JOURNAL OF BIOSCIENCE AND BIOTECHNOLOGY DISCOVERY
Integrity Research Journals
ISSN: 2536-7064
Model: Open Access/Peer Reviewed
DOI: 10.31248/JBBD
Start Year: 2016
Email: jbbd@integrityresjournals.org
Evaluation of antiplasmodial activities and synergistic interactions of quinine with root extract of Nauclea latifolia against Plasmodium falciparum
https://doi.org/10.31248/JBBD2026.260 | Article Number: 5C8B8C9F1 | Vol.11 (3) - August 2026
Received Date: 02 May 2026 | Accepted Date: 27 May 2026 | Published Date: 30 August 2026
Authors: Kyahar, I. F.* and Aboh, I. M.
Keywords: Plasmodium falciparum., Antiplasmodial activity, chloroquine-resistant malaria, combination index, drug-extract synergy, Nauclea latifolia, quinine, time-kill kinetics.
Nauclea latifolia is widely used in African traditional medicine for malaria, yet systematic evaluation of its antiplasmodial activity and pharmacodynamic interactions with standard drugs remains limited. This study investigated the in vitro antiplasmodial activity, cytotoxicity, and interaction of the methanol root extract of N. latifolia with quinine. The extract was tested against synchronised Plasmodium falciparum chloroquine-sensitive (3D7) and chloroquine-resistant (Dd2) strains using the SYBR Green I fluorescence assay. Cytotoxicity was assessed on HepG2 and Vero cells (MTT assay). Fixed-ratio combinations of extract and quinine (1:1 and 4:1) were evaluated, and parasite viability was quantified via the parasite lactate dehydrogenase (pLDH) assay. IC₅₀, CC₅₀, selectivity indices (SI), combination indices (CI₅₀), isobologram analysis, and time–kill kinetics were determined. The extract exhibited strong antiplasmodial activity (IC₅₀ = 7.12 µg/mL for 3D7; 9.68 µg/mL for Dd2) and low cytotoxicity (CC₅₀ > 200 µg/mL; SI = 30.7 and 22.6). Combination with quinine demonstrated moderate synergism (CI₅₀ = 0.65), permitting a 40–50% reduction in quinine dose. Time–kill analysis confirmed accelerated parasite clearance and sustained suppression without regrowth in the combination treatment, unlike monotherapies. These findings indicate that N. latifolia root extract is a potent, selective antiplasmodial agent and enhances quinine efficacy through synergistic interaction. The extract shows potential as a chemosensitizing partner in antimalarial combination therapy, supporting its ethnomedicinal use and providing a pharmacological basis for further in vivo and mechanistic studies.
| Abbah, J., Amos, S., Chindo, B., Ngazal, I., Vongtau, H. O., Adzu, B., Farida, T., Odutola, A.A., Wambebe, C., & Gamaniel, K. S. (2010). Pharmacological evidence favouring the use of Nauclea latifolia in malaria ethnopharmacy: Effects against nociception, inflammation, and pyrexia in rats and mice. Journal of Ethnopharmacology, 127(1), 85-90. https://doi.org/10.1016/j.jep.2009.09.045 |
||||
| Atanasov, A. G., Zotchev, S. B., Dirsch, V. M., the International Natural Product Sciences Taskforce & Supuran, C. T. (2021). Natural products in drug discovery: Advances and opportunities. Nature reviews Drug discovery, 20(3), 200-216. https://doi.org/10.1038/s41573-020-00114-z |
||||
| Bekono, B. D., Ntie-Kang, F., Onguéné, P. A., Lifongo, L. L., Sippl, W., Fester, K., & Owono, L. C. (2020). The potential of anti-malarial compounds derived from African medicinal plants: a review of pharmacological evaluations from 2013 to 2019. Malaria Journal, 19, 183. https://doi.org/10.1186/s12936-020-03231-7 |
||||
| Benoit-Vical, F., Valentin, A., Cournac, V., Pélissier, Y., Mallié, M., & Bastide, J. M. (1998). In vitro antiplasmodial activity of stem and root extracts of Nauclea latifolia SM (Rubiaceae). Journal of Ethnopharmacology, 61(3), 173-178. https://doi.org/10.1016/S0378-8741(98)00036-1 |
||||
| British Pharmacopoeia Commission (2025). British Pharmacopoeia 2025. The Stationery Office. | ||||
| Chou, T. C. (2006). Theoretical basis, experimental design, and computerized simulation of synergism and antagonism in drug combination studies. Pharmacological Reviews, 58(3), 621-681. https://doi.org/10.1124/pr.58.3.10 |
||||
| Chou, T. C., & Talalay, P. (1984). Quantitative analysis of dose-effect relationships: the combined effects of multiple drugs or enzyme inhibitors. Advances in Enzyme Regulation, 22, 27-55. https://doi.org/10.1016/0065-2571(84)90007-4 |
