Antimalarial Products Research Articles

In vitro antiplasmodial activity of six plants against chloroquine-sensitive and resistant strains of Plasmodium falciparum

Introduction: The effectiveness of the first-line malaria treatment has been affected by drug resistance and adverse side effects leading to a limited number of treatment options. This calls for the search for alternative antimalarial agents. The study evaluated the in vitro antimalarial activity of six plants frequently used in herbal antimalarial products in Ghana against chloroquine-sensitive strain (3D7) and chloroquine-resistant strain (DD2) of Plasmodium falciparum. Method: Aqueous extracts were prepared from the plants by decoction and freeze-dried. A fluorescence-based SYBR Green assay was used to evaluate the antimalarial activity of the extracts against Plasmodium falciparum strains 3D7 and DD2. Also, the cytotoxic e?ects (CC50) of the plant extracts against red blood cells were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) rapid calorimetric assay technique. Results: Alstonia boonei, Cryptolepis sanguinolenta, and Azadirachta indica were the most effective mono-herbal extracts with IC50 of 8.64 ?g/mL, 6.12 ?g/mL, and 5.22 ?g/mL respectively against 3D7 lab strain and 8.47 ?g/mL, 5.12 ?g/mL and 5.22?g/mL respectively against DD2 lab strain. The aqueous extracts of Paullinia pinnata, Citrus aurantiifolia, and Tetrapleura tetraptera exhibited moderate activity against both lab strains with IC50 values of 24.72 ?g/mL, 34.89 ?g/mL and 14.94 ?g/mL respectively against 3D7 strain and 14.84 ?g/mL, 31.01 ?g/mL and14.74 ?g/mL respectively against DD2 strain. All plant extracts exhibited no cytotoxicity against RBC (?100 ?g/mL, except Cryptolepis sanguinolenta with CC50 92.7 ?g/mL). Moreover, except Paullinia pinnata, Citrus aurantiifolia and Tetrapleura tetraptera (with low selectivity index: SI < 10), all the plants displayed a good selectivity index (SI>10). Conclusion: All six frequently used antimalarial plants in monotherapy possess significant antimalarial activity against Plasmodium falciparum (3D7) and (DD2) strains. The data obtained from this study support the folkloric and frequent use of these plants in several herbal antimalarial products on the Ghanaian market.

Cyclic peroxides and analogs: Antibacterial, antimalarial, and cytotoxic marine products from Xisha sponge Diacarnus sp.

A chemical investigation of the dichloromethane extract from the Xisha sponge Diacarnus sp. revealed seven undescribed norterpene cyclic peroxides, named diacarperoxides T–Z, and five unreported related norterpenes, named diacarnoids E–I, and eleven previously reported compounds. The structures of these isolated compounds, including their absolute configurations, were elucidated based on extensive spectroscopic analyses, electronic circular dichroism (ECD) calculations, Snatzke's method, [Rh2(OCOCF3)4]-induced ECD spectra, and modified Mosher's method. Bioassays were performed to assess the antibacterial activity against six pathogenic bacteria, cytotoxicities toward three cancer cell lines, and antimalarial activity against Plasmodium parasites. Most of the cyclic peroxides exhibited substantial antibacterial activity (MIC 1–8 μg/mL). Diacarperoxide W and nuapapuin A showed substantial antimalarial activity with IC50 values of 0.98 and 2.83 μM. Moreover, many compounds exhibited <50% cell survival rates, and IC50 values of 0.22–6.33 μM. The apoptosis assay showed that nuapapuin A induced cancer cell apoptosis in a dose-dependent manner.

