In vivo antimalarial effect of 1-hydroxy-5,6,7-trimethoxyxanthone isolated from Mammea siamensis T. Anders. flowers: pharmacokinetic and acute toxicity studies.

BACKGROUND: The potent antiplasmodial activity of 1-hydroxy-5,6,7-trimethoxyxanthone (HTX), isolated from Mammea siamensis T. Anders. flowers, has previously been demonstrated in vitro. However, its in vivo activity has not been reported. Therefore, this study aimed to investigate the antimalarial activity and acute toxicity of HTX in a mouse model and to evaluate the pharmacokinetic profile of HTX following a single intraperitoneal administration. METHODS: The in vivo antimalarial activity of HTX was evaluated using a 4-day suppressive test. Mice were intraperitoneally injected with Plasmodium berghei ANKA strain and given HTX daily for 4 days. To detect acute toxicity, mice received a single dose of HTX and were observed for 14 days. Additionally, the biochemical parameters of the liver and kidney functions as well as the histopathology of liver and kidney tissues were examined. HTX pharmacokinetics after intraperitoneal administration was also investigated in a mouse model. Liquid chromatography triple quadrupole mass spectrometry was used to quantify plasma HTX and calculate pharmacokinetic parameters with the PKSolver software. RESULTS: HTX at 10 mg/kg body weight significantly suppressed parasitemia in malaria-infected mice by 74.26%. Mice treated with 3 mg/kg HTX showed 46.88% suppression, whereas mice treated with 1 mg/kg displayed 34.56% suppression. Additionally, no symptoms of acute toxicity were observed in the HTX-treated groups. There were no significant alterations in the biochemical parameters of the liver and kidney functions and no histological changes in liver or kidney tissues. Following intraperitoneal HTX administration, the pharmacokinetic profile exhibited a maximum concentration (Cmax) of 94.02 ng/mL, time to attain Cmax (Tmax) of 0.5 h, mean resident time of 14.80 h, and elimination half-life of 13.88 h. CONCLUSIONS: HTX has in vivo antimalarial properties against P. berghei infection. Acute toxicity studies of HTX did not show behavioral changes or mortality. The median lethal dose was greater than 50 mg/kg body weight. Pharmacokinetic studies showed that HTX has a long elimination half-life; hence, shortening the duration of malaria treatment may be required to minimize toxicity.

Assessment of antimalarial activity of crude extract of Chan-Ta-Lee-La and Pra-Sa-Chan-Dang formulations and their plant ingredients for new drug candidates of malaria treatment: In vitro and in vivo experiments.

The emergence and spread of antimalarial drug resistance have become a significant problem worldwide. The search for natural products to develop novel antimalarial drugs is challenging. Therefore, this study aimed to assess the antimalarial and toxicological effects of Chan-Ta-Lee-La (CTLL) and Pra-Sa-Chan-Dang (PSCD) formulations and their plant ingredients. The crude extracts of CTLL and PSCD formulations and their plant ingredients were evaluated for in vitro antimalarial activity using Plasmodium lactate dehydrogenase enzyme and toxicity to Vero and HepG2 cells using the tetrazolium salt method. An extract from the CTLL and PSCD formulations exhibiting the highest selectivity index value was selected for further investigation using Peter's 4-day suppressive test, curative test, prophylactic test, and acute oral toxicity in mice. The phytochemical constituents were characterized using gas chromatography-mass spectrometry (GC-MS). Results showed that ethanolic extracts of CTLL and PSCD formulations possessed high antimalarial activity (half maximal inhibitory concentration = 4.88, and 4.19 g/mL, respectively) with low cytotoxicity. Ethanolic extracts of the CTLL and PSCD formulations demonstrated a significant dose-dependent decrease in parasitemia in mice. The ethanolic CTLL extract showed the greatest suppressive effect after 4 days of suppressive (89.80%) and curative (35.94%) testing at a dose of 600 mg/kg. Moreover, ethanolic PSCD extract showed the highest suppressive effect in the prophylactic test (65.82%) at a dose of 600 mg/kg. There was no acute toxicity in mice treated with ethanolic CTLL and PSCD extracts at 2,000 mg/kg bodyweight. GC-MS analysis revealed that the most abundant compounds in the ethanolic CTLL extract were linderol, isoborneol, eudesmol, linoleic acid, and oleic acid, whereas ethyl 4-methoxycinnamate was the most commonly found compound in the ethanolic PSCD extract, followed by 3-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-4H-chromen-4-one, flamenol, oleic acid amide, linoleic acid, and oleic acid. In conclusions, ethanolic CTLL and PSCD extracts exhibited high antimalarial efficacy in vitro. The ethanolic CTLL extract at a dose of 600 mg/kg exhibited the highest antimalarial activity in the 4-day suppressive and curative tests, whereas the ethanolic PSCD extract at a dose of 600 mg/kg showed the highest antimalarial activity in the prophylactic test.

