The leaves of a tropical plant, Mitragyna speciosa KORTH (Rubiaceae), have been traditionally used as a substitute for opium. Phytochemical studies of the constituents of the plant growing in Thailand and Malaysia have led to the isolation of several 9-methoxy-Corynanthe-type monoterpenoid indole alkaloids, including new natural products. The structures of the new compounds were elucidated by spectroscopic and/or synthetic methods. The potent opioid agonistic activities of mitragynine, the major constituent of this plant, and its analogues were found in in vitro and in vivo experiments and the mechanisms underlying the analgesic activity were clarified. The essential structural features of mitragynines, which differ from those of morphine and are responsible for the analgesic activity, were elucidated by pharmacological evaluation of the natural and synthetic derivatives. Among the mitragynine derivatives, 7-hydroxymitragynine, a minor constituent of M. speciosa, was found to exhibit potent antinociceptive activity in mice.
The leaf and bark oils of Cinnamomum verum J.S. Presl. were examined for their antifungal activity against 6 dermatophytes (Trichophyton rubrum, T. mentagrophytes, T. tonsurans, Microsporum canis, M. gypseum and M. audouini), one filamentous fungi (Aspergillus fumigatus) and 5 strains of yeasts (Candida albicans, Ca. glabrata, Ca. tropicalis, Ca. parapsilosis and Crytococcus neoformans) by using the broth microdilution method. The antifungal activities of 4 standard compounds (cinnamaldehyde, eugenol, linalool and a-terpineol) which were major constituents in the oils were also investigated in an effort to correlate the effectiveness of the oils with those of the components of the oils. The combined antifungal effect of the oils against M. canis, M. gypseum and Cr. neoformans was investigated by the checkerboard assay. Isobolograms were constructed and Fractional Inhibitory Concentrations Index (FICI) were calculated to determine the combination effects between the oils. The chemical composition of the oils was analyzed by gas chromatography (GC) and gas chromatography- mass spectrometry (GC-MS). The oils showed strong activity against all the tested fungi with Minimum Inhibition Concentration (MIC) values ranging from 0.04 to 0.31 mg/ml. Cinnamaldehyde which was the most abundant component of the bark oil of C. verum showed the strongest activity against all the fungi studied. Based on the results of the assay on standard samples, it may be that the high levels of cinnamaldehyde and eugenol in the oils and in combination with the minor components could be responsible for the high antifungal activity of the oils. The antifungal effect of the leaf and bark oils of C. verum in combination against the tested fungi was not synergistic. However, the effect was additive against M. gypseum and antagonistic against Cr. neoformans and M. canis.
Immobilized Candida rugosa lipase was used for the synthesis of citronellyl laurate from citronellol and lauric acid. Screening of different types of support (Amberlite MB-1 and Celite) for immobilization of lipase and solvent (n-hexane, n-heptane, and iso-octane) and optimization of reaction conditions, such as catalyst loading, effect of substrates molar ratio and temperature, have been studied. The maximum enzyme activity was obtained at 310 K. The immobilized C. rugosa lipase onto Amberlite MB-1 support was found to be the best support with a conversion of 89% of citronellyl laurate ester in iso-octane compared to Celite 545. Deactivation of C. rugosa lipase at 313, 318 and 323 K were observed. Ordered bi bi mechanism with dead end complex of lauric acid was found to fit the initial rate data and the kinetic parameters were obtained by non-linear regression analysis.
More than half the world's rainforest has been lost to agriculture since the Industrial Revolution. Among the most widespread tropical crops is oil palm (Elaeis guineensis): global production now exceeds 35 million tonnes per year. In Malaysia, for example, 13% of land area is now oil palm plantation, compared with 1% in 1974. There are enormous pressures to increase palm oil production for food, domestic products, and, especially, biofuels. Greater use of palm oil for biofuel production is predicated on the assumption that palm oil is an "environmentally friendly" fuel feedstock. Here we show, using measurements and models, that oil palm plantations in Malaysia directly emit more oxides of nitrogen and volatile organic compounds than rainforest. These compounds lead to the production of ground-level ozone (O(3)), an air pollutant that damages human health, plants, and materials, reduces crop productivity, and has effects on the Earth's climate. Our measurements show that, at present, O(3) concentrations do not differ significantly over rainforest and adjacent oil palm plantation landscapes. However, our model calculations predict that if concentrations of oxides of nitrogen in Borneo are allowed to reach those currently seen over rural North America and Europe, ground-level O(3) concentrations will reach 100 parts per billion (10(9)) volume (ppbv) and exceed levels known to be harmful to human health. Our study provides an early warning of the urgent need to develop policies that manage nitrogen emissions if the detrimental effects of palm oil production on air quality and climate are to be avoided.
