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INNOSC Theranostics and
Pharmacological Sciences Residual versus curative antimalarial tests

use. Furthermore, other studies [31,35] have demonstrated and L. inermis have both curative and repository effects in
good in vivo antiplasmodial activity of N. latifolia, with the the mice infected with P. berghei. However, the antimalarial
highest activity observed in the prophylactic test. effect of the extracts was found to be higher when
Repository experiments revealed that chloroquine is a administered before infection rather than after infection.
very weak prophylactic agent, which can be attributed to These results agree with the traditional use of these plants
its mechanism of action as a blood schizontocidal agent. and provide a scientific basis for their continuous use. The
Chloroquine, like other quinine derivatives, requires the findings in the present study encourage further research
presence of free heme to act. The free heme produced on these plants, which have demonstrated antiplasmodial
during the hydrolysis of hemoglobin is toxic to the parasite activity, with the view to developing new antiplasmodial
and, therefore, must be removed or detoxified. However, drugs.
the malaria parasite lacks enzymes for detoxification, Acknowledgments
and therefore, heme is detoxified by converting it into a
nontoxic malaria pigment called hemozoin. Chloroquine The authors would like to thank the respondents to the
inhibits the detoxification reaction by binding to heme, questionnaires in Omu-Aran, Kwara State, Nigeria, and
hence preventing the destruction of parasites in liver equally appreciate the director of the Centre for Traditional
cells where no hemoglobin digestion takes place . Medicine and Drug Research (CTMDR). The technical
[44]
Consequently, the singular use of chloroquine in the assistance of Mr. Enoch Moindi and Mr. Ogutu of KEMRI
prevention and treatment of malaria has led to the animal house during the in vivo antiplasmodial experiment
widespread distribution of chloroquine-resistant strains. is well appreciated.
The discontinuation of chloroquine usage has reduced
the drug pressure, resulting in a decrease in chloroquine- Funding
resistant Plasmodium parasites . It was observed that This research did not receive any specific grant from
[45]
after 12 years of chloroquine withdrawal from use in funding agencies in the public, commercial, or not-for-
Malawi, its efficacy in the treatment of malaria has shown profit sectors.
signs of returning . Similar observations of chloroquine
[46]
efficacy returning against Plasmodium vivax malaria Conflict of interest
in Ethiopia and the Saharan Zone in Mauritania after
the use of artemisinin-based combination therapy have The authors declare no conflict of interest.
been reported [47,48] . Moreover, chloroquine has shown a Author contributions
greater chemo suppressive activity than the extracts and
fractions of the plants used in this study in the curative Conceptualization: Funmilayo I. D. Afolayan
test. However, due to resistance, chloroquine is no longer Investigation: Funmilayo I. D. Afolayan, Beatrice Irungu
used as an antimalarial agent in humans. The advantage Writing – original draft: Funmilayo I. D. Afolayan
that these plants have over chloroquine is that they are Writing – review & editing: Olayemi Adegbolagun, Jennifer
new, effective, and not associated with known resistance. Orwa, Chiaka Anumudu
The extracts generally exhibited weak to moderate All authors read and approved the final manuscript.
activity in the repository test, with N. latifolia showing high Ethics approval and consent to participate
activity at certain concentrations. However, in the curative
test, the majority of the extracts, especially N. latifolia, The respondents to the ethnobotanical survey
displayed between no to weak activity. The antiplasmodial questionnaires verbally consented to participate in the
effect of M. lucida on established malaria infection in survey. The guidelines provided by the WHO and the
mice showed significant malaria suppression compared to ACUC of KEMRI were adhered to, which outline the
the other extracts. These findings suggest that M. lucida internationally recognized principles for the use and care
could be a better curative agent rather than a prophylactic of laboratory animals.
agent, while other extracts, especially N. latifolia, could be Consent for publication
considered prophylactic agents.
Not applicable.
5 Conclusion
Availability of data
The study investigated the plants used for treating malaria
in Omu Aran Kwara State, Nigeria, and revealed that the Supporting data can be obtained from the corresponding
extracts of M. lucida, N. latifolia, C. odorata, T. diversifolia, author following formal request.

Volume 6 Issue 2 (2023) 14 https://doi.org/10.36922/itps.0300