Biologically Active Iridoids from Hedyotis diffusa

Two new iridoids, 10‐O‐benzoyl‐6′‐O‐α‐L ‐arabino(1→6)‐β‐D ‐glucopyranosylgeniposidic acid ( 1 ), deacetyl‐6‐ethoxyasperulosidic acid methyl ester ( 2 ), along with 14 other known iridoids, were isolated from the whole plant of Hedyotis diffusa Willd. Their structures were determined on the basis of spectroscopic analysis. The short‐term‐memory‐enhancement activities of compounds 1, 7 – 9, 11 , and 13 were evaluated on an Aβ transgenic drosophila model.     

Characterization and identification of iridoid glucosides,flavonoids and anthraquinones in Hedyotis diffusa by high‐performance liquid chromatography/electrospray ionization tandem mass spectrometry

The multiple bioactive constituents in Hedyotis diffusa Willd. (H. diffusa) were extracted and characterized by high‐performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC‐ESI‐MSⁿ). The optimized separation condition was obtained using an Agilent ZorBax SB‐C₁₈ column (4.6×150 mm, 5 μm) and gradient elution with water (containing 0.1% formic acid) and acetonitrile (containing 0.1% formic acid), under which baseline separation for the majority of compounds was achieved. Among the compounds detected, 14 iridoid glucosides, 10 flavonoids, 7 anthraquinones, 1 coumarin and 1 triterpene were unambiguously identified or tentatively characterized based on their retention times and mass spectra in comparison with the data from standards or references. The fragmentation behavior for different types of constituents was also investigated, which could contribute to the elucidation of these constituents in H. diffusa. The present study reveals that even more iridoid glycosides were found in H. diffusa than hitherto assumed. The occurrence of two iridoid glucosides and five flavonoids in particular has not yet been described. This paper marks the first report on the structural characterization of chemical compounds in H. diffusa by a developed HPLC‐ESI‐MSⁿ method.     

A new anthraquinone and eight constituents from Hedyotis caudatifolia Merr. et Metcalf: isolation,purification and structural identification

Hedyotis caudatifolia Merr. et Metcalf. (HC), a folk medicine in Yao nationalities areas in China, was used to investigate the chemical constituents. Through silica gel and Sephadex LH-20 column chromatography, nine compounds were isolated and purified. By physical and chemical properties, IR, MS (EI-MS, high resolution EI-MS), 1D NMR (¹H NMR, ¹³C NMR) and 2D NMR (HSQC, ¹H–¹H COSY, HMBC), their structures were identified as β-sitosterol (1), stigmasterol (2), scopolin (3), 2-hydroxy-1,7,8-trimethoxyanthracene-9,10-dione (4), oleanolic acid (5), ursolic acid (6), methyl barbinervate (7), β-daucosterol (8) and p-Hydroxybenzoic acid (9). These compounds were isolated from HC for the first time, and 4 a new anthraquinone whose biological activities are worth to be investigated in future. These compounds may contribute to the HC’s pharmacological effects on treating diseases, and may be used as candidates for control index in establishing the quality control standard of HC.     

反相高效液相色谱法测定不同产地白花蛇舌草中的对香豆酸

用反相高效液相色谱法对不同产地的白花蛇舌草中对香豆酸的含量进行了测定。色谱柱采用DiamonsilTM ODS柱(4.6 mm i.d.×250 mm, 5 μm),流动相为乙腈-20 mmol/L NH4Ac(pH 4.0)(体积比为15∶85),流速1.0 mL/min,柱温为室温,检测波长为308 nm。在上述条件下测得对香豆酸的质量浓度为4.04～202 mg/L时与色谱峰面积之间线性关系良好(r＝0.9996),高中低浓度条件下的平均回收率为97.4％~102.2%。该方法快速简便,精密度高,重现性和准确度良好,可以作为白花蛇舌草质量控制的一个有效方法。     

Phytochemical profile and bioactivity of traditional ayurvedic decoctions and hydro-alcoholic macerations of Boerhaavia diffusa L. and Curculigo orchioides Gaertn.

Decoctions (DECs) and hydro-alcoholic extracts (HEs) prepared from roots of Boerhaavia diffusa L. (Nyctaginaceae) and Curculigo orchioides Gaertn. (Hypoxidaceae) were phytochemically characterised by HPLC-DAD and profiled for their antioxidant, antigenotoxic and cytotoxic activities. B. diffusa DEC was rich in ferulic acid and vanillin, while the HE also contained boeravinone B and eupalitin. Both C. orchioides HE and DEC displayed the main occurrence of orcinol-β-d-glucoside and curculigoside A. Antioxidant activity was assayed through spectrophotometric DPPH, ABTS and β-carotene bleaching test, and using (HP)TLC bioautographic strategies. For both crude drugs, HE was the best performing preparation. Properly modified SOS-Chromotest evidenced a 10% inhibition by phytocomplexes against 4-nitroquinoline-N-oxide, and a higher bioactivity for vanillin (36.60 ± 1.68%) and ferulic acid (35.09 ± 1.53%). C. orchioides HE was the preparation which showed higher cytotoxicity against drug-sensitive human T-lymphoblastoid cell line (CCRF-CEM) and multidrug-resistant leukaemia cell line (CEM/ADR5000), and eupalitin was the only pure compound to exhibit an IC₅₀ value.     

