Plant extracts for the topical management of psoriasis: A systematic review and meta-analysis

Psoriasis sufferers frequently use preparations of plant extracts. Physicians need to be aware of the current evidence concerning of these products. This review evaluates the efficacy and safety of preparations of plant extracts used topically for psoriasis. Searches were conducted of PubMed, EMBASE, Cochrane library, two Chinese databases and article reference lists. Randomized Controlled Trials investigating extracts of single plants were included. Preparations of multiple plants and combinations of plant extracts plus conventional therapies were excluded. Two authors conducted searches, extracted data, and assessed Risk of Bias. Outcomes used in meta-analyses were: clinical efficacy, Psoriasis Area and Severity Index (PASI), Dermatology Life Quality Index (DLQI), and symptom scores. The 12 included studies investigated extracts of: Mahonia aqulifolium (n=5), Aloe vera (n=3), Indigo naturalis (n=2), Kukui nut oil (n=1), and Camptotheca acuminate nut (n=1). Methodological quality was variable. Six studies provided data suitable for meta-analysis of clinical efficacy versus placebo (RR 3.37, 95% CI: 1.36-8.33). Experimental studies indicate components of Indigo, Mahonia and Camptotheca have anti-inflammatory, anti-proliferative and other actions of relevance to psoriasis. The clinical trial evidence provides limited support for preparations containing extracts of Mahonia aquifolium, Indigo naturalis and Aloe vera for the topical management of plaque psoriasis based on multiple studies. No serious AEs were reported. Due to the small size of most studies and methodological weaknesses, strong conclusions cannot be made. The magnitudes of any effects cannot be measured with accuracy, so it is difficult to assess the clinical relevance of these preparations.