UHPLC/MS and NMR-Based Metabolomic Analysis of Dried Water Extract of Citrus-Type Crude Drugs

Rapid analysis of bioactive compounds from citrus samples by direct analysis in real-time mass spectrometry combined with chemometrics

Renowned for their nutritional benefits, citrus fruits are harvested at various stages in China for functional food production. This study introduces an innovative analytical method, DART-MS, enabling direct qualitative analysis of citrus samples without the need for preprocessing. Simultaneously, the combination of chemometrics can be applied to distinguish between three different citrus samples: Citri Reticulatae Pericarpium, Citri Reticulatae Pericarpium Viride, and Citri Reticulatae "Chachi". Notably, given the international regulatory concerns surrounding synephrine, a precise quantitative analysis method for synephrine was developed. The limit of detection (LOD) and the limit of quantification (LOQ) were 39 ng mL-1 and 156 ng mL-1, respectively. The recovery rates obtained varied from 98.46% to 100.71%. Furthermore, the intra-day and inter-day precision demonstrated robust consistency, with values spanning 5.0-6.1% and 5.03-6.08%, respectively, offering quicker results compared to those from HPLC-MS, promising a safer assessment of herbal and food products.

Identification strategy of Fructus Gardeniae and its adulterant based on UHPLC/Q-orbitrap-MS and UHPLC-QTRAP-MS/MS combined with PLS regression model

Fructus Gardeniae (FG) is the desiccative and ripe fruits of Gardenia jasminoides Ellis in the Rubiaceae family, which is a commonly used in traditional Chinese medicine (TCM) for clearing away heat, detoxification, relieving restlessness, and eliminating blood stasis. At the same time, it has also been announced as the first batch of TCM with homology of medicine and food. Fructus Gardeniae Grandiflorae (FGG), the fruit of Gardenia jasminoides Ellis var. grandiflora Nakai (Rubiaceae), is a common counterfeit herbal medicine of FG, which still appears in the TCM market, and causes a certain degree of confusion. In order to effectively distinguish FG and its adulterant, the compounds in these two species were thoroughly characterized firstly by ultrahigh-performance liquid chromatography/quadrupole-orbitrap mass spectrometry (UHPLC/Q-Orbitrap MS). Furthermore, a pseudo-targeted metabonomics method with 60 targeted ion pairs was established based on UHPLC-triple quadrupole-linear ion trap mass spectrometry (UHPLC-QTRAP-MS) for discrimination. Multivariate statistical analysis showed that FG and FGG were clustered obviously, and 13 significantly differential markers were screened out by variable importance for projection (VIP) > 1 and p < 0.05 for the construction of the partial least squares (PLS) regression prediction model. The validation of the model proved that its prediction ability was quite satisfactory. Moreover, based on the absolute quantitative analysis of these 13 characteristics, the quality control standards of FG and FFG were established. In summary, an integral method of pseudo-targeted metabonomics combined with chemometrics analysis and a PLS regression model was proposed to provide an effective identification strategy for discrimination FG and FGG.

Dapagliflozin Presented Nonalcoholic Fatty Liver Through Metabolite Extraction and AMPK/NLRP3 Signaling Pathway

In recent years, the incidence rate of nonalcoholic fatty liver disease (NAFLD) has been increasing year by year. The experiments conducted on rat elucidated the effect and underlying mechanism of dapagliflozin in NAFLD. Sprague Dawley rats were fed with HFD (Fat accounts for 52%, carbohydrate 34% and protein 14%) for 12 weeks as NAFLD model. Dapagliflozin presented NAFLD in rat model. Dapagliflozin reduced oxidative stress and inflammation in rat model of NAFLD. Dapagliflozin reduced oxidative stress and inflammation in vitro model of NAFLD. Dapagliflozin in a model of NAFLD metabolized into histamine H1 receptor, caffeine metabolism, mannose type O-glycan biosynthesis, choline metabolism in cancer, tryptophan metabolism, and glycerophospholipid metabolism. Dapagliflozin induced AMPK/NLRP3 signaling pathway. The regulation of AMPK/NLRP3 signaling pathway affected the effects of dapagliflozin on nonalcoholic fatty liver. In summary, dapagliflozin plays a preventative role in NAFLD through metabolite extraction, the inhibition of oxidative stress, and inflammation by AMPK/NLRP3 signaling pathway. Dapagliflozin may be a potential therapeutic agent for oxidative stress and inflammation in model of NAFLD.

