The traditional uses, phytochemistry, and pharmacology of Stemona species: A review.

ETHNOPHARMACOLOGICAL RELEVANCE: Plants of genus Stemona (Stemonaceae) have been long used locally and traditionally in many South and East Asian counties to relieve cough, dispel phlegm, prevent asthma, control pests, diminish inflammation, decrease pain, and treat some cutaneous diseases. AIM OF STUDY: This review provided comprehensive and up-to-date information about botanic characterization and distribution, ethnopharmacology, secondary metabolites, pharmacological activities, and toxicology of plants of genus Stemona to explore the scientific potential and future therapeutic potential of the plants. MATERIALS AND METHODS: This article conducted a literature review on information about the Stemona species in multiple electronic databases, including PubMed, Web of Science, Wiley, Science Direct, Elsevier, Google Scholar, ACS publications, SpringerLink, and China National Knowledge Internet. Information was also derived from other literature sources (e.g. Chinese Pharmacopoeia, 2015 edition, Chinese herbal classic books, PhD and MSc thesis). Plant names were validated by "The Plant List" (www.theplantlist.org). All studies of the genus Stemona were included in this review until March 2020. RESULTS: Our comprehensive analysis of the scientific literatures indicated that many Stemona species are popular and valuable herbal medicines with therapeutic potentials to treat various ailments. Phytochemical analyses identified alkaloids and stilbenoids as the major bioactive substances of Stemona species. Numerous studies have shown that the extracts and secondary metabolites isolated from these plants have a wide range of pharmacological activities, including insecticidal and antifeedant, antitussive, anti-inflammatory, anticancer, antimicrobial, and antivirus activities. CONCLUSION: Though plants of genus Stemona have been put to enormous traditional uses, the pharmacological studies conducted were insufficient. Therefore, more secondary metabolites need to be studied for more detailed pharmacological studies. Further studies are also required to establish the mechanisms which mediate the plants' bioactivities in relation to the medicinal uses as well as investigate any potential toxicity for future clinical studies.

Stemona tuberosa prevented inflammation by suppressing the recruitment and the activation of macrophages in vivo and in vitro.

ETHNOPHARMACOLOGICAL RELEVANCE: Stemona tuberosa (ST) is a traditional herbal medicine used for the treatment of various respiratory diseases in eastern Asia. AIM OF THE STUDY: We investigated the anti-inflammatory effects of a ST water extract in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and in cigarette smoke (CS)-induced lung inflammation mouse models. MATERIALS AND METHODS: RAW 264.7 macrophages were treated with the ST extract and stimulated by LPS. The expressions of pro-inflammatory mediators were evaluated by using nitric oxide (NO) assay, enzyme-linked immunosorbent assay and Western blot analysis. After the C57BL/6 mice were exposed to CS, they were administrated with the ST extract. The accumulated inflammatory cells in the bronchoalveolar lavage fluid (BALF) were counted. Also, real-time polymerase chain reaction and hematoxylin and eosin staining were performed in lung tissues. RESULTS: The ST extract treatment reduced the production of NO via blocking the expressions of cyclooxygenase-2 and inducible nitric oxide synthase protein in RAW 264.7 macrophages. In addition, ST extract treatment decreased the secretions of inflammatory cytokines and regulated NF-κB activation by inhibiting the phosphorylation of IκB and the mitogen-activated protein kinase pathway. Also, ST extract administration to mice reduced the infiltrations of macrophages into BALF and the histological inflammatory changes in lung tissues. Furthermore, administration of the ST extract regulated the levels of tumor necrosis factor-α, interleukin (IL)-6, IL-1ß, monocyte chemoattractant protein-1 and matrix metalloproteinases-12 in the lungs. CONCLUSION: These findings suggested that ST extract attenuated pulmonary inflammatory responses by inhibiting the expression of diverse inflammatory mediators in vivo and in vitro.