Evaluation of cosmetic lipsticks for hazardous heavy metals and determination of antimicrobial potency

Abstract

Background: Lipstick, a cosmetic product containing pigment, wax materials, oils and emollient that apply color, is the most widely used cosmetic make-up to enhance the beauty of lips. Consciously or unconsciously, lipsticks have cast a spell over cultures for years and its possible health implications on the consistent wearer's remain a subject of controversy. This study evaluated commercial lipsticks purchased from selected beauticians' shops in Ibadan for antimicrobial potency and hazardous heavymetals. Methods: One gram (1g) of representative lipsticks samples was weighed on analytical weighing balance and dissolve in 10 mL of acetone. A stock concentration of 100mg/mL was prepared using 50% acetone as diluents. Thereafter, 5mL of the stock was pipette in to 5mls of 5% acetone to make a concentration of 50mg/mL . A quantity of 0.8g of each representative samples were weighed and 8mL of HNO3: HCl (1:3) were added to the samples in each beaker. The samples were heated and the preparation was allowed to cool and filtered to removed undissolved waxy materials, while the digested solutions were made up to mark 40 ml with sterile distilled water. The sample solutions were analyzed for Cr, Pb, Cd, Mn, Fe and Zn using FlameAtomicAbsorption Spectrophotometer. Culture of E. coli, S. aureus, K. pneumonia, Streptococcus sp, and Pseudomonas aeruginosa seeded in moltenMueller Hinton agar were challenged with (100mg/mL and 50mg/mL) concentrations of selected acetone dissolved lipsticks samples using agar well diffusion technique. Results: Lead was found in varied concentrations in all the 15 samples examined, while Cadmium, Magnesium, Zinc and Iron were found in 7 of the 15 samples, Chromium was found in 3 of the total samples examined. Thirteen (13) of the 15 samples of lipsticks examined exhibited antimicrobial property against Escherichia coli, Staphylococcus aureus and Klebsiella spp at either 100 mg/mLand/or 50mg/mL. Conclusion: The degree of heavy metals detected from the samples examined could be inimical to user's health coupled with the susceptibility of some of the lipsticks sample to bacteria of clinical potential. There is therefore a need for extensive testing to assess and assure the efficacy of lipsticks regularly before delivery to markets.