Phytochemical Investigation and Antifibrinolytic Properties of Sorghum bicolor Leaf Sheaths: Towards Developing a Plant-Based Haemostatic Agent for Rural Nigeria

Haemorrhage remains a significant cause of preventable mortality in rural Nigeria, particularly in trauma, obstetric, and surgical contexts where access to blood products and pharmaceutical haemostatic agents is severely limited. Sorghum bicolor leaf sheaths have been used across the North West and North Central zones of Nigeria by traditional healers for wound bleeding control, yet their haemostatic mechanisms are entirely uncharacterised. This PhD research investigates the phytochemical composition and antifibrinolytic haemostatic mechanisms of Sorghum bicolor leaf sheath extracts as part of a phased translational development programme towards a viable plant-based haemostatic agent for rural Nigeria. Systematic phytochemical profiling by UHPLC-HRMS and NMR characterisation identified procyanidin oligomers, apigenin glycosides, luteolinidin (an unusual 3-deoxyanthocyanidin), and phenolic acids as the dominant compound classes. In vitro antifibrinolytic mechanisms were investigated by tissue plasminogen activator (tPA)-induced clot lysis inhibition, plasmin activity assay, fibrinogen polymerisation kinetics, and platelet aggregation potentiation using platelet-rich plasma. In vivo haemostatic activity was evaluated in a rat tail transection model and a liver laceration model. Extract at 400 mg/kg significantly prolonged clot lysis time, inhibited plasmin activity, and accelerated fibrinogen polymerisation. Luteolinidin was identified as the primary antifibrinolytic constituent through bioassay-guided correlation. An optimised topical haemostatic powder formulation was developed and characterised for particle size, moisture, and haemostatic performance. This work contributes foundational pharmacognostic data for the development of a culturally relevant, locally sourced haemostatic product for rural Nigerian healthcare. Keywords: Sorghum bicolor, haemostatic, antifibrinolytic, luteolinidin, rural Nigeria