Chemical Constituents of the Rhizomes of Bletilla formosana and Their Potential Anti-inflammatory Activity

Bioactive phytochemicals from the tubers of Bletilla striata Rchb.f

Thirty-four phytochemicals were isolated from dry tubers of Bletilla striata Rchb.f. The compounds were classified as bibenzyls 1-14, dihydrophenanthrenes 15, 17, 20, 21, phenanthrenes 16, 18, 19, simple benzoids 22-24, a fatty acid 25, glucosyloxybenzyl 2-isobutylmalates 26-32, and glucosyloxybenzyl cinnamates 33, 34. Compounds 1-4, 7, 8, 11, 12, and 16 inhibited melanogenesis (17.96-55.27%) induced by α-MSH in B16F10 cells at 10-40 μM. However, compounds 9, 10, 17, 18, and 21 exhibited significant cytotoxicity against melanomas, with IC50 values of 12-34 μM. Additionally, compounds 15, 17, 19, 20, 23, 31, and 33 reduced the ROS generation induced by H2O2 in HaCaT cells at 6.25-100 μM. In particular, compounds 15, 19, and 20 strongly inhibited ROS generation, with IC50 values of 2.15-9.48 μM. Consequently, compounds 1-4, 7-12, and 15-21 may be the strongest leads to follow in B. striata extract for further research on the skin disorders, hyperpigmentation, melanoma, and ageing.

Harzianic acids and oxazolidinone from the endophytic fungus Ilyonectria sp. and their cytotoxicity activity

Four undescribed compounds including three harzianic acids (1, 3 and 4) and one oxazolidinone (2), along with three known ones (5-7) were isolated from the solid fermented product of endophytic fungus Ilyonectria sp., their structures were elucidated as 1-amino-harzianic acid (1), ilyonectria-oxazolidinone (2),10'-nor- isoharzianic acid (3), isohomoharzianic acid (4), harzianic acid (5), isoharzianic acid (6), homoharzianic acid (7) by means of detailed chemical evidences and spectroscopic data analysis. All the compounds were evaluated for cytotoxicity against SMMC-7721 human cancer cell lines by MTS assay. Among the seven tested compounds, 1-amino-harzianic acid (1) demonstrated well cytotoxic activity against SMMC-7721 with IC50 value of 26.84 μM. The results of molecular docking indicated that compound exhibited moderate anti-tumor activity may through binding to apoptosis related proteins.

Dihydrophenanthro[b]furan derivatives from the tubers of Bletilla striata

Two pairs of new dihydrophenanthro[b]furan enantiomers blephebibnols G-H (1-2), one new dihydrophenanthro[b]furan derivative blephebibnol I (3), along with four known analogues (4-7), were isolated from the tubers of Bletilla striata. Their structures including the absolute configurations were determined by the combination of spectroscopic data analysis, ECD and NMR calculations. Compounds 1a, 1b, and 2b showed inhibition of NO production in LPS-stimulated BV-2 cells, with IC50 values ranging from 4.11 to 14.65 μM. Further mechanistic study revealed that 1a suppressed the phosphorylation of p65 subunit to regulate the NF-κB signaling pathway. In addition, some compounds displayed selective cytotoxic activities against HCT-116, HepG2, A549, or HGC27 cancer cell lines with IC50 values ranging from 0.1 to 8.23 μM.

Dimeric phenanthrenoids: possible biogenetic pathway and missing compounds

Secondary metabolites extracted from plants have historically been critical for drug discovery, but their isolation involves expensive and complicated procedures in terms of time and labor resources. Thus, the biogenetic pathway offers the possibility of identifying specific compounds that have not yet been isolated and predicting their isolation from specific natural sources. In plants, biphenanthrenes represent a relatively small group of aromatic secondary metabolites that are considered as important taxonomic markers with promising biological activities. To date, 38 mixed phenanthrenoid dimers have been identified, the biosynthesis of which involves the radical coupling of the two subunits, namely, a phenanthrene and a dihydrophenanthrene. For each of the compounds, it is possible to identify the single phenanthrenic and dihydrophenanthrenic units constituting the considered dimer. Based on the biogenetic pathway, it is possible to identify 19 phenanthrenes and 17 dihydrophenanthrenes, and to distinguish those already known from those not yet isolated. By comparing the results of the possible biosynthetic pathway for each compound with the data in the literature, it is possible to identify three known phenanthrenes and seven known dihydrophenanthrenes, as well as eleven new phenanthrenes and five new dihydrophenanthrenes, and to identify from which plant it is possible to isolate them. This could direct the work of researchers seeking to identify known or new molecules useful for their possible biological properties, and ultimately, to confirm the veracity of the proposed and generally accepted biosynthetic pathway.

