The African Potato
Hypoxis Hemerocallidea [hypoxidaceae]

Myth or miracle muthi

Siegfried Drewes & Marion Horn
Dept of Chemistry & Chemical Technology
University of Natal, Pbag X01, Scottsville3209 Pietermaritzburg

 

 


A great deal has been written particularly in the popular press on South Africa’s "miracle muthi". this muthi originates from the plant Hypoxis hemerocallidea [formerly H. rooperi]. Zulu name "inkomfe". Since its "popularisation" the plant is frequently referred to as the African Potato. We as well as most botanists, agree with Esa Pooley[1993] that this is a most inappropriate name , since the below the ground portion of the plant does not resemble a potato [which is a swollen stem tuber], either in looks or texture, and is indeed a corm [a swollen stem of several internodes and nodes which develops at or below ground level in a vertical position.]

Since we are closely associated with the original isolation of the phenolic chemical constituents of the plant [Drewes 1984], it seemed appropriate to place on record certain information. At the same time this provides an opportunity to clear up certain misconceptions regarding the chemical composition of the plant.

In a recent article [Drum1997] the writer records several claims which are made for "the remedy" emanating from the Hypoxis plant .These include, among others, its efficacy as stimulant of the immune system [and thus indirectly an aid to aids sufferers]. As an agent for slowing down the growth of certain types of cancer, as having a positive effect in combating "yuppie flu", and as being highly effective in the alleviating arthritis. Professor Piet van Jaarsveld, from the Pharmacy Department at Stellenbosch University is quoted as saying [Drum 1997] that in future "people will drink it [the remedy] to prevent colds and infections, the way they now take vitamins."

Most books on muthi plants, such as the one by Anne Hutchings [1996] state that the Zulu medical usage of Hypoxis extracts is in the realm of emetics, and for the treatment of dizziness and mental disorders. Watt & Breyer - Brandwijk [1962] quote a variety of uses including the healing of septic sores, alleviation of headaches, as a purgative and as an ascarifuge. Ben-Erik van Wyk and his co-authors [1997] writing on the medicinal plants of South Africa, quote earlier sources relating to the use of Hypoxis extracts for healing testicular tumours, prostrate hypertrophy and urinary infections.

The sudden awareness of the man [or woman] in the street of the Hypoxis plant has no doubt been fired by the press statements [ Pienaar 1997], Younghusband 1997] an TV programmes, but there have also been other developments. These include the appearance on the shop floor of a patented preparation ‘"Moducaretm" [Phytolabs [Pty] Ltd Midrand 1685], coupled with initiatives by private entrepreneurs. This usually takes the form of a dark brown brew, in a 750ml bottle, being offered for sale at public places, and in the advertisement pages of KZN newspapers, and labeled "African Potato Extract". The price is generally round R10 per bottle and the instruction is to keep it in the fridge and to take a " brandy tot portion 3 times per day".

The question is. What do these two preparations contain? The Moducaretm product specifies that each capsule holds 20mg plant sterols and 0.2mg plant sterolins, and that this mixture is "an essential dietary supplement to cope with a strenuous life style".

Professor Karl Pegel [1997], in his authoritative treatise on the importance of sitosterol and sitosterolins in human and animal nutrition, and drawing, no doubt on his experience of isolating these substances from the Hypoxis plant in the early 1970"s points out that these substances have a proven beneficial effect on the human immune system. he also draws attention to the fact that as early as 1974, a preparation going under the name of Harzol4 , and containing sitosterols and its glucoside [sitosterolins], was sold in Germany for the treatment of benign prostrate hypertrophy. This product was originally prepared in South Africa from Hypoxis plants, but later on was manufactured synthetically.

Our examination of the Moducaretm preparation by the simple technique of thin layer chromatography [TLC] showed that, apart from the ever-present extender used in all capsuls, the only other constituents are b-sitosterol and sterols of closely related structure. These components migrate up the TLC plate as a single spot and can be visualised as dark blue spots on a white background by spraying with a suitable reagent [fig 1, spot number 4].

 

This Thin Layer Chromatography plate showing compositioia of various hypoxisand sitosterol preparations. Solvent system 2# butanol-Toluene-water-Methanol [4:3:2:1]
  1. Aqueous extract purchased commercially

  2. Pure hypoxoside from hypoxis hemerocallidea

  3. Same as 1 low concentrations

  4. Sitosterols from ModucareTM

Figure 1

 

Next we turned our attention to the aqueous Hypoxis brew which we had purchased from a local producer. This was not an unfamiliar mixture since one of us [Drewes 1981], has an association with the plant dating back to 1979. At this time Mr R.W. Liebenberg a prominent businessman from Midrand requested that we should endeavour to isolate and identify the anti-cancer component in H rooperi [as it then was] as opposed to the known sitosterol components. Within six months we had identified a new phenolic compound then not known to science. The next hurdle was to establish that this compound had anti-cancer properties. With the aid of co-workers in the medical field it was established that the compound, then called P2A, had definite anti-cancer properties. By late 1981 we were ready to publish our findings but were persuaded by our sponsors [ Mr Liebenberg’ s Company ] that it was advisable to first finalise certain provisional patents. To our dismay, Professor Marini Bettolo [1982] published the full story on " our" compound in 1982. The good Professor, on a visit to Mozambique from Rome, had come across a street vendor at Maputo Airport, who was selling Hypoxis corms. The rest is history, except that Professor Marini Bettolo was unaware of the fact that the new compound had anti-tumour properties. We finally published our paper [Drewes1984] in 1984. Not only did we report its isolation that the compound named hypoxoside by Professor Marini Bettolo, was inactive in the form in which its was present in the plant but became highly active after hydrolysis with the enzyme b-glucosidase. To the active anti-cancer compound we gave the name rooperol and its structure is shown in figure 2.

