Structure-antiemetic-activity of some diarylheptanoids and their analogues

Efficient total synthesis of three alpinoids via the Au(I)-catalyzed Meyer-Schuster rearrangement

The total syntheses of three structurally related natural products, deoxyalpinoid B, deoxyalpinoid A, and alpinoid F, are reported, and each features a Au(I)-catalyzed Meyer-Schuster rearrangement as the key step. The synthesis of alpinoid F is reported for the first time. The syntheses of these natural products, all of which exhibit potent anticancer activity, are readily amenable to the preparation of structural analogs.

An overview of the chemical composition and biological activities of essential oils from Alpinia genus (Zingiberaceae)

Alpinia Roxb. is the largest genus of the Zingiberaceae family. A large number of Alpinia species has been used as food and traditional medicines. Alpinia essential oils have been studied for their chemical profiles, in which 1,8-cineole, β-pinene, α-pinene, β-myrcene, camphor, γ-terpinene, p-cymene, geraniol, α-fenchyl acetate, ocimene, methyl cinnamate, and β-caryophyllene have been found to be the major compounds. Essential oils isolated from Alpinia plants have been reported to have antimicrobial, cytotoxic, antioxidant, anti-inflammatory, anti-asthmatic, tyrosinase inhibitory, insecticidal, and larvicidal activities and slimming aromatherapy. In this review, the comprehensive information regarding the volatile components of various Alpinia plants, the bioactivities of Alpinia essential oils and their major compounds are provided.

Natural Products & Bioactivity Inspired Synthetic Pursuits Interfacing with Carbohydrates: Ongoing Journey with C-Glycosides

Natural products, remains the most important source for the discovery of new drugs for the treatment of human diseases. This has inspired the synthetic community to design and develop mimics of natural products either to answer important questions in biology or to explore their therapeutic potentials. Glycosides present themselves abundantly in nature, right from the cell surface receptors to natural products of any origin. The O-Glycosides are hydrolytically less stable compared to C-glycosides and this feature has presented a great opportunity for drug discovery. The discovery of Dapagliflozin, an SGLT inhibitor and C-glucoside, for the treatment of diabetes is one such example. Aryl acyl-anion chemistry has been explored for the synthesis of 2-deoxy-C-aryl furanoside/pyranoside/septanosides. Besides success, the studies have provided valuable insight into the natural propensities of the architectural framework for the cascade to furan derivatives. The aryl acyl-anion chemistry has also enabled the synthesis of biologically active diaryl heptanoids. Inspired from sucesss of Dapagliflozin, new analogues have been synthesized with pyridine and isocoumarin heterocycle as the proximal ring. C-glucosides of isoliquiritigenin have been synthesized for the first time and evaluated as an efficient aldose reductase inhibitor. The synthesis and evaluation of acyl-C-β-D-glucosides and benzyl-C-β-D-glucoside as glucose-uptake promoters has revealed promise in small molecules. The concept of building blocks has been used to obtain natural oxylipins, D-xylo and L-xylo-configured alkane tetrols and novel lipophilic ketones with erythro/threo configured trihydroxy polar head-group as possible anti-mycobacterial agents.

Anti-inflammatory activity of naturally occuring diarylheptanoids - A review

Inflammation involving the innate and adaptive immune systems is a normal response to infection. However, if it becomes uncontrolled, inflammation may result in autoimmune or auto inflammatory disorders, neurodegenerative diseases or cancers. The currently available anti-inflammatory drug therapy is often not successful or induces severe side effects. Thus, the search of new therapeutic options for the treatment of inflammation is highly required. Medicinal plants have been an interesting source for obtaining new active compounds. Diarylheptanoids characterized by a 1, 7-diphenylheptane structural skeleton, are a class of secondary plant metabolites that have gained increasing interest over the last few decades due to a wide variety of biological activities. This review covers 182 natural linear or macrocyclic diarylheptanoids described in the period of 1982 to 2020 with anti-inflammatory activities evaluated using quantified in vitro and/or in vivo assays. All of these data highlight the pharmacological potential of these natural compounds to act as anti-inflammatory drugs.

