagascar yielded seven compounds, a triterpenoid, β-amyrin (15), a coumarin, scoparone (16), a limonoid, cedmiline (14), a triterpenoid derivative, cedashnine (17), a quassinoid, cedphiline (19), a lignan, cedpetine (18) as well as sitosteryl β-D-glucopyranoside (20). Three of these were novel.
Extractives from the Meliaceae and Simaroubaceae of Madagascar.
(2001) Coombes, Philip Hugh.; Mulholland, Dulcie Aca.
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.