Introduction: Rhizophora mucronata is a plant of marine origin commonly referred to as asiatic mangrove, red mangrove or
loop root mangrove . R. mucronata species are utilized traditionally for treating various health conditions like haematoma,
hepatitis, hematuria, ulcers, elephantiasis and so on.
Aim: This study aims at evaluating the antibacterial activity of Rhizophora mucronata mangrove leaf extract against the
antibiotic resistant pathogens.
Materials and Methods: The fresh leaves of Rhizophora mucronata were collected, washed, shade dried for 2-3weeks
and turned into a fine powder. For extract preparation, 10g of powdered sample mixed with 100 ml methanol for 24 hours
and passed through Whatman filter paper. It was centrifuged at 3000 rpm and further filtered by 0.45 µm syringe micro
filter and evaporated via rotary evaporator. Drug resistant Staphylococcus aureus, Klebsiella pneumoniae and
Pseudomonas aeruginosa collected were cultured in Muller Hinton broth for 24 hours to prepare the bacterial suspension.
The concentration of microbial suspension was fixed at 108 CFU/ml. 1ml of suspension was spread over on Muller Hinton agar
plate and incubated for 24hrs at ambient temperature. Whatman filter paper discs (5mm) were impregnated with various
concentrations (50, 100, 150, 200, 250 & 300 µg/ml) of leaf extract , inhibition zones around the discs were measured.
The MIC of the leaf extract was determined in 5 concentrations (10 μg/ml, 20 μg/ml, 30 μg/ml, 40 μg/ml and 50 μg/ml)
inoculated bacteria in test tubes are incubated for 24 hr and the results are noted as well growth (+) and inhibited (-).
Results: Comparing the zone of inhibition measured against the three bacteria, Rhizophora mucronata leaf extract showed
the maximum zone of inhibition,32 ± 1.24 mm, at the maximum concentration (300 μg/ml) against Pseudomonas
aeruginosa and Klebsiella pneumoniae Staphylococcus aureus showed a maximum inhibition of 27± 1.22 and 23 ± 1.32
respectively.The Minimum Inhibitory Concentration (MIC) produced by Staphylococcus aureus, Klebsiella pneumoniae and
Pseudomonas aeruginosa was found out to be 40 μg/ml, 30 μg/ml and 30 μg/ml respectively.
Conclusion: This study presented extensive information about the antibacterial activity of Rhizophora mucronata against
antibiotic resistant pathogens. Infection with drug resistant microorganisms such as Staphylococcus aureus, Klebsiella
pneumoniae and Pseudomonas aeruginosa may be treated with Rhizophora mucronata after further studies
Key words: Antibacterial activity,Antibiotic resistance Mangrove plant, Natural source, Rhizophora mucronate