Phytochemical Analysis, Antimalarial Properties, and Acute Toxicity of Aqueous Extracts of Trisamo and Jatu-Phala-Tiga Recipes.

Drug resistance remains a significant problem that threatens antimalarial drug treatment. Hence, the challenge is to find new effective antimalarial drugs. Based on our previous study, aqueous extracts of trisamo (TSM) and jatu-phala-tiga (JPT) had good in vitro antimalarial activities, and these recipes contain multiple beneficial pharmacological effects that could be useful for malaria therapy. Therefore, this study aimed to investigate the antimalarial activity and toxicity of the aqueous extracts of TSM and JPT in mouse models. The aqueous extractions were carried out using the decoction method. Compound identification was conducted using LC-QTOF-MS analysis. The antimalarial activities of TSM and JPT at doses 200, 400, and 600 mg/kg were evaluated against Plasmodium berghei ANKA infection using a four-day suppressive test. The toxic effects of oral administration of the extracts at 2 g/kg dose were determined using an acute toxicity test. The chemical constituents of TSM contained 83 compounds, whereas JPT contained 84 compounds. All doses of the extracts exhibited a significant suppression (p < 0.05) of the parasite compared to the negative control in a four-day test. The maximum activities were observed at 600 mg/kg dose with 67.02% suppression for TSM and 79.34% for JPT, followed by 400 mg/kg dose (57.63% for TSM and 64.79% for JPT) and then 200 mg/kg dose (52.35% for TSM and 54.46% for JPT). In addition, there were no significant differences (p < 0.05) in the RBC, MCV, and MCH levels of mice receiving JPT extract compared to the uninfected control. The WBC level of mice receiving 400 and 600 mg/kg of TSM, and 200 and 400 mg/kg of JPT, was significantly (p < 0.05) lower than the infected control, and the extracts did not significantly prevent the loss of platelets. For the acute toxicity test, there were no signs of toxicity or deaths in mice, and there were no differences in the histology, weight, or enzyme biochemistry of the liver and kidney between the extract and vehicle groups. However, the platelet count in the extract-treated mice was significantly higher than that in the control group. In conclusion, this study suggests that aqueous extracts of TSM and JPT have potent antimalarial activities and could be promising as new candidates for antimalarial drug development.

Efficacy of artesunate combined with Atractylodes lancea or Prabchompoothaweep remedy extracts as adjunctive therapy for the treatment of cerebral malaria.

BACKGROUND: Cerebral malaria is one of the most serious complications of Plasmodium infection and causes behavioral changes. However, current antimalarial drugs have shown poor outcomes. Therefore, new antimalarials with neuroprotective effects are urgently needed. This study aimed to evaluate the effects of selected extracts as monotherapy or adjunctive therapy with artesunate on antimalarial, anti-inflammatory, antioxidant, and neuroprotective properties in experimental cerebral malaria (ECM). METHODS: ECM was induced in male C57BL/6 mice by infection with Plasmodium berghei ANKA (PbA). Ethanolic extracts of Atractylodes lancea (a dose of 400 mg/kg) and Prabchompoothaweep remedy (a dose of 600 mg/kg) were evaluated as monotherapy and adjunctive therapy combined with artesunate at the onset of signs of cerebral malaria and continued for 7 consecutive days. Parasitemia, clinical scores, and body weight were recorded throughout the study. At day 13 post-infection, mouse brains were dissected and processed for the study of the inflammatory response, oxidative stress, blood-brain barrier (BBB) integrity, histopathological changes, and neurocognitive impairments. RESULTS: Ethanolic extracts of A. lancea and Prabchompoothaweep remedy alone improved cerebral malaria outcome in ECM, whereas artesunate combined with extracts of A. lancea or Prabchompoothaweep remedy significantly improved the outcome of artesunate and crude extracts alone. Using real-time PCR, PbA-infected mice that had received the combination treatment showed significantly reduced gene expression of inflammatory cytokines (TNF-α, IL-1ß, IL-6, and IL-10), chemokines (CXCL4 and CXCL10), and adhesion molecules (ICAM-1, VCAM1, and CD36). The PbA-infected mice that received the combination treatment showed a significantly decreased malondialdehyde level compared to the untreated group. Similarly, the Evans blue dye assay revealed significantly less dye extravasation in the brains of infected mice administered the combination treatment, indicating improved BBB integrity. Combination treatment improved survival and reduced pathology in the PbA-infected group. Additionally, combination treatment resulted in a significantly reduced level of cognitive impairment, which was analyzed using a novel object recognition test. CONCLUSIONS: This study demonstrated that artesunate combined with A. lancea or Prabchompoothaweep remedy extracts as adjunctive therapy reduced mortality, neuroinflammation, oxidative stress, BBB integrity protection, and neurocognitive impairment in the ECM.

