You-Kai Xu

Limonoids from the Leaves and Twigs of Walsura yunnanensis.

Nine new cedrelone limonoids, namely, walsuranolide B (1), 11β-hydroxy-23-O-methylwalsuranolide (2), yunnanolide A (3), yunnanol A (4), 11β-hydroxyisowalsuranolide (5), 11β-hydroxy-1,2-dihydroisowalsuranolide (6), 1α,11β-dihydroxy-1,2-dihydroisowalsuranolide (7), 11β-hydroxy-1α-methoxy-1,2-dihydroisowalsuranolide (8), and yunnanolide B (9), together with a new cycloartane triterpenoid, (24S*,25R*)-cycloartane-3β,24,25,26-tetrol (10), were isolated from the leaves and twigs of Walsura yunnanensis. Their structures were elucidated on the basis of spectroscopic analysis and by comparison with literature data. Compounds 3 and 5 exhibited potent cytotoxicity against five human tumor cell lines with IC50 values in the range 2.2-4.2 μM.

Koumine, Humantenine, and Yohimbane Alkaloids from Gelsemium elegans

Nine new alkaloids of the koumine (1-4), humantenine (5-7), and yohimbane (8, 9) types as well as 12 known analogues were isolated from the leaves and vine stems of Gelsemium elegans. Compound 1 is the first N-4-demethyl alkaloid of the koumine type, compound 7 is the first nor-humantenine alkaloid, and compounds 8 and 9 are the first N-1-oxide and the first seco-E-ring alkaloids, respectively, of the yohimbane type. Compounds 1 and 7 exhibited moderate cytotoxicity against five human tumor cell lines with IC50 values in the range 4.6-9.3 μM.

Chemical composition, antimicrobial and anti-inflammatory activities of the essential oil from Maqian (Zanthoxylum myriacanthum var. pubescens) in Xishuangbanna, SW China.

ETHNOPHARMACOLOGICAL RELEVANCE Maqian (Zanthoxylum myriacanthum var. pubescens Huang) is widely consumed as an indigenous remedy for digestive disorders, detoxification, detumescence and analgesia by the ethnic groups in Xishuangbanna, SW China. A related species, Huajiao (Zanthoxylum schinifolium Sieb. et Zucc.), has similar uses in traditional Chinese medicine. We aimed to scientifically validate the traditional uses by investigating and comparing the chemical composition, antimicrobial and anti-inflammatory activities of the essential oils of Maqian and Huajiao. MATERIALS AND METHODS Essential oils were collected from the fruits of Maqian and Huajiao by simultaneous distillation extraction and identified by gas chromatography-mass spectrometry (GC-MS) analysis. To assess antimicrobial activity, the minimum inhibitory and bactericidal concentrations (MIC and MBC) against 7 microbial strains, including 5 food-borne pathogens, were evaluated by serial dilution with a standardized microdilution broth methodology. For anti-inflammatory activity, the cell viability and nitric oxide (NO) production were determined on lipopolysaccharide (LPS)-stimulated RAW 264.7 cells by MTS assay and the Griess reagent system, respectively. RESULTS The essential oil from Maqian is rich in limonene (67.06%) and has strong antimicrobial activity against the tested pathogens and spoilage organisms, with MIC ranging from 64 to1024µg/ml and MBC ranging from 64 to 2048µg/ml. It also showed anti-inflammatory activity by significantly inhibiting nitric oxide (NO) production induced by LPS in RAW 264.7 cells at 0.04‰ without effects on cell viability. Furthermore, it showed relatively stronger antimicrobial and anti-inflammatory activities than the essential oil from Huajiao. CONCLUSIONS Our findings not only justify the use of Maqian as an indigenous remedy for digestive disorders, detoxification, detumescence and analgesia, but also suggest that it could be promoted as a preferred substitute for Huajiao.

Gelsemium alkaloids, immunosuppressive agents from Gelsemium elegans

Bioassay-guided isolation of the stems of Gelsemium elegans has led to the isolation of two new Gelsemium alkaloids, 21-(2-oxopropyl)-koumine (1) and 11-methoxygelselegine (2), and two known alkaloids, koumine (3) and gelselegine (4). The structures of 1-2 were determined by spectroscopic (for both) and single-crystal X-ray diffraction (for 1) analysis. All compounds isolated were evaluated for their potential as immunosuppressive agents and the data suggested that Gelsemium alkaloids of different structural types possibly have potential as immunosuppressive agents.

