Annotation and Identification of Phytochemicals from Eleusine indica Using High-Performance Liquid Chromatography Tandem Mass Spectrometry: Databases-Driven Approach.

Eleusine indica (L.) Gaertn is a perennial herb belonging to the Poaceae family. As the only species of Eleusine found abundantly in Malaysia, it is locally known as "rumput sambau" and has been traditionally used to treat various ailments including pain relief from vaginal bleeding, hastening the placenta delivery after childbirth, asthma, hemorrhoids, urinary infection, fever, and as a tonic for flu-related symptoms. A diverse array of biological activities have been reported for the plant, such as antimicrobial, cytotoxic, anticonvulsant, anti-inflammatory, analgesic, antipyretic, and hepatoprotective action. Despite many reports on its traditional uses and biological activities, limited chemical databases are available for the plant. Thus, the aims of this study were to annotate and identify the phytochemical constituents in the methanolic extract of E. indica through tandem LCMS-based analysis techniques using MZmine, GNPS, Compound Discoverer, and SIRIUS platforms. This technique managed to identify a total of 65 phytochemicals in the extract, comprising primary and secondary metabolites, and was verified by the isolation of one of the identified phytochemicals. The structural elucidation mainly using 1D and 2D NMR as well as comparison with values in the literature confirms the isolated phytochemical to be a 3-OH anomer of loliolide, a benzofuran-type of compound, which consequently increases the level of confidence in the applied technique. The research describes a useful method for the fast and simultaneous identification of phytochemicals in E. indica, contributing to the study of the chemical properties of the genus and family.

Effect of Storage Temperatures on Physico-Chemicals, Phytochemicals and Antioxidant Properties of Watermelon Juice (Citrullus lanatus).

Watermelon (Citrullus lanatus) consists of high moisture content and is favoured for its juice products. The popular fruit has a tempting taste, sweet aroma and attractive flesh colour. It is enriched with phytochemicals and antioxidant properties that are beneficial to human health. Due to convenience, the majority of individuals are likely to consume watermelon juice. However, little is known about the fruit juice storage and temperatures that may affect its beneficial properties. This study investigated the effect of storage temperature at room temperature, refrigerator cold, refrigerator freeze and freeze-dried, and analyzed the juice physico-chemicals (weight loss, pH, ash, moisture, total soluble solid, browning and turbidity), phytochemicals (total phenolic, total flavonoid, lycopene and ß-carotene) and antioxidant scavenging activities during 9 days of storage. The results showed that watermelon juice was affected by storage temperatures and conditions with significant changes in physico-chemical appearance and decrease in total phytochemical content, thus consequently affecting their antioxidant activities during 9 days of storage. Although fresh watermelon juice can be consumed for its high nutritional values, freeze-drying is the preferable technique to retain its benefits and to delay juice degradation.

Absolute Configuration of Alkaloids from Uncaria longiflora through Experimental and Computational Approaches.

The structure elucidation of three new alkaloids named isoformosaninol (1), formosaninol (2), and longiflorine (3), isolated from the leaves of Uncaria longiflora var. pteropoda (Miq.) Ridsdale, along with their biosynthetic pathways are discussed. Their absolute structures were determined through a combination of physical data interpretation and quantum chemical calculations using the time-dependent density functional theory (TDDFT) method.

Chemical Constituents of Malaysian U. cordata var. ferruginea and Their in Vitro α-Glucosidase Inhibitory Activities.

Continuing our interest in the Uncaria genus, the phytochemistry and the in-vitro α-glucosidase inhibitory activities of Malaysian Uncaria cordata var. ferruginea were investigated. The phytochemical study of this plant, which employed various chromatographic techniques including recycling preparative HPLC, led to the isolation of ten compounds with diverse structures comprising three phenolic acids, two coumarins, three flavonoids, a terpene and an iridoid glycoside. These constituents were identified as 2-hydroxybenzoic acid or salicylic acid (1), 2,4-dihydroxybenzoic acid (2), 3,4-dihydroxybenzoic acid (3), scopoletin or 7-hydroxy-6-methoxy-coumarin (4), 3,4-dihydroxy-7-methoxycoumarin (5), quercetin (6), kaempferol (7), taxifolin (8), loganin (9) and ß-sitosterol (10). Structure elucidation of the compounds was accomplished with the aid of 1D and 2D Nuclear Magnetic Resonance (NMR) spectral data and Ultraviolet-Visible (UV-Vis), Fourier Transform Infrared (FTIR) spectroscopy and mass spectrometry (MS). In the α-glucosidase inhibitory assay, the crude methanolic extract of the stems of the plant and its acetone fraction exhibited strong α-glucosidase inhibition activity of 87.7% and 89.2%, respectively, while its DCM fraction exhibited only moderate inhibition (75.3%) at a concentration of 1 mg/mL. The IC50 values of both fractions were found to be significantly lower than the standard acarbose suggesting the presence of potential α-glucosidase inhibitors. Selected compounds isolated from the active fractions were then subjected to α-glucosidase assay in which 2,4-dihydroxybenzoic acid and quercetin showed strong inhibitory effects against the enzyme with IC50 values of 549 and 556 µg/mL compared to acarbose (IC50 580 µg/mL) while loganin and scopoletin only showed weak α-glucosidase inhibition of 44.9% and 34.5%, respectively. This is the first report of the isolation of 2-hydroxybenzoic acid, 2,4-dihydroxybenzoic acid and loganin from the genus and the first report of the α-glucosidase inhibitory potential of 2,4-dihydroxybenzoic acid.

