Pharmacognostic Specification, Chlorogenic Acid Content, and In vitro Antioxidant Activities of Lonicera japonica Flowering Bud

Background: Lonicera japonica Thunb. or Japanese Honeysuckle has been widely used in traditional medicine for antipyretic. Objective: To establish the pharmacognostic specification of L. japonica flowering bud in Thailand and to determine its chlorogenic acid content and in vitro antioxidant activities. Materials and Methods: Dried L. japonica flowering bud from 15 various herbal drugstores throughout Thailand were investigated for pharmacognostic specification. Their chlorogenic acid contents were quantitatively analyzed by thin layer chromatography (TLC) densitometry with winCATS software. The mobile phase for TLC development consisted of ethyl acetate: formic acid: acetic acid: water (10:1.1:1.1:2.6). Antioxidant activities were investigated by 2,2‑diphenyl‑1‑picrylhydrazyl (DPPH) radical scavenging, ferric ion reducing antioxidant power assay, nitric oxide scavenging assay, and β‑carotene bleaching assays. Results: Qualified L. japonica flowering bud in Thailand was presented that the contents of loss on drying, total ash, acid‑insoluble ash, and water should not be >10.11%, 6.59%, 1.14%, and 10.82% by weight, respectively. The ethanol and water soluble extractive values should not be <16.46% and 28.88% by weight, respectively. Chlorogenic acid content in L. japonica flowering bud was found to be 2.24 ± 0.50 g/100 g of crude drug. L. japonica flowering bud showed DPPH and nitric oxide scavenging activities as well as reducing power property. Conclusion: This pharmacognostic specification with special reference to the chlorogenic acid content can be used for quality control of L. japonica flowering bud in Thailand. The potential antioxidant of this crude drug was demonstrated in vitro.