Contents

end

Samaila¹ AB, ²Yarma AA, and ³Oshomoh EO  

Addresses: ¹Department of Biological Sciences, Abubakar Tafawa Balewa University, PMB 0248, Bauchi State, Nigeria, ²Yarma Memorial Hospital Gombe, Gombe State, Nigeria, ³Department of Science Laboratory Technology, Faculty of Life Sciences, University of Benin. Edo State.

Citation: Samaila AB, Yarma AA, and Oshomoh EO. Anti-fungal and Anti-bacterial activities of Sabulun salo local soap in Bauchi Metropolis, Bauchi State, Nigeria. Special Fungal Pathogens Journal (SFPJ), Vol 1, No 1, pages: 0014-0018

Correspondence: E- mail: [email protected], [email protected]  : Tel:+2348033854269

Abstract

Background: The rate at which cutaneous Candidiasis spread among infected individuals in tropical resource-poor countries remains alarming despite the multidisciplinary and multi-sectorial advances made to contain it.

Objective: To determine the antifungal and antibacterial activities of Sabulun salo; a local traditional medicated soap widely used by different tribes in Nigeria against skin infections.

Materials and Methods: Standard Microbiological methods were used to isolate and identify the fungal and bacterial agents used to test against the local soap. Anti-microbial activity of our soap against some clinical isolates of pathogenic microorganisms (Candida albicans, Staphylococcus aureus, Escherichia coli) was done using the agar dilution method. Minimum inhibitory concentration was also done to confirm the susceptibility of the soap against some clinical fungal and bacterial potential pathogens.

Results: The pattern of inhibition varies with the soap concentration and the organisms tested. The soap has more activity on S. aureus with a maximum zone of growth inhibition of 26mm at 100mg/ml followed by C. albicans (24mm). However, P. aeruginosa was resistant to the soap at all concentrations tested.

The minimum inhibitory concentration (MIC) was found to be 12.5mg/ml for S. aureus and 25mg/ml for C. albicans. The antibacterial and antifungal activities exhibited by sabulun salo in this study could be attributed to the presence of its broad-spectrum active constituents which signifies the potential use of the soap as a candidate topical therapeutic agent.

Conclusion: The results demonstrate that the soap has both antifungal and antibacterial properties and can be used for the treatment of infections caused by fungi or bacteria.

Keywords: Antifungal, Antibacterial, Activities, Sabulun salo, Metropolis, Bauchi State

Introduction

Sabulun salo is a local traditional medicated soap widely used by different tribes in Nigeria such as Hausa, Yoruba (Ose Dudu), and Nupe (Eko zhiko). It is a black soap that has been used for centuries in many African homes especially in Ghana and Nigeria. The soap is produced from a mixture of vegetable oils such as palm kernel oil and Shea butter oil (1).

The attribute of the soap includes gentleness on the skin, rich lather, protection against skin disorders (such as rashes, eczema, and scabies), treatment of skin infections (like ringworm), protection of even skin toning and smoothness of the skin (1). The benefit of soap finally managed to appeal to the European population in the 17^th century and the art of maintaining a high personal hygiene experience increased also (2).

The major fatty acids present in palm kernel oil, a major ingredient for making sabulun salo, are lauric acid (C₁₂, 48%), myristic acid (C₁₄ 16%), and oleic acid. Certain fatty acids (medium-chain saturates) and their derivatives have activity on various microorganisms (3). Monolaurin has been specifically found to have activity on potentially pathogenic microorganisms. Zadik, et al (4) reported the inactivation of S. epidermis and group β-hemolytic Gram-positive Streptococci by lipase with high monolaurin content.

The lauric acid content of the palm kernel oil has the additional beneficial function of being formed into monolaurin in human or animal bodies (5). This means that the palm kernel oil may have a higher antimicrobial effect in vivo. Although the antimicrobial activity observed is low, Kabara (3) has shown that the use of this type of inhibitory agent does not lead to the development of resistance.

Shea butter is an extract from the kernel of the Vitellaria paradox which is found in 19 countries across the African savanna zone. Shea butter contains a high level of U.V-β ray absorbing triterpenes ester including cinnamic acid, tocopherols (vitamin. A), and phytosterols. It also contains a high percentage of unsaponifiable campesterol, stigma sterols, beta, and alpha spino sterols (6). Shea butter is composed of five principal fatty acids; palmitic acid, stearic acid, linoleic acid, and arachidic acid.

Stearic acid and oleic acid account for about 85-90% of the acids (7). The analysis of the kernel reveals the presence of phenolic compounds such as garlic acid, catechin, epicatechin, gallate as well as quercetin, and trans cinamic acid (8).

