Gas Chromatography-Mass Spectrometric analysis and antioxidant property of leaf extracts of <i>Chamaecrista rotundifolia</i>

Abstract

Chamaerista rotundifolia is a medicinal plant whose leaves are useful for the treatment of many diseases including cancer, diarrohea and pain. This plant is underexploited in the area of extraction and bioassays that will establish its efficacy. The aim of the present study is to determine the antibacterial and antioxidant properties as well as to analyze the chemical compositions of the extracts from the plant leaves through the use of Gas chromatography – Mass Spectrometry (GC- MS) technique. The antibacterial activity of n-hexane, chloroform, ethyl acetate, and methanol extracts of the plant was tested against six (6) strains of bacteria named Pseudominas aeruginosa, Staphylococcus aerus, Klebsiella pneumoniae, Acinetobacter baumannii, Enterococcus faecalis, and Escherichia coli. The extracts of the plant exhibited no significant antibacterial property on the tested organisms. The result of antioxidant activity (using 1,1-diphenyl-2-picryl hydrazy (DPPH) radical scavenging) revealed that Chamaecrista rotundifolia ethyl acetate extract has low antioxidant properties due to its high (>1164.878), and negative (< 0) Inhibition Concentration at 50% values for antioxidant. However, the methanol extract exhibited antioxidant activity with an IC₅₀ value of 5 μg/mL, which is comparable to that of ascorbic acid, 2.55 μg/mL. The GC-MS results of this extract showed that it contains some bioactive compounds. Meanwhile, the ethyl acetate extract of the plant contains 75 chemical compounds, 4 of which are principal constituents, 6 are minor and others are trace. The chloroform extract of C. rotundifolia leaf was, however, inactive in inhibiting the growth of the bacteria as the extract also had a high inhibition value when compared with the inhibition concentration at 50%, which shows its low level of antioxidant activity. Our results of antibacterial activity were found not promising while the antioxidant activity on its own showed an interesting result that could be useful in the prevention of oxidative stress side effects and cancer related diseases.