The antimicrobial activities of extracts of Terminalia avicennoides (Mexican tea) and Acalypha wilkesiana (copper leaf) were screened against Pseudomonas aeruginosa, Bacillus subtilis, Escherichia coli, Klebsiella, Salmonella typhi, Staphyloccus aureus and Candida albicans. The extracts showed a better activity against all organisms but T. avicennoides showed high activity against C. albicans. The antimicrobial activities for both plant extracts were more pronounced at a high concentration than at low concentration of the extracts. The extracts of the two plants can be used in the treatment of diseases where the test organisms are implicated.Keywords: Antimicrobial activities, Terminalia avicennoides, Acalypha wilkesian

Akpomie, OO

Olorungbon, S

English

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African Journal of Biotechnology Vol. 10 (2), pp. 180-182, 10 January, 2011     Available online at http://www.academicjournals.org/AJB DOI: 10.5897/AJB10.457 ISSN 1684–5315 © 2011 Academic Journals      Short Communication  Antimicrobial screening of Terminalia avicennoides and Acalypha wilkesiana  Akpomie, O. O*. and Olorungbon, S.  Department of Microbiology, Delta State University, Abraka, Delta State, Nigeria.  Accepted 17 December, 2010  The antimicrobial activities of extracts of Terminalia avicennoides (Mexican tea) and Acalypha wilkesiana (copper leaf) were screened against Pseudomonas aeruginosa, Bacillus subtilis, Escherichia coli, Klebsiella, Salmonella typhi, Staphyloccus aureus and Candida albicans. The extracts showed a better activity against all organisms but T. avicennoides showed high activity against C. albicans. The antimicrobial activities for both plant extracts were more pronounced at a high concentration than at low concentration of the extracts. The extracts of the two plants can be used in the treatment of diseases where the test organisms are implicated.  Key words: Antimicrobial activities, Terminalia avicennoides, Acalypha wilkesiana.   INTRODUCTION   The problem of the emergence of strains of micro-organisms that are resistant to most of the present day antibiotics requires the use of new antimicrobial agents. Plants have been found to possess the broadest spectrum of synthetic activity and are the source of many useful antimicrobial compounds (Ayodele and Banuso, 2004). Many plants, for example, Thymus vulgaris have both antibacterial and antiviral properties, Cassia fistula and Mesua ferrea have antibacterial and antifungal activities (Ali et al., 2004). Many naturally occurring substances of plant origin cover a wide range of antimicrobial activity than synthetic chemical. The use of plants offers a better opportunity of providing antimicrobial activity against such organisms that are resistant to known antimicrobial agents (Amadi et al., 2007). There are still so many plants whose medicinal uses have not been ascertained. Plants which constitute an active part of the ecosystem have been found to  be  useful to  man   both   as   sources   of   foods  and     *Corresponding author. Email: bunmakp@yahoo.com  Abbreviations: TAEE, Terminalia avicennoides ethanol extract; TAAE, Terminalia avicennoides acetone extract; AWAE, Acalypha wilkesiana acetone extract; TAWE, Terminalia avicennoides water extract; AWWE, Acalypha wilkesiana water extract; TAS, Terminalia avicennoides. medicine. Only about 1 to 10% is used as food by both man and animals (Smith et al., 1996), so the remaining part can be used for the treatment of ailments. In view of the resistance of so many organisms to the available antibiotics and the fact that many organisms are still resistant to the plants that have been researched on, there is the need to find out more on the potentiality of diverse plants as antimicrobial agents. This study there-fore aims at assessing the antimicrobiall efficacy of Terminalia avicennoides and Acalypha wilkesiana on selected microorganisms.    MATERIALS AND METHODS  Sample collection  The leaves and stem barks of T. avicennoides and A. wilkesiana were collected from Gyellesu, Zaria and were identified in the Herbarium of the Department of Biological Sciences, Ahmadu Bello University, Zaria. Organisms used in the study were gotten from pure culture isolates obtained from Microbiology Laboratory, Ahmadu Bello University, Zaria. They were sub cultured on nutrient agar (oxoid) slants and stored at 4°C.    