Dirigent isoflavene-forming PsPTS2: 3D structure, stereochemical, and kinetic characterization comparison with pterocarpan-forming PsPTS1 homolog in pea.

Pea phytoalexins (-)-maackiain and (+)-pisatin have opposite C6a/C11a configurations, but biosynthetically how this occurs is unknown. Pea dirigent-protein (DP) PsPTS2 generates 7,2'-dihydroxy-4',5'-methylenedioxyisoflav-3-ene (DMDIF), and stereoselectivity toward four possible 7,2'-dihydroxy-4',5'-methylenedioxyisoflavan-4-ol (DMDI) stereoisomers was investigated. Stereoisomer configurations were determined using NMR spectroscopy, electronic circular dichroism, and molecular orbital analyses. PsPTS2 efficiently converted cis-(3R,4R)-DMDI into DMDIF 20-fold faster than the trans-(3R,4S)-isomer. The 4R-configured substrate's near ß-axial OH orientation significantly enhanced its leaving group abilities in generating A-ring mono-quinone methide (QM), whereas 4S-isomer's α-equatorial-OH was a poorer leaving group. Docking simulations indicated that the 4R-configured ß-axial OH was closest to Asp51, whereas 4S-isomer's α-equatorial OH was further away. Neither cis-(3S,4S)- nor trans-(3S,4R)-DMDIs were substrates, even with the former having C3/C4 stereochemistry as in (+)-pisatin. PsPTS2 used cis-(3R,4R)-7,2'-dihydroxy-4'-methoxyisoflavan-4-ol [cis-(3R,4R)-DMI] and C3/C4 stereoisomers to give 2',7-dihydroxy-4'-methoxyisoflav-3-ene (DMIF). DP homologs may exist in licorice (Glycyrrhiza pallidiflora) and tree legume Bolusanthus speciosus, as DMIF occurs in both species. PsPTS1 utilized cis-(3R,4R)-DMDI to give (-)-maackiain 2200-fold more efficiently than with cis-(3R,4R)-DMI to give (-)-medicarpin. PsPTS1 also slowly converted trans-(3S,4R)-DMDI into (+)-maackiain, reflecting the better 4R configured OH leaving group. PsPTS2 and PsPTS1 provisionally provide the means to enable differing C6a and C11a configurations in (+)-pisatin and (-)-maackiain, via identical DP-engendered mono-QM bound intermediate generation, which PsPTS2 either re-aromatizes to give DMDIF or PsPTS1 intramolecularly cyclizes to afford (-)-maackiain. Substrate docking simulations using PsPTS2 and PsPTS1 indicate cis-(3R,4R)-DMDI binds in the anti-configuration in PsPTS2 to afford DMDIF, and the syn-configuration in PsPTS1 to give maackiain.

Cytotoxic leuconoxine-type diazaspiroindole alkaloids isolated from Cryptolepis dubia.

Two leuconoxine-type diazaspiroindole alkaloids, the known compound, (+)-melodinine E (1), and its new analogue, (+)-11-chloromelodinine E (2), were isolated from the stems of Cryptolepis dubia (Burm.f.) M.R. Almeida (Apocynaceae), collected in Laos. The chemical structures of these compounds were determined by analysis of their spectroscopic data and by comparison of these data with literature values, of which the molecular structure of 1 has been determined previously by analysis of its single-crystal X-ray diffraction data. The absolute configurations of 1 and 2 have been defined by their experimental and simulated electronic circular dichroism (ECD) spectroscopic data and supported by 1H and 13C NMR-based DP4+ probability analysis and specific rotation calculations. When tested against a small panel of human cancer cell lines, these two compounds exhibited selective cytotoxicity toward OVCAR3 human ovarian cancer cells.

iso-Guttiferone J and Structure Revision of Guttiferone J from Garcinia gummi-gutta: A Combined Experimental and Integrated QM/NMR Approach.

