The In Vitro Antiplasmodial Activities of Aqueous Extracts of Selected Ghanaian Herbal Plants

A scoping review of the use of traditional medicine for the management of ailments in West Africa

BACKGROUND

The coexistence of traditional healing practices deeply rooted in cultural and historical contexts and the evolving landscape of modern healthcare approaches in West African societies creates a dynamic interplay between tradition and modernity in healthcare. This study aims to comprehensively map the landscape of traditional medicine use for health in West Africa.

METHODS

A scoping review was conducted following the Joanna Briggs Institute (JBI) methodology and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) guidelines. Research questions focused on the links between traditional medicine practices and health in West Africa. The systematic literature search covered PubMed, Web of Science, and CINAHL from database inception to September 2023. A descriptive analysis was conducted highlighting the years of publication, countries of publication, study designs of plant families and plant parts used for making traditional medicines, and the diseases the traditional remedies are for.

RESULTS

The search identified 3484 records, with 46 articles meeting the inclusion criteria. Publications spanned from 1979 to 2023, with no observed trend in the number of publications over successive decades. Nigeria had the highest number of publications (54.3%), followed by Ghana (19.6%). The studies employed various designs, including clinical trials, ethnobotanical, ethnopharmacological, and experimental designs. Plant families frequently studied included Combretaceae, Euphorbiaceae, and Rubiaceae. Traditional remedies address various health issues, highlighting their versatility, from general symptoms to specific diseases.

CONCLUSION

This scoping review offers an extensive overview of traditional healing practices in West Africa. The studies highlighted in this review stress the necessity for culturally sensitive healthcare interventions. The widespread use of traditional medicine and the variety of practices underscore the importance of encouraging collaboration between traditional healers and modern healthcare professionals. This review also identifies knowledge gaps and areas needing further research, setting the stage for future exploration into West Africa's intricate healthcare landscape.

Research on Moringa (Moringa oleifera Lam.) in Africa

While Moringa oleifera Lam. is gaining importance in Africa, especially sub-Saharan Africa, it is unclear whether research is following the quick pace of its development on the continent. Therefore, this article analyzes the landscape of research dealing with moringa in Africa. This systematic review draws upon 299 eligible articles identified through a search carried out on the Web of Science in April 2023. Research on M. oleifera is rather recent in Africa but interest is increasing among scholars. While the research field is multidisciplinary and cross-sectoral, the literature seems to focus on biological and environmental sciences. Moreover, research is performed mainly in South Africa, Nigeria, Egypt, and Ghana. The analysis suggests a significant potential contribution of moringa to food security and nutrition, climate change mitigation/adaptation, farming systems resilience, and livelihoods. Its versatility and diverse applications and uses make moringa particularly interesting for developing countries, such as African ones. However, this review also underscores some factors hindering its development. Therefore, there is a need to strengthen research on moringa to unlock its potential in Africa. Investments in research, innovation, and development can help address the many challenges that Africa faces and contribute to the transition towards sustainable and resilient food systems.

Geo-environmental factors and the effectiveness of mulberry leaf extract in managing malaria

Malaria prevalence has become medically important and a socioeconomic impediment for the endemic regions, including Purulia, West Bengal. Geo-environmental variables, humidity, altitude, and land use patterns are responsible for malaria. For surveillance of the endemic nature of Purulia's blocks, statistical and spatiotemporal factors analysis have been done here. Also, a novel approach for the Pf malaria treatment using methanolic leaf extract of Morus alba S1 has significantly reduced the parasite load. The EC50 value (1.852) of the methanolic extract of M. alba S1 with P. falciparum 3D7 strain is close to the EC50 value (0.998) of the standard drug chloroquine with the same chloroquine-sensitive strain. Further studies with an in-silico model have shown successful interaction between DHFR and the phytochemicals. Both 1-octadecyne and oxirane interacted favourably, which was depicted through GC-MS analysis. The predicted binary logistic regression model will help the policy makers for epidemiological surveillance in malaria-prone areas worldwide when substantial climate variables create a circumstance favourable for malaria. From the in vitro and in silico studies, it can be concluded that the methanolic extract of M. alba S1 leaves were proven to have promising antiplasmodial activity. Thus, there is a scope for policy-driven approach for discovering and developing these lead compounds and undermining the rising resistance to the frontline anti-malarial drugs in the world.

Plant Extracts as a Source of Natural Products with Potential Antimalarial Effects: An Update from 2018 to 2022

Malaria kills more than 500,000 people yearly, mainly affecting Africa and Southeast Asia. The disease is caused by the protozoan parasite from the genus Plasmodium, with Plasmodium vivax and Plasmodium falciparum being the main species that cause the disease in humans. Although substantial progress has been observed in malaria research in the last years, the threat of the spread of Plasmodium parasites persists. Artemisinin-resistant strains of this parasite have been reported mainly in Southeast Asia, highlighting the urgent need to develop more effective and safe antimalarial drugs. In this context, natural sources, mainly from flora, remain underexplored antimalarial spaces. The present mini-review explores this space focusing on plant extracts and some of their isolated natural products with at least in vitro antiplasmodial effects reported in the literature comprising the last five years (2018-2022).

