2 April - June 2015
Antioxidant and Antibacterial Activities of Indian Marsh
Fleabane (Pluchea indica (L.) Less)
Rawinipa Srimoon* and Suchanya Ngiewthaisong
Department of Applied Science and Biotechnology, Faculty of Agro-Industrial Technology, Rajamangala
University of Technology Tawan-OK, Chanthaburi Campus, Chanthaburi, Thailand.22210.
*Corresponding author: firstname.lastname@example.org
Ethanolic extracts of various parts of Pluchea indica (L.) Less were analyzed for
DPPH radical scavenging capacities, total phenolic contents and antibacterial activities.
The results showed that fresh root extract had the most antioxidant activities (0.16?0.001
mg/mL EC50, 20.02?0.177 mg/g TEAC and 15.79?0.008 mg GAE/g total phenolic content).
Antioxidative activities of most fresh samples were signifiantly higher than that of dry
samples (P<0.05). The low antioxidative activities of dry samples might be due
to the effect of drying (60oC for 2 days). In contrast, tea leaves extract exhibited the
high antioxidant capacities (0.28?0.012 mg/mL EC50, 11.86?0.519 mg/g TEAC and
3.18?0.012 mg GAE/g total phenolic content) due to the formation of Maillard reaction
products during heating at lower temperature for a shorter period (50oC for 2 hrs).
Antibacterial activities assessed by the disc diffusion method showed that all of
investigated bacteria were inhibited by the extract of fresh root, fresh twig, dry stem and
tea leaves, while the extract of fresh and dry flwer, fresh and dry leaves, and dry root
showed the less inhibition potential. The minimal inhibitory concentrations (MICs) of
extracts using agar microdilution and disc diffusion method showed signifiant inhibition
activities even at 2-16 fold dilutions, with the most effective result in fresh root extract as
low as 64 fold dilution. Tea leaves extract also had high inhibitory capacities when the
concentrations were 4-16 fold dilution. Fresh root extract had the most excellent inhibition
potential against Bacillus cereus, Pseudomonas florescens and Salmonella typhimurium
(0.16, 0.16 and 0.32 mg/mL MICs, respectively). Inhibitory activities against Escherichia
coli were very low. The increase in antioxidant activities did increase antibacterial abilities.
Keywords: Pluchea indica (L.) Less, Antioxidant, Antibacterial activities