Showing papers on "Triterpene published in 2018"

Improved squalene production through increasing lipid contents in Saccharomyces cerevisiae.

Abstract: Squalene, a valuable acyclic triterpene, can be used as a chemical commodity for pharmacology, flavor, and biofuel industries. Microbial production of squalene has been of great interest due to its limited availability, and increasing prices extracted from animal and plant tissues. Here we report genetic perturbations that synergistically improve squalene production in Saccharomyces cerevisiae. As reported previously, overexpression of a truncated HMG-CoA reductase 1 (tHMG1) led to the accumulation 20-fold higher squalene than a parental strain. In order to further increase squalene accumulation in the tHMG1 overexpressing yeast, we introduced genetic perturbations-known to increase lipid contents in yeast-to enhance squalene accumulation as lipid body is a potential storage of squalene. Specifically, DGA1 coding for diacylglycerol acyltranferase was overexpressed to enhance lipid biosynthesis, and POX1 and PXA2 coding for acyl-CoA oxidase and a subunit of peroxisomal ABC transporter were deleted to reduce lipid β-oxidation. Simultaneous overexpression of tHMG1 and DGA1 coding for rate-limiting enzymes in the mevalonate and lipid biosynthesis pathways led to over 250-fold higher squalene accumulation than a control strain. However, deletion of POX1 and PXA2 in the tHMG1 overexpressing yeast did not improve squalene accumulation additionally. Fed-batch fermentation of the tHMG1 and DGA1 co-overexpressing yeast strain resulted in the production of squalene at a titer of 445.6 mg/L in a nitrogen-limited minimal medium. This report demonstrates that increasing storage capacity for hydrophobic compounds can enhance squalene production, suggesting that increasing lipid content is an effective strategy to overproduce a hydrophobic molecule in yeast.

Fragmentation of the main triterpene acids of apple by LC-APCI-MSn.

Abstract: In this paper, we investigated the fragmentation of the main triterpene acids of apple using an liquid chromatography atmospheric pressure chemical ionization mass spectrometry (LC-APCI-MSn ) approach and high-resolution mass spectrometry (HR-MS) (Q-TOF). Triterpenes were isolated using semipreparative high-performance liquid chromatography, and chemical structures were elucidated by HR-MS and nuclear magnetic resonance spectroscopy. Finally, compounds were used to study MSn behavior in ion trap. Isolated triterpenes present similar structures, bearing carboxyl group linked to C-17 and different substitutions. We observed significant changes in MS2 spectra, which were useful for further compound identification. The observed fragments allowed the discrimination of different derivatives, namely, pomaceic, annurcoic, euscaphic, pomolic, corosolic, maslinic, betulinic, oleanolic, and ursolic acids. The proposed method allows a rapid identification of triterpene acids, and it could be useful for the analysis of these compounds in apple fruits and in other natural sources.

Identification of novel compounds, oleanane- and ursane-type triterpene glycosides, from Trevesia palmata: their biocontrol activity against phytopathogenic fungi.

Abstract: Plants contain a number of bioactive compounds that exhibit antimicrobial activity, which can be recognized as an important source of agrochemicals for plant disease control. As part of our search for new antimicrobial agents from natural sources, we found that a crude methanol extract of Trevesia palmata exhibited a promising antifungal activity against phytopathogenic fungi, such as Magnaporthe oryzae and Botrytis cinerea. Furthermore, based on activity-guided fractionation, we isolated five antifungal compounds from the methanol extract of T. palmata: two new triterpene glycosides (TPGs), TPG1 (hederagenin-3-O-β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranoside) and TPG5 (3-O-α-L-rhamnopyranosyl asiatic acid), along with three known TPGs (TPG2 [macranthoside A], TPG3 [α-hederin], and TPG4 [ilekudinoside D]). The chemical structures of the TPGs were determined by spectroscopic analyses and by comparison with literature data. An in vitro antifungal bioassay revealed that except for TPG4 (ilekudinoside D; IC50 >256 μg/ml), the other TPGs exhibited strong antifungal activities against the rice blast pathogen M. oryzae with IC50 values ranging from 2–5 μg/ml. In particular, when the plants were treated with compound TPG1 (500 μg/ml), disease control values against rice blast, tomato grey mold, tomato late blight, and wheat leaf rust were 84, 82, 88, and 70%, respectively, compared to the non-treatment control. Considering the in vitro and in vivo antifungal activities of the TPGs and the T. palmata methanol extracts, our results suggest that T. palmata can be a useful source to develop new natural fungicides.

