Bioactivity assessment of ethanolic extracts from Theobroma cacao and Cola spp. wastes after solid state fermentation by Pleurotus ostreatus and Calocybe indica

Abstract

The use of agro-industrial residues for production of bio-functional products has aroused the interest of scientists as a positive step towards ecological sustainable. In this study, Pleurotus ostreatus or Calocybe indica was used in solitary and were combined in solid state fermentation to improve bioactivities of extracts from cocoa pod husk (CPH) and kolanut pod (KP). The bioactive compounds in extracts were revealed using Gas chromatography–mass spectrometry (GCMS). Phenolic and flavonoid contents of studied extracts were within 34.80–56.9 mg/g Gallic acid equivalent and 11.50–31.5 mg/g Quercertin equivalent, respectively. Extracts from unfermented and fermented pods of Theobroma cacao and Cola spp. displayed notable antimicrobial activity against indicator microorganisms with zones of inhibition ranged from 5.0 to 18.0 mm. Minimum inhibitory concentration of the extracts against microorganisms ranged from 2.5 to 10.0 mg/ml. IC50 of extracts against free radicals ranged from 0.3 to 1.7 mg/ml, 0.4–1.7 mg/ml and 0.4–1.8 mg/ml for DPPH, Fe and OH−, respectively. Some of bioactive compounds identified using GCMS were phenol, glycerine, pimelic ketone, D-ribonic acid, methyl myristate, palmitic acid methyl ester, oleic acid ethyl ester, lauramide, oleic acid amide, 1,2-cyclododecanediol, resorcinol, phytol and others. The bioactivities of extracts from unfermented and fermented CPH and KP can be attributed to the presence of assorted bioactive compounds, which can be exploited as antimicrobial, antioxidant, anti-inflammatory, immunomodulatory, antitumor promoting agents and therefore, useful for production of functional foods, pharmaceuticals, and cosmetics.