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Antimicrobial Activity of Ethanolic Extracts of Ocimum basilicum leaf from Saudi Arabia



Amjad Khalil
 
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ABSTRACT

Essential oils or volatile oils from medicinal plants have potentially very strong antimicrobial activities for control of pathogenic microorganisms. Ocimum basilicum is one of the medicinal plants which are widely used as sources of extracts with strong antibacterial and antioxidant properties. In this study, the leaf extract of Ocimum basilicum was tested for its antibacterial activity against some human pathogenic bacteria (Staphylococcus aureus and Escherichia coli). Antimicrobial activity test was carried out by using the hole-plate diffusion method. Plant materials were dried and extracted with 95% ethanol. The tested extract showed very strong antimicrobial activity against both strains. The antimicrobial activity was evaluated by measuring the zone of inhibition. The strongest inhibition activity was observed against E. coli (21 mm zone) at 200 mg mL-1 of leaf extract followed by Staphylococcus aureus which showed 16 mm inhibition zone at 200 mg mL-1 of leaf extract. Physical properties of the extract of Ocimum basilicum were evaluated. The color of the extract is greenish, has intense scent, density is 0.937 g cm-3 at 25°C, refractive index is 1.489 and specific gravity is 0.887.

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  How to cite this article:

Amjad Khalil , 2013. Antimicrobial Activity of Ethanolic Extracts of Ocimum basilicum leaf from Saudi Arabia. Biotechnology, 12: 61-64.

DOI: 10.3923/biotech.2013.61.64

URL: https://scialert.net/abstract/?doi=biotech.2013.61.64
 
Received: November 02, 2012; Accepted: January 16, 2013; Published: July 01, 2013



INTRODUCTION

Ocimum basilicum or Al-Rehan (in Arabic) is a well-known medicinal plant which has received a great deal of attention over the past few decades around the world. It belongs to the Lamiaceae family of floral plants usually producing white-purple flowers (Daneshian et al., 2009). Extracts of Ocimum basilicum having strong antibacterial and antioxidant properties are widely used for medicinal purposes. Plant parts and essential oils from Ocimum plants are used as spices and flavors for many food products and effective drugs in folk medicine (Sacchetti et al., 2004; Jirovetz et al., 2003).

Many medicinal plants which produce antioxidants, antibacterial, antiviral and fungicidal agents have gained popularity in recent years. Extracts from Ocimum basilicum have shown strong inhibitory effects on HIV-1 reverse transcriptase and platelets aggregation (Yamasaki et al., 1998; Okazaki et al., 1998). These extracts are also a rich source of flavor compounds and volatile oils which possess compounds that contain antimicrobial activities (Yamasaki et al., 1998; Wannissorn et al., 2005). Some parts of sweet basil such as leaves and flowers are used as carminative, galactogogue, stomachic and antispasmodic medicinal plants in folk medicine (Marwat et al., 2011).

Due to random and wide usage of antibiotics in the treatment of infectious diseases, a multiple drug resistance against pathogenic microorganisms has been developed in recent years (Davies, 1994; Service, 1995). One of the best ways to solve this problem, is to look for new therapeutic agents from plants which contain antimicrobial activities against these pathogenic microorganisms (Kalemba and Kunicka, 2003; Faleiro et al., 2003).

Khaki et al. (2011) investigated the role of O. basilicum extracts as a source of natural antioxidants to assist the sperm parameters in rats. The results of their work showed that O. basilicum extracts significantly affect the process of spermatogenesis and might be a promising treatment for enhancing healthy sperm parameters in rats.

The purpose of this study was to evaluate the Saudi Ocimum basilicum leaf extract as antimicrobial agents against some human pathogens.

MATERIALS AND METHODS

Ocimum basilicum were cultivated and collected at the flowering stage from a home garden in the Eastern Province of Saudi Arabia. In this study, extracts from the leafs of Ocimum basilicum were tested for their antimicrobial activities.

Preparation of extracts: Plant materials were dried in shade at room temperature and ground by using a blender. Two hundred and fifty gram of plant powder was soaked in 1.25-1.5 L of 95% ethanol for 5 days at room temperature. The mixture was mixed daily for regular infusion. After a five-day period, the extract was filtered by using Whatman filter paper No. 1. The filtrate was dried by using a rotary evaporator at 60°C. The dried extract was stored in sterile glass bottles at -20°C until use (Kandil et al., 1994).

Microorganisms: Two bacterial species, gram-positive Staphylococcus aureus and Gram-negative E. coli were used. These microorganisms were obtained from KFUPM clinic. We also tested E. coli-ATCC 25922 and Staphylococcus aureus-ATCC 33591 as standard strains.

