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Ethnopharmacological Relevance: Phyllanthus muellerianus (Kunze) Exell, a member of the Phyllanthaceae family, is a medicinal plant widely distributed in Africa. Decoctions from the leaves are used in Nigeria to treat fevers, convulsions, some neurological disorders and malaria., Aim of the Study: This study is to evaluate the anti-malarial properties of methanol extract of Phyllanthus muellerianus (MEPM) leaves and its ethyl acetate fraction using a murine malaria model infected with Plasmodium berghei. Additionally, we seek to investigate the potential modulatory effects of this extract and fraction on CD4 + T-cell populations in the context of malaria infection., Materials and Methods: The anti-malarial effects of the leaf methanol extract of Phyllanthus muellerianus (MEPM) were screened using three established in vivo models of anti-plasmodial screening namely the curative, suppressive and prophylactic models. The methanol extract (MEPM) was afterwards fractionated into hexane (HFPM), ethyl acetate (EAFPM), and methanol (MFPM) fractions. In the pilot anti-malarial screening of the fractions, EAFPM exhibited the best antiparasitic activity. Subsequently, EAFPM was screened for anti-malarial activity using the three models above. The effects of the MEPM and EAFPM on haematological indices (Hb and PCV) of the inoculated animals were further screened and the mean survival time (MST) of the animals was monitored. CD4 + T cells of various groups were counted before and after treatment using a flow cytometer. The EAFPM was further subjected to HPLC analysis for identification of its major compounds., Results: The EAFPM (100 and 200 mg/kg) elicited 88% and 93% cure respectively in the curative model, while artesunate (5 mg/kg,- the positive control) gave 87% protection. The MEPM and EAFPM also gave significant suppression of parasitemia in the suppressive model. The treated groups survived beyond 28 days as against 11 days by the control group (infected but not treated). The treated groups also prevented anaemia seen in the negative control. The EAFPM group significantly modulated the CD4 + T cell. Compounds identified were Gallocatechin, Quercetin -3-O-gallate, Ellagic acid, and Methylellagic acid rhamnoside)., Conclusion: The study established that the leaf of Phyllanthus muellerianus possesses antimalarial activity, thus lending support to its use in the folkloric treatment of malaria., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Ethnopharmacological Relevance: Plasmodium falciparum multi-drug resistant (MDR) strains are a great challenge to global health care. This predicament implies the urgent need to discover novel antimalarial drugs candidate from alternative natural sources. The Himalaya constitute a rich repository of medicinal plants which have been used traditionally in the folklore medicine since ages and having no scientific evidence for their activity. Crambe kotschyana Boiss. and Eremurus himalaicus Baker are used for their antipyretic and hepatoprotective properties in Kinnaur district of Himachal Pradesh, India., Aim of the Study: This study would investigate the antiplasmodial efficacy of C. kotschyana and E. himalaicus extracts, their fractions and active components using in vitro, in vivo and in silico approaches to provide a scientific insight into their activity., Methods: The methanol extracts of C. kotschyana (CKME) and E. himalaicus (EHME) were prepared by maceration followed by fractionation using ethyl acetate. The isolation of flavonoid glycosides isorhamnetin-3, 7-di-O-glucoside from C. kotschyana and luteolin-6-C-glucoside (isoorientin) from E. himalaicus was carried out by antiplasmodial activity-guided isolation. In vitro antimalarial activity was assessed by WHO method while in vitro cytotoxicity was ascertained employing the MTT assay. Molecular docking and molecular dynamics simulation were performed using the Glide module of Schrödinger Software and Gromacs-2022 software package respectively. In vivo curative activity was assessed by Ryley and Peters method., Results: The methanol extracts of both the plants illustrated the best antiplasmodial activity followed by the ethyl acetate fractions. Iso-orientin (IC 50 6.49 μg/ml) and Isorhamnetin-3,7-di-O-glucoside (IC 50 9.22 μg/ml) illustrated considerable in vitro activity even against P. falciparum resistant strain. Extracts/fractions as well as the isolated compounds were found to be non-toxic with CC 50  > 640 μg/ml. Molecular docking studies were performed with these 2 O-glucosides against four malaria targets to understand the binding pose of these molecules and the results suggested that these molecules have selectivity for lactate dehydrogenase enzyme. CKME and EHME exhibited curative activity in vivo along with increase in Mean Survival Time of mice., Conclusion: The research delineated the scientific evidence that both the therapeutic herbs possessed antimalarial activity and notably, bioactive compounds responsible to exhibit the antimalarial activity have been isolated, identified and characterized. Further studies are underway to assess the antiplasmodial efficacy of isolated compounds alone and in combination with