Gymnema inodorum Leaf Extract Improves Cardiac Function in Experimental Mice Infected with Plasmodium Berghei.

Malaria-associated cardiac injury has been reported to be the primary cause of death due to severe malaria. The discovery of substances showing a protective effect on cardiac injury during malaria infection is urgently needed. Hence, the purpose of this study was to evaluate the efficacy of Gymnema inodorum leaf extract (GIE) on cardiac function in mice infected with Plasmodium berghei. ICR mice were treated with 1 × 107 infected red blood cells of P. berghei ANKA (PbANKA), administered orally with GIE in 100, 250 and 500 mg/kg body weight of mice. Creatine phosphokinase (CPK) and echocardiography were carried out. It was found that CPK and heart-weight to body-weight (HW/BW) ratios were significantly higher in untreated mice than the healthy control. Moreover, impaired cardiac function in the untreated group was observed as indicated by changes in echocardiography. Interestingly, GIE exerted a protective effect on cardiac injury induced by PbANKA infection. Our results demonstrated that the parasitemia percentage, CPK, HW/BW ratio, and echocardiography in GIE treated mice were improved. However, there was no significant difference between GIE dosages. Therefore, GIE possessed a cardio-protective effect during malaria infection in mice.

Synergistic antimalarial treatment of Plasmodium berghei infection in mice with dihydroartemisinin and Gymnema inodorum leaf extract.

BACKGROUND: Chemotherapy is crucial in the fight against malaria. The rise of resistance to most antimalarial medicines has been a serious hurdle to effective treatment. Artemisinin-based combination therapies (ACTs) are currently the most effective antimalarial medication. Malaria parasites are growing more resistant to ACTs, particularly in Southeast Asia. As a result, effective alternative antimalarials are in high demand. The leaf extract of Gymnema inodorum (GIE) has previously shown promise as an effective antimalarial. Therefore, this study evaluated the antimalarial potential of combination dihydroartemisinin (DHA) and GIE therapy against Plasmodium berghei in a mouse model. METHODS: The medications were evaluated using the standard 4-day test for determining the 50% effective dosage (ED50) of DHA and GIE on P. berghei ANKA (PbANKA). DHA and GIE were combined using a fixed-ratio approach, with DHA/GIE ED50s of 100/0, 80/20, 60/40, 40/60, 20/80, and 0/100, respectively. RESULTS: The ED50 against PbANKA was determined to be 2 mg/kg of DHA and 100 mg/kg of GIE. The 60/40 (DHA/GIE) ratio demonstrated significantly higher antimalarial activity than the other ratios (p < 0.001) against PbANKA, with 88.95% inhibition, suggesting synergistic efficacy (combination index (CI) = 0.68695). Furthermore, this ratio protected PbANKA-infected mice against loss of body weight and packed cell volume decline, leading to a longer survival time over 30 days. CONCLUSION: Our results suggest that GIE could be an effective adjuvant to DHA that can enhance the antimalarial effects in the treatment of PbANKA-infected mice.

Evaluation of Antimalarial Potential of Aqueous Crude Gymnema Inodorum Leaf Extract against Plasmodium berghei Infection in Mice.

Malaria is still a serious cause of mortality and morbidity. Moreover, the emergence of malaria parasite resistance to antimalarial drugs has prompted the search for new, effective, and safe antimalarial agents. For this reason, the study of medicinal plants in discovering new antimalarial drugs is important and remains a crucial step in the fight against malaria. Hence, this study is aimed at investigating the antimalarial activity of Gymnema inodorum leaf extract (GIE) in Plasmodium berghei infected mice. Aqueous crude extract of G. inodorum leaves was prepared in distilled water (DW) and acute toxicity in mice was carried out. The antimalarial activity was assessed in the five groups of ICR mice employing the 4-day suppressive and curative tests. Untreated and positive controls were given DW along with 10 mg/kg of chloroquine, respectively. Any signs of toxicity, behavioral changes, and mortality were not observed in mice given GIE up to 5,000 mg/kg. GIE significantly (P < 0.05) suppressed parasitemia by 25.65%, 38.12%, and 58.28% at 10, 50, and 100 mg/kg, respectively, in the 4-day suppressive test. In the curative test, the highest parasitemia inhibition of 66.78% was observed at 100 mg/kg of GIE. Moreover, GIE prevented packed cell volume reduction and body weight loss compared to the untreated control. Additionally, GIE was able to prolong the mean survival time of infected mice significantly. The results obtained in this study confirmed the safety and promise of G. inodorum as an important source of new antimalarial agents and justify its folkloric use for malaria treatment.