Dihydrophenanthrene Dimers: Why and Where It Is Possible to Isolate Their Precursors

An interesting class of compounds of natural origin is dihydrophenanthrene dimers, which are characterized by a series of remarkable biological properties. Considering the hypothesis that each dimer is obtained through a biosynthetic mechanism that involves the coupling of the corresponding radicals of the single dihydrophenanthrene unit, we identified 29 dihydrophenanthrenes. Of these dihydrophenanthrenes, 11 were new compounds that could be isolated from 10 different plant species; 11 had already been identified, but not yet isolated in the 17 different plant species from which the corresponding dimers had been isolated; and 7 were known and had been isolated in the same plant sources of the corresponding dimers. A targeted analysis of several natural extracts from specific plant sources would allow the identification of known or new molecules with potential and/or specific biological activities and, in a final analysis, would confirm the relative biosynthetic mechanism.

Xylochemical Synthesis and Biological Evaluation of the Orchidaceous Natural Products Isoarundinin I, Bleochrin F, Blestanol K, and Pleionol

The first total syntheses of the orchid-derived natural products isoarundinin I (1), (±)-bleochrin F ((±)-2), (±)-blestanol K ((±)-3), and (±)-pleionol ((±)-4) from renewable starting materials are reported, along with the evaluation of their biological activities. The total syntheses were based on regioselective aromatic bromination reactions in combination with a key acid-promoted regioselective intramolecular cyclization. The biological results suggest that isoarundinin I (1), (±)-blestanol K ((±)-3), and (±)-pleionol ((±)-4) have the potential to inhibit the growth of both sensitive and multidrug-resistant cancer cells.

Lung protective effects of dietary malate esters derivatives from Bletilla striata against SiO2 nanoparticles through activation of Nrf2 pathway

Objective

To study the protective activities of the dietary malate esters derivatives of Bletilla striata against SiO₂ nanoparticles-induced A549 cell lines and its mechanism action.

Methods

The components were isolated and elucidated by spectroscopic methods such as 1D NMR and 2D NMR. And MTT assays was used to tested these components on the A549 cell survival rates and ROS or proteins levels were detected by Western blotting.

Results

A new glucosyloxybenzyl 2-isobutylmalate (a malate ester derivative), along with 31 known compounds were isolated and identified from n-BuOH extract of EtOH extract of B. striata. Among them, compounds 3, 4, 11, 12 and 13 possessed noteworthy proliferative effects for damaged cells, with ED₅₀ of 14.0, 13.1, 3.7, 11.6 and 11.5 µmol/L, respectively, compared to positive control resveratrol (ED₅₀, 14.7 µmol/L). Militarine (8) prominently inhibited the intracellular ROS level, and increased the expression of Nrf2 and its downstream genes (HO-1 and γ-GCSc). Furthermore, Nrf2 activation mediates the interventional effects of compound 8 against SiO₂ nanoparticles (nm SiO₂)-induced lung injury. Moreover, treatment with compound 8 significantly reduced lung inflammation and oxidative stress in nm SiO₂-instilled mice. Molecular docking experiment suggested that 8 bound stably to the HO-1 protein by hydrogen bond interactions.

Conclusion

The dietary malate esters derivatives of B. striata could significantly increase the viability of nm SiO₂-induced A549 cells and decrease the finer particles-induced cell damages. Militarine is especially promising compound for chemoprevention of lung cancer induced by nm SiO₂ through activation of Nrf2 pathway.

