PHARMACOGNOSTIC SPECIFICATION AND CHRYSIN CONTENT OF OROXYLUM INDICUM SEED

Abstract

Oroxylum indicum (L.) Kurz, belonging to Bignoniaceae family, is known in Thai common name as Phe-Kaa. In Thailand, it has been used in the treatment of a cough and as a purgative. However, the pharmacognostic specification of this crude drug and its chrysin content have never been established in Thailand. Consequently, this study aimed to exhibit the pharmacognostic specification, analyses of the content of chrysin and fixed oil chemical constituents of O. indicum seeds. O. indicum were collected from 15 different locations in Thailand. The results indicated that the contents of loss on drying, moisture, total ash, acid-insoluble ash, ethanol soluble extractive value and water soluble extractive value were found to be 3.32 ± 0.12, 6.89 ± 0.80, 4.40 ± 0.08, 0.47 ± 0.05, 9.74 ± 0.68 and 12.11 ± 0.80 % by dry weight, respectively. The macroscopic and microscopic characteristics were illustrated in detail. Thin layer chromatographic fingerprints were also established. O. indicum seeds were extracted in 95% ethanol using Soxhlet apparatus. Chrysin of the ethanolic extract was analyzed by thin layer chromatography (TLC) using silica gel 60 GF254 as stationary phase, toluene: chloroform: acetone: formic acid (5:4:1:0.2) as mobile phase, visualization under daylight, UV 254 nm, UV 365 nm and staining with 10 % sulfuric acid reagent. For quantitative analysis of chrysin, the contents in 15 ethanolic extracts were evaluated by TLC-densitometry under UV 269 nm and TLC image analysis under UV 254 nm using image J software which were respectively found to be 0.17 ± 0.05 and 0.20 ± 0.07 % by dry weight. The method validity of TLC-densitometry and TLC image analysis were shown that the calibration range was polynomial with 0.3 – 1.2 µg/spot (R2=0.9998 and R2=0.9998). The accuracy was 109.2 – 109.7 %recovery and 96.7 – 116.0 % recovery. The repeatability was 1.98 ± 0.78%RSD and 3.00 ± 2.23%RSD. The intermediate precision was 4.30 ± 2.24%RSD and 5.12 ± 3.71%RSD. LOD were 0.015 and 0.016 and LOQ were 0.046 and 0.048 µg/spot. The robustness was 2.05%RSD and 4.07%RSD, respectively. Additionally, the fixed oil of O. indicum was extracted in petroleum ether using Soxhlet apparatus. Fatty acid composition of seed oil was analyzed by GC/MS after methylation and 9 components were identified. It was indicated that the main compositions of the fatty acids in O. indicum seed oil are oleic acid (67.99 ± 5.98), palmitic acid (10.22 ± 0.88), behenic acid (7.28 ± 5.60), gondoic acid (5.60 ± 1.28), lignoceric acid (3.11 ± 2.83), linoleic acid (2,69 ± 0.77), stearic acid (1.86 ± 0.42), arachidic acid (1.02 ± 0.31) and 9, 10-dihydroxystearic acid (0.41 ± 0.20) % respectively.