Hypoglycemia induced by Plasmodium berghei infection is prevented by treatment with Tinospora crispa stem extract.

During Plasmodium malaria parasite infection in a human, the intraerythrocytic stages lead to the clinical manifestations of the disease, especially hypoglycemia. Hypoglycemia is a recognized feature of severe malaria and linked with a high risk of mortality for children. Hence, the present study aimed to investigate the protective effect of T. crispa stem extract on hypoglycemia induced by P. berghei infection tested with a mouse model. ICR mice were inoculated with 1 × 107 parasitized erythrocytes of P. berghei ANKA (PbANKA) by intraperitoneal injection and given 50, 100, and 200 mg/kg of ethanolic extract for 4-consecutive days. The results showed that T. crispa stem extract exerted a protective effect (100%) on hypoglycemia induced by PbANKA infection at doses of 100 and 200 mg/kg. A significantly (p < .05) prolonged mean survival time (28.0 ±â€¯1.9 days) of the extract treated mice was also observed. Additionally, no effect on blood glucose levels was seen in normal mice treated with all doses of extract. It can be concluded that T. crispa stem extract may have beneficial properties in protecting against hypoglycemia, and in increasing survival time during malaria infection.

Antimalarial Properties of Aqueous Crude Extracts of Gynostemma pentaphyllum and Moringa oleifera Leaves in Combination with Artesunate in Plasmodium berghei-Infected Mice.

Due to the emergence and spread of malaria parasite with resistance to antimalarial drugs, discovery and development of new, safe, and affordable antimalarial are urgently needed. In this respect, medicinal plant extracts are targets to optimize antimalarial actions and restore efficacy of standard antimalarial drugs. The present study was aimed at determining the antimalarial activities of Gynostemma pentaphyllum and Moringa oleifera leaf extracts in combination with artesunate against Plasmodium berghei-infected mice. P. berghei ANKA maintained by serial passage in ICR mice were used based on intraperitoneal injection of 1 × 107 parasitized erythrocytes and subsequent development of parasitemia. These infected mice were used to investigate the antimalarial activity of artesunate (6 mg/kg) in combination with 500, 1,000, and 2,000 mg/kg of G. pentaphyllum and M. oleifera leaf extracts using 4-day suppressive test. It was found that these extracts showed significant (P < 0.05) antimalarial activity in dose-dependent manner with percentage of suppression of 45, 50, and 55% for G. pentaphyllum leaf extract and 35, 40, and 50% for M. oleifera leaf extract. Additionally, artesunate combined with these extracts presented higher antimalarial activity, compared to extract treated alone with percentage of suppression of 78, 91, and 96% for G. pentaphyllum leaf extract and 73, 82, and 91% for M. oleifera leaf extract. The results indicated that combination treatment of G. pentaphyllum or M. oleifera leaf extracts with artesunate was able to increase the antimalarial activity by using low dose of artesunate. Hence, these results justified the combination of these extracts and artesunate in antimalarial herbal remedies.

Protective Effect of Aqueous Crude Extract of Neem (Azadirachta indica) Leaves on Plasmodium berghei-Induced Renal Damage in Mice.

Malaria is a major public health problem in the world because it can cause of death in patients. Malaria-associated renal injury is associated with 45% of mortality in adult patients hospitalized with severe form of the disease. Therefore, new plant extracts to protect against renal injury induced by malaria infection are urgently needed. In this study, we investigated the protective effect of aqueous crude extract of Azadirachta indica (neem) leaves on renal injury induced by Plasmodium berghei ANKA infection in mice. ICR mice were injected intraperitoneally with 1 × 10(7) parasitized erythrocytes of PbANKA, and neem extracts (500, 1,000, and 2,000 mg/kg) were given orally for 4 consecutive days. Plasma blood urea nitrogen (BUN) and creatinine levels were subsequently measured. Malaria-induced renal injury was evidenced as marked increases of BUN and creatinine levels. However, the oral administration of neem leaf extract to PbANKA infected mice for 4 days brought back BUN and creatinine levels to near normalcy, and the highest activity was observed at doses of 1,000 and 2,000 mg/kg. Additionally, no toxic effects were found in normal mice treated with this extract. Hence, neem leaf extract can be considered a potential candidate for protection against renal injury induced by malaria.