Most of the commercially imported soaps cause different problems to humans including the development of resistant microorganisms (9). Hence the need for a mild universally acceptable antimicrobial soap with minimal side effects and Sabulun salo has exhibited some of these properties (10). Lauric acid is a major component of palm kernel oil which is an active ingredient for making sabulun salo. Although the antimicrobial activity shown by lauric acid is low, the use of this type of inhibitory agent does not lead to the development of microbial resistance (3).

Objectives

This research aims to determine the antifungal and antibacterial activity of sabulun salo, a local traditional medicated soap, commonly used in Bauchi State Nigeria with the ultimate goal of providing scientific bases to validate its claimed antimicrobial activity.

Materials and Methods

Study Area

The study was carried out in Bauchi metropolis in Bauchi, Bauchi state occupies a total land area of 49,119km²and lies between latitudes 9⁰ 3’ and 12⁰ 3’north and longitude 8⁰ 50’ and 11⁰ east. Yelwa is located in Bauchi metropolis, along Tafawa Balewa road. Its geographical coordinates are 10⁰ 17’ 0” north and 9⁰ 47’ 0”. Yelwa market is situated along the main road.

Sample Collection

Sabulun solo was obtained from Yelwa market. The soap was collected aseptically in polythene bags and was conveyed to the laboratory for further processing. Clinical isolates of the test organisms were also obtained from the Abubakar Tafawa Balewa University Teaching Hospital, Bauchi.

Antimicrobial Assay of Sabulun salo microbial carriage

Clinical isolates of Candida albicans, Staphylococcus aureus, and Pseudomonas aeruginous were obtained from the Abubakar Tafawa Balewa University Teaching Hospital (ATBUTH), Bauchi and the susceptibility of the organisms to sabulun salo tested and assayed using agar well diffusion method.  The overnight culture of the test organism was suspended in saline solution (0.85% NaCl) and adjusted to match the turbidity of 0.5 McFarland standards (10). The standardized suspensions were used to inoculate the surface of Muller Hinton agar plates and PDA plates using a sterile cotton swab.

The stock solution of the sabulun solo was prepared by dissolving 10g of sabulun solo in 100ml of sterile distilled water to form a stock solution of 100mg/ml and from which different concentrations of the sabulun salo (100mg/ml, 50mg/ml, 25mg/ml, and 12.5mg/ml) were prepared following serial dilution (1 in 2 dilutions). The concentrations were labeled 1-4 (11).  Five wells were made on the plate using a sterile Cork borer, 4mm in diameter, and labeled 1-4. 1ml of each concentration was transferred into each of the four wells and distilled water into the fifth well (negative control).

The plates were incubated at 37⁰c for 24 hours and room temperature for 48 hours for bacteria and fungus respectively. The plates were observed for the zone of inhibition around the wells and the zone of inhibition measured using a transparent meter rule. The entire test was conducted in duplicate and it was repeated for confirmation of the result.

Minimum Inhibitory Concentration (MIC) and Minimum Lethal Concentration (MLC)

The minimum inhibitory concentration, as well as the minimum lethal concentration, determined according to the National Committee for Clinical Standard (12) using the broth dilution method. Twelve test tubes were labeled 1-12, arranged in a test tube rack, and 1ml of double strength nutrient broth was poured into tube 2 and normal strength into 3-12 1ml of the test solution was pipette into tubes 1, 2, and 12. Tube 2 was mixed well and 1ml transferred into tube 3, and tube 3 was mixed well as above and 1ml transferred into tube 4, continuing similarly to tube 9. Tube 9 was mixed well and 1ml was discarded.

The overnight culture was standardized to a turbidity of 0.5 McFarland standards. The culture was further diluted to 1:200 by two-step addition of 1ml of diluted culture to 9ml of nutrient broth 0.5ml of Standardized culture was added to tubes 1-10. All the tubes were mixed well and incubated at 37⁰C for 18hrs. Tube 10 is the organism viability control, while tube 11 is broth sterility control, and tube 12 is test solution sterility control.

The tubes were observed for growth and the tube with less concentration showing no visible growth was noted as the minimum inhibitory concentration (MIC). All tubes showing no visible growth and the first tube showing growth, and the control were sub-cultured onto a nutrient agar incubated at 37⁰C for 24 hours. The lowest concentration showing scanty growth, that is, less than 10 colonies after the sub-culture was marked as the minimum lethal concentration (MLC)

Result

The result of the Antimicrobial assay of sabulun salo showed that the soap possesses antimicrobial activity against two of the test organisms. The pattern of inhibition varied with the sabulun salo soap concentration and the organisms tested. The largest zone of inhibition was observed against S. aureus (26mm) followed by C. albicans (24mm) at 100mg/ml.

