Records of Natural Products Articles

Genus Lactuca L. belongs to one of the major families of flowering plants, Asteraceae. It includes about 150 species, distributed in warm and temperate areas, commonly in the Northern Hemisphere. Since ancient times, numerous Lactuca L. species have been cultivated for their economic and medicinal significance. Cultivated lettuce (Lactuca sativa), a representative member of the genus, is the most important leafy salad vegetable. The current review aims to provide comprehensive information on the taxonomy, phytochemistry, traditional uses, and biological activities of plants of the genus Lactuca.

One new monoterpene alkaloid (1) and eight known compounds (2–9), belonging to two monoterpene alkaloids (1–2), one pyridine alkaloid (3), four phenylpropanoid derivatives (4–7), and two matrine-type alkaloids (8–9), were isolated from Rauvolfia vomitoria Afzel. The structure of new compound 1 was determined by extensive spectroscopic analysis and electronic circular dichroism (ECD) calculation. Notably, this is the first reported monoterpene alkaloids from R. vomitoria. Besides, compounds 3, 5, and 7–9 were first discovered in the Apocynaceae family and compounds 4 and 6 were first reported in the Rauvolfia genus. This is also the first example of matrine-type alkaloids reported in the Apocynaceae family, indicating that matrine-type alkaloids are not unique to the Leguminosae/Fabaceae family. All isolated compounds were evaluated for their anti-acetylcholinesterase, anti-α-glucosidase, and antioxidant activities. Compound 6 showed significant α-glucosidase inhibitory activity and remarkable DPPH radical scavenging capacity, both of which are superior to the positive controls. Molecular docking of compound 6 with α-glucosidase was further performed, suggesting that compound 6 could form hydrogen bonds with residues ALA-292, ASN-259, and ARG-263.

 Globally, depression is the fourth most common disorder. It is difficult to treat and prone to recurrent episodes. To elucidate the antidepressant effect and mechanism of action of Magnolia sieboldii aromatherapy, the main components of M. sieboldii essential oils were analyzed using GC-MS. A mouse model of depression, established by repeated intraperitoneal injection of reserpine, was used to probe antidepressant efficacy. Behavioral tests were used to evaluate depressive behavior in mice. In in vivo animal studies, changes in the number of measured neurons were detected using Nissl staining, and GR protein expression was examined using immunohistochemistry. The relative expression levels of 5-hydroxytryptamine (5-HT1A) and brain-derived neurotrophic factor (BDNF) were detected using western blot (WB). The results showed that the essential oils of M. sieboldii are mainly composed of β-elemene (22.11%), trans-β-ocimene (14.87%), germacrene D (7.27%), and nerolidol (4.51%). The expression of GR protein was substantially upregulated in the tissues of mice treated with the essential oils of M. sieboldii. WB showed that the components of M. sieboldii essential oils modulated the expression of BDNF and 5-HT in serum, which remarkably attenuated depressive behavior in mice. In addition, a medium concentration of M. sieboldii substantially ameliorated depressive-like behavior in mice and increased the serum levels of 5-HT1A and BDNF. This study suggests that a medium concentration of M. sieboldii has a prominent antidepressant effect.

A pair of unique diastereoisomers of norlignan glycosides named cephalotanols A (1) and B (2), together with two known compounds, have been isolated from the twigs and leaves of Cephalotaxus fortunei Hook. Their structures were elucidated by using a combination of spectroscopic techniques and comparison of experimental and calculated electronic circular dichroism (ECD) data. To our knowledge, cephalotanols A and B represent the first rearranged norlignan glycosides with diphenylvinylcyclopropane core found in natural sources, of which biosynthetic pathways originating from co-occurring precursors 3S-4'-O-β-D-glucopyranosylhinokiresinol (3) and 3S-4''-O-β-D-glucopyranosylhinokiresinol (4) via di-π-methane rearrangement is proposed.

