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Pharmacy & Pharmacology International Journal

Opinion Volume 6 Issue 4

New approaches in malaria prophylaxis: endophytic fungi, asparaginase, potassium and papaya

Pierre Lutgen

IFBV-BELHERB, Luxembourg

Correspondence: Pierre Lutgen, IFBV-BELHERB, BP 98 L-6905, Niederanven, Luxembourg

Received: June 06, 2018 | Published: July 6, 2018

Citation: Lutgen P. New approaches in malaria prophylaxis: endophytic fungi, asparaginase, potassium and papaya. Pharm Pharmacol Int J. 2018;6(4):275-277. DOI: 10.15406/ppij.2018.06.00186

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Malaria infection is initiated when a mosquito injects Plasmodium sporozoites into a mammalian host. Sporozoites exhibit gliding motility both in vitro and in vivo. This motility is associated with the secretion of at least two proteins, circumsporozoite protein (CSP) and thrombospondin-related anonymous protein (TRAP). Several molecules, as for example albumin promote this motility by mechanisms which are not well understood. The use of skin care products containing albumin is thus questionable. Most of these ingredients are derived from soybean.1,2 But there are other molecules which inhibit the motility of sporozoites.

The role of endophytic fungi and asparaginase

Endophytic fungi or endophytes exist widely inside the healthy tissues of living plants, and are important components of plant micro-ecosystems. Over the long period of evolution, some co-existing endophytes and their host plants have established a special relationship with one and another, which can significantly influence the formation of metabolic products in plants, then affect quality and quantity of crude drugs derived from medicinal plants.3 Liver-stage Plasmodium parasites exhibit one of the fastest nuclear replication rates known among eukaryotic organisms leading to the formation of several thousand progeny. This extensive and rapid growth necessitates the acquisition of many nutrients.4 The proteins of Plasmodium, the malaria parasite, are strikingly rich in asparagine. Plasmodium depends primarily on host haemoglobin degradation for amino acids and has a rudimentary pathway for amino acid biosynthesis, but retains a gene encoding asparagine synthetase. The deletion of asparagines in Plasmodium berghei delays the liver-stage development and leads to a substantial reduction in the formation of ookinetes, oocysts and sporozoites in mosquitoes. Conversion of asparagine into aspartic acid and depletion of blood asparagine levels infected mice with the enzyme asparaginase completely prevents the development of liver stages, ex-flagellation of male gametocytes and the subsequent formation of sexual stages. In vivo supplementation of asparagine in mice restores the ex-flagellation. Thus, the parasite life cycle has an absolute requirement for asparagine, which could be targeted to prevent malaria transmission and liver infections.5,6 Asparagine is an amino acid present in vegetables like asparagus, peas or beans. It is absent in Artemisia annua.7 It is also found in many honeys.8

Asparaginase is an enzyme that is used in medicine and in food manufacturing. As a medication it is used to treat acute lymphoblastic leukemia, acute myeloid leukemia, and non-Hodgkin's lymphoma. The cancer cells thrive on large quantities of asparagine. Asparaginase, however, catalyzes the conversion of L-asparagine to aspartic acid and ammonia. This deprives the leukemic cell of circulating asparagine, which leads to cell death. It will also deprive Plasmodium of the asparagine it badly needs. Additionally, the production of ammonia may present a huge toxicity challenge to a parasite that lack ammonia-detoxifying machinery.9 E. coli strains are the main source of medical asparaginase. It is generally carried out by submerged fermentation, and this may explain why it is present in wines and beers. It is produced at industrial scale by the use of agro-wastes, like peels of onions, of oranges, of garlic. But it is also present in several medicinal plants, Ocimum tenuiflorum, Carica papaya, Azadirachta indica.10,11 Asparaginase was approved for medical use in the United States in 1978. It is an authorized food additive.12 Asparaginase was first detected in the developing seeds of Lupinus albus.13,14

