International Journal of Plant Research

p-ISSN: 2163-2596    e-ISSN: 2163-260X

2016;  6(3): 53-56

doi:10.5923/j.plant.20160603.01

 

Comparative Antibacterial Activity of Methanolic, Ethanolic and Aqueous Extract of Garcinia kola (Bitter kola) and Cola nitida (Kola nut)

Ezeigbo O. R. , Ejike E. N. , Nwachukwu I. , Ejike B. U.

Department of Biology/Microbiology, Abia State Polytechnic, Aba, Nigeria

Correspondence to: Ezeigbo O. R. , Department of Biology/Microbiology, Abia State Polytechnic, Aba, Nigeria.

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Copyright © 2016 Scientific & Academic Publishing. All Rights Reserved.

This work is licensed under the Creative Commons Attribution International License (CC BY).
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Abstract

Alternative herbal medicine has been used for centuries to treat various infections. Natural plants contain phytochemical properties similar to synthetic antibiotics. Due to multiple and repeated issues with antibiotic efficacy, it has become essential to evaluate biological properties of plants from different geographical origins. A comparative antibacterial activity of metanolic, ethanolic and aqueous extracts of Garcinia kola (bitter kola) and Cola nitida (Kola nut) were carried out against some test organisms (Salmonella species, Escherichia coli, Shigella species and Pseudomonas species). Agar well diffusion method was used in determining the antibacterial activity of the plant parts at different concentrations (100%, 75%, 50%, 25% and 12.5%) using methanolic, ethanolic and aqueous extracts of the samples. The results showed that the antibacterial activity of G. kola extract on the test organisms was significant for E. coli (p-values of 0.005); for Salmonella and Pseudomonas spp respectively (p-value of 0.001) and for Shigella spp (p-value of 0.016). For C. nitida, three bacterial isolates (Salmonella species, Shigella species and Pseudomonas species) were significantly inhibited having P-values of 0.000 for Salmonella and Pseudomonas respectively and p-value of 0.001 for Shigella species; however, E. coli was not significantly inhibited by C. nitida extracts (p-value of 0.203). Methanol extracts of the studied plants showed a wider spectrum of activity than ethanol and aqueous extracts. This study revealed the importance of these plant parts as a novel source of antimicrobial agents due to the increasing drug resistance among microorganisms. The infused extracts from the plants can therefore be considered by pharmaceutical industries in the production of cheap, affordable and available drugs for the cure of infections caused by these organisms in situations where expensive conventional drugs are unaffordable.

Keywords: Garcinia kola, Cola nitida, Methalolic, Ethanolic and aqueous extracts, Test organisms

Cite this paper: Ezeigbo O. R. , Ejike E. N. , Nwachukwu I. , Ejike B. U. , Comparative Antibacterial Activity of Methanolic, Ethanolic and Aqueous Extract of Garcinia kola (Bitter kola) and Cola nitida (Kola nut), International Journal of Plant Research, Vol. 6 No. 3, 2016, pp. 53-56. doi: 10.5923/j.plant.20160603.01.

