A comparative study of the chemical composition, biological and multivariate analysis of Crotalaria retusa L. stem barks, fruits, and flowers obtained via different extraction protocols

Crotalaria retusa L. (Fabaceae) also known as ‘rattlebox’ has been used in traditional medicine for the management of various human ailments. The present study comparatively evaluated the α-amylase, α-glucosidase, acetylcholinesterase, butyrylcholinesterase, and tyrosinase inhibitory activity, antioxidant properties, as well as phytochemical profiles of extracts of C. retusa (bark, fruits, and flowers) obtained by homogenization, maceration, ultrasonication, and Soxhlet extractions. Little variation was noted between the phytochemical profiles obtained by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) of C. retusa same plant parts extracted by different methods while the different plant parts showed specific phytochemical fingerprints. For instance, myricetin was identified in C. retusa fruits only. Fruit and bark extracts possessed the highest concentrations of quercetin and rutin, respectively. p-hydroxybenzoic acid, a phenolic derivative of benzoic acid, was identified in all C. retusa plant parts. Spectrophotometric determinations revealed that C. retusa bark extracts have highest concentrations of phenolic and flavonoids. Besides, C. retusa bark extracts showed highest antioxidant capacity. The extracts showed high inhibitory activity against α-glucosidase (21.22–4.81 mmol acarbose equivalent/g), acetylcholinesterase (8.71–8.26 mg galantamine equivalent/g), butyrylcholinesterase (4.16–2.36 mg galantamine equivalent/g), and tyrosinase (133.11–125.26 mg kojic acid equivalent/g). Multivariate component analysis showed that the plant part was the main factor responsible for the observed variability between the extracts. Data collected proved that C. retusa has the potential for the development of novel biopharmaceutical, nutraceutical, and cosmetical products.