Distribution of Saponins in the Sea Cucumber Holothuria lessoni; the Body Wall Versus the Viscera, and Their Biological Activities

Abstract: Sea cucumbers are an important ingredient of traditional folk medicine in many Asian countries, which are well-known for their medicinal, nutraceutical, and food values due to producing an impressive range of distinctive natural bioactive compounds. Triterpene glycosides are the most abundant and prime secondary metabolites reported in this species. They possess numerous biological activities ranging from anti-tumour, wound healing, hypolipidemia, pain relieving, the improvement of nonalcoholic fatty livers, anti-hyperuricemia, the induction of bone marrow hematopoiesis, anti-hypertension, and cosmetics and anti-ageing properties. This study was designed to purify and elucidate the structure of saponin contents of the body wall of sea cucumber Holothuria lessoni and to compare the distribution of saponins of the body wall with that of the viscera. The body wall was extracted with 70% ethanol, and purified by a liquid-liquid partition chromatography, followed by isobutanol extraction. A high-performance centrifugal partition chromatography (HPCPC) was conducted on the saponin-enriched mixture to obtain saponins with a high purity. The resultant purified saponins were analyzed using MALDI-MS/MS and ESI-MS/MS. The integrated and hyphenated MS and HPCPC analyses revealed the presence of 89 saponin congeners, including 35 new and 54 known saponins, in the body wall in which the majority of glycosides are of the holostane type. As a result, and in conjunction with existing literature, the structure of four novel acetylated saponins, namely lessoniosides H, I, J, and K were characterized. The identified triterpene glycosides showed potent antifungal activities against tested fungi, but had no antibacterial effects on the bacterium Staphylococcus aureus. The presence of a wide range of saponins with potential applications is promising for cosmeceutical, medicinal, and pharmaceutical products to improve human health.

Anti-Influenza Triterpene Saponins from the Bark of Burkea africana

Abstract: In an in vitro cytopathic effect inhibition assay with the H3N2 influenza virus A/Hong Kong/68 (HK/68), the bark extract of Burkea africana was found to be a promising antiviral lead with an IC50 value of 5.5 μg/mL without noteworthy cytotoxicity in Madin Darby canine kidney cells. After several chromatographic steps, triterpene saponins of the lupane and oleanane types were identified as the bioactive principles. In total, eight new triterpene saponins (1–8) with four so far undescribed aglycone structures were isolated and characterized via HRESIMS, GC-MS, and 1D and 2D NMR spectroscopy. Their anti-influenza virus activity on HK/68 and the 2009 pandemic H1N1 strain A/Jena/8178/09 revealed the most potent effects by compounds 7 and 8, with IC50 values between 0.05 and 0.27 μM. This is the first time triterpene saponins have been reported as constituents of the investigated plant material.

Synthesis and Evaluation of Anticancer Activities of Novel C-28 Guanidine-Functionalized Triterpene Acid Derivatives.

Abstract: Triterpene acids, namely, 20,29-dihydrobetulinic acid (BA), ursolic acid (UA) and oleanolic acid (OA) were converted into C-28-amino-functionalized triterpenoids 4⁻7, 8a, 15, 18 and 20. These compounds served as precursors for the synthesis of novel guanidine-functionalized triterpene acid derivatives 9b⁻12b, 15c, 18c and 20c. The influence of the guanidine group on the antitumor properties of triterpenoids was investigated. The cytotoxicity was tested on five human tumor cell lines (Jurkat, K562, U937, HEK, and Hela), and compared with the tests on normal human fibroblasts. The antitumor activities of the most tested guanidine derivatives was lower, than that of corresponding amines, but triterpenoids with the guanidine group were less toxic towards human fibroblasts. The introduction of the tris(hydroxymethyl)aminomethane moiety into the molecules of triterpene acids markedly enhanced the cytotoxic activity of the resulting conjugates 15, 15c, 18b,c and 20b,c irrespective of the triterpene skeleton type. The dihydrobetulinic acid amine 15, its guanidinium derivative 15c and guanidinium derivatives of ursolic and oleanolic acids 18c and 20c were selected for extended biological investigations in Jurkat cells, which demonstrated that the antitumor activity of these compounds is mediated by induction of cell cycle arrest at the S-phase and apoptosis.