Syntheses and antibacterial activities of 4 linear nonphenolic diarylheptanoids

Four linear nonphenolic diarylheptanoids were synthesized and their antibacterial activities were studied. ( S )-2-Me-CBS-catalysed reduction of alnustone with BH₃SMe₂ gave ( R )(-)(4 E ,6 E )-1,7-diphenylhepta-4,6-dien-3-ol, a natural product. Reduction of alnustone with Na in t -BuOH at -15 °C under N₃ atm gave (_E)-1,7-diphenylhept-5- en-3-one as a Birch-type reduction product. _t-BuOK catalysed condensation of benzalacetone with propionyl chloride gave (4 Z ,6 E )-5-hydroxy-1,7-diphenylhepta-4,6-dien-3-one, a natural product. (1 E ,4 Z ,6 E )-5-Hydroxy-4-phenethyl-1,7-diphenylhepta-1,4,6-trien-3-one, a curcuminoid, was synthesized starting from pentan-2,4-dione in 3 steps. The synthesized chemical compounds were applied against 2 gram-positive bacteria ( Bacillus cereus and Arthrobacter agilis ), 4 gram-negative bacteria ( Pseudomonas aeruginosa , Xanthomonas campestris , Klebsiella oxytoca , and Helicobacter pylori ), and 1 yeast (Candida albicans) by the disc diffusion method. All of the synthesized compound exhibited different degrees of antimicrobial activity at concentrations between 20-100 μg/disc against the test organisms.

Diarylheptanoid analogues from the rhizomes of Zingiber officinale and their anti-tumour activity

Diarylheptanoid analogues from the rhizomes of Zingiber officinale and their anti-tumour activity.

Neuraminidase inhibitory diarylheptanoids from Alpinia officinarum: In vitro and molecular docking studies

Diarylheptanoids, known to be rich in the Zingiberaceae family, have been reported to have various pharmacological activities including neuraminidase (NA) inhibitory activity. In this study, to analyze the correlation between NA and diarylheptanoid, A. officinarum, belonging to the Zingiberaceae family, was selected as a natural resource. Four new compounds along with 26 known diarylheptanoids from the rhizomes of A. officinarum were isolated using various chromatographic techniques. The Structure-based virtual screening (SBVS) was performed to discover putative binding ligand and corresponding binding conformation of the isolated compounds. Among the isolated compounds, 10 compounds showed stable binding energy levels in NA. Five of these 10 potential hits showed the potent inhibitory activity through in vitro NA enzyme assay. Moreover, it can be deduced that hydrogen-bonding formation between carbonyl group of active diarylheptanoids and arginine 555 and arginine 615 of NA allowed for the most stable binding between the enzyme and docked compounds.

Dimeric Diarylheptanoids with Neuroprotective Activities from Rhizomes of Alpinia officinarum

Two novel dimeric diarylheptanoids, alpinidinoids A [(±)-1] and B (2), with two unusual coupling patterns, together with a new naturally occurring diarylheptanoid dimer possessing a rare pyridine ring linkage (alpinidinoid C, 3), were isolated from the rhizomes of Alpinia officinarum. Their structures including absolute configurations were determined by extensive spectroscopic methods and theoretical calculations. All isolates were examined for their neuroprotective activities against oxygen-glucose deprivation and reoxygenation (OGD/R) damage in primary cortical neurons. Remarkably, the dextrorotatory enantiomer of alpinidinoid A [(+)-1] significantly ameliorated OGD/R-induced neuronal apoptosis, which was dependent on the activation of the AKT/mTOR signaling pathway.

Pharmacokinetics and Tissue Distribution of Alnustone in Rats after Intravenous Administration by Liquid Chromatography-Mass Spectrometry

Alnustone, a nonphenolic diarylheptanoid, first isolated from Alnus pendula (Betulaceae), has recently received a great deal of attention due to its various beneficial pharmacological effects. However, its pharmacokinetic profile in vivo remains unclear. The purpose of this study is to establish a fast and sensitive quantification method of alnustone using liquid chromatography tandem mass spectrometry (LC-MS/MS) and evaluate the pharmacokinetic and tissue distribution profiles of alnustone in rats. The sample was precipitated with acetonitrile with 0.5% formic acid and separated on BEH C₁₈ Column. The mobile phase was composed of 0.1% formic acid in water and methanol at a flow rate of 0.3 mL/min. Alnustone and the internal standard (caffeine) were quantitatively monitored with precursor-to-product ion transitions of m/z 262.9→105.2 and m/z 195.2→138.0, respectively. The calibration curve for alnustone was linear from 1 to 2000 ng/mL. The intra- and inter-day assay precision (RSD) ranged from 1.1-9.0 % to 3.3-8.6%, respectively and the intra- and inter-day assay accuracy (RE) was between -8.2-9.7% and -10.3-9.9%, respectively. The validated method was successfully applied to the pharmacokinetic studies of alnustone in rats. After single-dose intravenous administration of alnustone (5 mg/kg), the mean peak plasma concentration (C_max) value was 7066.36 ± 820.62 ng/mL, and the mean area under the concentration-time curve (AUC_0-t) value was 6009.79 ± 567.30 ng/mL∙h. Our results demonstrated that the residence time of alnustone in vivo was not long and it eliminated quickly from the rat plasma. Meanwhile, the drug is mainly distributed in tissues with large blood flow, and the lung and liver might be the target organs for alnustone efficacy. The study will provide information for further application of alnustone.

