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

Antimalarial Drug Discovery from Natural and Synthetic Sources

Malaria remains a significant global health threat despite extensive efforts aimed at its eradication. Numerous challenges persist in eliminating the disease, chief among them being the parasite's ability to mutate, resulting in drug resistance. The discovery of antimalarial drugs has relied on both phenotypic and target-based approaches. While phenotypic screening has identified promising candidates, target-based methods offer a more precise approach by leveraging chemically validated targets and computational tools. Analysis of Plasmodium spp . protein structures reveal druggable targets, offering opportunities for in silico screening. Combining compounds from natural and synthetic sources in a target-based approach accelerates the discovery of new antimalarial agents. This review explores previous breakthroughs in antimalarial drug discovery from natural products and synthetic origins, emphasizing their specific target proteins within Plasmodium species.

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.

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.

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.

Study of Traditional Uses, Extraction Procedures, Phytochemical Constituents, and Pharmacological Properties of Tiliacora triandra

Tiliacora triandra (Colebr.) Diels (Menispermaceae family) is a Southeast Asian angiosperm herb. Traditional medicine in these areas often includes the use of plant parts. Plant extracts are highly effective against various infections including bacterial, fungal, viral, and parasitic. The leaves and root extracts are used to treat gastrointestinal diseases, hypertension, diabetes, skin diseases, and malaria as an antipyretic, detoxification agent, anti-inflammatory, anticancer, and immunomodulator. Bioactive compounds contained in T. triandra include phenolic compounds, alkaloids, flavonoids, terpenoids, fatty acids, essential amino acids, peptides, carbohydrates, vitamins, and nucleic acid precursors. Despite the plant species’ abundance of bioactive compounds, there is very little in vivo and clinical proof of its pharmacological significance. The present review focuses on the phytochemical configurations, extraction methods for major bioactive compounds, and pharmacology of T. triandra, in light of its potent medicinal values.