||||
| Cos, P., Vlietinck, A. J., Vanden Berghe, D., & Maes, L. (2006). Anti-infective potential of natural products: How to develop a stronger in vitro 'proof-of-concept'. Journal of Ethnopharmacology, 106(3), 290-302. https://doi.org/10.1016/j.jep.2006.04.003 |
||||
| Fidock, D. A., Nomura, T., Talley, A. K., Cooper, R. A., Dzekunov, S. M., Ferdig, M. T., Ursos, L. M. B., Sidhu, A. B. S., Naudé, B., Deitsch, K. W., Su, X.-Z., Wootton, J. C., Roepe, P. D., & Wellems, T. E., & Wellems, T. E. (2000). Mutations in the P. falciparum digestive vacuole transmembrane protein PfCRT and evidence for their role in chloroquine resistance. Molecular Cell, 6(4), 861-871. https://doi.org/10.1016/S1097-2765(05)00077-8 |
||||
| Irungu, B., Okari, E., Nyangi, M., Njeru, S., & Koech, L. (2023). Potential of medicinal plants as antimalarial agents: a review of work done at Kenya Medical Research Institute. Frontiers in Pharmacology, 14, 1268924. https://doi.org/10.3389/fphar.2023.1268924 |
||||
| Iwu, M. M. (2014). Handbook of African medicinal plants (2nd edition). CRC Press. https://doi.org/10.1201/b16292 |
||||
| Newman, D. J., & Cragg, G. M. (2020). Natural products as sources of new drugs over the nearly four decades from 01/1981 to 09/2019. Journal of Natural Products, 83(3), 770-803. https://doi.org/10.1021/acs.jnatprod.9b01285 |
||||
| Pink, R., Hudson, A., Mouriès, M. A., & Bendig, M. (2005). Opportunities and challenges in antiparasitic drug discovery. Nature reviews Drug discovery, 4(9), 727-740. https://doi.org/10.1038/nrd1824 |
||||
| Rasoanaivo, P., Wright, C. W., Willcox, M. L., & Gilbert, B. (2011). Whole plant extracts versus single compounds for the treatment of malaria: synergy and positive interactions. Malaria Journal, 10(Suppl 1), S4. https://doi.org/10.1186/1475-2875-10-S1-S4 |
||||
| Tajbakhsh, E., Kwenti, T. E., Kheyri, P., Nezaratizade, S., Lindsay, D. S., & Khamesipour, F. (2021). Antiplasmodial, antimalarial activities and toxicity of African medicinal plants: a systematic review of literature. Malaria journal, 20, 349. https://doi.org/10.1186/s12936-021-03866-0 |
||||
| Teuscher, F., Gatton, M. L., Chen, N., Peters, J., Kyle, D. E., & Cheng, Q. (2010). Artemisinin-induced dormancy in Plasmodium falciparum: duration, recovery rates, and implications in treatment failure. The Journal of Infectious Diseases, 202(9), 1362-1368. https://doi.org/10.1086/656476 |
||||
| Theodoridis, L., & Carvalho, T. G. (2025). Antimalarial drug resistance and drug discovery: learning from the past to innovate the future. International Journal for Parasitology: Drugs and Drug Resistance, 28, 100602. https://doi.org/10.1016/j.ijpddr.2025.100602 |
||||
| Tona, L., Cimanga, R. K., Mesia, K., Musuamba, C. T., De Bruyne, T., Apers, S., Hernans, N., Van Miert, S., Pieters, L., Totté, J., & Vlietinck, A. J. (2004). In vitro antiplasmodial activity of extracts and fractions from seven medicinal plants used in the Democratic Republic of Congo. Journal of Ethnopharmacology, 93(1), 27-32. https://doi.org/10.1016/j.jep.2004.02.022 |
||||
| Valentin, A., Benoit-Vical, F., Pélissier, Y., Koné-Bamba, D., & Mallié, M. (2000). Antiplasmodial activity of plant extracts used in West African traditional medicine. Journal of Ethnopharmacology, 73(1-2), 145-151. https://doi.org/10.1016/S0378-8741(00)00296-8 |
||||
| Wagner, H., & Ulrich-Merzenich, G. (2009). Synergy research: approaching a new generation of phytopharmaceuticals. Phytomedicine, 16(2-3), 97-110. https://doi.org/10.1016/j.phymed.2008.12.018 |
||||
| Wellems, T. E., & Plowe, C. V. (2001). Chloroquine-resistant malaria. Journal of Infectious Diseases, 184(6), 770-776. https://doi.org/10.1086/322858 |
||||
| White, N. J. (2007). Cardiotoxicity of antimalarial drugs. The Lancet Infectious Diseases, 7(8), 549-558. https://doi.org/10.1016/S1473-3099(07)70187-1 |
||||
| White, N. J. (2008). Qinghaosu (artemisinin): the price of success. Science, 320(5874), 330-334. https://doi.org/10.1126/science.1155165 |
||||
| World Health Organisation (2025). World malaria report 2025: Addressing the threat of antimalarial drug resistance. https://www.who.int/teams/global-malaria-programme/reports/ world-malaria-report-2025. https://doi.org/10.30875/9789287074560 |
||||
Copyright © 2026 Integrity Research Journals. All rights reserved.