However, Pseudomonas aeruginosa was resistant to the soap (6mm) at all the concentrations tested. The MICs of the sabulun salo soap against both S. aureus and C. albicans were 12.5mg/ml. The minimum bactericidal concentration, MBC, of S. aureus was found to be 12.25mg/ml and the minimum fungicidal concentration, MFC, of C. albicans was 25.5mg/ml (Table 1).

Table 1; Table 1 presents the observed antimicrobial activities of the first sample of the sabulun salo soap collected in terms of the zone of inhibition observed at various concentrations of the soap.

Diameters of the zone of inhibition for sample A

S/N	Test organism	Mean diameter Zones of inhibition (mm)
		100mg/ml	50mg/ml	25mg/ml	12.5mg/ml
1	Staphylococcus aureus	26	20	18	15
2	Candida albicans	20	18	15	13
3	Pseudomonas aeruginosa	6	6	6	6

 

Table 2 Minimum Inhibitory Concentration (MIC) and Minimum Lethal Concentration (MLC)

S/N	Test organism	MIC	MBC	MFC
1	Staphylococcus aureus	12.5mg/ml	12.5mg/ml	NA
2	Candida albicans	12.5mg/ml	NA	25mg/ml

Key; MIC- minimum inhibitory concentration; MBC- minimum bactericidal concentration; MFC- minimum fungicidal concentration; NA- not applicable

Discussion

Since the soap is effective against Candida species strains, it is therefore promising in efforts to provide effective intervention in topical Candida infections. The soap can also be evaluated as a possible alternative to topical antifungal agents including miconazole nitrate (Micatin, Monistat-Derm) or clotrimazole (Lotrimin, Mycelex) creams. One-time oral therapy with fluconazole (150 mg) or itraconazole (600 mg) is another attractive and effective therapy against Candida Vulvovaginitis.

The sabulun salo soap may also be considered as a good alternative topical therapy in the treatment of patients with Candidal balanitis, congenital candidosis, oropharyngeal candidiasis in the infant, nipple candidosis, oral candidiasis, candidal diaper dermatitis, subacute intertrigo, chronic intertrigo, Paronychia, and candidosis in HIV.

The findings of this study show that sabulun salo has an antimicrobial effect against S.aureus and C. albicans with a maximum zone of inhibition of 26mm and 24mm respectively. The result also showed that there is no significant difference in the zones of inhibitions and the minimum inhibitory and lethal concentration of the two samples collected.

This may mean that the antimicrobial activity of the sabulun salo soap depends on the major ingredients (lauric acid, myristic acid, and oleic acid).  S. aureus and C. albicans have been incriminated in causing skin infections including boils, thrush, impetigo, etc (13); the susceptibilities of these organisms to the soap indicate the potentials of the soap in the prevention of the spread of these organisms and treatment of such diseases.

The conventional medicated soaps are found to contain triclocarban and triclosan as active antimicrobial agents. These chemical compounds function by denaturing all disrupting cell activity and interfering with microbial metabolism. These depend on several factors such as the inherent properties of the organisms, contact time, the composition of the soaps (e.g triclosan), the concentration of individual formulation, and skin sensitivity.

Traditional black sabulun salo soap lacks a key ingredient used in killing microorganisms such as triclosan, instead of when the sabulun salo soap is scrubbed into the skin; it helps release oils on the surface of the skin that can kill bacteria and rinse microorganisms away on the skin and preventing the emergence of mutating bacteria (11).

The cell walls of S. aureus which is a gram-positive bacterium are made up of the main peptidoglycan. Peptidoglycan is found to be distorted by long-chain fatty acids that are found in palm kernel oil, an active ingredient in sabulun salo. The activity of the soap against S. aureus, therefore, could be attributable to the palm kernel oil present in the soap (10). Ugbogu (14) reported that palm kernel oil has an inhibitory effect on S. aureus and Streptococcus sp.

The major fatty acids in palm kernel oil used for the production of sabulun salo are lauric acid, myristic acid, and oleic acid. Certain fatty acids (medium-chain saturates) and their derivatives have adverse effects on various microorganisms (3). Monolaurin has been specifically found to harm the potentially pathogenic microorganism. It is well known that the inactivation of S. epidermidis and group B Gram-positive Streptococcus by lipases with high monolaurin content.

The effect of long-chain fatty acid may be the disruption of the fungal membrane leading to leakage of macromolecules such as nucleotide, inorganic acid, or phosphorylated ammonium compound (15). This explains the inhibitory effect exerted by the soap against the fungus C. albicans.

