Several species within the genera Cassia or Senna have a treasure of traditional medicines worldwide and can be a promising source of bioactive molecules. The objective of the present study was to evaluate the phenolic content and antioxidant and enzyme inhibition activities of leaf methanolic extracts of C. fistula L., C. grandis L., S. alexandrina Mill., and S. italica Mill. The two Cassia spp. contained higher total polyphenolic content (42.23–49.75 mg GAE/g) than the two Senna spp., and C. fistula had significantly (p ˂ 0.05) the highest concentration. On the other hand, the Senna spp. showed higher total flavonoid content (41.47–59.24 mg rutin equivalent per g of extract) than that found in the two Cassia spp., and S. alexandrina significantly (p ˂ 0.05) accumulated the highest amount. HPLC–MS/MS analysis of 38 selected bioactive compounds showed that the majority of compounds were identified in the four species, but with sharp variations in their concentrations. C. fistula was dominated by epicatechin (8928.75 µg/g), C. grandis by kaempferol-3-glucoside (47,360.04 µg/g), while rutin was the major compound in S. italica (17,285.02 µg/g) and S. alexandrina (6381.85). The methanolic extracts of the two Cassia species exerted significantly (p ˂ 0.05) higher antiradical activity, metal reducing capacity, and total antioxidant activity than that recorded from the two Senna species’ methanolic extracts, and C. fistula displayed significantly (p ˂ 0.05) the highest values. C. grandis significantly (p ˂ 0.05) exhibited the highest metal chelating power. The results of the enzyme inhibition activity showed that the four species possessed anti-AChE activity, and the highest value, but not significantly (p ≥ 0.05) different from those obtained by the two Cassia spp., was exerted by S. alexandrina. The Cassia spp. exhibited significantly (p ˂ 0.05) higher anti-BChE and anti-Tyr properties than the Senna spp., and C. grandise revealed significantly (p ˂ 0.05) the highest values. C. grandise revealed significantly (p ˂ 0.05) the highest α- amylase inhibition, while the four species had more or less the same effect against the α-glucosidase enzyme. Multivariate analysis and in silico studies showed that many of the identified phenols may play key roles as antioxidant and enzyme inhibitory properties. Thus, these Cassia and Senna species could be a promising source of natural bioactive agents with beneficial effects for human health.

In this study, six extracts of Arabis carduchorum prepared from solvents of varying polarity (water, methanol, ethyl acetate, dichloromethane, and n-hexane) were investigated for their chemical profiles and total phenolic and flavonoid contents (TPC/TFC) using HPLC–MS/MS and spectrophotometric/colorimetric assays, respectively, along with the assessment of their antioxidant and enzyme inhibitory effects. In general, the polar extracts (methanol, water, and infusion) showed higher TPC/TFC than the other extracts (range: 13.73–26.62 mg GAE/g; 2.66–52.95 mg RE/g, respectively). The total antioxidant capacity of the polar extracts ranged from 0.90–1.85 mmol TE/g in phosphomolybdenum assay, while the free radical scavenging potential ranged from 4.36–32.13 mg TE/g and 12.58–67.73 mg TE/g in DPPH and ABTS assays, respectively. While the water and infuse extract inhibited only butyrylcholinesterase (2.68 and 2.39 mg GALAE/g, respectively), the other extracts were found to inhibit both acetyl- and butyryl-cholinesterases (0.96–2.73 mg GALAE/g and 1.86–5.11 mg GALAE/g, respectively). On the contrary, all extracts exhibited anti-tyrosinase (40.24–59.22 mg KAE/g) and anti-amylase (0.09–0.63 mmol ACAE/g) activities. Overall, this study highlighted the effect of solvent polarity on the extraction of bioactive compounds and the biological properties of the extracts of A. carduchorum; hence, the results obtained could be used to guide optimum extraction in future studies.