Evaluation of Lonicera etrusca var. etrusca Santi (Caprifoliaceae) Stem and Leaf in Terms of Anatomical Structures and Some Phenolic Compounds.

Objectives: The genus Lonicera includes medicinally important plants. Two varieties of L. etrusca have been recorded in Türkiye. Anatomical structures and phytochemical contents are important in the diagnosis and identification of medicinal plants. This study included stem and leaf anatomy of L. etrusca var. etrusca and high performance liquid chromatography (HPLC) analysis of the methanol extracts obtained from these parts.

Materials and methods: Plant materials were collected from Ankara. Methanol extracts were prepared from the stems and leaves by ultrasonic bath. The amounts of chlorogenic acid and caffeic acid that are major compounds in the stem and leaves, were determined by HPLC. For anatomical studies, specimens were preserved in 70% alcohol. Transverse and surface sections were prepared by hand. Detection of tissues was performed using Sartur reagent. Anatomical specimens were examined using a light microscope and microphotographed.

Results: In HPLC analysis, the highest amount of chlorogenic acid was determined in the leaf (1.148%), and the highest amount of caffeic acid (0.156%) was determined in the stem. In the anatomical analysis, it was observed that the stem was disc-shaped and hollow; pericycle is in a ring form, consists of fibre-like cells with thick walls and wide lumina; cork occurs adjoining pericyclic fibers; thin-walled pith cells containing dense druse crystals. The leaf lamina is bifacial in the transverse section; palisade and spongy parenchyma, both contain abundant starch grains; solitary druse crystals are sparse in the leaf mesophyll; the stomata were observed only on the lower surface with 3-5 subsidiary cells. With this study, L. etrusca var. etrusca has been clarified in terms of its anatomical structures and phenolic compounds.

Conclusion: The chemical contents and anatomical structures of the plant may contain important information that can be used in classification. This study may support in taxonomically classification for the L. etrusca var. etrusca.