Augmented Stat5 Signaling Bypasses Multiple Impediments to Lactogen-Mediated Proliferation in Human ß-Cells.

Pregnancy in rodents is associated with a two- to threefold increase in ß-cell mass, which is attributable to large increases in ß-cell proliferation, complimented by increases in ß-cell size, survival, and function and mediated mainly by the lactogenic hormones prolactin (PRL) and placental lactogens. In humans, however, ß-cell mass does not increase as dramatically during pregnancy, and PRL fails to activate proliferation in human islets in vitro. To determine why, we explored the human PRL-prolactin receptor (hPRLR)-Janus kinase 2 (JAK2)-signal transducer and activator of transcription 5 (STAT5)-cyclin-cdk signaling cascade in human ß-cells. Surprisingly, adult human ß-cells express little or no PRLR. As expected, restoration of the hPRLR in human ß-cells rescued JAK2-STAT5 signaling in response to PRL. However, rescuing hPRLR-STAT5 signaling nevertheless failed to confer proliferative ability on adult human ß-cells in response to PRL. Surprisingly, mouse (but not human) Stat5a overexpression led to upregulation of cyclins D1-3 and cdk4, as well as their nuclear translocation, all of which are associated with ß-cell cycle entry. Collectively, the findings show that human ß-cells fail to proliferate in response to PRL for multiple reasons, one of which is a paucity of functional PRL receptors, and that murine Stat5 overexpression is able to bypass these impediments.

Structure and absolute configuration of 20ß-Hydroxyprednisolone, a biotransformed product of predinisolone by the marine endophytic fungus Penicilium lapidosum.

The anti-inflammatory drug predinisolone (1) was reduced to 20ß-hydroxyprednisolone (2) by the marine endophytic fungus Penicilium lapidosum isolated from an alga. The structural elucidation of 2 was achieved by 1D- and 2D-NMR, MS, IR data. Although, 2 is a known compound previously obtained through microbial transformation, the data provided failed to prove the C20 stereochemistry. To solve this issue, DFT and TD-DFT calculations have been carried out at the B3LYP/6-31+G (d,p) level of theory in gas and solvent phase. The absolute configuration of C20 was eventually assigned by combining experimental and calculated electronic circular dichroism spectra and 3JHH chemical coupling constants.

A new triterpenoid from Sapium baccatum (Euphorbiaceae).

A new triterpene, malaytaraxerate (1), and four known compounds, taraxerol (2), taraxerone (3), docosyl isoferulate (4) and docosanoic acid 2',3'-dihydroxypropyl ester (5), were isolated from the acetone extract of Sapium baccatum stem bark. The structures of the isolated compounds were determined using several spectroscopic methods, including UV-Vis, FT-IR, 1D and 2D NMR, and mass spectrometry. Major isolated compounds were assayed for cytotoxicity. The chemotaxonomic significance of this plant was also studied.

Human pancreatic ß-cell G1/S molecule cell cycle atlas.

Expansion of pancreatic ß-cells is a key goal of diabetes research, yet induction of adult human ß-cell replication has proven frustratingly difficult. In part, this reflects a lack of understanding of cell cycle control in the human ß-cell. Here, we provide a comprehensive immunocytochemical "atlas" of G1/S control molecules in the human ß-cell. This atlas reveals that the majority of these molecules, previously known to be present in islets, are actually present in the ß-cell. More importantly, and in contrast to anticipated results, the human ß-cell G1/S atlas reveals that almost all of the critical G1/S cell cycle control molecules are located in the cytoplasm of the quiescent human ß-cell. Indeed, the only nuclear G1/S molecules are the cell cycle inhibitors, pRb, p57, and variably, p21: none of the cyclins or cdks necessary to drive human ß-cell proliferation are present in the nuclear compartment. This observation may provide an explanation for the refractoriness of human ß-cells to proliferation. Thus, in addition to known obstacles to human ß-cell proliferation, restriction of G1/S molecules to the cytoplasm of the human ß-cell represents an unanticipated obstacle to therapeutic human ß-cell expansion.