Indole Diterpenoids from an Endophytic Penicillium sp

A chemical investigation of the endophyte Penicillium sp. (strain ZO-R1-1), isolated from roots of the medicinal plant Zingiber officinale, yielded nine new indole diterpenoids (1-9), together with 13 known congeners (10-22). The structures of the new compounds were elucidated by 1D and 2D NMR analysis in combination with HRESIMS data. The absolute configuration of the new natural products 1, 3, and 7 was determined using the TDDFT-ECD approach and confirmed for 1 by single-crystal X-ray determination through anomalous dispersion. The isolated compounds were tested for cytotoxicity against L5178Y, A2780, J82, and HEK-293 cell lines. Compound 1 was the most active metabolite toward L5178Y cells, with an IC₅₀ value of 3.6 μM, and an IC₅₀ against A2780 cells of 8.7 μM. Interestingly, 1 features a new type of indole diterpenoid scaffold with a rare 6/5/6/6/6/6/5 heterocyclic system bearing an aromatic ring C, which is suggested to be important for the cytotoxic activity of this natural product against L5278Y and A2780 cells.

Four new diarylheptanoids from Rhizoma Zingiberis

Four new diarylheptanoids, (1S, 3R, 5R, 6R)-1, 5-epoxy-3, 6 dihydroxy-1-(4-hydroxy-3, 5-dimethoxyphenyl)-7-(4-hydroxy-3-methoxyphenyl) heptane (1), (1R, 3R, 5S)-1, 5-epoxy-3-acetoxy-1-(4, 5-dihydroxy-3-methoxyphenyl)-7-(3, 4- hydroxyphenyl) heptane (2), (3R, 5S, 6R, 7S)-3, 6-epoxy-7-hydroxyl-1-(4-hydroxyphenyl)-7-(3-methoxy-4-hydroxyphenyl) heptane (3), (E)-3-keto-1-(3-methoxy-4-hydroxyphenyl)-7-(4, 5-dihydroxy-3-methoxyphenyl)-4- heptene (4), were isolated from Rhizoma Zingiberis, and their structures were determined based on HR-ESI-MS and extensive spectroscopic techniques (UV, IR, 1D-NMR and 2D-NMR). Compounds 1-4 exhibited no cytotoxicity against HepG2 cell lines.

Natural Negative Allosteric Modulators of 5-HT₃ Receptors

Chemotherapy-induced nausea and vomiting (CINV) remain the most common and devastating side-effects associated with cancer chemotherapy. In recent decades, several lines of research emphasize the importance of 5-hydroxytryptamine3 (5-HT3; serotonin) receptors in the pathogenesis and treatment of CINV. 5-HT₃ receptors are members of ligand-gated ion channels that mediate the rapid and transient membrane-depolarizing effect of 5-HT in the central and peripheral nervous system. These receptors play important roles in nausea and vomiting, as well as regulation of peristalsis and pain transmission. The development of antagonists for 5-HT₃ receptor dramatically improved the treatment of CINV in cancer patients. In fact, the most common use of 5-HT₃ receptor antagonists to date is the treatment of nausea and vomiting. In recent years, there has been an increasing tendency to use natural plant products as important therapeutic entities in the treatment of various diseases. In this article, we examined the results of earlier studies on the actions of natural compounds on the functional properties of 5-HT₃ receptors. It is likely that these natural modulators of 5-HT₃ receptors can be employed as lead structures for the synthesis of therapeutic agents for treating CINV in future clinical studies.

A review on the ethnomedicinal uses, phytochemistry and pharmacology of Alpinia officinarum Hance

ETHNOPHARMACOLOGICAL RELEVANCE

Alpinia officinarum Hance is a perennial plant that has been traditionally used for many decades to treat several ailments including inflammation, pain, stomach-ache, cold, amongst others. Pharmacological studies over the years have demonstrated remarkable bioactivities that could be further explored for development of new therapeutic agents against various ailments.