Screening of antimicrobial activities: Inoculums containing 106 bacterial cells mL-1 were spread on nutrient agar medium. Antimicrobial activity test was carried out by using the hole-plate diffusion method (Khalil et al., 2009). Holes were made on the media by using 8 mm cork borer. The dried plant extracts were dissolved in dimethylsulfoxide (DMSO) to a final extract amount of 200, 150, 100 and 50 mg mL-1. Each hole (diameter 8 mm) was filled with 50 μL of plant extract. The inoculated agar plates were incubated at 37°C for 24 h. After the incubation period, the diameter of inhibition zone to each hole was measured in mm (the inhibition zone is an average of 3 experiments). The inhibition zone is the area surrounding the hole and there is no growth of the inoculated microorganism. Negative controls of DMSO and 96% ethanol showed no antimicrobial activity against any of the tested microorganisms.

Negative controls were prepared using the same solvents employed to dissolve the plant extracts. Penicillin-G (10 μg disk-1) was used as a positive reference standard to determine the sensitivity of one strain from each bacterial species. Antimicrobial activity was evaluated by measuring the zone of inhibition against the test organisms. Each assay in this experiment was repeated twice.

RESULTS AND DISCUSSION

The antimicrobial activity of ethanol leaf extracts of Ocimum basilicum from Saudi Arabia was investigated against some human pathogenic bacteria (Staphylococcus aureus and Escherichia coli). The strongest inhibition activity of the leaf extract was observed against E. coli followed by Staphylococcus aureus. Physical properties of the extract were investigated.

Physical properties: Table 1 summarizes the physical properties of the Ocimum basilicum extract; the colour of the extract is greenish, has intense scent, density is 0.937 g cm-3 at 25°C, refractive index is 1.489 and specific gravity is 0.887. These physical properties are in agreement with the physical properties reported in a previous study done by Hanif et al. (2011).

Antimicrobial activity: The antimicrobial activity of Ocimum basilicum leaf extract was tested against 2 pathogenic bacteria (Staphylococcus aureus and E. coli) shown in Table 2. The tested extract showed very strong antimicrobial activity against these 2 pathogenic bacteria. The antimicrobial activity was evaluated by measuring the zone of inhibition. The strongest inhibition activity of the leaf extract was observed against E. coli (21 mm zone) at 200 mg mL-1 of leaf extract followed by Staphylococcus aureus which showed 16 mm inhibition zone at 200 mg mL-1 of leaf extract (Table 2). The results showed that ethanol extract of O. basilicum has an antimicrobial effect against E. coli (Gram negative bacteria) and Staphylococcus areous (Gram positive bacteria) strains.

Table 1: Physical properties of leaf extract of Ocimum basilicum
Image for - Antimicrobial Activity of Ethanolic Extracts of Ocimum basilicum leaf from Saudi Arabia

Table 2: Antimicrobial activity of Ocimum basilicum leaf extracts against E. coli and Staphylococcus areus
Image for - Antimicrobial Activity of Ethanolic Extracts of Ocimum basilicum leaf from Saudi Arabia

Image for - Antimicrobial Activity of Ethanolic Extracts of Ocimum basilicum leaf from Saudi Arabia
Fig. 1(a-b): Inhibitory effects of ethanol leaf extract of Ocimum basilicum against (a) E. coli and compare to (b) Control

Table 3: Antimicrobial activity of the positive control penicillin-G (10 μg disk-1)
Image for - Antimicrobial Activity of Ethanolic Extracts of Ocimum basilicum leaf from Saudi Arabia

Based on these results, the ethanol extract has a stronger and broader spectrum of antimicrobial activities compared to positive control used in this study (Table 3) which is Penicillin-G (10 μg disk-1).

Figure 1 shows the inhibitory effects of ethanol leaf extract of Ocimum basilicum against E. coli compare to the control (without extract). The inhibitory effects of ethanol leaf extract of Ocimum basilicum against Staphylococcus areous compare to the control was shown in Fig. 2. Similar results against E. coli and Staphylococcus aureus were obtained in a study done by Adebolu and Oladimeji (2005).

Image for - Antimicrobial Activity of Ethanolic Extracts of Ocimum basilicum leaf from Saudi Arabia
Fig. 2(a-b): Inhibitory effects of ethanol leaf extract of Ocimum basilicum against (a) Staphylococcus areous and compare to (b) Control

The strong inhibitory activities against these microorganisms showed that Ocimum basilicum can be used as a natural agent against some human pathogens. Many previous studies (Wannissorn et al., 2005; Bozin et al., 2006; Lopez et al., 2005; Sokovic et al., 2006) have reported the antimicrobial activities of Ocimum basilicum against various microbes.

CONCLUSION

The results of the present study suggest that Ocimum basilicum extracts possess compounds with potent antimicrobial properties against E. coli and Staphylococcus aureusas human pathogens.

ACKNOWLEDGMENT

The Author would like to thank King Fahd University of Petroleum and Minerals for their support to complete this work.

