Homogenate-Ultrasound-Assisted Ionic Liquid Extraction of Total Flavonoids from Selaginella involven: Process Optimization, Composition Identification, and Antioxidant Activity

Total biflavonoids extraction from Selaginella chaetoloma utilizing ultrasound-assisted deep eutectic solvent: Optimization of conditions, extraction mechanism, and biological activity in vitro

In this study, the deep eutectic solvent based ultrasound-assisted extraction (DES-UAE) was investigated for the efficient and environmentally friendly extraction of Selaginella chaetoloma total biflavonoids (SCTB). As an extractant for optimization, tetrapropylaminium bromide-1,4-butanediol (Tpr-But) was employed for the first time. 36 DESs were created, with Tpr-But producing the most effective results. Based on response surface methodology (RSM), the greatest extraction rate of SCTB was determined to be 21.68 ± 0.78 mg/g, the molar ratio of HBD to HBA was 3.70:1, the extraction temperature was 57 °C, and the water content of DES was 22 %. In accordance with Fick's second rule, a kinetic model for the extraction of SCTB by DES-UAE has been derived. With correlation coefficients 0.91, the kinetic model of the extraction process was significantly correlated with the general and exponential equations of kinetics, and some important kinetic parameters such as rate constants, energy of activation and raffinate rate were determined. In addition, molecular dynamics simulations were used to study the extraction mechanisms generated by different solvents. Comparing the effect of several extraction methods on S.chaetoloma using ultrasound-assisted extraction and conventional methods, together with SEM examination, revealed that DES-UAE not only saved time but also enhanced SCTB extraction rate by 1.5-3 folds. SCTB demonstrated superior antioxidant activity in three studies in vitro. Furthermore, the extract could suppress the growth of A549, HCT-116, HepG2, and HT-29 cancer cells. Alpha-Glucosidase (AG) inhibition experiment and molecular docking studies suggested that SCTB exhibited strong inhibitory activity against AG and potential hypoglycemic effects. The results of this study indicated that a Tpr-But-based UAE method was suitable for the efficient and environmentally friendly extraction of SCTB, and also shed light on the mechanisms responsible for the increased extraction efficiency, which could aid in the application of S.chaetoloma and provide insight into the extraction mechanism of DES.

Optimization of Extraction of Compound Flavonoids from Chinese Herbal Medicines Based on Quantification Theory and Evaluation of Their Antioxidant Activity

Plant-derived flavonoids have been attracting increasing research interest because of their multiple health promoting effects, where numerous investigations were carried out on the optimization of extraction and bioactivities. This study aims to optimize the extraction process of compound flavonoids (CFs) from Chinese herbal medicines and detect their antioxidant activity in vitro. CFs were extracted from the raw materials named “medicine food homology,” composed of hawthorn, lotus leaf, tartary buckwheat, cassia seed, Lycium barbarum, and Poria cocos in a mass ratio of 4 :  2 :  2 :  1.5 :  1 :  1. L9 (34) orthogonal design, level effect and engineering average estimation, and quantification theory were utilized to improve the extraction method of CFs, and the predictive model for CFs yield was constructed. The 2,2ʹ-diphenyl-1-picrylhydrazyl (DPPH), 2,2ʹ-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), hydroxyl radical scavenging rate, and reducing power of CFs were measured. The highest CFs yield was obtained under the following extraction condition: liquid-solid ratio of 35 : 1 mL/g, extraction temperature of 75°C, extraction duration of 75 min, and extraction mode enzyme-assisted extraction. The forecasted yield was 37.62%. The result was accurate and the established prediction equation was reliable (R = 0.95). The antioxidant activity of CFs was significantly positively correlated with the concentration from 0.05 to 0.4 mg/mL. The DPPH, ABTS, hydroxyl radical scavenging abilities, and the reducing power of CFs were 81.82 ± 1.75%, 49.35 ± 0.09%, 89.78 ± 0.66%, and 0.232 ± 0.001 at the concentration of 0.4 mg/mL, respectively. CFs could be exploited as natural antioxidants in pharmaceuticals and functional foods.

Hepatoprotective and Antioxidant Capacity of Clerodendrum paniculatum Flower Extracts against Carbon Tetrachloride-Induced Hepatotoxicity in Rats

The aim of the presented work involves the isolation, characterization, and evaluation of hepatoprotective potential of Clerodendrum paniculatum flower extracts. For this purpose, petroleum ether, chloroform, ethyl acetate, alcohol, and water extracts of C. paniculatum flower were screened for the flavonoid and phenolic content and quantified. Various antioxidant activity assays including 2,2'-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO) radical scavenging, 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and reducing ability were carried out. Of the above methods, the alcoholic extract exhibited high antioxidant potential and was selected further for the hepatoprotective evaluations. Hepatoprotective evaluation of the alcoholic extract was carried out for carbon tetrachloride (CCl₄)-intoxicated model systems. Enzymes associated with liver functions were estimated, and histopathological evaluations were carried out to monitor the liver architecture. Prominently, reduced levels of various associated enzymes along with increased protein content were observed when the liver specimen was pretreated with the extract. Moreover, the liver architecture was almost comparable to that of the normal control group. The column chromatographic analysis of the extract revealed 13 fractions to possess high phenolics and flavonoid contents. The best two fractions were identified for in vitro hepatoprotective evaluation in the goat liver model. Furthermore, the GC-MS analyses of the fractions were carried out followed by a library search, to identify the constituents responsible for the hepatoprotective activity which revealed the presence of four major constituents-pilocarpine, glyceric acid, pangamic acid, and gallic acid. An in vitro hepatoprotective study of the isolated fractions showed better activity compared to the whole alcoholic extract, and the results were comparable to the normal group taken as a control. The investigations with an in vitro model suggest that the isolated fraction with rich flavonoid content showed better hepatoprotective activity. GC-MS analysis of the fractions that displayed good hepatoprotective activity suggested the presence of pilocarpine, glyceric acid, pangamic acid, and gallic acid, while HPTLC analysis revealed the presence of quercetin.