AJOL: South African Journal of Botany: VOLUME 68 ISSUE 1 (2002)

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South African Journal of Botany

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VOLUME 68 ISSUE 1 (2002)

South African Journal of Botany 2002, 68: 1—13

A review of ethnobotanical research in southern Africa

B-E van Wyk

Department of Botany, Rand Afrikaans University, PO Box 524, Auckland Park 2006, Johannesburg, South Africa

e-mail: [email protected]

Received 15 August 2001, accepted in revised form 29 January 2002

The diversity of plant species in southern Africa is matched by an equally rich cultural diversity, but traditional uses of plants have not yet been systematically recorded. Available information is fragmentary and widely dispersed in many different journals and books. A survey by Liengme (1983a) has shown several gaps in the scientific literature and some progress has been made towards a more complete record of indigenous plant use in the region. Information on some ethnic groups, such as the Khoi, Ndebele and Swazi, as well as the interaction between plants and people, folk taxonomies, plant-related mythology, ethnoveterinary medicine and pre-colonial plant use are some of the aspects that still remain poorly recorded. In contrast, ethnopharmacology – particularly the testing of biological activity of crude extracts and isolated compounds – has received considerable attention in recent years. The aim of these studies is usually to validate traditional uses rather than to provide information for product development. A review of the literature on various categories of plant use, including recent publications and some hitherto unpublished research, is presented. Ethnobotany remains an underdeveloped discipline in southern Africa and there is an urgent need to systematically document indigenous knowledge on traditional plant use before it becomes irretrievably lost to future generations.

South African Journal of Botany 2002, 68: 14—20

The sausage tree (Kigelia pinnata): ethnobotany and recent scientific work

PJ Houghton
Pharmacognosy Research Laboratories, Department of Pharmacy, King's College London, 150 Stamford Street, London SE1 9NN, United Kingdom

e-mail: [email protected]

Received 30 July 2001, accepted in revised form 2 October 2001

Kigelia pinnata (Bignoniaceae), colloquially called the Sausage Tree, or Worsboom, on account of its large fruits, has a variety of medicinal uses throughout Africa where it grows as an endemic species in many areas. Chemical examination has resulted in the isolation of iridoids and naphthoquinoids as important secondary metabolites but flavonoids and lignans have also been isolated. Investigation into the biological activity of K. pinnata has focussed on its antibacterial activity and its cytotoxic effects against cancer cell lines. These are related to the traditional uses of bark and fruit extracts for treating diseases caused by micro-organisms and as a remedy for skin cancer. The iridoids and naphthoquinones have been shown to display antibacterial activity and also the ability to inhibit the growth of yeasts. Considerable in vitro cytotoxicity has been demonstrated by extracts of the fruits and barks and the iridoid-related compound norviburtinal and the naphthoquinone isopinnatal have been shown to be two of the compounds responsible. Although little ethnopharmacological evidence exists, the naphthoquinones are active against several protozoal species associated with disease. The compounds also show cytotoxicity against mammalian cell lines. More research is needed to investigate further the reputed effects on the skin of extracts of this plant.

South African Journal of Botany 2002, 68: 21—30

The status of bark in South African traditional health care

OM Grace¹, HDV Prendergast², J van Staden¹* and AK Jäger¹
^{1 Research Centre for Plant Growth and Development, School of Botany and Zoology, University of Natal Pietermaritzburg, Private Bag X01 Scottsville 3209, South Africa
^{2 Centre for Economic Botany, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AE, United Kingdom
* Corresponding author, email: [email protected]}}

Received 22 October 2001, accepted in revised form 2 November 2001

Bark products constitute nearly one third of plant material used in South African traditional medicine. Since the large majority of South Africans make use of traditional health care, bark is fundamental to the traditional pharmacopoeia. In this review we consider the status of bark resources, as reflected by the literature, and highlight the need for multi-disciplinary research to address the lack of available information on plant species used for their bark. The supply of bark to the medicinal plant trade has been rendered non-sustainable, due to increased user populations and reduced indigenous vegetation. Whilst conservation of the South African flora is paramount, natural resources cannot meet the current, nor foreseeable, demand for bark. Alternatives such as tree propagation and cultivation, strategic management and plant part substitution are discussed. Effective implementation of these action plans is reliant on the dissemination of existing and new knowledge. The prevailing scenario of a non-sustainable bark supply has impacted negatively on the quality of bark products available to the consumer, as problems of incorrect identification and purposeful adulteration arise. To facilitate monitoring and standardisation, phytochemical references should be established for bark authentication, and used in conjunction with morphological and anatomical characters for identification in the case of unknown specimens. The importance of bark in South African traditional health care warrants attention from all research sectors to conserve the country’s rich floral heritage, and the integrity of traditional health care.

