Structure Characterization, Antioxidant and Immunomodulatory Activities of Polysaccharide from Pteridium aquilinum (L.) Kuhn.

Pteridium aquilinum (L.) Kuhn (Pteridaceae family) has been widely used as a food and medicine in China and Korea. Previous studies indicate that P. aquilinum contains a variety of bioactive chemical components such as flavonoids, phenols, terpenoids, saponins, polysaccharides, and so on. In the present study, a novel polysaccharide (named as PAP-3) with average molecular weight of 2.14 × 105 Da was obtained from P. aquilinum. The structure was studied through physicochemical and spectroscopic analysis. The results indicated that PAP-3 consists of arabinose, rhamnose, fucose, galactose, mannose, and xylose in a molar ratio of 1.58:1.00:3.26:4.57:4.81:3.33. The polysaccharide is mainly composed of (1→2)-linked xylose and (1→3,6)-linked mannose on the main chain, with (1→2)-linked xylose, (1→6)-linked mannose, and (1→6)- and (1→3,6)-linked galactose as side chains. Galactose, fucose, and xylose are located at the end of the side chains. The in vitro immunomodulatory and antioxidant activities were assayed. PAP-3 has strong free-radical scavenging activity on DPPH and ABTS radicals and significant immunomodulatory activity on RAW264.7 cells. These data provide useful information for further study on the polysaccharides of P. aquilinum and their applications in the food and medical industries.

A comprehensive review on traditional uses, chemical compositions, pharmacology properties and toxicology of Tetrastigma hemsleyanum.

ETHNOPHARMACOLOGICAL RELEVANCE: Tetrastigma hemsleyanum Diels et Gilg (T.hemsleyanum), a rare herbal plant distributed in subtropical areas of mainland China, has become a focus of scientific attention in recent years because of its high traditional value, including uses for treatment of children with fever, pneumonia, asthma, rheumatism, hepatitis, menstrual disorders, scrofula, and pharynx pain. AIM: This systematic review aims to provide an insightful understanding of traditional uses, chemical composition, pharmacological effect and clinical application of T. hemsleyanum, and lay a foundation for the further study and for the utilization of T. hemsleyanum resource. MATERIALS AND METHODS: A domestic and overseas literature search in known databases was conducted for published articles using the relevant keywords. RESULTS: One hundred and forty-two chemical constituents identified from T. hemsleyanum have been reported, including flavonoids, phenolic acids, polysaccharide, organic acids, fatty acids, terpenoids, steroids, amino acid and others. Among these components, flavonoids and polysaccharides were the representative active ingredients of T. hemsleyanum, which have been widely investigated. Modern pharmacological studies have shown that these components exhibited various pharmacological activities, such as anti-inflammatory, antioxidant, antivirus, antitumor, antipyretic, anti-hepatic injury, immunomodulatory, antibacterial etc. Moreover, different toxicological studies indicated that the clinical dosage of T. hemsleyanum was safe and reliable. CONCLUSIONS: Modern pharmacological studies have well supported and clarified some traditional uses, and T. hemsleyanum has a good prospect for the development of new drugs due to these outstanding properties. However, the present findings did not provide an in-depth evaluation of bioactivity of the extracts, the composition of its active extracts was not clear. Moreover, they were insufficient to satisfactorily explain some mechanisms of action. Data regarding many aspects of T. hemsleyanum, such as links between the traditional uses and bioactivities, pharmacokinetics, quality control standard and the clinical value of active compositions is still limited which need more attention.

[Research advances on chemical constituents from Calycanthaceae plants and their pharmacological activities].

Calycanthaceae family comprises of four genera including Chimonanthus, Sinocalycanthus, Calycanthus, and Idiospermum. The plants of Calycanthaceae are popular ornamental shrubs and used as foods and medicines, which are mainly distributed in China, North America, and Australia. The plants of Calycanthaceae are rich in volatile components, alkaloids, sesquiterpenes and coumarins. Dimeric piperidinoquinoline and dimeric pyrrolidinoindoline alkaloids, dimeric and/or trimeric coumarins are characteristic compositions in these plants. In order to provide timely reference for further investigation and development of Calycanthaceae plants, we made a systemic review on chemical constituents, i.e. alkaloids, terpenoids, flavonoids, coumarins, and steroids, from Calycanthaceae plants, focusing on their chemical structures and pharmacological activities.

Caragaphenol a induces reactive oxygen species related apoptosis in human gastric cancer cells.