There was no observed inhibitory effect on P. aeuruginosa by the soap at all concentrations used. P. aeruginosa is a Gram-negative organism has little peptidoglycan in its cell wall and this may hinder the activity of the active components of the soap (fatty acids). The resistance of most gram-negative bacteria to antimicrobial agents is known to be due to chromosomal mutation which lowers the permeability of the bacteria to the agents or acquisition of resistance (R) plasmids and transposons.

Therefore, the resistance showed by P. aeruginosa to sabulun salo may be due to chromosomal mutation which may have resulted in the lower permeability of the bacterial cell. However, Ekwenye and Ijeomah (16) reported that palm kernel oil has inhibitory action against E. coli with no inhibition against, Pseudomonas aeruginosa and Aspergillus niger.

Although the effect of the soap was static on C. albicans raising the concentration of the soap may be cidal and also activity may be found on P. aeruginosa. It should be noted that an increase in the purity of the palm kernel oil and shea butter (used in the preparation of the sabulun salo soap) may have a significant effect on the properties and quality of the soap.

The antimicrobial activity exhibited by the sabulun salo extract against the test organisms (S. aureus and C. albicans) that are associated with various skin infections has provided scientific justification for the ethnomedicinal uses of the sabulun salo soap by Hausa, Yoruba and Nupe tribes in Nigeria.

In general, there was inhibition against all test organisms by the soap. Therefore, Sabulun salo can serve as a potential source of broad-spectrum antibiotics.  It is recommended that further studies should be conducted on sabulun salo with a view to its industrial production employing hygienic and more standard techniques.

Reference

1. Getradeghana BT. Evaluation of African traditional soap. Global Journal of Pure and Applied Science 2000; 6:174-179.
2. Gerrie S. The Origins African Black Soap; 2015. http://multiculturalbeauty.about.com/od/Global/fl/African-Black-Soap.htm
3. Kabara JJ. Health oils from the tree of life, in pharmacological effects of lipids. AOCS press London. 1978; Pp. 624-629.
4. Yehuda Z, Saar B, Estella D, Vadim S, Clariel I, Tamar H. “Colonization of Candida: prevalence among tongue -pierced and non-pierced immunocompetent, Journal of Microbiology. 2010; 80–9.
5. Emeg MG. Lauric oils as antimicrobial agents CRC press London 2000; Pp. 81-87.
6. Wiesman ZS. Chemical analysis of fruits of Vitellaria paradoxa. School of Agriculture and Forest sciences, University of Wales: Bangor, UK; 2003; Pp.131-139.
7. Maranz SZ, Wiesman J. Germplasm Resources of Vitellaria paradoxa based on variations in fat composition across the species distribution range. Agro-forestry Systems 2004; 60: 71-76.
8. Steven M, Zeev W, Nissim, G. Phenolic constituents of Shea (Vittellaria) Kernels. Journal of Agriculture and Food Chemistry. 2003; 51: 6268- 6278.
9. Ihuma JO, Asenge HG, Abioye JOK, Koggie AZ, Nmadu P, Nwakwo M. The effect of some medicated soaps on some normal micro-flora of the human skin. International journal of advanced biological research. 2013; 3: 341-347.
10. Aliyu MS, Hanwa UA., Tijjani MB, Aliyu AB. Ya’u B. Phytochemical and antibacterial properties of leaf extract of Stereospermum lanthanum (Bignoniaceae). Nigerian Journal of Basic and Applied Sciences, 2013; 17 (2): 235-239.
11. Ikpor IS, Lennox JA, Agbo BE, Udoekong NS, Ekpo IA, Iyam SO. Comparative study of the effect of locally made black soap and conventional medicated soaps Journal of Microbiology & Biotechnology Research; 2012, Vol. 2 Issue 4, p533
12. Clinical Laboratory Standard Institute (CLSI) (1999). Performance Standards for Antimicrobial disc and dilutions of susceptibility test for bacteria isolated from animals. Pennsylvania, X, USA, document (M31 – A)
13. Trent JT, Federman D, Kirsner RS. Common bacterial skin infections. Ostomy Wound Management 2001, 47: 30-34.
14. Ugbogu OC. Lauric acid content and inhibitory effect of palm kernel oil on two bacterial isolates and C. albicans. African Journal of Biotechnology 2006; 5(11):1045-1047.
15. Williams HD, Zlosnik JE, Ryall B. “Oxygen, cyanide and energy generation in the cystic fibrosis pathogen Pseudomonas aeruginosa”. Advanced Microbial Physiology 2007; 52:1–71. doi:10.1016/S0065-   2911(06)52001-6.
16. Ekwenye, UN, and Ijeomah CA. Antimicrobial effect of palm kernel oil. KMTL Science Journal 2005; 6: 22-26.

Publish your next article with any of our Journals. Send e-mail attachments to [email protected]