Antihistaminic effect of ''plai'' (zingiber cassummunar roxb.) on histamine skin test in asthmatic children.

ABSTRACT

The rhizome of “Plai” (Zingiber cassummunar Roxb.) has been used as antiasthmatic drug in Thai traditional medicine for a long time. Compound “D” in hexane fraction of “Plai” extract has been shown to inhibit smooth muscle contraction nonspecifically in guinea pig. It also antagonized the action of histamine on bronchial smooth muscle both in vivo and in vitro. Clinical trials of “Plai” have been shown to be effective in asthmatic patients. The purpose of this study is to determine whether usual dose of “Plai” has any antihistamine effect on skin testing. The study was carried out in 24 asthmatic children who had no any medication for 24 hours. There were 13 males and 11 females, age ranged between 8-16 years. Twelve subjects were tested for effect of “Plai” by using intracutaneous test with 0.02 ml of 1 100 histamine solution before and 1ฝ hours after taking 500 mg of “Plai” orally. Diameter of wheal reactions were measured in millimeter. Comparison of wheal size before and after “Plai” was made by statistical analysis and the patients were carefully observed for any side effect. Similar procedures were done in another 12 subjects before and at 1ฝ hours after taking chlorpheniramine (0.1 mg/kg) by month. Comparison in any change of wheal was observed and compared. The results of study revealed that 500 mg. of “Plai” had antihistamine effect. The size of wheal reactions before and after “Plai” had statistical significant difference (P < .005). The size of wheal reactions before and after chlorpheniramine also had statistical significant difference (P < .0005), and reduction of wheal size by “Plai” was lesser than by chlorpheniramine (P < .05). No any adverse reaction was observed during the study.