Caragaphenol A (CAA) is a novel resveratrol trimer isolated from the roots of Caraganastenophylla. However, the biological activity of CAA is still unknown. In the present study, we investigated the anticancer effects of CAA on gastric cancer cells. CAA selectively inhibited cell growth of human gastric cancer cells. Moreover, CAA potently induced cell cycle arrest at G2/M phase and apoptosis with the increased intracellular reactive oxidative species (ROS) level. Inhibition of ROS could partially rescue CAA-induced cell apoptosis. Additionally, DNA is not the target of CAA. CAA in combination with DDP or 5FU synergistically inhibited the growth of human gastric cancer cells. Altogether, our study provides the evidence for the potential therapeutic application of CAA on human gastric cancer.

Lignans from the shed trunk barks of the critically endangered plant Abies beshanzuensis and their anti-neuroinflammatory activities.

During a further and comprehensive phytochemical investigation on the shed trunk barks of the critically endangered plant Abies beshanzuensis, one new (1) and ten known (2-11) lignans with diverse structures were isolated. On the basis of spectroscopic methods, the new structure was established to be (7S,8R,8'R)-4'-methoxyl-α-conidendrin (1). Among the isolated lignans, (-)-matairesinol (5) and (-)-arctigenin (6) showed significant anti-neuroinflammatory activities by inhibiting the overproduction of nitric oxide in lipopolysaccharide-stimulated murine BV-2 microglial cells, with IC50 values of 11.5 and 19.0 µM, respectively.

Wallichinine reverses ABCB1-mediated cancer multidrug resistance.

Overexpression of ABCB1 in cancer cells is one of the main reasons of cancer multidrug resistance (MDR). Wallichinine is a compound isolated from piper wallichii and works as an antagonist of platelet activiating factor receptor to inhibit the gathering of blood platelet. In this study, we investigate the effect of wallichinine on cancer MDR mediated by ABCB1 transporter. Wallichinine significantly potentiates the effects of two ABCB1 substrates vincristine and doxorubicin on inhibition of growth, arrest of cell cycle and induction of apoptosis in ABCB1 overexpressing cancer cells. Furthermore, wallichinine do not alter the sensitivity of non-ABCB1 substrate cisplatin. Mechanistically, wallichinine blocks the drug-efflux activity of ABCB1 to increase the intracellular accumulation of rhodamine 123 and doxorubicin and stimulates the ATPase of ABCB1 without alteration of the expression of ABCB1. The predicted binding mode shows the hydrophobic interactions of wallichinine within the large drug binding cavity of ABCB1. At all, our study of the interaction of wallichinine with ABCB1 presented herein provides valuable clues for the development of novel MDR reversal reagents from natural products.

Therapeutic Potential of Steroidal Alkaloids in Cancer and Other Diseases.

Steroidal alkaloids are a class of secondary metabolites isolated from plants, amphibians, and marine invertebrates. Evidence accumulated in the recent two decades demonstrates that steroidal alkaloids have a wide range of bioactivities including anticancer, antimicrobial, anti-inflammatory, antinociceptive, etc., suggesting their great potential for application. It is therefore necessary to comprehensively summarize the bioactivities, especially anticancer activities and mechanisms of steroidal alkaloids. Here we systematically highlight the anticancer profiles both in vitro and in vivo of steroidal alkaloids such as dendrogenin, solanidine, solasodine, tomatidine, cyclopamine, and their derivatives. Furthermore, other bioactivities of steroidal alkaloids are also discussed. The integrated molecular mechanisms in this review can increase our understanding on the utilization of steroidal alkaloids and contribute to the development of new drug candidates. Although the therapeutic potentials of steroidal alkaloids look promising in the preclinical and clinical studies, further pharmacokinetic and clinical studies are mandated to define their efficacy and safety in cancer and other diseases.

Synergistic anticancer effects of triptolide and celastrol, two main compounds from thunder god vine.

Triptolide and celastrol are two main active compounds isolated from Thunder God Vine with the potent anticancer activity. However, the anticancer effect of triptolide in combination with celastrol is still unknown. In the present study, we demonstrated that the combination of triptolide with celastrol synergistically induced cell growth inhibition, cell cycle arrest at G2/M phase and apoptosis with the increased intracellular ROS accumulation in cancer cells. Pretreatment with ROS scavenger N-acetyl-L-cysteine dramatically blocked the apoptosis induced by co-treatment with triptolide and celastrol. Treatment with celastrol alone led to the decreased expressions of HSP90 client proteins including survivin, AKT, EGFR, which was enhanced by the addition of triptolide. Additionally, the celastrol-induced expression of HSP70 and HSP27 was abrogated by triptolide. In the nude mice with xenograft tumors, the lower-dose combination of triptolide with celastrol significantly inhibited the growth of tumors without obvious toxicity. Overall, triptolide in combination with celastrol showed outstanding synergistic anticancer effect in vitro and in vivo, suggesting that this beneficial combination may offer a promising treatment option for cancer patients.

Studies on the alkaloids of the calycanthaceae and their syntheses.