standard antimalarials., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Ethnopharmacological Relevance: Having identified Annickia affinis as the most potent antiplasmodial plant constituent in a hepta-herbal Agbo-iba (HHA) formula commonly used to manage malaria in Benin city, Nigeria, we have in this study attempted to identify the specialized metabolites responsible for antiplasmodial activity of A. affinis through anti-blood stage malaria parasite activity guided isolation of potent molecules from its stem bark methanol extract. After that, phenotypic effects, including stage-specific kill kinetics, were investigated. Further, the crude extract, its potent fractions, and specialized metabolites were also tested against the liver-stage malaria parasite., Materials and Methods: A. affinis was subjected to molecular PCR-based analysis to confirm its identity. Thereafter, extraction of its stem bark with methanol was carried out. Alkaloid enriched fractions from this stem bark extract were obtained using the acid-base-solvent extraction method. These alkaloid-enriched fractions were subjected to various chromatographic techniques that led to the isolation of two protoberberine alkaloids identified as berberine and palmatine based on NMR and mass spectrometry analysis. The efficacy of crude extract, fractions and purified alkaloids was tested against the malaria parasite's blood and liver stages, respectively., Results and Discussion: Annickia affinis methanol extract, fractions, and the isolated protoberberine alkaloids showed excellent antiplasmodial activity with good selectivity against blood-stage malaria parasite. Thus, their IC 50 against various strains of the parasite ranged from 0.95 to 18.65 μg/ml, while CC 50 against Human embryonic kidney (HEK) and the human hepatoma (HUH-7) cell lines ranged between 10 and > 100 μg/ml. Interestingly, the crude extract and the alkaloid enriched fractions showed promising activity against the liver-stage malaria parasite. Between berberine and palmatine isolated from the potent fractions, only the former showed ∼100% and 90% inhibitions of liver stage parasite at 5 μg/ml and 1 μg/ml, respectively, while the latter showed no inhibition even at 20 μg/ml., Conclusion: This study reports that the ethnomedicinal use of HHA to manage malaria can be attributed to the presence of promising antiplasmodial protoberberine alkaloids together with synergistic effects via either enhancement of bioavailability or improved pharmacokinetics by other phytoconstituent(s) coming from other HHA constituent plants. The protoberberine alkaloids isolated have been identified as fast-acting antiplasmodial agents, with activity against all erythrocytic stages of the malaria parasite. Further, A. affinis methanol stembark extract and the protoberberine alkaloid berberine isolated from it also displayed excellent activity (>90% inhibition at 1 μg/ml) against the liver-stage malaria parasite. A. affinis and HHA can thus be useful as both liver-stage prophylactic and blood-stage curative agents., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Malaria is still one of the most severe public health problems worldwide. The development of treatment, prevention, and control of malaria is one of the substantial problems in the world., Aims: To investigate the in vitro antimalarial activity of Syzygium cumini methanol fruit fraction., Methods: Syzygium cumini L fruit powder was macerated with methanol (PA) and the extract obtained was fractionated using the liquid-liquid partition method with n-hexane, ethyl acetate, butanol, chloroform, methanol, and water solvents. In vitro antimalarial assay was conducted using the culture of Plasmodium falciparum 3D7 strain culture that had reached >5% growth and was examined for IC 50 values using a 24-well microplate in duplicate. Each treatment and control well contained 1,080 μl of complete media. Well, number 1 was added with 120 μl fraction, and then the solution was diluted until it reached 0.01, 0.1, 1, 10, and 100 μg/ml the final concentration in the microtiter well. The control only contained complete media and infected erythrocytes without the addition of anti-malarial drugs. The microplate was incubated for 48 hours. After 48 hours, a thin blood smear was made fixed with methanol and stained with 20% Giemsa for 20 minutes to determine the IC 50 value by plotting sample concentrations and percentage of parasitemia in Excel., Results: The IC 50 values of ethyl acetate fraction, n.hexane fraction, butanol fraction, and water fraction were 1.189, 76.996, 1,769, and 15.058 μg/ml, respectively. Whereases the IC 50 values of C1 fraction (mix fraction from chloroform: methanol 100:0 and 90:10) and C4 fraction (mix fraction from chloroform: methanol 20:80, 10:90, and 0:100) were 100.126 and 1.015 μg/ml, respectively. The results showed that the IC 50 value of ethyl acetate, butanol, and C4 fraction were lower than 10μg/ml and were considered as good activity (strong antimalarial activity)., Conclusion: The ethyl acetate, butanol and C4 subfraction from S. cumini fruit have the potential to be developed as an antimalarial agent., Competing Interests: The authors declare that there is no conflict of interest.

