Topical herbal formulae in the management of psoriasis: systematic review with meta-analysis of clinical studies and investigation of the pharmacological actions of the main herbs

This systematic review and meta-analysis of randomized controlled trials (RCTs) examined the topical use of multi-herbal formulations for the management of psoriasis vulgaris. Studies were identified from PubMed, Cochrane library, EMBASE, and the Chinese databases CNKI and CQVIP. Methods were according to the Cochrane Handbook and meta-analyses used RevMan 5.1. Nine studies met the inclusion/exclusion criteria. The comparisons were with placebo and/or anti-psoriatic pharmacotherapy (APP) with two studies having three arms. The pooled meta-analysis data indicated the topical herbal formulae improved overall clinical efficacy (defined as 50% improvement or greater) when compared with: topical placebo (plus oral herbal co-intervention); topical APP alone; and topical APP (plus pharmaceutical co-intervention). Improvement was evident in Modified Psoriasis Area and Severity Index (PASI) score when topical herbal formula was compared to placebo (plus oral herbal co-intervention). No serious adverse events were reported. The most commonly used herbs were Sophora flavescens root and Lithospermum erythrorhizon root. Experimental studies reported that these herbs and/or their constituents have anti-inflammatory, anti-proliferative, anti-angiogenic, and tissue repair actions. These actions may at least partially explain the apparent benefits of the topical multi-herbal formulations in psoriasis.