Terpenes and terpenoids are among the key impact substances in the food and fragrance industries. Equipped with pharmacological properties and applications as ideal precursors for the biotechnological production of natural aroma chemicals, interests in these compounds have been escalating. Hence, the syntheses of new derivatives that can show improved properties are often called for. Stereoselective biotransformation offers several benefits to increase the rate of production, in terms of both the percentage yield and its enantiomeric excesses. Baker's yeast (Saccharomyces cerevisiae) is broadly used as a whole cell stereospecific reduction biocatalyst, due to its capability in reducing carbonyls and carbon-carbon double bonds, which also extends its functionality as a versatile biocatalyst in terpenoid biotransformation. This review provides some insights on the development and prospects in the reductive biotransformation of monoterpenoids and sesquiterpenoids using S. cerevisiae, with an overview of strategies to overcome the common challenges in large-scale implementation.
The essential oils from the leaves and rhizomes of Alpinia pahangensis Ridl., collected from Pahang, Peninsular Malaysia, were obtained by hydrodistillation, and their chemical compositions were determined by GC and GC/MS analyses. The major components of the rhizome oil were γ-selinene (11.60%), β-pinene (10.87%), (E,E)-farnesyl acetate (8.65%), and α-terpineol (6.38%), while those of the leaf oil were β-pinene (39.61%), α-pinene (7.55%), and limonene (4.89%). The investigation of the antimicrobial activity of the essential oils using the broth microdilution technique revealed that the rhizome oil of A. pahangensis inhibited five Staphylococcus aureus strains with minimum inhibitory concentration (MIC) values between 0.08 and 0.31 μg/μl, and four selected fungi with MIC values between 1.25 and 2.50 μg/μl.
Two poorly studied, morphologically allied Alpinia species endemic to Borneo, viz., A. ligulata and A. nieuwenhuizii, were investigated here for their rhizome essential oil. The oil compositions and antimicrobial activities were compared with those of A. galanga, a better known plant. A fair number of compounds were identified in the oils by GC-FID and GC/MS analyses, with large differences in the oil composition between the three species. The rhizome oil of A. galanga was rich in 1,8-cineole (29.8%), while those of A. ligulata and A. nieuwenhuizii were both found to be extremely rich in (E)-methyl cinnamate (36.4 and 67.8%, resp.). The three oils were screened for their antimicrobial activity against three Gram-positive and three Gram-negative bacteria and two fungal species. The efficiency of growth inhibition of Staphylococcus aureus var. aureus was found to decline in the order of A. nieuwenhuizii>A. ligulata ∼ A. galanga, while that of Escherichia coli decreased in the order of A. galanga>A. nieuwenhuzii ∼ A. ligulata. Only the A. galanga oil inhibited the other bacteria and the fungi tested.
Eucalyptus is characterized by high foliar concentrations of plant secondary metabolites with marked qualitative and quantitative variation within a single species. Secondary metabolites in eucalypts are important mediators of a diverse community of herbivores. We used a candidate gene approach to investigate genetic associations between 195 single nucleotide polymorphisms (SNPs) from 24 candidate genes and 33 traits related to secondary metabolites in the Tasmanian Blue Gum (Eucalyptus globulus). We discovered 37 significant associations (false discovery rate (FDR) Q < 0.05) across 11 candidate genes and 19 traits. The effects of SNPs on phenotypic variation were within the expected range (0.018 < r(2) < 0.061) for forest trees. Whereas most marker effects were nonadditive, two alleles from two consecutive genes in the methylerythritol phosphate pathway (MEP) showed additive effects. This study successfully links allelic variants to ecologically important phenotypes which can have a large impact on the entire community. It is one of very few studies to identify the genetic variants of a foundation tree that influences ecosystem function.