AIM OF THE STUDY

The paper critically reviewed the ethno-medicinal uses, pharmacology, and phytochemistry of A. officinarum.

METHODS

Keywords including A. officinarum and its synonyms were searched using electronic databases including ISI web of knowledge, Science direct, Scopus, PubMed, Google scholar and relevant database for Masters and Doctoral theses.

RESULTS

A. officinarum is prepared in Asia, Turkey, Morocco and Iran as a decoction, infusion or juice as a single preparation or in combination with other herbs, food or drinks for the treatment of general health problems including cold, inflammation, digestive disorders, etc. Pharmacological studies revealed the potent in vitro and in vivo bioactivities of various parts of A. officinarum that include anti-inflammatory, cytotoxicity, homeostasis, lipid regulation, antioxidant, antiviral, antimicrobial, antiosteoporosis, etc. Over 90 phytochemical constituents have been identified and isolated from A. officinarum comprising vastly of phenolic compounds especially diarylheptanoids isolated from the rhizome and considered the most active bioactive components.

CONCLUSION

In vitro and in vivo studies have confirmed the potency of A. officinarum. However, further studies are required to establish the mechanisms mediating its bioactivities in relation to the medicinal uses as well as investigating any potential toxicity for future clinical studies.

[6]-Gingerol Induces Amiloride-Sensitive Sodium Absorption in the Rat Colon via the Capsaicin Receptor TRPV1 in Colonic Mucosa

[6]-Gingerol possesses various beneficial pharmacological and therapeutic properties, including anti-carcinogenic and anti-inflammatory properties and the ability to regulate intestinal contraction. Recently, our group observed that the serosal administration of [6]-gingerol stimulated electrogenic sodium absorption in the rat colon via the capsaicin receptor, TRPV1. TRPV1 is known to be expressed in both the mucosal epithelium and the muscle layers in the colon. In the present study, we assessed whether [6]-gingerol stimulated sodium absorption via TRPV1 in the colonic mucosal epithelium. We compared the effect of [6]-gingerol on TRPV1-dependent colonic sodium absorption in the colon preparation with or without muscle layer. All experiments were performed by measuring the transmural potential difference (ΔPD) in an Ussing chamber system. [6]-Gingerol induced positive ΔPD when administered to the serosal side of the colon, and this effect was significantly larger in the colon preparation without muscle layer than in that with the muscle layer. In the colon preparation without muscle layer, the [6]-gingerol-dependent induction of ΔPD was markedly suppressed by mucosal addition of amiloride, a selective inhibitor of epithelial sodium channel. ΔPD induction by [6]-gingerol was considerably diminished by capsazepine, an inhibitor of the capsaicin receptor TRPV1, but not by AP-18, an inhibitor of TRPA1. These results suggest that [6]-gingerol induces amiloride-sensitive electrogenic sodium absorption in the rat colon via TRPV1 expressed in the colonic mucosal epithelium, and that this effect is independent of TRPV1 in the colonic muscle layer.

Acyclic Triterpenoids from Alpinia katsumadai Inhibit IL-6-Induced STAT3 Activation

The seeds of Alpinia katsumadai yielded two new acyclic triterpenoids, 2,3,6,22,23-pentahydroxy-2,6,11,15,19,23-hexamethyl-tetracosa-7,10,14,18-tetraene (3) and 2,3,6,22,23-pentahydroxy-2,10,15,19,23-hexamethyl-7-methylenetetracosa-10,14,18-triene (4), as well as two known compounds, 2,3,22,23-tertrahydroxy-2,6,10,15,19,23-hexamethyl-tetracosa-6,10,14,18-tetraene (1) and 2,3,5,22,23-pentahydroxy-2,6,10,15,19,23-hexamethyl-tetracosa-6,10,14,18-tetraene (2). The absolute configurations of 2 and 3, which were determined by means of a modified Mosher’s method, are suggested as (3R; 5S; 22R) and (3R; 22R), respectively. Compounds 1–4 inhibited IL-6-induced JAK2/STAT3 activity in a dose-dependent fashion, with IC₅₀ values of 0.67, 0.71, 2.18, and 2.99 μM. Moreover, IL-6-stimulated phosphorylation of STAT3 was significantly suppressed in U266 cells by the administration of A. katsumadai EtOH extract and Compounds 1 and 2. These results suggest that major phytochemicals, Compounds 1 and 2, obtained from A. katsumadai may be useful candidates for designing new IL-6 inhibitors as anti-inflammatory agents.