Plants of the Calycanthaceae family, which possesses four genera and about 15 species, are mainly distributed in China, North America and Australia. Chemical studies on the Calycanthaceae have led to the discovery of about 14 alkaloids of different skeletons, including dimeric piperidinoquinoline, dimeric pyrrolidinoindoline and/or trimeric pyrrolidinoindolines, which exhibit significant anti-convulsant, anti-fungal, anti-viral analgesic, anti-tumor, and anti-melanogenesis activities. As some of complex tryptamine-derived alkaloids exhibit promising biological activities, the syntheses of these alkaloids have also been a topic of interest in synthetic chemistry during the last decades. This review will focus on the structures and total syntheses of these alkaloids.

Resveratrol oligomers for the prevention and treatment of cancers.

Resveratrol (3,4',5-trihydroxystilbene) is a naturally derived phytoalexin stilbene isolated from grapes and other plants, playing an important role in human health and is well known for its extensive bioactivities, such as antioxidation, anti-inflammatory, anticancer. In addition to resveratrol, scientists also pay attention to resveratrol oligomers, derivatives of resveratrol, which are characterized by the polymerization of two to eight, or even more resveratrol units, and are the largest group of oligomeric stilbenes. Resveratrol oligomers have multiple beneficial properties, of which some are superior in activity, stability, and selectivity compared with resveratrol. The complicated structures and diverse biological activities are of significant interest for drug research and development and may provide promising prospects as cancer preventive and therapeutical agents. This review presents an overview on preventive or anticancer properties of resveratrol oligomers.

Chemical constituents from Melastoma dodecandrum and their inhibitory activity on interleukin-8 production in HT-29 cells.

In search of anti-inflammatory lead compounds from traditional Chinese medicines, a bioassay-guided phytochemical study on Melastoma dodecandrum was carried out. As a result, 18 compounds have been isolated. Their chemical structures were determined on the basis of their physicochemical properties and spectral data. Among the isolates, three pentacyclic triterpenoids, ursolic acid (1), asiatic acid (3) and terminolic acid (6), together with one tannin casuarinin (17), were found to significantly decrease interleukin-8 (IL-8) production in human colon cancer cells. The results imply, at least in part, that the anti-inflammatory effect of M. dodecandrum could be due to inhibition of IL-8 production, demonstrated by these naturally occurring compounds described above.

Triterpenoids as reversal agents for anticancer drug resistance treatment.

Overexpression of ATP-binding cassette (ABC) transporters in cancer cells results in multidrug resistance (MDR), which is one of the major obstacles in the treatment of cancer patients. None of the strategies to overcome MDR has been successfully applied in the clinic until now. Plenty of evidence shows that some triterpenoids function as reversal agents of MDR for anticancer drug resistance treatment. Here, we review the latest findings of reversing cancer MDR with triterpenoids. Findings are summarized showing that triterpenoids are MDR modulators and potential chemosensitizers. Finally, we contemplate future prospects of modulating MDR in the clinic.

[Chemical constituents of chloroform fraction from leaves of Chimonanthus salicifolius].

To explore anti-tumor active components of Chimonanthus salicifolius, the phytochemistry of the chloroform fraction from leaves extract was investigated by repeated silica gel column chromatography. Twelve compounds were isolated and their structures were identified by physicochemical properties and spectroscopic data analysis as 9-epi-blumenol C(1), blumenol C(2), (+)-dehydrovomifoliol (3), (+)-vomifoliol (4), robinlin (5), (-)-loliolide (6), isofraxidin (7), scopoletin (8), 6,7-dimethoxycoumarin (9), 6, 7, 8-trimethoxycoumarin (10), beta-sitostenone (11), and beta-stigmasterol(12). Compounds 1-6 belonging to nor-sesquiterpenoids were isolated from the family Calycanthaceae for the first time. Compound 1 was a new natural product. Compounds 7, 11 and 12 were obtained from this plant for the first time.

[Anti-HIV chemical constituents of aerial parts of Caragana rosea].

This study was intended to look for anti-HIV chemical constituents of aerial parts of Caragana rosea Turcz. Column chromatographic technique was used for the isolation and purification of constituents of Caragana rosea under the guide of anti-HIV assay. The structures were established on the basis of physical and chemical properties and spectroscopic data. Five compounds were obtained from the EtOAc fraction of aerial parts of Caragana rosea and identified as myricetin (1), mearnsetin (2), p-hydroxy cinnamic acid (3), cararosinol A (4) and cararosinol B (5). At the same time, one possible transformation route between cararosinol B and kobophenol A, another resveratrol tetramer isolated from this plant previously, was proposed. Compounds 4, 5 are new resveratrol tetramers, compounds 1 -3 were isolated from this plant for the first time. All compounds showed no activities in an in vitro assay against HIV-1.