International Organization for Chemical Sciences in Development IOCD Working Group on Chemistry v______J

CHEMISTRY, BIOLOGICAL AND PHARMACOLOGICAL PROPERTIES OF AFRICAN MEDICINAL

Proceedings of the first International IOCD-Symposium Victoria Falls, Zimbabwe, February 25-28, 1996

Edited by

K. HOSTETTMANN, F. CHINYANGANYA, M. MAIL LARD and J.-L. WOLFENDER

UNIVERSITY OF ZIMBABWE PUBLICATIONS INTERNATIONAL ORGANIZATION FOR CHEMICAL SCIENCES IN DEVELOPMENT

WORKING GROUP ON PLANT CHEMISTRY

CHEMISTRY, BIOLOGICAL AND PHARMACOLOGICAL PROPERTIES OF AFRICAN MEDICINAL PLANTS

Proceedings of the First International IOCD-Symposium Victoria Falls, Zimbabwe, February 25-28, 1996

Edited by

K. HOSTETTMANN, F. CHINYANGANYA, M. MAILLARD and J.-L. WOLFENDER

Institut de Pharmacognosie el Phytochimie. Universite de Ixtusanne. HEP. CH-1015 Lausanne, Switzerland and Department of Pharmacy. University of Zimbabwe. P.O. BoxM.P. 167. Harare. Zimbabwe

UNIVERSITY OF ZIMBABWE PUBLICATIONS 1996 First published in 1996 by University of Zimbabwe Publications P.O. Box MP 203 Mount Pleasant Harare Zimbabwe

ISBN 0-908307-59-4

Cover photos. African traditional healer and Harpagophytum procumbens (Pedaliaceae) © K. Hostettmann

Printed by Mazongororo Paper Converters Pvt. Ltd., Harare Contents

13. Research, development and production ofplant-based medicines in Africa. Example of Rwanda 2 2 1 L. Van Puyvelde 14. Production of traditional medicine: preparations accepted as medicines in Mali 235 D. Diallo, B.S. Paulsen and B. Hvemm 15. Bioactive metabolites from African medicinal plants 243 C. Spatafora and C. Tringali 16. Polyphenolic constituents of Brackenridgea zanguebarica () and their biological activities 253 A. Marston, J.D. Msonthi and K. Hostettmann 17. Constituents of muthi plants of Southern Africa: magical and mol luscicidal properties 261 S. E. Drewes, M. Horn, B.M. Sehlapelo, L. Kayonga, C.C. Appleton. T. Clark and T. Brackenbury 18. Unusual metabolites from Tanzanian annonaceous plants: the Uvaria 267 M. H.H. Nkunya 19. Quantitative and qualitative analysis of the saponins from berries of cultivated Phytolacca dodecandru by LC/UV and LC/MS 283 S. Rodriguez, J.-L. Wolfender, J.D. Msonthi and K. Hostettmann 20. Isolation and characterization of two saponins from Becium grandiflorum \w.obovatum 295 l. Burger, C.F. Albrecht, H.S.C. Spies and B.V. Burger 21. Hypoxoside: a putative, non-toxic prodrug for the possible treatment of certain malignancies, HIV-infection and inflammatory conditions 303 C.F. Albrecht 22. Antimalarial active principles of Spathodea campanulata 309 O. O.G. Amusan, E.K. Adesogan and J.M. Makinde 23. Antimalarial activity of Artemisia afra against Plasmodium falciparum in vitro 315 M. A. Abrahams, B.M. Sehlapelo, W.E. Campbell, D.W. Gammon, P. J. Smith and P.l. Folb

24. Efficacy and duration of activity of Lippia javanica Spreng, Ocimum canum SlMS and a commercial repellent against Aedes 3 2 1 aegypti N. Lukwa, C. Masedza, N.Z. Nyazema, C.F. Curtis and G.L. Mwaiko Index 327 17. Constituents of muthi plants of Southern Africa: magical and molluscicidal properties

S.E. D r ew es1, M. H o r n 1, B.M. S eh lapelo 1, L. K a y o n g a 1, C.C. A ppleto n2, T. Cla r k 1 and T. B rack enbury2

1Department of Chemistry and Chemical Technology, University of Natal, Pietermaritzburg 3209, South Africa and 2Department of Zoology and Entomology, University of Natal, Pietermaritzburg 3209, South Africa

Introduction

Southern Africa has a variety of muthi plants which are used for magical and other purposes. The focus in this contribution is on four such plants, namely, Brackenridgea zanguebarica, Cassipourea gerrardii, Hypoxis hemerocallidea (formerly rooperi) and Ocotea bullata. Finally there is a contribution on a muthi tree which has potential as a Third World molluscicide. Apodytes dimidiata.

Results and discussion

The small tree Brackenridgea zanguebarica (Ochnaceae; see also chapter 16), which grows in the Northern Province of South Africa and Zambia, has a bright yellow bark. Various magical powers are ascribed to it by indigenous Venda people who call it “mutavhatsindi", It is supposed to protect from lightning strikes and also no adult may dig up the roots of the tree as this can lead to sterility. From the bark two new compounds (1, 2) were isolated and fully characterized (Drewes and Hudson 1984, Drewes etal. 1987). 262 S.E. Drewes, M. Horn, H.M. Sehlapelo, L, Kayonga, C.C Appleton, T. Clark and T.Brackenbury

These are a dimeric dihydrochalcone (1) and a dimeric chalcone (2). Other compounds were present in lower concentration.