Characterization of diarylheptanoids: An emerging class of bioactive natural products

Diarylheptanoids are a class of secondary plant metabolites with a wide variety of bioactivity. Research on their phytochemistry and phytoanalysis is rapidly growing and the number of identified structures bearing the aryl-C₇-aryl skeleton is at present approaching 500. Historically, the yellow pigment curcumin has been characterized as the first diarylheptanoid and the extensive research on naturally occurring analogues is still ongoing. In this review, studies dealing with the characterization of linear and cyclic derivatives are discussed from the phytoanalytical point of view. Isolation, fractionation and purification strategies from natural sources along with their chromatographic behavior and structural characteristics are discussed. The role of various techniques used for the extraction (such as Soxhlet extraction, sonication, maceration/percolation, microwave-assisted extraction, supercritical carbon dioxide extraction); isolation (liquid-liquid extraction, column chromatographic techniques, preparative thin-layer and high-performance liquid chromatography, centrifugal partition chromatography, counter-current chromatography); separation (thin-layer chromatography, high-performance liquid chromatography, gas chromatography, capillary electrophoresis) and structural characterization (UV/Vis spectroscopy, infrared spectroscopy, X-ray crystallography, mass spectrometry, nuclear magnetic resonance spectroscopy and circular dichroism spectroscopy) are critically reviewed.

Cross-talk between 10-gingerol and its anti-cancerous potential: a recent update

Since time immortal, ginger, as an ancient herb, has been used throughout the world in foods and beverages due to its typical strong and pungent flavor. Besides its use as a spice, it also serves as an excellent source of several bioactive phenolics, including nonvolatile pungent compounds, such as gingerols, paradols, shogaols, and gingerones. Gingerols constitute key ingredients in fresh ginger, with the most abundant being 6-gingerol (6-G), 8-gingerol (8-G), and 10-gingerol (10-G). Many studies have investigated the various valuable pharmacological properties of these ingredients and experimentally verified the mechanistic aspects of their health effects; however, to date, most research on the anti-cancerous activities of gingerols have focused largely on 6-G. Thus, the present article deals with the number of recent studies that have indicated and highlighted the role of 10-G with respect to its cancer prevention attributes in particular and its anti-inflammatory, anti-oxidant, anti-microbial, and gastrointestinal tract protective potential in general. The purpose of this review is to provide an overview of all the experimentally validated health benefits of 10-G for nutraceutical applications. The various findings have warranted the further investigation of 10-G and its possible use in various cancer treatments as well as its promising role as a chemo-preventive agent.

An overview of chemical constituents from Alpinia species in the last six decades

Alpinia species is one of the most important genera of the Zingiberaceae family. Up to 2015, 544 compounds with various bioactivities were isolated, the major components are diarylheptanoids (143) and sesquiterpenoids (132).

Structure- and isoform-specific glucuronidation of six curcumin analogs

1. In the present study, we aimed to characterize the glucuronidation of six curcumin analogs (i.e. RAO-3, RAO-8, RAO-9, RAO-18, RAO-19, and RAO-23) derived from galangal using human liver microsomes (HLM) and twelve expressed UGT enzymes. 2. Formation of glucuronide was confirmed using high-resolution mass spectrometry. Single glucuronide metabolite was generated from each of six curcumin analogs. The fragmentation patterns were analyzed and were found to differ significantly between alcoholic and phenolic glucuronides. 3. All six curcumin analogs except one (RAO-23) underwent significant glucuronidation in HLM and expressed UGT enzymes. In general, the methoxy group (close to the phenolic hydroxyl group) enhanced the glucuronidation liability of the curcumin analogs. 4. UGT1A9 and UGT2B7 were primarily responsible for the glucuronidation of two alcoholic analogs (RAO-3 and RAO-18). By contrast, UGT1A9 and four UGT2Bs (UGT2B4, 2B7, 2B15 and 2B17) played important roles in conjugating three phenolic analogs (RAO-8, RAO-9, and RAO-19). Interestingly, the conjugated double bonds system (in the aliphatic chain) was crucial to the substrate selectivity of gastrointestinal UGTs (i.e. UGT1A7, 1A8 and 1A10). 5. In conclusion, glucuronidation of six curcumin analogs from galangal were structure- and isoform-specific. The knowledge should be useful in identifying a curcumin analog with improved metabolic property.