The structures of two glucomannans from Bletilla formosana and their protective effect on inflammation via inhibiting NF-κB pathway

Bletilla formosana is a traditional Chinese herbal medicine and is widely consumed as foods and medicines in China. However, the chemical structure and bioactivity of its polysaccharides remain unknown. Herein, two new polysaccharides, BFP60 and BFP80, with molecular weights of 3.99 kDa and 10.07 kDa, respectively, were isolated and purified from dried tuber of B. formosana. Structural analysis suggested that BFP60 and BFP80 may have backbone consisted of →4)-β-d-Man-(1→,→4)-β-d-Glc-(1→,→4)-2-O-acetyl-β-d-Man-(1→, and →4)-3-O-acetyl-β-d-Man-(1→. Inflammation assay in LPS-induced RAW264.7 cells showed that the productions of NO and pro-inflammatory cytokines including IL-6, IL-1β, TNF-α, and IFN-γ were significantly reduced, and the expression of iNOS, COX-2, and target proteins in the NF-κB pathway were suppressed after BFP60 and BFP80 pretreatment. These findings indicated that this novel polysaccharide had significant inflammatory protective effects in vitro.

Biological evaluation, molecular modeling and dynamics simulation of phenanthrenes isolated from Bletilla striata as butyrylcholinesterase inhibitors

As part of our continuous studies on natural cholinesterase inhibitors from plant kingdom, the 95% ethanol extract from tubers of Bletillastriata showed promising butyrylcholinesterase (BChE) inhibition (IC₅₀ = 8.6 μg/mL). The extracts with different polarities (petroleum ether, ethyl acetate, n-butanol, and water) were prepared and evaluated for their inhibition of cholinesterases. The most active ethyl acetate extract was subjected to a bioassay-guided isolation and afforded twenty-two bibenzyls and phenanthrenes (1–22). All isolates were further evaluated for their BChE inhibition activity, and five phenanthrenes presented promising capacity (IC₅₀ < 10 μM). Further kinetic studies indicated their modes of inhibition. Compounds 6, 8, and 14 were found to be mixed-type inhibitors, while compounds 10 and 12 could be classified as non-competitive inhibitors. The potential interaction mechanism of them with BChE was demonstrated by molecular docking and molecular dynamics simulation, showing that they could interact with catalytic active site and peripheral anionic site of BChE. These natural phenanthrenes provide new scaffold for the further design and optimization, with the aim to discover new selective BChE inhibitors for the treatment of AD.

Phenanthrenes from Dendrobium senile and their pancreatic lipase inhibitory activity

From the whole plant of Dendrobium senile, a new phenanthrene namely 2,5,7-trihydroxy-4-methoxyphenanthrene (1) was isolated, together with seven known compounds including moscatin (2), 2,5-dihydroxy-4,9-dimethoxyphenanthrene (3), moscatilin (4), aloifol I (5), 4,4',8,8'-tetramethoxy[1,1'-biphenanthrene]-2,2',7,7'-tetrol (6), 2,2',7,7'-tetrahydroxy-4,4'-dimethoxy-1,1'-biphenanthrene (7) and bleformin G (8). The structure of the new compound was elucidated by analysis of its spectroscopic data. Moscatin (2) and 2,5-dihydroxy-4,9-dimethoxyphenanthrene (3) showed appreciable pancreatic lipase inhibitory effects when compared with the positive control orlistat.

Antiproliferative and Proapoptotic Effects of Phenanthrene Derivatives Isolated from Bletilla striata on A549 Lung Cancer Cells

Lung cancer continues to be the world’s leading cause of cancer death and the treatment of non-small cell lung cancer (NSCLC) has attracted much attention. The tubers of Bletilla striata are regarded as “an excellent medicine for lung diseases” and as the first choice to treat several lung diseases. In this study, seventeen phenanthrene derivatives, including two new compounds (1 and 2), were isolated from the tubers of B. striata. Most compounds showed cytotoxicity against A549 cells. An EdU proliferation assay, a cell cycle assay, a wound healing assay, a transwell migration assay, a flow cytometry assay, and a western blot assay were performed to further investigate the effect of compound 1 on A549 cells. The results showed that compound 1 inhibited cell proliferation and migration and promoted cell apoptosis in A549 cells. The mechanisms might correlate with the regulation of the Akt, MEK/ERK, and Bcl-2/Bax signaling pathways. These results suggested that the phenanthrenes of B. striata might be important and effective substances in the treatment of NSCLC.