Protective effect of Thunbergia laurifolia extract on hemolysis during Plasmodium berghei infection.

This study was aimed to investigate the efficacy of Thunbergia laurifolia leaf extract to protect hemolysis in mice infected with Plasmodium berghei. Aqueous leaf extract of T. laurifolia was freshly prepared, and total polyphenol was then measured using Folin-Ciocalteu reagent method. For in vivo test, ICR mice were given intraperitoneally with this extract (1,000 mg/kg) once a day for four consecutive days and subsequently inoculated with 1 × 10(6) parasitized erythrocytes of P. berghei ANKA by intraperitoneal injection for 8 days. The results showed that hemolysis was inhibited as indicated by %hematocrit (%Hct) which was normal in infected mice treated with T. laurifolia extract. Untreated and pyrimethamine-treated controls showed decreasing %Hct. Moreover, no any toxic signs were observed in normal mice treated with this extract. We conclude that T. laurifolia leaf extract clearly protects hemolysis during P. berghei infection in mice.

Protection of renal function by green tea extract during Plasmodium berghei infection.

Impairment of renal function from oxidative stress during malaria infection is one of the leading causes of death in endemic areas. Since blood urea nitrogen and creatinine levels in plasma can be used as markers for monitoring renal damage, this study investigated the effect of green tea extract on reduction of blood urea nitrogen and creatinine levels during malaria infection using Plasmodium berghei ANKA infected mice as in vivo model. For in vivo testing, ICR mice were infected with 1 × 10(7) parasitized erythrocytes and green tea extract was subsequently administered orally twice a day for 10 consecutive days. Parasitemia was estimated by standard microscopy, and blood urea nitrogen and creatinine levels in plasma were also measured. It was found that parasitemia kept increasing until animal death, and is strongly correlated with high blood urea nitrogen and creatinine. The highest levels of blood urea nitrogen and creatinine in plasma were found on day 10 after infection. However, blood urea nitrogen and creatinine levels in plasma were reduced and decreased significantly (p<0.01) in green tea extract treated mice, compared with untreated group. It can be concluded that green tea extract can protect and maintain renal function during malaria infection, and this extract can be developed for use as a supplement and combination therapy.

Transgenic Plasmodium parasites stably expressing Plasmodium vivax dihydrofolate reductase-thymidylate synthase as in vitro and in vivo models for antifolate screening.

BACKGROUND: Plasmodium vivax is the most prevalent cause of human malaria in tropical regions outside the African continent. The lack of a routine continuous in vitro culture of this parasite makes it difficult to develop specific drugs for this disease. To facilitate the development of anti-P. vivax drugs, bacterial and yeast surrogate models expressing the validated P. vivax target dihydrofolate reductase-thymidylate synthase (DHFR-TS) have been generated; however, they can only be used as primary screening models because of significant differences in enzyme expression level and in vivo drug metabolism between the surrogate models and P. vivax parasites. METHODS: Plasmodium falciparum and Plasmodium berghei parasites were transfected with DNA constructs bearing P. vivax dhfr-ts pyrimethamine sensitive (wild-type) and pyrimethamine resistant (mutant) alleles. Double crossover homologous recombination was used to replace the endogenous dhfr-ts of P. falciparum and P. berghei parasites with P. vivax homologous genes. The integration of Pvdhfr-ts genes via allelic replacement was verified by Southern analysis and the transgenic parasites lines validated as models by standard drug screening assays. RESULTS: Transgenic P. falciparum and P. berghei lines stably expressing PvDHFR-TS replacing the endogenous parasite DHFR-TS were obtained. Anti-malarial drug screening assays showed that transgenic parasites expressing wild-type PvDHFR-TS were pyrimethamine-sensitive, whereas transgenic parasites expressing mutant PvDHFR-TS were pyrimethamine-resistant. The growth and sensitivity to other types of anti-malarial drugs in the transgenic parasites were otherwise indistinguishable from the parental parasites. CONCLUSION: With the permanent integration of Pvdhfr-ts gene in the genome, the transgenic Plasmodium lines expressing PvDHFR-TS are genetically stable and will be useful for screening anti-P. vivax compounds targeting PvDHFR-TS. A similar approach could be used to generate transgenic models specific for other targets of interest, thus facilitating the development of anti-P. vivax drugs in general.