Experimental and clinical trial investigations of phyto-extracts, phyto-chemicals and phyto-formulations against oral lichen planus: A systematic review

Bio-assay guided phytoextracts and derived phytoconstituents reported having multipotent biological activities and nearly 60-80% of the global population still using natural regimens as an alternative therapeutic source. This study focused on the ethnopharmacological and experimental evidence of natural remedies that are effective in treating oral lichen planus (OLP), a chronic T-cell mediated autoimmune disease that is associated with oral cancer transmission.A number of studies have shown that antioxidants and antiinflammatory phytoextracts and phyto-constituents are effective against OLP. In this systematic review, we summarize the details of experimentally assessed ancient Traditional Chinese Medicine (TCM), Indian Ayurveda or Ayurvedic Medicine, and Japanese Kampo Medicine (JKM) regimens (crude extracts, individual phytochemicals, and phyto-formulations) that reduce oral lesion, severity index and pain associated with OLP based on studies conducted in vivo, in vitro, and in randomized controlled trials (RCTs).Experimental, clinical and RCT investigation reports were gathered and presented according to PRISMA-2020 format. Briefly, the information was obtained from PubMed, ScienceDirect, Wiley journal library, Scopus, Google Scholar with ClinicalTrials.gov (a clinical trial registry database operated by the National Library of Medicine in the United States). Further, individual phytochemical structures were verified from PubChem and ChemSpider databases and visualized by ChemDraw 18.0 software.We summarized 11 crude phytoextracts, 7 individual phytochemicals, 9 crude formulations, 8 specific TCM and JKM herbal cocktails, and 6 RCTs/patents corroborated by multiple in vitro, in vivo and enzyme assay methods. Briefly, plants and their family name, used plant parts, reported phytochemicals and their chemical structure, treatment doses, and duration of each experiment were presented more concisely and scientifically.Documentation of evidence-based natural ethnomedicines or remedies could be useful for promoting them as potential, cost-effective and less toxic alternatives or as complementary to commonly prescribed steroids towards the control of OLP.