Introduction

Plants with different medicinal properties have been employed by traditional medical practice for the treatment of different disease conditions. In eastern Nigeria, some plants which have frothing or foaming ability have been employed as soap for bathing and for treatment of skin and wound infections. Ethnomediacally, juice and extracts from leaves of the plant are topically applied as anti-inflammatory and antimicrobial agents, especially in the treatment of skin diseases including eczemas, ring-worms and pruritus (Benjamin, 1980; Benjamin and Lamikanra, 1981; Oliver, 1986; Ayim, 1987; Akinde et al., 1999). These plant materials are either used alone or formulated into local soaps, ointments and creams which are often commercially available. Due to lack of evidence on the efficacy of herbal soap, and the poor aesthetic presentation, these products are mostly patronized by low income group in the local communities in the past. But interestingly, the popularity of herb-based soaps is increasing due to many years of accumulated experience on their efficacy on topical disorders. Currently, there are so many commercial brands of herb-based soaps with good claims of efficacy and are now enjoying increasing patronage. It is therefore important to investigate these soaps to validate the claims and also establish other useful properties which will help in promoting public acceptance and encourage wider usage.

Soaps act as emulsifiers or surfactants, softening the horny-layer of the epidermis and acts as a germicide by enhancing the permeability of microbial envelope thereby disrupting the integrity of microbial cells. Antimicrobial activity of soaps make them useful agent for bathing, laundry, washing, and cleansing of surfaces (Fuerst, 1978; Hugo and Russel, 1983).

The cleansing and germicidal properties of the soapy-plants are comparable to those of the standard soaps, which are salts of higher fatty acids. Crude preparations of soapy plants are able to soften the skin epidermis, enhance greater penetration and cleansing of sores and acne and thereby promote rapid healing and resolution of blemishes.

In this study we evaluated the antiseptic potentials of Cassia alata-based herbal soap formulated in our laboratory. Cassia alata is known to contain some secondary metabolites like resin, saponin, phenols, flavonoids, anthraquinone glycosides and alkaloids (Akinde et al., 1999). These phytoconstituents are also known to possess surface activity and other soap related properties. In previous studies, Cassia alata has been found to possess excellent wound-healing properties (Benjamin and Lamikanra, 1981; Palanichamy et al., 1991) and is also useful in the treatment of eruptive and pustular skins conditions by rubbing crushed fresh leaves on infected area (Akinde et al., 1999).

Materials and Methods

Microorganisms

Chemicals and Reagents

Collection, Identification and Processing of Plant

Extraction

Formulation of Herbal Soap

Antimicrobial Evaluation of the Herbal Soap

Results and Discussion

In the preliminary antimicrobial sensitivity screening, the ethanol extract of Cassia alata showed excellent activity against the test organisms (Table1). Many of these organisms are natural flora of the skin and also known etiologic agents of several skin and mucous membranes infections of man. In previous studies, the antimicrobial activity of Cassia alata extract has been attributed to the presence of some active secondary metabolites and high acid values due to the hydrolysis of esters, as well as to the abundance of phenolic compounds (Acharya and Chatterjee, 1975; Rai, 1978; Rai and Obayemi, 1978; Smith and Ali, 1979; Ayinde et al., 1999)

Figure 1

Table 1: Preliminary antimicrobial activity of ethanol extract of

The Cassia alata-based herbal soap demonstrated an excellent antimicrobial activity against the tested microbial skin flora (Table 2). The activity against Staphylococcus aureus is of significant interest. The skin carries large numbers of bacteria flora, mainly Gram-positive picked up from the various objects with which it comes in contact. Of these natural flora, Staphylococcus aureus commonly found on the hands, face and in deep layers of the skin is perhaps the most widely encountered and very undesirable. Staphylococcus aureus is ubiquitous and are not easily eliminated especially in the deeper skin layers, sweat gland, sebaceous gland, and the hair-follicles by routine washing and scrubbing even with some antiseptic soap (Fuerst, 1978; Hugo and Russel, 1983, Rosenberg and Cohen, 1983; Singleton; 1987). Thus, the potency of the Cassia alata herbal soap against Staphylococcus aureus is very remarkable and could be harnessed in the containment of the organism implicated as the commonest etiologic agent of boils, carbuncles, breast abscess, infantile-impetigo (Fuerst, 1978).

Figure 2

Table 2: antimicrobial evaluation of herbal formulated Soap

The herbal soap was not tested against Gram-negative bacteria, since they are not auchthchonous skin flora. However, they are only encountered when the normal Gram-positive bacteria are depleted by antibiotic application, other non-physiological conditions such as the spillage from the gastrointestinal tract (GIT) onto the skin around the anal and genital regions as well as on soles of the feet (Rosenberg and Cohen, 1983). The herbal soap was active against the spore-forming Bacillus subtilis. This organism is usually encountered by contacts with the materials handled (especially soil) and are mostly harmless, but occasionally could become opportunistic causing infections especially of the eyes (Fuerst, 1978).

The activity of the herbal soap against Candida albicans which normally inhabits part of the respiratory, gastrointestinal and female genital tracts is also important (Fuerst, 1978, Hugo and Russel, 1983; Rosenberg and Cohen, 1983). In this study, the herbal soap inhibited the growth of Candida cells. Candida albicans is known to be inherently resistant to many antimicrobial agents. Although it is a natural human body flora, it also causes some opportunistic infections in debilitated, immuno-compromised patients as well as patients on prolonged antibiotics and immunosuppressants (Hugo and Russel, 1983).

Even though the human skin cannot be made absolutely free of bacteria, the Cassia alata-based soap exhibited high antimicrobial potency against Staphylococcus aureus (Table3). The organism is the most widely encountered and undesirable auchthchonous normal skin flora difficult to be totally removed. At a reduction time of 5 mins, the herbal soap recorded a significantly (P<0.05) lower mean viable count of 2.12 x 104 cfu/ml (a reduction in microbial load of 94.78%) as against the value for the control treatment. In this study, the herbal soap formulated with Cassia demonstrated high potency against skin flora and indicates the potential of the plant as excipient in the production of antiseptic soaps for combating skin infections especially in the tropics. These findings have high economic, industrial and medical significance.

Figure 3

Table 3: Effect of Cassia alata-based herbal soap on viable cells on the palms of volunteers