Abstract:
Treatment of skin infections is of global concern due to contraindications, microbial resistance to conventional creams and their associated high cost. Saps from leaves of Dacryodes edulis (De) and Anacardium occidentale (Ao) are traditionally used topically for treating skin diseases. However, the effectiveness of these leaves in skin cream formulation has not been reported. Therefore, this study was designed to investigate the effectiveness of De and Ao leaves, and creams formulated against selected skin diseases causative agents.
Methanol extracts of De and Ao leaves were partitioned separately with n-hexane, ethyl acetate, butanol and water. Phytochemical analyses were conducted using standard procedures. Antioxidant analyses using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and Ferrous Ion-Chelating (FIC) were carried out. Antimicrobial tests on twelve microorganisms were conducted using standard procedures. Six oil-in-water creams, FDe1, FDe2, FDe3 and FAo1, FAo2, FAo3, were produced from ethyl acetate fractions of De and Ao, respectively using standard pharmaceutical procedures. Creams formulated were evaluated for physicochemical properties, while antimicrobial assay of the creams was conducted on selected clinical strains of bacteria and fungi. Intradermally, Staphylococcus aureus (0.5 mL of 10-8 CFU) was injected into 40 mice (5 per group), treated with 200 mg of the creams and Tydineal cream (as reference drug) for three days and the excised side skins were subjected to microbial count. Stored creams at 0oC, 29±4oC and 46oC were evaluated for stability using viscosity and organoleptic observation for 120 days. Creams’ sub-acute toxicity test was purposively done on 30 mice (5 per group) using standard procedures. Data were analysed using descriptive statistics and ANOVA at α0.05.
Saponins (mg/100g) and carotenoids (μg/100g) in Ao and De were 1750.00±7.64, 925.00±7.64, (controls: 438.33±6.01, 711.67±4.41) and 1628.33±18.78, 1083.33±7.26, (controls: 231.67±7.26, 720.00±2.89), respectively. Scavenged free radicals of De for DPPH and FIC (86.29-34.89%, 40.24-13.13%) were significantly higher than Ao (42.46-2.27%, 21.67-0.00%), respectively. The ethyl acetate fractions were the most active antimicrobially. The colours, pH and globule sizes of De and Ao creams were light green to dark green and dark yellow to deep brown, 3.24-4.52 and 3.58-4.01, 29.12-95.99 and 55.38-188.4 μm, respectively. The FDe3 significantly inhibited Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, Trichophyton rubrum and Epidermophyton sp. (21.00±1.00, 16.00±2.00, 16.00±2.00, 11.70±0.60, 11.00±1.00 mm, respectively) than FAo3 (10.70±1.20, 8.00±0.00, 10.00±0.00, 4.00±0.00, 0.00±0.00 mm, respectively) and other formulated creams. Tydineal cream had highest inhibition on Staphylococcus aureus (87.93%) followed by FDe3 (85.89%), FAo2 (85.39%), FAo3 (85.32%), FAo1 (85.23%), FDe2 (85.21%) and FDe1 (85.03%), while the aqueous cream base was inactive. Viscosities of De and Ao creams were 3134-5060 and 2510-5495 cP, respectively with no significant difference among storage temperatures. Organoleptic properties of the creams at 0oC and 29±4oC remain unchanged, but colours were darkened in the creams at 46oC. Mice skins showed no lesions.
The formulated creams with the highest quantity of the ethyl acetate fractions (FDe3 and FAo3) were effective against the tested microorganisms with no observed skin side effects. Dacryodes edulis cream was more effective than Anacardium occidentale cream.
