INTRODUCTION:

The use of herbs and medicinal plants is a universal phenomenon. Every culture on earth has relied on the huge variety of natural chemistry found in healing plants for their therapeutic properties. Modern medicines have always depended on herbal remedies for plants as fundamental sources of therapeutic ingredients Etusim (2005).

Aloe vera is one of the oldest healing plants known to man. It is as old as civilization and throughout history it has been used as a popular folk medicine. Aloe vera is an ornamental and medicinal plant from a member of liliaceous family.

The name was derived from the aeabic ‘alloeh’ meaning ‘bitter’ because of bitter liquid found in the leaves. It is also known as ‘lily of the desert’ the plant of immortality and the medicine plant with qualities to serve as alternate medicine Nduka (2003).

Aloe vera is essential with components that are bactericidal such include: saponins, anthraquinones etc. A synergistic action of these components provides a bactericidal effect. Examinations testing various percentage of Aloe vera solutions against tissue cultures of four pathogens-Pseudomonas aerigonosa, Escherichia coli, Proteus mirabilis and Salmonella typhi. Pseudomonas aeruginosa are present in a number of secondary urinary treat infections in men. E. coli is a potent bacterium common to the rectal cavity of every living mammal. Proteus mirabilis is also common cause of urinary infection in the elderly and young males and Salmonella typhi causes illness such as typhoid fever, paratyphoid fever and food borne illness (Ryan and Rayca, 2004). It was noted that all the microorganisms were killed within 24hours of exposure to high levels of Aloe Vera (Bruce, 1967)

This work is aimed at:

1. Comparing antibacterial effects of different Aloe vera parts on the three bacterial species.

2. Comparing the effects of Ethanol Crude Extract (ECE) and Water Crude Extract (WCE) on the three bacterial species (Pseudomonas aeruginosa, Salmonella typhi and Proteus mirabilis).

MATERIALS AND METHODS:

The present study was designed to evaluate antibacterial activity of Aloe vera by using its leaf, stem and root extracts. The study was performed at the Centre for Tropical Disease Research Laboratory, Abia State University Uturu.

Collection of Plant Material:

The Aloe vera plant used in this work was obtained from Root Crop Research Institute Umuahia Abia state. Its identification was confirmed by Professor Chuks .I. Ogbonnaya (Ecotaxonomist) from the Department of Plant Science Biotechnology, Abia State University, Uturu.

Test organisms:

The test organisms used in this work were Pseudomonas aeruginosa, Proteus mirabilis and Salmonella typi. The organisms were gotten from the Microbiology Laboratory Abia State University, Uturu. The identified bacteria species were confirmed by Dr. (Mrs.) Nkechi Nwachukwu (Microbiologist) from the Department of Microbiology, Abia State University Uturu.

Culture Media:

The culture media used was Muller Hinton Agar. It was manufactured by LS Biotech Company Santiago, USA. This media was prepared on the producer’s instruction printed on the container. Specific weight of the powder was obtained in conical flask and reconstituted using specific volumes of distilled water. The conical flasks were properly stopped with cotton wool wrapped in aluminum foil. The flask was then autoclaved to sterilize at 121⁰C for 15mins. It was then allowed to cool to about 45-50⁰ before dispensing into the sterilized Petri-dish and left to gel on the flat surface.

The Petri-dish was left overnight in the incubator before use for sterility.

PROCESSING OF PLANT MATERIAL:

The Aloe vera leaves, stems and roots were washed with distilled water. After washing, each parts were cut to pieces using a sterile knife and was allowed to dry at 105⁰c for 4hrs in a hot air oven. The dried material was finally grinded using the method adopted by Arunkunar and Muthuselvam 2009.

EXTRACTION OF CRUDE EXTRACTS:

ECW and WCE were prepared using the method adopted by Irshad et al (2003).

SENSITIVITY TESTING USING ALOE VERA CRUDE EXTRACTS:.