The tree known as onionwood. Cassipourea gerrardii (Macarisiae), is believed to have many magical properties but it is used as a skin lightener, particularly by the indigenous people of Kwazulu-Natal. The finely ground bark is mixed with sodium carbonate and milk and then applicd-as a face-pack by young maidens. Since hydroquinone was used in commercial preparations of skin lighteners (now no longer on the market) and since Cassipourea was known to contain phenolic compounds, this investigation was undertaken. The related plant C. gummijlua (“unu/onga") was also examined. Both plants contained novel dimeric A-type proanthocyanidins (Drewes el al. 1992, Drewes and Taylor 1994). The structures (3 and 4) arc shown below.

(3) R = H

(4) R = CH,

The compound 4. obtained from C. Gummijlua undergoes tin interesting rearrangement, which involves a hydroquinone intermediate, when treated with NaHCOi.

The commonly occurring bulbous plant (Kwazulu-Natal) Hxpoxis rooperi (now hemerocallidea) has certain magical properties but is also used mainly for treating urinary ailments (Drewes and Liebenberg 1982. Marini-Bettolo et al. 1982. Drewes el al. 1984). Our initial investigation was prompted by the observations of a representative of a pharmaceutical company that it cured certain cancers. From the plant we obtained as major product, the new compound (5), named hypoxoside by Marini-Bettolo (Marini-Bettolo el al. 1982). Hydrolysis of compound 5 with P-glucosidase leads to the aglycone which we named rooperol. In this form the compound certainly inhibits the growths of certain cancer cells. The tests carried out on rooperol form the basis of chapter 2 I. Constituents ofm uthi plants of Southern Africa: magical and molluscicidal properties 263

OH .()—Glucose

Glucose—0 II (5)

The black stink wood (Ocolca bullaia: Lauraceac) which occurs in the Eastern Cape Province and Kwa/ulu-Natal is one of the top-selling “muthi" plants. Reserves arc now very low and the tree is specially protected by Government Ordinance. The bark is used by traditional healers to cure headaches, but its main use relates to its magical powers. It is a favorite love potion and it is alleged to promote a wide variety of magical effects. Our interest here was twofold: i) to establish the structure of the main constituents in the bark ii) to examine the chemical relationship between Ocolca bark and Cryptocarya bark (also belonging to the Lauraceac family). This was particularly important as the scarcity of Ocolca bark has led to the use (by traditional healers) of Cryptocarya bark as substitute.

The bark of (). bullaia gave as major product the neolignan 6 which we have named ocobullcnone (Sehlapelo cl at. 1993).

H,C'<

( 6 )

From four Cryptocarya species we were able to isolate a variety of new cx- pyrones, for example cryptofolione (7). but no ocobullcnone. (Drewes el al. 1995). o

( 7 ) 264 S.E. Drewes, M. Horn, B.M. Sehlapelo, L Kayonga, C.C Appleton, T. Clark and T.Brackenbury

In one species of Cryptocarya, C. liehertiana, growing in the northern part of South Africa and in Zimbabwe, we were however, finally able to demonstrate that ocobullenone also occurred, thus supplying the “missing link”.

Molluscicides

From Apodytes dimidiala (Icacinaccac) the iridoid gcnipin (8) and its 10-acetyl derivatives (9) were isolated (Drewes. S.E.', Kayonga, L., Appleton. C.C., Clark, T.. and Brackenbury, T., Journal of Natural Products, in press). These two compounds were shown to have molluscicidal properties as shown by tests on liulinns africanits the intermediate host of Schistosoma haematobium. Results are shown below:

OH OCOCH, Gcnipin (8) Genipin acetate (9) LDso 25.27 ppm LDso 21.72 ppm LDno 32.57 ppm LD9() 39.40 ppm

The use of this plant as a Third World molluscicide is being investigated.

Acknowledgments

Thanks are due to the University Research Fund for financial assistance.

References

Drewes, S.E. and Hudson, N.A. (1984). Novel dimeric chalcone-based pigments from Brakenridgea zangueharica. Phytochemistry 22, 105-108. Drewes, S.E. and Liebenberg. R.W. (1982). Novel pcntenyne derivative as potential anticancer agent. British Potent No 8211294 (19 April 982). Drewes, S.E. and Taylor, C.W. (1994). Methylated A-lype proanthocyanidins from Cassipourea gerrardii. Phytochemistry 37, 5 5 1 -555. Drewes, S.E., Hall, A.J., Learmonth, R.A., and Upfold, U.J. (1984). Isolation of hypoxoside from Hypoxis rooperi and synthesis of its aglycone. Phytochemistry 23, 1313-1316. Drewes, S.E., Hudson, N.A., Bates, R.B.. and Lin/, G.S. (1987). Medicinal plants of Southern Africa. Journal of the Chemical Society, Perkin Transactions /, 2809-2813. Drewes, S.E., Taylor, C.W., Cunningham. A.B.. Ferreira D., Sleenkamp. J.A., and Mouton, C.H.L. (1992). Epiafzelechin from Cassipourea gerrardii. Phytochemistry 31. 2491-2494. Constituents of muthi plants of Southern Africa: magical and molluscicidal properties 265

Drcwes, S.E., Sehlapelo, B.M., Horn, M.M., Scotl-Shaw, R., and Sandor, P. (1995). 5,6-Dihydro- rx-pyrones from Cryptocarya latifolia. Phytochemistry 38, 1427-1430. Marini-Bettolo, G.B., Patamia, M., Nicolctli, M, Galeffi, C., and Messana, I. (1982). Hypoxoside, a new glycoside from Hypoxis obtusa. Tetrahedron 38, 1683-1687. Sehlapelo, B.M., Drewes, S.E., and Sandor, P. (1993). Ocobullenone from Ocotea bullata, Phytochemistry 32 1352-1353. This work is licensed under a Creative Commons Attribution - Noncommercial - NoDerivs 3.0 License.

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