New abietane and tigliane diterpenoids from the roots of Euphorbia fischeriana and their cytotoxic activities.

Three new abietane and two new tigliane diterpenoids were isolated from the roots Euphorbia fischeriana. Their structures were elucidated by spectroscopic methods and quantum chemical calculation. Compounds 4 and 5 exhibited the inhibitory activities against human cancer cells HeLa and HepG2, with IC50 ranging from 3.54 to 11.45 µM.

Rationally engineering santalene synthase to readjust the component ratio of sandalwood oil.

Plant essential oils (PEOs) are widely used in cosmetic and nutraceutical industries. The component ratios of PEOs determine their qualities. Controlling the component ratios is challenging in construction of PEO biotechnological platforms. Here, we explore the catalytic reaction pathways of both product-promiscuous and product-specific santalene synthases (i.e., SaSSy and SanSyn) by multiscale simulations. F441 of SanSyn is found as a key residue restricting the conformational dynamics of the intermediates, and thereby the direct deprotonation by the general base T298 dominantly produce α-santalene. The subsequent mutagenesis of this plastic residue leads to generation of a mutant enzyme SanSynF441V which can produce both α- and ß-santalenes. Through metabolic engineering efforts, the santalene/santalol titer reaches 704.2 mg/L and the component ratio well matches the ISO 3518:2002 standard. This study represents a paradigm of constructing biotechnological platforms of PEOs with desirable component ratios by the combination of metabolic and enzymatic engineering.

Daphnane-type diterpenoids from Euphorbia fischeriana Steud and their cytotoxic activities.

Two new daphnane-type diterpenoids fischerianin A (1) and fischerianin B (2), as well as two known ones langduin A (3) and langduin A6 (4), were isolated from the extracts of Euphorbia fischeriana Steud dry roots. Their structures including the absolute stereochemistry were determined by various spectroscopic methods and comparing their experimental and calculated CD spectra. 1 and 2 harbor a ketal group and a 9,13-oxide bridge in their C ring which is rare in daphnane-type diterpenoids. In cytotoxic assays, moderately inhibitory activities of 1-4 against human cancer cell lines (human malignant melanoma cell line, A375; human liver carcinoma cell line, HepG2; human promyelocytic leukemia cell line, HL-60; human Caucasian chronic myelogenous leukemia cell line, K562; human cervix epithelioid carcinoma cell line, HeLa) were observed, with IC50 values ranging from 5.31 to 21.46 µM.

Biotechnological production of betulinic acid and derivatives and their applications.

Betulinic acid (BA), a lupane-type triterpenoid, mainly distributes in birch plants. It has been reported that BA and its derivatives possess potent anticancer and anti-HIV activities. Commercial production of BA to date depends on phytochemical extraction and semi-synthesis from betulin (a biosynthetic precursor of BA). The biosynthetic pathway of BA has been completely revealed so far. The relevant enzymes involved in BA biosynthesis are summarized in this review. The studies on construction of biotechnological platforms for production of BA and other related triterpenoids are subsequently reviewed. The engineering strategies include overexpression of rate-limiting enzymes of triterpenoid biosynthesis, balancing flux between triterpenoid biosynthetic pathway and others, engineering endoplasmic reticulum, and improving cofactor availability. At the end, this review also attempted to provide future perspectives on potential strategies for further optimizing biosynthesis of BA and other triterpenoids in microbial hosts. KEY POINTS: • Summarizes the relevant enzymes involved in betulinic acid (BA) biosynthesis. • Highlights recent advances in biotechnological production of BA-related compounds. • Provides future perspectives on strategies for optimizing triterpenoid biosynthesis.

Identification of RoCYP01 (CYP716A155) enables construction of engineered yeast for high-yield production of betulinic acid.