Knowledge, compliance, and challenges in anti-malarial products usage: a systematic review of at-risk communities for zoonotic malaria

BackgroundZoonotic malaria is a growing public health threat in the WHO Southeast Asia (SEA) and Western Pacific (WP) regions. Despite vector-control measures, the distribution of Macaque fascicularis and M. nemestrina, and Anopheles mosquitoes carrying non-human simian malaria parasites poses challenges to malaria elimination. The systematic review assesses the literature on knowledge and malaria-preventive practices in zoonotic malaria-affected areas across the WHO SEA and WP, aiming to identify challenges for malaria control.MethodsPeer-reviewed articles published in English, Malay and Indonesian between January 2010 and December 2022 were searched in OVID Medline, Scopus, Web of Science, and Google Scholar. Studies of any design—excluding reviews, conference proceedings, and reports from all WHO SEA and WP countries vulnerable to zoonotic malaria—were included. Backwards-reference screening and thematic analysis were conducted.ResultsAmong 4,174 initially searched articles, 22 peer-reviewed articles met the inclusion criteria. An additional seven articles were identified through backwards-reference screening, resulting in a total of 29 articles for this review. Half of these studies were conducted in Cambodia, Myanmar, Malaysia, and Thailand, mainly in forests and remote communities. The review highlighted inconsistencies in the operationalization of knowledge, and five major themes were identified related to knowledge: causation and transmission, symptoms, treatment, severity and complications, and malaria prevention. While participants generally had some understanding of malaria causation/transmission, minority and indigenous ethnic groups demonstrated limited knowledge and held misconceptions, such as attributing malaria to drinking dirty water. Preventive practices included traditional and non-traditional or modern methods—with a preference for traditional approaches to avoid mosquito bites. Challenges to malaria control included feasibility, cost, and access to healthcare services.ConclusionThis review provides insights into knowledge, local understandings, and preventive practices related to malaria in the WHO SEA and WP regions. The findings highlight the need for future research to explore the knowledge of at-risk communities regarding zoonotic malaria, their perceive threat of the disease and factors exposing them to zoonotic malaria. New strategies must be developed for zoonotic malaria programs tailored to local contexts, emphasizing the significance of community participation, health education, and socio-behavioural change initiatives. It is important to consider the interconnectedness of human health, environmental and non-human primates conservation. Socio-cultural nuances should also be carefully considered in the design and implementation of these programs to ensure their effect tailored to local contexts.

Private sector availability and affordability of under 5 malaria health commodities in selected states in Nigeria and the Federal Capital Territory.

To guarantee uninterrupted service delivery, quality-assured products must be affordable and continuously available across all sectors, including the private sector, which provides more than 60% of healthcare services in Nigeria. We investigated the private sector availability and affordability of under 5 malaria commodities to establish the level of access in this sector. We surveyed patent medicine and pharmacy stores across seven states in Nigeria and the Federal Capital Territory to establish the availability and affordability of selected malaria commodities for children under 5 years. Availability was measured as the percentage of visited outlets with the product of interest on the day of visit, while affordability was assessed by establishing if it cost more than a day's wage for the least-paid government worker to purchase a full course of malaria diagnostic test and/or medication. Artemisinin-based antimalarials for uncomplicated and severe malaria were the most available commodities. SPAQ1 and SPAQ2 used for seasonal malaria chemoprevention campaign were surprisingly also available in some outlets. However, only about half (48.3% and 53.3%) of the surveyed outlets had stock of artemether/lumefantrine (AL1) and artesunate injection, respectively. The median price of surveyed products ranged from USD (United States Dollars) 0.38 to USD 2.17 per treatment/test. Except for amodiaquine tablet and artemether injection, which cost less, all other originator brands cost the same or more than the lowest-priced generic. Antimalarial products were affordable as their median prices were not more than a day's wage for the least-paid government worker. However, when the cost of testing and treatment with artemisinin-based combination therapies (ACTs) was assessed, testing and treatment with dihydroartemisinin/piperaquine were unaffordable as the they cost more than 1.5 times the daily wage of the least-paid government worker. The overall private sector availability of under-five malaria commodities in surveyed locations was suboptimal. Also, testing and treatment with recommended ACTs were not affordable for all surveyed products. These findings suggest the need for interventions to improve access to affordable under-five malaria commodities.