Figure 2. Structure of Hypoxoside and Rooperol

The next stage of the work on Hypoxis [1986-1997] was carried out at Tygerberg Hospital and the Department of Pharmacology at Stellenbosch University under the direction of Dr. Carl Albrecht. The findings of these researches have been published in recent issues of the S.African Medical Journal [Albrecht 1995] and they concluded that "rooperi has promising properties as an oral prodrug for cancer therapy in humans given its first-pass metabolism into non-toxic conjugates which may be activated in tumours with high deconjugase activity". Subsequent to this research Professor Patric Bouic . [DRUM 1997], from the Medical School at Stellenbosch University has investigated further the immunity boosting properties of the Hypoxis extracts.

Can one now answer the critical question which obviously bothering many people. "Can I take Moducaretm for my arthritis [ or other ailments], or should I rather take the much cheaper aqueous brew? The answer with regards to the Moducare is implicit in what has already has been written here phytosterols has a recorded history of boosting the immune system of the human body and Moducare provides these in a concentrated form whether a healthy diet of fresh fruit and vegetables [also loaded with phytosterols] will provide the same effect is open to debate.

How does the raw Hypoxis extract compare, particularly as it contains an anti-cancer compound in addition to the phytosterols? The following should be considered in trying to formulate an answer.

  1. The raw aqueous extract contains far less phytosterols than a dose of moducare.
  2. The TLC examination [fig 1] shows very clearly that apart from the main components [spot 2] with the proven anti-cancer properties there are at least three other compounds present in high concentrations [see spot 1] in the extract. Also, despite storing the extract in the fridge a considerable degree of degradation has taken place as is evidenced by the dark stain [spot 1] on the starting line.

Our advice: With the present fragmentary knowledge regarding the effects on the human body of the complex mixture of compounds present in the whole extract of the Hypoxis plant, we would advise caution in hurriedly "taking to the bottle". With the new initiatives currently being explored by the pharmaceutical industry in regard to "botanicals", i.e. a new class of medicines consisting of a mixture of known natural components but in which the chemical composition is not fully specified we predict it is only a matter of time before a suitable botanical incorporating a combination of the best from Hypoxis [i.e. a mixture which links anti-tumour properties with immune-system-boosting properties], appears on the market. Then go for it!

This paper is dedicated to my [SED] earliest co-workers on the Hypoxis project. Alida Hall [now in Canada], Ursula Scogings[ n`ee Upfold, now in New Zealand] and Robert Learmonth [now at the CSIR].


Acknowledgements

Dr. Tanza Crouch kindly provided the illustration of the Hypoxis Hemerocallidea

The University of Natal Research Fund is thanked for financial assistance.

References

ALBRECHT C.P. THERON E.J. & KRUGER P.B. 1995 morphalogical characteristion of the cell-growth inhibitory activity of rooperol. S.A. Medical Journal1985. 853-860

DREWES. S.E., HALL. A.J., LEARMONTH, R.A. & UPFOLD, U.J. 1984. Isolation of hypoxoside from Hypoxis rooperi and synthesis of [E]-1,5 Bis[3’,4’-dimethoxypheny1] pent-1-en-1-ync. Phytochemistry 23. 1313-1316.

DRUM MAGAZINE 1997. S.A’s miracle muti. July 8 to and 24

HUTCHINGS, A., SCOTT, A.H., LEWIS, G. & CUNNINGHAM, A.B., 1996. Zulu medicinal plants. Natal University Press, Pierermaritzberg

Marini Bettolo,O.B., Patamia, M., NICOLETTI, M., GALEFFI, C. & MESSANA, I.1982 Hypoxoside, a new glycoside of uncommon structure from Hypoxis obtusa bosch . Teroliedron 38. 1683-3687.

PEGEL, K.N. 1997. The importance of sitosterol and sitosterolins in human and animal nutrition. S.A. J. Science 93. 263-268

PIENAAR, J. 1997. Oerkuie van SA plant kan help. Die Burger 22nd Feb.

POOLEY, E. 1993. The complete guide to trees of Natal, Zululand and Transkei. Natal Flora Trust Publications. Natal Herbarium, Durban.

VAN WYK, B-E., VAN OUDTSHOORN, R.& GERICKE, N. 1997. Medicinal plants of S.A... Brisa Publications, Pretoria.

WATT, J, M. & Breyer-BRANDWIJK, M.G. 1962. Medical and poisonous plants of Southern and East Africa.E and S Livingstone, Edinburgh.

YOUNGHUSBAND, T. 1997 Centuries old muti plant shakes medical world. Sunday Tribune 2nd March.


Siegfred Drewes is Emeritus Professor and honorary research associate in the chemistry department at the University of Pietermaritzburg. He has published widely on natural products chemistry, and in particular "Muthi chemistry ". He coined the name "Rooperol" for the major component of the Hypoxis Hemerocallidea.

Marion Horn works with Prof. Drewes, has a BSc Engineering degree from the Technicon in Haifa, Israel and was recently awarded an MSc at Natal for her work on Burchillia bubalina