Simultaneous optimization of ultrasonic-assisted extraction of antioxidant and anticoagulation activities of compounds from Leonurus japonicus Houtt. by response surface methodology

Deep eutectic solvent extraction of myricetin and antioxidant properties

In this study, a response surface method (RSM) was used to optimise the ultrasonic-assisted deep eutectic solvent (DES) extraction of myricetin from myricetin leaves. The results demonstrated that the DES-5 (choline chloride-oxalic acid) system exhibited better extraction results than the other seven DESs prepared. The optimum extraction conditions for myricetin were a DES-5 system with 19% water content of DES, a liquid-to-solid ratio of 37 : 1 mL g-1, an extraction time of 45 min, and an extraction temperature of 72 °C. Under these conditions, the extraction amount of myricetin was 22.47 mg g-1. To optimise the extraction process, the crude myricetin extract was purified, and the optimal conditions were as follows: an AB-8 macroporous adsorption resin was used with an anhydrous ethanol desorption agent. The adsorption rate was 1 BV per h (bed volume per hour), the desorption rate was 1 BV per h, and the desorption capacity was 2 BV (bed volume). The antioxidant properties of the myricetin were also investigated. The results demonstrated that, with an increase in concentration, the scavenging rates of DPPH and ˙OH free radicals increased. Compared to Vc, myricetin had a better scavenging ability for DPPH free radicals, whereas purified myricetin had a better antioxidant effect. At the same concentration, the radical-scavenging rate of the ˙OH radical was slightly higher in myricetin purified by the macroporous adsorption resin than in Vc, and that of the unpurified myricetin was the smallest. Myricetin was purified using a macroporous adsorption resin to improve its antioxidant properties.

Optimization of green deep eutectic solvent (DES) extraction of Chenopodium quinoa Willd. husks saponins by response surface methodology and their antioxidant activities

Quinoa saponins have outstanding activity, and there are an increasing number of extraction methods, but there are few research programs on green preparation technology. The extraction conditions of quinoa saponins with deep eutectic solvents (DESs) were optimized by single-factor experiments combined with response surface methodology. The antioxidant capacity of saponins extracted by DESs and traditional methods was evaluated by the DPPH clearance rate, iron ion chelation rate and potassium ferricyanide reducing power. The results show that the optimal DES is choline chloride: 1,2-propylene glycol (1 : 1), and its water content is 40%. The optimal extraction conditions were as follows: the solid-to-solvent ratio was 0.05 g mL-1, the extraction time was 89 min, and the extraction temperature was 75 °C. Under these conditions, the extraction of quinoa saponins by DES was more effective than the traditional extraction methods. The saponins extracted by DES and traditional methods were analyzed by UPLC-MS, and five main saponins were identified. Quantitative analysis by HPLC-UV showed that Q1 (m/z = 971) and Q2 (m/z = 809) had higher contents of saponins. In vitro antioxidant experiments showed that all DES saponin extracts showed good antioxidant capacity. This study provides new insight into the development and utilization of quinoa saponins.

Optimization of ultrasound-assisted extraction of phenolic content & antioxidant activity of hog plum (Spondias pinnata L. f. kurz) pulp by response surface methodology

Background

The pulp of hog plum (Spondias pinnata L. f. kurz) has been documented as a potential source of nutritional, physiological, and pharmacological purposes due to its phenolic content (TPC) and antioxidant activity. However, an optimal extraction condition for hog plum pulp remains elusive. Optimization of extraction process conditions using Ultrasound-assisted extraction (UAE) technique has recently attracted research interest.

Objectives

The present study focused on optimizing the UAE extraction conditions of TPC and antioxidant activities (DPPH and FRAP) from hog plum pulp by using response surface methodology (RSM).

Methods

The RSM with a three-factor-three-level Box-Behnken design (BBD) was used to optimize the extraction conditions. The BBD was used to investigate the effects of three independent variables, X₁: ultrasonic temperature (40–60 °C), X₂: ultrasonic time (30–60 min), and X₃: ethanol concentration (40–80%) on TPC, DPPH and FRAP assays. Fifteen experimental trials have been carried out to optimize the UAE extraction conditions. A second-order polynomial model was used for predicting the responses. Statistically, the model was validated using an analysis of variance (ANOVA).

Results

The ANOVA results revealed that UAE extraction temperature, time, and ethanol concentration had a significant (p < 0.01) influence on the TPC, DPPH, and FRAP, suggesting that all extraction parameters included in this investigation were crucial to the optimization process. For TPC, DPPH, and FRAP, the R² values were 0.9976, 0.9943, and 0.9989, respectively, indicating that the models developed based on second-order polynomials were satisfactorily accurate for analyzing interactions between parameters (response and independent variables). RSM analysis showed that the optimal extraction parameters which maximized TPC, DPPH, and FRAP were 52.03 °C temperature, 30 min, time, and 79.99% ethanol. Under optimal conditions, experimental values for TPC, DPPH, and FRAP were 370 ± 26 mg GAE/100g DM, 57 ± 7%, and 7650 ± 460 mg AAE/100 g DM, respectively. The experimental values showed a good agreement with the predicted values with residual standard error values below 0.2% under optimum conditions. Pearson's correlation coefficients (r) demonstrate that the TPC showed a weak positive correlation with DPPH (r = 0.3508) and moderate correlation with FRAP (r = 0.3963).

