Violae Herba: A comprehensive review of the traditional uses, phytochemistry, pharmacology, quality control and clinical applications.

Abstract

Ethnopharmacological relevance: Violae Herba (VH), the dried whole plant of Viola yedonensis Makino that belongs to the family Violaceae, has been long used for treating sores, swollen toxins, carbuncles, erysipelas, and venomous snake bites in China due to is traditional efficacy of clearing heat, detoxifying, cooling blood, and reducing swelling.

Aim of the review: This article aims to report the latest research progress of VH focusing on the ethnopharmacology, phytochemistry, pharmacology, quality control and therapeutic applications, so as to lay a solid foundation for future clinical treatments and scientific studies.

Materials and methods: A comprehensive search was conducted for all Chinese and English literature on "Viola yedoensis Makino" or "Violae Herba" from scientific literature databases including PubMed, CNKI and other literature sources (Ph.D. and M.Sc. dissertations and Chinese herbal classic books), covering the period from January 1955 to August 2024. Subsequently, articles pertaining to classification, historical origins, traditional uses, phytochemistry, contemporary applications, quality control and clinical applications were selected for reference, while literature on growth habits, landscaping and literature appreciation was excluded.

Results: To date, 320 compounds (flavonoids and their glycoside, coumarin, volatile oil, cyclic peptides, alkaloids, terpenoids, organic acids, lignans, etc.) have been isolated and identified from VH. Among which, flavonoids and coumarins are the two major types of constituents that have been taken as the quantitative indicators. Notably, cyclic peptides which exist uncommon in ordinary plants are also effective antibacterial and antitumor constituents in VH. Further pharmacological investigations demonstrate that it exhibits a range of activities, including anti-inflammatory, antibacterial, antiviral, antitumor and immunomodulatory effects. These findings provide a solid theoretical foundation for its application in treating skin diseases, respiratory disorders, digestive system conditions and prospects its potential in clinical uses.

Conclusion: As a widely used herb in TCM formulae, extensive pharmacological and clinical studies have confirmed the traditional efficacy of VH. However, most of the existing studies have focused primarily on its total flavonoids and coumarins, with fewer studies looking at other compounds. This leads to low development and resources waste. Meanwhile, the specific cyclic peptide components with antibacterial and antitumor activity drive us focus on its functional development in the field of medicine and promote the transition from experimentation to clinical practice. Besides, relative limited investigation about its pharmacokinetics and toxicology effects indicates that further systematic studies are needed to ensure the effective and safe application of VH.