Antibacterial and Anti-biofilm Activity of Crude Extracts of Halodule pinifolia (Hartog, 1964) against Biofilm Forming Bacterial Species
Celcia Gnana Rathinam W V *
Marine Biotoxinology Lab, CAS in Marine Biology, Faculty of Marine Sciences, Annamalai University, Parangipettai, Cuddalore - 608502, India.
Bragadeeswaran S
Marine Biotoxinology Lab, CAS in Marine Biology, Faculty of Marine Sciences, Annamalai University, Parangipettai, Cuddalore - 608502, India.
Kumaresan S
CAS in Marine Biology, Annamalai University, Cuddalore, Tamilnadu, India.
Sasidharan T
Marine Biotoxinology Lab, CAS in Marine Biology, Faculty of Marine Sciences, Annamalai University, Parangipettai, Cuddalore - 608502, India.
Sandhiya P
Marine Biotoxinology Lab, CAS in Marine Biology, Faculty of Marine Sciences, Annamalai University, Parangipettai, Cuddalore - 608502, India.
*Author to whom correspondence should be addressed.
Abstract
Marine biofouling is a serious concern in maritime activities. Since the use of TBT and heavy metal-based antifoulants was banned due to their toxic effects on non-target organisms, the hunt for eco-friendly antifoulants are still in search. Seagrasses are submerged and sessile marine angiosperms which have resistance ability against attaching epibionts. This present study focuses on the use of seagrass extracts against the marine biofouling-forming bacteria. Different colonies were isolated from the collected biofilm sample of the boat hull and were tested for their biofilm-producing ability by Congo Red agar method. The seagrass Halodule pinifolia was collected from Vellar estuary and its crude extracts such as ethanol, methanol, dichloromethane and chloroform were tested against the biofilm-forming bacteria Priestia megaterium (PQ012983), Bacillus licheniformis (PQ012984), Bacillus subtilis (PV460241), Vibrio alginolyticus (PV460242), Priestia flexa (PV460243) and Bacillus stercoris (PV460244) by well-diffusion assay. Among all the crude extracts of Halodule pinifolia the maximum zone of inhibition was exhibited by dichloromethane extracts against Bacillus stercoris (18.5±0.8mm). The overall minimum zone of inhibition was exhibited by chloroform extracts against Bacillus licheniformis (5 ± 0.6 mm). Followed by dichloromethane, methanol extract was most effective against these bacteria. Anti-biofilm activities of these effective extracts were performed using Tissue Culture Plate method, which showed the reduction in biofilm production. The dichloromethane extracts showed a greater reduction of biofilm against targeted bacterial species. The active compounds present in the effective extracts were further analysed using GS-MS. The compounds such as 2-Pentadecanon, 6,10,14-Trimethyl pentadecan and n-Hexadecanoic acid were abundantly found in the methanol and dichloromethane extracts, respectively. This study concludes that the Halodule pinifolia extracts have effective inhibiting activity against biofilm-forming microorganisms and thus can be considered as a potential source for eco-friendly marine antifoulants.
Keywords: Halodule pinifolia, anti-bacterial activity, anti-biofilm activity, biofilm-forming bacteria, GC-MS