Curcuma ecalcarata - new natural source of pinocembrin and piperitenone

Phytochemical analysis of the rhizome extract of Curcuma ecalcarata, a hitherto uninvestigated south Western Ghats endemic species, resulted in the isolation and identification of the diaryl heptanoid trans, trans-1,7-diphenyl-5-hydroxy-4,6-heptadiene-3-one (1), steroid β-sitosterol (2), flavanone pinocembrin (4) and monoterpenoids piperitenone (3) and 8-hydroxy piperitone (5). HPTLC estimation of pinocembrin in the rhizome revealed the plant as a rich source of pinocembrin (0.37% dry wt.). The rhizome essential oil was isolated by hydrodistillation and analysed by GC-FID, GC-MS and (13)C NMR. Among the 30 constituents identified in the oil, monoterpenoids predominated (94.2%) followed by sesquiterpenoids (5.8%). The major compound consisting of 65.2% of the oil was isolated and identified as piperitenone (3). The study highlights the plant as a rich source of the flavanone pinocembrin and the volatile aroma compound piperitenone.

Compounds of Alpinia katsumadai as potential efflux inhibitors in Mycobacterium smegmatis

Efflux pumps are one of the well established mechanisms that contribute to antibiotic resistance in bacteria, such as mycobacteria. As a result, the identification of efflux pump inhibitors is an attractive target in antimicrobial therapy. The isolated compounds, three diarylheptanoids, trans,trans-1,7-diphenylhepta-4,6-dien-3-one (1), (5R)-trans-1,7-diphenyl-5-hydroxyhept-6-en-3-one (2), (3S,5S)-trans-1,7-diphenylhept-1-ene-3,5-diol (3) and the flavonoid pinocembrin (4), from Alpinia katsumadai, Zingiberaceae, were examined for their antimycobacterial activity and their synergistic effects with different antibiotics against M. smegmatis mc(2) 155. Furthermore, these compounds were evaluated as potential EtBr efflux inhibitors. Although they showed weak antimycobacterial activities (MIC ≥ 64 mg/L), especially compound 1 revealed a significant activity on the EtBr accumulation and efflux as well as a synergistic effect in combination with rifampicin.

Chemical constituents and their bioactivities of "Tongling White Ginger" (Zingiber officinale)

Gingerols and their corresponding dehydration products shogaols were considered as the active principles of ginger, the rhizome of the plant Zingiber officinale, for its antioxidant, anti-inflammatory, and antitumor activities. Ginger (Z. officinale) has been cultivated for thousands of years as a spice and for medicinal purposes in China. Tongling (Anhui province, China) has traditionally been regarded as an ideal cultivation place. "Tongling White Ginger" enjoys a reputation for being one of the top gingers in China for its thin white peel, tender flesh, rich juice, and flavor. In this study, we have isolated and identified two novel gingerdione dimers, bisgingerdiones A (1) and B (2); two new gingerol derivatives, (5R)-5-acetoxy-1,7-bis(4-hydroxy-3-methoxyphenyl)heptan-3-one (3) and methyl (Z)-neral acetal-[6]-gingerdiol (4); and 38 known compounds (5-42) from rhizomes of Zingiber officinale collected from Tongling, China. Their structures were elucidated by means of spectroscopic methods. Compounds 1-4 showed weak cytotoxic and anti-HIV-1 activities. Compounds 6, 8, and 26 showed inhibitory activities against human and mouse 11β-HSD1 (11β-hydroxysteroid dehydrogenases) with IC(50) values between 1.09 and 1.30 μM.

