Antioxidant property and chemical profile of pyroligneous acid from pineapple plant waste biomass

Abstract

Pyroligneous acid was produced by subjecting the stem and leaves of pineapple plants from a local plantation area to slow pyrolysis in a charcoal kiln for 48h. The concentrated pyroligneous acid from pineapple plant waste biomass (CPAP: Concentrated pyroligneous acid from pineapple waste biomass) and its dichloromethane extract (DCPAP: Dichloromethane extract of concentrated pyroligneous acid from pineapple waste biomass) was found to exhibit scavenging activity against DPPH (78.3% and 89.7%), ABTS (61.1% and 96.8%) and superoxide radical (79.3% and 85%). DCPAP exhibited higher scavenging activity than CPAP due to higher total phenolic content (9.5±0.11mg gallic acid equivalents (GAE)/g of DCPAP sample; 2.67±0.14mg GAE/g of CPAP sample). Chemical profiling by GC–MS showed that DCPAP has a high content of phenolic compounds (69.5%) especially 2,6-dimethoxy phenol, phenol, 1,2-benzenediol, 3-methoxy 1,2-benzenediol and 2-methoxy phenol which are known to possess antioxidant properties and are derived primarily from the thermal decomposition of lignin in biomass. Phenols, alkyl aryl ethers and ketones were identified as the major constituents, while furan and pyran derivatives, sugars, acids, esters, aldehydes and alcohols were the minor constituents. Both CPAP and DCPAP also exhibited reducing power and lipid peroxide inhibitory activity (97.2% and 79%) showing that pyroligneous acid could serve as an alternative ecofriendly source of natural antioxidants.