Terpenoids from Stinking toe (Hymneae courbaril) fruits with cyclooxygenase and lipid peroxidation inhibitory activities

Stinking toe (Hymenaea courbaril), also called Jatoba and Kerosene tree, is a medicinal plant commonly found in the central and South American countries. In the Caribbean, Mexico and Brazil, the powdery sweet dust of its fruit is consumed for energy. The chemical examination of the yellowish sweet powder of the fruit yielded sucrose and linolenic acid as major compounds. The pods yielded the labdane diterpenoids crotomachlin (1), labd-13E-en-8-ol-15-oic acid (2), labdanolic acid (4), (13E)-labda 7, 13 dien-15-oic acid (5) and labd-8 (17), 13E- dien-15-oic acid (6), along with the sesquiterpene, spathulenol (7), as confirmed by ¹H and ¹³C NMR spectral studies. The methyl ester of labd-13E-en-8-ol-15-oic acid (3) was also characterized during the purification of compound 5. The total amount of these terpenoids in the fruit was about 0.1% (w/w) of the dried fruit. Compounds 1–5 and 7 were assayed for anti-inflammatory activity using cyclooxygenase-1 (COX-1) and -2 (COX-2) enzymes. At 100 ppm, compounds 3 and 4 showed selective COX-2 enzyme inhibition. Also, compounds 1, 2 and 5 inhibited lipid peroxidation by 46%, 48% and 75%, respectively, at 100 ppm. These compounds were isolated from this fruit and their COX and lipid peroxidation inhibitory activities are reported for the first time in this paper.     

A new phragmalin-type limonoid and anti-inflammatory constituents from the fruits of Swietenia macrophylla

The fruit of Swietenia macrophylla is commercially used in healthcare products for the improvement of blood circulation and skin condition. A new phragmalin-type limonoid, 6-O-acetyl-3′-demethylswietephragmin E (1), has been isolated from the fruit of S. macrophylla, together with 16 known compounds. The structure of this new compound was determined through spectroscopic and MS analyses. 6-O-Acetyl-3′-demethylswietephragmin E (1), 3,6-O,O-diacetylswietenolide (5), 3-O-tigloylswietenolide (6), 3-O-tigloyl-6-O-acetylswietenolide (8), swietemahonin E (9), and 6-O-acetylswietemahonin G (10) exhibited inhibition (IC₅₀ ? 35.7 μM) of superoxide anion generation by human neutrophils in response to formyl-l-methionyl-l-leucyl-l-phenylalanine (fMLP).     

New flavonol glycosides from Barbeya oleoides Schweinfurth

Three new flavonol glycosides, 3′,5′ dimethoxymyricetin-4″-O-α-l-rhamnopyranosyl (1–4) β-d-glucopyranoside (1), 3′-methoxyquercetin-4″-O-α-l-rhamnopyranosyl (1–4) β-d-glucopyranoside (2) and 3′-methoxyqurecetin-6″-O-α-l-rhamnopyranosyl (1–6) β-d-glucopyranoside (3), have been isolated from the aerial part of Barbeya oleoides Schweinf., along with twelve known compounds, uvaol (4), ursolic acid (5), corosolic acid (6), arjunolic acid (7), β-sitosterol-3-O-β-d-glucoside (8), (+)–catechin (9), (-)-epicatechin (10), isorhamnetin-4′-O-glucoside (11), arjunglucoside I (12), d-(-)-bornesitol (13), gallocatechin (14) and epigallocatechin (15). Compounds 4–15 were isolated for the first time from Barbeyaceae. Structure elucidation of compounds 1–3 was based on MS and NMR data. The ethyl acetate extract of the stems as well as compounds 5, 6, 14 and 15 showed significant antimicrobial activity, while the ethanol extracts of leaves, stems and compounds 4, 7, 8, 13–15 have dose-dependent spasmolytic action.     

