In vivo Antiplasmodial Assessment of Phyllanthus odontadenius against Plasmodium berghei in NMRI Mice

Aims: Phyllanthus odontadenius is one of the genus Phyllanthus species, used for number diseases treatment including malaria. Malaria today poses a real public health problem for more than hundred countries, afflicted millions people and killed an estimated 405 000 in the World. The chemoresistance of Plasmodium falciparum to modern antimalarials which are either expensive, toxic or ineffective leads to the search for new antimalarials at lower cost, non-toxic and effective within plant biodiversity. Given the interest in various P. odontadenius crude extracts in vitro on P. falciparum, an in vivo study seems necessary in order to judge the extracts effectiveness of this plant. This study therefore aims to find justification for P. odontadenius secondary metabolites antiplasmodial activity which would have been revealed in the three samples from three different province sites.

Study Design: Plants P. odontadenius samples from three province harvested and dried separately, plant phytochemistry screening realized, extracts preparation for antiplasmodial test, mice parasitization with P. berghei strain, orally administration drug; Parasiteamia determination using an immersion microscope.

Place and Duration of Study: Department of Radiobiology, Applied Microbiology section, General Atomic Energy Commission, Regional Nuclear Studies Center of Kinshasa. MPI and pharmacognosy laboratories in the National Biomedical Research Institute (INRB). This work took place over the period from October 11, 2020 to March 12, 2021.

Methodology: Phytochemical screening P. odontadenius samples was previously determined with the chemical reagent reactions and TLC. Then, P. odontadenius methanol extracts from aerial parts harvested in three sites (Kinshasa, Kasangulu and Kwango-bridge) were administered to test mice (12.5 mg/kg and 25 mg//kg bw) after infected mice with the Plasmodium berghei strain. DMSO 10% and quinine 10 mg/kg bw were also used as controls for comparison with the samples of P. odontadenius extracts. After 5 days, parasitemia of each test and controls mice was determined. Percent of parasitemia, parasite density and percent of inhibition were calculated. Finally, the effect dose 50 of each P. odontadenius specimen was finally determined.

Results: Parasiteamia rates of negative control (DMSO 10%) was high (69.98±15.03%) comparing to positive control (27.43±11.46%) and tested mice with P. odontadenius extracts (12.5 and 25 mg/kg bw) which percent’s varied from 24.66±15.84% to 59.01±22.44%. Negative control presented high parasite density with 11,342 (±2,436) comparing to the positive control (4,447±1,857) and all P. odontadenius methanol extracts which varied from 3,995±2,343 for 25 mg/kg bw to 9,570±3,319 for 12.5 mg/kg bw. Parasiteamia reduction rates followed inversely parasite density, thus, Po3 25 mg/kg bw had high parasiteamia reduction rate (65.23%) comparing to positive control with 61.32% and to P. odontadenius methanol extracts. Po3 presented 2.44 mg/kg bw as effect dose 50 comparing to Po1 (2.93 mg/kg bw) and Po2 (2.68 mg/kg bw). Males mice were highly affected to P. berghei than the females.

Conclusion: This study revealed that all specimens of P. odontadenius had good in vivo antiplasmodial activities on P. berghei. All P. odontadenius extracts showed good parasitaemia inhibition compared to negative control, but P. odontadenius from Kwango-brigde (Po3) presented good behavior concerning in vivo antiplasmodial activity in comparison to P. odontadenius from Kasangulu (Po2) and that from Kinshasa (Po1). However, further studies are necessary on the in vivo toxicity of the plant and on the medicinal form that could be applied.