The medicinal uses of the genus Bletilla in traditional Chinese medicine: A phytochemical and pharmacological review

ETHNOPHARMACOLOGICAL RELEVANCE

Different orchids are important in traditional medicine, and species belonging to the genus Bletilla are important. Bletilla species have been used for thousands of years in Traditional Chinese Medicine (TCM) for the treatment of several health disorders, such as gastrointestinal disorders, peptic ulcer, lung disorders, and traumatic bleeding etc. AIM OF THIS REVIEW: This review aims to provide a systematic overview and objective analysis of Bletilla species and to find the probable relationship between their traditional use, chemical constituents, and pharmacological activities, while assessing their therapeutic potential in treatment of different human diseases.

MATERIALS AND METHODS

Relevant literatures on Bletilla species have been collected using the keywords "Bletilla", "phytochemistry", and "pharmacology" in scientific databases, such as "PubMed", "Scifinder", "The Plant List", "Elsevier", "China Knowledge Resource Integrated databases (CNKI)", "Google Scholar", "Baidu Scholar", and other literature sources, etc. RESULTS: This review indicates the isolation and identification of over 261 compounds from this genus, till December 2020. These chemical isolates belong to the stilbenes (bibenzyls and phenanthrenes), flavonoids, triterpenoids, steroids, simple phenolics, and glucosyloxybenzyl 2-isobutylmalates classes of compounds. These compounds have been reported to be characteristically distributed in Bletilla striata (Thunb.) Rchb. f. (BS), Bletilla ochracea Schltr. (BO), and Bletilla formosana (Hayata) Schltr. (BF). The crude extracts and pure compounds derived from the three Bletilla species have reportedly exhibited a wide spectrum of in vitro and in vivo pharmacological effects, such as hemostatic, anti-inflammatory, anti-tumor, and anti-microbial activities. As a Traditional Chinese Medicine (TCM), Bletilla species or preparations containing Bletilla species have been used for the treatment of epistaxis, gastrointestinal bleeding, cough and hemoptysis, gastric and duodenal ulcer, and traumatic injuries. Thus, Bletilla species have proven potential both in traditional uses and scientific studies.

CONCLUSIONS

Pharmacological studies have validated the use of Bletilla species in the traditional medicine, especially hemorrhagic diseases. Polysaccharides and stilbenes are the major bioactive chemical constituents of Bletilla genus according to the literatures. However, the mechanism of action of these molecules is yet to be studied. In addition, a detailed comparative analysis of the phytochemistry and biological activities of the three Bletilla species (BS, BO and BF) is highly recommended for understanding their ethnopharmacological uses and applications in clinics. Clinical toxicity tests on BS have been found to be negative, but it can't be used with Aconitum carmichaeli in traditional uses. Furthermore, not many reports are present in the literature regarding the conservation of Bletilla species.

Dihydrophenanthrenes from medicinal plants of Orchidaceae: A review

The plants of Orchidaceae are widely distributed in the world, 47 species of which have been used as folk medicines with a long history. The tubers and stems of them exhibit diverse efficacy, including clearing heat and resolving toxin, moistening lung and relieving cough and promoting blood circulation. Since dihydrophenanthrenes were responsible for the medical purposes, the characteristic skeletons, pharmacological effects and clinical applications of dihydrophenanthrenes were summarized in this review, so as to provide a theoretical basis for the comprehensive study, development and application of DPs from medicinal plants of Orchidaceae.

