Abstract:
Background: Cinnamomum cassia (Davul kurundu) is a commonly used plant in Ayurvedic
medicine in Sri Lanka, for the treatment of many diseases. However, the therapeutic potential for
treating bacterial and fungal infections has not been scientifically proven.
Objective: To determine the antibacterial activity of the methanol extracts of Cinnamomum cassia
leaves and bark against pathogenic Staphylococcus aureus (ATCC25923)
Methods: Agar well diffusion assay was used in the study against S. aureus. The selected plant
was authenticated from the Botany Division, Bandaranayake Memorial Ayurvedic Research
Institute, Nawinna, Maharagama (Acc No 4602). Plant extractions were prepared by using
methanol in maceration method into the 1:3 ratio. Each extract's mean zone of inhibition (ZOI)
was determined after incubating the agar plates for 24 hours at 37 0C. The potency of each extract
was validated against positive control gentamicin (10µg/mL) and negative control dimethyl
sulfoxide (50%). Then Minimum Inhibitory concentration (MIC) was determined by macro broth
dilution method and Minimum Bactericidal concentration (MBC) was determined by subculturing
on blood agar.
Results: The mean(±SD) ZOI of the concentrations 500mg/mL, 250mg/mL, and 125mg/mL of C.
cassia bark extract were measured as 24.15(±0.15) mm, 20.5(±0.20) mm, 18.35(±0.35) mm,
respectively. The mean ZOI with the concentrations of 500mg/mL, 250mg/mL, and 125mg/mL of
C. cassia leaf extract were measured as 21.5(±0.50) mm, 18.15(±0.15) mm, 16.35(±0.35) mm,
respectively. Mean ZOI of the positive control was 29.01(±1.18) mm. MIC values of C. cassia
bark extract and C. cassia leaf extract were 7.81mg/mL and 62.5mg/mL. MBC values of C. cassia
bark extract and C. cassia leaf extract were 15.63mg/mL and 125mg/mL.
Conclusions: The study showed that the methanol extracts of C. cassia leaves and bark can be
used to treat S. aureus infections. Out of the two extracts, C. cassia bark extract showed the
highest ZOI and lowest MIC and MBC values. Therefore C. cassia bark extract can be
recommended as an effective antibacterial agent against S. aureus
