Journal of Experimental Agriculture International

Aims: “This study aims to investigate the production of secondary metabolites of P. odontadenius against malaria using some concentrations of sodium azide (NaN₃) and to choose those with high in vitro antimalarial activities.”

Study Design: Laboratory experiment tests; Identification of plant material, Immersion of seeds in SA concentrations, In vitro culture of seeds, In situ culturing plantlets, Extraction of Phyllanthus odontadenius aerial parts, Phytochemical screening, in vitro antiplasmodial tests to determine the inhibition of concentration killing 50% of parasite population (IC₅₀).

Place and Duration of Study: Department of Biotechnology and Molecular Biology, Department of Biochemistry: General Atomic Energy Commission, Regional Center of Nuclear Studies, P.O. Box. 868 Kinshasa XI, Democratic Republic of the Congo (DRC). National Institute of Biomedical Research (NIBR) at Kinshasa/Gombe (DRC). The experiments were conducted firstly during August and December 2011 and secondarily during May and September 2012.

Methodology: Seeds of P. odontadenius were obtained after oven drying at 45°C and they were immersed in SA at concentrations ranging firstly between 0 to 10 mM; secondarily between 0 to 20 mM. Seeds were germinated on Murashige and Skoog medium (MS) and plantlets were transferred in situ. In addition some parameters such as height, collar diameter, number of branches and biomass from first generation were analyzed. Phytochemical screening was released. The in vitro antiplasmodial activities assays on clinical isolates of P. falciparum was determined.

Results: Results showed that SA had positive effects on growth parameters of P. odontadenius in the M1 generations with greater effects observed with treatment exceeding 10 mM. For the in vitro antimalarial activities from to extracts obtained with aerial material parts from directly immersed seeds (M1), the effects observed with plant extracts from seeds dipped in SA were higher than those from untreated seeds. IC₅₀ values were ranged between 1.04±0.02 μg/ml (10 mM) to 12.77±5.83 μg / ml (0 mM) for the first assay. And for the second test, the in vitro antiplasmodial activities varied between 1.47±1.07 μg/ml (10 mM) to 21.60±7.13 μg/ml (2.5 mM). The best activities were observed with SA solutions exclusive of 5 mM to 10 mM. The SA lethal doses were 4.76 mM for LD₃₀ and 10.99 mM for LD₅₀.

Conclusion: Treatment of P. odontadenius seeds with SA induced stimulation of parameters which increase linearly with increasing concentrations of SA. Some secondary metabolites were synthesized for example alkaloids compounds compared to the untreated seeds of                         P. odontadenius with a more important synthesis in phenolic compounds. The in vitro antiplasmodial activities on the clinical isolates P. falciparum showed low antimalarial activities from M1 controls (0 mM) than that of extracts from treated plants. The high inhibitory effects (1,04±0.02  µg/mL or 1.47±1.07 µg/mL for 10 mM) of crude extracts plants from treated seeds have justified the usefulness of SA in plant breeding particularly in the increasing production of secondary metabolite against malaria in the World.