Studies from Thailand and India show that many medicinal plants are rich in asparaginase, and that it is even the predominant enzyme compared to others present like amylase, cellulose, pectinase.15‒18 Artemisia plants are rich in fungal endophytes with a great variety in species.19‒22 Different fungal communities colonize stems and leaves. This may explain why it is claimed that it is important to keep twigs and stems in dried Artemisia annua for tea infusions. Artemisia plants are more than other plants very rich in potassium and don’t contain any sodium (EA Brisibe, op.cit.). There may exist a synergetic effect between potassium and asparaginase in Artemisia plants. A more complete study in Pakistan, comparing 10 medicinal plants finds that potassium content in Artemisia annua is the highest.23‒25 This synergy between potassium and asparaginase was confirmed by a seminal work in Brazil. The enzyme is dependent upon the presence of K⁺ for activity. Maximum activity was obtained at K⁺ concentrations above 20millimolars. Potassium also exerts an import role in the stabilization of asparaginase at elevated temperatures. This stabilizing effect is separate from its activating effect. Under conditions where the enzyme shows a reasonable degree of stability in the absence of K⁺, i.e., at 20°C the enzyme is still inactive unless potassium is present (see Figure 1).26,27

Figure 1 Effect of increasing concentration of KCI on asparaginase activity isolated from test and cotyledon of immature P. sativum seeds.

Papaya has a solid reputation as antimalarial plant not only in South America but also in Africa. As stated in Wikipedia:” In some parts of the world, papaya leaves are made into tea as a treatment for malaria, but the mechanism is not understood”. Most studies deal with leave extracts, but seed extracts have also been demonstrated to be very active in vivo with efficacies similar to that of chloroquine.28‒31 Papaya leaves are a rich source of L-asparaginase when compared to other plants. This may be one of the reasons of its prophylactic and antimalarial properties.32 In Papaya carica like in Artemisia annua, potassium is the mineral present at the highest concentration.33 Cocoa (Theobroma cacao) also contains asparaginase. It was known by the Maya as diet-mediated antimalarial prophylaxis. Based on this anecdotal information prophylactic trials have been started in Ghana by the Ghana Cocoa Board. People are encouraged to daily drink a beverage made by mixing boiling hot water and natural cocoa powder.34,35 This has been confirmed by in vivo trials in mice. Cocoa powder was equivalent to chloroquine and has also prophylactic properties.36 Possible effects of asparaginase on gametocyte motility.

Transmission of Plasmodium parasites to the mosquito requires the formation and development of gametocytes. Studies in infected humans have shown that only the most mature forms of Plasmodium falciparum gametocytes are present in circulation, whereas immature forms accumulate in the hematopoietic environment of the bone marrow. Only mature gametocytes reappear in the peripheral circulation. A recent paper shows that these mature gametocytes show high deformability and the authors suggest that gametocyte mobility is essential for transmission of Plasmodium to the mosquito. Speeds of 5 to 10μm/s were observed. It is comparable with motile “zoite” forms of the parasite such as sporozoites. The deformability and motility of mature gametocytes was blocked by sildenafil citrate.37 Regulated K⁺ transport is of vital importance for the survival of most cells. Two K⁺ channel-encoding genes have been found in Plasmodium falciparum genome.38 Sulfadoxine-pyrimethamine impairs Plasmodium falciparum gametocyte infectivity. It is possible that Artemisia plants also contain molecules which block the mature gametocytes. A study from South Africa shows that compared with eight other medicinal plants Artemisia afra ranks at the top for the inhibition of gametocyte viability.39,40



Conflict of interest

The author declares that there is no Conflict of interest.