The antibacterial activity of Aloe vera leaves, stems, and roots extracts was tested using Agar well diffusion technique as described by Agarry et al (2005). Wells of 5mm diameter were cut on sterile Mueller Hinton agar plates using a cork borer and swabbed with an overnight broth culture of the organism. About 0.1ml of the CWE and ECE of Aloe vera leaves, stems, and roots were filled into each of the wells and incubated at 37^oc^. Antibacterial activity in terms of zone of inhibition (mm) was observed and recorded after 24hrs of incubation using the method adopted by Lawrence et al (2009).

RESULTS:

The antibacterial property of Aloe vera leaves, stems and roots extracted using different solvents showed varying degree of response towards the selected pathogen.

The zone of inhibition on Aloe vera leaf extracts ranged from 14.5mm – 17.5mm being maximum for Proteus mirabilis and minimum for Pseudomonas aeruginosa. CWE have proved the highest inhibition with S. tyhpi. It read 16mm and 16.5mm inhibition for P. aeruginosa and P. mirabilis respectively. See Table 1.

The maximum inhibition was observed with Aloe vera stem (17mm) for Pseudomonas aeruginosa using ECE, followed by Proteus mirabilis (16mm). No response was observed in ECE for Salmonella typhi. CWE has no inhibition. See Table 2.

With Aloe vera roots, the maximum inhibition was observed in ECE and CWE for Proteus mirabilis (21.5mm) (19.5mm) respectively. No response was observed in CWE and ECE for Salmonella typhi and Pseudomonas aeruginosa. See Table 3.

Table 1. Results for Aloe vera Leaf Extracts showing measurement of zone of inhibition.

ORGANISMS	COLD WATER	ETHANOL
Salmonella typi	17mm	16.5mm
Pseudomonas aeruginosa	16mm	14.5mm
Proteus mirabilis	16.5mm	17.5mm

Table 2. Results for Aloe vera Stem Extracts Showing Measurement of Zone of Inhibition.

ORGANISMS	COLD WATER	ETHANOL
Salmonella typi	____	____
Pseudomonas aeruginosa	____	17mm
Proteus mirabilis	____	16mm

Table 3. Results for Aloe vera Root Extracts Showing Measurement of Zone of Inhibition.

ORGANISMS	COLD WATER		ETHANOL
Salmonella typi		____	____
Pseudomonas aeruginosa		____	____
Proteus mirabilis		19.5mm	21.5mm

DISCUSSION:

The present study was undertaken to assay the antibacterial activity of Aloe vera leaves, stems and root. The antibacterial activity recorded in this work agrees with the observation of Boudreau and Beland (2006), who observed high antibacterial activities on the ECE on Aloe vera leaf. It was used against some human pathogenic bacteria: Pseudomonas aeruginosa, Salmonella typhi, and Proteus mirabilis with two different solvents: CWE and ECE. ECE was most effective than CWE of Aloe vera leaves, stems and roots as shown in Table 1. This agrees with the observation of Ahmed et al (1998) who noted that alcohol extract were better solvents for extraction of antimicrobially active substances compared to water and hexane. Thiruppathi et al (2010) reported that ethanol exhibited maximum antibacterial activity against all bacterial pathogens used in their work. Similarly, Lawrence et al (2009) reported that nearly all of the identified components from plants active against micro-organisms are most often obtained through initial ethanol and methanol extraction. This could explain higher antimicrobial activity of ECE observed in this work.

The study also showed that Aloe vera leaf extracts has antibacterial activity on Salmonella typhi, Pseudomonas aeruginosa and Proteus mirabilis, stem extracts on ECE of both Pseudomonas aeruginosa and Proteus mirabilis and root extracts on CWE and ECE of Proteus mirabilis. But there was no effect on CWE and ECE of salmonella typhi and CWC of both Pseudomonas aeruginosa and Proteus mirabilis on Aloe vera stem and CWE and ECE on Salmonella typhi and Pseudomonas aeruginosa on Aloe vera root. This agrees with the report of Freeman and Mizett (1979) and Prescot et al (2000) that not all organisms are inhibited at he same rate.

Again, Proteus miralibis is most susceptible than the other organisms, this proves that Proteus mirabilis infections usually respond better to antimicrobial therapy than those caused by other related organisms. This confirmed that the plant extracts could be used for the treatment of various infections including urinary infections, Abdominal and wound infections, ulcers, pressure sores, burns, damaged tissues, septicemia and occasionally meningitis and chest infections as these are the common cause of Proteus Mirabilis (Chessbrough 2000).

