Comprehensive Evaluation of Deep Eutectic Solvents in Extraction of Bioactive Natural Products

Deep eutectic solvents (DESs) are emerging as green and sustainable solvents for efficient extraction of bioactive compounds or drugs. This work aimed to comprehensively evaluate the potential and effectiveness of DESs for extraction of different types of natural compounds from biomass. Five Chinese herbal medicines including Berberidis Radix, Epimedii Folium, Notoginseng Radix et Rhizoma, Rhei Rhizoma et Radix, and Salviae Miltiorrhizae Radix et Rhizoma were selected to assess the efficiency of DESs on extraction of alkaloids, flavonoids, saponins, anthraquinones, and phenolic acids, respectively. Totally 43 types of choline chloride-, betaine-, and l-proline-based DESs with different polarity, viscosity, composition, and solubilization abilities were tailored to test their extraction efficiency, and the operation conditions were statistically optimized using response surface methodology to produce the most efficient process. In this work, DES solvents were first introduced to extract alkaloids and anthraquinones. The results indicated that most prepared DESs proved to be efficient solvents for extraction of alkaloids, but lower extractability for anthraquinones. The extraction capacity of DES may be correlated with their physical–chemical properties, including H-bonding interactions, polarity, viscosity, and pH. This study demonstrated that DESs were suitable green extraction solvents for selectively and efficiently extracting bioactive compounds from biomaterials

Comparison of Chemical Profiling and Antioxidant Activities of Fruits, Leaves, Branches, and Flowers of <i>Citrus grandis</i> ‘Tomentosa’

<i>Citrus grandis</i> ‘Tomentosa’ (CGT) is particularly cultivated in China and widely used in health foods. In this study, the chemical profiles of different parts of CGT were comprehensively compared by rapid resolution liquid chromatography coupled to electrospray ionization quadrupole time-of-flight mass spectrometry method. A total of 22 compounds were identified and two <i>C</i>-glucosyl flavones were found for the first time in CGT. Four main constituents (rhiofolin, naringin, meranzin hydrate, and isoimperatorin) in different parts of CGT were simultaneously determined. Overall, the contents of the four main compounds decreased with the ripening process. In parallel, the antioxidant activities of their extracts were also evaluated by three assays (2,2′-azinobis­(3-ethylbenzthiazolinesulfonic acid) diammonium salt, 2,2-diphenyl-1-picrylhydrazyl, ferric reducing antioxidant power), and the results indicated a similar tendency: small fruit > flower ∼ medium fruit > large fruit > leaf ∼ branch. The results obtained in the present work may provide useful information for future utilization of CGT

Pulmonary Vascular Hemodynamic data.

<p>Abbreviations: LAp = Left atrial pressure, L/min/m² = Liters per minute per meter squared, PAp = Pulmonary arterial pressure, PAWp = pulmonary artery wedge pressure, PVRI = pulmonary vascular resistance index, QPI = Pulmonary blood flow index, WUm² = Wood Units x meter squared, Note PVRI calculated from pressures at the time of QPI measurement not acoustic recording</p><p>Subjects #1–11 with Pulmonary arterial hypertension (mean pulmonary arterial pressure ≥25 mmHg).</p

Flowcharts for five methods to detect S1 and S2 waves in heart sounds.

<p>(a) Method I, (b) Method II, (c) Method III, (d) Method IV, (e) Method V.</p

Pseudocode of Method V.

<p>The function that detects the first heart sound (S1) and the second heart sound (S2) waves has five inputs: the heart sound signal (HS_signal), event-related durations <i>W</i>₁, <i>W</i>₂, anticipated block width (BlockSize), and the offset (<i>β</i>). Daubechies 'db6' wavelet is used for filtering the signal and the wavelet detail <i>D</i>₆ represents the heart sounds in the analysis.</p

The amino acid sequence of rat chondromodulin-I (rChM-I).

<p>Light gray circles indicate amino acid residues that are not conserved in human ChM-I (hChM-I). Circles in parentheses indicate four amino acid residues that are not conserved in mouse (mChM-I). Four thick bars connecting a pair of Cys residues indicate the intramolecular disulfide bonds, whose arrangements are assumed to be identical with those determined for bChM-I purified from fetal bovine cartilage <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0094239#pone.0094239-Neame1" target="_blank">[27]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0094239#pone.0094239-Hiraki3" target="_blank">[28]</a>. The putative glycosylation sites are also indicated. The arrowhead indicates the determined cleavage site that gives rise to the 14-kDa form of ChM-I.</p

A rigorous optimization over all parameters of Method V: event-related durations <i>W</i>₁, <i>W</i>₂, anticipated block width (BlockSize), and the offset (<i>β</i>).

<p>All possible combinations of parameters (46,376 iterations) have been investigated and sorted in descending order according to their overall accuracy. The data used in this training phase was heart sounds measured at apex for all subjects with mean PAp ≥ 25 mmHg. The overall accuracy is the average value of SE and +P.</p

Features output.

<p>(a) Original heart sound signal from a subject with mean pulmonary arterial pressure of 20 mmHg (b) second-order Shannon energy of <i>D</i>₅ wavelet in Method I (c) second-order Shannon energy of <i>D</i>₆ wavelet in Method II (d) third-order Shannon energy in Method III (e) wavelet approximation <i>A</i>₆ in Method IV (f) generating blocks of interest in Method V.</p

Identification and immunoprecipitation of rat 14-kDa ChM-I.

<p>(A) 8 M urea extracts were prepared from male rat ribs (4-week-old) and subjected to immunoblotting with hCHM-05 ChM-I MoAb. Rat 20–25 kDa glycosylated ChM-I (asterisk) was detected as a broad band as well as a 14-kDa band (thick arrow) and a faint 17-kDa band (arrow). (B) Rat ChM-I extracted in 8 M urea buffer was immunoprecipitated with hCHM-05. Immunoprecipitates were resolved by SDS-PAGE and detected by silver staining. For the specification of immunoprecipitated bands (Ex + Ab), cartilage extracts without the antibody (Ex) or 8 M urea buffer with the antibody (Ab) were similarly processed during the immmunoprecipitation. The asterisk and the arrow indicate 20–25 kDa and 14-kDa ChM-I, respectively. (C) Primary cultures of rat costal chondrocytes were cultured to confluence for 3 days and then conditioned in DMEM/F12 medium in the presence of 10% FBS for the indicated periods of time. The collected conditioned medium was concentrated and subjected to immunoblotting with hCHM-05 ChM-I MoAb.</p

Differential distribution of 14-kDa ΔN-ChM-I and 20–25 kDa ChM-I in mouse developing bone at E16.5.

<p>Frozen sections were prepared from legs of an E16.5 mouse embryo. (A) Toluidine blue (TB) staining of the sagittal section of tibia and fibula. (B, C) Immunofluorescent views of the boxed area in panel A. Double immunofluorescent staining of the sagittal section of proximal tibia with CD31 (red) and N-ChM-I Ab (green; B) or hCHM-05 ChM-I MoAb (green; C). (D) Double immunofluorescent staining of the sagittal section of proximal tibia with N-ChM-I Ab (green) and hCHM-05 ChM-I MoAb (red). (E, F) Absorption test for hCHM-05 ChM-I MoAb is shown. The semiserial sections of tibia was immunostained with hCHM-05 ChM-I MoAb (green) preincubated with BSA (E) or G-rhChM-I (F). In panels D, E, and F, the nuclei were counterstained with DAPI (blue). Asterisks in the panels B-D indicate hypertrophic cartilage zone. Scale bars, 100 μm.</p