Quinic acid esters and sesquiterpenes from Sonchus arvensis

A phytochemical study on the whole plant of Sonchus arvensis and its antioxidant activity has been carried out. Three quinic acid derivatives (1–3), the rarely naturally occurring (p-hydroxyphenylacetyl) quinic acids, and two eudesmanolides (4 and 5) were newly found. Four known eudesmanolides (6–9) were isolated from the plant for the first time. Their structures were characterized by HRESIMS, IR, UV, 1D NMR, and 2D NMR. 1,1-Diphenyl-2-picrylhydrazyl (DPPH·)-scavenging activity was evaluated for each of the above 9 compounds (1–9) in comparison to standard antioxidants (caffeic acid and ascorbic acid). However, none proved to have a positive activity. The absence of antioxidant activity could be caused by the absence of ortho or para-diphenolic groups in all detected compounds, that are responsible of the activity against free radicals by an electron transfer reaction.     

TLC bioautography-guided isolation of antioxidants from fruit of Perilla frutescens var. acuta

Guided isolation through bioautography on TLC using 1,1-diphenyl-2-picryl-hydrazyl radical (DPPH) as a detection reagent led to the isolation of four antioxidant compounds from fruit of Perilla frutescens var. acuta. These compounds were identified as rosmarinic acid (1), luteolin (2), apigenin (3), and chrysoeriol (4), by means of UV, NMR, and ESI MS. All the compounds were isolated for the first time from the fruit of the plant. Compounds 1 and 2 showed significant DPPH scavenging capacities, with IC₅₀ values of 8.61 and 7.50 μM, respectively. Further quantitative HPLC analysis confirmed that compounds 1-4 are the predominant contributors to the free radical scavenging activity of the extract of P. frutescens var. acuta.     

Antioxidant activity of a new phenolic glycoside from Lagenaria siceraria Stand. fruits

The antioxidant properties of different extracts of Lagenaria siceraria (bottle gourd) fruit were evaluated. In the process, a new phenolic glycoside (E)-4-hydroxymethyl-phenyl-6-O-caffeoyl-β-d-glucopyranoside (1) was isolated and identified together with 1-(2-hydroxy-4-hydroxymethyl)-phenyl-6-O-caffeoyl-β-d-gluco-pyranoside (2), protocatechuic acid (3), gallic acid (4), caffeic acid (5) and 3,4-dimethoxy cinnamic acid (6). Their structures were elucidated by extensive NMR experiments including ¹H-¹H (COSY) and ¹H-¹³C (HMQC and HMBC) spectroscopy and chemical evidences. The antioxidant potential of the compound 1 and 2 was tested in different in vitro assay systems such as free radical scavenging assay, 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay, superoxide scavenging activity, reducing power assay and linoleic acid peroxidation assay.     

Isolation and structural characterisation of five new and 14 known metabolites from the commercial starfish Archaster typicus

From the commercially available starfish Archaster typicus, five new (1–5) and 14 known (6–19) metabolites were isolated and identified. Detailed 1D and 2D NMR spectroscopic data, including ¹H, ¹³C, DEPT, HSQC, HMBC, and NOESY, established the structures of the new metabolites as sodium 5α-cholesta-9(11),24-dien-3β,6α,20β-triol-23-one 3-sulphate (1), sodium 5α-cholesta-9(11)-en-3β,6α,20β-triol-23-one 3-sulphate (2), sodium (25R)-5α-cholestane-3β,4β,6α,8,14α,15β,26-heptaol-15-sulphate (3), sodium (25R)-5α-cholestane-3β,6α,8,14α,15β,26-hexaol 15-sulphate (4), and sodium cholest-25(27)-ene-3β,4β,5α,6α,7β,8β,14α,15α,24,26-decanol 6-sulphate (5). Other spectroscopic techniques, including IR, ESI–MS, and HR-ESI–MS, were also adopted to further confirm the structures of the metabolites. These five steroids (1–5) are reported in nature for the first time. All of the steroids found in A. typicus (1–12) were tested for anticancer activities against MDA-MB-435 and Colo205 tumour cells. However, only sodium 5α-cholesta-9(11)-en-3β,6α,20β-triol-23-one 3-sulphate (2) and 27-nor-5α-cholestane-3β,4β,5,6α,7β,8,14,15α,24α-nonaol (6) exhibited weak activities.     