Betulinic acid (BA) and its derivatives possess potent pharmacological activity against cancer and HIV. As with many phytochemicals, access to BA is limited by the requirement for laborious extraction from plant biomass where it is found in low amounts. This might be alleviated by metabolically engineering production of BA into an industrially relevant microbe such as Saccharomyces cerevisiae (yeast), which requires complete elucidation of the corresponding biosynthetic pathway. However, while cytochrome P450 enzymes (CYPs) that can oxidize lupeol into BA have been previously identified from the CYP716A subfamily, these generally do not seem to be specific to such biosynthesis and, in any case, have not been shown to enable high-yielding metabolic engineering. Here RoCYP01 (CYP716A155) was identified from the BA-producing plant Rosmarinus officinalis (rosemary) and demonstrated to effectively convert lupeol into BA, with strong correlation of its expression and BA accumulation. This was further utilized to construct a yeast strain that yields > 1 g/L of BA, providing a viable route for biotechnological production of this valuable triterpenoid.

Four limonoids from Bacillus subtilis-fermented neem seeds and their cytotoxic activity.

Four new limonoids, 7,12-dihydroxyvilasinone (1), vilasindione (2), 4-dehydroxynimbandiol (3) and azadiramide B (4), were isolated from extracts of Bacillus subtilis-fermented neem seeds. Their planar structures and relative configurations were elucidated by spectroscopic methods including UV, IR, MS and NMR, and the absolute stereochemistry was determined by comparing their experimental and calculated CD spectra. 4 is a rare salannin-class limonoid alkaloid. In cytotoxic assays, 3 showed inhibitory activity against MDA-MB-231, A375 and Hela cell lines with IC50 values of 21.45 ±â€¯5.41, 17.67 ±â€¯3.96 and 28.13 ±â€¯9.12 µM, respectively, while 4 selectively inhibited growth of MDA-MB-231 cell line with an IC50 value of 15.73 ±â€¯6.07 µM.

Limonoids from seeds of Azadirachta indica A. Juss. and their cytotoxic activity.

Four new limonoid-type nortriterpenoids, 1-detigloyl-1-O-methacryloylsalannin (1), 28-deoxo-2,3-dihydronimbolide (2), 12-acetoxy-3-O-acetyl-7-O-tigloylvilasinin (3) and 12-acetoxy-3-O-acetyl-7-O-methacryloylvilasinin (4), along with five known ones, were isolated from seeds of Azadirachta indica A. Juss. Their structures were elucidated by various spectroscopic methods, including UV, IR, MS, NMR, X-ray crystallography, quantum chemical calculation, as well as by comparison of their spectroscopic data with those reported. In the in vitro cytotoxic assay, 2 showed inhibitory activity against human breast cancer MDA-MB-231 cell line with IC50 value of 7.68±1.74 µmol/L, and 5 inhibited growth of human cervical cancer Hela cell line, melanoma A375 cell line and promyelocytic leukemia HL-60 cell line, with IC50 12.00±2.08, 17.44±2.11, and 13.95±5.74 µmol/L, respectively.

Hapalindole H Induces Apoptosis as an Inhibitor of NF-ĸB and Affects the Intrinsic Mitochondrial Pathway in PC-3 Androgen-insensitive Prostate Cancer Cells.

BACKGROUND: Prostate cancer presents the highest incidence rates among all cancers in men. Hapalindole H (Hap H), isolated from Fischerella muscicola (UTEX strain number LB1829) as part of our natural product anticancer drug discovery program, was found to be significantly active against prostate cancer cells. MATERIALS AND METHODS: In this study, Hap H was tested for nuclear factor-kappa B (NF-ĸB) inhibition and selective cytotoxic activity against different cancer cell lines. The apoptotic effect was assessed on PC-3 prostate cancer cells by fluorescence-activated cell sorting analysis. The underlying mechanism that induced apoptosis was studied and the effect of Hap H on mitochondria was evaluated and characterized using western blot and flow cytometric analysis. RESULTS: Hap H was identified as a potent NF-ĸB inhibitor (0.76 µM) with selective cytotoxicity against the PC-3 prostate cancer cell line (0.02 µM). The apoptotic effect was studied on PC-3 cells. The results showed that treatment of PC-3 cells with Hap H reduced the formation of NAD(P)H, suggesting that the function of the outer mitochondrial membrane was negatively affected. Thus, the mitochondrial transmembrane potential was assessed in Hap H treated cells. The results showed that the outer mitochondrial membrane was disrupted as an increased amount of JC-1 monomers were detected in treated cells (78.3%) when compared to untreated cells (10.1%), also suggesting that a large number of treated cells went into an apoptotic state. CONCLUSION: Hap H was found to have potent NF-ĸB p65-inhibitory activity and induced apoptosis through the intrinsic mitochondrial pathway in hormone-independent PC-3 prostate cancer cells.