  1. Stewart MJ, Vanderberg JP. Malaria sporozoites release circumsporozoite protein from their apical end and translocate it along their surface. J Protozool. 199;38(4):411‒421.
  2. Kebaier C, Vanderberg JP. Initiation of Plasmodium sporozoite motility by albumin is associated with induction of intracellular signaling. Int J Parasitol. 2010;40(1):25‒33.
  3. Jia M, Chen L, Xin HL, et al. A Friendly Relationship between Endophytic Fungi and Medicinal Plants: A Systematic Review. Front Microbiol. 2016;7:906.
  4. Nyboer B, Heiss K, Ingmundson A, et al. The Plasmodium liver-stage parasitophorous vacuole: a front-line of communication between parasite and host. Int J Med Microbiol. 2017;S1438-4221(17):30292‒30298.
  5. Nagaraj VA, Mukhi D, Sathishkumar V, et al. Asparagine requirement in Plasmodium berghei as a target to prevent malaria transmission and liver infections. Nat Commun. 2015;6:8775.
  6. Silvie O, Goetz K, Matuschewski K. A Sporozoite Asparagine-Rich Protein Controls Initiation of Plasmodium Liver Stage Development. PLoS Pathog. 2008;4(6):e1000086.
  7. Brisibe EA, Ferreira JF, Xianli Wu, et al. Nutritional characterization and antioxidant capacity of different tissues of Artemisia annua L. Food Chemistry. 2009;115(4):1240‒1246.
  8. Kowalski S, Kopuncová M, Ciesarová Z, et al. Free amino acids profile of Polish and Slovak honeys based on LC-MS/MS method without the prior derivatisation. J Food Sci Technol. 2017;54(11):3716‒3723.
  9. Kimoloi S, Rashid K. Potential role of Plasmodium falciparum-derived ammonia in the pathogenesis of cerebral malaria. Front Neurosci. 2015;9:234.
  10. Kumar R, Sedolkar V, Gaddad S. Isolation, Screening and Characterization of L-asparginase producing fungi from medicinal plants. Int J Pharm Sci. 2015;8:281‒283.
  11. Shakamari G, Kumar R, Varalakshmi P. Agro-Waste utilization for cost-effective production of L-Asparaginase by Pseudomonas plecoglossicida RS1 with anticancer potential. ACS Omega. 2017;2:8108‒8117.
  13. Atkins CA, Pate JS, Sharkey PJ. Asparagine metabolism- key to the nitrogen nutrition of developing legume seeds. Plant Physiol. 1975;56(6):807‒812.
  14. Sodek L, Lea PJ. Asparaginase from the testa of developing lupin and pea seeds. Phytochemistry. 1993;34(1):51‒56.
  15. Theantana T, Hyde KD, Lumyong S. Asparaginase production by endophytic fungi from Thai medicinal plants. KMITL Sci. Tech. J. 2009;7(1):13‒18.
  16. Uzma F, Konappa NM, Chowdappa S. Diversity and extracellular enzyme activities of fungal endophytes isolated from medicinal plants of Western Ghats. Egyptian Journal of Basic and Applied Sciences. 2016;3(4):335‒342.
  17. Abhini KN, Fathimathu Zuhara K. Isolation Screening and Identification of Bacterial Endophytes from Medicinal Plants as a potential source of L-Asparaginase Enzyme. Journal of Chemical and Pharmaceutical Sciences. 2018;11(1):73‒76.
  18. Nongkhlaw FMW, Joshi SR. L-Asparaginase and antioxidant activity in endophytic bacteria associated with ethnomedicinal plants. Indian Journal of Biotechnology. 2015;14(1):59‒64.
  19. Cosoveanu A, Cabrera R. Endophytic Fungi in Species of Artemisia. J Fungi. 2018;4(2):53.
  20. Astuti P, Wahyona W, Titik N, et al. Antimicrobial and cytotoxic activities of Endophytic Fungi from Artemisia annua. J App Pharm Sci. 2014;4(10):47‒50.
