Wise Mind Herbs

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Viola odorata

Viola is a genus of flowering plants in the family Violaceae, comprising approximately 400-500 species worldwide. The most commonly studied species for medicinal purposes include Viola odorata (sweet violet), Viola tricolor (wild pansy/heartsease), and Viola yedoensis (Chinese violet). These plants have a long history in traditional medicine systems across Europe and Asia.

Common Names and Botanical Classifications

Viola odorata L. is commonly known as sweet violet, English violet, or common violet. Viola tricolor L. is referred to as wild pansy, heartsease, or Johnny-jump-up. Viola yedoensis Makino is known as Chinese violet or Japanese violet. It's important to note that while Viola tricolor and Viola arvensis (field pansy) are sometimes used interchangeably in traditional medicine, they are distinct species with potentially different phytochemical profiles. Similarly, Viola sororia (common blue violet) is sometimes confused with V. odorata but represents a different species native to North America.

Bioactive Compounds

The therapeutic properties of Viola species are attributed to their rich phytochemical profile, which includes flavonoids (rutin, violanthin, quercetin), alkaloids, saponins, anthocyanins, cyclotides, and mucilage. V. odorata is particularly rich in methyl salicylate, while V. tricolor contains significant amounts of viola-quercitrin and rutin. These compounds contribute to the anti-inflammatory, antioxidant, and antimicrobial properties observed in preclinical studies.

Evidence-Based Health Benefits

• Respiratory Conditions: Multiple studies suggest that extracts from V. odorata can help alleviate symptoms of cough, bronchitis, and asthma. V. odorata syrup has been found to significantly reduce cough frequency and severity in children with upper respiratory tract infections compared to placebo.
• Anti-inflammatory Effects: In vitro and animal studies have consistently shown that Viola extracts exhibit anti-inflammatory properties. Cyclotides isolated from V. tricolor demonstrated significant anti-inflammatory activity in a murine model of paw edema.
• Dermatological Applications: V. tricolor extracts have been used to treat various skin conditions including eczema and mild acne. A small clinical trial (n=78) found that a 2% V. tricolor extract cream improved symptoms of mild-to-moderate atopic dermatitis.
• Antimicrobial Activity: Several in vitro studies have demonstrated that Viola extracts possess activity against various bacterial and fungal pathogens. V. odorata extract showed promising activity against multidrug-resistant Staphylococcus aureus.
• Anxiolytic Properties: Preliminary animal studies suggest that V. odorata may have anxiolytic effects. A study using aqueous extract of V. odorata in mice showed significant anxiolytic activity comparable to diazepam at certain doses.
• Anticancer Potential: In vitro studies have shown that certain compounds isolated from Viola species exhibit cytotoxic activity against various cancer cell lines, though clinical studies are lacking.

Recommended Dosages and Standardization

Dosage recommendations vary depending on the preparation and intended use, with limited standardization across studies. For V. odorata syrup in respiratory conditions, 5 ml three times daily (containing approximately 10 mg/ml of total flavonoids calculated as rutin) has been used in clinical studies. For V. tricolor topical preparations, 2-5% extract in creams or ointments applied twice daily has shown efficacy in dermatological applications. Most clinical trials have used extracts standardized to total flavonoid content (typically 2-5% calculated as rutin or quercetin) or total saponin content (1-3%). It should be emphasized that there is insufficient evidence for standardized dosing recommendations across all conditions, and further research is needed to establish optimal therapeutic ranges.

Side Effects and Safety Considerations

• Generally regarded as safe when used at recommended dosages, with few reported adverse effects in clinical trials
• Mild gastrointestinal disturbances (nausea, vomiting) reported in some cases with oral administration
• Allergic reactions possible, particularly in individuals with known allergies to plants in the Violaceae family
• Potential for contact dermatitis with topical preparations in sensitive individuals
• Limited safety data for use during pregnancy and lactation; traditional caution advised
• Theoretical potential for interaction with anticoagulant medications due to the presence of salicylates, though clinical significance is unclear

High-Dose Studies and Knowledge Gaps

There is a notable absence of systematic investigations into doses exceeding the commonly used therapeutic ranges. Animal toxicity studies have indicated that very high doses (>2000 mg/kg of crude extract) may cause hepatotoxicity and nephrotoxicity, though these doses far exceed those used therapeutically. A significant knowledge gap exists regarding the long-term safety and efficacy of Viola preparations, as most clinical trials have been of short duration (typically 2-8 weeks). Additionally, the pharmacokinetics and bioavailability of active compounds from Viola species remain poorly characterized, limiting our understanding of optimal dosing regimens.

Limitations of Current Evidence

Despite promising results from preliminary studies, the overall quality of evidence supporting Viola's medicinal applications remains moderate to low. Many studies suffer from methodological limitations including small sample sizes, inadequate controls, and incomplete reporting of extraction methods or standardization. The heterogeneity in preparation methods and dosages further complicates the interpretation of results across studies. Large-scale, well-designed clinical trials are needed to establish definitive efficacy for specific indications.

Conclusion

Viola species demonstrate promising therapeutic potential across several health conditions, particularly respiratory and dermatological disorders. However, the evidence base consists primarily of preliminary studies and traditional use. While several commercial products incorporating Viola extracts exist, further research is needed to fully characterize the efficacy, optimal dosing, and safety profiles of these botanical medicines. Healthcare practitioners should consider the limited nature of current evidence when recommending Viola-based treatments and monitor for potential adverse effects or interactions.

References

Batiha, G. E. S., Lukman, H. Y., Shaheen, H. M., Wasef, L., Hafiz, A. A., Conte-Junior, C. A., ... & Lawal, B. (2023). A systematic review of phytochemistry, nutritional composition, and pharmacologic application of species of the genus Viola in noncommunicable diseases (NCDs). Evidence‐Based Complementary and Alternative Medicine, 2023(1), 5406039.

Fan, P., Yang, Y., Liu, T., Lu, X., Huang, H., Chen, L., & Kuang, Y. (2021). Anti-atopic effect of Viola yedoensis ethanol extract against 2, 4-dinitrochlorobenzene-induced atopic dermatitis-like skin dysfunction. Journal of Ethnopharmacology, 280, 114474.

Feyzabadi, Z., Jafari, F., Kamali, S. H., Ashayeri, H., Aval, S. B., Esfahani, M. M., & Sadeghpour, O. (2014). Efficacy of Viola odorata in treatment of chronic insomnia. Iranian Red Crescent Medical Journal, 16(12), e17511.

Hellinger, R., Koehbach, J., Fedchuk, H., Sauer, B., Huber, R., Gruber, C. W., & Gründemann, C. (2014). Immunosuppressive activity of an aqueous Viola tricolor herbal extract. Journal of Ethnopharmacology, 151(1), 299-306.

Qasemzadeh, M. J., Sharifi, H., Hamedanian, M., Gharehbeglou, M., Heydari, M., Sardari, M., ... & Minae, M. B. (2015). The effect of Viola odorata flower syrup on the cough of children with asthma: a double-blind, randomized controlled trial. Journal of evidence-b

Saqib, F., Mujahid, K., Aslam, M. A., Modhi, A., Moga, M. A., Bobescu, E., & Marceanu, L. (2020). Ex vivo and in vivo studies of Viola tricolor Linn. as potential cardio protective and hypotensive agent: Inhibition of voltage‐gated Ca++ ion channels. The FASEB Journal, 34(7), 9102-9119.

Zhang, Q., Wang, Q., & Chen, S. (2023). A comprehensive review of phytochemistry, pharmacology and quality control of plants from the genus Viola. Journal of Pharmacy and Pharmacology, 75(1), 1-32.