Evaluation of antiplasmodial effects of the ethanolic leaf extract of Salacia lehmbachii on Plasmodium berghei infected mice

Salacia lehmbachii leaves are used in Nigerian traditional medicine for the treatment of malaria and other diseases. The ethanolic extract was tested for its activities against suppressive, prophylactic and established infections in Plasmodium berghei infected albino mice at dose levels of 100, 200 and 400 mg/kg; while chloroquine (10 mg/kg) was used as positive control. The extract exhibited significant dose-related antiplasmodial activities on parasites with the used-dose levels, showing significant mean survival time. The results, therefore, co-relate with claims by traditional users for the treatment of malaria and other feverish conditions; and could serve as source of potential new antimalarial  agents. DOI: http://dx.doi.org/10.5281/zenodo.55610

Acute toxicity, brine shrimp cytotoxicity and relaxant activity of fruits of callistemon citrinus curtis

<p>Abstract</p> <p>Background</p> <p><it>Callistemon citrinus </it>Curtis belongs to family Myrtaceae that has a great medicinal importance. In our previous work, fruits of <it>Callistemon citrinus </it>were reported to have relaxant (antispasmodic) activity. The current work describes the screening of fractions of the crude methanol extract for tracing spasmolytic constituents so that it shall help us for isolation of bioactive compounds. Acute toxicity and brine shrimp cytotoxicity of crude methanol extract are also performed to standardize it.</p> <p>Methods</p> <p>The crude methanol extract was obtained by maceration with distilled water (500 ml) three times and fractionated successively with <it>n-</it>hexane, chloroform, ethyl acetate and <it>n-</it>butanol (300 ml of each solvent). Phytochemical analysis for crude methanol extract was performed. Acute toxicity studies were performed in mice. Brine shrimp cytotoxicity studies were performed to determine its cytotoxicity and standardize it. In other series of experiments, rabbits' jejunum preparations were used in screening for possible relaxant activities of various fractions. They were applied in concentrations of 0.01, 0.03, 0.1, 0.3, 1.0, 3.0, 5.0 and 10.0 mg/ml on spontaneous rabbits' jejunum preparations. In similar fashion, fractions were also tested on KCl (80 mM) -induced contractions. Calcium chloride curves were constructed in K-rich Tyrode's solution. The effects of various fractions were tested on calcium chloride curves at concentrations 1.0, 3.0, 5.0 and 10.0 mg/ml. Curves of verapamil used as reference drug at concentration 0.1 μM and 0.3 μM were also constructed. The curves were compared with their respective controls for possible right shift.</p> <p>Results</p> <p>Methanol extract tested strongly positive for saponins and tannins. However, it tested mild positive for presence of proteins, amino acids, carbohydrates and phenolic compounds. LD₅₀value for crude methanol extract is 476.25 ± 10.3 (470-481, n = 4) mg/ml. Similarly, EC₅₀value for brine shrimp cytotoxicity is 65.5 ± 7.28 (60.8- 69.4, n = 4) mg/ml. All the fractions relaxed the spontaneous and KCl-induced contractions. EC₅₀values (mg/ml) for effects of ethyl acetate fraction on spontaneous and KCl induced contractions are 2.62 ± 0.78 (2.15-3.0, n = 4) and 3.72 ± 0.86 (3.38-4.28, n = 4) respectively. Respective EC₅₀values (mg/ml) for <it>n-</it>butanol fraction are 3.59 ± 0.2(3.07-3.9, n = 4) for spontaneous, and 5.57 ± 0.2 (5.07-6.11, n = 4) for KCl- induced contractions. EC₅₀value for control calcium chloride curve (without extract) is -2.73 ± 0.19 (-2.6 - -2.81, n = 4) while EC₅₀for curves treated with 5.0 mg/ml of chloroform is -2.22 ± 0.02 (-2.16 - -2.3, n = 4). EC₅₀value for ethyl acetate treated (1.0 mg/ml) tissues is -1.95 ± 0.10 (-1.88 - -2.0, n = 4) <it>vs</it>. control EC₅₀= -2.71 ± 0.08 (-2.66 - -2.76, n = 4). All the fractions, except <it>n-</it>hexane, showed a right shift like that of verapamil (EC₅₀= -1.72 ± 0.15 (-1.62 - -1.8, n = 4) vs. Control EC₅₀= -2.41 ± 0.06 (-2.38 - - 2.44, n = 4), a standard drug that blocks voltage operated calcium channels.</p> <p>Conclusion</p> <p>Relaxant constituents were more concentrated in ethylacetate fraction followed by chloroform, <it>n -</it>butanol and aqueous fractions that warrant for its isolation. The crude methanol extract is safe at concentration 250 mg/ml or below and results of brine shrimp cytotoxicity assay imply the plant specie may be a source of cytotoxic agents.</p

Evaluation of antiplasmodial effects of the ethanolic leaf extract of Salacia lehmbachii on Plasmodium berghei infected mice

Salacia lehmbachii leaves are used in Nigerian traditional medicine for the treatment of malaria and other diseases. The ethanolic extract was tested for its activities against suppressive, prophylactic and established infections in Plasmodium berghei infected albino mice at dose levels of 100, 200 and 400 mg/kg; while chloroquine (10 mg/kg) was used as positive control. The extract exhibited significant dose-related antiplasmodial activities on parasites with the used-dose levels, showing significant mean survival time. The results, therefore, co-relate with claims by traditional users for the treatment of malaria and other feverish conditions; and could serve as source of potential new antimalarial  agents. DOI: http://dx.doi.org/10.5281/zenodo.55610