Ursane-type triterpenoids, such as ursolic acid and related compounds, have been investigated for their potential in managing psoriasis primarily due to their anti-inflammatory, antioxidant, and immunomodulatory properties. Several preclinical studies using cell cultures and animal models have shown that ursane-type triterpenoids can inhibit key inflammatory pathways involved in psoriasis, such as the NF-κB and MAPK signaling pathways. These compounds have demonstrated the ability to decrease the production of pro-inflammatory cytokines (e.g., TNF-α, IL-6, IL-17) and to reduce keratinocyte proliferation, both of which are central to the pathogenesis of psoriasis.

However, clinical evidence in humans is very limited. Most of the available data are derived from laboratory and animal studies, and there are only a few small-scale or preliminary human trials, if any, assessing the efficacy of ursane-type triterpenoids in psoriasis patients. As such, while the scientific rationale exists based on mechanistic and animal research, there is currently insufficient high-quality clinical evidence to recommend these compounds as a validated treatment for psoriasis. Therefore, the evidence supporting their use is promising but limited (rating: 2/5), and further well-designed clinical trials are needed to establish both safety and efficacy in human subjects.