Ethnopharmacological Relevance: The Vha-Venda people of South Africa use Pappea capensis EckI & Zeyh. (Sapindaceae) twigs to treat malaria and its related symptoms., Aim of Study: The main aim of this study was to evaluate the antiplasmodial and cytotoxic activity of P. capensis extracts and chromatographic fractions. Spectroscopy analysis was conducted using 1 H NMR and GC-MS to tentatively identify the major classes of compounds and phytoconstituents that can be attributed to the observed antiplasmodial bioactivity., Materials and Methods: Pappea capensis twigs were dried and then ground to fine powder. A solvent mixture of dichloromethane: methanol: water (1:0.5:0.5, v/v) was used to extract. The polar extract was separated from the non-polar. The organic extract was dried to yield a DCM (I = 60 g) extract. The methanol in the aqueous extract was evaporated using a rotary vapour and the remaining water freeze dried to yield a water extract (II = 287 g). Extract I was further partitioned using a solvent mixture of DCM: MeOH (1:1, v/v), separated and concentrated under vacuum to yield dichloromethane (III = 40 g) and methanol (IV = 15 g) extracts. A water-based decoction (V = 10 g) was also prepared to establish the clinical relevance of the preparation administered by Vha-Venda people in South Africa. Extracts II, III and IV were further subjected to silica column chromatography, eluting with a series of different solvents with increasing polarity to yield a total of 25 fractions (A - Y). In vitro antiplasmodial tests on Plasmodium falciparum (NF54) and cytotoxicity screens on mammalian L-6 rat skeletal myoblast cells were performed on all extracts and fractions. Selectivity indices (SI) were also computed for all tested extracts and fractions which were further subjected to 1 H NMR spectroscopy and GC-MS analysis for the identification of the major classes of compounds present in the extracts., Results: From the assayed extracts, only extract I (IC 50  = 2.93 μg/ml; SI = 14), III (IC 50  = 2.59 μg/ml; SI = 21) and IV (IC 50  = 3.56 μg/ml; SI = 13) demonstrated the best antiplasmodial activity and selectivity. Of all assayed fractions, only N (0.6 μg/ml; SI = 91), D (0.85 μg/ml; SI = 37) and E (0.91 μg/ml; SI = 30) depicted the best antiplasmodial activity and selectivity. The 1 H NMR analysis of the extracts and fractions identified the prominent class of constituents to be aliphatic based which was tentatively identified as terpenoids. When further GC-MS analysis was conducted, the presence of lupin-3-one, lupeol acetate, α-amyrin, and β-amyrin phytoconstituents were tentatively confirmed. These constituents are triterpenoids with established antiplasmodial activity which can be tentatively attributed to the bioactivity observed in P. capensis twigs., Conclusion: The study validates the ethnomedicinal use of P. capensis for malaria treatment. It demonstrated the potential of discovering novel antiplasmodial constituents that could serve as drug hits through dereplication approaches where known compounds with established antimalarial activity can be bypassed to focus on the unknown., Competing Interests: Declaration of competing interest Authors declare no conflict of interests., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Ripe figs, barks, and wood of Ficus vallis-choudae are used in traditional medicine against several conditions including nausea and malaria. However, its use is still to be scientifically documented and validated. Hence, the aim of the present work was to evaluate the antiplasmodial activity of the dichloromethane-methanol (DCM-MeOH (1:1)) crude extract, their hexane, dichloromethane, ethyl acetate, and methanoli fractions, as well as the isolated chemical constituents. The chemical study of the DCM-MeOH (1:1) crude extract of F. vallis-choudae figs led to the isolation of fifteen (15) known compounds identified based on their spectroscopic data [one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR), mass spectrometry] and by comparison of these data with those reported in the literature. Some of the isolated compounds were assessed in vitro for their antiplasmodial activity against Plasmodium falciparum chloroquine-sensitive 3D7 (Pf3D7) and multidrug-resistant Dd2 strains. The dichloromethane fraction exhibited very good antiplasmodial activity against both strains with IC 50 values of 13.86 μg/mL and 8.18 μg/mL, respectively. Among the tested compounds, wighteone (2) was the most active against P. falciparum 3D7 (IC 50  = 24.6 ± 1.5 μM) and Dd2 (IC 50  = 11.9 ± 2.4 μM) strains. The obtained results could justify the traditional uses of F. vallis-choudae against malaria. Wighteone appears to be the most active ingredient. However, further consideration of this compound as starting point for antimalarial drug discovery will depend upon its selectivity of action towards Plasmodium parasites. HIGHLIGHTS: • 15 (fifteen) compounds were isolated from the dichloromethane-methanol extract of Ficus vallis-choudae. • Their structures were determined on the basis of their spectroscopic data. • The dichloromethane fraction showed promising activities on the Pf3D7 and PfDd2 strains with IC 50 values of 13.86 and 8.18 µg/mL, respectively. • Wighteone was the most active compound against PfDd2 (IC 50  = 11.9 ± 2.4 μM)., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

For the purpose of improving the oral antimalarial activities of the fluorenemethanols (reported by us in previous articles) which were less effective by oral than by subcutaneous administration, 24 alpha-(alkylaminomethyl)-2, 7-dichloro-9-substituted benzylidene-4-fluorenemethanols (III) were synthesized. The results of preliminary screenings demonstrated that five compounds (No. 1-4, 8) exhibited significant antimalarial activities against Plasmodium berghei NK65 strain in mice by oral administration, at dose of 6.25 mg.kg-1.d-1 x 3 with suppressive rate of 100%. Further evaluation of these 5 compounds showed that 4 of them (No. 1-4) were superior to chloroquine in parallel tests, their ED50 and ED90 were 1.0, 1.6; 0.6, 0.9; 0.7, 1.5 and 0.8, 1.6 mg.kg-1.d-1 x 3 respectively, while the ED50 and ED90 of chloroquine were 1.9 and 2.9 mg.kg-1. d-1 x 3 respectively; one compound (No 8) was equal to chloroquine, its ED50 and ED90 were 1.5 and 3.2 mg.kg-1.d-1 x 3 respectively. Further assessment of these 4 compounds are in progress.

Pilot appraisals of the activities of 10 specially selected 2,6-substituted-4-pyridinemethanols against acute Plasmodium falciparum infections in owl monkeys identified three derivatives that were two to three times as active as chloroquine against infections with a 4-aminoquinoline-susceptible strain and, at the same doses, were equally effective against infections with a strain fully resistant to treatment with maximally tolerated doses of chloroquine, quinine, and pyrimethamine. Two of these derivatives, WR-172,435 and WR-180,409, deemed worthy of evaluation in human volunteers, were studied in greater depth in owl monkeys infected with either the multidrug-resistant Smith strain of P. falciparum or the pyrimethamine-resistant Palo Alto strain of P. vivax. These studies showed (i) that at the same total oral dose, 3-day and 7-day treatment schedules were equally effective and slightly superior to a single-dose schedule; (ii) that WR-172,435 was slightly more active than WR-180,409 in each treatment regimen; (iii) that intravenous delivery of WR-180,409 phosphate was feasible and effective; (iv) that both compounds effected control of parasitemia more rapidly than any standard or newly discovered antimalarial drug; and (v) that WR-172,435 and WR-180,409 had therapeutic indexes at least four to eight times those exhibited by chloroquine in infections with 4-aminoquinoline-susceptible strains, indexes retained by these pyridinemethanols against infections with various drug-resistant strains.

