Ethnobotany, phytochemistry, taxonomy, propagation of the genus Rheum L.: a comprehensive review with emphasis on Central Asia

Abstract

Background: Species of the genus Rheum L. are widely distributed in desert and mountainous regions of China and Central Asia, where they exhibit distinct morphological variations under diverse ecological conditions. Many species of this genus are medicinal plants, whose rhizomes are extensively used in traditional medicine and pharmacology. In Central Asia and some other countries, the leaf petioles are consumed in spring as vegetables rich in vitamins and biologically active compounds. Consequently, numerous studies have been conducted on species of this genus. The present study provides an extensive overview of previously published research on species of the genus Rheum L.

Methods: An extensive online literature search was conducted using major scientific databases, including PubMed, DOAJ, Scopus, and Google Scholar. The following keywords were used, often in combination: Rheum L., Rheum, Latin names of species, rhubarb, traditional medicine, pharmacology, biochemical composition, taxonomy of Rheum L., in vitro, and plantation. In addition, locally published sources on traditional medicine in Uzbekistan, as well as major floristic works, were also consulted.

Results: The results indicate that in China, the rhizomes of Rheum palmatum L., Rheum tanguticum (Maxim. ex Regel) Balf., Rheum officinale Baill., and Rheum rhabarbarum L. have long been valued for their medicinal properties. In Central Asia and some other regions, species such as Rheum maximowiczii Losinsk., Rheum macrocarpum Losinsk., Rheum khorasanicum Baradaran & Jafari, and Rheum ribes L. are consumed in spring by local populations, particularly their leaf petioles growing under stones or in open habitats. Therefore, many biochemical investigations have been conducted on different species of this genus, demonstrating that anthraquinones and related compounds present in the rhizomes represent the major bioactive constituents. Furthermore, extensive research has been conducted on taxonomy, morphology, molecular genetics, in vitro propagation, and plantation establishment. However, several gaps remain in the existing studies, particularly the need for additional taxonomic, morphological, and molecular-genetic investigations. Moreover, studies on chromosomal characteristics, seed germination, and especially the ontogenetic age structure and demographic parameters of populations are insufficient or limited.

Conclusions: In general, representatives of this genus are of significant economic importance due to their medicinal properties. Therefore, further research in the identified priority areas will contribute to a deeper understanding of their biological characteristics and facilitate the conservation of populations by identifying and mitigating potential threats.

Keywords: Rheum L., ethnobotany, medicinal plants, phytochemistry, taxonomy, chloroplast genome, micropropagation, cultivation