Many polyprenylated acylphloroglucinols with fascinating chemical structures and intriguing biological activities have been identified as key to phytochemicals isolated from Garcinia, Hypericum, and related genera. In the present work, two chiral, tautomeric, highly-oxygenated polyprenylated acylphloroglucinols tethered with acyl and prenyl moieties on a bicyclo[3.3.1]nonanetrione core were isolated from the 95% ethanolic extract of Garcinia gummi-gutta fruit. The structures of both compounds were elucidated based on the NMR and MS data with ambiguity in the exact position of the enol and keto functions at C-1 and C-3 of the core structure. The structures of both polyprenylated acylphloroglucinols were established as a structurally revised guttiferone J and the new iso-guttiferone J with the aid of gauge-independent atomic orbital NMR calculations, CP3 probability analyses, specific rotation calculations, and electronic circular dichroism calculations in combination with the experimental data. The structures of both compounds resemble hyperforin, a potent activator of the human pregnane X receptor. As expected, both compounds showed strong pregnane X receptor activation at 10 µM [7.1-fold (guttiferone J) and 5.0-fold (iso-guttiferone J)], explained by a molecular docking study, necessitating further in-depth investigation to substantiate the herb-drug interaction potential of G. gummi-gutta upon co-administration with pharmaceutical drugs.

Chemistry of Isoeugenol and Its Oxidation Products: Mechanism and Kinetics of Isoeugenol as a Skin Sensitizer.

Structurally similar phytochemical compounds may elicit markedly different skin sensitization responses. Eugenol and isoeugenol are natural phenylpropanoids found in various essential oils are frequently used as fragrance ingredients in consumer products due to their pleasing aromatic properties. Both compounds are also skin sensitizers with isoeugenol being a stronger sensitizer than eugenol. The most commonly accepted mechanisms for haptenation by eugenol involve formation of a quinone methide or an ortho-quinone intermediate. The mechanism for the increased skin response to isoeugenol remains elusive, although quinone methide intermediates have been proposed. The recent identification of diastereomeric 7,4'-oxyneolignans as electrophilic, thiol-depleting isoeugenol derivatives has revived interest in the possible role of elusive reactive intermediates associated with the isoeugenol's haptenation process. In the present work, integrated non-animal skin sensitization methods were performed to determine the ability of syn-7,4'-oxyneolignan to promote haptenation and activation of further molecular pathways in keratinocytes and dendritic cells, confirming it as a candidate skin sensitizer. Kinetic NMR spectroscopic studies using dansyl cysteamine (DCYA) confirmed the first ordered nature of the nucleophilic addition for the syn-7,4'-oxyneolignan. Computational studies reaffirmed the "syn" stereochemistry of the isolated 7,4'-oxyneolignans along with that of their corresponding DCYA adducts and provided evidence for the preferential stereoselectivity. A plausible rationale for isoeugenol's strong skin sensitization is proposed based on the formation of a hydroxy quinone methide as a reactive intermediate rather than the previously assumed quinone methide.

Is Baikiain in Tara Flour a Causative Agent for the Adverse Events Associated with the Recalled Frozen French Lentil & Leek Crumbles Food Product? - A Working Hypothesis.

The French Lentil & Leek Crumbles frozen food product was recently recalled due to reports of gastrointestinal issues. So far, 393 adverse illness complaints and 133 hospitalizations have been reported from consumption of this food, and the tara (Tara spinosa) protein flour ingredient is hypothesized to be responsible. A multipronged approach resulted in identification of (S)-(-)-baikiain in tara as a compound of interest due to its abundance, possible metabolic fate, and close resemblance to irreversible inhibitors of L-pipecolate oxidase. Oral administration of baikiain in ND4 mice showed a statistically significant increase in blood ALT levels and a reduction in liver GSH.

Structure-based design of novel melanin-concentrating hormone receptor-1 ligands based on saturated nitrogen-containing heterocycles.

Melanin Concentrating Hormone (MCH) receptor is a G protein-coupled receptor (GPCR) with two subtypes R1 and R2. MCH-R1 is involved in the control of energy homeostasis, feeding behavior and body weight. Many studies have proved that administration of MCH-R1 antagonists significantly reduces food intake and causes weight loss in animal models. Herein, we report the optimization of our previously reported virtual screening hits into novel MCH-R1 ligands with chiral aliphatic nitrogen-containing scaffolds. The activity was improved from the micromolar range of the initial leads to 7 nM. We also disclose the first MCH-R1 ligands based on a diazaspiro[4.5]decane nucleus with sub-micromolar activity. A potent MCH-R1 antagonist with acceptable pharmacokinetic profile could represent a new hope for the management of obesity.