A Review on Medicinal Plants Used as Alternative Treatment for Malaria: An Anti-malarial Drug

Malaria remains an important risk around the globe public health, particularly in tropical and subtropical areas. Malaria, a disease that infects millions of human beings worldwide, is still caused by numerous Plasmodium species, with Plasmodium falciparum being the most virulent and common in sub-Saharan Africa. Pregnant women tend to be at high risk despite great success in lowering malaria-related deaths. This study focuses on using natural antimalarial treatments in Ghana, an economy with a severe malaria epidemic. Communities in Ghana rely on those natural remedies because they perceive them to be efficient and affordable, especially in rural areas. The study's objectives involve figuring out the herbs applied in these preparations, evaluating their scientific validity, and deciding if they correspond to the requirements of the FDA for domestic and foreign marketing. The World Health Organization's World Health Assembly has recognized the elimination of parasitic infections as one of its top goals. The obstacle with current antimalarial drug resistance necessitates people to search for novel treatments. The success rate of various plant-based malaria treatments is looked at in this study. In the end, results indicate the need for additional study in the search for appropriate antimalarial medical products and educate us to understand conventional herbal treatments and their roles in fighting the spread of malaria.

Malaria endemicity: A survey of antimalarial herbal products in Ijebu Ode, Nigeria

Empirical evidence has shown that approximately 80% of the global population uses herbal medicines as primary care, especially in developing nations, particularly Nigeria. Despite this, an estimated 95% of global cases of malaria occur in Africa, with Nigeria accounting for approximately 27%. Therefore, the current study investigated the prevalence of antimalarial herbal medicinal products in Ijebu-Ode for the fight against malaria endemicity. It explored their regulatory registration and active plant components, considering the documented evidence of their use for treating malaria. A cross-sectional study was adopted in the collection of empirical data and analyzed in SPSS (version 23.0), while spatial data were analyzed in ARC-GIS, and the results were graphically presented using pictorial variables. The results revealed the availability of approximately 18 different antimalarial herbal products, of which 72.2% were registered with regulatory agencies. Similarly, the herbal products were shown to contain more than one plant species as their active component (Azadirachta indica (83.3%), Nauclea latifolia (55.6%), and Enantia chlorantia (44.4%), which may be responsible for multiple indications (typhoid (83.3%), yellow fever (38.9%), and cold (33.3%). The results of this study provide valuable insights for developing evidence-based policies to standardize and regulate herbal remedies, particularly for combating malaria and other endemic conditions. These findings have implications for public health and the development of effective strategies to address the challenges posed by malaria in Nigeria and other similar regions.

Antimalarial stocking decisions among medicine retailers in Ghana: implications for quality management and control of malaria

Global health efforts such as malarial control require efficient pharmaceutical supply chains to ensure effective delivery of quality-assured medicines to those who need them. However, very little is currently known...

Sustainable development roadmap of Chinese antimalarial products

As the first country that has been certified malaria-free in the WHO Western Pacific Region for more than 3 decades, China should share its successful experiences of malaria control and provide globally recognized anti-malaria products by making full uses of its advantages in provision and production capacity of artemisinin raw materials, to fill the gaps of international demands for mosquito nets, rapid diagnostic reagents and antimalarial compounds. Increasing the investment of research and development of antimalarial products, building overseas bases for artemisinin raw material production, establishing international regulatory authority and promoting the local production of antimalarial products are needed to further promote the internationalization of Chinese antimalarial products, so as to achieve the equity and accessibility of Chinese antimalarial products in highburden regions for malaria.