1. Introduction

The need for new antimicrobial agents is closely linked with the problem of emergence of strains that are resistant to most synthetic antibiotics. Despite the existence of potent antibiotic and antifungal agents, resistant or multi-resistant strains are continuously appearing, imposing the need for a permanent search and development of new drugs. It is therefore very necessary that the search for newer antibiotic sources be a continuous process. Natural plants contain phytochemical properties similar to synthetic antibiotics and therefore have been used in folk medicine to treat infections [1-3]. Plants are the cheapest and safer alternative sources of antimicrobials [4-6].
G. kola commonly called bitter kola belongs to the family Guttiferae, grows in forest and cultivated for its economic importance. It is widely distributed in the tropics especially West African countries such as Nigeria and Sierra Leone. It is a tree plant of about 12m high with fruits produced from July to October. The fruits have subglobose, reddish yellow and about 2.5 inches in diameter, containing 2-4 ellipsoid brown seeds embedded in an orange coloured pulp [7]. The seeds have bitter taste, somewhat resembling that of the raw coffee bean, with residual slight sweetness. The seeds are chewed as stimulants among the natives. The seeds are used in folk medicine, many herbal formulations and have therapeutic benefits largely due to the presence of various secondary metabolites such as flavonoids, apigenin, kolaviron, biflavonoid-ametoflavone, saponins, tannins, resin [8, 9]. Scientific evaluations revealed that the stem bark and seeds are used for acute fever, cough, liver disorders and anti-vomiting agent [8, 10]. The seeds are also used as a remedy for inflammations of respiratory tract, bronchitis, throat troubles, stomach ache and gastritis [11, 12]. The seed extract is very efficacious for hepatitis, antiseptic and is active against Gram-positive and negative bacteria [8]. The decoction of the root is used as aphrodisiac, evacuant, anticancer and is also recommended for dysentery, headache, malignant tumours and respiratory ailments [10]. The root is chewed for cleaning teeth and toothache [8].
C. nitida (Kola nut) belongs to Malvaceae, of the cocoa family. It is native to the main forest of tropical West Africa, but is now grown in many other humid climates like Sri Lanka. There are many species of kola plant but two species are of economic importance: Cola nitida and Cola acuminata. Kola nut exercises an exciting action in the brain without giving rise to any mental and physically painful effect. Moderate quantities are beneficial but harmful when eaten in excess by stimulating gastric acid secretion [13]. C. nitida contains both caffeine and tannin and therefore not advisable for individuals with stomach ulcers [14]. C. nitida is used for the treatment of morning sickness, migraine headache and indigestion and for cleaning teeth and gum [15]. It is used in controlling vomiting in pregnancy and as a stimulant to keep awake and withstand fatigue by students, drivers and other menial workers [16]. This study compares the antimicrobial activity of different extraction agents on G. kola (bitter kola) and C. nitida (kola nut) on some test organisms.

2. Materials and Methods

Sample Collection and Processing: The seeds of G. kola and C. nitida were obtained from kola nut dealers at Umungasi market, Aba and authenticated by a plant taxonomist in the Department of Biology/Microbiology, Abia State Polytechnic, Aba. The seeds were washed with distilled water and dried at room temperature, dehusked and grinded into power with a mechanical grinder.
Extraction of Plant Materials: The method of Aishmma and Mitscher [17] was used to obtain the plant extract. The active ingredients of each of the grounded particles of G. kola and C. nitida were extracted using methanol, ethanol and hot water respectively. Hundred grams (100g) of each of the grounded samples were added to 350ml distilled water, 95% of methanol and ethanol respectively and left to stand for 72 hours. The extracts were filtered separately using sterile Whatman’s no1filter paper and the filtrates were evaporated to dryness and stored in a deep freezer for further use.
Test Organisms: The organisms used for this study include Escherichia coli, Salmonella spp, Shigella spp and Pseudomonas spp. The test organisms were obtained from the National Veterinary Research Institute, Umudike, Umuahia, Abia State. They were obtained as pure clinical isolates and were maintained on fresh nutrient agar slants and resuscitated for antibacterial testing.
Antimicrobial Susceptibility Screening: The antimicrobial screening was carried out using agar well diffusion method as described by Cheesbrough [18]. One milliliter of sterile nutrient agar was poured into each of the petri-dishes. After setting, an overnight broth culture of Pseudomonas spp, Salmonella spp, Shigella spp and Escherichia coli were introduced into the surface of the sterile plates and sterile glass spreader was used for even distribution. Three wells of about 6mm were made asceptically with a sterile cork borer and 0.2ml of the extract of different concentrations was introduced into the wells. The extracts were allowed to diffuse into the medium for about I hour and then incubated at 37°C for 24 hours. The diameters of zones of inhibition were taken.
Statistical Analysis: The data was analyzed using Statistical Package for Social Sciences (SPSS) version 20.0. The statistical tool employed was one way Analysis of Variance (ANOVA) to determine if there was any significance among the solutions. Statistical significance tests included the use of p-value to assess for the role of chance. In this study, p-value = 0.05 was used to disapprove the null hypothesis.

