Evaluating the effect of rice (Oryza sativa L.: SRNC05053-6-2) crude extract on psoriasis using in vitro and in vivo models

Abstract

Psoriasis is mainly caused because of inappropriate immune responses in the epidermis. Rice (Oryza sativa L.: SRNC05053-6-2) consists of anthocyanin, which exhibits strong antioxidative and anti-inflammatory properties. This study aimed to evaluate the role of this black-coloured rice crude extract in alleviating the symptoms of psoriasis using human psoriatic artificial skin and an imiquimod-induced rat psoriasis model. Psoriasis-related genes, cytokines and chemokines were examined; in addition, the antioxidative and anti-inflammatory properties and the immunohistopathological features of this condition were studied. The results showed that the rice extract reduced the severity of psoriasis by (1) decreasing the epidermal thickness, acanthosis, hyperkeratosis, epidermal inflammation and degree of apoptosis induction via caspase-3, (2) increasing the expression levels of anti-inflammatory cytokines (IL-10 and TGF-β), (3) reducing the levels of pro-inflammatory cytokines (IL-6, IL-8, IL-20, IL-22 and TNF-α), chemokines (CCL-20) and anti-microbial peptides (psoriasin and β-defensin), (4) enhancing the antioxidative property (Nrf-2), (5) downregulating the levels of psoriasis-associated genes (psoriasin, β-defensin, koebnerisin 15L and koebnerisin 15S) and (6) upregulating the levels of psoriasis-improving genes (caspase-14, involucrin and filaggrin). Thus, the extract appears to exert therapeutic effects on psoriasis through its antioxidative and immunomodulatory properties.

The Potential of High-Anthocyanin Purple Rice as a Functional Ingredient in Human Health

“…A previous study indicated that the risk of leukemia was reduced after intake of purple rice anthocyanin by increasing the population of white blood cells and promoting macrophage phagocytic activity [ 166 ]. Moreover, the anti-inflammatory properties of anthocyanin extracted from purple rice have been investigated in the treatments of wound healing of psoriasis and oral mucositis in animal models [ 167 , 168 ]. Most recently, anthocyanins isolated from rice husk have been demonstrated to be novel anticarcinogenic compounds in the liver due to their cancer chemo-preventive properties [ 90 ].…”

The therapeutic effects of Bombyx mori sericin on rat skin psoriasis through modulated epidermal immunity and attenuated cell proliferation

“…The rats were shaved on the back (size 3 × 3 cm 2 ) and administered 62.5 mg of imiquimod daily for 7 days to induce psoriasis of the rat skin. 23 , 24 The most effective dose for psoriasis treatment was determined by varying the concentration of sericin treatment and comparing these treatments to the control treatment. For the experiment, the psoriatic rats were divided into six groups (five rats/group).…”

“…The rats in each group were separately treated with Vaseline (nontreated group); 2.5%, 5%, and 10% sericin cream (sericin-treated group); 0.1% betamethasone (positive control for the steroid-treated group); and 3 μg/ml calcitriol ointment (positive control for the vitamin D-treated group). 23 All the treatments were continued 2 times/day for 7 days in combination with 62.5 mg of imiquimod to maintain the psoriatic skin. Then, all the rats were humanely sacrificed by overdose carbon dioxide inhalation.…”

“…Immunostaining was performed as described in our previous report. 23 Briefly, the deparaffinized sections were heat-treated to retrieve the antigens in citrate buffer, pH 6.0. The prepared sections were subjected to immunohistochemical detection using the DAKO EnVision FLEX + peroxidase system for the primary rabbit antibody (Code K8002, DAKO, Denmark).…”

“…In the investigation of an alternative treatment for psoriasis, several studies have examined naturally extracted products, such as crude extracts from Aloe vera , 21 Indigo naturalis , 22 and Oryza sativa , 23 for the treatment of psoriasis. Recently, the extract of B. mori sericin, which has various properties that are beneficial for skin treatment, was used in psoriasis treatment.…”