1.Antibacterial and antibiotic potentiating capabilities of extracts isolated from Burkillanthus malaccensis, Diospyros hasseltii and Cleisthanthus bracteosus against human pathogenic bacteria
Kathirvalu, G. ; Chandramathi, S. ; Azahar, S.A. ; Atiya, N. ; Begum, S. ; Christophe, W. ; Sulaiman, M. ; Abdullah, N. ; Mani, R.R. ; Jindal, H.M. ; Zulkipli, M.
Tropical Biomedicine 2023;40(No.2):152-159
Antibiotics which once a boon in medicine and saved millions of lives are now facing an ever-growing
menace of antibacterial resistance, which desperately needs new antibacterial drugs which are innovative
in chemistry and mode of action. For many years, the world has turned to natural plants with antibacterial
properties to combat antibiotic resistance. On that basis, we aimed to identify plants with antibacterial
and antibiotic potentiating properties. Seventeen different extracts of 3 plants namely Burkillanthus
malaccensis, Diospyros hasseltii and Cleisthanthus bracteosus were tested against multi-drug resistant
Acinetobacter baumannii, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Methicillinresistant Staphylococcus aureus (MRSA) and methicillin-susceptible Staphylococcus aureus (MSSA).
Antibacterial activity of hexane, methanol and chloroform extracts of bark, seed, fruit, flesh and leaves
from these plants were tested using, disk diffusion assay, minimum inhibitory concentration (MIC) and
minimum bactericidal concentration (MBC) assays. Antibiotic potentiating capabilities were tested using
time-kill assay. B. malaccensis fruit chloroform extract showed the biggest zone of inhibition against MRSA
(13.00±0.0 mm) but C. bracteosus bark methanol extract showed the biggest inhibition zone against
MSSA (15.33±0.6 mm). Interestingly, bark methanol extract of C. bracteosus was active against MRSA
(8.7±0.6 mm), MSSA (7.7±0.6 mm) (Gram-positive) and A. baumannii (7.7±0.6 mm) (Gram-negative).
Overall, the leaf methanol and bark methanol extract of C. bracteosus warrants further investigation
such as compound isolation and mechanism of action for validating its therapeutic use as antibiotic
potentiator importantly against MRSA and A. baumannii.