Cannabinoid Receptor Type II Ligands from Sandalwood Oil and Synthetic α-Santalol Derivatives.

Bioassay-guided fractionation of the essential oil of Santalum album led to the identification of α-santalol (1) and ß-santalol (2) as new chemotypes of cannabinoid receptor type II (CB2) ligands with Ki values of 10.49 and 8.19 µM, respectively. Nine structurally new α-santalol derivatives (4a-4h and 5) were synthesized to identify more selective and potent CB2 ligands. Compound 4e with a piperazine structural moiety demonstrated a Ki value of 0.99 µM against CB2 receptor and did not show binding activity against cannabinoid receptor type I (CB1) at 10 µM. Compounds 1, 2, and 4e increased intracellular calcium influx in SH-SY5Y human neuroblastoma cells that were attenuated by CB2 antagonism or inverse agonism, supporting the results that these compounds are CB2 agonists. Molecular docking showed that 1 and 4e had similar binding poses, exhibiting a unique interaction with Thr114 within the CB2 receptor, and that the piperazine structural moiety is required for the binding affinity of 4e. A 200 ns molecular dynamics simulation of CB2 complexed with 4e confirmed the stability of the complex. This structural insight lays a foundation to further design and synthesize more potent and selective α-santalol-based CB2 ligands for drug discovery.

Molecular targets of insecticides and herbicides - Are there useful overlaps?

New insecticide modes of action are needed for insecticide resistance management strategies. The number of molecular targets of commercial herbicides and insecticides are fewer than 35 for both. Few commercial insecticide targets are found in plants, but ten targets of commercial herbicides are found in insects. For several of these commonly held targets, some compounds kill both plants and insects. For example, herbicidal inhibitors of p-hydroxyphenylpyruvate dioxygenase are effective insecticides on blood-fed insects. The glutamine synthetase-inhibiting herbicide glufosinate is insecticidal by the same mechanism of action, inhibition of glutamine synthetase. These and other examples of shared activities of commercial herbicides with insecticides through the same target site are discussed. Compounds with novel herbicide targets shared by insects that are not commercialized as pesticides (such as statins) are also discussed. Compounds that are both herbicidal and insecticidal can be used for insect pests not associated with crops or with crops made resistant to the compounds.

6-Oxofurostane and (iso)Spirostane Types of Saponins in Smilax sieboldii: UHPLC-QToF-MS/MS and GNPS-Molecular Networking Approach for the Rapid Dereplication and Biodistribution of Specialized Metabolites.

Identifying novel phytochemical secondary metabolites following classical pharmacognostic investigations is tedious and often involves repetitive chromatographic efforts. During the past decade, Ultra-High Performance Liquid Chromatography-Quadrupole Time of Flight-Tandem Mass Spectrometry (UHPLC-QToF-MS/MS), in combination with molecular networking, has been successfully demonstrated for the rapid dereplication of novel natural products in complex mixtures. As a logical application of such innovative tools in botanical research, more than 40 unique 3-oxy-, 3, 6-dioxy-, and 3, 6, 27-trioxy-steroidal saponins were identified in aerial parts and rhizomes of botanically verified Smilax sieboldii. Tandem mass diagnostic fragmentation patterns of aglycones, diosgenin, sarsasapogenin/tigogenin, or laxogenin were critical to establishing the unique nodes belonging to six groups of nineteen unknown steroidal saponins identified in S. sieboldii. Mass fragmentation analysis resulted in the identification of 6-hydroxy sapogenins, believed to be key precursors in the biogenesis of characteristic smilaxins and sieboldins, along with other saponins identified within S. sieboldii. These analytes' relative biodistribution and characteristic molecular networking profiles were established by analyzing the leaf, stem, and root/rhizome of S. sieboldii. Deducing such profiles is anticipated to aid the overall product integrity of botanical dietary supplements while avoiding tedious pharmacognostic investigations and helping identify exogenous components within the finished products.