Purification and characterization of an antibacterial and anti-inflammatory polypeptide from Arca subcrenata.

A polypeptide coded as PGC was isolated from Arca subcrenata muscle using ion exchange, Sephadex G-50 gel chromatography and RP-HPLC. PGC was identified to be a homogeneous compound by Native-PAGE and the purity was more than 98.9% measured by HPLC. The isoelectric point of PGC was determined to be 9.76 by IEF-PAGE. The molecular weight was determined to be 15,973.0Da by ESI-MS/MS. The conformational structure of PGC was characterized by UV-vis, FT-IR and CD spectroscopy. N terminal amino acid sequence of PGC was shown as PSVYDAAAQLTADVKKDLRDSWKVIGGDKKGNGVA by Edman degradation. The results demonstrated that there is a high degree of homology between PGC and the subunit from hemoglobin, and proposed that PGC is the depolymerized polypeptide of Hemoglobin I (HbI) from A. subcrenata. The evaluation of biological activities showed that the diameters of the inhibitory ring of PGC on Escherichia coli and Staphylococcus aureus were 14.5±0.44mm and 16.5±1.15mm, respectively. The IC50 of inhibition rate for PGC on NO production was 9.60±0.71µg/mL. Therefore, PGC might be developed as one of potential antibacterial and anti-inflammatory agents.

A novel terpenoid indole alkaloid derived from catharanthine via biotransformation by suspension-cultured cells of Catharanthus roseus.

OBJECTIVE: Although catharanthine (1) is well known as a biosynthetic precursor of the anticancer alkaloid, vinblastine, its alternative metabolic pathways are unclear. RESULTS: Biotransformation of 1 by suspension-cultured cells of Catharanthus roseus gave a new oxidative-cleavage product (2). The structure of 2 was determined as 3-hydroxy-4-imino-catharanthine by spectroscopic methods. Maximum conversion (9.75 %) of 2 was observed after 120 h adding 6 mg of 1/100 ml to 12-day-old suspension-cultured cells of C. roseus. Furthermore, qRT-PCR experiment was performed to reveal the effect of 1 on the expression of the genes in the biosynthetic pathway of TIA 1 up-regulated the transcript level of D4H whilst down-regulating the transcript levels of G10H, LAMT, GES, and IRS. CONCLUSION: A new metabolite of catharanthine, 3-hydroxy-4-imino-catharanthine, is reported.

Ganoderic acid C1 isolated from the anti-asthma formula, ASHMI™ suppresses TNF-α production by mouse macrophages and peripheral blood mononuclear cells from asthma patients.

Asthma is a heterogeneous airway inflammatory disease, which is associated with Th2 cytokine-driven inflammation and non-Th2, TNF-α mediated inflammation. Unlike Th2 mediated inflammation, TNF-α mediated asthma inflammation is generally insensitive to inhaled corticosteroids (ICS). ASHMITM, aqueous extract of three medicinal herbs-Ganoderma lucidum (G. lucidum), Sophora flavescens Ait (S. flavescens) and Glycyrrhiza uralensis Fischer (G. uralensis), showed a high safety profile and was clinically beneficial in asthma patients. It also suppresses both Th2 and TNF-α associated inflammation in murine asthma models. We previously determined that G. uralensis flavonoids are the key active compounds responsible for ASHMITM suppression of Th2 mediated inflammation. Until now, there are limited studies on anti-TNF-α compounds presented in ASHMITM. The objective of this study was to isolate and identify TNF-α inhibitory compounds in ASHMITM. Here we report that G. lucidum, but not the other two herbal extracts, S. flavescens or G. uralensis inhibited TNF-α production by murine macrophages; and that the methylene chloride (MC)-triterpenoid-enriched fraction, but not the polysaccharide-enriched fraction, contained the inhibitory compounds. Of the 15 triterpenoids isolated from the MC fraction, only ganoderic acid C1 (GAC1) significantly reduced TNF-α production by murine macrophages (RAW 264.7 cells) and peripheral blood mononuclear cells (PBMCs) from asthma patients. Inhibition was associated with down-regulation of NF-κB expression, and partial suppression of MAPK and AP-1 signaling pathways. Ganoderic acid C1 may have potential for treating TNF-α mediated inflammation in asthma and other inflammatory diseases.