Triterpenes and Meroterpenes with Neuroprotective Effects from Ganoderma leucocontextum.

Abstract: Ganoderma leucocontextum is a well-known medicinal mushroom cultivated in the Tibet Plateau of China. Chemistry investigation on the fruiting bodies of this mushroom resulted in the isolation of sixteen secondary metabolites including three new lanostane triterpenes, ganoleucoins Q - S (1 - 3), as well as thirteen known compounds (4 - 16). The structures of compounds 1 - 3 were determined by NMR, MS, CD spectral analysis, and chemical derivation method. The neuroprotective effects of compounds 1 - 16 were tested on PC12 cells. Compounds 1 and 2 showed protective effects against the H2 O2 induced damage with the survival rate of 83.19 ± 0.92%, 73.37 ± 1.25% at the concentration of 200 μm, respectively. Meanwhile, compounds 1 and 2 induced neurite outgrowth at 50 - 200 μm. The results from this study suggested that G. leucocontextum and its metabolites may be potential functional food ingredients for the prevention of neurodegenerative diseases.

Triterpenoids from Euphorbia maculata and Their Anti-Inflammatory Effects.

Abstract: Euphorbia maculata is a medicinal plant of the Euphorbiaceae family, which can produce anti-inflammatory and cancer chemopreventive agents of triterpenoids. The present study reports on the bioactive triterpenoids of this plant. Two new lanostane-type triterpenoids, named (3S,4S,7S,9R)-4-methyl-3,7-dihydroxy-7(8→9) abeo-lanost-24(28)-en-8-one (1) and 24-hydroperoxylanost-7,25-dien-3β-ol (2), together with 15 known triterpene derivatives, were isolated from Euphorbia maculata. The structures of the new compounds were determined on the basis of extensive spectroscopic data (UV, MS, 1H and 13C-NMR, and 2D NMR) analysis. All tetracyclic triterpenoids (1–11) were evaluated for their anti-inflammatory effects in the test of TPA-induced inflammation (1 μg/ear) in mice. The triterpenes exhibited significant anti-inflammatory activities.

Differential Partitioning of Triterpenes and Triterpene Esters in Apple Peel

Abstract: Apple peel is a rich source of secondary metabolites, and several studies have outlined the dietary health benefits of ursane-type triterpenes in apple. Changes in triterpene metabolism have also been associated with the development of superficial scald, a postharvest apple peel browning disorder, and postharvest applications of diphenylamine and 1-methylcyclopropene. Previously, studies have generated metabolite profiles for whole apple peel or apple wax. In this study, we report separate metabolic analyses of isolated wax fractions and peel epidermis to investigate the spatial distribution of secondary metabolites in peel. In addition to examining previously reported triterpenes, we identified several unreported fatty acid esters of ursane-type triterpenes (C14–C22). All free pentacyclic triterpenes and triterpenic acids, with the exception of β-amyrin, were localized in the wax layer, along with esters of ursolic acid and uvaol. All sterols, sterol derivatives and α-amyrin esters were localized in the ...

Triterpenoids with α-glucosidase inhibitory activity and cytotoxic activity from the leaves of Akebia trifoliata