South African Journal of Botany 2002, 68: 31—35

Isolation of b -asarone, an antibacterial and anthelmintic compound, from Acorus calamus in South Africa

LJ McGaw, AK Jäger and J van Staden*
Research Centre for Plant Growth and Development, School of Botany and Zoology, University of Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa

* Corresponding author, e-mail: [email protected]

Received 30 November 2000, accepted in revised form 8 March 2001

The aromatic rhizomes of Acorus calamus L. are used extensively in traditional medicine worldwide. They reportedly relieve stomach cramps, dysentery and asthma, and are used as anthelmintics, insecticides, tonics and stimulants. Alcoholic rhizome extracts of A. calamus growing in KwaZulu-Natal, South Africa, were previously found to have anthelmintic and antibacterial activity. Using bioassay-guided fractionation, the phenylpropanoid b-asarone was isolated from the rhizome. This compound was shown to possess anthelmintic and antibacterial activity. It has previously been isolated from A. calamus, and a related species, A. gramineus. Different varieties of A. calamus exhibit different levels of b-asarone, with the diploid variety containing none of the compound. Mammalian toxicity and carcinogenicity of asarones has been demonstrated by other researchers, supporting the discouragement of the medicinal use of Acorus calamus by traditional healers in South Africa.

South African Journal of Botany 2002, 68: 36—40

Lectin-like proteins from South African plants used in traditional medicine

M Gaidamashvili¹ and J van Staden*
Research Centre for Plant Growth and Development, School of Botany and Zoology, University of Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, Republic of South Africa
^{1 Present address: Department of Plant Physiology, State University of Tbilisi, 380028, Republic of Georgia
* Corresponding author, e-mail: [email protected]}

Received 4 December 2000, accepted in revised form 9 April 2001

Seventeen indigenous South African plants used in traditional medicine were screened for lectin-like proteins. Plant agglutinins were isolated and partially purified from different parts of fresh and dry plant material. Hemagglutinating activity towards fresh and glutaraldehyde-treated rabbit erythrocytes was detected in thirteen species. Sixteen sugars were analysed for carbohydrate-binding specificity of agglutinins. Hemagglutinating activity was mostly inhibited by melibiose and trehalose. Relatively few inhibitions were detected with monosaccharides. The present study indicates several new hemagglutinins from indigenous plant species of South Africa used in traditional medicine. A description of some of the conditions for their detection and partial purification is given. The possible contribution of lectin-like proteins in the pharmacological effects observed for medicinal plants is indicated.

South African Journal of Botany 2002, 68: 41—46

Variation in antibacterial activity of Schotia species

LJ McGaw, AK Jäger and J van Staden*
Research Centre for Plant Growth and Development, School of Botany and Zoology, University of Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa

* Corresponding author, e-mail: [email protected]

Received 29 March 2001, accepted in revised form 7 June 2001

The roots and bark of Schotia brachypetala are used in South African traditional medicine as a remedy for dysentery and diarrhoea. The paucity of pharmacological and chemical data on this plant prompted an investigation into its antibacterial activity. The differences in activity of ethanol and water extracts with respect to plant part, season and geographical position were analysed. No extreme fluctuations in activity were noted. Two other Schotia species, S. afra and S. capitata, were included in the study, and both displayed good in vitro antibacterial activity. The storage of the plant, either as dried, ground plant material at room temperature, or as an extract residue at -15°C, had little effect on the antibacterial activity. In general, the ethanolic extracts were more active than the aqueous extracts. The chemical profiles on TLC chromatograms were compared and found to be very similar in the case of ethanol extracts prepared in different months of the year, and from different trees. The extracts of the three species and of the leaves stored under various conditions also showed similar TLC fingerprints, however, various plant parts of S. brachypetala showed distinctly different chemical compositions.

