Abstract

Rinorea dentata (Violaceae) is a rare medicinal plant used in treating many diseases such as malaria, neurodegenerative diseases, body inflammation and diabetes among others. The study investigated the in vitro pharmacological activities of crude extract and partitioned fractions from the leaf and stem parts. Antioxidant activity was evaluated using the ability of the crude extract and fractions to scavenge DPPH radical and ferric reducing antioxidant power (FRAP). In vitro anti-inflammatory, anticholinesterase potential of the extracts as well as the inhibition of α-amylase (α-AL) and α-glucosidase (α-GSD) and kinetics of enzymes inhibition were evaluated following standard methods. The ethyl acetate fractions of both leaf and stem gave high total phenolic content and best antioxidant potential in the FRAP assay. For the anticholinesterase activity, crude extract of both leaf and stem had the highest inhibitory activity. Leaf ethyl acetate fraction (34.14±16.69 µgmL-1) had superior LOX inhibitory activity than quercetin (54.75±17.07 µgmL-1) and better than the stem. The dichloromethane fraction had the best α-GSD and mild α-AL inhibitions with 204.00±8.12 and 500.42±2.87 µgmL-1 respective IC50 values. Rinorea dentata leaf extract going by results of the investigation is a good source of antioxidant, anticholinesterase, anti-inflammatory and anti-diabetic agents for future drug development and sustainability.

Key words: Acetylcholinesterase, Anti-hyperglycaemic, Lipoxygenase inhibition, Medicinal application, Rinorea dentata