Abstract: Ten pentacyclic triterpenoids including a new multiflorane triterpene acid, 2α,3β,23-trihydroxymultiflor-7-en-28-oic acid (1), and a new lupane triterpene monoglucoside named akebiaoside C (2), were obtained from the leaves of Akebia trifoliata. Their structures were elucidated by extensive spectroscopic analysis, and they were all isolated from the leaves of A. trifoliata for the first time. These compounds, except 4 and 5, showed in vitro α-glucosidase inhibitory activity much stronger than acarbose. Especially, 2, 3, 6, 8 and 10 displayed in vitro α-glucosidase inhibitory activity with IC50 values from 0.004 to 0.081 mM, which were close or even more potent than corosolic acid (IC50 0.06 mM). Triterpenoids 1, 8 and 10 were further revealed to show moderate in vitro cytotoxic activity against human tumor A549, HeLa and HepG2 cell lines, with IC50 values ranging from 26.5 to 51.9 μM. Compound 9 selectively showed in vitro cytotoxicity toward HeLa and HepG2 cell lines, with IC50 values of 81.49 and 73.47 μM, respectively. These findings provided new data to support that the leaves of A. trifoliata are a rich source in bioactive triterpenoids highly valuable to be developed for medicinal usage.

Secondary Metabolites: Secondary Metabolic Products Consisting of C and H; C, H, and O; N, S, and P Elements; and O/N Heterocycles

Abstract: Terpenes and terpenoids, steroids and sterols, volatile oils, miscellaneous isoprenoids, phenols and phenyl propanoids, alkaloids, glycosides, bitter principles, resins, saponins, cardioactive compounds, etc., are important groups of secondary metabolites of plant origin. Terpenes and terpenoids are naturally occurring hydrocarbons, and ~2000 plant species of 60 families produce more than 55,000 terpenes and their derivatives. Terpenes are built from isoprene monomer (C5H8), and (C5H8)n. is the basic molecular formula. The oxygen-containing terpenes are called terpenoids or isoprenoids while steroids are cyclic terpenoids, and sterols are steroid alcohols. Terpenoids have significant importance in food, pharmaceutical, and cosmetic industry. Terpenoids contribute to plant essential oils (eucalyptus, lavender, thyme, and mint), flavors (cinnamon, cloves, and ginger), color (yellow—sunflowers, red—tomatoes), etc. They protect plant against predators and pests (e.g., from herbivores, insects, fungi, microorganisms, etc.), aid to pollination and dispersal of spores, and in living organisms function range from pigments and fragrances to vitamins and precursors of sex hormones. Plant sterols, including campesterol, inhibit the absorption of cholesterol in the intestines and thereby reduce LDLs or cholesterol level. Phenols or phenolics are a class of chemical compounds with a benzene nucleus supporting a hydroxyl group and range from simple substances like phenolic acids or phenols, cumarines, flavonoids, and quinines to very complex ones such as lignins and tannins. Phenol and its chemical derivatives are used in the production of detergents, phenoxy herbicides, numerous pharmaceutical drugs, and many industrial synthetic goods. Alkaloids are cyclic bitter organic compounds containing nitrogen in a negative state of oxidation having a marked physiological action on man and other animals. A large variety of organisms produce alkaloids, including bacteria, fungi, plants, and animals. Alkaloids like caffeine, ephedrine, codeine, colchicine, nicotine, pilocarpine, opium, quinine, reserpine, cocaine, psilocin morphine, atropine, berberine, vincristine, yohimbine, etc., are some common examples of drugs principles of pharmaceutical importance and often are used as recreational drugs, or in entheogenic rituals. A glycoside is a heteromolecule consisting of a non-sugar (aglycone) and a sugar part (glycone) components. The glycone may be monosaccharide or oligosaccharide, and the aglycone may be an alcohol, anthraquinone derivative, phenol, aldehyde, acid, ester, or another compound. Glycosides play numerous important roles in living organisms, and many such plant glycosides are used as medications, e.g., the active principles of digitalis, strophanthus, cascara, willow, and poplar barks are being among the most valued remedies. The bitter principles are mostly terpenoid, especially the sesquiterpene lactones, monoterpene iridoids, and the secoiridoids. Diterpene bitters are found in columbo root and white horehound, and triterpenoids are the cause of bitterness in Cucurbitaceous plants, which is due to cucurbitacins. Plant lignans are diphenolic compounds (phenylpropanoids dimers) whose structure is the union of two units of phenylpropane. Tannins are non-nitrogenous bitter plant polyphenolic compounds having a molecular weight between 500 and 3000 (gallic acid esters) and up to 20,000 (proanthocyanidins). They are non-crystallisable colloidal compounds and may be (i) hydrolyzable tannins, which consist of gallic acid or related polyhydric compounds esterified with glucose, and they are readily hydrolysed to yield the phenolic acids and the sugar; and (ii) non-hydrolyzable or condensed tannins contain only phenolic nuclei and most of such tannins are formed by the condensation of two or more flavanols, such as catechin. Pharmaceutically, tannins have antibacterial, antiviral, antiparasitic, astringent, and antiseptic properties, and may be used in the treatment of hemorrhages (constrict of blood vessels), burns (cicatrizing), diarrhea, and as an antidote for alkaloid poisoning because of their ability to precipitate alkaloids; effective against 6-hydroxydopamine-induced toxicity and also have anti-inflammatory and antiulcer activity. Quinones are cyclic organic compounds (aromatic diketones) and are found in bacteria, in certain fungi, in various higher plant forms, and in a few animals (e.g., sea urchins, aphids, lac insects, and certain scale insects). It is highly active anti-microbacterial, antifungal agent and highly toxic and fatal if swallowed, inhaled, or absorbed through the skin and widely used in medicine, herbicides, chemical reagents, dyes, and tanning agents. Saponins are amphiphilic glucoside molecules composed of hydrophilic glycoside glycone and lipophilic triterpene or steroid aglycone. Saponins have been used in medicine, foaming agents, in fire extinguishers, and fish poisons. Drugs that influence heart or drugs having an influence on the heart are cardioactive drugs. (i) Beta-adrenoceptor antagonists, (ii) calcium channel blocking drugs, and (iii) cardiac glycosides are three major classes of cardioactive drugs. Cardiac glycosides are also important in the pathogenesis and therapy of different human diseases (e.g., stroke, diabetes, neurological diseases, cancer, etc.). Cardioactive steroids are a class of animal and plant-derived compounds with a steroid nucleus and a specific inotropic, chronotropic, and dromotropic effect. Cardioactive steroids (CAS) became the mainstay of treatment for congestive heart failure and to control the ventricular response rate in atrial tachydysrhythmias. Antibiotics are produced by different groups of microorganisms like bacteria, fungi, and actinomycetes and in many cases by higher plants. Antibiotics in low concentration are capable of inhibiting the growth of microorganisms through an antimetabolic mechanism. They differ from antiseptics and disinfectants in their mode of action, chemical, and physical properties. The development of resistance among the microorganisms on prolonged contact with the drug is the present-day problems in the field of antibiotics. The microbial and plant sources from the terrestrial and marine environments are now providing natural products with antitumor activity.

