A magnetic beads-based ligand fishing method for rapid discovery of monoterpene indoles as monoamine oxidase A inhibitors from Hunteria zeylanica.

In this study, a novel magnetic bead-based ligand fishing method was developed for rapid discovery of monoterpene indoles as monoamine oxidase A inhibitors from natural products. In order to improve the screening efficiency, two different magnetic beads, i.e. amine and carboxyl terminated magnetic beads, were comprehensively compared in terms of their ability to immobilize monoamine oxidase A (MAOA), biocatalytic activity and specific adsorption rates for affinity ligands. Carboxyl terminated magnetic beads performed better for MAOA immobilization and demonstrated superior performance in ligand fishing. The MAOA immobilized magnetic beads were applied to screen novel monoamine oxidase inhibitors in an alkaloid-rich plant, Hunteria zeylanica. Twelve MAOA affinity ligands were screened out, and ten of them were identified as monoterpene indole alkaloids by HPLC-Obitrap-MS/MS. Among them, six ligands, namely geissoschizol, vobasinol, yohimbol, dihydrocorynanthenol, eburnamine and (+)-isoeburnamine which exhibited inhibitory activity against MAOA with low IC50 values. To further explore their inhibitory mechanism, enzyme kinetic analysis and molecular docking studies were conducted.

Paeoniflorigenone regulates apoptosis, autophagy, and necroptosis to induce anti-cancer bioactivities in human head and neck squamous cell carcinomas.

ETHNOPHARMACOLOGICAL RELEVANCE: Paonia suffruticosa Andr. belonging to the family Paeoniaceae and has been used as a medicinal plant in Asian countries including China, Korea, and Japan. The roots of P. suffruticosa has been used in traditional medicine in various diseases including cancer and cardiovascular, female genital, and inflammatory diseases. AIM OF THE STUDY: Head and neck squamous cell carcinomas (HNSCCs) pathologically account for 90% of all head and neck cancers. However, effective targeted therapies for HNSCCs are insufficient and the prognosis is very poor, especially in patients with metastatic HNSCCs. To overcome the current limitations of available therapies for HNSCCs, pathological approaches using natural compounds are attracting attention. Our study aimed to demonstrate the anti-cancer effects of paeoniflorigenone (Paeo, 98.9% purity) isolated from the root bark of P. suffruticosa. MATERIALS AND METHODS: Our scientific methodology was performed as follows: cytotoxicity, morphological changes, and apototic DNA fragmentation were analyzed using MTT, light microscopy, and TUNEL assays. Protein expression, apoptosis, necroptosis, and autophagy were analyzed using Western blot and immunofluorescence assays. Cell migration and invasion were analyzed using wound healing and Boyden chamber assays. RESULTS: We demonstrated that Paeo significantly reduced cell proliferation and cell division, leading to caspase-dependent apoptotic cell death in human YD-10B HNSCC cells. This result was associated with PI3K/AKT/mTOR/p70S6K signaling in these cells. In addition, we investigated other programmed cell death mechanisms associated with apoptosis and found that Paeo inhibited necroptosis via dephosphorylation of key necroptotic proteins (RIP and MLKL), whereas Paeo induced autophagy via increased LC3I/II expression and autophagosome formation in human YD-10B HNSCC cells. The anti-metastatic effects of Paeo significantly suppressed cell migration and invasion in human YD-10B HNSCC cells. CONCLUSION: Overall, our results demonstrated that the bioactive compound, Paeo, exhibited anti-cancer bioactivities in human YD-10B HNSCC cells, suggesting that Paeo may be an attractive pathological approach for patients with human HNSCCs.

New monoterpenoids from the stigmas of Crocus sativus.

One new compound, crocusatin M (1), and three new glycosidic compounds, crocusatins N-P (2-4), along with nine known compounds were isolated from the dried stigmas of Crocus sativus. The structures of new compounds were elucidated on the basis of spectroscopic analysis, and the absolute configurations of 1, 2, and 3 were unambiguously assigned by the comparison of experimental and calculated ECD data. This is the first report of the isolation of 4 with the HMG moiety from the genus Crocus. Compounds 1 and 4 exhibited weak anti-inflammatory activities on inhibiting lipopolysaccharide (LPS)-induced NO production.

Optimization of SPME-Arrow-GC/MS Method for Determination of Free and Bound Volatile Organic Compounds from Grape Skins.