Solid‐phase Extraction of β‐Sitosterol from Oldenlandia diffusa Using Molecular Imprinting Polymer

The β‐sitosterol imprinted polymer was prepared for selective extraction and analysis of β‐sitosterol from Oldenlandia diffusa (O. diffusa) followed by HPLC with UV detection. The imprinted polymers show high affinity and selectivity to β‐sitosterol. Using this molecularly imprinted polymer (MIP) cartridge as solid‐phase extraction (SPE) material, the interferences could be quickly washed out and β‐sitosterol was selectively retained and enriched. HPLC analysis method was used to evaluate the characteristics of this MIP material. At the condition of mobile phase composed of MeOH/H₂O/H₃PO₄ (99/1/0.1, V/V/V, pH=6.0) and the flow rate of 1.0 mL·min^?1, a good linear relationship was demonstrated when the concentrations of β‐sitosterol were in the range of 0.50–100.0 µg·mL^?1. The recoveries ranged from 75.3% to 86.5% and the inter‐day and intra‐day relative standard deviations were less than 5%. This developed HPLC method was proved to be acceptable for extraction of β‐sitosterol from O. diffusa.     

New Anthraquinone and Iridoid Glycosides from the Stems of Hedyotis hedyotidea

Five new anthraquinone glycosides, hedanthrosides A–E ( 1 – 5 , resp.) and two new iridoid glycosides, hediridosides A and B ( 6 and 7 , resp.), along with two known anthraquinones and four known iridoids, were isolated from the stems of Hedyotis hedyotidea (DC.) Merr . The structures of the new compounds were elucidated on the basis of 1D‐ and 2D‐NMR, and HR‐MS analysis and chemical methods.     

Metabolic effects of Hedyotis diffusa on rats bearing Walker 256 tumor revealed by NMR‐based metabolomics

Hedyotis diffusa, a traditional Chinese herbal medicine, is widely used for oncotherapy and shows a positive effect in the clinical treatment. But its mechanism of anticancer activities is complicated and unclear. This study was undertaken to assess the therapeutic effects and reveal detailed mechanisms of H. diffusa for oncotherapy. A Walker 256 tumor‐bearing rat model was established, and metabolomic profiles of plasma and urine were obtained from ¹H NMR technique. Multivariate statistical analysis methods were used to characterize the discriminating metabolites between control (C), Walker 256 tumor‐bearing rats model (M), and H. diffusa treatment (H) groups. Finally, 13 and 10 metabolomic biomarkers in urine and plasma samples were further identified as characteristic metabolites in M group, whereas H group showed a partial metabolic balance recovered, such as ornithine, N‐acetyl‐l ‐aspartate, l ‐aspartate, and creatinine in urine samples, and acetate, lactate, choline, l ‐glutamine, and 3‐hydroxybutyrate in plasma samples. On the basis of the methods above, we hypothesized H. diffusa treatment reduced the injury caused by Walker 256 tumor and maintained a metabolic balance. Our study demonstrated that this method provided new insights into metabolic alterations in tumor‐bearing biosystems and researching on the effects of H. diffusa on the endogenous metabolism in tumor‐bearing rats.     

Bioassay-Guided Isolation of Anti-Alzheimer Active Components from the Aerial Parts of Hedyotis diffusa and Simultaneous Analysis for Marker Compounds

Previous studies have reported that Hedyotis diffusa Willdenow extract shows various biological activities on cerebropathia, such as neuroprotection and short-term memory enhancement. However, there has been a lack of studies on the inhibitory activity on neurodegenerative diseases such as Alzheimer’s disease (AD) through enzyme assays of H. diffusa. Therefore, H. diffusa extract and fractions were evaluated for their inhibitory effects through assays of enzymes related to AD, including acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), and β-site amyloid precursor protein cleaving enzyme 1 (BACE1), and on the formation of advanced glycation end-product (AGE). In this study, ten bioactive compounds, including nine iridoid glycosides 1–9 and one flavonol glycoside 10, were isolated from the ethyl acetate and n-butanol fractions of H. diffusa using a bioassay-guided approach. Compound 10 was the strongest inhibitor of cholinesterase, BACE1, and the formation of AGEs of all isolated compounds, while compound 5 had the lowest inhibitory activity. Compounds 3, 6, and 9 exhibited better inhibitory activity than other compounds on AChE, and two pairs of diastereomeric iridoid glycoside structures (compounds 4, 8, and 6, 7) showed higher inhibitory activity than others on BChE. In the BACE1 inhibitory assay, compounds 1–3 were good inhibitors, and compound 10 showed higher inhibitory activity than quercetin, the positive control. Moreover, compounds 1 and 3 were stronger inhibitors of the formation of AGE than aminoguanidine (AMG), the positive control. In conclusion, this study is significant since it demonstrated that the potential inhibitory activity of H. diffusa on enzymes related to AD and showed the potential use for further study as a natural medicine for AD treatment on the basis of the bioactive components isolated from H. diffusa.     

Iridoid Glycosides from Hedyotis corymbosa

Three new iridoid glycosides, hedycorysides A–C ( 1 – 3 , resp.), were isolated from the whole plant of Hedyotis corymbosa (Linn .) Lam ., along with four known compounds. Their structures were elucidated by extensive 1D‐ and 2D‐NMR analysis, as well as by HR‐ESI‐MS experiments. The three new compounds are the first benzoylated geniposide derivatives from Hedyotis.