The present work aims to address the gas-phase biotransformation of geraniol into citronellol using growing cells of Saccharomyces cerevisiae (baker's yeast) in a continuous-closed-gas-loop bioreactor (CCGLB). This study revealed that the gaseous geraniol had a severe effect on the production of biomass during the growing cell biotransformation resulting in the decrease in the specific growth rate from 0.07 to 0.05 h⁻¹. The rate of reaction of the growing cell biotransformation was strongly affected by agitation and substrate flow rates. The highest citronellol concentration of 1.18 g/L and initial rate of reaction of 7.06 × 10⁻⁴ g/min g(cell) were obtained at 500 rpm and 8 L/min, respectively.
We report measurements of atmospheric composition over a tropical rainforest and over a nearby oil palm plantation in Sabah, Borneo. The primary vegetation in each of the two landscapes emits very different amounts and kinds of volatile organic compounds (VOCs), resulting in distinctive VOC fingerprints in the atmospheric boundary layer for both landscapes. VOCs over the Borneo rainforest are dominated by isoprene and its oxidation products, with a significant additional contribution from monoterpenes. Rather than consuming the main atmospheric oxidant, OH, these high concentrations of VOCs appear to maintain OH, as has been observed previously over Amazonia. The boundary-layer characteristics and mixing ratios of VOCs observed over the Borneo rainforest are different to those measured previously over Amazonia. Compared with the Bornean rainforest, air over the oil palm plantation contains much more isoprene, monoterpenes are relatively less important, and the flower scent, estragole, is prominent. Concentrations of nitrogen oxides are greater above the agro-industrial oil palm landscape than over the rainforest, and this leads to changes in some secondary pollutant mixing ratios (but not, currently, differences in ozone). Secondary organic aerosol over both landscapes shows a significant contribution from isoprene. Primary biological aerosol dominates the super-micrometre aerosol over the rainforest and is likely to be sensitive to land-use change, since the fungal source of the bioaerosol is closely linked to above-ground biodiversity.
Chemical composition, antioxidant and antimicrobial activities of the fresh leaves and stems oils of Piper caninum were investigated. A total of forty eight constituents were identified in the leaves (77.9%) and stems (87.0%) oil which were characterized by high proportions of phenylpropanoid, safrole with 17.1% for leaves and 25.5% for stems oil. Antioxidant activities were evaluated by using β-carotene/linoleic acid bleaching, DPPH radical scavenging and total phenolic content. Stems oil showed the highest inhibitory activity towards lipid peroxidation (114.9 ± 0.9%), compared to BHT (95.5 ± 0.5%), while leaves oil showed significant total phenolic content (27.4 ± 0.5 mg GA/g) equivalent to gallic acid. However, the essential oils showed weak activity towards DPPH free-radical scavenging. Evaluation of antimicrobial activity revealed that both oils exhibited strong activity against all bacteria strains with MIC values in the range 62.5 to 250 μg/mL, but weak activity against fungal strains. These findings suggest that the essential oils can be used as antioxidant and antimicrobial agents for therapeutic, nutraceutical industries and food manufactures.
Cymbopogon citratus, commonly known as lemongrass, has been shown to have antioxidant, antimicrobial and chemo-protective properties. Citral, a monoterpenoid, is the major constituent of C. citratus that gives off a lemony scent and is postulated to be responsible for most of its actions. In addition, C. citratus has been traditionally used to treat gastrointestinal discomforts, however, the scientific evidence for this is still lacking. Thus, the aim of the present study was to investigate the effect of the extracts of various parts of C. citratus (leaves, stems and roots) and citral on the visceral smooth muscle activity of rabbit ileum. The effect of the test substances were tested on the spontaneous contraction, acetylcholine (ACh)- and KCl-induced contractions. Citral at doses between 0.061 mM to 15.6 mM and the extract of leaves at doses between 0.001 mg/mL to 1 mg/mL significantly reduced the spontaneous, ACh- and KCl-induced ileal contractions. When the ileum was incubated in K(+)-rich-Ca(2+)-free Tyrode's solution, it showed only minute contractions. However, the strength of contraction was increased with the addition of increasing concentrations of CaCl(2). The presence of citral almost abolished the effect of adding CaCl(2), while the leaf extract shifted the calcium concentration-response curve to the right, suggesting a calcium antagonistic effect. These results were similar to that elicited by verapamil, a known calcium channel blocker. In addition, the spasmolytic effect of citral was observed to be reduced by the nitric oxide synthase inhibitor, L-NAME. In conclusion, citral and the leaf extract of C. citratus exhibited spasmolytic activity and it appeared that they may act as calcium antagonists. Furthermore, the relaxant effect of citral, but not that of the leaf extract may be mediated by nitric oxide suggesting the presence of other chemical components in the leaf extract other than citral.