3. Results

Table 1 shows the antimicrobial activity of different concentrations of methanolic, ethanolic and aqueous extract of G. kola on some test organisms. From the result, all the test organisms were inhibited by the different extracts of G. kola. The methanol extract yielded the highest zones of inhibition ranging from 23.5-30.8mm for the test organisms. This is followed by ethanol extract ranging from 17.1-24.5mm while aqueous extract had the least inhibition from 13.1-21.2mm. The result also revealed that higher concentration produced higher zones of inhibition. The univariant test showed that all the test organisms were effectively inhibited by G. kola extracts having p-values of 0.005 for E. coli, 0.001 for Salmonella spp and Pseudomonas spp respectively and 0.016 for Shigella spp.
Table 1. The Antimicrobial Activity of Different Concentrations of Methanolic, Ethanolic and Aqueous extracts of G. kola on some Test Organisms
     
Table 2 shows the antimicrobial activity of different concentrations of methanol, ethanol and aqueous extracts of C. nitida on some test organisms. From the result, methanol (30.8-36.6mm) was the most effective solvent for extraction, followed by ethanol (23.8-29.7mm) while aqueous extract had the least zone of inhibition (18.4-24.5mm). The result also revealed that zone of inhibition increased with concentration of the extracts. The univariant test showed that Salmonella spp, Shigella spp and Pseudomonas spp were effectively inhibited by C. nitida extracts having p-values of 0.000 for Salmonella spp and Pseudomonas spp respectively and 0.001 for Shigella spp. E. coli (p-value= 0.203) was not significantly inhibited.
Table 2. The Antimicrobial Activity of Different Concentrations of Methanolic, Ethanolic and Aqueous extracts of C. nitida on some Test Organisms
     

4. Discussion

Comparative analyses of the antibacterial activity of G. kola and C. nitida extracts using different extraction solvents were studied. The result revealed the antibacterial potency of the plants extracts studied. G. kola was able to inhibit the test organisms significantly while C. nitida, effectively inhibited Salmonella spp, Shigella spp and Pseudomonas spp but less significant on E. coli. These findings agree with the reports of some authors [19-22].
On the solvent used for extraction, the result revealed that methanol was a better extraction agent than ethanol and water. The methanol extract of the test plants were more effective in producing inhibition zone against the test organisms than ethanol and aqueous extracts. This finding also collaborated with the findings of some authors [21-24]. The bioactive agents were also better extracted at higher concentrations.

5. Conclusions

Methanol, ethanol and aqueous extracts of G. kola and C. nitida possess antibacterial abilities. All the test organisms were significantly inhibited except E. coli that was less susceptible to C. nitida treatment. In terms of the susceptibility of the test organisms to the extraction solvents, methanol extract > ethanol extract > aqueous extract. Thus, methanol extraction of the test plants was more effective in producing inhibition zones on the test organisms than ethanol and aqueous extracts. The test plants therefore possess potentials for manufacturing potent drugs that could be used for the treatment of infections caused by test organisms such as typhoid fever, gastroenteritis, throat infections and cough.

ACKNOWLEDGEMENTS

The authors wish to acknowledge the assistance of Dr. D. A. Awomukwu for the identification of the plant samples.

