An unusual case of melanosis coli

Review on melanosis coli and anthraquinone-containing traditional Chinese herbs that cause melanosis coli

Backgrounds: The incidence of melanosis coli (MC) has gradually increased annually, attracting significant attention and efforts into this field. A potential risk for MC is the long-term use of anthraquinone laxatives in patients with constipation. Most traditional cathartic drugs are made from herbs containing anthraquinone compounds. This review aims to provide guidance for the application of traditional Chinese herbs containing anthraquinones for physicians and researchers. Materials and methods: We reviewed risk factors and pathogenesis of MC, and natural anthraquinones isolated from TCM herbs. We searched Pubmed and CNKI databases for literature related to MC with keywords such as"traditional Chinese medicine", "Chinese herbs", "anthraquinones", and "melanosis coli". The literature is current to January 2023 when the searches were last completed. After the literature retrieval, the TCM herbs containing anthraquinones (including component identification and anthraquinone content determination) applied in clinical were selected. According to the collected evidence, we provide a list of herbs containing anthraquinones that could cause MC. Results: We identified 20 herbs belonging to 7 families represented by Polygonaceae, Fabaceae, Rhamnaceae, and Rubiaceae, which may play a role in the pathogenesis of MC. Among these, the herbs most commonly used include Dahuang (Rhei Radix et Rhizome), Heshouwu (Radix Polygoni Multiflori), Huzhang (Rhizoma Polygoni Cuspidati), Juemingzi (Semen Cassiae), Luhui (Aloe) and Qiancao (Rubiae Radix et Rhizoma). Conclusion: Due to a lack of awareness of the chemical composition of TCM herbs, many patients with constipation and even some TCM physicians take cathartic herbal remedies containing abundant anthraquinones to relieve defecation disturbances, resulting in long-term dependence on these herbs, which is potentially associated with most cases of MC. When such treatments are prescribed, TCM physicians should avoid long-term use in large doses to reduce their harm on colonic health. Individuals who take healthcare products containing these herbs should also be under the supervision of a doctor.

Melanosis coli: A comprehensive review

Melanosis coli (MC) is a common condition characterized by a black or brown pigment deposited in the colorectal mucosa. It is a reversible condition that is influenced by many factors, such as living habits and bowel function. However, the epidemiology and etiology of MC are still unclear. Most studies show that there is a significant correlation between the use of anthraquinone laxatives and the occurrence of MC. At present, the mechanism of the apoptosis theory is widely recognized as regards the pathogenesis of MC. There is no specific clinical manifestation of MC, and its diagnosis is mainly based on a complimentary examination, such as endoscopic and histopathological tests. General treatment, such as changing living habits, is preferred, and medical or surgical treatment should not be considered in the absence of serious malignancy. The aim of this review is to systematically present and outline the concepts of the epidemiology, etiology, histopathology, pathogenesis, clinical manifestations, diagnosis and treatment of MC, in order to improve the understanding of this condition.

Clinical characteristics of melanosis coli: an analysis of 57 cases

AIM: To investigate the clinical characteristics, etiology and prognosis of melanosis coli (MC).

METHODS: The clinical data for 57 patients diagnosed with MC by colonoscopy were retrospectively analyzed.

RESULTS: From 2006 to 2008, the incidence of MC increased year by year (0.78% < 0.92% < 1.73%). Although no significant difference was noted in the incidence of MC between men and women (P > 0.05), old men and middle-aged women had a higher incidence (P < 0.005). All the patients had a history of taking laxatives. Of all 57 patients, 43 had received an oral administration of anthraquinone laxatives (such as cassia angustifolia, aloe vera capsules, Maren Runchang pills, and Paiduyangyan capsules) for more than 6 years, 12 had taken Guodao Pian for more than 6 years, and 2 had taken weight-loss and slimming tea for 6 to 12 mo; 31 had constipation fewer than three times per week, 21 had difficult defecation, 2 had abdominal pain and bloating, 2 had anal discomfort, 1 had diarrhea and bloody stools, and 1 had colon cancer. Three patients were followed up for 6 to 12 mo after discontinuing use of laxatives, of them 2 showed remission, and 1 recovered.

CONCLUSION: MC is associated with constipation and an extended use of laxatives. Old men and middle-aged women have a higher incidence of MC.

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