BIOACTIVITY AND BIOSAFETY ASSESSMENT OF CASSIA ABBREVIATA

Cancer presents an escalating public health crisis and a significant barrier to life expectancy in Zimbabwe. Conventional oncological treatments face severe constraints in domestic healthcare facilities due to limited funding, diagnostic equipment deficits, and unreliable medicine supply chains. This study evaluates the phytochemical profile, in-vivo acute oral safety, and in-vitro anti-inflammatory and antioxidant bioactivities of crude bark extracts from Cassia abbreviata Oliv. Cassia abbreviata bark was sustainably harvested from Murehwa, Mashonaland East, using the selective bark stripping method to ensure cambium regeneration. Hydro-ethanolic extracts were prepared via a standardized three-day maceration process and concentrated under reduced pressure using a rotary evaporator. Preliminary phytochemical screening was conducted via colorimetric tube tests (Wagner’s, Ammonia, Ferric Chloride, Salkowski’s, and Foam tests) to identify key secondary metabolites. Metabolic constituents were further mapped using Thin-Layer Chromatography (TLC) on silica gel plates developed with a dichloromethane and ethanol (96:4) mobile phase. Biosafety profiling was rigorously executed through an in-vivo acute oral toxicity study in rat models following OECD Guideline 425 over a 14-day monitoring period. Pharmacological bioactivity was quantified using an in-vitro egg albumin denaturation anti-inflammatory assay against a standard diclofenac positive control. Hydro-ethanolic maceration of the bark yielded 34.4 g of dry extract from 450 g of starting material. Phytochemical and TLC screening confirmed an abundance of bioactive secondary metabolites, including alkaloids, flavonoids, tannins, saponins, terpenoids, and phenolic compounds. In the in-vivo biosafety profiling, oral administration of the extract at escalating single doses up to 5000 mg/kg of body weight resulted in zero mortality or morbidity. All fundamental biological functions remained. The median lethal dose was determined to be greater than 5000 mg/kg, classifying the matrix as practically non-toxic. Regarding bioactivity, the extract displayed potent, dose-dependent anti-inflammatory effects by inhibiting protein denaturation, initiating at 32% inhibition (50 µg/ml) and peaking at 80% inhibition at a concentration of 1000 µg/ml. The findings validate that Cassia abbreviata bark extracts possess an exceptionally high safety margin and are non-toxic up to maximum acute thresholds.