Two new investigational antimalarial drugs developed by the U.S. Army Malaria Research Program were tested in patients with multi-drug-resistant falciparum malaria from Vietnam. WR 33063, a phenanthrene methanol, cured 13 patients treated in the United States. All of these patients had suffered multiple recrudescences after treatment with standard antimalarial drugs. In addition, 23 of 25 patients with acute attacks of falciparum malaria treated in Vietnam were cured. The rate of clinical response was prompt. WR 30090, a quinoline methanol, similarly cured eight patients with multiple recrudescences in the United States and 23 of 26 patients in Vietnam. Adverse effects associated with the drugs were not seen. These drugs signify a major advance in the chemotherapy of drug-resistant falciparum malaria.

WR 33063, a phenanthrene methanol, was studied in human volunteers for tolerance and toxicity. In normal volunteers, it was possible to give 4.6 g in four divided doses without adverse effect for 10 days. At this dose level, there was neither evidence of photosensitivity nor adverse renal or cardiac effect. At a dose level of 1.6 g in four divided doses for 6 days, WR 33063 cured 18 of 23 nonimmune volunteers infected with the Smith strain of Plasmodium falciparum from Vietnam. In addition, infections due to the Marks and Braithwaite Vietnam strains were also treated because these strains represent a major therapeutic challenge to chloroquine; six of six and two of three volunteers, respectively, were cured. With the Malayan Camp strain, 1.6 g in four divided doses for 6 days cured all of five volunteers. The African Uganda I strain of chloroquine-responsive malaria was even more responsive to WR 33063; all of six men who received 1.6 g in four divided doses for 6 days were cured, and all of three men who received this same dosage for 3 days were cured. One subject infected with a Haitian strain of P. falciparum was treated and cured. Blood-induced infections with the Chesson strain of P. vivax also responded well to WR 33063 with four of five men cured. In all, 52 men received WR 33063 in tolerance trials, and 59 men with experimental malaria and one man with clinical malaria were treated with WR 33063.

WR 33063 (3-bromo-10-[alpha-hydroxy-beta-(n, n-diheptylamino)ethyl]-phenanthrene hydrochloride) and WR 30090 (6,8-dichloro-2,3,4-dichlorphenyl-di-n-butylaminoethyl-4- quinolinemethanol hydrochloride) were tested for suppressive prophylactic effect on induced malaria in nonimmune volunteers living in an area where malaria is not naturally transmitted. Doses of 800 mg of WR 33063 and 690 or 460 mg of WR 30090 were given at weekly intervals to men exposed on the day of the first dose to mosquitoes heavily infected with chloroquine- and pyrimethamine-resistant strains of Plasmodium falciparum. WR 33063 did not interfere with early development of infection, but WR 30090 given for 8 weeks provided suppressive cures in 20 of 26 men. P. vivax infections similarly induced broke through WR 30090 treatment in 4 of 15 men, and most of the remainder experienced malaria after completion of the prophylactic course. No side effects of treatment were observed.

WR 30090 at a dose of 230 mg every 8 hr for 6 days has proven to be a safe, well-tolerated compound with photosensitivity proving to be a minor consideration. WR 30090 was found to be an effective medication for the treatment of acute malaria caused by several strains of Plasmodium falciparum. At the dose of 230 mg every 8 hr for 6 days, all of six men infected with a chloroquine-susceptible strain (Uganda I) were cured, all of 13 subjects infected with moderately chloroquine-resistant strains (Malayan Camp, Malayan Taylor, and Philippine Per) were cured, and 19 of 23 subjects infected with strains highly resistant to chloroquine (Vietnam Smith and Vietnam Crocker) were cured. All of five subjects infected with the chloroquine-resistant Vietnam Marks strain were cured with only 3 days of therapy. Blood-induced P. vivax (Chesson strain) infection showed a mixed response. Six out of seven volunteers were cured when treated for 3 days with WR 30090. The one recrudescence responded to a repeated course of therapy for 3 days. However, recrudescence occurred in one volunteer treated for 6 days. Treatment with WR 30090 failed to cure sporozoite-induced P. vivax (Chesson strain) infection in any of four subjects. In all subjects treated, there was good suppression of parasitemia and relief of symptoms. The susceptibility of the strains of malaria to WR 30090 to some degree parallels their susceptibility to chloroquine.