Squalene synthase cloning and functional identification in wintersweet plant (Chimonanthus zhejiangensis).

Abstract: Three species of wintersweets: Chimonanthus salicifolius S. Y. Hu, Chimonanthus zhejiangensis M. C. Liu and Chimonanthus grammalus M. C. Liu are widely distributed in China. The three wintersweets belonging to the genus of Chimonanthus that can synthesize abundant terpenoids that are beneficial to human health. Their buds and leaves are traditional Chinese herb applied by the ‘She’ ethnic minority in southeast of China. Squalene is a multi-functional and ubiquitous triterpene in plants, which is biosynthesized by squalene synthase (SQS) using farnesyl diphosphate (FPP) as the substrate. The synthesis of squalene in wintersweet was not clearly. This work would provide us much help to further understand the terpene metabolism in wintersweet and its health function to people at phytochemistry and molecular levels. In this study, we identified squalene component in the extractions of leaves of three wintersweets and isolated SQS genes from leaf transcriptomes. The three SQSs were highly conservative, so CzSQS from C. zhejiangensis was just determined the enzymatic activity. The in vitro expressed CzSQS that deleted two transmembrane domains could catalyze FPP to generate squalene with the presence of NADPH and Mg2+. The squalene was one of wintersweet leaves phytochemicals. The squalene synthases of three wintersweet plants were highly conserved. The CzSQS was capable to catalyze two FPP molecules to squalene.

Phytochemical Analysis of Podospermum and Scorzonera n-Hexane Extracts and the HPLC Quantitation of Triterpenes.