Two new sesquiterpenes (1R,5R,6R)-11-hydroxyl-drocostuslactone (1) and (1R,10S)- gibberodione A (2) were acquired from the leaves of Dalbergia odorifera. The structures of two new sesquiterpenes were revealed by broad NMR exploration, and X-ray crystallography analyses. In addition, the bioactivity assay showed that two compounds had potential anti-inflammatory activity with less toxicity (their IC50 values were 107.2 ± 4.02 and 54.64 ± 1.89 μg/mL), could significantly decrease the production of NO (P<0.01) with 8~16 and 1~2 μg/mL and inhibited LDH (P<0.01) with 1~16 and 1~2 μg/mL in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages, respectively.

A new tigliane-type diterpenoid (1) and three known analogues (2-4) were isolated from the seeds of Croton tiglium. Extensive spectroscopic analyses, especially the 2D NMR experiments were used to determine their structures. The absolute configuration of 1 was defined by single-crystal X-ray diffraction data. The cytotoxicity 1-4 was evaluated against melanoma cell line A375, and the results showed that compounds 1, 3, and 4 exhibited certain cytotoxicities.

Amongst all cancer types, liver cancer is the fourth leading cause of cancer mortality. It is frequently stated as hepatocellular carcinoma (HCC) and occurs in hepatocytes. Genetic alterations of hepatocytes such as Wnt/β-catenin and JAK / STAT signaling pathways play a key role for the development of the HCC. Currently, there are a few available treatments for HCC; such treatments include transplantation, surgical resections and anticancer drugs. Most of the anti-cancer drugs target the signaling pathways for achieving an effective treatment. However, these treatments have some undesirable side effects. Thus, there is a need for discovering alternative anti-cancer agents with no or lesser side effects. Plant constituents are promising anti-cancer agents. Cynara cornigera L. contains plenty of phenolic compounds including quercetin, apigenin, etc. This study aimed to analyze the anti-cancer property of the fractionated methanol extract of the flowers of C. cornigera. All the fractions obtained were analyzed to determine the cytotoxic activity on HepG2 cells. Two of the fractions containing polyphenolic compounds had a significant cytotoxic activity related to non-canonical Wnt11 signaling pathways on HepG2 cells.

A new lignan eplignan A (1), along with six konwn lignans (2–7) was isolated from the herbaceous stems of Ephedra intermedia Schrenket C. A. Meyer. Their structures were elucidated based on the spectroscopic evidence, mainly including NMR and HRESIMS data. The absolute configuration of 1 was determined by comparing calculated and experimental electronic circular dichroic (ECD) spectra. Moreover, all compounds (1–7) were evaluated for their protective effects against the BEAS-2B cells injury induced by TGF-β1 in vitro, and the results showed that compounds 1, 2, 4, and 6 exhibited significantly protective activities at the concentration of 10 μM.

The samples of Clinopodium nepeta (L.) Kuntze (Lamiacae) aerial parts were collected from four different localities in sub-Mediterranean area of Bosnia and Herzegovina and subjected to phytochemical profiling. Shade-dried and fresh samples were used to determine their headspace volatile organic composition by solid-phase microextraction on two differently coated fibers. Corresponding essential oils were obtained by hydrodistillation. Both headspace and essential oil were analysed by gas chromatography-mass spectrometry Among detected compounds, trans-piperitenone oxide and pulegone were dominant in the headspace of shade-dried and fresh C. nepeta samples. The essential oils contained 42 compounds including pulegone (44.8%), piperitenone (48.8%) and trans-piperitenone oxide (60.2%) as the major compounds, followed by limonene, cis-piperitone oxide, p-menthone and dihydrocarvyl acetate. In this work, a wide range of volatile compounds present in C. nepeta samples from Bosnia and Herzegovina was determined. The obtained data provides detail phytochemical analysis of the volatiles of C. nepeta and therefore completes earlier researches of this plant from the other geographical areas. 

Keywords: Clinopodium nepeta (L.) Kuntze; Lamiaceae; headspace solid-phase microextraction; hydrodistillation; essential oil. 