Bletinib ameliorates neutrophilic inflammation and lung injury by inhibiting Src family kinase phosphorylation and activity

BACKGROUND AND PURPOSE

Neutrophil overactivation is crucial in the pathogenesis of acute lung injury (ALI). Bletinib (3,3'-dihydroxy-2',6'-bis(p-hydroxybenzyl)-5-methoxybibenzyl), a natural bibenzyl, extracted from the Bletilla plant, exhibits anti-inflammatory, antibacterial, and antimitotic effects. In this study, we evaluated the therapeutic effects of bletinib in human neutrophilic inflammation and LPS-mediated ALI in mice.

EXPERIMENTAL APPROACH

In human neutrophils activated with the formyl peptide (fMLP), we assessed integrin expression, superoxide anion production, degranulation, neutrophil extracellular trap (NET) formation, and adhesion through flow cytometry, spectrophotometry, and immunofluorescence microscopy. Immunoblotting was used to measure phosphorylation of Src family kinases (SFKs) and downstream proteins. Finally, a LPS-induced ALI model in male BALB/c mice was used to investigate the potential therapeutic effects of bletinib treatment.

KEY RESULTS

In activated human neutrophils, bletinib reduced degranulation, respiratory burst, NET formation, adhesion, migration, and integrin expression; suppressed the enzymic activity of SFKs, including Src, Lyn, Fgr, and Hck; and inhibited the phosphorylation of SFKs as well as Vav and Bruton's tyrosine kinase (Btk). In mice with ALI, the pulmonary sections demonstrated considerable amelioration of prominent inflammatory changes, such as haemorrhage, pulmonary oedema, and neutrophil infiltration, after bletinib treatment.

CONCLUSION AND IMPLICATIONS

Bletinib regulates neutrophilic inflammation by inhibiting the SFK-Btk-Vav pathway. Bletinib ameliorates LPS-induced ALI in mice. Further biochemical optimisation of bletinib may be a promising strategy for the development of novel therapeutic agents for inflammatory diseases.

Dimeric 9,10-dihydrophenanthrene derivatives from Bletilla striata and their atropisomeric nature

Four pairs of undescribed racemic bi(9,10-dihydro) phenanthrene and phenanthrene/bibenzyl atropisomers, bletistriatins A-D (1-4), along with 22 known compounds were isolated from the rhizomes of Bletilla striata. These dimeric derivatives were constructed through direct C-C connection or an oxygen bridge. The structures of new compounds were fully established by extensive analysis of MS, and 1D and 2D NMR spectroscopic data. Owing to sterically hindered rotation around the biaryl axis, these dimeric 9,10-dihydrophenanthrene derivatives can exist as a pair of enantiomers, but were isolated as racemates. Their racemates were separated to yield enantiomerically pure compounds by HPLC on an optically active stationary phase, and were stereochemically characterized on-line by circular dichroism (CD) spectroscopy (LC-CD coupling). Some isolates were evaluated for cytotoxicity against human cancer cell lines HL-60 and A549. Compounds 13, 17, and 20 showed cytotoxicity against HL-60 and A-549 cell lines with IC₅₀ values ranging from 2.56 to 8.67 μM.

Erianthridin suppresses non-small-cell lung cancer cell metastasis through inhibition of Akt/mTOR/p70S6K signaling pathway

Cancer metastasis is a major cause of the high mortality rate in lung cancer patients. The cytoskeletal rearrangement and degradation of extracellular matrix are required to facilitate cell migration and invasion and the suppression of these behaviors is an intriguing approach to minimize cancer metastasis. Even though Erianthridin (ETD), a phenolic compound isolated from the Thai orchid Dendrobium formosum exhibits various biological activities, the molecular mechanism of ETD for anti-cancer activity is unclear. In this study, we found that noncytotoxic concentrations of ETD (≤ 50 μM) were able to significantly inhibit cell migration and invasion via disruption of actin stress fibers and lamellipodia formation. The expression of matrix metalloproteinase-2 (MMP-2) and MMP-9 was markedly downregulated in a dose-dependent manner after ETD treatment. Mechanistic studies revealed that protein kinase B (Akt) and its downstream effectors mammalian target of rapamycin (mTOR) and p70 S6 kinase (p70^S6K) were strongly attenuated. An in silico study further demonstrated that ETD binds to the protein kinase domain of Akt with both hydrogen bonding and van der Waals interactions. In addition, an in vivo tail vein injection metastasis study demonstrated a significant effect of ETD on the suppression of lung cancer cell metastasis. This study provides preclinical information regarding ETD, which exhibits promising antimetastatic activity against non-small-cell lung cancer through Akt/mTOR/p70^S6K-induced actin reorganization and MMPs expression.