Development and Validation of an Ion-Pair HPLC-UV Method for the Quantitation of Quinoline and Indoloquinoline Alkaloids in Herbal and Pharmaceutical Antimalarial Formulations

Quinine- and cryptolepine-based antimalarials serve as valuable alternatives to artemisinin-based combination therapies (ACTs) in Ghana. Their use, however, is associated with adulteration and substandard quality challenges. An HPLC method targeting quinoline and indoloquinoline antimalarial alkaloids was developed, validated, and applied to evaluate herbal and pharmaceutical antimalarial formulations (HPAFs) and starting materials (APIs). The separation/quantitation of the alkaloids (including quinine, quinidine, cinchonine, cinchonidine, dihydroquinine, dihydroquinidine, and cryptolepine) was achieved on a Zorbax SB-CN column (250 mm × 4.6 mm, 5 μm), with an isocratic elution system of methanol: trifluoroacetic acid (0.1%, v/v) (15 : 85, v/v) at 1.5 mL/min and 223 nm. Method validation was according to ICH Q2(R1) guidelines. It was then used to assess the quality of APIs (n = 3) and HPAFs (n = 44) including quinine-based pharmaceutical antimalarial formulations (QBPAFs) (n = 23) and herbal antimalarial products (HAMPs). The method was found to be specific, selective, accurate, precise, and robust toward the alkaloids with linearity achieved within specified concentration ranges (r2 &gt; 0.995 for all analytes). Analyte stability ranged between 6 and 12 hours. All the APIs contained quinine &lt;99.0%–101.0%, with dihydroquinine and cinchonidine at levels compliant with the established acceptance criteria. The QBPAFs had quinine content ranging between 50.2% and 151.2%, with 43.5% (n = 10/23) of them complying with the acceptance criteria. The related alkaloids observed in the QBPAFs included quinidine (56.5%, n = 13/23), dihydroquinine (100%, n = 23/23), dihydroquinidine (21.7%, n = 5/23), cinchonine (17.4%, n = 4/23), and cinchonidine (95.7%, n = 22/23). For the HAMPs, 81.0% (n = 17/21) were adulterated with quinine (0.59 ± 0.04 mg/10 mL–86.03 ± 0.02 mg/10 mL). Cryptolepine was identified in 19% (n = 4/21) of the HAMPs with concentration ranging between 43.99 ± 0.43 μg/mL and 747.86 ± 0.34 μg/mL. In conclusion, the application of the ion-pair HPLC method targeting quinoline and indoloquinoline antimalarials has demonstrated the presence of quality and poor-quality HPAFs on the Ghanaian market.

Safety evaluation of an antimalarial herbal product from Andrographis paniculata (AS201-01) in healthy volunteers.

Andrographis paniculata tablets (AS201-01) have previously been shown to have potent bioactivity as an antimalarial and to produce no unwanted side effects in animal models. Here, we present the phase 1 clinical trial conducted to evaluate the safety of AS201-01 tablets in healthy volunteers. The study was a randomized, double-blind controlled cross-over, a placebo-controlled design consisting of a 4-day treatment of AS201-01 tablets. A total of 30 healthy human volunteers (16 males and 14 females) were divided into two groups, and each group was given 4 tablets, twice daily for 4days. Group 1 received AS201-01, while group 2 received placebo tablets. Volunteers were given a physical examination before the treatment. The effects of AS201-01 on random blood glucose, biochemical, and hematological as well as urine profiles were investigated. There were no changes in observed parameters as a result of AS201-01 being administered. Statistical analysis showed no significant difference (p>0.05) between the test and control group regarding hematology profile, biochemical profile, and random blood glucose. Increased appetite and better sleep, which categorized as grade 1 adverse event was reported after treatment with AS201-01 tablet. The outcome supports our previous observation that the AS201-01 tablet, given twice a day for 4 days, is safe and nontoxic.

A Review on Development and Characterization of a Cost-effective Targeted Quality-driven Antimalarial Product with an Emphasis on Phytosomes.