Preclinical evaluation of antimalarial activity of CPF-1 formulation as an alternative choice for the treatment of malaria.

BACKGROUND: Kheaw Hom remedy is a traditional Thai medicine used to treat fever. Some plants used in the Kheaw Hom remedy show promising in vitro antimalarial activity. This study prepared novel formulations of plants from the Kheaw Hom remedy and evaluated their antimalarial and toxicological activities. METHODS: Seven new formulations were prepared by combining at least three herbs of six selected plants from the Kheaw Hom remedy, namely Mammea siamensis Kosterm., Mesua ferrea L., Dracaena loureiroi Gagnep., Pogostemon cablin (Blanco) Benth., Kaempferia galanga L, and Eupatorium stoechadosmum Hance. In vitro antimalarial activities of each formulation's aqueous and ethanolic extracts were evaluated using the parasite lactate dehydrogenase (pLDH) assay. Cytotoxicity in Vero and HepG2 cells was assessed using the MTT assay. An extract with good antimalarial potency and selectivity index (SI) was selected for in vivo antimalarial activity using Peter's 4-day suppressive test and acute oral toxicity test in mice. In addition, bioactive compounds were identified using Gas chromatography-mass spectrometry (GC-MS) analysis. RESULTS: Among the seven new formulations, ethanolic extracts of CPF-1 (Formulation 1) showed the highest activity with an IC50 value of 1.32 ± 0.66 µg/ml, followed by ethanolic extracts of Formulation 4 and Formulation 6 with an IC50 value of 1.52 ± 0.28 µg/ml and 2.48 ± 0.34 µg/ml, respectively. The highest SI values were obtained for the ethanolic extract of CPF-1 that was selected to confirm its in vivo antimalarial activity and toxicity. The results demonstrated a significant dose-dependent reduction in parasitemia. Maximum suppressive effect of the extract (72.01%) was observed at the highest dose administered (600 mg/kg). No significant toxicity was observed after the administration of 2000 mg/kg. Using GC-MS analysis, the most abundant compound in the ethanolic extract of CPF-1 was ethyl p-methoxycinnamate (14.32%), followed by 2-propenoic acid, 3-phenyl-, ethyl ester, (E)- (2.50%), and pentadecane (1.85%). CONCLUSION: The ethanolic extract of CPF-1 showed promising in vitro and in vivo antimalarial efficacy, with no toxic effects at a dose of 2000 mg/kg, suggesting that the ethanolic extract of CPF-1 may serves as a new herbal formulation for the treatment of malaria. Additional research is required for safety and clinical pharmacology studies.

Antimalarial efficacy and toxicological assessment of medicinal plant ingredients of Prabchompoothaweep remedy as a candidate for antimalarial drug development.

BACKGROUND: Drug resistance exists in almost all antimalarial drugs currently in use, leading to an urgent need to identify new antimalarial drugs. Medicinal plant use is an alternative approach to antimalarial chemotherapy. This study aimed to explore potent medicinal plants from Prabchompoothaweep remedy for antimalarial drug development. METHODS: Forty-eight crude extracts from Prabchompoothaweep remedy and its 23 plants ingredients were investigated in vitro for antimalarial properties using Plasmodium lactate dehydrogenase (pLDH) enzyme against Plasmodium falciparum K1 strain and toxicity effects were evaluated in Vero cells. The plant with promising antimalarial activity was further investigated using gas chromatography-mass spectrometry (GC-MS) to identify phytochemicals. Antimalarial activity in mice was evaluated using a four-day suppressive test against Plasmodium berghei ANKA at dose of 200, 400, and 600 mg/kg body weight, and acute toxicity was analyzed. RESULTS: Of the 48 crude extracts, 13 (27.08%) showed high antimalarial activity against the K1 strain of P. falciparum (IC50 <  10 µg/ml) and 9 extracts (18.75%) were moderately active (IC50 = 11-50 µg/ml). Additionally, the ethanolic extract of Prabchompoothaweep remedy showed moderate antimalarial activity against the K1 strain of P. falciparum (IC50 = 14.13 µg/ml). Based on in vitro antimalarial and toxicity results, antimalarial activity of the aqueous fruit extract of Terminalia arjuna (IC50 = 4.05 µg/ml and CC50 = 219.6 µg/ml) was further studied in mice. GC-MS analysis of T. arjuna extract identified 22 compounds. The most abundant compounds were pyrogallol, gallic acid, shikimic acid, oleamide, 5-hydroxymethylfurfural, 1,1-diethoxy-ethane, quinic acid, and furfural. Analysis of the four-day suppressive test indicated that T. arjuna extract at dose of 200, 400, and 600 mg/kg body weight significantly suppressed the Plasmodium parasites by 28.33, 45.77, and 67.95%, respectively. In the acute toxicity study, T. arjuna extract was non-toxic at 2000 mg/kg body weight. CONCLUSIONS: The aqueous fruit extract of T. arjuna exerts antimalarial activity against Plasmodium parasites found in humans (P. falciparum K1) and mice (P. berghei ANKA). Acute toxicity studies showed that T. arjuna extract did not show any lethality or adverse effects up to a dose of 2000 mg/kg.

