Efficacy and safety of liquorice extract in asthmatic patients

Abstract

Liquorice is one of the commonly used herbs in the field of medicine due to its pharmacological activities. Among these activities, the anti-inflammatory and antiallergic activities that support its use in asthma. This study included 80 asthmatic patients who were classified into two groups, group 1 (Placebo group) maintained on inhaled corticosteroids (ICs in moderate to high doses) and long-acting beta agonist (LABA) and received starch capsule (500 mg starch) twice daily as placebo and group 2 (active treatment group) maintained on ICs (in moderate to high doses) and LABA and received liquorice extract capsule (500 mg equivalent to 100mg glycyrrhizin) taken twice daily. The efficacy of liquorice was measured by estimation of pulmonary function and blood eosinophils %. On the other hand, safety was assessed by blood pressure measurement and determination of serum potassium level. The results revealed that addition of liquorice capsules to ICs and LABA resulted in a non-significant improvement in blood eosinophils (P-value 0.754). However, it resulted in a highly significant improvement in Forced Vital Capacity (FVC) % and Forced Expiratory Volume1 (FEV1) % when compared to group 1 (P-value 0.031.and 0.040 respectively). Regarding liquorice safety, neither Blood pressure (systolic and Diastolic) (SBP and DBP), nor serum K level showed any significant change in patients received liquorice capsules. Conclusion: liquorice in the used dose significantly improved FVC % and FEV1 % but did not affect blood eosinophils. There was no significant effect on blood pressure and serum K level, so, this dose is safe with no observed side effects.

Efficacy of Persian medicine herbal formulations (capsules and decoction) compared to standard care in patients with COVID‐19, a multicenter open‐labeled, randomized, controlled clinical trial

“…β‐glycyrrhizic acid is a potent anti‐inflammatory compound in licorice that controls inflammation by inhibiting glucocorticoid accumulation and ROS production by neutrophils as strong mediators of tissue inflammation (Parvaiz et al, 2014). In a randomized trial, adding licorice (capsule 500 mg twice daily) to the long‐acting beta‐agonist regimen in chronic stable moderate bronchial asthmatic patients significantly improved Forced Vital Capacity (FVC) % and Forced Expiratory Volume1 (FEV1) (Sadek, Tawfik, Hussein, & Abdelhakeem, 2019). A molecular docking study has demonstrated that glycyrrhizic acid have high binding affinity of −8.0 Kcal/mol and strong inhibitors for M pro of SARS‐CoV2 (Srivastava, Yadav, & Sarkar, 2020).…”

“…Licorice and glycyrrhizin have also been markedly effective against SARS-CoV(Cinatl et al, 2003;Parvaiz et al, 2014), hepatitis C(Miyake et al, 2002) and upper respiratory tract infection(Yanagawa, Ogura, Fujimoto, Shono, & Okuda, 2004).β-glycyrrhizic acid is a potent anti-inflammatory compound in licorice that controls inflammation by inhibiting glucocorticoid accumulation and ROS production by neutrophils as strong mediators of tissue inflammation(Parvaiz et al, 2014). In a randomized trial, adding licorice (capsule 500 mg twice daily) to the long-acting betaagonist regimen in chronic stable moderate bronchial asthmatic patients significantly improved Forced Vital Capacity (FVC) % and Forced Expiratory Volume1 (FEV1)(Sadek, Tawfik, Hussein, & Abdelhakeem, 2019). A molecular docking study has demonstrated that glycyrrhizic acid have high binding affinity of À8.0 Kcal/mol and strong inhibitors for M pro of SARS-CoV2(Srivastava, Yadav, & Sarkar, 2020).Main pharmacological properties of N. sativa and its chemical constituents are antiviral(Salem & Hossain, 2000), anti-inflammatory, immunomodulatory(Forouzanfar, Bazzaz, & Hosseinzadeh, 2014), andF I G U R E1 HPLC chromatograms of ellagic acid (a), emodin (b), glycyrrhizin (c), apigenin (d) thymoquinone (e) in formulations anti-cough (Hosseinzadeh, Eskandari, & Ziaee, 2008) effects.…”

Review on medicinal properties of Glycyrrhiza glabra Linn. (Liquorice)

“…All symptoms usually disappear with discontinuation of therapy. Many studies report no side effects during the course of treatment [31][32] . Generally the onset and severity of symptoms depend on the dose and duration of licorice intake, as well as individual susceptibility.…”

An Updated Comprehensive Review of Plants and Herbal Compounds with Antiasthmatic Effect

“…Chen et al showed the efect of glycyrrhizic acid loaded on PLGA nanoparticles in treating allergic asthma [199]. A clinical study showed that aqueous liquorice extract capsules signifcantly improve pulmonary function tests (increase in FVC% and FEV1%) in asthmatic patients [200].…”