Evaluation of Antibacterial Activity of Zobo and Bay Leaf Extracts on Enteropathogenic Bacteria

Main Article Content

S. A. Wemedo
N. P. Akani
A. D. Amadiali


Aim: The antibacterial activity of Bay leaf (Laurus nobilis L.) and Zobo leaf (Hibiscus sabdariffa L.) extracts on enteropathogenic bacteria was investigated.

Study Design: The study utilized well in agar diffusion to investigate the antimicrobial properties of the extracts.

Place and Duration of Study: Department of Microbiology, Rivers State University and the study was carried out in August, 2018 to October, 2018.

Methodology: Faecal samples were collected from a medical laboratory and inoculated on eosin methylene blue and mannitol salt agar plates for Escherichia coli and Staphylococcus aureus using standard microbiological techniques. The bacterial isolates were subjected to biochemical and molecular (PCR) identification so as to ascertain the distinctiveness of the isolates. Hot water and absolute alcohol were used as the extracting solvents. Concentrations of the extracted solvents was tested against E. coli and S. aureus using the well in agar method.

Results: The result showed that both hot aqueous and alcoholic extracts of Bay leaf showed no sensitivity against the tested bacteria, whereas the extracts of hot dry aqueous and alcohol of Zobo leaf showed remarkable zones of inhibition against the tested bacteria. The zones of inhibition in the dry hot aqueous extract of zobo leaf with concentrations of 0.25 µg/mL, 0.125 µg/mL and 0.063 µg/mL were 31.3±0.1, 25.6±1.2 and 10.0±0.0, respectively. The minimal inhibitory concentration of the dry hot aqueous of zobo extract was observed at 0.063 µg/mL for E. coli, while zones of inhibition of 33.3±0.0, 30.1±0.3, 17.2±1.0 and 15.0±0.1 mm were recorded from the dry alcoholic extract of zobo leaf on E. coli given similar concentrations and the MIC was observed at the 0.031 µg/mL concentration. The result also showed that out of the four concentrations of the dry hot aqueous extract, only the 0.25 µg/mL concentration was able to show 14.2±0.0 mm inhibition on S. aureus, while the concentrations of 0.25 µg/ml and 0.125 µg/mL were the only two concentrations of the dry alcohol that showed levels of sensitivity with zone diameters of 29.3±1.0 and 25.2±0.0, respectively.

Conclusion: The plant extracts of zobo leaves which displayed remarkable activity at fairly-low concentrations could be recommended for use against similar bacteria. Thus, investigation and adoption of plant extracts in modern medicine should be encouraged as this may be the break through needed to combat the ever-increasing resistance to commonly used antibiotics.

Antimicrobial properties, Laurus nobilis, Hibiscus sabdariffa, enteropathogenic bacteria

Article Details

How to Cite
Wemedo, S. A., Akani, N. P., & Amadiali, A. D. (2019). Evaluation of Antibacterial Activity of Zobo and Bay Leaf Extracts on Enteropathogenic Bacteria. Journal of Advances in Microbiology, 16(2), 1-7. https://doi.org/10.9734/jamb/2019/v16i230118
Original Research Article


Sanjoy P, Yogeshwer S. Herbal medicine: Current status and the future. Asian Pacific Journal of Cancer Prevention. 2002;4(4): 281-288.

Ekor M. The growing use of herbal medicines: Issues relating to adverse reactions and challenges in monitoring safety. Frontiers in Pharmacology. 2014;4: 177.

Tilburt JC, Kaptchuk TJ. Herbal medicine research and global health: An ethical analysis. Pubmed, World Health Organization. 2008;24(8):594-599.

Amegbor PM. Health-seeking behavior in Asikuma-Odoben-Brakwa District: A pluralistic health perspective. 2014,1:1-2.

Erci B. Medical herbalism and frequency of use: A compendium of essays on alternative therapy. 2012;195.

Webb D. Phytochemicals’ role in good health: Today’s dietician. 2013;15(9):70.

Liu RH. Health benefits of fruits and vegetables are from additive and synergistic combinations of phyto-chemicals. American Journal of Clinical Nutrition. 2003;78(3):517-520.

Ugbogu AE, Akubugwo EI, Iweala EJ, Uhegbu FO, Chinyere GC, Obasi NA. Role of phytochemicals in chemoprevention of cancer: A review. International Journal of Pharmaceutical and Chemical Sciences. 2013;2(2):567-575.

Zeb A, Sadiq A, Ullah F, Ahmad S, Ayaz M. Phytochemical and toxicological investigations of crude methanolic extracts, subsequent fractions and crude saponins of Isodon rugosus. Journal of Biological Research. 2014;47(57):1-6.

Selvamohan T, Ramadas S, Kishore SK. Antimicrobial activity of selected medicinal plants against some selected human pathogenic bacteria. Advances in Applied Science Research. 2012;3(5):3374-3381.