Phytochemical, Antimalarial, and Acute Oral Toxicity Properties of Selected Crude Extracts of Prabchompoothaweep Remedy in Plasmodium berghei-Infected Mice.

Malaria remains a life-threatening health problem and encounters with the increasing of antimalarial drug resistance. Medicinal plants play a critical role in synthesizing novel and potent antimalarial agents. This study aimed to investigate the phytochemical constituents, antiplasmodial activity, and evaluate the toxicity of crude ethanolic extracts of Myristica fragrans, Atractylodes lancea, and Prabchompoothaweep remedy in a mouse model. The phytochemical constituents were characterized by liquid chromatography-mass spectrometry (LC-MS). Antimalarial efficacy against Plasmodium berghei was assessed using 4-day suppressive tests at doses of 200, 400, and 600 mg/kg body weight. Acute toxicity was assessed at a dose of 2000 mg/kg body weight of crude extracts. The 4-day suppression test showed that all crude extracts significantly suppressed parasitemia (p < 0.05) compared to the control group. Higher parasitemia suppression was observed both in Prabchompoothaweep remedy at a dose of 600 mg/kg (60.1%), and A. lancea at a dose of 400 mg/kg (60.1%). The acute oral toxicity test indicated that the LD50 values of all extracts were greater than 2000 mg/kg and that these extracts were not toxic in the mouse model. LC-MS analysis revealed several compounds in M. fragrans, A. lancea, and Prabchompoothaweep remedy. For quantitative analysis, 1,2,6,8-tetrahydroxy-3-methylanthraquinone 2-O-b-D-glucoside, chlorogenic acid, and 3-O-(beta-D-glucopyranosyl-(1->6)-beta-D-glucopyranosyl) ethyl 3-hydroxyoctanoate were found in A. lancea, while (7'x,8'x)-4,7'-epoxy-3,8'-bilign-7-ene-3,5'-dimethoxy-4',9,9'-triol, edulisin III, and tetra-hydrosappanone A trimethyl ether are found in M. fragrans. 6'-O-Formylmarmin was present in the Prabchompoothaweep remedy, followed by pterostilbene glycinate and amlaic acid. This study showed that the ethanolic extracts of A. lancea and Prabchompoothaweep remedy possess antimalarial activity against Plasmodium berghei. None of the extracts had toxic effects on liver and kidney function. Therefore, the ethanolic extract of A. lancea rhizome and Prabchompoothaweep remedy could be used as an alternative source of new antimalarial agents. Further studies are needed to determine the active compounds in both extracts.

Antiplasmodial Properties of Aqueous and Ethanolic Extracts of Ten Herbal Traditional Recipes Used in Thailand against Plasmodium falciparum.

This study evaluated the in vitro and in vivo antiplasmodial efficacy and toxicity of aqueous and ethanolic extracts from traditional recipes used in Thailand. The aqueous and ethanolic extracts of ten traditional recipes were tested for in vitro antiplasmodial activity (parasite lactate dehydrogenase assay), cytotoxicity (MTT assay), and hemolysis). Oxidant levels were measured using cell-permeable probe 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate fluorescent dye-based assays. The best candidate was chosen for testing in mouse models using 4-day suppressive and acute toxicity assays. An in vitro study showed that ethanolic extracts and three aqueous extracts exhibited antiplasmodial activity, with an IC50 in the range of 2.8-15.5 µg/mL. All extracts showed high CC50 values, except for ethanolic extracts from Benjakul, Benjalotiga, and Trikatuk in HepG2 and Benjalotiga and aqueous extract from Chan-tang-ha in a Vero cell. Based on the results of the in vitro antiplasmodial activity, an aqueous extract of Triphala was chosen for testing in mouse models. The aqueous extract of Triphala exhibited good antiplasmodial activity, was safe at an oral dose of 2 g/kg, and is a potential candidate as a new source for the development of antimalarial drugs.

