Abstract:
Nelumbo nucifera is commonly known as “Lotus” which is highly valued in
aquatic horticulture in Sri Lanka, and broadly used in the Ayurveda and
Siddha systems of medicines. Extracts of different parts of this plant have
shown different therapeutic effects due to their phytochemical constituents.
Aqueous methanolic extracts (80%) of petals and stamens were screened
separately for in vitro antibacterial activity. Well diffusion method and Muller
Hinton Broth (MHB) dilution method in microplates were used to determine
Minimum Inhibitory Concentration (MIC) and agar plates were used to
determine Minimum Bactericidal Concentration (MBC) against two Gram positive (Staphylococcus aureus and Staphylococcus saprophyticus) and two
gram-negative bacterial strains (Escherichia coli and Pseudomonas
aeruginosa). Vancomycin and ceftriaxone were used as the positive controls
for gram positive and gram-negative microorganism, respectively and DMSO
(dimethyl sulphoxide) as negative control. Petal and stamen extracts showed
somewhat similar antibacterial activity, where the zone of inhibition (mm)
was higher for gram-negative organisms (14.3 ± 0.6) than gram-positive
organisms (11.7 ± 0.6). Methanolic extract of white lotus petals and stamens
showed comparatively good antibacterial activity against all four organisms.
Results emphasized that lotus flower extracts have the potential to be used as
antibacterial agent and the importance of the use of natural products to treat
pathological conditions.