Malaria, a protozoan disease, led to numerous deaths and several new million cases raised due to the development of resistance as per the WHO malaria report 2019. This can be overcome by the development of an effective targeted plant-based delivery system through phytosomes that are effective in permeation and bioavailability to treat infected RBCs (parasitic cells). This review article explained the development of targeted Nanophytosomes to overcome resistance, to improve efficacy. This review paper also emphasized various quality-driven developmental approaches in developing an antimalarial product at a reasonable cost. By implementing molecular modeling techniques in development, a significant phytoconstituent with the capability of acting at the target (receptor or enzymes) of the parasite and the one with the capability to overcome drug resistance against resistant strains of parasites can be identified. Absorption Distribution Metabolism Excretion and Toxicity (ADMET) studies information provide a route to the design and formulation of a potent antimalarial agent. Efficient, targeted Nanophytosomal formulations can be formulated by functionalizing or conjugating with suitable targets to direct the phytoconstituent to the infected RBCs thereby achieving complete parasitic eradication. Artificial Neural Network technology (ANN), Quality by Design (QbD), molecular dynamics, and simulation studies implementation improves quality and reduces the cost of the product, as these malarial products are much utilized in low-income countries. Hence it can be concluded that targeted developmental quality-driven approaches implementation is essential for effective malarial treatment.

In vitro and in vivo Activity of Mist Amen Fevermix and Edhec Malacure, Polyherbal Antimalarial Products on Field Isolates of Plasmodium falciparum and Plasmodium berghei

BackgroundMalaria is a life-threatening infectious disease, which pose a public health challenge. Currently, reports of parasites resistance to artemisinin-based combination therapies is widespread. This has renewed calls for new antimalarial medications including  herbal products for the treatment of malaria. This study was undertaken to scientifically assess the antiplasmodial potentials of Mist Amen Fevermix and Edhec Malacure, two polyherbal antimalarial products used for the management of uncomplicated malaria, and establish their phytochemical constituents.MethodsQualitative phytochemical screening based on standard analytical methods. The antiplasmodial activity was assessed in vitro by using Plasmodium falciparum. The SYBR® Green assay was used to measure parasite growth inhibition. In vivo activity was assessed with Plasmodium berghei parasites using the Rane’s curative method with artesunate as positive control.ResultsThe phytochemical screening of the products revealed the presence of alkaloids, flavonoids, tannin, steroid and saponin. In the in vitro studies, the IC50 values for Edhec Malacure was 70.89 ng/mL and 112.5ng/mL for Mist Amen Fevrmix. Artesunate exhibited an IC50 value of 1.571ng/mL. Edhec Malacure suppressed parasitemia by 76.17% (at 4.25mg/kg-1) and Mist Amen Fevermix by 69.03% (at 1.56 mg/kg-1) in vivo.  ConclusionMist Amen Fevrmix and Edhec Malacure Mixture demonstrated antiplasmodial activity and may be useful alternative antimalarial agents.Â

Characterization of solid lipid dispersions prepared by hot fusion containing a double-fixed dose combination of artemether and lumefantrine

Objective The World Health Organization has called for the development of novel drug delivery systems to combat malaria – the fourth most prevalent cause of death globally. The plausibility of utilizing hot fusion to prepare solid lipid dispersions containing the prescribed first-line, double-fixed dose combination (artemether and lumefantrine), proposed for inclusion in directly compressed lipid matrix tablets, was investigated. Significance: Currently, no anti-malarial product is commercially available that employs lipid technology in a solid oral dosage form that contains this double-fixed dose combination. Through developing lipid matrix tablets, the stability, solubility and subsequent bioavailability of these drugs could be significantly enhanced in the presence of lipids or oils. Methods Hot fusion encompasses encompassed melt mixing of a selected lipid base and the dispersion of the active ingredient(s) therein below their glass transition temperatures. Solid-state characterization, particle size analysis and pharmacotechnical properties were evaluated, with particular focus given to powder flowability. Results Stearic acid in a 0.5:1 lipid:drug ratio demonstrated the best powder flow properties of the investigated solid lipid dispersion for inclusion into prospective lipid–matrix tablets duly based on an increase in overall particle size, a more spherical particle shape and improved powder flow properties compared to the individual active ingredients. Conclusion Good powder flow is critical for powders destined for inclusion into tablets – especially when employing direct compression as method of manufacture – in this case, lipid matrix tablets, which have demonstrated huge promise as a prospective dosage form for future use in malarial treatment.

