Sweet Violet (Viola odorata) and Respiratory support: evidence and sources

Ethnopharmacological relevance Severe Acute Respiratory Syndrome (SARS) due to the novel coronavirus has become the highest priority that threatens human health. This situation demands widespread vaccination and the innovation of new therapeutic methods. Despite drug discoveries, the need for approving new medicaments is felt because of adverse effects and lack of efficacy. Several medicinal plants including Viola odorata L. are recommended in traditional Persian medicine for alleviating respiratory infection symptoms. Recent studies showed anti-inflammatory, antioxidant, anti-asthmatic, antitussive, analgesic, and antibacterial activities of sweet violet. These enhance respiratory functions, reduce pulmonary inflammation, and decline mucous membrane edema. This study aimed to evaluate the efficacy of sweet violet syrup in alleviating the manifestations of COVID-19 infection. Material and methods A randomized parallel-group double-blind controlled trial was conducted at Al-Zahra general hospital, Isfahan, Iran. A total of 108 outpatients were enrolled in the study. The patients were randomly allocated to intervention and placebo groups, with 54 patients in each group. The allocation was concealed using sealed opaque envelopes. The intervention group received violet syrup and the control group received placebo syrup, an add-on to the conventional treatment. The outcomes were COVID-19 manifestations, such as dyspnea, cough, myalgia, headache, and diarrhea, considered as outcomes of the study and were evaluated twice using a visual analog scale before the intervention and after 7 days, at the end of the study. Patients were followed daily by phone calls to monitor proper drug consumption and possible side effects. Results No significant difference was between groups regarding demographic characteristics and vital signs before and after the treatment. Although all symptoms have improved significantly in both groups, patients who received violet syrup recovered faster and the mean severity scores of cough (P = 0.025), myalgia (P = 0.036), headache (P = 0.037), and diarrhea (P = 0.044) decreased greater in comparison to control group. Conclusion This study, the first clinical trial on the effectiveness of Viola odorata on SARS-CoV-2 patients, showed that Viola odorata L. effectively controls prevalent manifestations of COVID-19 including cough, myalgia, headache, and diarrhea. Regarding this survey, the violet syrup can be mentioned as a complementary treatment for viral influenza-like infections in which cough, myalgia, headache, and diarrhea are prominent.

This study aimed to investigate the effect of violet syrup on cough alleviation in children with intermittent asthma. In a parallel, double-blind, randomized controlled trial, 182 children aged 2 to 12 years with intermittent asthma were randomly assigned 1:1 to receive violet syrup or placebo along with the common standard treatments in both groups (short-acting β-agonist). Both groups were evaluated in terms of the duration until cough suppression was achieved. No significant difference was observed in basic characteristics. The duration lasting to yield more than 50% cough reduction and 100% cough suppression was significantly less in the violet syrup group compared to placebo (P = .001, P < .001, respectively). There was no significant difference in therapeutic effects between boys and girls. There was a significant inverse correlation between the age of children and rate of cough alleviation and suppression by violet syrup. This study showed that the adjuvant use of violet syrup with short-acting β-agonist can enhance the cough suppression in children with intermittent asthma.