Jasmonoid glucosides,sesquiterpenes and coumarins from the fruit of Clausena lansium

The fruit of Clausena lansium (wampee) is popular in southern China and warm areas of the world. Our chemical study on the fruit yielded three jasmonoid glucosides, 12-β-d-glucopyranosyloxy-6-epi-7-isocucurbic acid-1,6-lactone (1), 12-β-d-glucopyranosyloxyjasmonic acid (2) and 12-hydroxyjasmonic acid (3), two sesquiterpenes, (+)-curcumen-12-oic acid (4) and (+)-(E)-α-santalen-12-oic acid (5), two coumarins, xanthotoxol (6) and indicolactone (7), in addition to 3,4-dihydroxybenzoic acid (8), 5-hydroxymethylfuraldehyde (9), isopropyl β-d-glucopyranoside (10) and stigmasterol (11). Their structures were determined by spectroscopic methods. Compound 1 was a new metabolite and the others excluding 6 were reported from the species for the first time. Compounds 1–7 were evaluated for antioxidant and antibacterial activities. Among them, compound 6 showed antioxidant activity in ferric reducing antioxidant power (FRAP) and DPPH radical scavenging assays as well as antibacterial activity against Staphyloccocus aureus and Shigella dysenteriae, while compound 5 was active against Bacillus cereus.     

Abietane diterpenoids from Isodon lophanthoides var. graciliflorus and their cytotoxicity

Seven new (1–7) and three known (8–10) abietane diterpenoids were isolated from the methanolic extract of the aerial parts of Isodon lophanthoides var. graciliflorus (Lamiaceae), a folk Chinese medicine and an herb for functional beverages. They were identified as 16-acetoxylsugiol (1), graciliflorin E (2), graciliflorin F (3), 15-O-methylgraciliflorin F (4), 15-hydroxy-20-deoxocarnosol (5), 3β-hydroxysempervirol (6), 15-hydroxy-1-oxosalvibretol (7), abieta-8,11,13-triene-14,19-diol (8), 6,12,15-trihydroxy-5,8,11,13-abietatetraen-7-one (9), and 3α-hinokiol (10) based on the spectroscopic data including COSY (correlated spectroscopy), HMBC (heteronuclear multiple bond correlation), and HR-ESI-MS (high-resolution electrospray ionization mass spectrometry). All the compounds except 10 were obtained from I. lophanthoides for the first time. Compounds 1, 2, 5, 6, 8, and 9 exhibited in vitro cytotoxicity against A549 (human lung adenocarcinoma), MCF-7 (human breast adenocarcinoma), and HeLa (human cervical carcinoma) cell lines with the IC₅₀ values of 1.79–52.67 μM.     

Polyphenols from longan seeds and their radical-scavenging activity

Five previously uncharacterised polyphenols, ethyl gallate (2), 1-β-O-galloyl-d-glucopyranose (3), methyl brevifolin carboxylate (4), brevifolin (5) and 4-O-α-l-rhamnopyranosyl-ellagic acid (8), and three previously identified polyphenols, gallic acid (1), corilagin (6) and ellagic acid (7), were isolated from longan seeds. Their structures were identified by spectroscopic and chemical methods including HRESIMS and NMR. Eight polyphenols exhibited scavenging activity towards DPPH radicals with SC₅₀ values of 0.80–5.91 μg/ml and towards superoxide radicals with SC₅₀ values of 1.04–7.03 μg/ml. The radical-scavenging activity of the newly characterised polyphenols was comparable to that of gallic acid, corilagin and ellagic acid.     