Elderberry Extracts: Characterization of the Polyphenolic Chemical Composition, Quality Consistency, Safety, Adulteration, and Attenuation of Oxidative Stress- and Inflammation-Induced Health Disorders.

Elderberry is highly reputed for its health-improving effects. Multiple pieces of evidence indicate that the consumption of berries is linked to enhancing human health and preventing or delaying the onset of chronic medical conditions. Compared with other fruit, elderberry is a very rich source of anthocyanins (approximately 80% of the polyphenol content). These polyphenols are the principals that essentially contribute to the high antioxidant and anti-inflammatory capacities and the health benefits of elderberry fruit extract. These health effects include attenuation of cardiovascular, neurodegenerative, and inflammatory disorders, as well as anti-diabetic, anticancer, antiviral, and immuno-stimulatory effects. Sales of elderberry supplements skyrocketed to $320 million over the year 2020, according to an American Botanical Council (ABC) report, which is attributable to the purported immune-enhancing effects of elderberry. In the current review, the chemical composition of the polyphenolic content of the European elderberry (Sambucus nigra) and the American elderberry (Sambucus canadensis), as well as the analytical techniques employed to analyze, characterize, and ascertain the chemical consistency will be addressed. Further, the factors that influence the consistency of the polyphenolic chemical composition, and hence, the consistency of the health benefits of elderberry extracts will be presented. Additionally, adulteration and safety as factors contributing to consistency will be covered. The role of elderberry in enhancing human health alone with the pharmacological basis, the cellular pathways, and the molecular mechanisms underlying the observed health benefits of elderberry fruit extracts will be also reviewed.

Identification of the Putative Binding Site of a Benzimidazole Opioid (Etazene) and Its Metabolites at µ-Opioid Receptor: A Human Liver Microsomal Assay and Systematic Computational Study.

The synthetic benzimidazole opioid etazene (which has a 70-times higher analgesic activity than morphine), a recreational drug, has gained popularity as a novel psychoactive substance (NPS) on the illegal/darknet market; however, no experimental information is available at the molecular level on the binding mechanism and putative binding site of etazene and its metabolites at the µ-opioid receptor (MOR). In the present study, we investigated the metabolism of etazene in human liver microsomes using ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS). We also explored the possibilities of MOR activation by etazene and its metabolites by studying their binding mechanisms and interaction profiles at an active-state MOR model via molecular docking, binding free energy calculations, and all-atom molecular dynamics (MD) simulations. The putative metabolites of etazene were also predicted using the ADMET Predictor 10.1. The molecular docking studies and free energy calculations showed that etazene and its metabolites (M1, M2, and M5-M7) exhibited strong predicted binding affinity at MOR and showed overlapped binding orientation with MOR-bound agonist BU72, which was co-crystallized in the MOR X-ray crystal structure (PDB ID: 5C1M). MD also confirmed the stability of the MOR-etazene and MOR-M6 complexes. These results suggest that etazene and its metabolites may act as strong MOR agonists, highlighting the necessity of experimental validation. The insights from this study, such as key interactions between etazene and its metabolites and the MOR, will allow authorities to predict potential analogs and clarify the target-protein interactions associated with this illicit substance, granting advanced or rapid reactions to confiscating or banning potential emerging drugs.

Advances in the Chemistry, Analysis and Adulteration of Anthocyanin Rich-Berries and Fruits: 2000-2022.