Cytoplasmic-nuclear trafficking of G1/S cell cycle molecules and adult human ß-cell replication: a revised model of human ß-cell G1/S control.

Harnessing control of human ß-cell proliferation has proven frustratingly difficult. Most G1/S control molecules, generally presumed to be nuclear proteins in the human ß-cell, are in fact constrained to the cytoplasm. Here, we asked whether G1/S molecules might traffic into and out of the cytoplasmic compartment in association with activation of cell cycle progression. Cdk6 and cyclin D3 were used to drive human ß-cell proliferation and promptly translocated into the nucleus in association with proliferation. In contrast, the cell cycle inhibitors p15, p18, and p19 did not alter their location, remaining cytoplasmic. Conversely, p16, p21, and p27 increased their nuclear frequency. In contrast once again, p57 decreased its nuclear frequency. Whereas proliferating ß-cells contained nuclear cyclin D3 and cdk6, proliferation generally did not occur in ß-cells that contained nuclear cell cycle inhibitors, except p21. Dynamic cytoplasmic-nuclear trafficking of cdk6 was confirmed using green fluorescent protein-tagged cdk6 and live cell imaging. Thus, we provide novel working models describing the control of cell cycle progression in the human ß-cell. In addition to known obstacles to ß-cell proliferation, cytoplasmic-to-nuclear trafficking of G1/S molecules may represent an obstacle as well as a therapeutic opportunity for human ß-cell expansion.

Regulated and reversible induction of adult human ß-cell replication.

Induction of proliferation in adult human ß-cells is challenging. It can be accomplished by introduction of cell cycle molecules such as cyclin-dependent kinase 6 (cdk6) and cyclin D1, but their continuous overexpression raises oncogenic concerns. We attempted to mimic normal, transient, perinatal human ß-cell proliferation by delivering these molecules in a regulated and reversible manner. Adult cadaveric islets were transduced with doxycycline (Dox)-inducible adenoviruses expressing cdk6 or cyclin D1. End points were cdk6/cyclin D1 expression and human ß-cell proliferation, survival, and function. Increasing doses of Dox led to marked dose- and time-related increases in cdk6 and cyclin D1, accompanied by a 20-fold increase in ß-cell proliferation. Notably, Dox withdrawal resulted in a reversal of both cdk6 and cyclin D1 expression as well as ß-cell proliferation. Re-exposure to Dox reinduced both cdk/cyclin expression and proliferation. ß-Cell function and survival were not adversely affected. The adenoviral tetracycline (tet)-on system has not been used previously to drive human ß-cell proliferation. Human ß-cells can be induced to proliferate or arrest in a regulated, reversible manner, temporally and quantitatively mimicking the transient perinatal physiological proliferation that occurs in human ß-cells.

c-myc and skp2 coordinate p27 degradation, vascular smooth muscle proliferation, and neointima formation induced by the parathyroid hormone-related protein.

Parathyroid hormone-related protein (PTHrP) contains a classical bipartite nuclear localization signal. Nuclear PTHrP induces proliferation of arterial vascular smooth muscle cells (VSMC). In the arterial wall, PTHrP is markedly up-regulated in response to angioplasty and promotes arterial restenosis. PTHrP overexpression exacerbates arterial restenosis, and knockout of the PTHrP gene results in decreased VSMC proliferation in vivo. In arterial VSMC, expression of the cell cycle inhibitor, p27, rapidly decreases after angioplasty, and replacement of p27 markedly reduces neointima development. We have shown that PTHrP overexpression in VSMC leads to p27 down-regulation, mostly through increased proteosomal degradation. Here, we determined the molecular mechanisms through which PTHrP targets p27 for degradation. S-phase kinase-associated protein 2 (skp2) and c-myc, two critical regulators of p27 expression and stability, and neointima formation were up-regulated in PTHrP overexpression in VSMC. Normalization of skp2 or c-myc using small interfering RNA restores normal cell cycle and p27 expression in PTHrP overexpression in VSMC. These data indicate that skp2 and c-myc mediate p27 loss and proliferation induced by PTHrP. c-myc promoter activity was increased, and c-myc target genes involved in p27 stability were up-regulated in PTHrP overexpression in VSMC. In primary VSMC, PTHrP overexpression led to increased c-myc and decreased p27. Conversely, knockdown of PTHrP in primary VSMC from PTHrP(flox/flox) mice led to cell cycle arrest, p27 up-regulation, with c-myc and skp2 down-regulation. Collectively, these data describe for the first time the role of PTHrP in the regulation of skp2 and c-myc in VSMC. This novel PTHrP-c-myc-skp2 pathway is a potential target for therapeutic manipulation of the arterial response to injury.

cMyc is a principal upstream driver of beta-cell proliferation in rat insulinoma cell lines and is an effective mediator of human beta-cell replication.