Studies on the antioxidant potential of flavones of Allium vineale isolated from its water-soluble fraction

The aim of this work was to examine the chemical constituents and antioxidant potential of water-soluble fractions from the commonly consumed vegetable, Allium vineale. The water-soluble fraction, containing phenolic compounds, was extracted with ethyl acetate to obtain flavonoids which were separated and purified by repeated column chromatography over Sephadex LH-20, RP C18 and silica gel. The isolated compounds were identified according to their physicochemical properties and spectral data (UV, HPLC–TOF/MS, ¹H NMR, ¹³C NMR and 2D NMR). Three flavonoids were isolated and identified as chrysoeriol-7-O-[2″-O-E-feruloyl]-β-d-glucoside (1), chrysoeriol (2), and isorhamnetin-3-β-d-glucoside (3). Antioxidant studies of the aqueous extract and three isolated compounds, 1, 2, 3, were undertaken and they were found to have significant antioxidant activity. Antioxidant activities were evaluated for total antioxidant activity by the ferric thiocyanate method, ferric ion (Fe³⁺) reducing antioxidant power assay (FRAP), ferrous ion (Fe²⁺) metal chelating activity, and DPPH free radical-scavenging activity. The water-soluble ethyl acetate and methanol extraction methods were also compared using HPLC–TOF/MS.     

Effects of Amelanchier fruit isolates on cyclooxygenase enzymes and lipid peroxidation

Bioassay-directed isolation and purification of the ethyl acetate and methanol extracts of Amelanchier canadensis resulted in 1,3-dilinoleoyl 2-olein (1), 1,3-dioleoyl 2-linolein (2), 5-hydroxymethyl-2-furfural (3), 5-(sorbitoloxymethyl)-furan-2-carboxaldehyde (4), 5-(mannitoloxymethyl)-furan-2-carboxaldehyde (5), and 5-(α-d-glucopyranosyloxymethyl) furan-2-carboxaldehyde (6). Four compounds, oleanolic acid (7), ursolic acid (8), kaempferol-3-O-α-l-rhamnopyranosyl (1 ← 2) rhamnopyranoside (9), and kaempferol-3-O-α-l-rhamnopyranoside (10) were isolated from the ethyl acetate extract of fresh fruits of Amelanchier arborea. The compounds were isolated and purified by various chromatographic techniques and characterized by NMR and GC/MS methods. The isolated compounds inhibited lipid peroxidation (by 85%) at 100 ppm when compared to 89%, 87%, and 98% for the commercial antioxidants butylated hydroxy anisole (BHA), butylated hydroxytoluene (BHT), and tert-butylhydroxyquinone (TBHQ) at 1.67, 2.2, and 1.67 ppm, respectively. Although not selective, some of these compounds inhibited cyclooxygenase (COX)-1 and -2 enzymes. Compounds 3–6 were isolated for the first time from A. canadensis and compounds 7–10 were isolated for the first time from A. arborea fruits.     

Studies on cytotoxic triterpene saponins from the leaves of Aralia elata

Aralia elata has long been used as a tonic, anticancer and antidiabetic agent in China and Japan, and is widely consumed as food. Phytochemical investigation of the leaves of A. elata has led to the isolation of four new compounds, 3-O-[β-d-glucopyranosyl(1 → 3)-β-d-glucopyranosyl] echinocystic acid 28-O-β-d-glucopyranosyl ester (congmuyenoside I, 1), 3-O-[β-d-glucopyranosyl(1 → 2)-β-d-glucopyranosyl] hederagenin 28-O-β-d-glucopyranosyl ester (congmuyenoside II, 2), 3-O-{[β-d-glucopyranosyl(1 → 2)]-[β-d-glucopyranosyl(1 → 3)-β-d-glucopyranosyl(1 → 3)]-β-d-glucopyranosyl} echinocystic acid 28-O-β-d-glucopyranosyl ester (congmuyenoside III, 3) and 3-O-β-d-glucopyranosyl caulophyllogenin 28-O-β-d-glucopyranosyl ester (congmuyenoside IV, 4), and eight known triterpene saponins (5–12). The structural determination was accomplished with spectroscopic analysis, in particularly ¹³C NMR, 2D NMR and HR-ESI-MS techniques. In addition, compounds 5–10 were found for the first time in the genus Aralia. Compounds 1–12 were tested for their inhibition of the growth of HL60, A549 and DU145 cancer cells. In addition, compound 8 showed significant cytotoxic activities against HL60, A549 and DU145 cancer cells with IC₅₀ values of 15.62, 11.25 and 7.59 μM, respectively.     

