Browsing by Author "Lokuwalpola, D. V."

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Antibacterial activity of Flueggea leucopyrus Willd
(Faculty of Science, University of Kelaniya, Sri Lanka, 2021) Karunarathne, E. D. C.; Lokuwalpola, D. V.; Sandaruwan, K. P. A. M.; Dabarera, M. D.; Wanigasekara, D. N.
Fluggea leucopyrus Willd. (Euphorbiacea) known as ‘Katupila’ in local dialect is a plant widely used in indigenous medicinal system in Sri Lanka as a remedy for cancers and infectious diseases. Sufficient scientific investigations however are unavailable to rationalize the ethnobotanical and ethnopharmacological significance of the plant. Present study was conducted to investigate the antimicrobial potential of F. leucopyrus whole plant extract. The antimicrobial activity of the methanolic extract of F. leucopyrus was determined by agar well diffusion method. The extract was tested against five standard bacterial strains and eight clinically isolated bacterial cultures; Staphylococcus aureus (ATCC 25923), Staphylococcus aureus (ATCC 6538), Escherichiacoli (ATCC 8739), Pseudomonas aeruginosa (ATCC 9027), Pseudomonas aeruginosa (ATCC 27853), Streptococcus pyogenes, Klebsiella pneumoniae, Proteus mirabilis, Enterococcus faecalis, Salmonella typhi, Bacillus subtilis, Methicillin Resistant Staphylococcus aureus (MRSA) and Staphylococcus saprophyticus. The test was triplicated for each microorganism. Ciprofloxacin was used as the positive control while 20% Dimethyl sulfoxide (DMSO) which was used to dissolve the plant extract was used as the negative control. No inhibition of growth was observed in the negative controls and the positive control was able to inhibit the growth of all test bacterial strains used. The growth of S. pyogenes, K. pneumoniae, S. typhi, B. subtilis, E.coli (ATCC 8739) was not affected by F. leucopyrus extract, meanwhile S. aureus (ATCC 25923), S. aureus (ATCC 6538), P. mirabilis, E. faecalis, MRSA, P. aeruginosa (ATCC 9027), P. aeruginosa (ATCC 27853) and S. saprophyticus seemed to be susceptible to the extract showing inhibition zone diameters of 12.67±0.58 mm, 12.67±0.58 mm, 15.33±0.58 mm, 9.67±0.58 mm, 13.67±0.58 mm, 12.67±0.58 mm, 11.33±0.58 mm and 13.67±0.58 mm respectively. These preliminary observations suggest that F. leucopyrus plant is a potent source of antimicrobial substances. Further studies are required to determine the phytochemicals responsible for the antimicrobial action.
General hygienic condition of packaged lettuce samples purchased from selected supermarkets in Gampaha district, Sri Lanka
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Lokuwalpola, D. V.; Wanigasekara, D. N.; Sudesh, A. D. H.; Karunarathne, E. D. C.
Lettuce (Lactuca sativa) is usually consumed in raw form or processed minimally. Therefore, consumption of contaminated raw lettuce is associated with food outbreaks due to poor hygienic condition. Lettuce leaves can be contaminated with pathogenic microorganisms during harvesting, packaging and transportation processes. This study focuses on the general hygienic condition of the packaged lettuce available in supermarkets. Ten packaged samples were purchased from ten supermarkets of Gampaha district, Sri Lanka and they were labeled as L1, L2, L3, L4 and so on. 10 g of each lettuce sample was weighed and transferred to stomacher bags containing 90 mL of sterilized peptone water aseptically. After homogenization, a dilution series was prepared for each sample up to 10-6. One-milliliter aliquot of dilutions from 10-2 to 10-6 of each sample was plated using pour plate method. The used agar medium was Plate Count Agar. The inoculated agar plates were incubated at 30°C for 24 hours. Duplicates were used for all the plated dilutions of each sample. Average Colony Forming Units per gram (CFUg-1) was calculated. The calculated CFU/g values of L1 to L10 were 2.1×106, 1.8×106, 2.8×106, 2.3×105, 2.0×106, 1.2×105, 2.5×105, 1.9×104, 1.3×105 and 2.2×106 respectively. The highest obtained CFU per gram of lettuce was for L3. The lowest value was given by sample L8. Very high microbial load in packaged lettuce samples may indicate the poor hygienic condition