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

Macroinvertebrate communities in the Big East Lake water network in relation to environmental factors

The Big East Lake water network (BELWN), located in Wuhan city, China, is mainly composed of six lakes and isolated from the Yangtze river. At the background of restoring the hydrological connectivity between rivers and lakes, four season investigations were conducted during 2014–2015 to study the spatial distribution and seasonal dynamics of macroinvertebrate communities, explore their relationships with environmental factors, and forecast the change trends in assemblages in a long period after restoration measures. A total of 40 species were recorded, oligochaetes and chironomids dominated the communities. Season variation in density and biomass were distinct and the community differences in lakes related to the degrees of organic pollution. In comparison with the historical data, the species richness of mollusks in Donghu lake sharply decreased due to water pollution and the loss of diverse habitat. Concerning on the whole BELWN, the whole taxa recorded in our study was slightly fewer than the previous study. A new recorded species polychaete Nephtys sp. was first collected with an important ecological interest. As an urban lake system dominated by eutrophication, the water nutrients significantly affected the distribution of macroinvertebrates. According to the GAM models, the dominant species responded to environmental gradients with different response curves. After restoring the hydrological connectivity between rivers and lakes, the macroinvertebrate communities would change and the biodiversity would steadily increase with time. Additionally, the new recorded species Nephtys sp. would spread into the whole BELWN in the foresee future