Exploring Potential Antimalarial Candidate from Medicinal Plants of Kheaw Hom Remedy.

The Kheaw Hom remedy is a traditional Thai medicine widely used to treat fevers. Some plant ingredients in this remedy have been investigated for their antimicrobial, antiviral, anti-inflammatory, and antioxidant activities. However, there have been no reports on the antimalarial activities of the medicinal plants in this remedy. Therefore, this study focuses on identifying potential antimalarial drug candidates from the medicinal plant ingredients of the Kheaw Hom remedy. Eighteen plants from the Kheaw Hom remedy were extracted using distilled water and ethanol. All extracts were investigated for their in vitro antimalarial activity and cytotoxicity. An extract that exhibited good in vitro antimalarial activity and low toxicity was selected for further investigation by using Peter's 4-day suppressive test and an acute oral toxicity evaluation in mice. Based on the in vitro antimalarial activity and cytotoxicity studies, the ethanolic extract of Globba malaccensis rhizomes showed promising antimalarial activity against the Plasmodium falciparum K1 strain (IC50 = 1.50 µg/mL) with less toxicity to Vero cells (CC50 of >80 µg/mL). This extract exhibited a significant dose-dependent reduction in parasitemia in P. berghei-infected mice. The maximum suppressive effect of this extract (60.53%) was observed at the highest dose administered (600 mg/kg). In a single-dose acute toxicity test, the animals treated at 2000 mg/kg died within 48 h after extract administration. In conclusion, our study indicates that the ethanolic extract of G. malaccensis rhizomes exhibited in vitro and in vivo antimalarial activities, which could serve as a promising starting point for antimalarial drug.

Antimalarial potential of compounds isolated from Mammea siamensis T. Anders. flowers: in vitro and molecular docking studies.

BACKGROUND: The emergence of antimalarial drug resistance encourages the search for new antimalarial agents. Mammea siamensis belongs to the Calophyllaceae family, which is a medicinal plant that is used in traditional Thai preparations. The hexane and dichloromethane extracts of this plant were found to have potent antimalarial activity. Therefore, this study aimed to isolate active compounds from M. siamensis flowers and evaluate their antimalarial potential and their interactions with Plasmodium falciparum lactate dehydrogenase (PfLDH). METHODS: The compounds from M. siamensis flowers were isolated by chromatographic techniques and evaluated for their antimalarial activity against chloroquine (CQ)-resistant P. falciparum (K1) strains using a parasite lactate dehydrogenase (pLDH) assay. Interactions between the isolated compounds and the PfLDH enzyme were investigated using a molecular docking method. RESULTS: The isolation produced the following thirteen compounds: two terpenoids, lupeol (1) and a mixture of ß-sitosterol and stigmasterol (5); two mammea coumarins, mammea A/AA cyclo D (6) and mammea A/AA cyclo F (7); and nine xanthones, 4,5-dihydroxy-3-methoxyxanthone (2), 4-hydroxyxanthone (3), 1,7-dihydroxyxanthone (4), 1,6-dihydroxyxanthone (8), 1-hydroxy-5,6,7-trimethoxyxanthone (9), 3,4,5-trihydroxyxanthone (10), 5-hydroxy-1-methoxyxanthone (11), 2-hydroxyxanthone (12), and 1,5-dihydroxy-6-methoxyxanthone (13). Compound 9 exhibited the most potent antimalarial activity with an IC50 value of 9.57 µM, followed by 10, 1, 2 and 13 with IC50 values of 15.48, 18.78, 20.96 and 22.27 µM, respectively. The molecular docking results indicated that 9, which exhibited the most potent activity, also had the best binding affinity to the PfLDH enzyme in terms of its low binding energy (-7.35 kcal/mol) and formed interactions with ARG109, ASN140, and ARG171. CONCLUSION: These findings revealed that isolated compounds from M. siamensis flowers exhibited antimalarial activity. The result suggests that 1-hydroxy-5,6,7-trimethoxyxanthone is a possible lead structure as a potent inhibitor of the PfLDH enzyme.

In vivo assessment of the antimalarial activity and acute oral toxicity of an ethanolic seed extract of Spondias pinnata (L.f.) Kurz.