Abstract: Previously tested n-hexane extracts of the Scorzonera latifolia showed promising bioactivity in vivo. Because triterpenes could account for this activity, n-hexane extracts were analyzed by HPLC to identify and quantify the triterpenes as the most abundant constituents. Other Scorzonera and Podospermum species, potentially containing triterpenic aglycones, were included in the study. An HPLC method for simultaneous determination of triterpene aglycones was therefore developed for analysis of Podospermum and Scorzonera species. n-Hexane extracts of root and aerial parts of S. latifolia, ten other Scorzonera species and two Podospermum species were studied to compare the content of triterpenes. HPLC was used for the qualitative and quantitative analysis of α-amyrin, lupeol, lupeol acetate, taraxasteryl acetate, 3-β-hydroxy-fern-7-en-6-one acetate, urs-12-en-11-one-3-acetyl, 3-β-hydroxy-fern-8-en-7-one acetate, and olean-12-en-11-one-3-acetyl. Limits of detection and quantification were determined for each compound. HPLC fingerprinting of n-hexane extracts of Podospermum and Scorzonera species revealed relatively large amounts of triterpenes in a majority of investigated taxa. Lupeol, lupeol acetate, and taraxasteryl acetate were found in a majority of the species, except S. acuminata. The presence of α-amyrin, 3β-hydroxy-fern-7-en-6-one-acetate, urs-12-en-11-one-3-acetyl, 3β-hydroxy-fern-8-en-7-one-acetate, and olean-12-en-11-one-3-acetyl was detected in varying amounts. The triterpene content could correlate with the analgesic and anti-inflammatory activity of Scorzonera, which was previously observed and Scorzonera species that have been determined to contain triterpenes in large amounts and have not yet been tested for their analgesic activity should be tested for their potential analgesic and anti-inflammatory potential. The presented HPLC method can be used for analysis of triterpene aglycones, for example dedicated to chemosystematic studies of the Scorzonerinae.

Cytotoxic Triterpenes from Salacia crassifolia and Metabolite Profiling of Celastraceae Species

Abstract: The new pentacyclic triterpene 11β-hydroxypristimerin (1), along with the known metabolites pristimerin (2), 6-oxopristimerol (3) and vitideasin (4), were isolated from a Salacia crassifolia root wood extract, following a bioassay-guided fractionation approach. Both the extract and the purified triterpenes displayed pronounced cytotoxic activity against human cancer cell lines. The NCI-60 cell line screen revealed that compound 2 was the most active, with a mean GI50 of 0.17 μM, while compound 1 had a mean GI50 of 8.7 μM. A COMPARE analysis of the screening results showed that pristimerin is likely to be the main compound responsible for the cytotoxic activity of the extract (mean GI50 of 0.3 μg·mL−1). A targeted search for pristimerin and related derivatives using LC-MS/MS revealed the presence of pristimerin (2) and 6-oxopristimerol (3) in all Celastraceae species examined and in all plant parts tested, while vitideasin (4) was only detected in the genus Salacia.

A multifunctional oxidosqualene cyclase from Tripterygium regelii that produces both α- and β-amyrin

Abstract: Tripterygium regelii is a rich source of triterpenoids, containing many types of triterpenes with high chemical diversity and interesting pharmacological properties. The cDNA of the multifunctional oxidosqualene cyclase (TrOSC, GenBank accession number: MH161182), consisting of a 2289 bp open reading frame and coding for 762 amino acids, was cloned from the stems and roots of Tripterygium regelii. Phylogenetic analysis using OSC genes from other plants suggested that TrOSC might be a mixed-amyrin synthase. The coding sequence was cloned into the expression vector pYES2 and transformed into the yeast Saccharomyces cerevisiae. The resulting products were analysed by GC-MS. Surprisingly, although it showed 76% sequence identity to lupeol synthase from Ricinus communis, TrOSC was found to be a multifunctional triterpene synthase producing both α- and β-amyrin, the precursors of ursane and oleanane type triterpenes, respectively. qRT-PCR analysis revealed that the transcript of TrOSC accumulated mainly in roots and stems. Taken together, our findings contribute to the knowledge of key genes in the pentacyclic triterpene biosynthesis pathway.

