Curcumin in the Management of Oral Lichen Planus: An Umbrella Review of Systematic Reviews

Objectives: Oral lichen planus (OLP) is a prevalent immune-mediated mucocutaneous condition that affects 53.6% of individuals with skin involvement. Corticosteroids remain the first line of treatment; however, their prolonged use is associated with well-known side effects. In recent years, there has been significant research on herbal medicines as a potential adjunct. Among these, turmeric (Curcuma longa), an age-old traditional remedy, has shown efficacy in the management of OLP, indicating its potential as an adjunct to standard treatments. This umbrella review aimed to assess the efficacy and safety of curcumin in the management of OLP. Methods: Databases including Medline via PubMed, Cochrane, Scopus, Google Scholar, and ProQuest search engines were analyzed for systematic reviews (SRs) published in English. The A Measurement Tool to Assess Systematic Reviews (AMSTAR 2) checklist was used to assess the methodological quality of the included studies. The overlap of the study was evaluated using the corrected covered area (CCA) and visualized through a Graphical Representation of Overlap for Overviews (GROOVE) tool. Results: Six SRs with one meta-analysis were included. Using the AMSTAR2 checklist, two were rated as moderate-quality and four as critically low, with considerable study overlap (CCA = 38%). Conclusion: Based mainly on two moderate-quality SRs, the use of topical curcumin may provide short-term symptomatic relief for OLP. However, the data on adverse events were lacking across all SRs to establish any safety conclusions. Therefore, more rigorously designed high-quality randomized controlled trials (RCTs) with longer follow-up periods are needed to clarify its definitive role in the therapeutic management of OLP.