Phytochemical investigation of Lindera myrrha roots growing in Vietnam afforded a new eudesmane sesquiterpenoid, myrrhalindenane C (1), along with seven known compounds, rel-5-(3S,8S-dihydroxy-1R,5S-dimethyl-7-oxa-6-oxobicyclo[3,2,1]-oct-8-yl)-3-methyl-2Z,4E-pentadienoic acid (2), 1-O-(4-hydroxy-2,6-dimethoxyphenoxy)-6-O-[rel-5-(3S,8S-dihydroxy-1R,5S-dimethyl-7-oxa-6-oxobicyclo[3,2,1]-oct-8-yl)-3-methyl-2Z,4E-pentadienoyl]-β-D-glucopyranose (3), curcumin (4), demethoxycurcumin (5), bisdemethoxycurcumin (6), (1E,6E)-1,7-bis(4-methoxyphenyl)-1,6-heptadiene-3,5-dione (7), and 2',4',4,2''-tetrahydroxy-3'-[3''-methylbut-3''-enyl]chalcone (8). The structure was determined by analysis of their MS and NMR data as well as by comparison with literature values. All compounds were evaluated for antimicrobial activity against antibiotic-resistant, pathogenic bacteria Enterococcus faecium, Staphylococcus aureus, and Acinetobacter baumannii.

 Two new spirostanol glycosides, thibetanosides J and K (1 and 2), along with three known ones (3-5) were isolated from the roots and rhizomes of Helleborus thibetanus. Their structures were elucidated by extensive use of spectroscopic techniques and chemical evidence. In this study, compounds 1-5 were evaluated for their cytotoxic activity against HCT116, A549 and HepG2 tumor cell lines. Among them, compound 1 exhibited moderate cytotoxicity against A549 cells (IC50 7.69 ± 1.13 μM) and HepG 2 cells (IC50 8.32 ± 2.63 μM). Compound 2 exhibited moderate cytotoxicity against HCT116 cells (IC50 20.67 ± 1.06 μM).

Two previously unreported compounds (1 and 2) together with eight known compounds (3-10) were isolated from the methanol extract of sea snail Tectus maximus Koch, 1844. Their chemical structures were determined to be 6-acetoxy-deoxyinosine (1), 6-acetoxy-inosine (2), deoxyinosine (3), inosine (4), adenosine (5), deoxyadenosine (6), deoxyuridine (7), thymidine (8), glycerol arachidonate (9), and arachidonic  acid (10) on the basis of HR-ESI-MS and NMR spectroscopic analyses. This is the first report of those compounds from the genus Tectus

A new monoterpene rhamnoside, (+)-(R)-α-terpineol α-L-rhamnoside (1), along with ten known compounds (2–11) were obtained after purification of the ethanol extract of Cercis glabra legumes. Their structures were elucidated by spectroscopic evidence including NMR, optical rotatory dispersion (ORD), HR-ESI-MS and chemical hydrolysis. In the acetylcholinesterase inhibitory assay, compounds 3 and 8 showed high percentages of inhibition which were comparable to the activity of donepezil (a commercial drug, the positive control), and exhibited IC50 values of 0.488, 0.391 mg/mL. These bioactive components could be promising acetylcholinesterase inhibitors.

Two new compounds, carneusins A-B (1-2), as well as fifteen known compounds (3-17), were isolated from the marine-derived fungus Aspergillus carneus GXIMD00519. Their structures were elucidated by the analysis of detailed spectroscopic data and quantum chemistry calculations. All the compounds were evaluated for their antibacterial, antibiofilm and cytotoxic effects. Compound 1 showed a moderate inhibitory effect against MRSA with the MIC value of 32 µg/mL. Compound 2 exhibited an anti-microfouling effect against biofouling bacterial Vibrio rotiferianus and Alteromonas macleodii with MIC value of 64 µg/mL. Compound 5 displayed antibiofilm activity against A. macleodii with the EC50 value of 10.42 ± 0.58 µg/mL. Compounds 1, 3, 4, 8 and 15 showed cytotoxicity against human pancreatic cancer cell lines SW1990, colorectal adenocarcinoma cell line DLD1, human pancreatic cancer cell line PANC1, and human hepatocellular carcinoma cell line Bel7402 with IC50 values ranging of 2.75-17.77 µM.

Abstract: The fungal strain Aspergillus fumigatus CBC18132, isolated from deep-sea sediment, was investigated for secondary metabolites. Fermentation on rice medium followed by chromatographic separation led to the isolation of three polyketides (13) and nine alkaloids (413). The structures were determined by analyses of spectroscopic data (1H and 13C NMR, and MS data). The absolute configuration of the anthraquinone-derivative trypacidin was resolved for the first time by a combination of ECD and specific rotation calculation. All isolated compounds were inactive toward the -glucosidase at the initial concentration of 2 mM.