(1) Background: Solid phase microextraction (SPME)-Arrow is a new extraction technology recently employed in the analysis of volatiles in food materials. Grape volatile organic compounds (VOC) have a crucial role in the winemaking industry due to their sensory characteristics of wine.; (2) Methods: Box-Behnken experimental design and response surface methodology were used to optimise SPME-Arrow conditions (extraction temperature, incubation time, exposure time, desorption time). Analyzed VOCs were free VOCs directly from grape skins and bound VOCs released from grape skins by acid hydrolysis.; (3) Results: The most significant factors were extraction temperature and exposure time for both free and bound VOCs. For both factors, an increase in their values positively affected the extraction efficiency for almost all classes of VOCs. For free VOCs, the optimum extraction conditions are: extraction temperature 60 °C, incubation time 20 min, exposure time 49 min, and desorption time 7 min, while for the bound VOCs are: extraction temperature 60 °C, incubation time 20 min, exposure time 60 min, desorption time 7 min.; (4) Conclusions: Application of the optimized method provides a powerful tool in the analysis of major classes of volatile organic compounds from grape skins, which can be applied to a large number of samples.

Essential Oils from Bolivia. XV. Herzogole, an Original Monoterpene Benzodioxole from an Essential Oil from Pentacalia herzogii (Cabrera) Cuatrec.

Over 15 years, with the support of a Canadian funding agency, the Universidad Mayor de San Simón, in Bolivia, undertook a large survey of aromatic plants of the South American country. More than a hundred species were studied under various aspects, including the production and characterization of essential oils. As part of this survey, the chemical composition of an essential oil sample obtained from Pentacalia herzogii (Asteraceae) growing wild in the High Valley region of the department of Cochabamba was determined by a combination of GC and GC-MS measurements. α-Pinene was the main constituent of this essential oil (34%), accompanied by limonene (22%) and germacrene D (7.5%) as well as an important fraction of methoxylated monoterpenoids. They were mainly isomers of thymol methyl ether, accounting for 13% of the chromatogram. A new quantitatively important compound (9%) was identified through NMR and chemical synthesis as 4-isopropyl-6-methylbenzo[d][1,3]dioxole, and designated herzogole, alongside the minor related compound 1-isopropyl-2,3-dimethoxy-5-methylbenzene. The monoterpene benzodioxole featured a distinctive green-phenolic aroma which could raise interest for fragrance use. Since these compounds were not known naturally, a biosynthetic mechanism of their formation was proposed and put in perspective to illustrate the metabolic originality of P. herzogii.

(±)-Caryopterisines A and B, dimeric monoterpene alkaloids with unprecedented 6/5/5/5/6 pentacyclic rings scaffold from Caryopteris glutinosa.

(±)-Caryopterisines A (1) and B (2) featuring an unprecedented 6/5/5/5/6 pentacyclic rings system were isolated from Caryopteris glutinosa. The structures were determined by spectroscopic and X-ray crystallographic data analyses as well as theoretical calculations. Chiral HPLC resolution of both racemic 1 and 2 afforded their corresponding enantiotropic enantiomers. A plausible biogenesis for 1 and 2 may be originated from Diels-Alder reaction between pyridine-containing oxerine derivatives. The enantiotropic conversion mechanism of the enantiomers was demonstrated by H-D exchange and 18O incorporation studies. Compounds 1 and 2 showed moderate inhibition of estrogen E2 biosynthesis in human ovarian granulosa-like KGN cells. These two alkaloids reduced kynurenine biosynthesis at moderate level via inhibition of indoleamine 2,3-dioxygenase. Alkaloid 2 exhibited moderate inhibition of the release of interleukin-1ß.

A New Monoterpene from the Rhizomes of Alpinia galanga and Its Anti-Vpr Activity.

A new menthane-type monoterpene, alpigalanol (1), together with four known terpenes (2-5) were isolated from the ethyl acetate soluble fraction of the 70 % ethanol extract of the Alpinia galanga rhizomes. The structure of 1 was determined by spectroscopic analyses, including 1D- and 2D-NMR. The extract of the A. galanga rhizomes and all isolated compounds (1-5) possessed Vpr inhibitory activities against the TREx-HeLa-Vpr cells at a concentration of 1.25 µM without showing any cytotoxicity.

Alstoscholarisine K, an Antimicrobial Indole from Gall-Induced Leaves of Alstonia scholaris.

