GC-MS, Antimicrobial and In vitro Antioxidant Assay of the Leaf Extract of Alternanthera dentata

Aims: To evaluate the phytochemical content, antimicrobial and antioxidant activity of the leaf extract of Alternanthera dentata.

Study Design: Ethanol was used to extract the plant material for GC-MS analysis and antimicrobial studies while methanol extract was used for the antioxidant study.

Place and Duration of Study: Department of Chemistry, Alvan Ikoku Federal College of Education, Owerri and Department of Veterinary Medicine, Michael Okpara University of Agriculture, Umudike, between July 2013 and December 2013.

Methodology: Dried leaves of Alternanthera dentata were extracted in ethanol for 48 hours and concentrated under reduced pressure. Five microbial isolates were used to test the susceptibility of the extract. DPPH and FRAP assays were used to test the antioxidant capacity of the plant.

Results: Eleven phyto–constituents were identified from the leaves. The most abundant compound was hexadecanoic acid (31.60%), followed by phytol (24.61%), and octadecanoic acid (10.56%). Other compounds identified in the leaves were glycerin (5.83%), levoglucosan (2.49%), alpha-D-glucopyranoside (5.21%), tetradecanoic acid (1.27%), 1-octadecyne (2.47%), octadecanoic acid, ethyl ester (6.79%), 10-undeceyn-1-ol (6.67%) and hexadecanoic acid (2.51%). The extract showed low antioxidant activity compared to ciprofloxacin, used as standard while antioxidant activity of the extract was lower than that of ascorbic acid used as the standard. At a concentration of 400 mg/ml, the extract produced the optimum activity using FRAP assay.

Conclusion: This study has revealed that A. dentata is rich in many important phytochemicals which could be further isolated and characterized for drug production.