South African Journal of Botany 2002, 68: 47—50

Cyclooxygenase inhibitory activity of Aloe species

KL Lindsey¹*, AK Jäger¹ and AM Viljoen²
^{1 Research Centre for Plant Growth and Development, School of Botany and Zoology, University of Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa
^{2 Department of Pharmacy and Pharmacology, University of the Witwatersrand, Faculty of Health Sciences, 7 York Road, Park Town 2193, South Africa
* Corresponding author, e-mail: [email protected]}}

Received 7 February 2001, accepted in revised form 26 July 2001

Aloes are used in traditional medicine for arthritis and to treat skin irritations. These indications could point to the plants having anti-inflammatory activity. Methanolic extracts of dried leaves of 53 Aloe species were tested in the cyclooxygenase-1 assay. Cyclooxygenase is one of the key enzymes in the biosynthesis of prostaglandins that are implicated in inflammatory processes. The selected species are representative of all chemotypes identified for the genus. The grass-like and scandent aloes accumulate flavonoids in co-occurrence with the anthrone isomers aloin A and B (A. boylei). This group is considered to be basal in Aloe and with the exception of A. ciliaris, members of this chemotype showed high values of inhibition. The flavanone producing species (A. pratensis, A. humilis and A. pretoriensis) also exhibited high values. These high values are similar to those recorded for aloes which accumulate anthrones and chromones (A. wickensii). The two main anthrone chemotypes in Aloe are represented by homonataloin- and aloin accumulating species. No significant differences could be observed between species accumulating aloin (A. ferox) when compared to the homonataloin-producing species (A. mitriformis). It is interesting to note that species with similar exudate profiles (A. mitriformis and A. comptonii) showed similar values of inhibition.

South African Journal of Botany 2002, 68: 51—54

Some medicinal properties of Cussonia and Schefflera species used in traditional medicine

P Tetyana¹, EA Prozesky², AK Jäger¹, JJM Meyer² and J van Staden¹*
^{1 Research Centre for Plant Growth and Development, School of Botany and Zoology, University of Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa
^{2 Department of Botany, University of Pretoria, Pretoria 0002, South Africa
* Corresponding author, email: [email protected]}}

Received 27 January 2001, accepted in revised form 31 July 2001

Ethanolic and ethyl acetate extracts of Cussonia spicata, C. paniculata and Schefflera umbellifera were screened for anti-bacterial, anti-malarial and anti-inflammatory activities. Root and bark extracts of C. spicata showed anti-bacterial activity against Staphylococcus aureus in the disc-diffusion assay. All species inhibited cyclooxygenase in the cyclooxygenase-1 assay. S. umbellifera ethanolic and ethyl acetate extracts inhibited Plasmodium falciparum, a malaria-causing agent, in an in vitro assay. The results obtained rationalised the use of the three selected species of Araliaceae for specific types of diseases in traditional medicine.

South African Journal of Botany 2002, 68: 55—61

Investigation of the biological activities of Siphonochilus aethiopicus and the effect of seasonal senescence

ME Light¹, LJ McGaw¹, T Rabe¹, SG Sparg¹, MB Taylor², DG Erasmus², AK Jäger¹ and J van Staden¹*
^{1 Research Centre for Plant Growth and Development, School of Botany and Zoology, University of Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa
^{2 Department of Medical Virology, Institute of Pathology, University of Pretoria, PO Box 2034, Pretoria 0001, South Africa
* Corresponding author, e-mail: [email protected]}}

Received 2 February 2001, accepted in revised form 3 September 2001

Siphonochilus aethiopicus (Schweinf.) B.L. Burtt (Zingiberaceae), commonly known as wild ginger, is one of the most important and threatened medicinal plants in South Africa. A study of the pharmacological properties of S. aethiopicus and the effect of seasonal senescence on antibacterial and anti-inflammatory properties was undertaken. Water, ethanol and ethyl acetate extracts were prepared from the leaves, rhizomes and roots of S. aethiopicus plants. The extracts were tested in a variety of pharmacological assays. Results for the general screening showed antibacterial and anti-inflammatory activity. Some cytotoxicity was observed with the aqueous extracts of the rhizome. However, no significant activity against the herpes simplex virus types 1 and 2, the influenza A virus, and in the anthelmintic, antischistosomal and biochemical induction assays were observed. In the microdilution antibacterial assay, no inhibitory activity against the test bacteria was detected with the aqueous extracts. The ethanol and ethyl acetate extracts tested showed greater antibacterial activity at minimal inhibitory concentrations ranging from 0.78 to 3.13mg ml-1 against the Gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus) than the Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae). Little difference was observed between the ethanol and ethyl acetate extracts, or between the different plant parts. Ethanol extracts were prepared from the different plant parts before and after seasonal senescence, and tested for antibacterial and anti-inflammatory activity. There appeared to be a loss of antibacterial activity in the leaves with senescence, concomitant with an increase of activity in the alpha-roots. In the cyclooxygenase-1 assay, the aqueous extracts showed no significant prostaglandin synthesis inhibition. For the ethanol and ethyl acetate extracts, the leaves showed the highest levels of activity at a concentration of 250µg ml-1 per test solution, in both the cyclooxygenase-1 and -2 assays. Some differences in the levels of anti-inflammatory activity in the roots following senescence were also observed. There was a slight loss of activity as a result of drying the rhizome material prior to extraction. This suggests that fresh rhizome material may be more effective for medicinal use, although it should be noted that the aqueous rhizome extracts displayed moderately high levels of cytotoxicity, and may require further investigation.