Conclusion

The experimental results agreed with the predicted values, confirming the model's appropriateness and RSM's efficacy in optimizing the UAE extraction conditions. This optimized UAE extraction method may be effective in the industrial extraction process; moreover, further research should be conducted to determine the efficacy of these extracts when applied to food.

Correlation between quality and geographical origins of Leonuri Herba revealed by the qualitative fingerprint profiling and quantitative determination of chemical components

Background

Leonuri Herba (Yimucao) is a very common Chinese herbs for treating menstrual and maternal diseases for thousands of years in China. However, the herb collected in different origins was easily found in the markets which induce the unstable quality for clinic use. In this study, a comprehensive strategy of using multiple chromatographic analysis and chemometric analysis was firstly investigated for chemical discrimination of Leonuri Herba from different geographical origins.

Methods

UHPLC-QTOF-MS/MS was applied to identify the peaks of Leonuri Herba and chemical fingerprints were established in 30 batches from different geographical origins. Meanwhile, dissimilarities of chemical compositions among different origins were further investigated by principal component analysis and cluster analysis. And a quantitative UHPLC-QTOF-MS/MS approach were established to investigate the potential marker for quality control of Leonuri Herba.

Results

A total of 49 chromatographic peaks of Leonuri Herba were identified by UHPLC-QTOF-MS/MS. Leonuri Herba were classified into four categories, and eight major compounds detected could be used as chemical markers for discrimination. Also, the eight components, including leonurine, 4',5-dihydroxy-7-methoxyflavone, rutin, hyperoside, apigenin, quercetin, kaempferol and salicylic acid, were simultaneously quantified using the extracting ion mode of UHPLC-QTOF-MS/MS.

Conclusion

The current strategy not only clearly expounded the correlation between quality and geographical origins of Leonuri Herba, but also provided a fast, accurate and comprehensive qualitative and quantitative method for assessing the quality of Leonuri Herba.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13020-022-00592-w.

Phytochemical Profile and Biological Activities of Crude and Purified Leonurus cardiaca Extracts

Leonurus cardiaca L. (Lamiaceae) is a perennial herb distributed in Asia and Southeastern Europe and has been used in traditional medicine since antiquity for its role against cardiac and gynecological disorders. The polar extracts obtained from L. cardiaca aerial parts contain several compounds among which alkaloids, iridoids, labdane diterpenes, and phenylethanoid glycosides play a major role in conferring protection against the aforementioned diseases. On the other hand, the antioxidant activities and the enzyme inhibitory properties of these extracts have not yet been deeply studied. On the above, in the present study, crude and purified extracts were prepared from the aerial parts of L. cardiaca and have been chemically characterized by spectrophotometric assays and HPLC-DAD-MS analyses. Notably, the content of twelve secondary metabolites, namely phenolic acids (chlorogenic, caffeic, caffeoylmalic and trans-ferulic acids), flavonoids (rutin and quercetin), phenylethanoid glycosides (verbascoside and lavandulifolioside), guanidine pseudoalkaloids (leonurine), iridoids (harpagide), diterpenes (forskolin), and triterpenes (ursolic acid), has been determined. Furthermore, the extracts were tested for their antioxidant capabilities (phosphomolybdenum, DPPH, ABTS, FRAP, CUPRAC, and ferrous chelating assays) and enzyme inhibitory properties against cholinesterase, tyrosinase, amylase, and glucosidase. The purified extracts contained higher phytochemical content than the crude ones, with caffeoylmalic acid and verbascoside as the most abundant compounds. A linear correlation between total phenolics, radical scavenging activity, and reducing power of extracts has been found. Notably, quercetin, caffeic acid, lavandulifolioside, verbascoside, chlorogenic acid, rutin, and ursolic acid influenced the main variations in the bioactivities found in L. cardiaca extracts. Our findings provide further insights into the chemico-biological traits of L. cardiaca and a scientific basis for the development of nutraceuticals and food supplements.

Comparative analysis of the main active constituents from different parts of Leonurus japonicus Houtt. and from different regions in China by ultra-high performance liquid chromatography with triple quadrupole tandem mass spectrometry

A rapid, sensitive and convenient analytical method of ultra-performance liquid chromatography coupled with triple-quadrupole linear ion-trap tandem mass spectrometry (UPLC-QTRAP®/MS²) was proposed for the simultaneous determination of characteristic alkaline and acidic components covering many structure types including alkaloids, phenolic acids, phenylpropanoids and flavonoids in Leonurus japonicus Houtt. (LJ). The proposed method was first reported and validated by assessing the matrix effects, linearity, limit of detections, limit of quantifications, precision, repeatability, stability and recovery of target components. The developed UPLC-QTRAP®/MS² was successfully applied to simultaneously determine all target compounds in 38 batches of LJ from 11 different producing regions in China and five organs (including root, caulis, branch, flower and leaf) of LJ from the same stand planting base in Jiangsu Province (China). The result showed that LJ in different regions with different geographical position would affect the accumulation of different compounds, and the significant discrepancies of some target compounds were also observed in different organs of LJ due to different biosynthetic pathway and enzymes in different organs. Furthermore, both hierarchical clustering analysis and principal components analysis were performed to classify the 38 batches of LJ samples from different producing regions on the basis of target compounds. As a result, the samples could be mainly clustered into different groups, which were similar with areas classification. Overall, the presented method would be helpful for the comprehensive utilization and development of LJ resources.