Why African star apple, lime can suppress malaria

EXTREME care should be taken in mixing plant-based remedies and conventional drugs as well as in the choice of plants to be combined in herbal formulations or decoctions as some may affect the remedy’s efficacy to counter the effects of a malaria-causing parasite, become toxic or encourage the development of parasite resistance to these orthodox drugs.

One of the many groups of herbal remedies used in Nigeria is that which contains leaves and bark of Chrysophyllum albidum, what is commonly known as the African star apple and leaf and fruits of a lime tree.

In a study, experts found that combining herbal remedies made with leaves and fruits of lime like fruits of the African star apple with Pyrimethamine, a standard malaria drug, can serve as a good preventive treatment for malaria.

Also, there is no justification for the co-administration of any of these four plants with pyrimethamine in the prophylaxis of malaria. However, such a remedy that contains the stem of an African star apple counters its efficacy in the prevention of malaria.

The 2020 study in the Annals of Complementary and Alternative Medicine involved Samuel Akintunde Odediran at the Obafemi Awolowo University, Ile- Ife, Osun State in collaboration with other researchers, including Kayode Ebenezer Awosode  and Taiwo Adebomi Adegoke.

It was to establish antimalarial activities for these plant parts, determine the plant and part with the best prophylactic, chemo suppressive and curative activities, effects of these extracts on orthodox drugs, and any beneficial antimalarial effects of these plant combinations.

Also, it was to evaluate the common African practice of co-administration of herbal drugs with orthodox antimalarial drugs, especially with regards to the effectiveness, safety or toxicity of such practice, and determining if truly plant combinations, as practised in African ethnomedicinal, have any beneficial effect in malarial therapy.

In this study, four extracts from lime leaf and stem bark and African star apple leaf and fruit were tested individually, in combinations with standard drugs of Chloroquine and Pyrimethamine, and with each other, in a group of five Swiss albino mice.

These remedies when combined with chloroquine significantly lowered the suppressive and curative effects of chloroquine on the malaria-causing parasite. Only decoctions made from leaves of African star apple and lime fruits as well as fruits and leaves of lime gave comparable and significantly higher curative activity than chloroquine.

African star apple, a fruit cherished for its sweet taste by many people has various ethnomedical uses, including traditional rituals and medico-magical.  Different parts of the plant are used to treat varied ailments, including malaria and yellow fever. Its bark and leaves are used in treating malaria, skin eruption occasioned by infections and inflammatory reactions.

Lime is used in traditional medicine as an antiseptic, antiviral, antifungal, anthelmintic, and mosquito repellent, and also for a plethora of diseases, including arthritis, colds, coughs, etc. Lime and lemon juice are also widely used for douches among women at high risk of HIV transmission in Central Nigeria and as a barrier contraceptive due to their anti-fertility potential.

It is common knowledge that some home patients or those admitted to Nigerian hospitals, especially those with resistant malarial or other parasitic infections or suffering from chronic diseases, such as hypertension, cancer and diabetes, concomitantly use orthodox drugs and herbal preparations.

According to the researchers, “However, it was worrisome that the equally prophylactic and curative active C. albidum stem bark gave the significantly lowest survival times in the mice. This may be an indication of the toxicity of CAB and calls for caution in its use and demands a full investigation of its toxicity profile.

“Also, the poor prophylactic activity and low survival times given by C. aurantifolia leaf and fruits may suggest that they should not be used in prophylaxis of malaria. These parts may be more beneficial in their traditional use of repelling/killing mosquitoes among others.

“Furthermore, the doubling of survival time of the mice given by C. aurantifolia fruit agreed with the fact that it gave the highest (93%) suppression of malaria parasite, thereby confirming it as a good malarial suppressive plant drug.

“The C. albidum leaf and stem bark gave 76% and 94% reductions in malaria parasite load. Therefore, for foreign visitors to the malarial endemic tropical African or Asian countries, C. albidum leaf should offer the needed protection throughout their stay, similar to other orthodox medications, such as atovaquone/proguanil, doxycycline, mefloquine and primaquine.

“Also, the chemo-suppressive C. aurantifolia fruit would only be appropriate for citizens residing in malaria-endemic countries, as they are always exposed to these mosquitoes and parasites. Hence, similar to microbial infections, where antibiotics significantly reduce the microbial load to the level that the human immune system could effectively get rid of them, antiplasmodial suppressive plants would only sufficiently keep down the malarial parasites’ load, thereby preventing sickness or manifestation of malaria symptoms.”