Separation and Qualitative Study of Mentha asiatica Boriss. Essential Oil Components by prep-GC, GC-QTOF-MS, NMR and Prediction of Bioactive Compounds

In order to understand the material basis of wild Mentha asiatica Boris. in Xinjiang, the chemical constituents of essential oil extracted from aerial parts of this plant were studied. A total 52 components were detected and 45 compounds were identified. First of all, the essential oil was separated by silica gel column chromatography, and divided into several parts according to the results of thin layer chromatography. Eight fractions were obtained, and then each fragment was preliminarily screened for antibacterial activity. It was found that all eight fragments had certain antibacterial activity in different level. Then the fractions were subjected to preparative gas chromatography (prep-GC) for further isolation. Ten compounds were identified by ¹³ C-NMR, ¹ H-NMR and gas chromatography-quadrupole time of flight-Mass spectrometry (GC-QTOF-MS). They are sabinene, limonene and β-caryophyllene, (1R*,3S*,5R*)-sabinyl acetate, piperitone oxide, rotundifolone, thymol, piperitone, 4-hydroxypiperiditone, cedrol. After screened by bioautography, 4-hydroxypiperone and thymol were showed best antibacterial activity. The inhibitory effects of the two isolated compounds on Candida albicans and their related mechanisms were studied. The results showed that, 4-hydroxypiperone and thymol significantly reduced ergosterol content on the surface of Candida albicans cell membrane in a dose-dependent manner. This work has accumulated experience for the development and utilization of Xinjiang characteristic medicinal plant resources and new drug research and development, and provided scientific basis and support for the later research and development of Mentha asiatica Boris.

The Suppressive Effect of Mamiran Cream on Atopic Dermatitis-Like Skin Lesions In Vivo

BACKGROUND

The Chinese herbal formula Mamiran cream (MMC) has been known for its ameliorative effects on diverse skin diseases, such as eczema. Atopic dermatitis (AD; eczema) is a chronic recurrent skin disease dominated by T-helper type 2-driven inflammation (Th2).

OBJECTIVE

In this study, the inhibitory effect of MMC on AD was investigated in vivo.

METHODS

An animal model was established by sensitization with 2,4-dinitrochlorobenzene (DNCB) on the skin of SD rats. Cutaneous administration of MMC was applied, and its mechanism of action was investigated via RT-PCR and IHC assay.

RESULT

Our data showed that topical application of MMC reduced the skin severity scores and alleviated the histological changes. Furthermore, immunohistochemical analysis demonstrated that MMC significantly decreased the levels of Th2 cytokine IL-5 and IL-4Ra in the skin lesion. In addition, it was demonstrated that MMC downregulated the mRNA expression of TNF-α, IL-1β, IL-6, IL-10, and TLR4. Moreover, MMC inhibited the activation of NF-κB, JNK1, and STAT6 pathways in skin lesions.

CONCLUSIONS

Our findings suggest that MMC exhibits the inhibitory effect on AD, suggesting that MMC may be a potential therapeutic agent for this atopic disorder.

Diterpenoids from Euphorbia glomerulans with potential reversal activities against P-glycoprotein-mediated multidrug resistance

The development of collateral sensitivity agents that are able to modulate P-glycoprotein (P-gp) is the most promising approaches to overcome multidrug resistance (MDR) in cancer. In this study, eight new diterpenoids of jatrophane and ingenane type, 1-8, and three known ones (9-11) were isolated from Euphorbia glomerulans. Their structures were elucidated by spectroscopic analysis and electronic circular dichroism (ECD) calculations. The MDR reversal activity evaluation of these isolates on breast cancer MCF-7/ADR cells demonstrated the four potent MDR modulators (3, 4, 5, and 9) with great chemoreversal ability and low cytotoxicity. The structure-activity relationship (SAR) analysis indicated that the presence of isobutanoyloxy group at C-8 significantly enhance reversal efficiency. Compound 5 exhibited high efficacy (EC₅₀ = 159.5 nM) in reversing MDR resistance, being stronger than verapamil (EC₅₀ = 302.9 nM). The MDR reversal mechanism assays revealed that 5 could promote the accumulation of Rh123 and DOX in drug-resistant cells in a certain dose-dependent manner, and inhibit P-gp transport function. In addition, the possible recognition mechanism of compound 5 and verapamil (VRP) with P-gp was predicted by molecular docking.

