Antioxidant and cytotoxic activities of protein hydrolysates from shrimp shell wastes, germinated soybean and pigeon pea flour blends: A mixture response surface methodology approach

Abstract

Cancer has high prevalence rate and mortality with conventional chemotherapy and other management protocols being both expensive and inaccessible especially in low/medium income countries (LMIC). Sourcing alternative cheaper and easily accessible treatment from blends of antioxidants sources can reduce the burden of cancer on patients. This work therefore seeks to produce a blend from the protein hydrolysates of shrimp shell waste, germinated soybean and germinated pigeon pea which not only has high antioxidant activity but also can inhibit cervical cancer cell proliferation. In vitro antioxidant and cytotoxic activities of the mixtures of germinated pigeon pea, germinated soybean, and shrimp shell waste hydrolysates were evaluated using the mixture response surface methodology (MRSM). Fourteen blends were obtained using the simplex centroid design. Total phenolic content (TPC), 2, 2-Diphenyl-1-Picrylhydrazyl (DPPH) and % cytotoxicity of the samples were analysed. Numerical optimization was conducted with the goal of simultaneously maximizing the DPPH scavenging activity and TPC while minimizing % cytotoxicity. The optimized blend consisted of 91.06 % pigeon pea, 8.94 % shrimp shell waste and 0 % soybean. The predicted responses obtained were 74.28 % DPPH scavenging activity, 39.6 GAE mg/dL TPC and 21 % cytotoxicity. The IC50 values for the optimized blend and a standard chemotherapeutic drug were 0.260 mmol/mL and 0.013 mmol / mL respectively. This in vitro study revealed that the pigeon pea - shrimp shell waste blend, as generated by MRSM, was comparable to a standard anticarcinogenic drug with respect to potency. Keywords: pigeon pea, soybean, hydrolysates, shrimp shell waste, cytotoxicity, antioxidants, DPPH