New benzenoids and anti-inflammatory constituents from Zanthoxylum nitidum

Zanthoxylum nitidum is commercially used in healthcare products for the improvement of tooth condition. Its fruit is also used as a spice. Three new benzenoids, (E)-4-(4-hydroxy-3-methylbut-2-enyloxy)benzaldehyde (1), (E)-methyl 3-(4-((E)-4-hydroxy-3-methylbut-2-enyloxy)phenyl)acrylate (2), and (Z)-methyl 3-(4-((E)-4-hydroxy-3-methylbut-2-enyloxy)phenyl)acrylate (3), have been isolated from the stem wood of Z. nitidum, together with 17 known compounds (4–20). The structures of these new compounds were determined through spectroscopic and MS analyses. Compounds 8–10, 13, 14, 17, and 18 exhibited inhibition (IC₅₀ ? 7.95 μg/ml) of superoxide anion generation by human neutrophils in response to formyl-l-methionyl-l-leucyl-l-phenylalanine/cytochalasin B (fMLP/CB). Compounds 7–9, 13, 14, and 17 inhibited fMLP/CB-induced elastase release with IC₅₀ values ?7.45 μg/ml.     

Phenolic compounds isolated from Zingiber officinale roots inhibit cell adhesion

Inhibitors of cell adhesion molecule-mediated cell adhesion might be novel therapeutic agents for the treatment of various inflammatory diseases. In this study, nine phenolic compounds were isolated from the methanol extracts of Zingiber officinale roots by bioactivity-guided fractionation. The structures of the compounds were determined by spectroscopic analysis (¹H, ¹³C NMR and MS), to be 6-gingerol (1), 8-gingerol (2), 10-gingerol (3), 6-shogaol (4), 8-shogaol (5), 10-shogaol (6), dehydro-6-gingerdione (7), dehydro-10-gingerdione (8) and 6-paradol (9). Compounds 3, 4, 5 and 7 inhibited direct binding between sICAM-1 and LFA-1 of the THP-1 cells in a dose-dependent manner with IC₅₀ values of 57.6, 27.1, 65.4 and 62.0 μM, respectively. Compounds 4 and 7 had an inhibitory effect on direct binding between sVCAM-1 and VLA-4 of THP-1 cells. These results suggest that the phenolic compounds from Z. officinale roots are good candidates for therapeutic strategies aimed at inflammation.     

Biguaiascorzolides A and B: Two novel dimeric guaianolides with a rare skeleton,from Scorzonera austriaca

The root of Scorzonera austriaca has been used in indigenous cuisines as a delicious food and in the Tibetan traditional medicine in northwestern China. Two novel dimeric guaianolides linked by a carbon–carbon bond with a rare carbon skeleton, termed biguaiascorzolides A (1) and B (2), respectively, have been isolated from roots of S. austriaca. Acetylation of 1 gave 1a. The structures of 1, 1a and 2 were characterised by HR-ESI-MS, EI-MS, UV, IR, and 1D- and 2D-NMR techniques (¹H and ¹³C NMR, ¹H-¹H COSY, HMQC, HMBC, and NOESY experiments). The cytotoxicity of 1a was assayed against selected cancer cell lines, including the human erythroleukaemia adriamycin-resistant subline (K562/ADM) and human stomach carcinoma (MGC-803) cell lines. Compound 1a exhibits a moderate activity against K562/ADM cell lines (IC₅₀ 39.8 μm) and is inactive towards MGC-803 cell lines.     

Tyrosinase inhibitors from paper mulberry (Broussonetia papyrifera)

Fractionation of a chloroform-soluble extract from twigs of Broussonetia papyrifera, led to the isolation of one new compound, 3,5,7,4′-tetrahydroxy-3′-(2-hydroxy-3-methylbut-3-enyl)flavone (1), and 10 known compounds, uralenol (2), quercetin (3), isolicoflavonol (4), papyriflavonol A (5), broussoflavonol F (6), 5,7,3′,5′-tetrahydroxyflavanone (7), luteolin (8), isoliquiritigenin (9), broussochalcone A (10) and 5,7,3′,4′-tetrahydroxy-3-methoxyflavone (11). Their structures were identified by interpretation of MS, ¹H NMR, ¹³C NMR, HMQC and HMBC data. Their inhibitory activities on mushroom tyrosinase using l-tyrosine as substrate were investigated and the IC₅₀ values of 3,5,7,4′-tetrahydroxy-3′-(2-hydroxy-3-methylbut-3-enyl)flavone, uralenol, quercetin and broussoflavonol F were found to be 96.6, 49.5, 57.8, and 82.3 μM, respectively, better than arbutin, a well-known tyrosinase inhibitor.     

