Wonderful Natural Drugs with Surprising Nutritional Values, Rheum Species, Gifts of the Nature

Nutrition therapy on the basis of traditional medicinal plants and herbs is common in many Asian countries, especially Iran and China. Rheum species, especially rhubarbs, belong to plant medicines recognized in 2500 BC. An online search of the literature was carried out at Pubmed/ Medline, Scopus, and Google scholar, covering all years until April 2021. The following key terms were used, usually in combinations: Rheum species, rhubarb, natural products, pharmaceutical benefits, anthraquinones and anthranone. After performing the literature search, the bibliographies of all articles were checked for cross-references that were not found in the search databases. Articles were selected if they reported any biological effects, ethnomedicinal uses, phytochemical compounds and botanical description of Rheum species. The most important components of rhubarb are anthraquinones, anthranone, stilbenes, tannins and butyrophenones. Anthraquinones consist of rhein, emodin, aloe-emodin and chrysophanl, and anthranone includes sennosides and rheinosides. The most important health benefits of rhubarb are antioxidant and anticancer activities, antimicrobial activity, wound healing action, hepatoprotective and anti-diabetic effects, and nephroprotective effect, as well as anti-inflammatory, analgesic and antibacterial activities. Integration of both traditional pharmaceutical science and modern medicines may promote sustainability, lead to organic life and promote the cultivation of medicinal plants.