Formulation of herbal lipstick from Hibiscus sabdariffa (Roselle) and evaluation of its antimicrobial activity

Aims: Hibiscus sabdariffa, a tropical shrub is a member of the Malvaceae family found in tropical and subtropical regions worldwide with excellent pharmaceutical properties.There is a lack of reports on the antimicrobial activity of natural pigment in lipstick formulation.The present study was aimed to determine the antibacterial activity of the aqueous extract of H. sabdariffa in lipstick formulation against pathogenic bacteria.Methodology and results: Several susceptibility tests were conducted to evaluate bacterial growth inhibition, including well diffusion assay, MIC and MBC determinations, growth reduction and time-kill analysis.Well diffusion assay revealed that the lipstick formulation incorporated with H. sabdariffa extract has significant antibacterial activity against both Gram-positive and Gram-negative bacteria, with the diameter of inhibition zone ranging from 15.4 2.6 to 18.4 3.6 mm and 11.7 2.9 to 15.0 6.0 mm, respectively.For MIC and MBC determination, the formulated lipstick showed a bactericidal effect against all Gram-positive bacteria.The growth reduction assay revealed that the formulated lipstick can inhibit the growth of Gram-positive bacteria with 99% growth reduction.Besides that, time-kill analysis showed that Gram-positive and Gram-negative bacterial cells, Staphylococcus aureus and Pseudomonas aeruginosa were significantly reduced after exposure to the formulated lipstick at different concentrations.The findings also revealed that the antibacterial activity of the formulated lipstick was dose-and time-dependent.Conclusion, significance and impact of study: Aqueous extract of H. sabdariffa possesses significant antibacterial activity against pathogenic bacteria.This research highlights the potential of H. sabdariffa extract incorporated in the lipstick formulation as an antibacterial agent and natural colourant.