Effects of Adding Vindoline and MeJA on Production of Vincristine and Vinblastine, and Transcription of their Biosynthetic Genes in the Cultured CMCs of Catharanthus roseus.

Vincristine and vinblastine were found by Liquid Chromatography-Mass Spectrometry (LC-MS) in Catharanthus roseuscambial meristem cells (CMCs) jointly treated with 0.25 mM vindoline and methyl jasmonate (MeJA), suggesting that C. roseus CMCs contain a complete set of the enzymes which are in response to convert vindoline into vincristine and vinblastine. Based on the facts that the transcript levels of vindoline-biosynthetic genes (STR, SGD and D4H) were up-regulated instead of being down-regulated by adding itself to the culture, and that the transcriptional factor ORCA3 was up-regulated simultaneously, we further confirmed that the transcription of STR, SGD, D4H was manipulated by ORCA3.

Ambiguine I Isonitrile from Fischerella ambigua Induces Caspase-Independent Cell Death in MCF-7 Hormone Dependent Breast Cancer Cells.

Ambiguine I isonitrile (AmbI) obtained from the cultured cyanobacterium Fischerella ambigua was identified as a potent NF-κB inhibitor (IC50=30 nM). The cytotoxic effect was evaluated in both HT-29 colon cancer cell line (EC50=4.35 µM) and MCF-7 breast cancer cell line (EC50=1.7 µM) using the SRB assay. In the cells treated with AmbI, an increased population of cells was detected in sub G1-phase. The apoptotic effect was associated with block in G1-phase of the cell cycle in treated cells; however, cell death was induced independently of caspase-7. The NF-κB expression of p50 and p65 units were also examined in treated cells and compared with the positive control, rocaglamide (IC50=75 nM). Moreover, the expression of mediators of the NF-κB pathway such as kinase IKKκ was studied at increasing concentrations of AmbI. The down stream effect of NF-κB inhibition and the effect on the expression of TNF-α induced ICAM-1 was evaluated. Thus, the dose-dependent and time-dependent effect of AmbI on MCF-7 cells was examined in an attempt to investigate its potential mechanism of action on inducing apoptosis.

Berberine and limonin suppress IgE production by human B cells and peripheral blood mononuclear cells from food-allergic patients.