Lysine-targeting inhibition of amyloid β oligomerization by a green perilla-derived metastable chalcone in vitro and in vivo

Oligomers of amyloid β (Aβ) represent an early aggregative form that causes neurotoxicity in the pathogenesis of Alzheimer's disease (AD). Thus, preventing Aβ aggregation is important for preventing AD. Despite intensive studies on dietary compounds with anti-aggregation properties, some identified compounds are susceptible to autoxidation and/or hydration upon incubation in water, leaving unanswered issues regarding which active structures in metastable compounds are actually responsible for the inhibition of Aβ aggregation. In this study, we observed the site-specific inhibition of 42-mer Aβ (Aβ42) oligomerization by the green perilla-derived chalcone 2',3'-dihydroxy-4',6'-dimethoxychalcone (DDC), which was converted to its decomposed flavonoids (dDDC, 1-3) via nucleophilic aromatic substitution with water molecules. DDC suppressed Aβ42 fibrillization and slowed the transformation of the β-sheet structure, which is rich in Aβ42 aggregates. To validate the contribution of dDDC to the inhibitory effects of DDC on Aβ42 aggregation, we synthesized 1-3 and identified 3, a catechol-type flavonoid, as one of the active forms of DDC. ¹H-¹⁵N SOFAST-HMQC NMR revealed that 1-3 as well as DDC could interact with residues between His13 and Leu17, which were near the intermolecular β-sheet (Gln15-Ala21). The nucleation in Aβ42 aggregates involves the rate-limiting formation of low-molecular-weight oligomers. The formation of a Schiff base with dDDC at Lys16 and Lys28 in the dimer through autoxidation of dDDC was associated with the suppression of Aβ42 nucleation. Of note, in two AD mouse models using immunoaffinity purification-mass spectrometry, adduct formation between dDDC and brain Aβ was observed in a similar manner as reported in vitro. The present findings unraveled the lysine-targeting inhibitory mechanism of metastable dietary ingredients regarding Aβ oligomerization.

Electrochemical determination of emodin in acidic media by high-performance liquid chromatography and its application to Polygoni Multiflori Radix samples

Electrochemical reduction of emodin under acidic media occurs at a less negative potential when compared with that under neutral media. When emodin is electrochemically detected at a less negative potential, a decrease in background noise and improvement in specificity benefit the development of high-performance liquid chromatography with electrochemical detection (HPLC-ECD) for its determination. HPLC-ECD was performed using an octadecyl silica column, acetonitrile-water (60:40, v/v) containing 5 mmol L^-1 hydrochloric acid and 10 mmol L^-1 lithium perchlorate, as a mobile phase, and an applied potential at - 0.4 V vs. Ag/AgCl. Under these optimal HPLC-ECD conditions, the detection limit (signal-to-noise ratio, S/N = 3) of emodin was 0.61 μg L^-1. When this HPLC-ECD system was applied to the determination of emodin in Polygoni Multiflori Radix (PMR) samples, other peaks did not appear close to the emodin peak on a chromatogram. The emodin contents in PMR samples were determined with relative standard deviations (RSDs, n = 6) of less than 3.9%, and their recoveries ranged from 92 to 106%. We have shown that our HPLC-ECD system performed an accurate, precise, and specific determination of emodin in PMR samples.

Measurement of Naringin from Citrus Fruits by High-Performance Liquid Chromatography - a Review

Naringin is a flavonoid found primarily in citrus species with especially high concentrations being present in grapefruit (Citrus paradisi), bitter orange (Citrus aurantium), and pomelo (Citrus grandis). Because of its many positive effects on human health, naringin has been the focus of increasing attention in recent years. Recently, conventional extraction methods have been commonly replaced with unconventional methods, such as ultrasound-assisted extraction (UAE) and other, more eco-friendly extraction methods requiring little-to-no environmentally harmful solvents or significantly less energy. Naringin analysis is most commonly done via high-performance liquid chromatography (HPLC), and ultrahigh-performance liquid chromatography (UHPLC) coupled with a mass spectrometer (MS) or a photodiode array (DAD) detector. The aim of this review is to provide an overview of recent trends developments in the extraction, sample preparation, and liquid chromatographic analysis of the compound originating from citrus fruits or their products.

Activity-differential search for amyloid-β aggregation inhibitors using LC-MS combined with principal component analysis

Aggregation of amyloid β42 (Aβ42) is one of the hallmarks of Alzheimer's disease (AD). Inhibition of Aβ42 aggregation is thus a promising approach for AD therapy. Kampo medicine has been widely used to combat dementias such as AD. Crude drug known as Shoyaku is an ingredient of Kampo that could have potential as a natural source of novel drugs. However, given that a mixture of compounds, rather than singular compounds, could contribute to the biological functions of crude drug, there are very limited studies on the structure and mechanism of each constituent in crude drug which may have anti-Aβ42 aggregation properties. Herein we provide an efficient method, using LC-MS combined with principal component analysis (PCA), to search for activity-dependent compounds that inhibit Aβ42 aggregation from 46 crude drug extracts originating from 18 plants. Only 5 extracts (Kakou, Kayou, Gusetsu, Rensu, and Renbou) from lotus demonstrated differentially inhibitory activities depending on the part of the plant from which they are derived (e.g. petiole, leaf, root node, stamen, and receptacle, respectively). To compare the anti-aggregative properties of compounds of active crude drug with those of inactive crude drug, these extracts were subjected to LC-MS measurement, followed by PCA. From 12 candidate compounds identified from the analysis, glucuronized and glucosidized quercetin, as well as 6 flavonoids (datiscetin, kaempferol, morin, robinetin, quercetin, and myricitrin), including catechol or flatness moiety suppressed Aβ42 aggregation, whereas curcumol, a sesquiterpene, did not. In conclusion, this study offers a new activity-differential methodology to identify bioactive natural products in crude drugs that inhibit Aβ42 aggregation and that could be applied to future AD therapies.