Phenanthrene, 9,10-dihydrophenanthrene and bibenzyl enantiomers from Bletilla striata with their antineuroinflammatory and cytotoxic activities

Thirteen undescribed phenanthrene and bibenzyl derivatives, named blestanols A-M, including one pair of biphenanthrene enantiomers, two bis 9,10-dihydrophenanthrene ethers, five pairs of 9,10-dihydrophenanthrene/bibenzyl atropisomers, one racemic 9,10-dihydrophenanthrene/bibenzyl dimer, one 9,10-dihydrophenanthrenebibenzyl ether, two pairs of bibenzyl derivatives, and one stilbene, together with 12 known analogues were isolated from the tubers of Bletilla striata. The structures were elucidated via spectroscopic data analysis. 15 compounds were purified to yield enantiomers (a, b) via chiral-phase HPLC, and their configurations were determined by optical rotation values and the comparison of the experimental and calculated electronic circular dichroism (ECD) curves. Blestanols K-L possessed a cycloheptene moiety, which is rarely observed in bibenzyl derivatives. A putative biosynthetic pathway for the identified components is deduced. Among these compounds, 14 compounds showed inhibition of NO production, with IC₅₀ values ranging from 5.0 to 19.0 μM. Eight compounds displayed selective cytotoxic activities against HCT-116, HepG2, BGC-823, A549 or U251 cancer cell lines, with IC₅₀ values ranging from 1.4 to 8.3 μM. In addition, their structure-activity relationships are discussed briefly.

Six phenanthrenes from the roots of Cymbidium faberi Rolfe. and their biological activities

A new phenanthrene compound, 7-(4-hydroxybenzyl)-8-methoxy-9,10- dihydrophenanthrene-2,5-diol (HMD), along with five known compounds (Coelonin, DD, Shancidin, HDP and MDD) were isolated from the roots of Cymbidium faberi Rolfe. (CFR). Their structures were identified using various spectroscopic methods. These compounds were reported for the first time in the genus. All isolated compounds were tested by radical-scavenging ability against 1,1-diphenyl-2-picryl-hydrazyl (DPPH), cytotoxic activity against three human cancer cell lines and inflammatory activity. Among them, Shancidin exhibited the stronger DPPH-scavenging activity (IC₅₀=6.67 ± 0.84 μΜ) and cytotoxic activity against three tumour cell lines. Except for HDP, all compounds dose-dependently suppressed production of NO, TNF-α, IL-6 in LPS induced mouse primary peritoneal macrophage and showed anti-inflammatory activity. Moreover, 18 compounds were identified by UHPLC-LTQ-Orbitrap-MS combined with MS database, which provides a basis for further research.

Full Transcriptome Analysis of Callus Suspension Culture System of Bletilla striata

Background

Bletilla striata has been widely used in the pharmacology industry. To effectively produce the secondary metabolites through suspension cultured cells of B. striata, it is important to exploring the full-length transcriptome data and the genes related to cell growth and chemical producing of all culture stages. We applied a combination of Real-Time Sequencing of Single Molecule (SMRT) and second-generation sequencing (SGS) to generate the complete and full-length transcriptome of B. striata suspension cultured cells.

Methods

The B. striata transcriptome was formed in de novo way by using PacBio isoform sequencing (Iso-Seq) on a pooled RNA sample derived from 23 samples of 10 culture stages, to explore the potential for capturing full-length transcript isoforms. All unigenes were obtained after splicing, assembling, and clustering, and corrected by the SGS results. The obtained unigenes were compared with the databases, and the functions were annotated and classified.