A review of efficacy and safety of Ugandan anti-malarial plants with application of RITAM score

BACKGROUND

Malaria, a treatable disease mainly caused by Plasmodium falciparum has remained a health challenge in Africa, a continent that accounted for 96% of total global cases and deaths in 2021. Uganda, a malaria endemic country is experiencing malaria parasite resistance to some of the drugs used in the artemisinin-based combination therapy (ACT). In an effort to prioritize herbal medicines for new product development, this review synthesized the available safety and efficacy literature on the Ugandan anti-malarial plants to suggest most effective herbal plants.

METHODS

Literature was exhaustively searched using engines and databases, such as Google scholar, Pubmed, and Scopus-indexed journals during the period of June 2020-December 2021. In the first phase, information on ethnobotanical uses of anti-malarial plants in Uganda was gathered and synthetized to generate a list of plants, followed by data on anti-malarial efficacy (both in vitro and in vivo) on each listed plant. Minimum inhibitory concentrations (µg/ml), and % parasite suppression for every plant were scored using The Research Initiative on Traditional and Antimalarial Methods (RITAM) scoring system. The best twenty (20) plants were evaluated for acute safety (LD₅₀) data in rat model, plant parts used, ease of cultivation, presence of clinical studies and other relevant factors for suggesting the best three (3) plants for future anti-malarial product development.

RESULTS

Over one hundred twenty-six (126) plant species are used in Uganda for treatment of malaria in local communities. Out of these, about 33% (41) have been studied for efficacy and safety, with Artemisia annua and Vernonia amygdalina being the most extensively studied and among the best twenty (20) anti-malarial plants in Uganda. Both are limited by parasite recrudescence in clinical studies. Microglossa pyrifolia, a very potent plant (IC50 = 0.03 - 0.05 µg/ml has potential to penetrate the liver and could ameliorate the challenge of recrudescence if combined with A. annua and V. amygdalina in a polyherbal formulation.

CONCLUSION

There are many plants with promising potential for malaria treatment in Uganda and a herbal combination of A. annua, V. amydalina and M. pyrifolia could offer the next herbal ACT if carefully studied and developed.

Synthesis of new series of quinoline derivatives with insecticidal effects on larval vectors of malaria and dengue diseases

Mosquito borne diseases are on the rise because of their fast spread worldwide and the lack of effective treatments. Here we are focusing on the development of a novel anti-malarial and virucidal agent with biocidal effects also on its vectors. We have synthesized a new quinoline (4,7-dichloroquinoline) derivative which showed significant larvicidal and pupicidal properties against a malarial and a dengue vector and a lethal toxicity ranging from 4.408 µM/mL (first instar larvae) to 7.958 µM/mL (pupal populations) for Anopheles stephensi and 5.016 µM/mL (larva 1) to 10.669 µM/mL (pupae) for Aedes aegypti. In-vitro antiplasmodial efficacy of 4,7-dichloroquinoline revealed a significant growth inhibition of both sensitive strains of Plasmodium falciparum with IC50 values of 6.7 nM (CQ-s) and 8.5 nM (CQ-r). Chloroquine IC50 values, as control, were 23 nM (CQ-s), and 27.5 nM (CQ-r). In vivo antiplasmodial studies with P. falciparum infected mice showed an effect of 4,7-dichloroquinoline compared to chloroquine. The quinoline compound showed significant activity against the viral pathogen serotype 2 (DENV-2). In vitro conditions and the purified quinoline exhibited insignificant toxicity on the host system up to 100 µM/mL. Overall, 4,7-dichloroquinoline could provide a good anti-vectorial and anti-malarial agent.

The Effectiveness of Varying Combination Ratios of A. cordifolia and M. indica against Field and Laboratory Strains of P. falciparum In Vitro

Background

Drug resistance in malaria is a global problem, with reports of Plasmodium parasites resistant to the current first-line antimalarial drug, artemisinin, expanding from Southeast Asia to Africa. There is therefore an urgent need to identify new drug candidates that will be effective against the existing malaria parasites. Drug combination therapy presents a myriad of advantages over monotherapy including delayed onset of resistance, potentiation, and synergism. This present study explored the effectiveness of combinations of aqueous extracts of Alchornea cordifolia (A. cordifolia) and Mangifera indica (M. indica) at clearing both laboratory and field isolates of P. falciparum.

Methods

Synchronized ring stage cultures of field (FA08) and laboratory strains (NF54 and CamWT_C580Y) of P. falciparum were subjected to combinations of different concentrations and ratios of aqueous extracts of A. cordifolia and M. indica. The growth inhibition of the individual plant extracts and their combinatory effects were studied in vitro using SYBR Green I drug assay.

Results

The A. cordifolia extract exhibited 50% inhibitory concentration (IC₅₀) of 2.71, 7.80, and 3.56 μg/mL against the NF54, CamWT_C580Y, and FA08 parasite strains, respectively. Mangifera indica exhibited IC₅₀ of 18.11, 20.08, and 10.23 μg/mL against the NF54, CamWT_C580Y, and FA08 parasite strains, respectively. Additive, synergistic and antagonistic interactions were observed at different combinations of A. cordifolia and M. indica extracts.

Conclusion

A combination product containing A. cordifolia and M. indica has the potential to serve as an effective antimalarial as majority of the tested combinations of aqueous extracts of A. cordifolia and M. indica extracts exhibited synergistic effects in vitro against the NF54, CamWT_C580Y, and FA08 P. falciparum strains.