Exploration of Antioxidant and Antimicrobial Potential of Agro-industrial and Spent Waste of Camellia Sinensis

Abstract

The objective of this research was to assess the value-added potential of agro-industrial and spent black tea waste (SBTW) as a source of antimicrobial and antioxidant phenolic compounds. The influence of extraction solvent (water, ethanol, acetone and Water: ethanol = 60:40) and sample (farm waste [FW], industrial tea waste [ITW] and SBTW) and their relations on the antimicrobial and antioxidant action of the extracts were explored. Among the several extracts of FW, the acetone extract showed the highest antioxidant activity of 72.09 ± 0.35%. Aqueous extract of SBTW gave 59.30 ± 0.354% antioxidant activity. The only extract of ITW that had shown the antioxidant activity was ethanol extract with 1.16 ± 0.25% of this activity. Acetone extract of FW exhibited the highest antimicrobial activity for all investigated pathogens viz. Streptococcus sp (19.3 ± 0.35 mm), Corynebacterium sp (9.3 ± 0.25 mm) and Staphylococcus aureus (3.3 ± 0.25 mm). The antimicrobial activity of acetone extract of SBTW against Corynebacterium sp and Streptococcus sp was found significant (13.33 ± 0.35 mm). The only extracts of ITW that demonstrated antimicrobial activity were ethanol and acetone extract that showed the zone of inhibition of 8.6 ± 0.20 mm and 2.6 ± 0.10 mm for Corynebacterium sp and S. aureus respectively. Flavonoids and phenols were detected in all extracts of FW and SBTW except in the ethanol extracts of latter. Tannins were found in all the extracts of FW, ITW and SBTW except their acetone extracts. Coumarin was detected only in ethanol extracts of FW, ITW and SBTW. The important bioactive components present in the acetone extract of FW of Camellia sinensis were 4-Phenylbut-3-ene-1-yne, 1-Tridecene, Biphenyl, 1-Pentadecene, 8-Pentadecanone, 1-Nonadecene, Neophytadiene, Caffeine, 1-Nonadecene, 4-Oxazolecarboxylic acid, 4,5-dihydro-2-phenyl-, 1-methylethyl ester, Phytol, 1-Heptacosanol, Decanedioic acid, alpha Tocospirone B, Pentatriacontane, Vitamin E, Stigmasta etc. They are known antioxidants and antimicrobials and are of industrial engrossment. Moreover, phenolic compounds hold antimicrobial action against pathogenic bacteria, making them effective preservatives for prolonging the shelf life of foods and inhibiting the growth of foodborne pathogens, as well as anticancer properties, making them valuable assets in several industries, incorporating pharmaceuticals, food, and cosmetics.