Journal of Pharmaceutical Research International

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.