Termipaniculatones A-F, chalcone-flavonone heterodimers from Terminthia paniculata, and their protective effects on hyperuricemia and acute gouty arthritis.

Terminthia paniculata (Sanyeqi) is widely used for treating inflammation and rheumatic arthritis in the folk areas of Yunnan province, China. Its total extract was first revealed with xanthine oxidase (XO) inhibitory activity in vitro and anti-hyperuricemic effect in vivo. Bioassay-guided separation on Fr. A5 yielded six chalcone-flavonone heterodimers, termipaniculatones A-F. Their structures were elucidated based on extensive spectroscopic analyses involving HRESIMS, 1D and 2D NMR, UV, IR and [α]D, and the absolute configuration of termipaniculatone F was verified by ECD calculation. Termipaniculatones A and E showed obvious XO inhibitory activity with IC50 values of 55.6 and 89.5 µM, respectively, which took effects via a mix-type mode. A molecular modeling study revealed that termipaniculatone A was well located into the active site of XO by interacting with Glu802, Arg880, Thr1010 and Val1011 residues. Termipaniculatone A showed anti-hyperuricemic effects by decreasing serum uric acid levels and inhibiting XO activity in both serum and liver on potassium oxonate (PO)-induced hyperuricemia mice, and anti-inflammatory activity through alleviating paw swelling on monosodium urate (MSU)-induced mice, at the concentration of 20 mg/kg. This is the first time to reveal the anti-hyperuricemic and anti-acute gouty arthritis potency of T. paniculata and the characteristic biflavonoids as active constituents, which provides valuable information for searching new XO inhibitors from natural sources.

Chepraecoxins A-G, ent-Kaurane Diterpenoids with α-Glucosidase Inhibitory Activities from Chelonopsis praecox.

Our random bioassay revealed that the CHCl3 part of Chelonopsis praecox (Lamiaceae) showed significant activity against α-glucosidase with the inhibitory rate of 99.6 ± 0.4 % (330 µg/mL). Bioassay-guided isolation yielded seven new ent-kaurane diterpenoids, chepraecoxins A-G (1-7), and three known ones (8-10), driven by LC-MS analyses. The structures of chepraecoxins A-G (1-7) were elucidated by X-ray crystallographic and extensive spectroscopic analyses. Compounds 1, 6, and 10 showed obvious α-glucosidase inhibitory effects with IC50 values of 305.0, 361.0 and 174.5 µM, respectively. Enzyme kinetics study suggested that compound 1 inhibited the α-glucosidase by a noncompetitive type mechanism (Ki = 354.4 µM).

Phytochemical and Health-Beneficial Progress of Turnip (Brassica rapa).

Despite the advancement of medical science, diseases are part-and-parcel of human life. Plants have provided humans with medicines since time immemorial, and are still one of the primary sources for drug discovery. Brassica rapa L., commonly known as turnip, is one of the world's oldest cultivated vegetables. Besides being an important vegetable and source of oil, turnip is also used as a traditional medicine for the treatment of headaches, chest complaints, rheumatisms, oedemas, gonorrhoea, syphilis, and rabies. Glucosinolates and isothiocyanates (mainly 2-phenylethyl, 4-pentenyl, and 3-butenyl derivatives) are the main constituents of turnip with diverse bioactivities, especially for the protective effect against cancers. Besides, flavonoids, phenolics, indoles and volatiles are also concomitant in this plant. Pharmacological investigation on turnip revealed the antitumor, antihypertensive, antidiabetic, antioxidant, antiinflammatory, hepatoprotective, and nephroprotective effects. The anticancer property was found to be the most promising biological activity of turnip with 2-phenylethyl isothiocyanate, phenylpropionitrile, brassicaphenanthrene A, 6-paradol, and trans-6-shogaol as the major active constituents. Flavonoids and phenolics with high free radical scavenging activity should be corresponding to the antioxidant effects. Arvelexin, an indole derivative in turnip, was reported with various effects involving antiinflamatory, antihypertensive and hypolipidemic potency. In spite of many studies concerning either the chemical constituents or the biological activities of turnip, only a few cases disclosed the active ingredients responsible for diverse bioactivities. This review summarizes the research progress on the chemistry and health-benefits of turnip over the past 20 years to provide a reference for the further investigation.