BACKGROUND: In response to the persistent problem of malaria resistance, medicinal herbal plants can be used as a source of potential novel antimalarial agents. Therefore, the aim of this study was to evaluate the in vivo antimalarial activity and toxicity of an ethanolic seed extract of Spondias pinnata (L.f.) Kurz (S. pinnata). METHODS: Qualitative phytochemical screening of the extract was performed using standard procedures, and the constituents were determined by gas chromatography-mass spectrometry (GC-MS). The in vivo antimalarial activity was assessed against the Plasmodium berghei ANKA strain in mice based on 4-day suppressive, curative and prophylactic tests. In addition, the acute toxicity of the extract was evaluated after oral administration of a single dose of 2,000 mg/kg body weight. RESULTS: Phytochemical screening tests on the ethanolic S. pinnata seed extract revealed the presence of terpenoids, tannins, and coumarins. GC-MS analysis of the extract led to the identification of twenty-nine phytochemical compounds, including oleic acid amide, ß-sitosterol, linoleic acid, oleic acid, protocatechuic acid, syringic acid and gallic acid. The results of the 4-day suppressive test revealed that mice treated with 250, 500, 600 and 800 mg/kg doses of the ethanolic S. pinnata seed extract showed significant parasitemia suppression in a dose-dependent manner, with 22.94, 49.01, 60.67 and 66.82% suppression, respectively, compared to that of the negative control group. All the doses of the ethanolic seed extract significantly suppressed parasitemia (P < 0.05) during the curative activity test and prolonged the mean survival time compared to those of the negative control group. However, the ethanolic seed extract displayed lower curative and prophylactic activities than the standard drug artesunate. In addition, the ethanolic seed extract showed no signs of toxicity in mice at a dose of 2,000 mg/kg body weight. CONCLUSION: The S. pinnata seed extract contains various phytochemical compounds with important medicinal properties. The extract showed a significant suppression of parasitemia in a dose-dependent manner, prolonged the mean survival time and exhibited significant curative and prophylactic activities. The overall results of this study demonstrated that the S. pinnata seed extract possessed promising in vivo antimalarial activity against P. berghei ANKA, with no toxicity. The findings from the present study provide scientific evidence supporting the use of S. pinnata seeds in the development of new drugs for malaria treatment. Additional studies are needed to isolate and identify the active compounds as well as to understand the mechanism of inhibition.

Antiplasmodial activity and cytotoxicity of plant extracts from the Asteraceae and Rubiaceae families.

The increasing resistance of parasites to antimalarial drugs and the limited number of effective drugs are the greatest challenges in the treatment of malaria. It is necessary to search for an alternative medicine for use as a new, more effective antimalarial drug. Therefore, this study aimed to evaluate the in vitro antimalarial activity and cytotoxicity of extracts from plants belonging to the Asteraceae and Rubiaceae families. The phytoconstituents of one hundred ten ethanolic and aqueous extracts from different parts of twenty-three plant species were analyzed. Evaluation of their antimalarial activities against the chloroquine (CQ)-resistant Plasmodium falciparum (K1) strain was carried out using the lactate dehydrogenase (pLDH) assay, and their cytotoxicity in Vero cells was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric method. A total of 40.91% of the extracts were active antimalarial agents. Three extracts (2.73%) exhibited high antiplasmodial activity (IC50 < 10 µg/ml), twenty-four extracts (21.82%) were moderately active with IC50 values ranging from 10-50 µg/ml, and eighteen extracts (16.36%) were mildly active with IC50 values ranging from 50-100 µg/ml. The ethanolic leaf extract of Mussaenda erythrophylla (Dona Trining; Rubiaceae) exhibited the highest activity against P. falciparum, with an IC50 value of 3.73 µg/ml and a selectivity index (SI) of 30.74, followed by the ethanolic leaf extract of Mussaenda philippica Dona Luz x M. flava (Dona Marmalade; Rubiaceae) and the ethanolic leaf extract of Blumea balsamifera (Camphor Tree; Asteraceae), with IC50 values of 5.94 and 9.66 µg/ml and SI values of 25.36 and >20.70, respectively. GC-MS analysis of these three plant species revealed the presence of various compounds, such as squalene, oleic acid amide, ß-sitosterol, quinic acid, phytol, oleamide, α-amyrin, sakuranin, quercetin and pillion. In conclusion, the ethanolic leaf extract of M. erythrophylla, the leaf extract of M. philippica Dona Luz x M. flava and the leaf extract of B. balsamifera had strong antimalarial properties with minimal toxicity, indicating that compounds from these plant species have the potential to be developed into new antiplasmodial agents.

Evaluation of the antimalarial activity and toxicity of Mahanil-Tang-Thong formulation and its plant ingredients.