Results and conclusions

A total of 100,276 high-quality full-length transcripts were obtained, with an average length of 2530 bp and an N50 of 3302 bp. About 52% of total sequences were annotated against the Gene Ontology, 53,316 unigenes were hit by KOG annotations and divided into 26 functional categories, 80,020 unigenes were mapped by KEGG annotations and clustered into 363 pathways. Furthermore, 15,133 long-chain non-coding RNAs (lncRNAs) were detected. And 68,996 coding sequences were identified based on SSR analysis, among which 31 pairs of primers selected at random were amplified and obtained stable bands. In conclusion, our results provide new full-length transcriptome data and genetic resources for identifying growth and metabolism-related genes, which provide a solid foundation for further research on its growth regulation mechanisms and genetic engineering breeding mechanisms of B. striata.

Unraveling the complexity of complex mixtures by combining high-resolution pharmacological, analytical and spectroscopic techniques: antidiabetic constituents in Chinese medicinal plants

Medicinal plants have been widely used as (poly)pharmacological remedies and constitute a rich source for antidiabetic drug discovery. In the present study, forty medicinal plant samples collected in China were tested for inhibitory activity against α-glucosidase, α-amylase, and protein-tyrosine phosphatase 1B (PTP1B). Crude ethyl acetate extracts of Dioscorea bulbifera L., Boehmeria nivea Gaudich, Tinospora sagittata Gagnep. and Persicaria bistorta (L.) Samp. showed dual inhibitory activity towards α-glucosidase and PTP1B, and were chosen for further investigation. Subsequent dual high-resolution α-glucosidase/PTP1B profiling or triple high-resolution α-glucosidase/α-amylase/PTP1B profiling combined with HPLC-HRMS and NMR spectroscopy led to the identification of 28 metabolites with one or more bioactivities. Among these, three new phenanthrenes were identified from D. bulbifera, including one new biphenanthrene (10) exhibiting promising dual inhibitory activity towards α-glucosidase and PTP1B with IC50 values of 2.08 ± 0.19 and 3.36 ± 0.25 μM, respectively. Two triterpenoids and one fatty acid from B. nivea and T. sagittata as well as some commercially available fatty acids showed strong PTP1B inhibitory activity with IC50 values in the range of 4.89 ± 0.38 to 53.77 ± 4.20 μM.

Isolation, Structural Elucidation, Optical Resolution, and Antineuroinflammatory Activity of Phenanthrene and 9,10-Dihydrophenanthrene Derivatives from Bletilla striata

A phytochemical investigation of the aqueous EtOH extract of Bletilla striata tubers afforded 34 phenanthrene and 9,10-dihydrophenanthrene derivatives, including four new compounds, 1-4. These compounds were identified using physicochemical analyses and various spectroscopic methods. Twelve of these compounds were resolved into their enantiomers, and the absolute configurations were determined by comparison of experimental and calculated ECD spectra. The antineuroinflammatory activities were evaluated by measuring the inhibition of nitric oxide production in lipopolysaccharide-stimulated BV-2 microglial cells. Compounds 7, 32, and 33 displayed inhibitory activities, with IC₅₀ values of 1.9, 5.0, and 1.0 μM, respectively, suggesting that they should be subjected to development as potential inhibitors of neuroinflammation.

Antibacterial bibenzyl derivatives from the tubers of Bletilla striata

Ten previously undescribed bibenzyl derivatives (bletistrins A-J), including 5 that have hydroxyl-substituted chiral centres on the aliphatic bibenzyl bridge, along with twelve known bibenzyl derivatives, were isolated from the rhizomes of Bletilla striata. The structures of bletistrins A-J were primarily elucidated on the basis of their 1D and 2D NMR spectroscopic data. The absolute configurations of bletistrins A, D, F, H and I were determined by electronic circular dichroism (ECD) spectroscopic analysis and optical rotation value. Most of the isolated compounds were evaluated for their antibacterial activities against 3 g-positive bacterial strains and 1 g-negative bacterial strain. Bletistrins F, G, and J, bulbocol, shanciguol and shancigusin B showed inhibitory activities, with MICs of (3-28 μg/mL) against S. aureus ATCC 6538.

