Antioxidant, Antibacterial, and Cytotoxicity Activities of Cashew (Anacardium occidentale) Nut Shell Waste

Abstract

Context: Antioxidants have been used in the food industry particularly as dietary supplements and additives to preserve food quality during transportation and storage. In the Southern of Thailand, especially in Ranong Province, cashew nut is one major of agriculture product and the volume of cashew nut shell is becoming increase as by-product. Aims: The aim of this study is to evaluate antioxidant activity, antibacterial activity against to common food borne pathogens, and cytotoxicity to mammal cells of cashew nut shell waste. Materials and Methods: Antioxidant activity of cashew nut shell waste was 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) cation radical scavenging assays. Evaluation of antibacterial activity of water extract (CW) and ethanol extract (CE) of cashew nut shell waste was done against Staphylococcus aureus, Bacillus cereus, Enterococcus faecium, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumanii by resazurin microplate assay (REMA). Cytotoxicity of CW and CE was determined by REMA and used human dermal fibroblasts, a neonatal (HDFn)–neonatal dermal fibroblast and Vero cells as mammal cells. Results and Discussion: Cashew nut shell waste extract (150 μg/ml) was inhibited DPPH and ABTS radical by 75.5 ± 1.4 and 97.1 ± 1.4%, which calculated to 57.1 ± 1.0 and 56.2 ± 0.6 μmol trolox equivalent antioxidant capacity, respectively. Water (CW) and ethanol (CE) extracts of cashew nut shell waste were inhibited S. aureus, B. cereus, and E. faecium with minimal inhibitory concentration = 3.13, 3.13, and 6.25 μg/ml, respectively. CW and CE (3.13-100 μg/ml) were insufficient cytotoxic against Vero cells and HDFn-neonatal dermal fibroblast. Conclusions: Cashew nut shell waste may apply for food additives used, as well as, to reduce or diminish agricultural waste production.