Malaria is one of the most important infectious diseases in the world. The choice for the treatment is highly limited due to drug resistance. Hence, finding the new compounds to treat malaria is urgently needed. The present study was attempted to evaluate the antimalarial activity of the Annona muricata aqueous leaf extract in Plasmodium berghei infected mice. Aqueous leaf extract of A. muricata was prepared and tested for acute toxicity in mice. For efficacy test in vivo, standard 4-day suppressive test was carried out. ICR mice were inoculated with 107 parasitized erythrocytes of P. berghei ANKA by intraperitoneal injection. The extracts (100, 500, and 1000 mg/kg) were then given orally by gavage once a day for 4 consecutive days. Parasitemia, percentage of inhibition, and packed cell volume were subsequently calculated. Chloroquine (10 mg/kg) was given to infected mice as positive control while untreated control was given only distilled water. It was found that A. muricata aqueous leaf extract at doses of 100, 500, and 1000 mg/kg resulted in dose dependent parasitemia inhibition of 38.03%, 75.25%, and 85.61%, respectively. Survival time was prolonged in infected mice treated with the extract. Moreover, no mortality to mice was observed with this extract up to a dose of 4000 mg/kg. In conclusion, the A. muricata aqueous leaf extract exerted significant antimalarial activity with no toxicity and prolonged survival time. Therefore, this extract might contain potential lead molecule for the development of a new drug for malaria treatment.

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 × 107 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.

Oxidative stress and inflammation are 2 major contributors to numerous life-threatening disorders, including vascular pathologies. Shallots (Allium ascalonicum) are a type of red onion which grows in Southeast Asia. Bulbs of this plant are used both as a food ingredient and in traditional medicine. This study attempted to investigate the possible ways that juice extracted from Thai shallot (A.ascalonicum cv. Chiangmai) bulbs could be used in the prevention of cardiovascular complications. The antioxidative and anti-inflammatory effects of shallot juice extract (SHE) on human vascular endothelial cells (EA.hy926) were investigated. Cell viability was evaluated by MTT assay, membrane lipid peroxidation by thiobarbituric acid reactive substances assay, intracellular reactive oxygen species (ROS) production by the fluorescent probe 6-carboxy-2'-7'-dichlorofluoresceine, and interleukin-6 (IL-6) released by ELISA. The shallot juice showed extremely low cytotoxicity against EA.hy926 cells, with IC50 of 41.9 and 27.3 mg/ml for 24 h- and 48 h-incubation, respectively. SHE reduced the iron-induced malondialdehyde production in a dose-dependent manner. The extract also demonstrated antioxidant activity as shown by a significant reduction of H2O2-induced ROS production at a low concentration (< 200 mg/ml). Furthermore, SHE significantly attenuated the level of IL-6 released during lipopolysaccharide stimulation (p < 0.05). It is of interest that the juice extracted from Thai shallot bulbs demonstrated both cellular antioxidant and anti-inflammatory properties in endothelial cell models, combined with a reduction in toxicity. Shallot extract could be considered as a nutraceutical for the prevention or management of vascular diseases as it is related to oxidative stress and inflammation.

Malaria-associated hemolysis is associated with mortality in adult patients. It has been speculated that oxidative stress and inflammation induced by malaria parasite are involved in its pathophysiology. Hence, we aimed to investigate the antihemolytic effect of green tea, safflower, and mulberry extracts against Plasmodium berghei infection. Aqueous crude extracts of these plants were prepared using hot water method and used for oral treatment in mice. Groups of ICR mice were infected with 6 × 106 infected red blood cells of P. berghei ANKA by intraperitoneal injection and given the extracts (500, 1500, and 3000 mg/kg) twice a day for 4 consecutive days. To assess hemolysis, hematocrit levels were then evaluated. Malaria infection resulted in hemolysis. However, antihemolytic effects were observed in infected mice treated with these extracts at dose-dependent manners. In conclusion, aqueous crude extracts of green tea, safflower, and mulberry exerted antihemolysis induced by malaria infection. These plants may work as potential source in the development of variety of herbal formulations for malarial treatment.

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