Phytochemicals and in vitro anti-apoptotic properties of ethanol and hot water extracts of Cassava (Manihot esculenta Crantz) peel biogas slurry following anaerobic degradation

Abstract

Abstract Background Wastes emanating from cassava (Manihot Esculenta Crantz) processing in African countries significantly contribute to environmental pollution, besides, such toxic wastes contribute to greenhouse gas emission. Although cassava peel has been successfully used as a raw material in mushroom cultivation, feedstock for livestock, biogas production but the bio-transformed products recovered from the anaerobic digestion of cassava wastes, especially the peels have often been overlooked. Therefore, this research aimed at quantifying the secondary metabolites in the slurry recovered from ethanol and hot water extraction of cassava peel subjected to biogas production, in vitro, for anti-apoptotic properties. Methods Fresh cassava peels were allowed to ferment anaerobically to produce three states of matter; gas, solid, and liquid/slurry. The slurry was extracted using 95 % ethanol and 100 oC hot water to obtain crude extracts, which were then subjected to anti-apoptotic screening using the mitochondrial swelling assay. The qualitative phytochemical analysis of the crude extracts was done using standard methods. Further characterization of the crude extracts was done by FTIR for the chemical elucidation of the functional groups present. Results The qualitative phytoconstituents revealed that the slurry extracts are naturally enriched with alkaloids, steroids, flavonoids, and saponins. The infrared spectrum of the crude extracts revealed the presence of hydroxyl, alkane, carboxyl groups in the ethanol extract, and hydroxyl, alkene, amide, carbonyl groups in the hot water extract. In the presence and absence of exogenous Ca2+, both extracts of the slurry induced liver mitochondrial permeability transition pore opening albeit at low amplitude swelling as the mean absorbance was less than one (at 540 nm). Conclusions Based on these results obtained, the crude extracts of cassava peel biogas slurry have been proven to possess bioactive compounds that could induce liver mitochondrial permeability transition pore opening, in vitro.