Squalene Cyclases and Cycloartenol Synthases from Polystichum polyblepharum and Six Allied Ferns

Abstract: Ferns are the most primitive of all vascular plants. One of the characteristics distinguishing them from flowering plants is its triterpene metabolism. Most cyclic triterpenes in ferns are hydrocarbons derived from the direct cyclization of squalene by squalene cyclases (SCs). Both ferns and more complex plants share sterols and biosynthetic enzymes, such as cycloartenol synthases (CASs). Polystichum belongs to Dryopteridaceae, and is one of the most species-rich of all fern genera. Several Polystichum ferns in Japan are classified as one of three possible chemotypes, based on their triterpene profiles. In this study, we describe the molecular cloning and functional characterization of cDNAs encoding a SC (PPH) and a CAS (PPX) from the type species Polystichum polyblepharum. Heterologous expression in Pichia pastoris revealed that PPH and PPX are hydroxyhopane synthase and CAS, respectively. By using the PPH and PPX sequences, we successfully isolated SC- and CAS-encoding cDNAs from six Polystichum ferns. Phylogenetic analysis, based on SCs and oxidosqualene cyclase sequences, suggested that the Polystichum subclade in the fern SC and CAS clades reflects the chemotype-but not the molecular phylogeny constructed using plastid molecular markers. These results show a possible relation between triterpenes and their biosynthetic enzymes in Polystichum.

Triterpene Acids from Frankincense and Semi-Synthetic Derivatives That Inhibit 5-Lipoxygenase and Cathepsin G

Abstract: Age-related diseases, such as osteoarthritis, Alzheimer’s disease, diabetes, and cardiovascular disease, are often associated with chronic unresolved inflammation. Neutrophils play central roles in this process by releasing tissue-degenerative proteases, such as cathepsin G, as well as pro-inflammatory leukotrienes produced by the 5-lipoxygenase (5-LO) pathway. Boswellic acids (BAs) are pentacyclic triterpene acids contained in the gum resin of the anti-inflammatory remedy frankincense that target cathepsin G and 5-LO in neutrophils, and might thus represent suitable leads for intervention with age-associated diseases that have a chronic inflammatory component. Here, we investigated whether, in addition to BAs, other triterpene acids from frankincense interfere with 5-LO and cathepsin G. We provide a comprehensive analysis of 17 natural tetra- or pentacyclic triterpene acids for suppression of 5-LO product synthesis in human neutrophils. These triterpene acids were also investigated for their direct interference with 5-LO and cathepsin G in cell-free assays. Furthermore, our studies were expanded to 10 semi-synthetic BA derivatives. Our data reveal that besides BAs, several tetra- and pentacyclic triterpene acids are effective or even superior inhibitors of 5-LO product formation in human neutrophils, and in parallel, inhibit cathepsin G. Their beneficial target profile may qualify triterpene acids as anti-inflammatory natural products and pharmacological leads for intervention with diseases related to aging.

Protein modelling of triterpene synthase genes from mangrove plants using Phyre2 and Swiss-model

Abstract: Molecular cloning of five oxidosqualene cyclases (OSC) genes from Bruguiera gymnorrhiza, Kandelia candel, and Rhizophora stylosa had previously been cloned, characterized, and encoded mono and -multi triterpene synthases. The present study analyzed protein modelling of triterpene synthase genes from mangrove using Phyre2 and Swiss-model. The diversity was noted within protein modelling of triterpene synthases using Phyre2 from sequence identity (38-43%) and residue (696-703). RsM2 was distinguishable from others for template structure; it used lanosterol synthase as a template (PDB ID: w6j.1.A). By contrast, other genes used human lanosterol synthase (1w6k.1.A). The predicted bind sites were correlated with the product of triterpene synthase, the product of BgbAS was β-amyrin, while RsM1 contained a significant amount of β-amyrin. Similarly BgLUS and KcMS, both main products was lupeol, on the other hand, RsM2 with the outcome of taraxerol. Homology modelling revealed that 696 residues of BgbAS, BgLUS, RsM1, and RsM2 (91-92% of the amino acid sequence) had been modelled with 100% confidence by the single highest scoring template using Phyre2. This coverage was higher than Swiss-model (85-90%). The present study suggested that molecular cloning of triterpene genes provides useful tools for studying the protein modelling related regulation of isoprenoids biosynthesis in mangrove forests.