South African Journal of Botany 2002, 68: 62—67

Extraction of antibacterial compounds from Combretum microphyllum (Combretaceae)

M Kotzé and JN Eloff*
Department of Pharmacology, University of Pretoria, Pretoria, South Africa

*Corresponding author, e-mail: [email protected]

Received 11 June 2001, accepted in revised form 8 October 2001

The aim of this investigation was to simplify extracts to facilitate the isolation of antibacterial compounds from the complex mixture of chemicals in the plant by using different extractants. Intact dried leaves were extracted with acetone and 1% aqueous sodium bicarbonate and ground leaves were extracted by hexane, carbon tetrachloride, di-isopropylether, ethyl ether, methylene dichloride, tetrahydrofuran, acetone, ethanol, ethyl acetate, methanol and water. TLC was used to determine chemical composition and antibacterial activity of extracts was determined by a microplate serial dilution method. The different solvents extracted from 2.6 to 17.4% of the dry weight. Methanol, methylene dichloride and tetrahydrofuran extracted the most components. The chemical composition of the non-polar components of the different extracts were remarkably similar. The minimum inhibitory concentration for the different extractants varied from 0.01 to 1.25mg/ml with the four test organisms used (Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Enterococcus faecalis). The extracts had similar activity towards Gram-negative and Gram-positive bacteria. Di-isopropyl ether, ethanol, ethyl ether, acetone and ethyl acetate extracted high antibacterial activity with a lower quantity of other non-active compounds and could be useful for isolating bioactive compounds.

South African Journal of Botany 2002, 68: 68—71

Coupling SFE to uterotonic bioassay: an on-line investigation of the uterotonic activity of compounds from Grewia occidentalis (Tiliaceae)

DA Mulholland¹*, V Sewram¹, M Raynor¹, K Thornell¹ and DM Raidoo²
^{1 Natural Products Research Group, School of Pure and Applied Chemistry, University of Natal, Durban 4041, South Africa
^{2 Department of Clinical and Experimental Pharmacology, University of Natal Medical School, Private Bag 7, Congella 4013, South Africa
* Corresponding author, e mail: [email protected]}}

Received 14 August 2001, accepted in revised form 22 October 2001

Grewia occidentalis L. (Tiliaceae) is a scrambling shrub or small tree sometimes used as a decorative garden plant. The plant is used for a wide range of medicinal and magical purposes, including the facilitation of childbirth. Aqueous and supercritical fluid extracts of the wood were shown to cause guinea pig uterine muscle contraction. The active compounds were identified as oleanonic acid and coniferaldehyde ((E)-4-hydroxy-3-methoxycinnamaldehyde).

South African Journal of Botany 2002, 68: 72—76

In vitro antifungal activity of some South African medicinal plants

AJ Afolayan*, DS Grierson, L Kambizi, I Madamombe and PJ Masika
Department of Botany, Faculty of Science & Technology, University of Fort Hare, Alice 5700, South Africa

* Corresponding author, e-mail: [email protected]

Received 6 August 2001, accepted in revised form 22 October 2001

The acetone extracts of 12 plants used in folkloric medicine in the Eastern Cape of South Africa, were investigated for their in vitro antimycotic activity against five fungi using the agar dilution method. The extracts showed significant inhibition of growth of the test organisms at varying concentrations. Extracts from Arctotis arctotoides showed the highest activity at concentrations varying from 0.1 to 10mg ml-1, followed by Usnea barbata, a lichen, while Grewia occidentalis demonstrated the least activity. Extracts from A. arctotoides, U. barbata, Combretum caffrum, Aloe ferox, Salix capensis, Schotia latifolia and Prunus persica were fungicidal at 10mg ml-1 which was the highest concentration tested. The fungi differed significantly in their susceptibility to plant extracts with Alternaria alternaria, and Mucor hiemalis, being completely inhibited at 5 and 10mg ml-1 by most of the extracts.

