Abstract:
Plants are a natural source of novel antimicrobials. Fifty percent of new drugs are
derived from plants, as plants contain phytochemicals that have antimicrobial activity.
As many plants have not yet been investigated for antimicrobial activity, it is a good
source for discovering novel antibiotics. In Ayurveda practices, plants are used in the
treatment of wounds and infections. Punica granatum (Delum) has been used in herbal
medicine for ages. However, the medical benefits of these plants have been discussed in
only a few publications. The plant is documented to possess beneficial effects for eye
infections, heart diseases, dysentery, coughs, oedema, worms’ diseases, asthma, skin
diseases, fever, etc. This study aimed to evaluate the antimicrobial activity of aqueous
extracts of the leaves and bark of the Punica granatum plant against Staphylococcus
aureus and Pseudomonas aeruginosa. Staphylococcus aureus and Pseudomonas
aeruginosa were obtained from the biomedical laboratory of Kaatsu International
University. Plant materials were collected from the Colombo district, and authentication
has been obtained from the botany division of the Bandaranayake Memorial Ayurvedic
Research Institute, Nawinna, Maharagama, Sri Lanka. Extractions of plants were
obtained by the decoction method, and a series of concentrations were prepared. The
antibacterial activity of the extracts of the leaves and bark of delum against
Staphylococcus aureus (ATCC 25923) and Pseudomonas aeruginosa (ATCC 27853)
was measured using the agar-well diffusion method. Gentamicin (10 μg/ml) was used
as the positive control. Each assay was done in triplicate. Aqueous extract of leaves
showed the highest antimicrobial activity with inhibition zones of 28.00 ±1.00 mm
(Staphylococcus aureus) and 21.0 and 0±1.00 mm (Pseudomonas aeruginosa), while
bark extract (aqueous) showed 22.33±0.58 mm and 17.67±0.58mm of inhibition zones
against Staphylococcus aureus and Pseudomonas aeruginosa, respectively. Both
Punica granatum leaf and bark aqueous extracts possess antibacterial properties.
Following testing on various clinical isolates, the extracts demonstrate potential for the
development of antibacterial formulations targeting Staphylococcus aureus and
Pseudomonas aeruginosa.