BACKGROUND: Novel potent antimalarial agents are urgently needed to overcome the problem of drug-resistant malaria. Herbal treatments are of interest because plants are the source of many pharmaceutical compounds. The Mahanil-Tang-Thong formulation is a Thai herbal formulation in the national list of essential medicines and is used for the treatment of fever. Therefore, this study aimed to evaluate the antimalarial activity of medicinal plants in the Mahanil-Tang-Thong formulation. METHODS: Nine medicinal plant ingredients of the Mahanil-Tang-Thong formulation were used in this study. Aqueous and ethanolic extracts of all the plants were analyzed for their phytochemical constituents. All the extracts were used to investigate the in vitro antimalarial activity against Plasmodium falciparum K1 (chloroquine-resistant strain) by using the lactate dehydrogenase (pLDH) method and cytotoxicity in Vero cells by using the 3-(4,5-dimethylthiazol2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Additionally, an extract with potent in vitro antimalarial activity and no toxicity was selected to determine the in vivo antimalarial activity with Peters' 4-day suppressive test against the Plasmodium berghei ANKA strain. Acute toxicity was evaluated in mice for 14 days after the administration of a single oral dose of 2000 mg/kg. RESULTS: This study revealed that ethanolic extracts of Sapindus rarak DC., Tectona grandis L.f., Myristica fragrans Houtt. and Dracaena loureiri Gagnep. exhibited potent antimalarial activity, with half-maximal inhibitory concentration (IC50) values of 2.46, 3.21, 8.87 and 10.47 µg/ml, respectively, while the ethanolic of the formulation exhibited moderate activity with an IC50 value of 37.63 µg/ml and its aqueous extract had no activity (IC50 = 100.49 µg/ml). According to the in vitro study, the ethanolic wood extract of M. fragrans was selected for further investigation in an in vivo mouse model. M. fragrans extract at doses of 200, 400, and 600 mg/kg body weight produced a dose-dependent reduction in parasitemia by 8.59, 31.00, and 52.58%, respectively. No toxic effects were observed at a single oral dose of 2000 mg/kg body weight. CONCLUSION: This study demonstrates that M. fragrans is a potential candidate for the development of antimalarial agents.

In Vivo Antimalarial Activity and Toxicity Study of Extracts of Tagetes erecta L. and Synedrella nodiflora (L.) Gaertn. from the Asteraceae Family.

OBJECTIVE: To investigate the antimalarial effects and toxicity of the extracts of the flowers of Tagetes erecta L. and the leaves of Synedrella nodiflora (L.) Gaertn. in a mouse model. METHODS: To determine the in vivo antimalarial activity of the extracts, mice were intraperitoneally injected with the Plasmodium berghei ANKA strain and then administered T. erecta or S. nodiflora extract daily for 4 days. Parasitemia was observed by light microscopy. For the detection of acute toxicity, the mice received a single dose of T. erecta or S. nodiflora extract and were observed for 14 days. Biochemical parameters of liver and kidney function and the histopathology of liver and kidney tissues of the acute toxicity group were then examined. RESULTS: T. erecta and S. nodiflora crude extracts at a dose of 600 mg/kg body weight significantly suppressed parasitemia in malaria-infected mice by 65.65% and 62.65%, respectively. Mice treated with 400 mg/kg T. erecta and S. nodiflora crude extracts showed 50.82% and 57.67% suppression, and mice treated with 200 mg/kg displayed 26.33% and 38.57% suppression, respectively. Additionally, no symptoms of acute toxicity were observed in the T. erecta- and S. nodiflora-treated groups. Moreover, no significant alterations in the biochemical parameters of liver and kidney function and no histological changes in the liver or kidney tissues were observed. CONCLUSIONS: This study revealed that both T. erecta and S. nodiflora extracts have antimalarial properties in vivo with less toxic effects. Further studies are needed to elucidate the mechanisms of the active compounds from both plants.

Antioxidant and antimalarial properties of Sophora exigua Craib. root extract in Plasmodium berghei-infected mice.