Spectrum-effect relationship between UPLC fingerprints and antidiabetic and antioxidant activities of Rosa rugosa

In this study, the antidiabetic and antioxidant properties of the chemical constituents of Rosa rugosa Thunb. (R. rugosa) was evaluated through analysis of spectrum-effect relationship. The ultra-performance liquid chromatography (UPLC) fingerprints of 21 batches of R. rugosa were evaluated by similarity analysis (SA) and hierarchical clustering analysis (HCA). The 28 common components were identified by ultra-high-performance liquid chromatography coupled to quadrupole-orbitrap high resolution mass spectrometry (UHPLC-Q-orbitrap-HRMS/MS). Meanwhile, the antidiabetic activities and antioxidant activities of 21 batches of R. rugosa were estimated in vitro. Besides, four chemometrics named principal component analysis (PCA), grey correlation analysis (GRA), partial least squares regression (PLSR) and the bivariate correlations analysis (BCA) were applied to construct spectrum-effect relationship between the UPLC fingerprints and biological activities of R. rugosa. The spectrum-effect relationship study revealed that di-O-galloyl-HHDP-glucoside, galloyl-HHDP-glucoside and avicularin were more relevant to antidiabetic activity. Di-O-galloyl-HHDP-glucoside, galloyl-HHDP-glucoside and ellagic acid were the main antioxidant components of R. rugosa. The current bioassay and spectrum-effect relationships are proper for associating sample quality with the active ingredient, and our finding would provide foundation and further understanding of the quality evaluation and quality control of R. rugosa.

Diterpenoid alkaloids from Aconitum barbatum var. puberulum Ledeb

Seven previously undescribed diterpenoid alkaloids, including five C₂₀-diterpenoid alkaloids, barpuberudine, barpubesines A-D, and two C₁₈-diterpenoid alkaloids, barpubenines A-B, along with 11 known diterpenoid alkaloids were isolated from the whole plant of Aconitum barbatum var. puberulum Ledeb. (Ranunculaceae). Barpuberudine is an unprecedented carbon skeleton of C₂₀-diterpenoid alkaloid, while barpubenines A-B are the first example of rearranged types in C₁₈-diterpenoid alkaloids. Their structures were elucidated based on a comprehensive spectroscopic data analysis. The probable pathway of biogenesis of barpuberudine and barpubenines A-B were discussed. Additionally, the antiarrhythmic, cytotoxic and antimicrobial activities of isolates were also evaluated.

Separation and qualitative study of Ruta graveolens L. essential oil components by prep-GC, GC-QTOF-MS and NMR

In order to solve the problem of inaccuracy of using GC-QTOF-MS combined with NIST14 database in analyzing Ruta graveolens L. essential oil components, systematic isolation and characterization of chemicals from essential oil were carried on. Seventeen compounds which were 3 terpenoids, 8 lipid compounds, 3 alcohol compounds and 3 ketones were separated by preparative GC after dividing the essential oil into 5 groups of fractions by silica gel column. The chemical structures of isolated compounds were identified by GC-QTOF-MS and NMR. Three new in general compounds (50, 53 and 55) were isolated. And proton and carbon spectra of six compounds were provided for the first time. Through separation and structure identification of the compounds, qualitative analysis of total chemical components of the essential oil was increased from 42.0% to 90.3%. This research would be of great significance to application of Ruta graveolens L. essential oil.

