Henna: A Potential Cause of Oxidative Hemolysis and Neonatal Hyperbilirubinemia

Abstract

Objective. To evaluate the in vitro oxidative potential of lawsone (2-hydroxy-1,4 naphthoquinone). Lawsone is a chemical present in henna, the crushed leaves of which are used worldwide as a cosmetic agent to stain the hair, skin, and nails.

Methodology. Venous blood from glucose-6-phosphate dehydrogenase (G6PD)-normal and G6PD A^- subjects were incubated with various amounts of lawsone for 2 hours at 37°C. Reduced glutathione and methemoglobin (MHb) levels were measured before and after incubation.

Results. Final molar concentrations of lawsone in normal blood of 1.4, 2.8, 5.7, and 8.6 x 10^-3 mol/L increased MHb percentages from 0.5% to 2.2%, 8.3%, 9.5%, and 12.5%, respectively. In a G6PD A^- blood, MHb percentages were 19.8%, 32.2%, 44.9%, and 53.9%. At a lawsone concentration of 2.8 x 10^-3 mol/L, blood from 15 healthy adults formed MHb percentages of 7.4% ± 3.3% (±1 SD); in blood from 4 G6PD A^- adults, percentages were 44.5%, 40.6%, 41.3%, and 42.8%. Simultaneous measurements of reduced glutathione revealed preincubation values of greater than 40 mg/100 mL of red cells in blood of healthy and G6PD A^- subjects. Postincubation values were greater than 40 in blood of healthy subjects and less than 40 in blood of G6PD A^- subjects.

Conclusions. These in vitro observations indicate that lawsone is an agent capable of causing oxidative hemolysis. In regions of the world where there is a high incidence of G6PD deficiency and unexplained hyperbilirubinemia, oxidative hemolysis secondary to the cutaneous application of henna could be the initiating event.