Extraction of plant materials  The plant materials were washed, air dried and separately ground to  powder  in  a  moulinex  blender.  The  powder of each plant was  Akpomie and Olorungbon        181    Table 1. Phytochemical analysis of the plant extracts.   Component TAEE TAAE TAWE AWEE AWAE AWWE Alkaloids + + + - - - Tannins  + + + + + + Saponins + + + + + + Flavoniods + + + + + +  + Present; - absent.    Table 2. Minimal inhibitory concentration of ethanol, acetone and water extracts of the plant samples.  Test organism TAEE TAAE TAWE AWEE AWAE AWWE P. aeruginosa  15.625 15.625 125 62.5 62.5 125 S. typhi 15.625 31.25 250 125 125 250 E. coli 31.25 125 250 31.25 31.25 62.5 B. subtilia 62.5 125 250 62.5 62.5 125 Klebsiella phenmoniae - 250 62.5 125 125 - S. aureus - 125 250 31.25 31.25 - C. albicans - 125 250 125 125 250    stored in an airtight container and kept in the refrigerator at 4°C. 200 g of each powdered sample was extracted with 150 ml of 40% ethanol using soxhlet extractor. The resulting extract was evapo-rated to a constant volume and labeled T. avicennoides ethanol extract (TAEE). Soxhlet extraction was also done with 150 ml redis-tilled acetone. It was evaporated to dryness at 70°C and labeled T. avicennoides acetone extract (TAAE) and A. wilkesiana acetone extract (AWAE). 200 g of powder was dissolved in 100 m distilled water and maintained in a waterbath for about 4 h at 45°C and labelled T. avicennoides water extract (TAWE) and A. wilkesiana water extract (AWWE).   Phytochemical analysis  The method of Trease and Elaise (1996) was used to detect the presence of phytochemicals. The filtrate from each extraction was tested for the presence of tannins, alkanoids, saponins and flavo-noids.     Antimicrobial screening  The antibacterial and antifungal screening was done with all extracts against Pseudomonas aeruginosa, Staphyloccus typhi, Escherichia coli, Klebsiella sp., Staphyloccus aureus and Candida albicans. Plates of nutrient agar (for antibacterial screening) and potato dex-trose agar (for antifungal screening) were seeded heavily with test organisms. Holes (diameter 0.5 cm) were made in them and filled with 250 mg/ml of the sample solution. The plates were incubated at 37°C for 24 h for bacterial isolates and 48 h for fungal isolates. The diameter of zones on inhibition was measured and recorded (Amadi et al., 2004).   Determination of minimal inhibitory concentration  One gram of each extract was dissolved in 4 ml nutrient broth to give 250 mg/ml. Serial dilutions were made to give 125, 65.5, 31.25 and 15.625 mg/ml. Three drops of overnight broth culture of the test organisms were inoculated into the dilutions and inoculated at 37°C for 24 and 48 h for fungi. The lowest concentrations of the extracts that inhibited the growth of the test organisms were recorded as the minimal inhibitory concentration.   RESULTS AND DISCUSSION  The phytochemical analysis of the plant extracts as shown in Table 1 indicates that all the extracts of the two plants contain flavonoids, tannins, saponins and tannins. The extracts of A. wilkesiana did not contain alkaloids. Brantner and Grein (2004) were able to isolate the compounds in plant extracts and found them to be anti-microbial. Table 2 shows that the extracts had varying degrees of antimicrobial activity against the test organisms. The ethanol extract of T. avicennoides (TAS) was more effective against the bacterial and fungal isolates. It inhibited the growth of 1, 2, 3 and 4 at a lower concentration than the other extracts. This can be attributed to the fact that activity of the biological active components of plants is better enhanced in the presence of ethanol and the higher extraction capacity of ethanol (Ali et al., 2004). Acetone extract of TAS also inhibited the growth of all the organisms but was more effective against P. aeruginosa and S. typhi at a low concentration. It inhibited the growth of the other organisms but at a high concentration. The other extracts were able to inhibit the growth of orga-nisms at very high concentration and with some, there was no inhibition. An increase in the concentration of the extract brought about an increased antimicrobial activity, which agrees with the work of Yongabi et al. (2002) that higher concentrations of antimicrobial substances showed appreciable  growth  inhibition of bacteria. All the extracts  182         Afr. J. Biotechnol.    