Adult human ß-cells replicate slowly. Also, despite the abundance of rodent ß-cell lines, there are no human ß-cell lines for diabetes research or therapy. Prior studies in four commonly studied rodent ß-cell lines revealed that all four lines displayed an unusual, but strongly reproducible, cell cycle signature: an increase in seven G(1)/S molecules, i.e. cyclins A, D3, and E, and cdk1, -2, -4, and -6. Here, we explore the upstream mechanism(s) that drive these cell cycle changes. Using biochemical, pharmacological and molecular approaches, we surveyed potential upstream mitogenic signaling pathways in Ins 1 and RIN cells. We used both underexpression and overexpression to assess effects on rat and human ß-cell proliferation, survival and cell cycle control. Our results indicate that cMyc is: 1) uniquely up-regulated among other candidates; 2) principally responsible for the increase in the seven G(1)/S molecules; and, 3) largely responsible for proliferation in rat ß-cell lines. Importantly, cMyc expression in ß-cell lines, although some 5- to 7-fold higher than normal rat ß-cells, is far below the levels (75- to 150-fold) previously associated with ß-cell death and dedifferentiation. Notably, modest overexpression of cMyc is able to drive proliferation without cell death in normal rat and human ß-cells. We conclude that cMyc is an important driver of replication in the two most commonly employed rat ß-cell lines. These studies reverse the current paradigm in which cMyc overexpression is inevitably associated with ß-cell death and dedifferentiation. The cMyc pathway provides potential approaches, targets, and tools for driving and sustaining human ß-cell replication.

Rauniticine-allo-oxindole B and rauniticinic-allo acid B, new heteroyohimbine-type oxindole alkaloids from the stems of Malaysian Uncaria longiflora var. pteropoda.

Two new heteroyohimbine-type oxindole alkaloids, rauniticine-allo-oxindole B and rauniticinic-allo acid B, have been successfully isolated from the stems extract of Malaysian Uncaria longiflora var. pteropoda. The structures of the two new alkaloids were determined by spectroscopic analysis.

Rauniticine-allo-oxindole B methanol monosolvate.

The title penta-cyclic oxindole alkadoid, isolated from Uncaria longiflora, crystallizes as a methanol solvate, C(20)H(22)N(2)O(4)·CH(4)O. The five-membered ring comprising the indole fused ring is nearly planar [maximum atomic deviation = 0.031 (2) Å], whereas the five-membered ring having alphatic C atoms adopts an envelope shape (with the tertiary N atom representing the flap). The six-membered ring that shares an N atom with the envelope-shaped ring adopts a chair shape; the six-membered ring having an O atom is sofa-shaped. The carb-oxy-lic acid group acts as a hydrogen-bond donor to a methanol mol-ecule; this, in turn, acts as a hydrogen-bond donor to the double-bond carboxyl O atom of an adjacent mol-ecule, generating a chain. Adjacent chains are linked by N-H⋯O hydrogen bonds, forming a layer motif.

Induction of human beta-cell proliferation and engraftment using a single G1/S regulatory molecule, cdk6.

OBJECTIVE: Most knowledge on human beta-cell cycle control derives from immunoblots of whole human islets, mixtures of beta-cells and non-beta-cells. We explored the presence, subcellular localization, and function of five early G1/S phase molecules-cyclins D1-3 and cdk 4 and 6-in the adult human beta-cell. RESEARCH DESIGN AND METHODS: Immunocytochemistry for the five molecules and their relative abilities to drive human beta-cell replication were examined. Human beta-cell replication, cell death, and islet function in vivo were studied in the diabetic NOD-SCID mouse. RESULTS: Human beta-cells contain easily detectable cdks 4 and 6 and cyclin D3 but variable cyclin D1. Cyclin D2 was only marginally detectable. All five were principally cytoplasmic, not nuclear. Overexpression of the five, alone or in combination, led to variable increases in human beta-cell replication, with the cdk6/cyclin D3 combination being the most robust (15% versus 0.3% in control beta-cells). A single molecule, cdk6, proved to be capable of driving human beta-cell replication in vitro and enhancing human islet engraftment/proliferation in vivo, superior to normal islets and as effectively as the combination of cdk6 plus a D-cyclin. CONCLUSIONS: Human beta-cells contain abundant cdk4, cdk6, and cyclin D3, but variable amounts of cyclin D1. In contrast to rodent beta-cells, they contain little or no detectable cyclin D2. They are primarily cytoplasmic and likely ineffective in basal beta-cell replication. Unexpectedly, cyclin D3 and cdk6 overexpression drives human beta-cell replication most effectively. Most importantly, a single molecule, cdk6, supports robust human beta-cell proliferation and function in vivo.