Among the three Aloe vera parts used, Aloe vera leaf of both ECE and CWE were inhibited on the growth of the three organisms. This agrees with the work of Arunkumar and Muthuselvam (2009) and that of Kedarnath et al (2012).

While there is paucity of information on the roots and stems of crude extracts of Aloe vera, the observation of no inhibition on Salmonella typhi by both ECE and CWE from root and stem is remarkable. However water extract of stem which showed no inhibition in Pseudomonas aeruginosa and Proteus mirabilis turned out to give 17mm and 16mm inhibition respectively with ECE. Again the high inhibition exhibited on Proteus mirabilis showed that the roots and stem of Aloe vera as well contain potent antibacterial properties. This finding however, may contribute to further research on screening other antibacterial components in Aloe vera stems and roots and provide a basis for application of Aloe vera. stems and roots in treatment of infective diseases.

REFERENCE:

1. Agarry,O.O., Olaleye, M.T., and Michael, B.(2005).Comparative antimicrobial activities of Aloe vera gel and leaf. African Journal of Biotechnology, 4(12): 1413-1414.

2. Ahmed, J., Mehmood, Z., and Mohammad, F. (1998). Screening of some Indian medicinal plants for their antimicrobial properties. Journal of Ethnopharmacology 62:183-193.

3. Arunkumar, S., and Muthselvam, M. (2009). Analysis of phytochemical constituents and Antimicrobial Activity of Aloe vera L. against clinical pathogens. World Journal of Agricultural Sciences 5(5):572-576.

4. Boudreau, M.D., and Beland, F.A, (2006). An evaluation of the biological and toxicological properties of Aloe vera barbardensis (Miller). Aloe vera. J. Environmental Carcinogenesis and Ecotoxicology Reviews, 24(1): 103-154.

5. Bruce, W. (1967), Investigations of antibacterial activity in the Aloe vera Journal of South African Med.41:984-989.

6. Cheesebrough, M.(2000). District Laboratory practice in Tropical Country. Gospsons papers publishers India.180-194.

7. Etusim .P.E. 2005, the Forgotten Role of Herbs in Modern Health Care. Department Lecture Isues Department of Animal and Environmental Biology, Abia State University Uturu.

8. Freeman, V.J., and Mizett, G.H. (1979). The identify of gram negative bacterium. J. Gen. Microbio:48(1)107-110..

9. Irshad, S., Muneeba, B., and Hira, Y. (2003). Invitro antibacterial Activity of Aloe Barbadensis Miller (Aloe vera). International Research Journal of Pharmaceutical.1(2):59-64.

10. Kedarnath, N.K., Surekhe,Ramesh, S., Mahantesh,S.P., and Patil, C.S.(2012) Phytochemical screening and Antimicrobial Activity of Aloe vera L. World Research Journal of medicinal and Aromatic Plants .1(1):11-13.

11. Lawrence, R., Priyanka, T., Ebeneze, J. (2009). Isolation, purification and evaluation of Antibacterial Agents from Aloe vera. Brazillian Journal of Microbiology.40:906-915.

12. Nduka F.O. 2003: Aloe vera: the Magic Plant. Faculty Seminar Series, Faculty of Biological and Physical Sciences, Abia State University, Uturu.

13. Prescot, P., Harley, J.P., Klin, D.A. (2000). Microbiology 4^th edition, Macgraw Hill publishers, USA 677-679.

14. Rayan, K.G.,and Ray, C.G.(2004). Shems medical Microbiology(4^th edit.) Mcgraw Hill publishers.362-368.

15. Thiruppathi, S.J., Ramasubiamanian, V., Sivakunar, T., and Thirumalai, A.V.(2010). Antimicrobial Activity of Aloe vera Burm. F. against pathogenic Microrganisms. Journal of Biosciences Research, 1(4):251-258.

Received on 29.02.2013 Modified on 20.02.2013

Asian J. Research Chem. 6(6): June 2013; Page 570-572