This study is a preliminary investigation of the efficacy and safety of T. foenum-graecum (fenugreek) seed extract as add-on treatment in mild asthma. The fenugreek syrup was prepared in honey solution as TPM formula. The aqueous extract of fenugreek seeds improved the lung function tests and Quality of Life in patients with mild asthma significantly in compare with honey and placebo syrup. The use of fenugreek seed extract led to a 10% increase in FEV1 and FEV1/FVC levels, in addition to a significant decrease in serum cytokine IL-4 levels.
Based on few side effects, the study findings suggest that the aqueous extract of fenugreek seeds can be used in mild asthma treatment. To the best of our knowledge, this is the first study to compare fenugreek efficacy with placebo.
Trigonella foenum-graecum was selected among TPM prescriptions [9,10,11]. There are many different formulas in ancient medical textbooks for asthma treatment. We selected a simple combination to observe its effects or side effects more closely during the study.
According to TPM, fenugreek is a lung tonic, and can facilitate lung secretions [9,10,11]. In recent researches, fenugreek is recognized for its antidiabetic [12,13,14,15,16], anti-inflammatory, and antioxidant effects [17,18,19].
Although there is no direct study about fenugreek and asthma treatment, some of its components have been shown to have special efficacy in treatment of asthma. Among the important components are flavonoid; a group of low-molecular-weight polyphenols, which are effective in asthma treatment to some extent. In various studies, fenugreek was found to have antioxidant effects due to the ability of flavonoids to inhibit lipid peroxidation and protect the airways against oxidative stress [28, 29]. Flavonoids also inhibit the activation of basophils and mast cells [17].
Along with the antioxidant effect of fenugreek, quercetin is a flavonoid that can inhibit Charcot–Leyden crystals and eosinophil cationic proteins, which are involved in asthma pathogenesis [30, 31]. It also has ability to reduce the damage caused by oxidative agents [32, 33].
Flavonoids can also inhibit some steps in angiogenesis, such as cell migration and microcapillary tubule formation [34, 35]. As shown in previous studies; vascular changes have an important role in asthma pathogenesis [36].
The anti-inflammatory effects of fenugreek seeds have also been demonstrated [37].
Another possible mechanism of action of fenugreek is due to the mucilage component of seeds (28%), which may facilitate lung secretions and improve asthmatic cough [9,10,11].
Regarding to importance of the relationship between cytokine imbalance (Th1/Th2) in both atopy and asthma expression we selected IL4 as a Th2 profile [38]. In this study IL4 levels significantly decreased after the treatment process in both fenugreek and honey group, of course the effectiveness of fenugreek was more than honey. IL4 divided from T lymphocytes and mast cells could lead to IgE synthesis and airway inflammation [39, 40]. Many studies determined the effect of IL4, IL5 and IL13 in asthma pathogenesis there for making balance between TH1 and TH2 cytokines might be helpful in asthma management [41].
Fenugreek has a wide dose range. In one human study, 25 g of fenugreek seed powder daily was well tolerated and without serious side effects [40]. Acute toxicity values(LD50) documented for fenugreek are 5 g/kg (in rats, oral) and 2 g/kg (in rabbit, dermal) from alcoholic seed extract [42]. The dosage selected in this study was based on PDR for herbal medicine [7].
Despite the effectiveness of fenugreek seeds demonstrated in this study, specific mechanisms for its efficacy remain unknown, and further studies with a larger sample size are needed.
The next important issue in this study was the role of honey. As the results showed, honey syrup could improve the Quality of Life for asthmatic patients, in addition to improving lung function tests and reducing the level of IL-4. Although the effect of honey syrup was less than that of fenugreek syrup in all items, the combination of honey and fenugreek appears to have increased the efficacy of formula.
Many TPM prescriptions use honey as a preservative, but honey also has many benefits in lung diseases [9,10,11]. Recent studies showed the antioxidant effects of honey [43, 44].
However, honey contains flavonoids and can inhibit the growth of certain microbes because of the concentration of sugar and low pH [45, 46]. Research has also shown the anti-inflammatory effects of natural honey [47].
In conclusion the aqueous extract of T. foenum graceum (Fenugreek) in honey based syrup showed acceptable effect in our preliminary study as an add-on treatment in mild asthma.
Due to good results and well tolerance of the fenugreek syrup, this remedy could be suggested as an adjuvant therapy in mild asthma treatment.