Plasmodial Resistance and the potential of herbal extracts in the treatment of malaria

Those that live in Africa or other areas where malaria disease is endemic are quite aware of the menace it poses to the lives and health of the human populace in these regions. If the reports of the World Health Organization in 2015 is anything to go by (of course, it is!), it simply means that about 3.4 billion people distributed in 91 countries all over the world are at risk of being infected with the notorious disease. Two hundred and eleven million cases were reported in 2015 alone while the incidence of infection went up a notch in 2016 with an estimated two hundred and sixteen million being infected.

^{By Gething P, Patil A, Smith D, Guerra C, Elyazar I, Johnston G, Tatem A, Hay S - Image file from Gething P, Patil A, Smith D, Guerra C, Elyazar I, Johnston G, Tatem A, Hay S (2011). "A new world malaria map: Plasmodium falciparum endemicity in 2010". Malaria Journal. DOI:10.1186/1475-2875-10-378. PMID 22185615. PMC: 3274487., CC BY 2.0, Link}

The disease, which is usually caused by protozoas in the genus Plasmodium and transmitted by mosquitoes has claimed lives in the past before breakthroughs were made in the area of treatment. However, the scourge of death from the disease though abated with drug discoveries has not really been eliminated. In 2015 alone, about 446,000 lives were reported to have been lost to malaria while an estimated figure of 445,000 lives was lost in 2016.

Interestingly, susceptibility to malarial attacks has been linked to several genetic indices including the shape and general structure of the human haemoglobins. One of the evidences supporting this hypothesis is a research investigation carried out by Opara and his team in 2003 to determine if infants and young children with some peculiar genetic traits would show a similar reaction to malarial parasite infestation. One of their findings showed that children with blood genotype AA were more susceptible to malarial infection as compared to AS and SS. They discovered a significant correlation between haemoglobin genotype and malarial infection.

There is no gainsaying in the fact that malaria disease has been and continues to be a pain in the asses of those of us with blood genotype AA living in the zones of malarial endemicity. In the last few years, malarial infection has punctuated my good health at a relatively constant frequency of once in three months. I am sure some folks have it worse.

Drugs for treating malaria has evolved from the first event of isolation of artemisinin from the Qinghao plant in the 4th century, quinine from the Chinchona tree in the 17th century to the present combination therapy that is generally recommended for effective treatment of the disease. Treatment drugs keep evolving either as a result of the development of resistance to the drug by Plasmodium or problems associated with taking of the drug (terrible side effects).

Artemisinin-based Combination Therapy (ACT) drugs have been widely used and are still the in-vogue drugs for the treatment of malaria. However, little by little, the story is changing and there might be an urgent need to review the effectiveness of the ACT drugs. The parasite has been hypothesized to be developing resistance to the drugs as a result of modifications in the kelch13 propeller region located on chromosome 13 of its genome and functions as kelch protein encoder. This is known as the kelch propeller hypothesis.

The resistance of malarial parasite to artemisinin-based combination therapy was first observed in South-East Asia but over the years, the phenomenon has been observed in other countries with the incidence of malaria diseases. Nothing less than twelve African countries have been reported to have recorded incidence of resistance of malarial parasites to ACT drugs, Nigeria inclusive. According to a particular report, 80 to 90% of patients with malaria in Nigeria have at least one mutated malarial parasite in their blood sample.

Malaria could be deadly if not treated on time and the development of resistance to available drugs is posing a major concern to scientists that are working day and night to eliminate the disease.

I recently came down with malaria (the more reason I have not blogged for a while) and as usual, consulted a doctor who confirmed the diagnosis and prescribed an ACT drug for its treatment. The drugs were taken as prescribed but to my chagrin, the symptoms refused to abate. I was at a crossroad, whether to get another dose of the drug as adviced by the doctor or just wait and watch if the symptoms would go away after some time. I suspected that the malarial parasites in my system have developed resistance to the ACT drugs I normally take and opted against taking another dose of the same drug.

After what seemed like an eternity suffering under the symptoms, I yielded to the persuasion of my family to try out a hot water infusion of a leaf that has been locally reported to have antiparasitic properties against malarial parasites. Even though the hot water infusion is largely unrefined and has no distinct way of dosage measurement, it was quite effective in dispersing malarial symptoms within a few days. Few ml of the liquid taken for three days was quite far effective in the treatment of malaria where ACT drugs failed. Could herbal extracts be the future of malarial treatment?

^{Aqeuous extract of Thaumatococcus daniellii used in the treatment of malaria. Image taken using Samsung A10 (2016)}

Several aqueous or ethanolic plant extracts have been reported both locally and in literature to have antiparasitic properties against Plasmodium species. According to The Research Initiative on Traditional Antimalarial Methods, there are over 1200 plant species from 160 different plant families which have been tested and found to be effective in the treatment of malaria. Out of these number, few have been reported to have mild side effects. In a particular town in Nigeria, about fifty plant species found within the locality were reported to be involved in the treatment of the disease. While some of them are used singly, a large portion of the plants is used in different combination ratios.

^{Thaumatococcus daniellii By Ji-Elle - CC BY-SA 4.0, Link}

However, as effective as these plants may have been in the treatment of malaria, care should be taken in the consumption of their crude extracts because of potential cytotoxicity. Although no significant cytotoxicity have been reported on any of the plants so far, it is still an active area of research. On a brighter side, the reported plants serve as a major outlet in the research for new antimalaria drugs in the wake of resistance of Plasmodium to the existing ones.

Thank you all for reading.