Antidepressant potential of Uncaria rhynchophylla and its active flavanol, catechin, targeting melatonin receptors.

ETHNOPHARMACOLOGICAL RELEVANCE: Traditional Chinese medicines (TCMs) are fascinating sources for natural drug candidates. Uncaria rhynchophylla (Gouteng) is a famous TCM used for alleviating central nervous system (CNS) disorders, while its antidepressant constituents are still disputed. AIM OF THE STUDY: The present study was designed to assess the antidepressant property of U. rhynchophylla and characterize the active constituents targeting melatonin receptors which are closely related to CNS diseases. MATERIALS AND METHODS: The total extract and each fraction of U. rhynchophylla were extensively assessed for their agonistic activity on melatonin receptors in vitro. The following bioassay-guided fractionation yielded the active constituents, whose activity was confirmed by dose-dependent bioassay and antagonistic experiment on HEK293 cells. Their antidepressant effects were evaluated on forced swimming test (FST), tail suspension test (TST) and open-field test (OFT) mice models in vivo. Their metabolic profiles in mice plasma were analyzed by LCMS-IT-TOF. RESULTS: The stems and hooks of U. rhynchophylla were revealed with agonistic activity on melatonin receptors (MT1 and MT2). Under the guidance of bioassay, two flavanols, catechin and epicatechin were obtained and showed obviously activity agitating MT1 (EC50 = 25.8 and 156.1 µM) and MT2 (EC50 = 47.3 and 208.8 µM) receptors. The agonistic activity of catechin on melatonin receptors can be antagonized by luzindole at the concentrations of 1.57-100 µM. Catechin could significantly reduce the immobility time in both FST and TST mice models at doses of 80 and 40 mg/kg, without obvious effect on locomotor activity in OFT mice model. Five phase II (M1-M5) and one phase I (M6) metabolites of catechin were detected in mice plasma after intragastric (i.g.) administration. CONCLUSION: Catechin is a potent antidepressant candidate from U. rhynchophylla by targeting melatonin receptors. The main metabolic pathways of catechin in mice plasma are glucuronidation (M3) and methylated glucuronidation (M4 and M5). This study provides valuable information for understanding the antidepressant potency of Gouteng and its active constituents.

LC-MS guided isolation of gracilistones A and B, a pair of diastereomeric sesquiterpenoids with an unusual tetrahydrofuran-fused tricyclic skeleton from Acanthopanax gracilistylus and their potential anti-inflammatory activities.

Gracilistones A (1) and B (2), two new eudesmane-type sesquiterpenoids with an unusual tetrahydrofuran-fused 6/6/5 tricyclic ring system, were obtained from Acanthopanax gracilistylus under the guidance of LC-MS investigation. Their structures and absolute configurations were assigned by extensive spectroscopic analyses and quantum calculation methods. Compounds 1 and 2 showed potent inhibitory activity against LPS-induced nitric oxide production in RAW 264.7 macrophages, compared with the positive control L-NMMA. In addition, compounds 1 and 2 were also evaluated for their antioxidant (DPPH• and ABTS•+) and xanthine oxidase (XO) inhibitory activities, and they exhibited weak inhibitory effects at 100 µM.

Anti-hepatitis B virus effects of the traditional Chinese herb Artemisia capillaris and its active enynes.

ETHNOPHARMACOLOGICAL RELEVANCE: Artemisia capillaris (Yin-Chen) is a famous traditional Chinese medicine (TCM) for treating acute and chronic hepatitis in China. Enynes are one type of characteristic constituents in this herb, while their anti-hepatitis B virus (anti-HBV) properties have not been systemically investigated. AIM OF THE STUDY: This study is to reveal the active part of A. capillaris, and systemically investigate the enynes and their anti-HBV activity. MATERIALS AND METHODS: The total extract and each fraction of A. capillaris were assayed for the anti-HBV activity to reveal the active part. Bioassay-guided fractionation using various chromatographic techniques yielded the enynes, whose structures were elucidated by spectroscopic analyses and ECD calculations. The anti-HBV properties inhibiting HBsAg and HBeAg secretions and HBV DNA replication were evaluated on HepG 2.2.15 cell line in vitro. RESULTS: ACT-2 and ACT-3 was revealed to be the respective active and toxic part of A. capillaris. Twelve enynes (1-12) involving four new ones (1-4) and two unusual enyne analogs (13-14) were isolated from the active part (ACT-2). All the isolates were assayed for their anti-HBV activity, and the preliminary structure-activity relationships were summarized based on the structural features. In particular, compound 4 could significantly inhibit the secretions of HBsAg and HBeAg, and HBV DNA replication with IC50 values of 197.2 (SI > 5.1), 48.7 (SI > 20.5) and 9.8 (SI > 102) µM. CONCLUSIONS: Enynes are responsible for the anti-HBV effects of A. capillaris. Hydroxyl and glycosyl groups are preferable for maintaining activity. This is the first time to systematically investigate the anti-HBV activity of enynes in A. capillaris, which provides valuable information for understanding the ethnopharmacological application of Yin-Chen.

