Antimalarial and Antioxidant Activities of Sub-fractions of Capsicum frutescens L. in Plasmodium berghei-Infected Mice

Oxidative stress induced by malaria parasites significantly impacts the host microenvironment, exacerbated by resistance to existing antimalarial agents. This has prompted malaria-endemic settlements—especially those in sub-Saharan settlements—to adopt medicinal plants for the treatment of fever and malaria since they are readily available and affordable. This research evaluated the antimalarial and antioxidant activities of sub-fractions of Capsicum frutescens L. fruit (CFL) in Plasmodium berghei (NK65)-parasitized mice as potential leads for antimalarial drug development. Maintaining the same controls for the sub-fractions, combined sexes of 85 mice weighing 23.7±3.5 g were randomly grouped into seven (n=5) and inoculated intraperitoneally by 0.2 mL parasitized erythrocytes. Group A received 10 mL/kg normal saline (control), Group B received 10 mg/kg chloroquine, while Groups C to G received 0.5, 1.0, 2.0, 4.0, and 8.0 mg/kg body weight per sub-fraction, respectively. On 6 and 10 days post-inoculation (dpi), mice per group were euthanized. The in vivo test, selenium, vitamins C and E levels, 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide ion, and peroxide ion-scavenging concentrations, as well as ferric-reducing antioxidant power (FRAP), were done using standard procedures. Treatment with CLF sub-fractions revealed low parasite clearance on 6 dpi but significantly suppressed parasites (p<0.05) on 10 dpi for the three sub-fractions and increased survival in mice. This was more pronounced in sub-fraction B (SFB). Out of the three sub-fractions, SFB compared favourably with butylated hydroxytoluene (BHT) for the scavenging activities of DPPH, peroxide ion, and superoxide ion, as well as the FRAP. This efficacy of SFB was also evident in the low EC50 obtained. Therefore, CFL sub-fractions—SFB in particular— possess antiplasmodial and antioxidant activities against fever and malaria, suggesting its potential as a lead fraction for developing novel plant-derived antimalarial therapies.