South African Journal of Botany 2002, 68: 77—79

A phytochemical investigation of Craterocapsa tarsodes, a plant used for the treatment of epilepsy by the Northern Sotho people of South Africa

FR van Heerden¹*, AM Viljoen² and SP Mohoto²
^{1 Department of Chemistry and Biochemistry, Rand Afrikaans University, PO Box 524, Auckland Park 2006, South Africa
^{2 Department of Pharmacy and Pharmacology, University of the Witwatersrand, Faculty of Health Sciences, 7 York Road, Parktown 2193, South Africa
* Corresponding author, e-mail: [email protected]}}

Received 8 August 2001, accepted in revised form 22 October 2001

Craterocapsa tarsodes (Campanulaceae) is one of the plants used by the Northern Sotho people in an herbal remedy to treat epilepsy. A phytochemical investigation of this plant resulted in the isolation of three major secondary metabolites. By using NMR spectroscopy and MS spectrometry these three compounds were identified as the known acteoside (verbascoside), pinocembrin 7-b-neohesperidoside and shanzhiside methyl ester. A literature search revealed that neurosedative properties are associated with acteoside and that flavonoids related to pinocembrin interact with benzodiazepine receptors. Therefore, the presence of acteoside and pinocembrin neohesperidoside in C. tarsodes may account for the use of this plant against epilepsy.

South African Journal of Botany 2002, 68: 80—85

COX-1 and COX-2 inhibitory activity in extracts prepared from Eucomis species, with further reference to extracts from E. autumnalis autumnalis

JLS Taylor and J van Staden*
Research Centre for Plant Growth and Development, School of Botany and Zoology, University of Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa

* Corresponding author, e-mail: [email protected]

Received 7 August 2001, accepted in revised form 23 October 2001

Prostaglandins are important mediators of the body’s response to pain and inflammation, and are formed from essential fatty acids found in cell membranes. This reaction is catalysed by cyclooxygenase, a membrane-associated enzyme occurring in two isoforms, COX-1 and COX-2. Non-steroidal anti-inflammatory drugs (NSAIDs) act by inhibiting the activity of COX. The investigation of Eucomis species (a popular South African medicinal plant) for potential anti-inflammatory activity showed high levels of COX-1 and -2 inhibitory activity associated with several species, specifically E. autumnalis and E. humilis. Further investigation was conducted using E. autumnalis subspecies autumnalis, as this is the species that is most widely utilised by traditional healers in southern Africa. The bulb extracts from this species were characterised by higher IC50 values for both COX-1 and COX-2 inhibition than obtained for the leaf and root extracts. The ratio of COX-2/COX-1 inhibitory activity was, however, similar to that of the root extracts, both values being less than one. The leaf extracts showed higher COX-1 than COX-2 inhibitory activity, with a ratio of 1.9. Most traditional remedies utilising Eucomis, are prepared from the bulbs (possibly including some root material) of this species.

South African Journal of Botany 2002, 68: 86—89

Bulb alkaloids of the reputedly psychoactive Brunsvigia radulosa (Amaryllidaceae)

NR Crouch*^1,2, J Chetty², DA Mulholland² and E Ndlovu^2,3
^{1 Ethnobotany Unit, National Botanical Institute, PO Box 52099, Berea Road, Durban 4007, South Africa
^{2 Natural Products Research Group, Department of Chemistry, University of Natal, Durban 4041, South Africa
^{3 Kwamalulekoes Nursery and Herbalist, PO Box 11409, Mooi River 3300, South Africa
* Corresponding author, e-mail: [email protected]}}}

Received 8 August 2001, accepted in revised form 23 October 2001

Brunsvigia radulosa Herb. is a bulbous ethnomedicinal herb, widespread from the Great Karoo northwards through the grasslands of southern Africa. Earlier workers have previously identified a total of ten isoquinoline alkaloids from this taxon, including 1-O-acetylnorpluviine which is only known from B. radulosa. The current report investigates the suggestions of earlier workers relating to the psychoactivity of the bulb constituents, and its usefulness in the traditional treatment of cancer. The identification of anhydrolycorinium chloride, the second ever isolation of this compound from a plant, supports earlier observations for antineoplastic activity of bulb and leaf extracts of B. radulosa in a mouse P-388 lymphocytic leukaemia system. In the current study, 1-O-acetyllcorine was also isolated from the bulbs.