LC-MS guided isolation of diterpenoids from Sapium insigne with α-glucosidase inhibitory activities.

Ten new (1-10) and ten known (11-20) diterpenoids involving ent-atisane, ent-seco-atisane, ent-kaurane and ent-seco-kaurane types were isolated from Sapium insigne under the guidance of LCMS-IT-TOF analyses. Their structures were characterized by extensive spectroscopic analyses (HRESIMS, UV, IR, 1D and 2D NMR). A putative biosynthetic pathway was proposed for ent-seco-atisane diterpenoids. Their inhibitory activities on α-glucosidase in vitro were tested for the first time. Compound 4 showed moderate inhibitory effect on α-glucosidase with an IC50 value of 0.34 mM via a noncompetitive inhibition mechanism (Ki = 0.27 mM). The preliminary structure-activity relationships of the ent-atisane diterpenoids inhibiting α-glucosidase were discussed.

Pheophytin analogues from the medicinal lichen Usnea diffracta.

A new pheophytin, (132S, 17S, 18S)-132-hydroxy-20-chloro-ethylpheophorbide a (3), along with two known analogues (1-2) were isolated from the lichen Usnea diffracta Vainio (Parmeliaceae). Among them, compound 3 was a rare C-20-chloro type pheophytin obtained from lichens. Their structures were elucidated by extensive spectroscopic analysis, and all the compounds were obtained for the first time from U. diffracta. Compounds (1-3) were evaluated for their xanthine oxidase (XO) inhibitory activities in vitro, and the results showed that 1-3 possessed significant enzyme inhibitory actions with IC50 values of 46.9 ± 3.8, 75.9 ± 7.4 and 42.1 ± 1.7 µg/mL, respectively.

Bioassay-guided isolation of saikosaponins with agonistic activity on 5-hydroxytryptamine 2C receptor from Bupleurum chinense and their potential use for the treatment of obesity.

5-Hydroxytryptamine 2C (5-HT2C) receptor is one of the major targets of anti-obesity agents, due to its role in regulation of appetite. In the present study, the 70% EtOH extract of the roots of Bupleurum chinense was revealed to have agonistic activity on 5-HT2C receptor, and the subsequent bioassay-guided isolation led to identification of several saikosaponins as the active constituents with 5-HT2C receptor agonistic activity in vitro and anti-obesity activity in vivo. The new compound, 22-oxosaikosaponin d (1), was determined by extensive spectroscopic analyses (HR-ESI-MS, IR, and 1D and 2D NMR). The primary structure-activity relationship study suggested that the intramolecular ether bond between C-13 and C-28 and the number of sugars at C-3 position were closely related to the 5-HT2C receptor agonistic activity. Saikosaponin a (3), the main saponin in B. chinense, showed obviously agonistic activity on 5-HT2C receptor with an EC50 value of 21.08 ± 0.33 µmol·L-1in vitro and could reduce food intake by 39.1% and 69.2%, and weight gain by 13.6% and 16.4%, respectively, at 3.0 and 6.0 mg·kg-1in vivo. This investigation provided valuable information for the potential use of B. chinense as anti-obesity agent.

Compounds from Polyphaga plancyi and their inhibitory activities against JAK3 and DDR1 kinases.

