Camellia sinensis tea melanin suppresses transformation of the aryl hydrocarbon receptor and prevents against dioxin‐induced toxicity in mice

Abstract

The suppressive effects of Camellia sinensis tea melanin (CSTM) on transformation of aryl hydrocarbon receptor (AhR) induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were disclosed for the first time. CSTM strongly inhibited TCDD-induced toxicity with IC 50 equalling 20.4 lg mL )1 . Daily administration of CSTM (40 mg kg )1 , p.o.) prevented TCDD-induced body weight loss, ameliorated TCDD-induced mortality and prevented TCDD-induced hepatomegaly and thymic atrophy. Co-administration of CSTM significantly inhibited TCDD-induced hepatic CYP1 A1 activity. CSTM retarded transformation of AhR in vitro. In animals treated with CSTM, the antibody-secreting cells produced significantly (P < 0.05) more antibodies (32-34%) than the antigen control. Administration of TCDD caused a suppression of antibodyforming cells of 29-33% against the antigen control level. Co-administration of CSTM restored immunity to the control level. We demonstrated that CSTM directly competed with TCDD during the transformation of AhR and suppressed the downstream activation of genes associated with TCDD toxicity.

Assessing the frequency of adverse reactions induced by melanin‐containing formulations used for the management of solar dermatitis

“…Valavanidis et al 4 Mimura et al 5 have shown the anti-inflammatory action of intravenously or intraperitoneally injected melanin in rats. Similar results were obtained by Avramidis et al (1998) 6 who tested the grape melanin as an antiinflammatory agent that modulates the activity of prostaglandins, leukotrienes, and complement system enzymes. In 2016, El-Obeid et al have revealed the anti-inflammatory action of Nigella sativa L melanin suppressing the rat-paw inflammatory edema.…”

Pharmacological Properties of Melanin and its Function in Health

“…Similarly, Avramidis et al . (1998) studied the effect of grape melanin on carrageenan‐induced oedema, as well as on oedemas produced by other phlogistics. They reported that melanin interferes with the prostaglandin, leukotriene and/or other complement systems that mediate inflammation.…”

“…[21] extracted melanin-like pigments (MLPs) from black tea and showed that oral administration of MLPs to mice significantly stimulated splenic lymphoid tissue. Later, Hung et al demonstrated that melanin extracted from different tea species induced cytokine production, with green tea melanin being at least 100 times more active than black tea melanin [30]. They have also reported that antibody-secreting cells produced significantly more antibodies in animals treated with tea melanin (32-34%) than did antigen controls.…”

“…They reported that administration of melanin, by either intravenous or intraperitoneal injection, effectively suppressed the induced subacute and acute inflammation. Similarly, Avramidis et al (1998) [30] studied the effect of grape melanin on carrageenan-induced oedema, as well as on oedemas produced by other phlogistics. They reported that melanin interferes with the prostaglandin, leukotriene and/or other complement systems that mediate inflammation.…”

“…They reported that melanin interferes with the prostaglandin, leukotriene and/or other complement systems that mediate inflammation. They also demonstrated a strong inhibitory effect of grape melanin on suppressing primary inflammation in adjuvant-induced disease in rats [30]. Recently, Nilima et al studied the role of melanin pigmentation in gingival inflammation in pigmented and non-pigmented groups [85].…”