Development of an Antimicrobial Topical Skin Cream with Using Wood Apple (Limonia acidissima L.) Pulp Against Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans

Skin inhabiting microbes mostly non-pathogenic and commensals on the skin. Among them Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans often responsible for symptomatic skin infections. Cellulites, impetigo, ecthyma, red lesions and candidiasis are some of the common microbial skin diseases caused by skin pathogens. Wood apple (Limonia acidissima L.) is an underutilized fruit in Sri Lanka and, all parts of this plant have medicinal value. Considering the high therapeutic value, the aqueous extract of wood apple pulp was used. Antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa and antifungal activity against Candida albicans was evaluated by using the standard well diffusion method. Above tested bacterial and fungal species were suspended in 3 mL of sterile distilled water separately and 108 CFU/mL population count was prepared. Aliquots of 100 µL of each suspension were inoculated and uniformly spread on Muller Hinton agar plates separately in triplicates. Wells were filled aseptically placing 50 µL of wood apple extracts, antimicrobial compounds specifically as the positive control for bacteria and fungi and sterile distilled water as the negative control. The plates were incubated at 37 °C for 24 - 48 hours and the diameter of the growth inhibition zones around the wells were measured. Furthermore, minimum inhibition concentrations of each extract were also evaluated. Comparisons were performed using one-way ANOVA followed by Tukey’s Pairwise Comparisons. The antimicrobial topical skin cream was prepared using 0.5 g mL-1 of wood apple pulp with sterile distilled water, mixed with the formulated standard ingredients. The results revealed that the aqueous extracts of wood apple pulp concentrations range from 0.15 g mL-1 to 1g mL-1 showed the antimicrobial potential of above skin pathogens variably ranged inhibition zone diameter 16 mm to 34 mm. The antimicrobial effect of the formulated cream against these pathogens was repeatedly tested. Further testing procedures needed to be followed before recommending wood apple topical antimicrobial skin cream as a marketable product.