BACKGROUND: Sophora exigua Craib. is commonly used in Thailand to reduce fever and increase postpartum breast milk production in women who have hypogalactia. However, there has been no report on the antioxidant and antimalarial properties of this plant. This study aimed to investigate the antioxidant and antimalarial activities of S. exigua root extract and to evaluate its acute toxicity in mice to confirm its safety. METHODS: The in vitro antioxidant activities were determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide radical, and hydroxyl radical scavenging assays. The in vivo antioxidant activities were determined by detecting the malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in the livers of malaria-infected mice. The in vivo antimalarial activity was determined by Peters' 4-day suppressive test in mice infected with Plasmodium berghei ANKA and orally administered S. exigua root aqueous and ethanolic extracts at different doses (200, 400, and 600 mg/kg body weight). In addition, the acute oral toxicity of the plant extracts was assessed in mice at a dose of 2000 mg/kg body weight. RESULTS: The ethanolic extract of S. exigua root exhibited inhibition of DPPH radicals, superoxide anions, and hydroxyl radicals, with half maximal inhibitory concentration (IC50) values of 24.63 ± 1.78, 129.78 ± 0.65, and 30.58 ± 1.19 µg/ml, respectively. Similarly, research on the in vivo antioxidant activity indicated that the ethanolic extract of S. exigua root exerted a stronger effect than the aqueous extract. The aqueous extract at doses of 200, 400, and 600 mg/kg had stronger antimalarial activity than the ethanolic extract. The aqueous extract at 600 mg/kg exhibited 60.46% suppression of parasitemia. Increased levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) and blood urea nitrogen (BUN) were detected in the mice treated with 2000 mg/kg ethanolic extract, which was related to the results of histopathological analysis of liver tissue, showing ballooning degeneration of hepatocytes, diffuse hepatic hemorrhage, and infiltration of inflammatory cells. CONCLUSIONS: This study demonstrated that the ethanolic S. exigua root extract possessed antioxidant properties, and the aqueous extract also had antimalarial activity. Therefore, this plant is an alternative source of new antioxidant and antimalarial agents.

In Vitro and In Vivo Antimalarial Activities and Toxicological Assessment of Pogostemon Cablin (Blanco) Benth.

The aim of this study was to investigate the antimalarial activities and toxicity of Pogostemon cablin extracts. In vitro activities against the chloroquine-resistant Plasmodium falciparum K1 strain were assessed by using the Plasmodium lactate dehydrogenase enzyme (pLDH) assay, while in vivo activity against the Plasmodium berghei ANKA strain in mice was investigated using a 4-day suppressive test. The in vitro and in vivo toxicity were determined in Vero cells and mice, respectively. The ethanolic extract possessed antimalarial activity with an IC50 of 24.49 ± 0.01 µg/ml, whereas the aqueous extract showed an IC50 of 549.30 ± 0.07 µg/ml. Cytotoxic analyses of the ethanolic and aqueous extracts revealed a nontoxic effect on Vero cells at a concentration of 80 µg/ml. Based on a preliminary study of in vitro antimalarial activity, the ethanolic extract was chosen as a potential agent for further in vivo antimalarial activity analysis in mice. The ethanolic extract, which showed no toxic effect on mice at a dose of 2000 mg/kg body weight, significantly suppressed parasitemia in mice by 38.41%, 45.12% and 89.00% at doses of 200, 400 and 600 mg/kg body weight, respectively. In conclusion, this study shows that the ethanolic P. cablin extract possesses in vitro and in vivo antimalarial activity without toxic effects.

Antimalarial Activity and Toxicological Assessment of Betula alnoides Extract against Plasmodium berghei Infections in Mice.

The resistance of malaria parasites to the current antimalarial drugs has led to the search for novel effective drugs. Betula alnoides has been traditionally used for the treatment of malaria, but the scientific evidence to substantiate this claim is still lacking. Therefore, the present study aimed at evaluating the antimalarial activity and toxicity of an aqueous stem extract of B. alnoides in a mouse model. The in vivo antimalarial activity of an aqueous stem extract of B. alnoides was determined by a 4-day suppressive test in mice infected with chloroquine-sensitive Plasmodium berghei ANKA. The B. alnoides extract was administered orally at different doses of 200, 400, and 600 mg/kg body weight. The levels of parasitaemia, survival time, body weight change, and food and water consumption of the mice were determined. The acute toxicity of the extract was assessed in the mice for 14 days after the administration of a single oral dose of 5000 mg/kg. An aqueous stem extract of B. alnoides exhibited a significant dose-dependent reduction of parasitaemia in P. berghei-infected mice at all dose levels compared to the reduction in the negative control. Extract doses of 200, 400, and 600 mg/kg body weight suppressed the levels of parasitaemia by 46.90, 58.39, and 71.26%, respectively. The extract also significantly prolonged the survival times of the P. berghei-infected mice compared to the survival times of the negative control mice. In addition, at all dose levels, the extract prevented body weight loss in P. berghei-infected mice. For the acute toxicity, there were no significant alterations in the biochemical parameters and in the histopathology. In conclusion, the aqueous stem extract of B. alnoides possesses antimalarial properties. A single oral dose of 5000 mg/kg body weight had no significant toxic effects on the function and structure of the kidneys and liver. These results support its use in traditional medicine for the treatment of malaria.