References

[1]  Dilhuydy JM (2003). Patients attraction to complementary and alternative medicine (CAM): a reality which physicians can neither ignore nor deny. Bull. Cancer., 90:623-628.
[2]  Kitula RA (2007). Use of medicinal plants for human health in Udzungwa mountains forest: a case study of New Dabaga Ulongambi Forest Reserve, Tanzania. J. Ethnobiol Ethnomed, 3:7.
[3]  Ajibesin KK, Rene N, Bala DN, Essiett UA (2007). Antimicrobial activities of the extracts and fractions of Allanblackia floribunda. Biotechnology, 7: 129-133.
[4]  Pretorius CJ, Watt E (2001). Purification and identification of active components of Carpobrotus edulis L. J. Ethnopharmarcol. 76:87-91.
[5]  Sharif MDM, Banik GR (2006). Status and utilization of medicinal plants in Rangamati of Bangladesh. Res. J. Agric. Biol. Sci. 2(6): 268-273.
[6]  Doughari JH, El-Mahmood AM, Manzara S (2007). Studies on antibacterial activity of root extracts of Carica papaya L. Afri. J. Microbiol Res, 6:037-041.
[7]  Mukhatr MD, Shuaibu WA (1999). Screening for antimicrobial activity of some extracts of the Garcinia kola. African Journal of Material and Natural Sciences, 1(1): 117-121.
[8]  Gill LS (1992). Ethnomedical uses of Plants in Nigeria. University of Benin Press, Nigeria pp 276.
[9]  Okunji CO, Ware TA, Hicks RP, Iwu MM, Skanchy DJ (2002). Capillary electrophoresis determination of biflavanones from Garcinia kola in three traditional African medicinal formulations. Planta Med., 68, 440–444.
[10]  Odugbemi T (2006). Outlines and Pictures of Medicinal Plants from Nigeria. University of Lagos Press. pp. 53-64.
[11]  Ajebesone PE, Aina JO (2004). Potential African Substitutes for Hops in Tropical Beer Brewing. J. Food Technol. Afr. 9:13-16.
[12]  Adegboye MF, Akinpelu DA, Okoh A (2008). The bioactive and phytochemical properties of Garcinia kola (Heckel) seed extract on some pathogens. Afr. J. Biotechnol., 7(21): 3934-3938.
[13]  Ibu JO, Iyama AC, Ijije CT, Ishmael D, Ibeshim M, Nwokediuko S (1986). Effect of Cola acuminate and nitida on gastric acid Secretion. Scand. J. Gastroenterol., 129: 39–45.
[14]  Newall C, Anderson LA, Phillipson JD (1996). Herbal Medicines: A Guide for Health-Care Professionals. London, England: Pharmaceutical Press; pp 84.
[15]  Esimone CO, Adikwu MU, Nworu CS, Okoye FBC, Odimegwu DC (2007). Adaptogenic potentials of Camellia sinensis leaves, Garcinia kola and Kola nitida seeds. Sci Res Essays, 2(7): 232–237.
[16]  Chukwu LU, Odiete WO, Briggs LS (2006). Basal Metabolic Responses and Rhythmic Activity of Mammalian Hearts to Aqueous Kola nut Extracts. Afri J Biotechnol., 5(5): 484–486.
[17]  Aishamma A, Mitscher LE (1979). Comprehensive survey of indigenous plants for potential economic value, screening results of 327 species for alkaloid and antimicrobial agents. J. Nat. Prod. 42(6).
[18]  Cheesbrough M (2002). Medical Laboratory Manual for Tropical countries ELBS edition. Tropical Health Technology Publications, UK. 2: 2-392.
[19]  Jaiyeola CO (2001). Preparation of kola soft drinks. J. Food. Technol. Afr., 6: 25-26.
[20]  Atolaiye BO, Adebayo MA, Jagha OO, Olonisakin A, Agbo CO (2009). Evaluation of the potency of certain substances as antioxidants in the assessment of red cell viability. Journal of Medicinal Plants research, 3(6): 485-492.
[21]  Indabawa II, Arzai AH (2011). Antibacterial activity of Garcinia kola and Cola nitida seed extracts. Bayero Journal of Pure and Applied Sciences, 4(1): 52-55.
[22]  Abalaka ME, Adeyemo SO, Okolo MO (2015). Investigation into the medicinal values of Cola species- cola nitida and Cola acuminate. Scientific Agriculture, 10(1): 31-34.
[23]  Fabeku O (2006). Traditional Med: The Arts, Ways and Practice. In: Outlines and Pictures of Medicinal Plants from Nigeria, Odugbemi, T. (Ed.). University of Lagos Press, Nigeria, pp: 13-20.
[24]  Amalu PC, Chukwuezi FO, Ugwu OPC (2014). Antimicrobial effects ofBitter kola (Garinia kola) nut on Staphylococcus aureus, Escherichia coli and Candida albicans. Journal of Dental and Medicinal Sciences, 13(4): 29-32.