An old drug as a promising new cure for the hard-to-treat echinococcosis

An old drug as a promising new cure for the hard-to-treat echinococcosis

Evaluation of the Microbial Load and Heavy Metal Content of Two Polyherbal Antimalarial Products on the Ghanaian Market.

The use of herbal products has increased and become more popularized globally; however, limited studies coupled with questions related to the quality and safety of these herbal products have been raised. Herbal products with hope of their nontoxicity may play a role of alternative to overcome the problems of multi-drug resistant pathogens. Medicinal plants used as raw materials for production may have quality and safety issues due to proximity to wastewater application of fungicides and pesticides, which may be directly deposited superficially or absorbed by the plant system. Therefore, possible contamination of some Ghanaian herbal products cannot be ignored, as it may severely affect human life in the process of treatment. Aim. To evaluate the microbial load and the presence of toxic heavy metals in Mist Amen Fevermix and Edhec Malacure, two polyherbal products used in the treatment of uncomplicated malaria in Ghana. Methods. Thermo Elemental M5 Atomic Absorption Spectrophotometer (AAS) fitted with graphite furnace and an auto sampler was used to determine the heavy metal contents of the herbal products. The herbal samples were evaluated for the microbial load by using the appropriate culture media. Results and Analysis. Mist Amen Fevermix and Edhec Malacure complied with the safety limits evaluated for all different microbial counts and contamination. The following heavy metals were present in Mist Amen Fevermix and Edhec Malacure Mixture: Fe, Ni, K, Zn, Hg, Cu, Mn, Cr, Cd, Pb, Fe, Cu, K, and Na. Ni was below detectable limit in Edhec Malacure. Conclusion. Mist Amen Fevermix and Edhec Malacure may be assured of safety. The products contained heavy metals, but all were within acceptable limit established by the FAO/WHO. The levels of microbial contamination were below the maximum acceptable limit.

Influence of MAMA decoction, an Herbal Antimalarial, on the Pharmacokinetics of Amodiaquine in Mice.

MAMA decoction (MD) is an antimalarial product prepared from the leaves of Mangifera indica L. (Anacardiaceae), Alstonia boonei De Wild (Apocynaceae), Morinda lucida Benth (Rubiaceae) and Azadirachta indica A. Juss (Meliaceae). A previous report showed that MD enhanced the efficacy of amodiaquine (AQ) in malaria-infected mice, thus suggesting a herb-drug interaction. The present study hence evaluated the effect of MD on the disposition of AQ in mice with a view to investigating a possible pharmacokinetic interaction. In a 3-period study design, three groups of mice (n = 72) were administered oral doses of AQ (10mg/kg/day) alone, concurrently with MD (120mg/kg/day), and in the 3rd period, mice were given AQ after a 3-day pre-treatment with MD. Blood samples were collected between 0 and 96h for quantification of AQ and its major metabolite, desethylamodiaquine, by a validated high-performance liquid chromatography method. Maximum concentrations of AQ increased by 12% with the concurrent dosing of MD and by 85% in the group of mice pre-treated with MD. The exposure and half-life of desethylamodiaquine increased by approximately 11% and 21%, respectively, with concurrent administration. Corresponding increases of approximately 20% and 33% of desethylamodiaquine were also observed in mice pre-treated with MD. MD influenced the pharmacokinetics of AQ and desethylamodiaquine, its major metabolite. The increase in the half-life and systemic exposure of AQ following its co-administration with MD may provide a basis for the enhanced pharmacological effect of the combination in an earlier study in Plasmodium-infected mice.