BACKGROUND: Currently, there is no satisfactory treatment for IgE-mediated food allergy. Food Allergy Herbal Formula 2 (FAHF-2) and butanol-purified FAHF-2 (B-FAHF-2) have been shown to protect against peanut-induced anaphylaxis and inhibit IgE synthesis in a murine model. OBJECTIVE: To determine which herbs and compounds in FAHF-2 and B-FAHF-2 suppress IgE production. METHODS: The effect of FAHF-2 and B-FAHF-2 on IgE production was determined using a human B-cell line (U266). Individual compounds were isolated and identified using column chromatography, liquid chromatographic mass spectrometry, and nuclear magnetic resonance techniques. The potency of compounds on IgE suppression were investigated using U266 cells and verified using human peripheral blood mononuclear cells (n = 25) from peanut-allergic patients. Epsilon germline transcript expression was determined. Phosphorylated IκBα level was analyzed using the In-Cell Western assay. The mRNA expression of signal transducer and activator of transcription-3, T-box transcription factor TBX21, interferon-γ, forkhead box P3, GATA-binding protein 3, interleukin-10, and interleukin-5 also were analyzed using real-time polymerase chain reaction. RESULTS: FAHF-2 and B-FAHF-2 inhibited IgE production by U266 cells. B-FAHF-2 was 9 times more effective than FAHF-2. Two compounds that inhibited IgE production were isolated from Philodendron chinensis and identified as berberine and limonin. Berberine was more potent and inhibited IgE production by peripheral blood mononuclear cells by 80% at 0.62 µg/mL. Berberine significantly inhibited ε-germline transcript expression by peripheral blood mononuclear cells. Phosphorylated IκBα level was significantly suppressed and mRNA expressions of T-box transcription factor TBX21 and signal transducer and activator of transcription-3 were significantly increased by berberine. CONCLUSION: Berberine and limonin mediated IgE suppression. The mechanism by which berberine modulates ε-germline transcript expression might be through regulating the phosphorylated IκBα level and the expressions of signal transducer and activator of transcription-3 and T-box transcription factor TBX21. TRIAL REGISTRATION: Clinicaltrials.gov identifier NCT00602160.

Engineered production of fungal anticancer cyclooligomer depsipeptides in Saccharomyces cerevisiae.

Two fungal cyclooligomer depsipeptide synthetases(CODSs), BbBEAS (352 kDa) and BbBSLS (348 kDa) from Beauveria bassiana ATCC7159, were reconstituted in Saccharomyces cerevisiae BJ5464-NpgA, leading to the production of the corresponding anticancer natural products, beauvericins and bassianolide, respectively. The titers of beauvericins (33.8 ± 1.4 mg/l) and bassianolide (21.7± 0.1 mg/l) in the engineered S. cerevisiae BJ5464-NpgA strains were comparable to those in the native producer B. bassiana. Feeding D-hydroxyisovaleric acid (D-Hiv) and the corresponding L-amino acid precursors improved the production of beauvericins and bassianolide. However, the high price of D-Hiv limits its application in large-scale production of these cyclooligomer depsipeptides. Alternatively, we engineered another enzyme, ketoisovalerate reductase (KIVR) from B. bassiana, into S. cerevisiae BJ5464-NpgA for enhanced in situ synthesis of this expensive substrate. Co-expression of BbBEAS and KIVR in the yeast led to significant improvement of the production of beauvericins.The total titer of beauvericin and its congeners (beauvericins A-C) was increased to 61.7 ± 3.0 mg/l and reached 2.6-fold of that in the native producer B. bassiana ATCC7159. Supplement of L-Val at 10 mM improved the supply of ketoisovalerate, the substrate of KIVR, which consequently further increased the total titer of beauvericins to 105.8 ± 2.1 mg/l. Using this yeast system,we functionally characterized an unknown CODS from Fusarium venenatum NRRL 26139 as a beauvericin synthetase, which was named as FvBEAS. Our work thus provides a useful approach for functional reconstitution and engineering of fungal CODSs for efficient production of this family of anticancer molecules.

Specific 5-hydroxylation of piperlongumine by Beauveria bassiana ATCC 7159.

A new hydroxylated derivative was efficiently prepared by transforming the natural anti-cancer product, piperlongumine, with Beauveria bassiana ATCC 7159. Its structure was determined to be 5-hydroxylpiperlongumine on the basis of the spectroscopic data. The absolute configuration at C-5 was established as R by Mosher's method.

Butanolide derivatives from the bark of Machilus yaoshansis.

Six new butanolide derivatives with long aliphatic side chains (1-6), together with 23 known lipophilic constituents, were isolated from the bark of Machilus yaoshansis. Their structures were elucidated by spectroscopic and chemical methods. All the isolates were evaluated for cytotoxic and anti-inflammatory activities.

Yaoshanenolides A and B: new spirolactones from the bark of Machilus yaoshansis.

