Antibacterial profiling of methanolic leaf extracts and herbal cosmetic cream formulations containing the leaf extracts of Urtica dioica, Amaranthus viridis and Aloe vera

Synthetic antibacterial drugs are not only expensive but often associated with toxicity, adverse reactions and resistance. There is therefore the need for drugs of natural origin with little or none of the problems associated with synthetic drugs. This study evaluated the antibacterial potency of the methanolic leaf extracts and herbal cosmetic cream formulations containing the leaf extracts of, Urtica dioica, Amaranthus viridis and Aloe vera which were extracted with methanol by cold maceration method. The antimicrobial susceptibility of some organisms to the leaf extracts and their cream formulations was determined by agar-well diffusion method using working concentrations of 100 mg/mL, 200 mg/mL and 400 mg/mL of the extracts with distilled water as the negative control. Neomycin® in the concentrations of 6.25 µg/mL, 12.5 µg/mL, 25 µg/mL, and 50 µg/mL was used as the positive control for the leaf extracts while 2% w/v  mupirocin (Supirocin®) cream and penicillin® ointment were used as positive control for herbal cream evaluation. The MIC of the leaf extracts was determined by agar dilution method using various concentrations (20 mg/mL to 210 mg/mL). The leaf extracts and the formulated creams exhibited antimicrobial activities comparable with the standard antimicrobial compounds and formulations. Urtica dioica exhibited the highest antibacterial activity. The cream formulation containing a combination of 20% each of Urtica dioica and Aloe vera appeared the most potent against the bacteria used. These results suggest that herbal topical formulation containing the leaf extracts of these plants has potentials in the treatment of dermal bacterial infections.