A new isoflavipucine derivative, (8S, 9R)-dihydroisoflavipucine (1), is isolated from an ethyl acetate extract of endophytic fungi Botryosphaeria dothidea (D4-2) derived from Taxus mairei. The structure of 1 is elucidated based on nuclear magnetic resonance, circular dichroism, and mass spectrometry. The antiproliferative activity of the isolates against breast cancer cells MDA-MB-231, MCF7 and 4T1 are evaluated.

A new carotane sesquiterpene, trichocarotin N (1), was isolated from the culture of marine-derived fungus Trichoderma virens QD-11. Its structure was established by detailed analysis of 1D/2D NMR and HRESIMS data. Trichocarotin N (1) exhibited moderate cytotoxicity against HeLa and MCF-7 cancer cell lines, with IC50 values of 32.4 and 41.6 μM, respectively.

The marine-derived fungus SCZ-1 was cultured on a rice solid medium. The fermented materials was extracted using ethyl acetate to afford an extract, which was separated by repeated column chromatography to afford three polyketides and five alkaloids, including 2 new polyketides (1 and 2). The known compounds were identified to be penipyrol A (3), cyclopenin (4), cyclopenol (5), terretrione D (6), viridicatol (7), and viridicatin (8). The structures of 1 and 2 were determined by extensive analyses of spectroscopic data (1D and 2D NMR, and HRESIMS). The absolute configuration of 2 was assigned by comparing the experimental and calculated ECD spectra. Compound 1, bearing a two-carbon side chain at C-2, is seldom found among isocoumarins. The metabolites were screened for their inhibitions toward a-glucosidase, only compound 8 showed weak inhibitory effect with an IC50 value of 548 mM.

A phytochemical study of the rhizomes of Monstera deliciosa has led to isolation of fourteen compounds (1-14) for the first time from the plant species. The structure elucidation was carried out using 1D and 2D NMR data. The cytotoxic activities of the compounds against the liver (HepG-2), larynx (Hep-2), colon (HCT-116), and breast (MCF-7) cancer cell lines were evaluated using MTT assays. Syringaresinol (6) showed remarkable IC50 values against the four tested cell lines. In addition, 9, 12, 13-trihydroxy-10-octadecenoic acid (14) was highly cytotoxic against Hep-2 and HCT-116 cell lines.

 A novel β-carboline, namely Plagranline A (1), and a known alkaloid (2) were isolated from the roots of Platycodon grandiflorus. Their structure was elucidated using a combination of spectroscopic analyses and computational chemistry, including electronic circular dichroism (ECD) and optical rotatory dispersion (ORD). Alkaloids 1 and 2 exhibited moderate inhibitory effects against NO production. Interestingly, 1 and 2 are the first alkaloid constituents reported from the plant P. grandifloras.

A new sesquiterpene, named todasinoid A (1), together with eight known compounds (2-9) were isolated from the roots of Toddalia asiatica. The gross structure of todasinoid A were established by analyses of the NMR and HRESIMS data. A comparison of the experimental ECD spectrum of 1 with the calculated ECD spectra for a model compound (1a) resolved the absolute configuration of 1. The known compounds were identified to be bullatantriol (2), aculeatin (3), 6-(3-ethoxy-2-hydroxy-3-methylbutyl)-5,7-dimethoxy-2H-1-benzopyran-2-one (4), trans-N-p-coumaroyltyramine (5), feruloyltyramine (6), b-sitosterol (7), sitosterol D-glucoside(8), 7α-hydroxysitosterol (9) by comparing the NMR data and specific rotations with reported data in literature. Compound 1 is an eremophilane-type sesquiterpenoid containing a mercaptolactate side-chain that is rarely found in nature. Compounds 2, 5, and 9 were isolated from this plant for the first time. Bioassay study revealed that compound 5 exhibited inhibitory effects against a-glucosidase with an IC50 of 320 mM, being more active than the positive control acarbose.