  21. Purwantini I, Asmah R. Isolation of Endophytic Fungi from Artemisia annua and identification of their antimicrobial compound. Int J Phar Pharm Sci. 2015;7(12):95‒99.
  22. Baquet A, Lavoinne A, Hue L. Comparison of the effects of various amino acids on glycogen synthesis, lipogenesis and ketogenesis in isolated rat hepatocytes. Biochem J. 1991;273(Pt 1):57‒62.
  23. Iqbal Hussain. Evaluation of Inorganic Profile of Selected Medicinal Plants of Khyber Pakhtunkhwa Pakistan. World Appl Sci J. 2011;12(9):1464‒1468.
  24. Bejger M, Imiolczyk B, Clavel D, et al. Na/K exchange switches the catalytic apparatus of potassium dependent plant L-asparginase. Acta Crystallogr D Biol Crystallogr. 2014;70(Pt 7):1854‒1872.
  25. Lutgen P, Tchandema C. Potassium in Artemisia plants, a key factor in malaria control. Malaria world;2014.
  26. Sodek L. Distribution and Properties of a Potassium-dependent Asparaginase Isolated from Developing Seeds of Pisum sativum and Other Plants. Plant Physiol. 1980.65(1):22‒26.
  27. Hughes FM, Cidlowski JA. Potassium is a critical regulator of apoptotic enzymes in vitro and in vivo. Adv Enzyme Regul. 1999;39:157‒171.
  28. Amazu LU, Ebong OO. Effects of the methanolic seeds extract of Carica papaya on Plasmodium berghei infected mice. Asian Pacific J Trop Med. 2009;2(3):1‒6.
  29. Uhegbu FO, Elekwa I, Ukoha C. Comparative efficacy of crude aqueous extract of Mangiferea indica, Carica papaya and sulphadoxine pyrimethamine on mice infested with malaria parasite in vivo. Global Journal of Pure and Applied Sciences. 2005;11(3):399‒401.
  30. Longdet IY, Adoga EA. Effect of Methanolic Leaf Extract of Carica papaya on Plasmodium berghei Infection in Albino Mice. European Journal of Medicinal Plants. 2017;20(1):1‒7.
  31. Bhat GP, Surolia N. In vitro antimalarial activity of extracts of three plants used in the traditional medicine of India. Am J Trop Med Hyg. 2001;65(4):304‒308.
  32. R Kumar, V Sedolkar, A Triveni. Isolation, Screening and Characterization of L-Asparaginase from Medicinal plants. Int J Pharm Pharm Sci. 2015;8(1):281‒283.
  33. Sharma DK, Tiwari B, Sandeep S, et al. Estimation of Minerals in Carica papaya L. Leaf found in Northern India by using ICP-OES Technique. International Journal of Scientific & Engineering Research. 2013;4(6):1012‒1019.
  34. Addai FK. Natural cocoa as diet-mediated antimalarial prophylaxis. Med Hypotheses. 2010;74(5):825‒830.
  35. Amponsah SK, Bugyei KA, Osei-Safo D, et al. In vitro activity of extract and fractions of natural cocoa powder on Plasmodium falciparum. J Med Food. 2012;15(5):476‒482.
  36. Jayeola CO, Kale OE. Anti-malarial activity of cocoa powder in mice. Afr J Biochem Res. 2011;5(11):328‒332.
  37. De Niz M, Meibalan E, Marti M, et al. Plasmodium gametocytes display homing and vascular transmigration in the host bone marrow. Sci Adv. 2018;4(5):eaaat3775.
  38. Ellekvist P, Maciel J, Kumar N, et al. Critical role of K⁺ channel in Plasmodium berghei transmission revealed by targeted gene disruption. PNAS. 2008;105(17):6398‒6402.
  39. Moyo P, Botha ME, Nondaba S, et al. In vitro inhibition of Plasmodium falciparum early and late stage gametocyte viability in exctracts from eight traditionally used South African plant species. J Ethnopharmacol. 2016;185:235‒242.
  40. Pierre Lutgen. Tannins in Artemisia: the hidden treasure of prophylaxis. Pharm Pharmacol Int J. 2018;6(3):176‒181.
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