Herbal therapy psoriasis
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Herbal therapy psoriasis
Psoriasis is a common, chronic, recurrent and immunemediated inflammatory disorder characterized by circumscribed, red, thickened plaques with an overlying silverwhite scale. Although the prevalence of psoriasis varies depending on ethnicity, approximately 2% of the world’s population suffers from this disease (Schon and Boehncke, 2005). It may affect any parts of the body with a predilection of scalp, knees, elbows, and lower back.
Indigo naturalis (Qing Dai) has been used commonly in traditional Chinese medicine for antipyretic, anti-inflammatory, antiviral, antimicrobial purposes and to treat psoriasis and leukemia (Liang et al., 2013). Indigo naturalis is a dark blue powder obtained from the stems and leaves of the plant Baphicacanthus cusia and other indigo-containing plants such as Polygonum tinctorium, Isatis indigotica and Indigofera tinctoria. While indigo naturalis had been used systemically before, it was started to be used topically to avoid the adverse reactions such as gastrointestinal tract irritation and hepatitis. Indirubin and indigo are the major active components of indigo naturalis (Lin et al., 2009). After observations of beneficial effects of topically applied indigo naturalis on one child (Lin et al., 2006) and two adult (Lin et al., 2007) patients with severe recalcitrant plaque type psoriasis, a pilot study was conducted to evaluate the efficacy and safety of topical Indigo naturalis in psoriasis (Lin et al., 2007). In this non-randomized, half-side comparison study in 14 patients with chronic plaque psoriasis, significant improvement in clinical scores and histological parameters of proliferation, inflammation and differantiation was reported with indigo naturalis 20% ointment compared with placebo group. One year later, the same research group conducted subsequent randomized, placebo-controlled, observer-blind, intrapatient comparative study with larger number of patients and longer time of period compared to previous one (Lin et al., 2008). They reported significant improvement of lesions in indigo naturalis -treated group compared to placebo (81% vs 26%).
In a small case series of 6 patients (Lin, 2011) and an uncontrolled pilot study of 32 patients with nail psoriasis (Lin et al., 2011), indigo naturalis oil provided a decrease in the Nail Psoriasis Severity Index after 24 weeks and was found to improve nail psoriasis. It was indicated that indirubin inhibits proliferation and abnormal differentiation of epidermal keratinocytes (Lin et al., 2009). Experimental studies also showed that indigo naturalis inhibits neutrophil proinflammatory response and suppress tumor necrosis factor-induced vascular cell adhesion molecule- 1 expression in endothelial cells (Liang et al., 2013). One or combination of them might contribute to the anti-psoriatic effects of indigo naturalis (Lin et al., 2009). Although all of these was reported by same research group, indigo naturalis seems to be promising antipsoriatic agent.
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