Phenolic constituents from the flower buds of Lonicera japonica and their 5-lipoxygenase inhibitory activities

Thirteen phenolic constituents, luteolin (1), protocatechuic acid (2), caffeic acid (3), flavoyadorinin-B (4), 4,5-dicaffeoylquinic acid (5), luteolin 7-O-β-d-glucopyranoside (7), 3,5-dicaffeoylquinic acid methyl ester (8), methyl chlorogenate (9), quercetin 3-O-β-d-glucopyranoside (10), 3,5-dicaffeoylquinic acid (11), rhoifolin (12), chlorogenic acid (13), and a novel phenolic glucoside benzoate, vanillic acid 4-O-β-d-(6-O-benzoylglucopyranoside) (6), were isolated from the flower buds of Lonicera japonica. Flavoyadorinin-B (4) was isolated for the first time from a Caprifoliaceae plant. The structures of 1–13 were determined on the basis of chemical and spectroscopic evidence. These compounds were screened for their 5-lipoxygenase inhibitory activity. Only luteolin (1) showed significant inhibitory activity against 5-LOX-catalysed leukotriene production.     

Dicaffeoylquinic acid derivatives and flavonoid glucosides from glasswort (Salicornia herbacea L.) and their antioxidative activity

Two novel antioxidant compounds, isoquercitrin 6″-O-methyloxalate (6) and methyl 4-caffeoyl-3-dihydrocaffeoyl quinate (salicornate, 7), were isolated from Salicornia herbacea L.. Six known compounds were also identified as 3,5-dicaffeoylquinic acid (1), quercetin 3-O-β-d-glucopyranoside (2), 3-caffeoyl-4-dihydrocaffeoylquinic acid (3), methyl 3,5-dicaffeoyl quinate (4), 3,4-dicaffeoylquinic acid (5), and isorhamnetin 3-O-β-d-glucopyranoside (8). Their chemical structures were determined by spectroscopic data from ESI–MS and NMR. The isolated dicaffeoylquinic acid derivatives (1, 3, 4, 5, and 7) showed similar activities for scavenging 1,1-diphenyl-2-picrylhydrazyl radicals and inhibiting formation of cholesteryl ester hydroperoxide during copper ion-induced rat blood plasma oxidation. The two flavonol glucosides (2 and 6), which have no substitutions in the B ring of their aglycones, also had similar activity. However, compound 8, which has the same structure as 2 except for the presence of a methoxyl group in the C-3′ position of the B ring, showed predominantly lower antioxidant activity than the other isolated compounds.     

Novel acetylated flavonoid glycosides from the leaves of Allium ursinum

Seven flavonoid glycosides, kaempferol 3-O-α-L-rhamnopyranosyl (1→2)-[3-O-acetyl]-β-D-glucopyranoside (1), kaempferol 3-O-α-L-rhamnopyronosyl (1→2)-[6-O-acetyl]-β-D-glucopyranoside (2), kaempferol 3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (3), kaempferol 3-O-β-D-glucopyranoside (4), kaempferol 3,7-di-O-β-D-glucopyranoside (5), 7-O-β-D-glucopyranosyl kaempferol 3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (6), kaempferol 3-O-α-L-rhamnopyranosyl (1→2)-β-D-glucopyranoside-7-O-[2-O-(trans-p-coumaroyl)]-β-D-glucopyranoside (7) were isolated from the n-butanol fraction of Allium ursinum L. and the structures of these compounds were elucidated on the basis of mass spectrometry, ¹H NMR, ¹³C NMR, HMQC and HMBC data. Among them, 1 and 2 are novel compounds and compounds 4 and 5 were isolated from this plant species for the first time.