Thesis (M.Sc.in Pharm.)--Chulalongkorn University, 2010

Lagerstroemia speciosa L. Pers. (Lythraceae) leaf is used as infusion tea for antidiabetes. Corosolic acid, a triterpene compound, was found in this leaf. In this study, seventeen dried leaves of L. speciosa were collected from natural sources and traditional drugstores for pharmacognostic specifications and setting up the standardization according to Thai Herbal Pharmacopoeia. Anatomical and histological characteristics were the presence of anomocytic stomata and parenchyma containing rosette aggregate crystals of calcium oxalate. The mean contents of loss on drying, moisture content, ash content, acid-insoluble ash were 8.2141, 7.8593, 7.4725, 1.2176% of dry weight respectively. Whereas the ethanol extractive value, water extractive value and dichloromethane extractive value were 9.0280, 13.1895, and 2.9442% w/w, respectively. In addition, chromatographic pattern was investigated. Thin layer chromatographic patterns of methanolic extract were demonstrated. The quantitative analysis by high performance liquid chromatography method using corosolic acid as a marker was also reported. Moreover, this study gave detailed analysis of the DNA fingerprinting of Lagerstroemia. L. speciosa and closely related species, L. macrocarpa, L. floribunda and L. loudinii using the AFLP technique. A species-specific band of L. speciosa was found. All of these results provide highly useful information for the authentication of L. speciosa leaves. It will contribute to effectiveness and safety prior to use