Update on the chemopreventive effects of ginger and its phytochemicals

The rhizomes of Zingiber officinale Roscoe (Zingiberaceae), commonly known as ginger, is one of the most widely used spice and condiment. It is also an integral part of many traditional medicines and has been extensively used in Chinese, Ayurvedic, Tibb-Unani, Srilankan, Arabic, and African traditional medicines, since antiquity, for many unrelated human ailments including common colds, fever, sore throats, vomiting, motion sickness, gastrointestinal complications, indigestion, constipation, arthritis, rheumatism, sprains, muscular aches, pains, cramps, hypertension, dementia, fever, infectious diseases, and helminthiasis. The putative active compounds are nonvolatile pungent principles, namely gingerols, shogaols, paradols, and zingerone. These compounds are some of the extensively studied phytochemicals and account for the antioxidant, anti-inflammatory, antiemetic, and gastroprotective activities. A number of preclinical investigations with a wide variety of assay systems and carcinogens have shown that ginger and its compounds possess chemopreventive and antineoplastic effects. A number of mechanisms have been observed to be involved in the chemopreventive effects of ginger. The cancer preventive activities of ginger are supposed to be mainly due to free radical scavenging, antioxidant pathways, alteration of gene expressions, and induction of apoptosis, all of which contribute towards decrease in tumor initiation, promotion, and progression. This review provides concise information from preclinical studies with both cell culture models and relevant animal studies by focusing on the mechanisms responsible for the chemopreventive action. The conclusion describes directions for future research to establish its activity and utility as a human cancer preventive and therapeutic drug. The above-mentioned mechanisms of ginger seem to be promising for cancer prevention; however, further clinical studies are warranted to assess the efficacy and safety of ginger.

Ondansetron in combination with gingerol suppresses cisplatin-induced pica in rats

AIM: To investigate whether ondansetron in combination with gingerol has suppressive effect on cisplatin-induced acute and delayed pica behavior in rats.

METHODS: Rats were divided randomly into blank control group, model control group, ondansetron group, gingerol group, and ondansetron plus gingerol group. Kaolin and food ingestion were recorded during 0-24 h and 48-72 h after cisplatin administration. At 72 h, the area postrema and jejunum tissue samples were taken to detect the immunoexpression of substance P by immunohistocheminstry.

RESULTS: During 0-24 h and 48-72 h after cisplatin administration, food ingestion increased significantly (t = 13.333, 15.000, 13.8333, 15.167, all P < 0.01) but kaolin ingestion decreased significantly (t = 9.122, 12.986, 8.525, 8.902, all P < 0.01) in the gingerol group and ondansetron plus gingerol group compared to the model control group. Compared to the ondansetron group, food ingestion was significantly higher in the gingerol group and ondansetron plus gingerol group (t = 8.000, 9.667, 11.500, 12.833, all P < 0.01), and kaolin ingestion was significantly lower in the ondansetron plus gingerol group (t = 2.499, 3.999, all P < 0.01). Kaolin ingestion was higher during 0-24 h (t = 1.365, P < 0.05) but lower during 48-72 h (t = 3.622, P < 0.01) in the gingerol group than in the ondansetron group. Compared to the gingerol group, kaolin ingestion decreased significantly in the ondansetron plus gingerol group during 0-24 h (t = 3.865, P < 0.01). No significant difference was noted in kaolin and food ingestion during 48-72 h between the ondansetron plus gingerol group and the gingerol group (t = 0.377, 1.333, all P > 0.05). The immunoexpression levels of substance P in the AP of gingerol group and ondansetron plus gingerol group were lower than that in the ondansetron group (t = 2.217, 2.408, all P < 0.01).

CONCLUSION: Gingerol is able to improve food ingestion and inhibit cisplatin-induced pica behavior in rats probably by restraining the immunoexpression of substance P. Ondansetron in combination gingerol is able to effectively inhibit cisplatin-induced acute and delayed pica in rats.

Naturally Occurring Diarylheptanoids

Diarylheptanoids, natural products with a 1,7-diphenylheptane structural skeleton, are mainly distributed in the roots, rhizomes and bark of Alpinia, Zingiber, Curcuma and Alnus species. They have become of interest in natural product research over the past twenty years because of their remarkable anticancer, anti-emetic, estrogenic, antimicrobial and antioxidant activity. This paper compiles all 307 naturally occurring diarylheptanoids from 46 plants as reported in 137 references with their distributions, physiological activities and 13C-NMR spectral data.

Effect of [6]-shogaol on cytosolic Ca2+ levels and proliferation in human oral cancer cells (OC2)

