Enzyme Inhibitory Activities and RP‐HPLC Analysis of <i>Geranium</i> and <i>Erodium</i> Species

The genera Geranium and Erodium (Geraniaceae) have been documented to possess diverse ethnopharmacological uses, including diabetes mellitus. Relevant to their ethnopharmacological use, the current study aimed to evaluate the α-glucosidase, α-amylase, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) enzyme inhibitory activity of ethanol extracts from 46 samples belonging to thirty-one species of Geranium (20) and Erodium (11) collected throughout Türkiye. The majority of the extracts displayed a marked α-glucosidase and α-amylase inhibitory activity. Besides, 23 extracts out of 46 exhibited a concentration-dependent inhibitory effect over 50 % towards AChE. The highest AChE inhibition was found in G. subcaulescens collected from Konya with an IC₅₀ value of 4.73±2.96 μg/mL. E. somanum, E. leucanthum, and E. sipthorpianum exhibited the most potent α-glucosidase inhibitory activity, while E. birandianum and E. pelargoniiflorum were the most active extracts against AChE and BChE, respectively. Three extracts that had inhibitory activity over 50 % against four of the enzymes were selected and proceeded to RP-HPLC analysis. Geraniin and ellagic acid were identified as major compounds in the active extracts. Most species screened in the current study were examined for the first time against α-glucosidase, α-amylase, AChE, and BChE.