South African Journal of Botany 2002, 68: 90—93

In vitro inhibition of drug-resistant and drug-sensitive strains of Mycobacterium tuberculosis by Helichrysum caespititium

JJM Meyer*, N Lall and ADM Mathekga
Department of Botany, University of Pretoria, Pretoria 0002, South Africa

* Corresponding author, e-mail: [email protected]

Received 30 July 2001, accepted in revised form 24 October 2001

Antimycobacterial activity of acetone and water extracts of Helichrysum caespititium against a drug-sensitive strain of Mycobacterium tuberculosis was evaluated by the agar plate method. The acetone extract exhibited inhibitory activity at a concentration of 0.5mg ml-1 against this strain whereas the organism was found to be partially susceptible to the water extract at 5.0mg ml-1. The inhibitory activity of the acetone extract was confirmed using the rapid radiometric method and the minimum inhibitory concentration (MIC) was found to be 0.1mg ml-1. Caespitate, a novel phloroglucinol, which was previously isolated and identified, from H. caespititium was also evaluated for its activity against drug-sensitive and drug-resistant strains of M. tuberculosis. The MIC of caespitate was found to be 0.1mg/ml for all the M. tuberculosis strains. The ability of caespitate to inhibit the growth of all the strains of M. tuberculosis, shows the broad spectrum antimycobacterial activity of the compound.

South African Journal of Botany 2002, 68: 94—99

The Bio-diversity of traditional vegetables of the Transkei region in the Eastern Cape of South Africa

RB Bhat* and T Rubuluza
Department of Botany, University of Transkei, Umtata 5099, South Africa

* Corresponding author, e-mail: [email protected]

Received 13 August 2001, accepted in revised form 2 November 2001

The primary concern of this investigation was to study the marginal utilisation of inexpensive indigenous plants that are not normally cultivated or used for commercial purposes. The present investigation recorded the uses of 36 wild vegetables (‘imifino’) in the predominantly Xhosa occupied Eastern Cape (South Africa). The importance of these under-exploited wild vegetables cannot be overestimated.

South African Journal of Botany 2002, 68: 100—105

The composition and antimicrobial activity of the essential oil of the resurrection plant Myrothamnus flabellifolius

AM Viljoen¹*, ME Klepser², EJ Ernst³, D Keele³, E Roling³, S van Vuuren¹, B Demirci⁴, KHC BaSer⁴ and B-E van Wyk⁵
^{1 Department of Pharmacy and Pharmacology, University of the Witwatersrand, 7 York Road, Parktown 2193, South Africa
^{2 College of Pharmacy, Ferris State University, Borgess Medical Center Department of Pharmacy, Kalamazoo, Michigan 49001, USA
^{3 College of Pharmacy, The University of Iowa, Iowa City, Iowa 52242, USA
^{4 Medicinal and Aromatic Plant and Drug Research Center (TBAM), Anadolu University, 26470 EskiSehir, Turkey
^{5 Department of Botany, Rand Afrikaans University, PO Box 524, Auckland Park 2006, Johannesburg, South Africa
* Corresponding author, e-mail: [email protected]}}}}}

Received 30 July 2001, accepted in revised form 6 November 2001

An investigation of the antibacterial and antifungal activity of Myrothamnus flabellifolius against eleven different pathogens showed inhibition of all micro-organisms except for Salmonella typhimurium and Alternaria alternata. A preliminary screening was done by the disc diffusion method and three susceptible organisms were selected to demonstrate the rapid onset of antimicrobial activity using time-kill methodology. Essential oil concentrations, ranging from 0.0625% to 2%, exhibited strong fungicidal activity against Candida albicans and were found to be bacteriostatic against Staphylococcus aureus with microbiocidal effects increasing in a concentration-dependant manner. Essential oil rapidly reduced viable counts of Pseudomonas aeruginosa but regrowth was noted after 24 hours. The results have been generated in duplicate in two separate microbiology laboratories using different time-kill methods and the results are in agreement. Eighty-five compounds were identified by GC-MS in the hydro-distilled essential oils which contained pinocarvone and trans-pinocarveol as the major terpenoids. The antimicrobial properties of the essential oil are presented as a possible rationale for the traditional use of the resurrection bush, Myrothamnus flabellifolius in African herbal medicinal preparations.

