Comparative Antiplasmodial Evaluation of the Root and Stem Bark of Caesalpinia pulcherrima: Vacuum Liquid Chromatographic Fractionation of the Root Bark and Elemental Profiling of the Stem Bark

Abstract

The persistent development of resistance to currently available antimalarial therapies underscore the urgent need
to investigate alternative bioactive agents, particularly those derived from medicinal plants. The in vivo anti
malaria properties of root and stem barks of Caesalpinia pulcherrima, a plant employed in traditional malaria
treatment in south-western Nigeria, were comparatively examined in this study. Antiplasmodial activity was
investigated in albino mice (20 to 30g) infected with chloroquine-sensitive malaria parasite, following the
established four-day suppressive protocol. Oral administration of the crude root bark extract (200–800
mg/kg/day) resulted in statistically significant and concentration-related decreases in parasitaemia, achieving
suppression values between 34.17% and 50.57% during the early phase of infection. In contrast, the methanol–
ethyl acetate stem bark extract produced comparatively greater inhibitory effects at equivalent dose levels, with
maximum parasitaemia suppression reaching 63.29%. The reference drug, chloroquine (5 mg/kg/day),
demonstrated markedly higher efficacy, producing parasitaemia reductions ranging from 86.22% to 95.22%
across the study period. Although the plant extracts were less potent than chloroquine, the stem bark
consistently exhibited stronger chemosuppressive activity than the root bark, particularly at higher administered
doses. To further investigate the phytochemical basis of activity, the crude root bark extract was subjected to
vacuum liquid chromatographic (VLC) fractionation. In addition, elemental profiling of the stem bark
performed by means of atomic absorption spectrophotometry identified essential trace and macro elements such
as iron, copper, calcium, and sodium. These minerals may play supportive roles in host metabolic and
immunological functions, potentially contributing to the observed therapeutic effects. Overall, the comparative
findings indicate that both plant parts possess appreciable in vivo antiplasmodial activity, with the stem bark
demonstrating relatively enhanced efficacy. The data provide pharmacological support for the traditional
application of C. pulcherrima in malaria management and suggest its efficacy as a promising source of
antimalarial leading substances.