Two novel tricyclic spirolactones bearing long linear alkyl chains, yaoshanenolides A (1) and B (2), formed by Diels-Alder[4 + 2] cycloaddition of a molecule of each butenolide with ß-phellandrene, were isolated from the bark of Machilus yaoshansis. Their structures and absolute configurations were determined by extensive spectroscopic methods, especially 2D NMR and ECD data analysis. The proposed biosynthetic pathway is discussed. Both compounds exhibited nonselective cytotoxic activities against several human cancer cell lines.

Cucurbitane glucosides from the root of Machilus yaoshansis.

Seven new cucurbitane triterpene glucosides (1-5, 8, and 9) and five known analogues (6, 7, 10, cucurbitacin I 2-O-ß-d-glucopyranoside, and khekadaengoside K) have been isolated from an ethanol extract of roots of Machilus yaoshansis. Compounds 1 and 2 have an unusual 16,23:22,25-diepoxy unit, 4 is an uncommon cucurbitane 25-carbamate with the carbamoyl amino group attached at C-24 to form an oxazolidinone ring in the side chain, and 8 is the first example of a trinorcucurbitane derivative. The configurations in several pairs of C-24 epimeric cucurbitacins with 24,25-dihydroxy-22-one side chains were assigned, and the validity of J(23a,24) and J(23b,24) values to differentiate the configuration at C-24 in these cucurbitane derivatives is discussed. Compounds 2-4 showed in vitro activity against protein tyrosine phosphatase 1B with IC50 values of 8.63, 2.81, and 4.26 µM, respectively. Cucurbitacin E 2-O-ß-d-glucopyranoside (10) showed selective cytotoxicity against BGC-823 and A549 cancer cells with IC50 values of 4.98 and 3.20 µM, respectively.

[Liposoluble constituents from Iodes cirrhosa and their neuroprotective and potassium channel-blocking activity].

OBJECTIVE: To study the chemical constituents of Iodes cirrhosa and evaluate their bioactivity. METHOD: The compounds were isolated and purified by various kinds of column chromatography methods and their structures were determined by spectroscopic data analysis. Neuroprotective assay against serum deprivation induced SH-SYSY-JNK3 cell apoptosis was evaluated by MTr method while potassium channel-blocking activity was assayed in both non-specific and specific K+ channel-regulator screening models. RESULT: Twenty-one compounds were obtained from an EtOAc portion of an ethanolic extract of the root of I. cirrhosa. Their structures were elucidated as 1beta, 3beta-dihydroxyurs-9(11),12-diene(1), bauerenyl acetate(2),3beta-hydroxy-11-oxo-olean-12-enyl palmitate(3), 3beta-acetoxy-urs-12-ene-11-one(4), betulinic acid(5), stigmasta-5, 22-diene-3beta-ol(6), 7beta-hydroxystigmasterol(7), stigmasta-5, 22diene-3beta-ol3-O-beta-D-glucopyranoside(8),scopoletin(9),scopolin(10),clovamide(11),methyl 3,5-di-O-caffeoylquinate(12),3,5-dicaffeoylquinic acid(13),2,6-dimethoxy-1,4-benzoquinone(14), protocatechualdehyde(15), vanillin(16), protocatechuic acid(17), vanillic acid(18),caffeic acid(19),azelaic acid(20),and succinic acid(21). Compound 3,4,6,9,10,14,15,18 and 20 showed neuroprotective activities against serum deprivation induced SH-SYSY-JNK3 cell apoptosis at a concentration of 1.0 x 10(6) mol x L(1) with relative protection rates of 177%, 144%, 137%, 137%, 143%, 145%, 137%, 189%, 130%, respectivley. Compound 16 could increase DiBAC4(3) fluorescence response in both non-specific and specific K+ channel-regulator screening models at the concentration of 1.0 x 10(-5) mol x L(-1). CONCLUSION: Compound 1 was a new compound and all compounds were isolated from this genus for the first time. Compounds 3,4,6,9,10,14,15,18 and 20 showed neuroprotective activities while 16 exhibited K+ channel-blocking activity.