Rubus caesius L. leaves: Pharmacognostic analysis and the study of hypoglycemic activity

Abstract

Background: Rubus caesius L. is used in traditional medicine, but pharmacological activity data and standardization methods are lacking. Aims and Objectives: This study sought to conduct a pharmacognostic analysis of R. caesius L. leaves and assess these leaves’ hypoglycemic activity. Materials and Methods: External, anatomical, and diagnostic features of the leaves were studied in accordance with the State Pharmacopoeia of the Republic of Belarus T1. Conventional qualitative thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) were used. The hypoglycemic activity of the aqueous extract of the leaves was investigated in an alloxan-induced diabetes model. Results: External, anatomical, and diagnostic features of the leaves were determined. The stomata were anomocytic; calcium oxalate crystals were observed in the mesophyll; stellate-arrayed hairs, star-arrayed hairs, capitate hairs, and simple unicellular hairs with a helical fold were identified. Qualitative results indicated that biologically active substances, such as flavonoids and tannins, were present in R. caesius L. leaves. HPLC and TLC revealed the presence of hyperoside in these leaves. Soundness indicators were defined: The weight loss on drying the R. caesius L. leaves varied from 8.61% to 9.52%, and the average weight loss was 9.1%; determinations of total ash varied from 5.40% to 6.50%; determinations of ash insoluble in hydrochloric acid varied from 0.12% to 0.13%. The hypoglycemic activity of an aqueous extract of R. caesius L. leaves in a 500 mg/kg draught was determined in a rat model of alloxan-induced diabetes. Conclusion: The data obtained here can be used to develop regulatory documentation for a new type of medicinal plant tissue: R. caesius L. leaves.