Alstoscholarisine K, an indole alkaloid with eight chiral carbons and featuring a novel 6/5/6/6/6/6/6/5 octacyclic architecture, was found to be specific to the gall-infected leaves of Alstonia scholaris. Its structure was elucidated by spectroscopy, computational analysis, and single-crystal X-ray diffraction. The unusual highly fused cage-like pyrrolo[1,2-a]pyrimidine structure with an additional -C4N unit is possibly derived from a combination of monoterpenoid indole and polyamine pathways. The fascinating compound exhibited significant antibacterial bioactivities by targeting cell membranes.

Limonene from Agastache mexicana essential oil produces antinociceptive effects, gastrointestinal protection and improves experimental ulcerative colitis.

ETHNOPHARMACOLOGY RELEVANCE: Agastache mexicana is a popular plant of great demand in folk medicine, essentially due to its calming properties and for alleviating arthritic, muscular and abdominal pain. Despite its spectrum for pain relief, pharmacological studies of its bioactive constituents have been barely investigated. AIM OF THE STUDY: To evaluate protective properties of the A. mexicana and bioactive compounds improving pathological gastrointestinal conditions in rodents. MATERIAL AND METHODS: Different doses of the essential oil of A. mexicana ssp. mexicana and ssp. xolocotziana (30-562.2 mg/kg, i.p.) and individual monoterpenes (3-300 mg/kg, i.p.) were evaluated in an abdominal pain model. The most active monoterpene limonene and sulfasalazine (reference drug, 100 mg/kg, p.o.) were also evaluated in the oxazolone-induced colitis model using an oral gavage, where some inflammatory cytokines were analyzed by enzyme-linked immunosorbent assays. Finally, colonic histological assessment and gastroprotection in the absolute ethanol-induced ulcer model were explored. RESULTS: Our results demonstrated that the essential oil of both subspecies produced a significant reduction in the abdominal writhes, where monoterpenes limonene and pulegone were partially responsible bioactive metabolites. Limonene showed the major antinociceptive efficacy in the writhing test. It also significantly decreased hyperalgesia, pathological biomarkers, and colonic inflammatory cytokines in the oxazolone-induced colitis model, as well as prevention in gastric damage. CONCLUSIONS: Present results provide scientific evidence to reinforce the use of A. mexicana in the traditional medicine for gastrointestinal conditions, mainly related to pain and inflammation, demonstrating the potential of monoterpenes as natural products in the therapeutics of gastrointestinal affections such as ulcer, colitis, and abdominal pain.

Characterizing the Volatile and Sensory Profiles, and Sugar Content of Beeswax, Beebread, Bee Pollen, and Honey.

Bee products are a well-known remedy against numerous diseases. However, from the consumers' perspective, it is essential to define factors that can affect their sensory acceptance. This investigation aimed to evaluate the volatile and sensory profiles, and sugar composition of beeswax, beebread, pollen, and honey. According to the HS-SPME/GC-MS results, 20 volatiles were identified in beeswax and honey, then 32 in beebread, and 33 in pollen. Alkanes were found to dominate in beeswax, beebread, and pollen, while aldehydes and monoterpenes in honey. In the case of sugars, a higher content of fructose was determined in beebread, bee pollen, and honey, whereas the highest content of glucose was assayed in beeswax. In the QDA, the highest aroma intensity characterized as honey-like and sweet was found in honey, while the acid aroma was typical of beebread. Other odor descriptors, including waxy, pungent, and plant-based aromas were noted only in beeswax, honey, and pollen, respectively.

Monoterpene indole alkaloids from the roots of Bousigonia mekongensis and their anti-diabetic nephropathy activity.

Four new monoterpene indole alkaloids (1-4) together with six known alkaloids (5-10) were isolated from the roots of Bousigonia mekongensis. Compounds 3 and 4 were the first examples of condylocarpan-adenine type alkaloids obtained from natural plant resource. Their structures were elucidated on the basis of spectroscopic data. All compounds were evaluated for their inhibiting glucose-induced mesanginal cell proliferation and protecting high glucose-evoked podocyte injury activities. (-)-demethoxycarbonyldihydrogambirtannine (5) can significantly antagonize glucose-induced podocyte injury with EC50 value of 6.5 ± 1.2 µM.

Chemical Constituents from Staminate Flowers of Eucommia ulmoides Oliver and Their Anti-Inflammation Activity in Vitro.