The effect of [6]-shogaol (1) on cytosolic free Ca(2+) concentrations ([Ca(2+)](i)) and viability has not been explored previously in oral epithelial cells. The present study has examined whether 1 alters [Ca(2+)](i) and viability in OC2 human oral cancer cells. Compound 1 at concentrations > or = 5 microM increased [Ca(2+)](i) in a concentration-dependent manner with a 50% effective concentration (EC(50)) value of 65 microM. The Ca(2+) signal was reduced substantially by removing extracellular Ca(2+). In a Ca(2+)-free medium, the 1-induced [Ca(2+)](i) elevation was mostly attenuated by depleting stored Ca(2+) with thapsigargin (an endoplasmic reticulum Ca(2+) pump inhibitor). The [Ca(2+)](i) signal was inhibited by La(3+) but not by L-type Ca(2+) channel blockers. The elevation of [Ca(2+)](i) caused by 1 in a Ca(2+)-containing medium was not affected by modulation of protein kinase C activity, but was inhibited by 82% with the phospholipase A2 inhibitor aristolochic acid I (20 microM). U73122, a selective inhibitor of phospholipase C, abolished 1-induced [Ca(2+)](i) release. At concentrations of 5-100 microM, 1 killed cells in a concentration-dependent manner. These findings suggest that [6]-shogaol induces a significant rise in [Ca(2+)](i) in oral cancer OC2 cells by causing stored Ca(2+) release from the thapsigargin-sensitive endoplasmic reticulum pool in an inositol 1,4,5-trisphosphate-dependent manner and by inducing Ca(2+) influx via a phospholipase A2- and La(3+)-sensitive pathway.

Mode of action of gingerols and shogaols on 5-HT3 receptors: binding studies, cation uptake by the receptor channel and contraction of isolated guinea-pig ileum

Ginger (rhizomes of Zingiber officinale) has been shown to exert potent anti-emetic properties, but its mode of action has not yet been elucidated. Among its active constituents, [6]-, [8]- and [10]-gingerol as well as [6]-shogaol were shown in different in vivo studies to be at least partly responsible for the drug's anti-emetic properties. In an attempt to gain more insight into the mode of action of these compounds, three different in vitro models were used to investigate their effects on 5-HT(3) receptors (serotonin receptor subtype) in more detail: [(14)C]guanidinium influx into N1E-115 cells which express 5-HT(3) receptors, isotonic contractions of the isolated guinea-pig ileum and equilibrium competition binding studies using a radioactively labeled 5-HT(3) receptor antagonist ([(3)H]GR65630) (3-(5-methyl-1H-imidazol-4-yl)-1-(1-methyl-1H-indol-3-yl)-1-propanone). All four compounds inhibited the [(14)C]guanidinium influx through 5-HT(3) receptor channels as well as contractions of the guinea-pig ileum induced by SR57227A ((4-amino)-(6-chloro-2-pyridyl)l-piperidine hydrochloride), a highly selective 5-HT(3) receptor agonist. Both effects were concentration-dependent, with the following order of potency for both models: [6]-shogaol> or =[8]-gingerol>[10]-gingerol> or =[6]-gingerol. All compounds showed also weak anticholinergic and antineurokininergic activities in the guinea-pig ileum (acetylcholine and substance P are mediators of the 5-HT(3) receptor effect). The vanilloid receptor did not seem to be involved derived from experiments using capsazepine. None of the tested ginger substances, however, was able to displace [(3)H]GR65630 from its binding site (5-HT(3) receptor) neither on intact N1E-115 cells nor on the purified membranes of HEK-293 cells over-expressing the h5-HT(3) receptor. It may be concluded that [6]-, [8]-, [10]-gingerol and [6]-shogaol exert their anti-emetic effect at least partly by acting on the 5-HT(3) receptor ion-channel complex, probably by binding to a modulatory site distinct from the serotonin binding site. This may include indirect effects via receptors in the signal cascade behind the 5-HT(3) receptor channel complex such as substance P receptors and muscarinic receptors; this needs further investigation since ginger is effective against motion sickness which is cured by some vanilloids and by anticholinergics such as scopolamine.

Radioprotection by plant products: present status and future prospects

The development of radioprotective agents has been the subject of intense research in view of their potential for use within a radiation environment, such as space exploration, radiotherapy and even nuclear war. However, no ideal, safe synthetic radioprotectors are available to date, so the search for alternative sources, including plants, has been on going for several decades. In Ayurveda, the traditional Indian system of medicine, several plants have been used to treat free radical-mediated ailments and, therefore, it is logical to expect that such plants may also render some protection against radiation damage. A systematic screening approach can provide leads to identifying potential new candidate drugs from plant sources, for mitigation of radiation injury. This article reviews some of the most promising plants, and their bioactive principles, that are widely used in traditional systems of medicine, and which have rendered significant radioprotection in both in vitro and in vivo model systems. Plants and their constituents with pharmacological activities that may be relevant to amelioration of radiation-mediated damage, including antiemetic, antiinflammatory, antioxidant, cell proliferative, wound healing and haemopoietic stimulatories are also discussed.