Medicinal plants – prophylactic and therapeutic options for gastrointestinal and respiratory diseases in calves and piglets? A systematic review

Ayrle, Hannah; Mevissen, Meike; Kaske, Martin; Nathues, Heiko; Gruetzner, Niels; Melzig, Matthias; Walkenhorst, Michael

The main active compound of medicinally used roots of Glycyrrhiza glabra L. is the saponin glycyrrhizin. Furthermore, it contains flavonoids and isoflavonoids, chalcones, cumarins and phytosterols [123] . With regard to the inclusion criteria of this review, no clinical studies focusing on Glycyrrhiza glabra L. could be found. Nevertheless, it was shown to exhibit immunostimulatory effects in vivo, by stimulation of cellular and nonspecific response [138] . In three in vivo and ex vivo models, antitussive [139] and tracheal smooth muscle relaxing activity [140] as well as regulating effects in the gastrointestinal tract were reported [141] . Four in vitro studies demonstrated its antimicrobial [142, 143] and antiviral potential by activation of autophagy [144] . In an assessment of different plant species, Glycyrrhiza glabra L. exerted the strongest antiviral activity against rotavirus [145] . Due to these versatile effects, Glycyrrhiza glabra L. might be beneficial for prophylaxis and treatment of virus induced diseases of the respiratory-as well as the gastrointestinal tract. Regarding the safety of Glycyrrhiza glabra L., it is important to choose the right dosage due to the hyper-mineralocorticoid-like effects of glycyrrhizin. An acceptable daily dosage of 0.015-0.229 mg glycyrrhizin/kg body weight/day for human and animals was reported [146] .