Three new monoterpenoids, named eucomylides A-C (1-3), along with six known compounds (4-9) were isolated from the staminate flowers of Eucommia ulmoides Oliver. The structures were elucidated by extensive analyses of spectroscopic methods, and their absolute configurations were established by time-dependent density functional theory electronic circular dichroism (TDDFT ECD) calculation. All the compounds along with previously isolated components (10-14) were tested for their anti-inflammatory effects. Two iridoid glycosides (11 and 12) and a flavonoid glycoside (14) showed potent suppressive effects on nitric oxide (NO) production in RAW 264.7 cells, with IC50 values ranging from 17.11 to 22.26 µM.

Bioactive monoterpene phenol dimers from the fruits of Psoralea corylifolia L.

Nine undescribed monoterpene phenol dimers, bisbakuchiols D-L (1-9), were isolated from the fruits of Psoralea corylifolia L. Their structures were elucidated based on extensive spectral analysis. The absolute configurations of 1-9 were specified by experimental and quantum chemical calculations of ECD spectra, and that of 1 was further established by X-ray diffraction analysis using Cu Kα radiation. Bisbakuchiols (1-4) were composed of two bakuchiols, one of which was cyclized via a C-7'/ C-12' single bond to form a six-member ring, and connect to each other by C-4-O-C-13' bonds. Bisbakuchiols (7-9) had a pyran ring by linkage of C-8-O-C-12. In the enzyme assay, compounds 5 and 9 exhibited significant PTP1B inhibitory activities with IC50 values of 0.69 and 0.73 µM, and compounds 1 and 3 showed moderate PTP1B inhibitory activities. Furthermore, a molecular docking simulation of PTP1B and active compounds 5 and 9 showed that these active compounds possess low binding affinities ranging from -6.9 to -7.1 kcal/mol.

Gelstriamine A, a Triamino Monoterpene Indole Alkaloid with a Caged 6/5/7/6/6/5 Scaffold and Analgesic Alkaloids from Gelsemium elegans Stems.

A novel triamino monoterpene indole alkaloid with an unprecedented skeleton, gelstriamine A (1), four new monoterpene indole alkaloids (2-5), and 12 known analogues (6-17) were isolated from Gelsemium elegans. The structures of 1-5 were established using extensive spectroscopic techniques, NMR calculations with iJ/dJ-DP4 and 2D C-H COSY ANNs analysis, ECD calculations, chemical methods, and single crystal X-ray diffraction analysis. Gelstriamine A (1) possesses an unprecedented 6/5/7/6/6/5 heterohexacyclic scaffold bearing a unique hexahydrooxazolo[4,5-b]pyridin-2(3H)-one motif, and a plausible biosynthetic pathway was proposed. All the isolated alkaloids 1-17 showed discernible analgesic activities in an acetic acid-induced writhing test in mice, and N-desmethoxyhumantenine N4-oxide (3) exhibited more potent analgesic activities than those of morphine at doses of 0.04 and 0.2 mg/kg.

Monoterpene-flavonoid conjugates from Sarcandra glabra and their autophagy modulating activities.

Fourteen new monoterpene-flavonoid conjugates including four monoterpene-conjugated chalcones (glabratins A-D, 1-4), seven monoterpene-conjugated dihydrochalcones (glabratins E-K, 5-11), and three monoterpene-conjugated flavanones (glabratins L-N, 12-14), together with four known analogues (15-18) were isolated from the aerial parts of Sarcandra glabra. The structures and the absolute configurations of these compounds were elucidated by the spectroscopic data, single-crystal X-ray diffraction, and electronic circular dichroism (ECD) calculations. Compounds 1, 4-6, 9-14, and 18 showed obvious cell autophagy-inducing activities at 25 µM in HEK293 cells. Furthermore, the bioassay results also showed that 18 induced cell autophagy in a dose dependent manner. Our findings revealed a rare class of monoterpene-flavonoid conjugates in nature and firstly reported their autophagy-inducing activities.

Mosquitocidal effect of monoterpene ester and its acetyl derivative from Blumea mollis (D. Don) Merr against Culex quinquefasciatus (Diptera: Culicidae) and their insilico studies.

