An In vivo Antiplasmodial Activity of Aqueous and Ethanol Crude Plant Extracts of Phyllanthus fraternus Using Plasmodium berghei Infected balb/c Mice

Background: Phyllanthus fraternus is a tropical plant that has numerous pharmacological activities such as blennorrhagia, colic, diabetes, dysentery, fever, flu, tumours, jaundice, vaginitis, dyspepsia, anti-inflammatory, antioxidant, anticoagulant, anti-diabetic, antiviral and analgesic. The study evaluated in vivo anti-plasmodial activity of aqueous and ethanol crude plant extracts of Phyllanthus fraternus using Plasmodium berghei infected Balb/c mice.

Methodology: The preparation of the aqueous crude extract was done by boiling 195 g of the dried plant material in 4 L of water for 30 minutes and cooled. The resultant extract was filtered through a cotton wool and put in an oven at 50°C to concentrate it before it was pre- freeze and lyophilized into powder using a freeze dryer (Heto powder dry LL 300, Sapa). Similarly the preparation of the ethanol crude extract was obtained by simple maceration of 195 g of dried sample of the plant in 2 L aqueous ethanol (1.4 L of ethanol plus 0.6 L of distilled water) for 72 h. It was then filtered through cotton wool and subjected to rotary evaporator (ILA CCA-1111 Japanese branch) to evaporate the ethanol and then pre-freeze and freeze- dried. The crude extracts were screened for their phytochemical constituents which showed the presence of secondary metabolites. The LD50 of both extracts were investigated using Sprague-Dawley rats and found to be greater than 5000 mg/kg. The in vivo antiplasmodial activity (percentage parasitaemia (%P) and the percentage chemo-suppression (%C)) of the extracts were evaluated using Balb/c mice.

Results: The aqueous and ethanol extracts established modest antiplasmodial activity in a dose dependent manner. The standard drug (coartem 2 mg/kg) with percentage parasitaemia (%P) of 28.57±4.70 and 2.48±0.48 caused percentage chemosupression (%C) of 44.38±7.63 and 81.27±2.07 in day four and six respectively. The test groups (aqueous and ethanol extracts) for two different doses (100 mg/kg and 200 mg/kg) each administered with percentage parasitaemia (%P) 39.67±1.35, 39.58±1.64, 37.32±2.37, 36.23±1.99 and 10.24±1.32, 9.33±0.66, 8.61±0.96, 7.27±1.26 caused percentage chemosuppressions (%C) of 22.78±2.20, 22.96±2.66, 27.35±3.84, 29.48±3.23 and 22.54±9.93, 29.43±4.99, 34.87±6.66, 44.99 ±5.98 in day four and six respectively. The aqueous extract demonstrated better inhibition of plasmodium in doses 100 mg/kg and 200 mg/kg with chemosuppressions (27.35 ± 3.84 and 29.48 ± 3.23) respectively compared with the ethanol extract of the same doses 100 mg/kg and 200 mg/kg with chemosuppressions (22.78 ± 2.20 and 22.96 ± 2.66) respectively. The activity of the standard drug, coartem at 2.0 mg/kg was significantly higher (p< 0.05) with chemosupression (44.38±7.63) than those of the extracts. The extracts were also screened for phytochemicals for which some were found in the extracts which have previously been implicated as antiplasmodial agents. The LD50 of both extracts were investigated and found to be greater than 5000 mg/kg.

Conclusion: The aqueous and ethanol crude plant extracts of P. fraternus possess antiplasmodial activity and would be useful in the search for novel antimalarial agents.