Yeast producing alcohol dehydrogenase 1 (YADH 1) enzyme has been used as a biocatalyst for the synthesis of an optically active flavouring compound known as citronellol. However, the slow growth of yeast (Saccharomyces cerevisiae) has deterred the progress of biotransformation. The main purpose of this work is to clone the genes producing YADH1 enzyme from yeast into a faster growing bacteria, Escherichia coli. Initially, the sequence of the gene encoding this protein has been identified in the S. cerevisiae Genome Databases (SGD). The so-called Yadh1 gene sequence is located from coordinate 159548 to 160594 on chromosome XV of yeast. Based on this information, two primer sequences (Forward and Reverse) were constructed. Each of these primers will bind to either end of the Yadh1 gene. The Yadh1 gene was then amplified using Polymerase Chain Reaction (PCR) technique. The amplified Yadh 1 gene was successfully cloned into a cloning vector, TOPO TA plasmid. This plasmid also contains a gene which confers resistance to ampicillin. This recombinant
plasmid was then inserted into Escherichia coli TOP 10 using heat shock protocol at 42oC. Finally, the cloned bacteria containing the recombinant TOPO TA plasmid harbouring Yadh1 gene was able to grow on Luria Bertani (LB) media supplied with antibiotic.
NADP(+)-dependent geraniol dehydrogenase (EC 1.1.1.183) is an enzyme that catalyzes the oxidation of geraniol to geranial. Stable, highly active cell-free extract was obtained from Polygonum minus leaves using polyvinylpolypyrrolidone, Amberlite XAD-4, glycerol, 2-mercaptoethanol, thiourea, and phenylmethylsulfonylfluoride in tricine-NaOH buffer (pH 7.5). The enzyme preparation was separated into two activity peaks, geraniol-DH I and II, by DEAE-Toyopearl 650M column chromatography at pH 7.5. Both isoenzymes were purified to homogeneity in three chromatographic steps. The geraniol-DH isoenzymes were similar in molecular mass, optimal temperature, and pH, but the isoelectric point, substrate specificity, and kinetic parameters were different. The K(m) values for geraniol of geraniol-DH I and II appeared to be 0.4 mM and 0.185 mM respectively. P. minus geraniol-DHs are unusual among geraniol-DHs in view of their thermal stability and optimal temperatures, and also their high specificity for allylic alcohols and NADP(+).
Epilepsy is a neurological disorder characterized by recurrent seizures resulting from excessive abnormal electrical discharges in the brain. Medicinal plants may play an invaluable role to discover the new antiepileptic drugs. The aim of the present study was to investigate the anticonvulsant activity of α-terpineol isolated from Myristica fragrans Hountt. The α-terpineol showed a significant inhibition of the seizure episodes and spikes in absence seizures model of Genetic Absence Epilepsy Rats from Strasbourg (GAERS) rats by using electroencephalography records. It showed dose-dependent anticonvulsant activity that was comparable to the known antiepileptic drug of diazepam. It showed a rapid onset and relatively short duration of anticonvulsant effects. The present findings suggest that α-terpineol might possess antiepileptic activities against the partial seizures of human because it prevented seizures in well-established genetic absence seizure animal model of GAERS rats.