Anthocyanins are reported to exhibit a wide variety of remedial qualities against many human disorders, including antioxidative stress, anti-inflammatory activity, amelioration of cardiovascular diseases, improvement of cognitive decline, and are touted to protect against neurodegenerative disorders. Anthocyanins are water soluble naturally occurring polyphenols containing sugar moiety and are found abundantly in colored fruits/berries. Various chromatographic (HPLC/HPTLC) and spectroscopic (IR, NMR) techniques as standalone or in hyphenated forms such as LC-MS/LC-NMR are routinely used to gauge the chemical composition and ensure the overall quality of anthocyanins in berries, fruits, and finished products. The major emphasis of the current review is to compile and disseminate various analytical methodologies on characterization, quantification, and chemical profiling of the whole array of anthocyanins in berries, and fruits within the last two decades. In addition, the factors affecting the stability of anthocyanins, including pH, light exposure, solvents, metal ions, and the presence of other substances, such as enzymes and proteins, were addressed. Several sources of anthocyanins, including berries and fruit with their botanical identity and respective yields of anthocyanins, were covered. In addition to chemical characterization, economically motivated adulteration of anthocyanin-rich fruits and berries due to increasing consumer demand will also be the subject of discussion. Finally, the health benefits and the medicinal utilities of anthocyanins were briefly discussed. A literature search was performed using electronic databases from PubMed, Science Direct, SciFinder, and Google Scholar, and the search was conducted covering the period from January 2000 to November 2022.

Development of potential anticancer agents and apoptotic inducers based on 4-aryl-4H chromene scaffold: Design, synthesis, biological evaluation and insight on their proliferation inhibition mechanism.

An array of 4-aryl-2-amino-4H chromene derivatives were designed, synthesized, and evaluated for cytotoxic activity against four cancer cell lines and two non-cancerous cell lines. The most active candidates were further screened for their in vitro anticancer activity on NCI panel of 60 human cancer cell lines where compounds 2a, 2b, 4a-2, and 2e showed promising activity against various leukemia, non-small lung, renal, prostate, and breast cancer cell lines, particularly against NCI-H522 non-small lung cancer cell line (GI50 of 0.35-0.60 µM), MCF7 breast cancer cell line (GI50 of 0.34-0.59 µM), and MDA-MB-468 breast cancer cell line (GI50 of 0.23-0.40 µM). Compound 2b was the most potent against all leukemia and prostate cancer cell lines with GI50 values (0.29-0.60 µM). Compound 2b inhibited the proliferation of MCF-7 and HepG2 cells by inducing cell cycle arrest and apopotosis. 2b downregulated the mRNA abundance of BAX, Apaf-1 and caspase-3 and upregulated BCL-2. The activities of caspase-3 and caspase-9 were declined in MCF-7 and HepG2 cells treated with compound 2b. Compounds 2b and 4a-2 inhibited tubulin polymerization, with an IC50 values of 0.92 and 1.13 µM, respectively. These findings indicate that these synthesized compounds may represent potential drug candidates to inhibit the proliferation of different types of cancer cells.

Benzoylcyclopropane Derivatives from Hypoxis hemerocallidea Corms.

Two monobenzoylcyclopropane (hypoxhemerol A (1: ) and hypoxhemeroloside G (2: )) and three dibenzoylcyclopropane (hypoxhemerol B (3: ), hypoxhemeroloside H (4: ), and hypoxhemeroloside I (5: )) derivatives were isolated from the hydro-alcoholic extract of Hypoxis hemerocallidea corms. This is the first instance where benzoylcyclopropane analogs were isolated from any natural source. Structure elucidation was mainly based on 1D- and 2D-NMR and HRESIMS data. The absolute configuration (2R, 4R) of 1: was determined via NOESY NMR and experimental and calculated ECD data analyses. Compounds 1: -5: and 11 recently reported metabolites (hypoxoside, obtuside A, interjectin, acuminoside, curcapicycloside, and hypoxhemerolosides A - F) were screened for in vitro antimicrobial activity against various bacterial and fungal strains. Curcapicycloside and acuminoside exhibited antibacterial activity against Escherichia coli with 78 and 79% inhibition at 20 µg/mL, respectively. Hypoxhemeroloside A showed mild antifungal activity against Cryptococcus neoformans with 63% inhibition at 20 µg/mL.

The Low Copy Nuclear Gene Region, Granule Bound Starch Synthase (GBSS1), as a Novel Mini-DNA Barcode for the Identification of Different Sage (Salvia) Species.

