Comparing the topical preparations of Indigo naturalis from Chinese and Iranian origin in the treatment of plaque-type psoriasis: A preliminary randomized double-blind pilot study

A Comprehensive Systematic Review of Natural Biomedicines for Immune-Mediated and Inflammatory Dermatologic Diseases

BACKGROUND

Natural biomedicines (NBMs) are frequently used to manage immune-mediated and inflammatory dermatologic diseases (IMIDDs). This systematic review evaluates the efficacy, safety, and clinical relevance of NBMs in IMIDDs, providing an evidence-based analysis to guide dermatologic practice.

METHODS

Following PRISMA guidelines, a systematic search was conducted in PubMed, Embase, Medline, and Google Scholar for randomized controlled trials (RCTs) investigating NBMs in IMIDDs from 1990 to 2023. Studies were included if they met predefined eligibility criteria: RCT design, relevant IMIDD condition, NBM intervention, and quantitative outcome measures. Risk of bias was assessed using the Jadad scale. Results were synthesized qualitatively due to heterogeneity in study designs and outcome measures.

RESULTS

Of 1364 records screened, 95 RCTs were included, encompassing 5265 participants across 23 countries. Indigo naturalis, fish oil (⍵-3), and aloe vera demonstrated the most consistent efficacy in managing psoriasis, systemic lupus erythematosus (SLE), atopic dermatitis (AD), and lichen planus (LP). Indigo naturalis significantly improved erythema, scaling, and PASI scores in psoriasis patients. Fish oil showed benefits in SLE disease activity indices and AD severity, while aloe vera demonstrated improvements in SCORAD and LP severity criteria. Most NBMs exhibited favorable safety profiles, although adverse event reporting was inconsistent.

DISCUSSION

While these findings highlight the potential of NBMs in dermatologic care, methodological limitations, including small sample sizes, heterogeneity in study designs, and lack of direct comparisons to conventional therapies, limit definitive conclusions. Additionally, not all natural agents can be easily searched and captured in systematic reviews, which may have restricted the scope of included NBMs. Future research should emphasize high-quality RCTs, standardized outcome measures, and comparative studies against conventional treatments.

TRIAL REGISTRATION

The review protocol is registered with Open Science Framework (OSF) ( https://doi.org/10.17605/OSF.IO/UH9XJ ).

Evidence and potential mechanism of action of indigo naturalis and its active components in the treatment of psoriasis

BACKGROUND

Indigo naturalis is effective against psoriasis. Indigo, indirubin and tryptanthrin, the main active components of indigo naturalis, have anti-inflammatory properties.

OBJECTIVE

To evaluate the efficacy and safety of indigo naturalis and its active components in the treatment of psoriasis.

METHODS

Seven databases were searched for studies of indigo naturalis and its active components for the treatment of psoriasis.

RESULTS

The findings demonstrated a higher response rate in the Chinese herbal medicine (CHM) formula groups than in the control group for Psoriasis Area and Severity Index 60 (PASI60) (Rate difference [RD] = 0.22, p < .0001). Among all adverse events, only the incidence of gastrointestinal adverse reactions was higher in the CHM formula group than in the control group (RD = 0.09, p < .0001). In preclinical in vivo studies, indirubin showed better performance in improving the phenotype of psoriasis-like mice compared to that in controls, including the PASI score (mean difference [MD] = -3.58, p < .0001), epidermal thickness (MD = -29.13, p < .0001), interleukin-(IL) 17 A mRNA expression (MD = -2.27, p = .0066) and IL-23 mRNA (MD = -5.36, p = .01).

CONCLUSION

Indigo naturalis combined with conventional treatments is useful for treating psoriasis. Indigo naturalis display anti-proliferative, anti-inflammatory and anti-angiogenic effects by regulating the TAK1, JAK3/STAT3, Wnt/β-catenin, Akt/PKB, FAK and AP-1/c-Jun pathway.

Exploring the Therapeutic Potential of Natural Compounds in Psoriasis and Their Inclusion in Nanotechnological Systems

Psoriasis is a chronic inflammatory disease that affects around 2-3% of the world's population. The treatment for this autoimmune disease still remains centered around conventional methods using synthetic substances, even though more recent advancements focus on biological therapies. Given the numerous side effects of such treatments, current research involves plant extracts and constituents that could prove useful in treating psoriasis. The aim of this narrative review is to highlight the most known representatives belonging to classes of natural compounds such as polyphenols (e.g., astilbin, curcumin, hesperidin, luteolin, proanthocyanidins, and resveratrol), alkaloids (e.g., berberine, capsaicin, and colchicine), coumarins (psoralen and 8-methoxypsoralen), and terpenoids (e.g., celastrol, centelloids, and ursolic acid), along with plants used in traditional medicine that could present therapeutic potential in psoriasis. The paper also provides an overview of these compounds' mechanisms of action and current inclusion in clinical studies, as well as an investigation into their potential incorporation in various nanotechnological systems, such as lipid-based nanocarriers or polymeric nanomaterials, that may optimize their efficacy during treatment.

Tryptanthrin ameliorates imiquimod-induced psoriasis in mice by suppressing inflammation and oxidative stress via NF-κB/MAPK/Nrf2 pathways

Nowadays, approximately 3% of the world's population suffers from psoriasis, an inflammatory dermatosis with high recurrence. Tryptanthrin (TRYP) is a natural alkaloid that possesses anti-inflammatory activities on multiple diseases. The present study aimed to unravel whether TRYP could relieve psoriasis and how it works. Imiquimod (IMQ)-induced psoriatic mouse models were administered saline (model), TRYP (25 and 100 mg/kg), or methotrexate (MTX, 1 mg/kg) and considered as the positive control. TNF-α-induced keratinocytes (HaCaT cells) with TRYP (0, 10, 20 and 50 nM) were used for in vitro verification. Psoriasis area severity index (PASI) and spleen index were evaluated. Th17 cell infiltration in both spleens and lymph nodes was detected by flow cytometry. The expression levels of inflammatory cytokines, glutathione (GSH), malondialdehyde (MDA) and catalase (CAT), as well as superoxide dismutase (SOD), were examined by ELISA, while the NF-κB/MAPK/Nrf2 pathways-related proteins were determined by western blot. TRYP significantly attenuated psoriatic skin lesions, increased GSH, SOD, and CAT levels, reduced spleen index, accumulation of MDA, the abundance of Th17 cells in both the spleen and lymph nodes, and secretion of inflammatory cytokines in IMQ-induced psoriatic mouse models. Mechanically, TRYP suppressed IMQ-activated NF-κB (IκB and p65), MAPK (JNK, ERK1/2, and p38), and activated Nrf2 signaling pathways. Similar alterations for inflammation and oxidative stress parameters and NF-κB/MAPK/Nrf2 pathways were also observed in TNF-α-treated HaCaT cells upon TRYP treatment. Our findings suggested TRYP is effective in protecting against inflammation and oxidative stress in psoriasis-like pathogenesis by modulating the NF-κB/MAPK/Nrf2 pathways.