Quality evaluation and traceability of Bletilla striata by fluorescence fingerprint coupled with multiway chemometrics analysis

BACKGROUND

Traditional methods of evaluating herbs were mainly based on chromatographic techniques. They usually included tedious sample preparation procedures, taking tens of minutes to hours, and consume solvents as well as standards for external calibration. In this paper, the feasibility of employing a fluorescence fingerprint coupled with multi-way chemometrics analysis for quality evaluation and traceability of Bletilla striata were investigated.

RESULTS

Relative concentrations of four markers presented in B. striata were determined by using a four-component self-weighted alternating trilinear decomposition (SWATLD) model. These markers could be applied to accurate classification and quality control of B. striata samples from different regions. Furthermore, multiway principal component analysis, multilinear partial least squares discriminant analysis (PLS-DA), unfolded PLS-DA, and SWATLD-PLS-DA models were applied to classify the B. striata samples according to their geographic origins. Consistent results were obtained showing that B. striata samples could be successfully grouped based on their geographical origins and quality.

CONCLUSION

Our results revealed that the method developed can be used for quality evaluation and traceability of B. striata. Compared with the chromatographic methods, the method employed in this study was more convenient, simpler, and more sensitive. © 2018 Society of Chemical Industry.

Asperuloside and Asperulosidic Acid Exert an Anti-Inflammatory Effect via Suppression of the NF-κB and MAPK Signaling Pathways in LPS-Induced RAW 264.7 Macrophages

Hedyotis diffusa is a folk herb that is used for treating inflammation-related diseases in Asia. Previous studies have found that iridoids in H. diffusa play an important role in its anti-inflammatory activity. This study aimed to investigate the anti-inflammatory effect and potential mechanism of five iridoids (asperuloside (ASP), asperulosidic acid (ASPA), desacetyl asperulosidic acid (DAA), scandoside methyl ester (SME), and E-6-O-p-coumaroyl scandoside methyl ester (CSME)) that are presented in H. diffusa using lipopolysaccharide (LPS)-induced RAW 264.7 cells. ASP and ASPA significantly decreased the production of nitric oxide (NO), prostaglandin E₂ (PGE₂), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in parallel with the inhibition of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), TNF-α, and IL-6 mRNA expression in LPS-induced RAW 264.7 cells. ASP treatment suppressed the phosphorylation of the inhibitors of nuclear factor-kappaB alpha (IκB-α), p38, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK). The inhibitory effect of ASPA was similar to that of ASP, except for p38 phosphorylation. In summary, the anti-inflammatory effects of ASP and ASPA are related to the inhibition of inflammatory cytokines and mediators via suppression of the NF-κB and mitogen-activated protein kinase (MAPK) signaling pathways, which provides scientific evidence for the potential application of H. diffusa.

Chemical constituents from Bletilla striata and their NO production suppression in RAW 264.7 macrophage cells

A novel glucoside bletilloside A (1) was isolated from the tubers of Bletilla striata, together with seven known compounds (2-8). Their structures were determined on the basis of extensive spectroscopic analyses. All compounds were evaluated for the inhibition on NO production effects in RAW 264.7 macrophage cells, while militarine (4) and dactylorhin A (5) exhibited moderate inhibitory effects.

Survey of natural products reported by Asian research groups in 2016

The new natural products reported in peer-reviewed articles in 2016 in journals with good reputations were reviewed and analyzed. The advances that Asian research groups made in the field of natural products chemistry in 2016 were summarized. Compounds with unique structural features and/or promising bioactivities originating from Asian natural sources were discussed based on structural classification.

Chemical Constituents from the Aerial Parts of Cyrtopodium paniculatum

We report the first phytochemical study of the neotropical orchid Cyrtopodium paniculatum. Eight new compounds, including one phenanthrene 1, one 9,10-dihydro-phenanthrene 2, one hydroxybenzylphenanthrene 3, two biphenanthrenes 4–5, and three 9,10 dihydrophenanthrofurans 6–8, together with 28 known phenolic compounds, mostly stilbenoids, were isolated from the CH₂Cl₂ extract of its leaves and pseudobulbs. The structures of the new compounds were established on the basis of extensive spectroscopic methods.