Plancyamides A (1) and B (3), plancypyrazine A (2), and plancyols A (4) and B (5), five new compounds (1-5), and three known ones (6-8), were isolated from the whole bodies of Polyphaga plancyi Bolivar. Their structures were elucidated by a combination of spectroscopic analyses including 1D and 2D NMR, and HRESIMS. Among them, compound 3 is racemic, chiral HPLC separation afforded its respective enantiomers. The absolute configuration of 1 was assigned by computational methods. Biological evaluation of all the compounds with exception of 7 and 8 discloses that compounds 2 and 4 could inhibit JAK3 kinase with IC50 values of 12.6 and 5.0µM, respectively. In addition, compound 4 exhibit inhibitory activity towards DDR1 kinase with IC50 value of 4.87µM.

LC-MS guided isolation of ent-kaurane diterpenoids from Nouelia insignis.

The preliminary LC-MS investigation on the stems of Nouelia insignis manifested the existence of diterpenoids. As a result, 15 ent-kaurane diterpenoids, including 7 new glycosides (nouelosides A-G, 1-7), were isolated under the direction of LC-MS analysis. The new compounds were determined by extensive spectroscopic analysis including HRESIMS, 1D and 2D NMR data and chemical methods. Compounds 6 and 15 with the exo-methylene cyclopentanone functional group exhibited obvious nitric oxide production inhibitory activity with IC50 values of 3.84±0.20 and 3.19±0.25µM.

Bioactivity-guided isolation of anti-hepatitis B virus active sesquiterpenoids from the traditional Chinese medicine: Rhizomes of Cyperus rotundus.

ETHNOPHARMACOLOGICAL RELEVANCE: The rhizome of Cyperus rotundus (C. rotundus) is a well-known traditional Chinese medicine to cure hepatitis in many formulae, but the active components responsible for hepatitis have not been elucidated. According to our bioassay on HepG2.2.15 cell line in vitro, the ethanol extract of C. rotundus demonstrated potent anti-HBV activity. This current study was designed to isolate and identify the anti-HBV active constituents from the rhizomes of C. rotundus. MATERIAL AND METHODS: Bioactivity and LC-MS guided fractionation on the extract of C. rotundus using various chromatographic techniques including open-column, Sephadex LH-20 and semi-preparative high performance liquid chromatography led to the isolation and identification of thirty-seven sesquiterpenoids. Structural elucidation of the isolates was carried out by extensive spectroscopic analyses (UV, IR, HRMS, 1D- and 2D -NMR). The anti-HBV activity and cytotoxicity were evaluated on the HBV-transfected HepG2.2.15 cell line in vitro. The cytotoxicity effects of the isolates were assessed by a MTT assay. The secretions of HBsAg and HBeAg in the culture medium were detected by ELISA method, and the load of HBV DNA was quantified by real-time fluorescent PCR technique. RESULTS: Five new patchoulane-type sesquiterpenoids, namely cyperene-3, 8-dione (1), 14-hydroxy cyperotundone (2), 14-acetoxy cyperotundone (3), 3ß-hydroxycyperenoic acid (4) and sugetriol-3, 9-diacetate (5), along with 32 known sesquiterpenoids were isolated from the active fractions of C. rotundus. Compounds 2 and 3 were the first cyperotundone-type sesquiterpenoids with a hydroxyl group at C-14 position. Nine eudesmane-type sesquiterpenoids (15-21 and 23-24) significantly inhibited the HBV DNA replication with IC50 values of 42.7±5.9, 22.5±1.9, 13.2±1.2, 10.1±0.7, 14.1±1.1, 15.3±2.7, 13.8±0.9, 19.7±2.1 and 11.9±0.6 µM, respectively, of which, compounds 17, 21, 23 and 24 possessed high SI values of 250.4, 125.5,>259.6 and 127.5, respectively. Two patchoulane-type sesquiterpenoids (4 and 7) effectively suppressed the secretion of HBsAg in a dose-dependent manner with IC50 values of 46.6±14.3 (SI=31.0) and 77.2±13.0 (SI=1.7) µM, respectively. Compounds 2, 8, 12, 15, 17 and 25 possessed moderate activities against HBeAg secretion with IC50 values of 162.5±18.9 (SI=13.3), 399.2±90.0 (SI=10.6), 274.7±70.8 (SI=5.2), 313.9±87.5 (SI=7.2), 334.0±70.4 (SI=9.9) and 285.3±20.9 (SI=15.5) µM, respectively. CONCLUSIONS: This is the first study to reveal the anti-HBV constituents of C. rotundus, demonstrating that the eudesmane-type sesquiterpenoids might contribute to the anti-HBV activity of the rhizomes of C. rotundus.