Anti-inflammatory sesquiterpenoids from the Traditional Chinese Medicine Salvia plebeia : Regulates pro-inflammatory mediators through inhibition of NF-κB and Erk1/2 signaling pathways in LPS-induced Raw264.7 cells

ETHNOPHARMACOLOGICAL RELEVANCE Salvia plebeia R. Brown, a traditional Chinese medicinal herb, has been used to treat inflammatory diseases such as cough, hepatitis, and diarrhea for a long history. AIM OF THE STUDY The aim of the present study was to isolate and identify potential anti-inflammatory agents from the herb of S. plebeia, which may have contributed to its folk pharmacological use in the treatment of inflammatory diseases. MATERIAL AND METHODS The aerial parts of S. plebeia were extracted with 95% ethanol and separated by silica gel, RP-C18, Sephadex LH-20, and HPLC. The structures of the isolated compounds were elucidated by extensive spectroscopic analysis (MS, NMR, and X-ray). Anti-inflammatory activities of all compounds were evaluated by the model of LPS-induced up-regulated of NO in Raw264.7 macrophages. The expression levels of cytokine (TNF-α) and proteins (iNOS and COX-2) were assessed by ELISA kit and Western blotting analysis, respectively. Furthermore, the influences of salviplenoid A (1) on NF-κB and MAPK signaling pathways were determined by Western blotting analysis and immunofluorescence assay. RESULTS Six new (1-6, salviplenoids A-F) and ten known (7-16) sesquiterpenoids were isolated from the herb of S. plebeia. The absolute configurations of compounds 1, 2, and 7 were determined by X-ray diffraction. The new eudesmane-type sesquiterpenoid, salviplenoid A (1), significantly decreased the release of NO and TNF-α and the expression of proteins iNOS and COX-2. In addition, the biochemical mechanistic study indicated that 1 regulated the NF-κB dependent transcriptional activity through inhibiting the nuclear translocation of p50/p65 dimer and decreasing the phosphorylation of IκB and Erk1/2. CONCLUSIONS Among all sesquiterpenoids isolated from S. plebeian, the new salviplenoid A (1) exhibited the most potent anti-inflammatory activity in LPS-induced Raw264.7 cells via inhibition of NF-κB and Erk1/2 signaling pathways.

Protective effect of the essential oil of Zanthoxylum myriacanthum var. pubescens against dextran sulfate sodium-induced intestinal inflammation in mice.

BACKGROUND Zanthoxylum myriacanthum var. pubescens is an ethnic medicine for digestive disease known as Maqian. A previous report showed that the Maqian fruits essential oil (MQEO) exhibited an NO inhibitory effect on RAW 264.7 cells, but the effect on inflammatory disease in vivo remains unknown. PURPOSE To investigate the anti-inflammatory effect of Z. myriacanthum var. pubescens as potential candidate for the treatment of intestinal inflammation. STUDY DESIGN Evaluation of anti-inflammatory effect of MQEO using dextran sulfate sodium (DSS)-induced intestinal inflammation in mice and exploration of the mechanisms with THP-1 cells. METHODS C57BL/6 mice were provided drinking water containing 3% DSS for 10 days followed by normal drinking water for 3 days. MQEO (35 and 70mg/kg) were given 5 days before experiments and continued for another 13 days. At the end of experiments, mice were euthanized and colonic tissue was collected to be analyzed by H&E staining, RT-PCR and immunohistochemistry for evaluating the damage of colons, the mRNA levels of IL-1β, IL-6, IL-12p35 and TNF-α, and the expressions of myeloperoxidase (MPO) and matrix metalloproteinase-9 (MMP-9). The LPS-stimulated THP-1 cell line was used for exploring the role of inflammatory markers using ELISA, western blot and flow cytometry methods. RESULTS Oral administration of MQEO (35 and 70mg/kg) markedly attenuated the symptoms of intestinal inflammation, including diarrhea, rectal bleeding, and loss of body weight. It also reduced the shortening of colon length and histopathological damage. The expressions of MPO and MMP-9 and the mRNA levels of pro-inflammatory cytokines (IL-1β, IL-6 and IL-12p35) in colonic tissue significantly decreased after MQEQ treatment. The activation of NF-κB p65 in colonic mucosa was also markedly suppressed. In addition, MQEO significantly suppressed LPS-stimulated production of TNF-α and IL-1β, effectively blocked phosphorylation of IKK and IκB, and dose-dependently reduced LPS-stimulated expression of TLR4 in THP-1 cells at concentrations ranging from 0.01‰ to 0.05‰ (v/v). CONCLUSION MQEO exhibited protective effect against DSS-induced intestinal inflammation and the anti-inflammatory activity may be associated with TLR4 mediated NF-κB signaling pathway, suggesting it might be used as an anti-inflammatory agent.