Intestinal permeability studies for piperaquine from dihydroartemisinin—piperaquine antimalarial product in the presence of lamivudine

Intestinal permeability studies for piperaquine from dihydroartemisinin—piperaquine antimalarial product in the presence of lamivudine

Antimalarial Efficacy and Chemopreventive Capacity of Bamboo Leaf (&lt;i&gt;Bambusa vulgaris&lt;/i&gt;) in Malaria Parasitized Mice

The exploration of natural products for the treatment of malarial has been the main focus of scientists in the past decades. In this research, the phytochemical constituents, antimalarial effect, and chemopreventive capacity of aqueous leaf extract of Bambusa vulgaris in malaria parasitized mice was investigated. A total of 30 male mice, grouped into six (n=5), was used. The results obtained showed that B. vulgaris is rich in flavonoid (262.08 μg CE/g) and phenol (0.91 g AAE/ 100 g). There was significant reduction on the activities of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and Gamma glutarmyl-transferase (GGT) upon treatment as compared with the control groups (P&lt;0.05). Concentration of total bilirubin (TB), direct bilirubin (DB) and serum electrolytes (sodium, calcium, phosphorus and chloride) decreased in treated groups; serum urea, creatinine and uric acid also reduced significantly as against the control groups (P&lt;0.05). The hepatoprotection and renal function restoration observed upon the administration of the plant extract indicate to a far reaching end that B. vulgaris leaf extract would be a promising natural antimalarial product devoid of side effects upon use, especially when administered within the dose range of 100 – 200 mg/Kg body weight investigated in this study.Keywords: Bambusa vulgaris, phytochemicals, antimalarial, chemoprevention.

Optimization of artemisinin extraction from Artemisia annua L. with supercritical carbon dioxide + ethanol using response surface methodology.

Malaria is a high priority life-threatening public health concern in developing countries, and therefore there is a growing interest to obtain artemisinin for the production of artemisinin-based combination therapy products. In this study, artemisinin was extracted from the Artemisia annua L. plant using supercritical carbon dioxide (SC-CO2 ) modified with ethanol. Response surface methodology based on central composite rotatable design was employed to investigate and optimize the extraction conditions of pressure (9.9-30 MPa), temperature (33-67°C), and co-solvent (ethanol, 0-12.6 wt.%). Optimum SC-CO2 extraction conditions were found to be 30 MPa and 33°C without ethanol. Under optimized conditions, the predicted artemisinin yield was 1.09% whereas the experimental value was 0.71 ± 0.07%. Soxhlet extraction with hexane resulted in higher artemisinin yields and there was no significant difference in the purity of the extracts obtained with SC-CO2 and Soxhlet extractions. Results indicated that SC-CO2 and SC-CO2 +ethanol extraction is a promising alternative for the extraction of artemisinin to eliminate the use of organic solvents, such as hexane, and produce extracts that can be used for the production of antimalarial products.

Insight into clinically effective herbal antimalarial products: Effects on drug metabolizing enzymes and p-glycoprotein

Malaria is a leading cause of morbidity and mortality in many developing tropical countries, particularly in children and pregnant women. With growing concerns about the development of resistance to current antimalarial drugs, herbal alternatives may provide significant and sustainable treatment options in affected regions. This review aimed at providing an updated overview of available data on Herbal Medicinal Products (HMPs) with reproducible evidence-based antimalarial efficacies. In addition, it identified the antiplasmodial phyto-constituents and discussed the potential of these products to modulate activities of drug metabolizing enzymes and drug transport systems. This is particularly important because the co-morbidity of malaria with other diseases, often prevalent in malaria endemic regions, is marked by a concurrent use of herbal antimalarial products with conventional drugs. An extensive literature search was undertaken and the information obtained were critically analysed. Enormous work has been reported on investigations of the antiplasmodial activity of herbs, and more than 1000 plants have been studied using in vitro and animal malaria infection models. However, only a few of these HMPs have been subjected to randomized clinical trials. Herb-drug interactions are of great concern since phytochemical compounds in HMPs are subject to the same pharmacokinetic processes that determine the fate of synthetic drugs in the human body. Thus, specific effects of these clinically effective antimalarial HMPs on drug metabolizing enzymes were reported with a view to documenting information for optimization of their therapeutic utility. Beneficial and adverse clinically significant interactions were also identified for close therapeutic attention. Key words: Antimalarial herbal products, evidence-based efficacy, cytochrome P450, herb-drug interactions.