Sorghum (Sorghum bicolor L. Moench) contains a XIP-type xylanase inhibitor but none of the TAXI- and TLXI-types

Antitussive, expectorant and bronchodilating effects of ethanol extract of Sorghum bicolor (L.) Moench roots

ETHNOPHARMACOLOGICAL RELEVANCE

Root of Sorghum bicolor (L.) Moench (RSB) is an herbal medicine in Traditional Chinese Medicine, still used in some rural areas in Central China as an alternative remedy to treat cough and asthma.

AIM OF THE STUDY

The study was aimed at evaluating the antitussive, expectorant and bronchodilating effects of ethanol extract of RSB, support its folk use with scientific evidence, and lay a foundation for its further researches.

MATERIALS AND METHODS

RSB was extracted with 80% ethanol aqueous in reflux conditions, solutions were concentrated in reduced pressure, and lyophilized in vacuum to yield the RSB extract. Antitussive evaluations were carried out with three different models including ammonia liquor induced mice cough, capsaicin induced mice cough, and citric acid induced guinea pigs cough; phenol red secretion experiments in mice were performed to evaluate the expectorant ability; bronchodilating effects were evaluated with a bronchoconstrictive challenge induced by acetylcholine chloride and histamine in guinea pigs.

RESULTS

In all the three antitussive tests, treatment of RSB significantly inhibited the frequency of cough, and prolonged the cough latent period in animals. And high dose of RSB (200mg/kg in mice and 100mg/kg in guinea pigs) created therapeutic activities as good as standard antitussive drug codeine phosphate (20mg/kg). In the expectorant evaluation, 50, 100 and 200mg/kg RSB treatment had significantly increased the amount of phenol red output for 0.39, 1.18, and 1.96 folds in mice tracheas. In the bronchodilating test, RSB treatment at 100mg/kg extended the preconvulsive time for 44.84% compared with that of before treatment in guinea pigs.

CONCLUSIONS

RSB is an effective alternative medicine for the treatment of cough with potent antitussive, expectorant and bronchodilating activities.

Algerian pearl millet ( Pennisetum glaucum L.) contains XIP but not TAXI and TLXI type xylanase inhibitors

An XIP (xylanase inhibiting protein) type xylanase inhibitor was purified from Algerian pearl millet ( Pennisetum glaucum L.) grains and characterized for the first time. Cation exchange and affinity chromatography with immobilized Trichoderma longibrachiatum glycoside hydrolase (GH) family 11 xylanase resulted in electrophoretically pure protein with a molecular mass of 27-29 kDa and a pI value of 6.7. The experimentally determined N-terminal amino acid sequence of the purified XIP protein is 87.5%, identical to that of sorghum ( Sorghum bicolor L.) XIP and 79.2% identical to that of wheat ( Triticum aestivum L.) XIP-I. The biochemical properties of pearl millet XIP are comparable to those described earlier for sorghum XIP, except for the higher specific activity toward a T. longibrachiatum GH family 11 xylanase. On the basis of immunoblot neither TAXI nor TLXI type xylanase inhibitors were detected in pearl millet grains.