Pan S, Zhou S, Gao S, Yu Z, Zhang S, Tang M, Sun J, Ma D, Han Y, Fong W, Ko K. New perspectives on how to discover drugs from herbal medicines: CAM’s outstanding contribution to modern therapeutics. Journal of Evidence-Based Complementary and Alternative Medicine. 2013;1:1.

Cowan MM. Plant products as antimicrobial agents. Journal of the American Society for Microbiology, Clinical Microbiology Reviews. 1999;12(4):564-582.

Ventola CL. The antibiotic resistance crisis: Causes and threats. Journal of Pharmacy and Therapeutics. 2015;40(4):277-283.

Nester MT, Nester EW, Roberts CE, Pearsall NN, Anderson DG. Microbiology- A human perspective. New York: WCB/McGraw-Hill Book Company; 1998.

Obire O, Ogbonna S. Antimicrobial activity of some seed extracts on bacteria and fungi isolated from maize slurry in Port-Harcourt metropolis. In: Press; 2017.

Cheesbrough M. Microbiological test: District laboratory practice in tropical countries. 2000;1-226.

Chahal KK, Kaur M, Bhardwaj U, Singla N, Kaur A. A review on chemistry and biological activities of Laurus nobilis L. essential oil. Journal of Pharmacognosy and Phytochemistry. 2017;6(4):1153-1161.

Kota CS, Paladi S. Evaluation of antibacterial activity of Syzygium aromaticum, Laurus nobilis and Cuminum cyminum extracts and their combination. International Journal of Pharmaceutical Sciences and Research. 2013;4(12):4745-4748.

Malti JE, Amarouch H. Antibacterial effect, histological impact and oxidative stress studies from Laurus nobilis extract. Journal of Food Quality. 2009;32:190-208.

Millezi FA, Caixeta DS, Rossoni DF, Cardoso M, Piccoli RH. In vitro antimicrobial properties of plant essential oils Thymus vulgaris, Cymbopogon citratus and Laurus nobilis against five important foodborne pathogens. Journal of Food Science and Technology. 2010;15(5): 3378-3383.

Sedef NE, Karagozlu N, Karakaya S, Sahin S. Antioxidant and antimicrobial activities of essential oils extracted from Laurus nobilis L. leaves by using solvent-free microwave and hydrodistillation. Journal of Food and Nutrition Sciences. 2014;5(1):97-106.

Salem MZ, Olivares-Perez J, Salem AZ. Studies on biological activities and phytochemical composition of Hibiscus species- A review. Life Science Journal. 2014;11(5):1-8.

Saeidi S, Bokaeian M, Shiekh M, Shahi Z. Antimicrobial activity of Hibiscus sabdariffa extract against human pathogen. International Journal of Advanced Biological and Biomedical Research. 2014;2(2):433-439.

Panaitescu M, Lengyel E. Monitoring the antibacterial activity of Hibiscus sabdariffa extracts. Journal of the Management of Sustainable Development, Sibiu, Romania. 2017;9(1):31-40.

Nwaiwu NE, Mshelia F, Raufu IA. Antimicrobial activities of crude extracts of Moringa oleifera, Hibiscus sabdariffa and Hibiscus esculentus seeds against some enterobacteria. Journal of Applied Phyto-technology in Environmental Sanitation. 2012;1(1):11-16.

Jantrapanukorn B, Pongpraritt S, Powthong P, Pheungphu T. The study of antibacterial activity in enteric pathogens of roselle (Hibiscus sabdariffa Linn.) by Broth micro-dilution method. Journal of Applied Pharmaceutical Sciences. 2017;7(5):119-122.

Al-Hashimi AG, Mahmood SA. The nutritional value and antioxidant activity of bay leaves (Laurus nobilis L.). Basrah Journal of Veterinary Research. 2016; 15(2):246-260.

Higginbotham LN, Burris KP, Zivanovic S, Davidson MP, Stewart NC. Antimicrobial activity of Hibiscus sabdariffa aqueous extracts against Escherichia coli O157:H7 and Staphylococcus aureus in a microbiological medium and milk of various fat concentrations. Journal of Food Protection. 2014;77(2):262-268.

Sekar M, Hashim HN, Fadzil FS, Sukaini SS, Zukhi NN, Nadzri MN, Abdullah MS. Antibacterial activity of the methanolic extract of Hibiscus sabdariffa leaves and fruits. British Microbiology Research Journal. 2015;5:1-6.

Sulaiman FA, Kazeem MO, Waheed MA, Temowo SO, Azeez IO, Zubair FI, Adeyemi TA, Nyang A, Adeyemi SO. Antimicrobial and toxic potential of aqueous extracts of Allium sativum, Hibiscus sabdariffa and Zingiber officinale in wistar rats. Journal of Taibah University for Science. 2014;8(1):315-322.

Garbi MI, Saleh M, Badri AM, Ibrahim TI, Mohammed SF, Alhassan MS, Elshikh AA, Kabbashi AS. Antibacterial activity, phytochemical screening and cytotoxicity of Hibiscus sabdariffa (calyx). Journal of Advancement in Medicinal Plant Research. 2016;4(4):116-121.