Identification and quantification of Meiguihua oral solution using liquid chromatography combined with hybrid quadrupole-orbitrap and triple quadrupole mass spectrometers

Meiguihua oral solution (MOS), a classical Chinese medicinal formula, was approved by the China Food and Drug Administration for production. However, the quality evaluation of MOS has not been reported. In this present study, qualitative and quantitative analysis of MOS were conducted by ultra high performance liquid chromatography coupled to quadrupole-orbitrap high resolution mass spectrometry (UHPLC-Q-orbitrap-HRMS) and high performance liquid chromatography-tri-quadrupole linear ion trap mass spectrometry (HPLC-tri-Q-LIT-MS). Totally 46 phenolic compounds (21 flavonoids and 25 tannins) were identified in the MOS, among them 14 polyphenols were not reported in raw plant materials of MOS. The simultaneous quantification of ten compounds including gallic acid, quercetin-3-O-sophoroside, ellagic acid, sophoraflavonoloside, hyperoside, isoquercitrin, avicularin, astragalin, quercitrin and juglanin, which were completed in 16 min in the negative electrospray ionization (ESI) mode under multiple reaction monitoring (MRM) method. Linearity was reached fine determination coefficient (r² > 0.9995). Precisions, repeatability, stability (inter-day and intra-day), and recovery were validated and the relative standard deviations (RSD) were less than 2.9%, 4.7%, 3.6% and 1.79%, respectively. This result proved the high sensitivity and efficiency of the method. The quantitative and qualitative analysis of MOS would provide the substantial basis for further quality control and medicinal values.

Two new glucoside derivatives of truxinic and cinnamic acids from Lavandula angustifolia mill

A phytochemical investigations on the n-butanol fraction of Lavandula angustifolia Mill. residues resulted in the isolation of ten compounds, including two new ones, 4,4'dimethoxy-2,2'di-O-β-d-glucopyranosyl-truxinate (1) and 2-(β-d-glucosyloxy)-trans-cinnamic acid butyl ester (2), along with eight known compounds. The structures of compounds were confirmed by NMR and HR-ESI-MS techniques and comparison with published data. The NMR data for 3 were attributed for the first time. Compound 2 was proofed to be a natural compound in plant rather than a butyl ester artifact formed by esterification reaction with butanol by comparative HPLC-DAD analysis with the ethanol extract which was obtained prior to the application of butanol. All isolated compounds were evaluated for their antioxidant and anti-hypoglycaemic activities. Among them, compounds 4 and 5 showed strong anti-oxidant activities against DPPH with IC₅₀ values of 12.99 and 31.74 μM, respectively. Compound 5 exhibited moderate inhibitory activity against PTP1B with an IC₅₀ value of 31.28 μM.

Jatrophane Diterpenoids from Euphorbia glomerulans

In a phytochemical investigation of the whole plant of Euphorbia glomerulans, 17 new (1-17) and five known jatrophane diterpenoids (18-22) were identified. The X-ray crystallographic data of compounds 1, 4, and 21 permitted the definition of the absolute configurations of these compounds. The cytotoxicity and multidrug resistance reversal activities of the 17 new compounds were evaluated on multidrug-resistant MCF-7/ADR cells overexpressing P-glycoprotein. Several compounds showed different chemoreversal activities and considerably decreased cytotoxicity. Compounds 11 (IC₅₀ value of 5.0 ± 0.8 μM) and 12 (IC₅₀ value of 5.2 ± 2.0 μM) possessed MDR reversal activities that were as good as that of verapamil (IC₅₀ value of 4.7 ± 0.6 μM).

Phenolic glycosides from Lavandual angustifolia

Four new phenolic glycosides (1-4), together with 12 known ones (5-16), were isolated from the essential oil extraction waste of Lavandula angustifolia. Their structures were unequivocally determined by extensive spectroscopic analysis (1D and 2D NMR, HR-ESI-MS, UV, and optical rotation), chemical method, and comparison with data reported in the literature. The antioxidant activities of all compounds and new compounds' influence on melanin content in B16 melanoma cells were examined, which indicated that compounds 1, 8, 13 had a certain degree of DPPH free radical scavenging activities, while only compound 2 could increase the melanin content with a dose-dependent manner.