South African Journal of Botany 2002, 68: 106—110

In vitro activity of Aloe extracts against Plasmodium falciparum

RL van Zyl* and AM Viljoen
Department of Pharmacy and Pharmacology, University of the Witwatersrand, Faculty of Health Sciences, 7 York Road, Parktown 2193, South Africa

* Corresponding author, email: [email protected]

Received 5 September 2001, accepted in revised form 6 November 2001

The antiplasmodial activity and toxicity data of 34 Aloe species and their main constituents were determined. A number of the methanol extracts possessed antimalarial activity where 50% of the parasite growth was inhibited (IC50 value) by 32 to 77µg ml-1 of the extract. The chemical common to the most active species is the anthrone C-glucoside homonataloin which inhibited the chloroquine-resistant Plasmodium falciparum strain with an IC50 value of 13.46 ± 1.36µg ml-1. Homonataloin was a more potent inhibitor of parasite growth than aloin (IC50 value of 107.20 ± 4.14µg ml-1). The Aloe extracts tested did not exhibit any toxicity towards transformed human kidney epithelium cells at the concentrations (0.5—50µg ml-1) used in the antimalarial assay.

South African Journal of Botany 2002, 68: 111—114

Organ-to-organ and seasonal variations of alkaloids from Crinum moorei

EE Elgorashi¹, SE Drewes² and J van Staden¹*
^{1 Research Centre for Plant Growth and Development, School of Botany and Zoology, University of Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa
^{2 School of Chemical and Physical Sciences, University of Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa
* Corresponding author, e-mail: [email protected]}}

Received 21 August 2001, accepted in revised form 26 October 2001

Dilute HCl extraction followed by gas chromatography were used to determine the distribution and seasonal variation of alkaloids in Crinum moorei. Significant organ-to-organ variations were detected for the individual alkaloids crinine, lycorine, powelline, undulatine, crinamidine, 1-O-acetyllycorine, 1-epideacetylbowdensine and 3-O-acetylhamayne. Alkaloids which showed significant seasonal variations were lycorine, crinine and undulatine.

South African Journal of Botany 2002, 68: 115—116

The essential oil composition of the roots and rhizomes of Siphonochilus aethiopicus

AM Viljoen¹*, B Demirci², KHC BaSer² and B-E van Wyk³
^{1 Department of Pharmacy and Pharmacology, University of the Witwatersrand, Faculty of Health Sciences, 7 York Road, Parktown 2193, South Africa
^{2 Medicinal and Aromatic Plant and Drug Research Center (TBAM), Anadolu University. 26470-EskiSehir, Turkey
^{3 Department of Botany, Rand Afrikaans University, PO Box 524, Auckland Park 2006, Johannesburg, South Africa
* Corresponding author, e-mail: [email protected]}}}

Received 7 September 2001, accepted in revised form 6 November 2001

The composition of the essential oil obtained through hydrodistillation is reported for the roots and rhizomes of Siphonochilus aethiopicus. The major compounds in both the roots and the rhizomes are 1,8-cineole, (E)-b-ocimene, cis-alloocimene, together with the recently reported furanoterpenoid (4aa,5b,8a)-3,5,8a-trimethyl-4,4a,9-tetrahydo-naphtho[2,3-b]-furan-8(5H)-one which is the major compound in both plant organs. The roots and rhizomes are virtually identical in composition and provide a chemical rationale to promote plant part substitution as a method to conserve this endangered South African medicinal plant.

South African Journal of Botany 2002, 68: 117

Tibetan Medicinal Plants

Edited by Christa Kletter and Monika Kriechbaum

2001 Medpharm Scientific Publishers, Stuttgart

51 tables, 46 figures and 415 colour photographs, 383 pages. Hardcover

ISBN 3—88763—067—X; ISBN 0—8493—0031—2, Price: Euro 138

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VOLUME 68 ISSUE 1 (2002)

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South African Journal of Botany