Cytotoxic limonoids from Trichilia americana leaves

Ten cedrelone limonoids were isolated from the leaves of Trichilia americana. These compounds include americanolides A-D (1-4), 1,2-dihydrodeacetylhirtin (5), 1α-hydroxy-1,2-dihydrodeacetylhirtin (6), 1α-hydroxy-1,2-dihydrohirtin (7), 1α-methoxy-1,2-dihydrodeacetylhirtin (8), 11β-hydroxy-12α-propanoyloxycedrelone (9), and 1α,11β-dihydroxy-1,2-dihydrocedrelone (10), as well as two previously reported compounds, deacetylhirtin (11) and hirtin (12). Their structures were characterized on the basis of spectroscopic studies, and the assignment of the absolute configuration of americanolide A (1) was supported by single-crystal X-ray diffraction studies. The cytotoxic activities of all isolated compounds were also evaluated against five human tumour cell lines (HL-60, SMMC-7721, A-549, MCF-7, and SW-480) using an MTS assay. Compounds 11 and 12 showed significant cytotoxicity with IC50 values ranging from 0.1 to 0.5 μM, and compounds 5, 6, 7, 8, 9, and 10 exhibited potent or selective cytotoxic activity with IC50 values ranging from 1.0 to 39.6 μM.

Limonoids from the Fruits of Khaya ivorensis

Two new limonoids, namely 14,15-didehydroruageanin A (1) and 3-O-methyl- butyrylseneganolide A (2), were isolated from the fruits of Khaya ivorensis along with six known limonoids: seneganolide A (3), 1,3-dideacetylkhivorin (4), 7-deacetylkhivorin (5), 3-deacetylkhivorin (6), 1-deacetylkhivorin (7), and 3-deacetyl-7-oxokhivorin (8). All the compounds were evaluated for their cytotoxicity against five tumor cell lines.

An ethnobotanical study of the less known wild edible figs (genus Ficus) native to Xishuangbanna, Southwest China

BackgroundThe genus Ficus, collectively known as figs, is a key component of tropical forests and is well known for its ethnobotanical importance. In recent decades an increasing number of studies have shown the indigenous knowledge about wild edible Ficus species and their culinary or medicinal value. However, rather little is known about the role of these species in rural livelihoods, because of both species and cultural diversity.MethodsIn this study we 1) collected the species and ethnic names of wild edible Ficus exploited by four cultural groups in Xishuangbanna, Southwest China, and 2) recorded the collection activities and modes of consumption through semi-structured interviews, 3) investigated the resource management by a statistical survey of their field distribution and cultivation, and 4) compared and estimated the usage intensities by the grading method.ResultsThe young leaves, leaf buds and young or ripe syconia of 13 Ficus species or varieties are traditionally consumed. All the species had fixed and usually food-related ethnic names. All four cultural groups are experienced in the collection and use of edible Ficus species as vegetables, fruits or beverages, with the surplus sold for cash income. Different cultural groups use the Ficus species at different intensities because of differences in availability, forest dependency and cultural factors. Both the mountain and basin villagers make an effort to realize sustainable collection and meet their own and market needs by resource management in situ or cultivation.ConclusionsIn comparison with reports from other parts of the world, ethnic groups in Xishuangbanna exploited more edible Ficus species for young leaves or leaf buds. Most of the edible species undergo a gradient of management intensities following a gradient of manipulation from simple field gathering to ex situ cultivation. This study contributes to our understanding of the origins and diffusion of the knowledge of perception, application and managing a group of particular plant species, and how the local culture, economic and geographical factors influence the process.

Uncarilic Acid and Secouncarilic Acid, Two New Triterpenoids from Uucaria sessilifructus

Two new compounds, the 6-oxo oleanane-type triterpenoid uncarilic acid, and its 5,6-secotriterpenoid derivative, secouncarilic acid, were isolated from the hooks and stems of Uucaria sessilifructus together with seven known ursane-type triterpenoids. Uncarilic acid is the second 6-oxo oleanane-type triterpenoid ever reported, while secouncarilic acid is the first oleanane-type 5,6-secotriterpenoid. A plausible biosynthetic pathway from uncarilic acid to secouncarilic acid was also postulated. The inhibitory activities of all the nine compounds against LPS-induced nitric oxide production in RAW264.7 macrophages were evaluated.