Synergistic Efficacy of Phytochemical, Antioxidant and Bactericidal Properties of the Aerial Essential Oil of Laggera crispata

Abstract

This study was undertaken to provide more scientific information about the phytochemical composition of Laggera crispata known for its medicinal uses. Essential oil was isolated by hydro-distillation, analysed using GC-MS, UV-Visible Spectrophotometer and other established biochemical assays were used for the study. The GC-MS analysis of the aerial essential oil of L. crispata showed the presence of 35 medicinal organic compounds making up 84.4% of the oil. The most abundant component was a phenolic compound called 2-tert-Butyl-1,4-dimethoxybenzene (54.5%). The other major terpenoids present in the oil were α-humulene (6.9%) and (+)-sabinene (5.9%). The TPC, TFC, TAA and TAC values of the aerial essential oil of L. crispata were 172.75±0.00 μgmg-1 GAE, 48.69±0.00 μgmg-1 QE, 61.85±0.00 μgmg-1 AAE and 726.92±0.00 μgmg-1 AAE respectively. DPPH IC50 and AAI values of the essential oil were 1.5 μgml-1 and 26.7. The essential oil displayed varying inhibitory activities against Gram-positive and Gram-negative bacteria with zones of inhibition ranging from 08-30 mm. The in vitro pharmacological activities added scientific support to the use of L. crispata in alternative and complementary medicine. The essential oil of L. crispata grown in Nigeria will play beneficial roles in human and animal health and therefore a research on this plant might be of great value in drug industries. Key words: Laggera crispata, Asteraceae, Aerial essential oil, Secondary metabolites, Antioxidant, Antibacterial.