Pharmacognostic analysis and thin-layer chromatographic study of the Thai antipyretic herbal formula Khiao-bencha-khan

Background: Khiao-bencha-khan formula (KBF) is an herbal formula recorded in Thai scriptures and used to treat fever, including exanthematous fever, and aphthous ulcers. It consists of Limnophila rugosa (Roth) Merr., Bacopa monnieri (L.) Wettst., Gossypium arboreum L., Pogostemon cablin (Blanco) Benth., Eupatorium japonicum L., and Justicia gendarussa Burm.f. Objectives: This study aimed to identify the pharmacognostic and chemical profiles of the herbal components found in KBF. Methods: All authentic plant materials were collected, and samples were prepared under Pharmaceutical Inspection Co-operation Scheme/good manufacturing practice guidelines. The materials were identified using macroscopic, microscopic, and thin-layer chromatography (TLC) methods. Results: Microscopic analysis revealed that L. rugosa had distinctively large triangular sunken glandular trichomes and large and short multicellular trichome hairs. G. arboreum had large lysigenous oil reservoirs and stellate trichome hairs. J. gendarussa had lithocyst cells. Glandular trichomes were similarly found in L. rugosa, B. monnieri, G. arboreum, P. cablin, and J. gendarussa. Luteolin was tentatively detected by TLC analysis in KBF and in two of its herbal components, namely, L. rugosa and G. arboreum. Apigenin was not detected in any of the samples. Conclusion: The specifications identified in this study are useful for authenticating and assessing the quality of herbal raw materials, which are essential to ensure good production standards.