The present study was conducted to assess the mosquitocidal efficiency of compound isolated from Blumea mollis (D. Don) Merr against Culex quinquefasciatus. Eggs and larvae of Cx. uinquefasciatus were exposed to different concentrations 0.5, 1.0, 1.5 and 2.0 ppm of compounds prepared using DMSO. Compound 1 was identified as (4R, 5S)-4-hydroxy-7-tigloyloxy carvotanacetone, from which new derivative was synthesized and confirmed as (4R, 5S)-4-acetoxy-7-tigloyloxy carvotanacetone. Both the compounds presented larvicidal and ovicidal activities. Compounds 1 and 2 at 2-ppm concentration showed 64% and 78% larval mortality in 24 h, respectively. The LC50and LC90values of compounds 1 and 2 on Cx. quinquefasciatus larvae were 1.73, 1.27 and 4.59, 3.33 ppm, respectively. The eluted compound 1 and synthesized compound 2 presented 68% and 77% of ovicidal activity, respectively, against eggs of Cx. quinquefasciatus at 120 h post-treatment. Histopathological studies of the compound-treated larvae revealed serious damage on the larval midgut cells. Furthermore, compounds 1 and 2 was tested for toxicity study and the results showed both the compounds were found to be harmless to non-target organism Poecilia reticulata. Computational analysis of compound 2 showed strong binding interaction with the AChE1 of Cx. quinquefasciatus. These results clearly suggest that compounds from Blumea mollis could act as good mosquitocidal agents against Cx.quinquefasciatus and compound 2 was first time reported.

Melognine, a novel monoterpenoid indole alkaloid from Melodinus fusiformis that induce apoptosis in BT549 cells.

A novel monoterpenoid indole alkaloid, melognine (1) possessing an unprecedented skeleton with a 6/6/5/5/6/6 hexatomic rearranged ring system was isolated from the stems of Melodinus fusiformis. The structure with absolute configuration of 1 was established by extensive spectroscopic analyses and quantum ECD calculations. Melognine showed significant cytotoxicity on human breast cancer BT549 cells with an IC50 value of 1.49 µM by MTT assay. Further mechanism of action study indicated that melognine demonstrated the ability to induce apoptosis by activation of caspase-3 and p53, and downregulation of Bcl-2 in BT549 cells.

A new monoterpene-lactone with neuroprotective activity from corn silk.

A new monoterpene-lactone (1) along with five known compounds (2-6) were isolated from corn silk. The structure of the new compound was elucidated based on comprehensive spectroscopic analyses and quantum chemical calculations of electronic circular dichroism (ECD) curves. All compounds were evaluated for their neuroprotective effects against H2O2-induced damage in human dopaminergic neuroblastoma cells (SH-SY5Y). As a result, compound 1 exhibited weak neuroprotective activity.

Chemical Investigation Of Secondary Metabolites Produced By Mangrove Endophytic Fungus Phyllosticta Capitalensis.

Chemical investigation of endophytic fungus Phyllosticta capitalensis, isolated from the hypocotyls of the Chinese mangrove Bruguiera sexangula led to the isolation of eight known secondary metabolites, including four meroterpenes guignardone A (1), 12-hydroxylated guignardone A (2), guignardone J (3), guignardone M (4), and four polyketides xenofuranone B (5), 6,8-dihydroxy-5-methoxy-3-methyl-1H-isochromen-1-one (6), regiolone (7), 3,4-dihydroxybenzoic acid (8). Their structures were elucidated unambiguously based on the comprehensive spectroscopic analysis and comparison with literature data. This is the first report of these compounds being isolated from this fungal species. All compounds isolated were subjected to antimicrobial and cytotoxic activities evaluation.

A Review of Research Progress on Agathis dammara and its Application Prospects for Cardiovascular Diseases and Fatty Liver Disease.

Cardiovascular diseases and fatty liver disease have become the leading causes of death in modern society. However, the currently existing drugs do not solve all issues related to these diseases; thus, it is expected that more potential drugs for clinical use will be developed. Undeniably, natural products have attracted increasing attention. It is of great significance to identify effective active monomer components for drug discovery and disease prevention. As a pure natural product, Agathis dammara (AD) has antioxidant, hypolipidemic, hypoglycemic, antitumor, and anti-inflammatory activities. However, at present, there are few reports regarding the effects of AD on chronic inflammatory cardiovascular diseases, such as aneurysm, atherosclerosis, myocardial ischemia-reperfusion injury, and cardiac hypertrophy and liver diseases such as fatty liver disease. AD and products derived from it have a very broad application prospect for cardiovascular diseases and fatty liver disease.