Chemical Composition and Antibacterial Activity of Extracts of Cymbopogon Citratus (Lemon Grass) and Phyllantus Amarus (Stone Breaker) Leaves

Abstract

This study described the chemical composition, antioxidant and antibacterial activities of the ethanol and aqueous extracts of fresh and dried leaves of Phyllantus amarus (PA) (Stone breaker), Cymbopogon citratus (CC) (Lemon grass) and combination of stone breaker and lemon grass (PA/CC and DL/DP) using standard methods. The proximate and mineral results showed that both fresh and dried samples of Phyllantus amarus and Cymbopogon citratus were rich in crude fibre (18.53%, 14.65%), ash (16.27%, 2.29%), potassium (95.56 mg/100g, 54.04 mg/100g), calcium (58.57 mg/100g, 7.05 mg/100g), and sodium (15.23 mg/100g, 9.84 mg/100g) respectively. The ability of the extracts to scavenge 2, 2 diphenyl -2- picryl-hydrazyl (DPPH) radical showed that the fresh PA had the highest scavenging activity of 91.12 mg/g, followed (PA/CC) 90.93 mg/g and dried PA (85.61mg/g). The phytochemical composition of the extracts also revealed that they contain high content of cardiac glycoside (11.62 mg/g - 64.81 mg/g), terpenoid (14.56 mg/g - 69.66 mg/g), phenol (14.73 mg/g - 53.93 mg/g), saponin (22.61 mg/g - 30.47mg/g). Dried lemon and dried Phyllantus amarus (DL/DP) was found to be rich in Vitamin A (22.22 mg/g), while the lowest value of Vitamin E (0.36 mg/g) was obtained from fresh lemon grass (0.36mg/g). Antibacterial assay carried out on the two leaves extracts showed that they produced mild antibacterial activity against some foodborne pathogen (Bacillus cereus, Shigella dysenteriae, Escherichia coli, Salmonella spp, Staphylococcus aureus, Pseudomonas spp). with zones of inhibition of 4.3 mm -9.1mm. Further studies should be carried out to investigate the employment of the leaves in production of functional food