Morphological similarity within species makes the identification and authentication of Salvia species challenging, especially in dietary supplements that contain processed root or leaf powder of different sage species. In the present study, the species discriminatory power of 2 potential DNA barcode regions from the nuclear genome was evaluated in 7 medicinally important Salvia species from the family Lamiaceae. The nuclear internal transcribed spacer 2 and the exon 9 - 14 region of low copy nuclear gene WAXY coding for granule-bound starch synthase 1 were tested for their species discrimination ability using distance, phylogenetic, and BLAST-based methods. A novel 2-step PCR method with 2 different annealing temperatures was developed to achieve maximum amplification from genomic DNA. The granule-bound starch synthase 1 region showed higher amplification and sequencing success rates, higher interspecific distances, and a perfect barcode gap for the tested species compared to the nuclear internal transcribed spacer 2. Hence, these novel mini-barcodes generated from low copy nuclear gene regions (granule-bound starch synthase) that were proven to be effective barcodes for identifying 7 Salvia species have potential for identification and authentication of other Salvia species.

Bulbine natalensis (currently Bulbine latifolia) and select bulbine knipholones modulate the activity of AhR, CYP1A2, CYP2B6, and P-gp.

Bulbine natalensis, an emerging medicinal herb on the global market with androgenic properties, is often formulated in dietary supplements that promote perceived sexual enhancement. However, to date, comprehensive safety studies of B. natalensis are lacking, particularly those related to its herb-drug interaction potential. The purpose of this study was to assess the inductive and inhibitory effects of extracts and pure compounds of B. natalensis on human cytochrome P-450 isozymes in vitro. Our findings demonstrated that both water and methanolic extracts of B. natalensis as well as knipholone, bulbine-knipholone, and 6'-O-methylknipholone dose-dependently increased mRNA expression encoded by CYP2B6, CYP1A2, and ABCB1 genes. Functional analyses showed that water (60 to 2.20 µg/mL) and methanolic (30 to 3.75 µg/mL) extracts and knipholones (10 to 0.33 µM) increased CYP2B6 and CYP1A2 activity in a dose-dependent manner. Additionally, water extract (60 µg/mL), methanolic extract (30 µg/mL), and knipholone (10 µM) caused activation of the aryl hydrocarbon receptor up to 11.1 ± 0.7, 8.9 ± 0.6, and 7.1 ± 2.0-fold, respectively. Furthermore, inhibition studies revealed that methanolic extract attenuated the activity of metabolically active CYP1A2 (IC50, 22.6 ± 0.4 µg/mL) and CYP2B6 (IC50, 34.2 ± 6.6 µg/mL) proteins, whereas water extracts had no inhibitory effect on either isoform. These findings suggest that chronic consumption of B. natalensis may affect normal homeostasis of select CYPs with subsequent risks for HDIs when concomitantly ingested with conventional medications that are substrates of CYP2B6 and CYP1A2. However, more in-depth translational studies are required to validate our current findings and their clinical relevance.

Application of Microscopy in the Quality Control of Licorice Roots: Comparative Anatomy of the Roots and Rhizomes of Five Species of Glycyrrhiza.

The raw materials of "licorice root" in the commerce consist of roots and/or rhizomes (stolons) of different species of Glycyrrhiza. Licorice products and raw materials are frequently mislabeled and often have mixed, misidentified, or unidentified species and parts. This paper provides a detailed comparative analysis of the morpho-anatomies of the rhizomes and roots of five species of Glycyrrhiza, namely G. glabra, G. uralensis, G. echinata, G. inflata, and G. lepidota, by bright-field light microscopy and scanning electron microscopy. The studied species showed some similarities in their basic anatomical features due to the fact that they are phylogenetically closely related and belong to the same genus. However, differences in microscopic features such as the thickness of cork and medullary rays, pore frequency, and size of the vessels were observed. The rhizomes can readily be distinguished by the presence of a distinct pith. The roots lack a well-defined pith and instead have primary xylem in the center.

Profiling and Quantification of the Key Phytochemicals from the Drumstick Tree (Moringa oleifera) and Dietary Supplements by UHPLC-PDA-MS.