The essential oils obtained by hydrodistillation from the fresh leaf and stem of Piper porphyrophyllum N.E. Br. were analyzed by GC and GC/MS. Thirty four constituents were identified in the leaf oil, while thirty eight constituents were identified in the stems oil. The most abundant components in the leaf oil included bicyclogermacrene (14.7 %), α-copaene (13.2 %) and β-phellandrene (9.5 %) while sabinene (15.5 %), bicyclogermacrene (12.3 %) and α-copaene (8.1 %) were the main constituents in the stem oil. The evaluation of antibacterial activity by using micro-dilution method revealed that both oils were moderately active against all the Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis) and Gram-negative bacteria (Pseudomonas aeruginosa, Pseudomonas putida and Escherichia coli) with minimum inhibitory concentration (MIC) values in the range 125-1000 µg/ml.
Cymbopogon citratus has been shown to have antioxidant, antimicrobial, antispasmodic and chemo-protective properties. Citral, is the major constituent of C. citratus. This study investigated the effects of methanolic extracts of leaves (LE), stems (SE), and roots (RE) of C. citratus and citral on vascular smooth muscle and explored their possible mechanisms of action. The experiment was conducted using isolated tissue preparations, where citral, LE, SE, and RE were added separately into a tissue bath that contained aortic rings, which were pre-contracted with phenylephrine (PE). Citral, LE, and RE exhibited a dose-dependent relaxant effect on the PE-induced contractions. Citral appeared to partially act via NO as its vasorelaxant effect was attenuated by L-NAME. However, the effect of LE may involve prostacyclin as indomethacin reversed the relaxant effect of LE on the PE-induced contraction. Furthermore, citral, LE, and RE abolished the restoration of PE-induced contraction caused by the addition of increasing doses of calcium in both endothelium intact and denuded rings. These findings suggest that the relaxation effect of citral, LE, and RE is endothelium-independent and may be mainly by affecting the intracellular concentration of calcium. Citral may partially act through the NO pathway while a vasodilator prostaglandin may mediate the effect of LE.
Coriander (Coriandrum sativum L.), a herbal plant, belonging to the family Apiceae, is valued for its culinary and medicinal uses. All parts of this herb are in use as flavoring agent and/or as traditional remedies for the treatment of different disorders in the folk medicine systems of different civilizations. The plant is a potential source of lipids (rich in petroselinic acid) and an essential oil (high in linalool) isolated from the seeds and the aerial parts. Due to the presence of a multitude of bioactives, a wide array of pharmacological activities have been ascribed to different parts of this herb, which include anti-microbial, anti-oxidant, anti-diabetic, anxiolytic, anti-epileptic, anti-depressant, anti-mutagenic, anti-inflammatory, anti-dyslipidemic, anti-hypertensive, neuro-protective and diuretic. Interestingly, coriander also possessed lead-detoxifying potential. This review focuses on the medicinal uses, detailed phytochemistry, and the biological activities of this valuable herb to explore its potential uses as a functional food for the nutraceutical industry.
Extraction of lemongrass oleoresin was successfully optimised using Pressurised Liquid Extraction (PLE). Character impact compounds; neral, geranial and geraniol which constituted 72% oleoresin, were monitored during this optimisation study by using GCMSD. Based on maximum extraction of these compounds, the optimised operating conditions for PLE were a temperature of 167°C, a pressure of 1203 psi and a static time of 20.43 min. The quality of PLE extract were compared with conventional extraction methods, hydrodistillation and Soxhlet extraction. The proposed method was found to be better in term of quantity of the targeted character impact compounds.
Presently, functional foods and nutraceuticals are gaining immense importance in the prevention of various maladies through dietary regimen module. Consumption of fruits and vegetables based diet has pursuit a range of bioactive components, especially phytochemicals targeting life threatening ailments. In this context, lycopene is an extensively studied antioxidant potentially present in watermelon, tomato, pink guava etc. Watermelon is one of the unique sources having readily available cis-isomeric lycopene. The distinctive aroma of watermelon is imparted by medium- and short-chain fatty acids along with geranial, ß-ionone and neral. Its consumption has been escalated owing to rich nutritional profile and allied health benefits. It is effective in reducing the extent of cancer insurgence, cardiovascular disorders, diabetes and macular diseases. The structural characteristics, physiochemical properties and therapeutic effects of lycopene are the limelight of the manuscript. However, further research investigations are still needed to address the health enhancing potential of watermelon lycopene.