Diabetes mellitus (DM) is one of the globally worst killer diseases. In this study, the in vitro and in vivo antidiabetic activity and antioxidant capacity were determined and the phytochemical analyses were carried out on flower extract and sub-extracts of Rhaponticoides iconiensis. The in vitro antidiabetic activity was tested with α-amylase and α-glucosidase enzyme inhibition methods and an in vivo OGTT test in healthy and alloxan-induced rats. Although, the antioxidant activity was investigated with DPPH^●, ABTS^●+ and FRAP tests, the phytochemical composition analysis was carried out by LC-MS/MS. The highest α-glucosidase and α-amylase activity even from positive control acarbose were found in the ethyl acetate sub-extract of R. iconiensis (IC₅₀ = 11.737 ± 0.823 µg/mL and 84.247 ± 0.721 µg/mL, respectively). This sub-extract also was active according to the results of in vivo tests. Moreover, the highest antioxidant activity on DPPH^● (IC₅₀ = 0.126 ± 0.002 mg/mL), FRAP (at a concentration of 1 mg/mL equivalent to 3112.052 ± 2.023 mmol Fe²⁺) and ABTS^+● (at a concentration of 0.5 mg/mL equivalent to 0.608 ± 0.005 µM Trolox) tests. In addition, LC-MS/MS analyses of the active sub-extract revealed mainly the presence of patuletin, patuletin 3,7-diglucoside, naringin and 3,4-dicaffeoylquinic acid detected in the active sub-extract. In silico molecular docking and dynamics simulations studies were performed on these compounds with α-amylase and α-glucosidase enzymes for protein–ligand interactions and stability.

The enzyme-assisted approaches for plant phenolics extraction are more eco-friendly methods compared to acid or alkaline hydrolysis. Carbohydrase enzymes can release free phenolics from plant materials by cleaving the glycosidic bonds between phenolic compounds and cell wall polymers. In this study, the efficiency of carbohydrase-assisted treatment approaches was evaluated to extract bioactive phenolics from hawthorn (Crataegus orientalis) fruit residues. Enzymatic treatment of the fruits was operated by using a crude cellulolytic enzyme cocktail from Rhizomucor miehei NRRL 5282 and a pectinase preparate from Aspergillus niger. Both cellulase and combined cellulase–pectinase treatments improved the total phenolic content (TPC) and antioxidant activity of extracts. The TPC increased to 1899 ± 27 mg gallic acid equivalents/100 g dry matter during the combined enzyme treatment, showing a strong correlation with the average antioxidant capacity determined by ferric-reducing antioxidant power (1.7-fold increment) and 2,2-diphenyl-1-picrylhydrazyl (1.15-fold increment) reagents. The major phenolics in enzyme-treated extracts were vanillic and ferulic acids, the concentrations of which increased 115.6-fold and 93.9-fold, respectively, during carbohydrase treatment. The planktonic growth of Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, and Chromobacterium violaceum was slightly inhibited by the extracts with minimum inhibitory concentration values between 15.0 and 77.9 mg/mL, while the yeasts tested were quite resistant to the samples. B. subtilis and yeast biofilms were sensitive to the enzyme-treated extracts, which also showed quorum-sensing inhibitory effects against C. violaceum. The obtained bioactive hawthorn extracts hold potential as a natural source of antioxidants and antimicrobials.

Scutellaria species are widely utilized and have demonstrated diverse biological effects for various diseases, both globally and in traditional Chinese medicine, due to the presence of bioactive compounds with unique structures. This study was conducted to reveal the in vitro effects and phytochemical properties of Scutellaria salviifolia Benth., an endemic species of Türkiye. The inhibitory effects of methanol extracts prepared separately from the aerial and root parts of S. salviifolia on the COX-2 and 5-LOX enzymes and their DPPH and ABTS radical scavenging activities were evaluated using in vitro methods. Additionally, the phenolic compounds of the extracts were compared based on Q-TOF LC/MS analysis. The extracts of S. salviifolia exhibited a high inhibitory effect on COX-2 enzyme activity, comparable to that of celecoxib. Still, they showed no significant effects in the 5-LOX enzyme inhibition assay. In the antioxidant activity assays, the percentage of inhibitory effects of both extracts against DPPH and ABTS were similar. A total of 29 and 27 compounds were detected in the aerial part and root extracts, respectively. Among the identified compounds, 18 were common to both the aerial part and root extracts. S. salviifolia may serve as a valuable alternative to the most well-known Scutellaria species, including S. baicalensis and S. barbata.

Cousinia is one of the widespread genera of Asteraceae family. This study aims to evaluate the biological activities and phytochemical compositions of C. iconica extracts. The antioxidant effects of the extracts were investigated on DPPH^•, ABTS^+•, and iron chelating methods, and the inhibition effects were tested on α-amylase, α-glucosidase, and tyrosinase, as well as AChE, and BChE enzymes. The quantitative and qualitative determinations of the compounds of the extracts were carried out by LC-MS/MS. As a result, the highest TPC (271.65 ± 3.32 mg GAE/g_extract), and TFC (4.79 ± 0.06 mg QE/g_extract) were found in C. iconica ethyl acetate (CIE) sub-extract. The highest antioxidant activity on DPPH^• (IC₅₀ = 90.397 ± 0.575 µg/mL) was shown in C. iconica methanol (CIM) extract. The highest ABTS^+•, and iron chelating activities were found in CIE with IC₅₀ = 70.70 ± 0.38, and 615.10 ± 2.47 µg/mL, respectively. The highest α-amylase, and tyrosinase activities were found in CIE, and C. iconica n-butanol sub-extract (CIB) with 864.57 ± 0.68, and 475.21 ± 6.22 µg/mL IC₅₀ values, respectively. AChE, and BChE activities were observed as the highest in CIB (IC₅₀ = 426.50 ± 3.78 µg/mL), and CIM (IC₅₀ = 330.54 ± 0.79 µg/mL), respectively. According to LC-MS/MS analyses, rutin, and cynarin were determined as the main constituents of CIM, and CIE. This is the first report that these biological activities and phytochemical compositions of C. iconica were investigated.