STANDARDIZATION OF LONICERA JAPONICA FLOWERING BUD AND CONTENTS OF CHLOROGENIC, ROSMARINIC AND CAFFEIC ACIDS IN SELECTED THAI MEDICINAL PLANTS

Abstract

Quantification of chlorogenic, rosmarinic and caffeic acids in 111 selected Thai medicinal plants using high performance liquid chromatography demonstrated that among 111 samples, 39.64% contained all of 3 compounds, 40.54% contained 2 compounds, 14.41% contained only 1 compound and 5.41% could not detect these 3 compounds. Lonicera japonica flowering buds were found to be the richest source for chlorogenic acid content, Melissa officinalis leaves showed the most rosmarinic acid content and the most caffeic acid content was found in Coffea canephora seeds. Pharmacognostic specification and chlorogenic acid content of L. japonica flowering bud from 15 various herbal drugstores throughout Thailand were established. Macroscopic and microscopic evaluation of flowering bud were demonstrated. Physico-chemical parameters including loss on drying, total ash, acid insoluble ash, water content, ethanol and water soluble extractive values were found to be 10.11, 6.59, 1.14, 10.82, 16.46 and 28.88 % by dry weight respectively. For quantitative analysis, chlorogenic acid content in flowering bud by TLC-densitometry compared to TLC-image analysis by imageJ software were found to be 2.24 and 2.09 g/100 g respectively which were not significantly different (P = 0.13). The validation parameters of all quantitative analysis were investigated according to ICH guideline. HPLC as well as TLC-densitometry and TLC-image analysis were demonstrated as suitable, reliable and efficient methods for the quantitative analyses. In vitro biological activities of L. japonica flowering bud compared to chlorogenic, rosmarinic and caffeic acids were evaluated by brine shrimp lethality assay, MTT cell viability assay, comet assay, antimicrobial activities, antioxidant activities and yeast alpha-glucosidase inhibition assay. The results demonstrated that flowering bud ethanolic extract showed non-toxicity on brine shrimp nauplii and 6 tested cell lines. Chlorogenic, rosmarinic and caffeic acids demonstrated toxicity against brine shrimp nauplii. They showed more cytotoxic potentials against tested cell lines than the extract but were still accepted as no cytotoxicity. The extract and 3 compounds showed human lymphocyte DNA damage by comet assay. They were no inhibitory activities against tested microorganisms. The extract and the compounds demonstrated the abilities of DPPH and nitric oxide scavenger and reducing power. However, only the compounds exhibited beta-carotene bleaching activity. Moreover, they inhibited enzyme activity in yeast alpha-glucosidase inhibition study.