Table 3. Diameter of zones of inhibition of the extracts (cm).  Test organism TAEE TAAE TAWE AWEE AWAE AWWE P. aeruginosa  20 16 10 10 12 10 S. typhi 16 14 8 5 10 5 E. coli 14 11 8 12 14 12 B. subtilia 8 9 6 5 10 5 K. phenmoniae 10 8 12 0 14 0 S. aureus 12 10 8 0 14 0 C. albicans 12 10 8 0 10 0    apart from TAEE were able to inhibit the growth of the fungus, C. albicans, but at high concentrations. The poor antimicrobial activity of some of the extracts might be attributed to the solvent extraction methods and the concentration of the active ingredients in the extracts. Uzel et al. (2005) showed that tannins and flavonoids were extracted with ethanol, water and ether, whereas saponins and alkaloids were not. From the results of the diameters of zones of inhibition (Table 3), the AWEE, AWWE and AWWE showed mode-rate activity against P. aeruginosa, S. typhi, E. coli and B. subtilis. There was no activity against Klebsiella, S. aurerus and C. albicans. The TAEE, TAEE, TAWE and AWAE showed appreciable activity against all the organisms. TAEE was more effective against the fungus (C. albicans) than the other extracts.      Conclusion   The extracts of the two plants (T. avicennoides and A. wilkesiana) have appreciable antimicrobial activity against the test organisms. The solvent used in the extraction methods determines the chemicals (active ingredient) extracted which affects the concentration and invariably the antimicrobial activity of the plants. TAEE, TAAE, TAWE and AWAE were able to inhibit C. albicans. The extracts of the two plants are thus recommended in the treatment of diseases in which the test organisms are implicated. Further work is encouraged on: 1. the choice of solvents for the extraction of the active ingredients in the plant samples; 2. production of pure active compound, which can be used to formulate drugs against these organisms or used in combination with resistant drugs that are being used presently; 3. toxicological and clinical trials on experimental animals.   REFERENCES  Ali-Abbas, Abu-Sayeed M, Bhuyan M, Sohel MSA FI, Yeasmin MS (2004). Antimicrobial screening of cassia fistula and Messua ferrea. J. Med. Sci. 4(1):  24-29.   Amadi ES, Nwakpu K, Nworie O, Ogbu O (2004). Evaluation of the vitro effects of some medicinal plants on Escherichia  coli.  J. Health Visual Sci. 6: 176-179. Amadi ES, Onyeka CA, Onyeaba RA, Ugbogu OC, Okoli I (2007). Antimicrobial screening of Breynes nivosus and Ageratum conyzoides. J. Biol. Sci. 7(2): 354-358. Ayodele PO, Banuco A (2004). In vivo testing of the efficacy of root extracts of Cabbage (Anthocleista mobilis) for the treatment of Newcastle disease. Niger. J. Arts Sci. Technol. 2: 66-72. Brantner A, Grein E (1994) Antibacterial activity of Plant Extracts used externally in traditional medicine. J. Ethopharmacol. 44: 35-40. Smith G, Clegg M, keen C, Grivet L (1996). Mineral value of selected plant food in West Africa. Int. J. Food Sci. Nutr. 47: 41-53. Trease GE, Evans WC (1996). Pharmacology 25th Edition, Balliere and Tyndall, London. pp. 250-546.  Uzel A, Sorkun K, Oneag O, Cogulu D, Gencay O, Salih B (2005) Chemical compositions and antimicrobial activities of four different Anatolian propolis samples. Microbiol. Res. 160: 189-195.  Yongabi KA, Agho MO, Adamu ILM, Adebitan SA, Angeil JE, Jalo LK (2002). Antibacterial effects of the extracts of Carica papaya, Urtica dioica and Aloe barbadensis on some bacterial isolates from Lycopersicon esculentum mill. J. Chem. Soc. 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Antimicrobial screening of Terminalia avicennoides and Acalypha wilkesiana

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Antimicrobial screening of Terminalia avicennoides and Acalypha wilkesiana

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