REFERENCES

  1. Bozin, B., N. Mimica-Dukic, N. Simin and G. Anackov, 2006. Characterization of the volatile composition of essential oils of some lamiaceae spices and the antimicrobial and antioxidant activities of the entire oils. J. Agric. Food Chem., 54: 1822-1828.
    CrossRef  |  PubMed  |  Direct Link  |  


  2. Daneshian, A., B. Gurbuz, B. Cosge and A. Ipek, 2009. Chemical components of essential oils from Basil (Ocimum basilicumL.) grown at different nitrogen levels. Int. J. Nat. Eng. Sci., 3: 8-13.
    Direct Link  |  


  3. Davies, J., 1994. Inactivation of antibiotics and the dissemination of resistance genes. Science, 264: 375-382.
    CrossRef  |  Direct Link  |  


  4. Faleiro, M.L., M.G. Miguel, F. Ladeiro, F. Venancio and R. Tavares et al., 2003. Antimicrobial activity of essential oils isolated from Portuguese endemic species of Thymus. Lett. Applied Microbiol., 36: 35-40.
    CrossRef  |  Direct Link  |  


  5. Hanif, M.A., M.Y. Al-Maskari, A. Al-Maskari, A. Al-Shukaili, A.Y. Al-Maskari and J.N. Al-Sabahi, 2011. Essential oil composition, antimicrobial and antioxidant activities of unexplored Omani basil. J. Med. Plants Res., 5: 751-757.
    Direct Link  |  


  6. Jirovetz, L., G. Buchbauer, M.P. Shafi and M.M. Kaniampady, 2003. Chemotaxonomical analysis of theessential oil aroma compounds of four different Ocimum species from Southern India. Eur. Food Res.Technol., 217: 120-124.
    Direct Link  |  


  7. Kandil, O., N.M. Radwan, A.B. Hassan, A.M.M. Amer, H.A. El-Banna and W.M. Amer, 1994. Extracts and fractions of Thymus capitatus exhibit antimcrobial activities. J. Ethnopharmacol., 44: 19-24.
    CrossRef  |  PubMed  |  


  8. Khaki, A., F. Fathiazad, M. Nouri and A.A. Khaki, 2011. Effects of basil, Ocimum basilicum on spermatogenesis in rats. J. Med. Plants Res., 5: 4601-4604.
    Direct Link  |  


  9. Khalil, A., B.F. Dababneh and A.H. Al-Gabbiesh, 2009. Antimicrobial activity against pathogenic microorganisms by extracts from herbal Jordanian plants. J. Food Agric. Environ., 7: 103-106.


  10. Lopez, P., C. Sanchez, R. Batlle and C. Nerin, 2005. Solid- and vapor-phase antimicrobial activities of six essential oils: Susceptibility of selected foodborne bacterial and fungal strains. J. Agric. Food Chem., 53: 6939-6946.
    CrossRef  |  PubMed  |  


  11. Okazaki, K., S. Nakayama, K. Kawazoe and Y. Takaishi, 1998. Antiaggregant effects on human platelets of culinary herbs. Phytother. Res., 12: 603-605.
    Direct Link  |  


  12. Sacchetti, G., A. Medici, S. Maietti, M. Radice and M. Muzzoli et al., 2004. Composition of functional properties of the essential oil of Amazonian Basil, Ocimum micranthum Willd. Labiatae in comparison with commercial essential oils. J. Agric. Food. Chem., 52: 3486-3491.
    Direct Link  |  


  13. Marwat, S.K., M.A. Khan, Fazal-ur-Rehman, A.H. Akbari, M. Shoaib and M.A. Shah, 2011. Interpretation and medicinal potential of Ar-Rehan (Ocimum basilicum L): A-review. Am.-Eurasian J. Agric Environ. Sci., 10: 478-484.


  14. Service, R.F., 1995. Antibiotics that resist resistance. Science, 270: 724-727.
    CrossRef  |  PubMed  |  


  15. Sokovic, M. and L.J.L.D. van Griensven, 2006. Antimicrobial activity of essential oils and their components against the three major pathogens of the cultivated button mushroom, Agaricus bisporus. Eur. J. Plant Pathol., 116: 211-224.
    Direct Link  |  


  16. Wannissorn, B., S. Jarikasem, T. Siriwangehaiand and S. Thubthimthed, 2005. Antibacterial properties of essential oils from Thai medicinal plants. Fitoterapia, 76: 233-236.
    CrossRef  |  


  17. Yamasaki, K., M. Nakano, T. Kawahata, H. Mori and T. Otake et al., 1998. Anti HIV-1 activity of herbs in Labiatae. Biol. Pharm. Bull., 21: 829-833.


  18. Adebolu, T.T. and S.A. Oladimeji, 2005. Antimicrobial activity of leaf extracts of Ocimum gratissimum on selected diarrhoea causing bacteria in Southwestern Nigeria. Afr. J. Biotechnol., 4: 682-684.
    Direct Link  |  


  19. Kalemba, D. and A. Kunicka, 2003. Antibacterial and antifungal properties of essential oils. Curr. Med. Chem., 10: 813-829.
    CrossRef  |  PubMed  |  Direct Link  |  


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