Moringa oleifera is known as a drumstick tree and is cultivated in the subtropics and tropics. It exhibits antihypertensive and antidiabetic effects. An ultra-high-performance liquid chromatography method was developed for the determination of 9 phytochemicals in M. oleifera leaves and marketed products. The efficient separation was achieved within 7 min with a temperature of 45 °C by using a C-18 column as the stationary phase and water/acetonitrile with 0.05% formic acid as the mobile phase. The method was validated for linearity, repeatability, limits of detection, and limits of quantification. The limits of detections of phenolic compounds 1:  - 9: were as low as 0.2 µg/mL. The photodiode array detector at 220 and 255 nm wavelengths was recruited for quantification. The key phytochemicals were detected in the range of 0.42 to 2.57 mg/100 mg sample weight in 13 dietary supplements. This study considers the quantitative analysis for lignans in M. oleifera for the first time. Isoquercitrin (5: ) and quercetin 3-O-(6-O-malonyl)-ß-D-glucopyranoside (6: ) predominates the leaves of M. oleifera with inherent degradable nature detected for compound 6: . Niazirin (2: ) was detected in amounts between 0.010 - 0.049 mg/100 mg while compound 1: was undetectable and potentially an artifact because of the fractionation process. The characterization and confirmation of components were achieved by liquid chromatography-electrospray ionization-mass spectrometry with extractive ion monitoring for the positive and negative ion modes. The developed and validated method is robust and rapid in the conclusive quantification of phytochemicals and authentication of the Moringa samples for quality assurance.

Forrestiacids†A and†B, Pentaterpene Inhibitors of ACL and Lipogenesis: Extending the Limits of Computational NMR Methods in the Structure Assignment of Complex Natural Products.

Forrestiacids A (1) and B (2) are a novel class of [4+2] type pentaterpenoids derived from a rearranged lanostane moiety (dienophile) and an abietane unit (diene). These unprecedented molecules were isolated using guidance by molecular ion networking (MoIN) from Pseudotsuga forrestii, an endangered member of the Asian Douglas Fir Family. The intermolecular hetero-Diels-Alder adducts feature an unusual bicyclo[2.2.2]octene ring system. Their structures were elucidated by spectroscopic analysis, GIAO NMR calculations and DP4+ probability analyses, electronic circular dichroism calculations, and X-ray diffraction analysis. This unique addition to the pentaterpene family represents the largest and the most complex molecule successfully assigned using computational approaches to predict accurately chemical shift values. Compounds 1 and 2 exhibited potent inhibitory activities (IC50 s <5 µM) of ATP-citrate lyase (ACL), a new drug target for the treatment of glycolipid metabolic disorders including hyperlipidemia. Validating this activity 1 effectively attenuated the de novo lipogenesis in HepG2 cells. These findings provide a new chemical class for developing potential therapeutic agents for ACL-related diseases with strong links to traditional medicines.

Is Isoeugenol a Prehapten? Characterization of a Thiol-Reactive Oxidative Byproduct of Isoeugenol and Potential Implications for Skin Sensitization.

Isoeugenol is widely used by the cosmetic and fragrance industries, but it also represents a known cause of skin sensitization adverse effects. Although devoid of a structural alert, isoeugenol has been classified as prehapten in virtue of the presence of a pre-Michael acceptor domain. Isoeugenol oxidation could theoretically lead to the generation of reactive toxic quinones, and photoinduced oxidative degradation of isoeugenol was reported to generate strongly thiol reactive byproducts. Nonetheless, the isoeugenol degradation product responsible for increased reactivity was found to be elusive. In the present study, an aged isoeugenol sample was subjected to reactivity-guided experiments to trap elusive thiol reactive species with a fluorescent nucleophile, viz. dansyl cysteamine (DCYA). The results herein presented demonstrate that photo-oxidation of isoeugenol led to the formation of a dimeric 7,4'-oxyneolignan with strong chemical reactivity, capable of nucleophilic substitution with thiols. The results were confirmed by isolation, structural characterization, and further NMR reactivity studies. Isoeugenol is already well-known as moderately reactive in thiol depletion assays, and was herein demonstrated to be capable of converting to more potent electrophilic species upon degradation, thus acting as a prehapten. The application of the reactivity-guided strategy described herein was shown to serve as an effective tool to investigate elusive skin sensitizers.