Standardized Curcuma longa-Cannabis sativa extract derived from a traditional Thai formulation for psoriasis: anti-inflammatory activity, keratinocyte modulation, and skin-targeted delivery.

Thorajak P.; Junlatat J.; Srisongkram T.; Tuntiyasawasdikul S. · Journal of ethnopharmacology · 2026

**Background & Methods** This in vitro study evaluated a standardized Curcuma longa-Cannabis sativa (CLCS) combined extract derived from a traditional Thai topical formulation by characterizing its phytochemical composition, anti-inflammatory properties, and skin delivery kinetics. The research compared the combination extract to individual components using macrophage and keratinocyte cell models, alongside ex vivo permeation studies using porcine skin and Franz diffusion cells. **Key Findings** • CLCS standardized extract contained curcumin (22.12 ± 1.62 mg/g), demethoxycurcumin (12.89 ± 1.02 mg/g), bisdemethoxycurcumin (18.79 ± 1.54 mg/g), ar-turmerone (75.35 ± 3.94 mg/g), and cannabidiol (35.47 ± 2.39 mg/g), with IC50 values of 41.22 ± 1.70 μg/mL in keratinocytes and 22.91 ± 0.51 μg/mL in macrophages. • At 12.5 μg/mL, CLCS inhibited nitric oxide production by 48.97 ± 0.88% and prostaglandin E2 by 91.15 ± 3.66%, while modulating psoriasis-associated gene expression in TNF-α/IL-17A-stimulated HaCaT keratinocytes. • Cottonseed oil formulation containing 20% CLCS achieved optimal skin deposition of curcuminoids without detectable marker concentrations in receptor compartments over 24 hours, indicating preferential epidermal/dermal localization with minimal systemic penetration. **Dosage & Administration** The extract was tested at concentrations of 12.5 μg/mL in cellular assays. Topical formulation consisted of CLCS incorporated into cottonseed oil at 20% concentration. Specific clinical dosing recommendations were not provided. **Safety & Adverse Effects** Not reported. The study did not assess adverse effects, tolerability, or safety parameters in human subjects. **Evidence Quality** This is a preclinical research letter/review with significant limitations. The study employed only in vitro cell culture models and ex vivo porcine skin, lacking human clinical validation. No human subjects were enrolled, limiting applicability to clinical practice. Results cannot be directly extrapolated to therapeutic efficacy in psoriasis patients. The 2026 publication date suggests this represents emerging evidence requiring substantial clinical translation before clinical recommendations can be made.

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