Records of Natural Products Articles

 Collection of Sideritis raeseri subsp. raeseri has a long tradition in local communities in the Ohrid-Prespa region. The aim of the present study was the analysis of bioactive compounds especially those with anti-inflammatory activity. Combination of the UV and MS data allowed the characterization of 17 compounds, which could be classified into flavonoid glycosides or hydroxycynnamic acid derivatives. Six of them were isolated using preparative HPLC: isoscutellarein 7-O-[6′″-O-acetyl- β -D-allopyranosyl-(1→2)]- β -D-glucopyranoside, 4′-O-methylhypolaetin 7-O-[6′″-O-acetyl- β -D-allopyranosyl-(1→2)]-β -D-glucopyranoside, hypolaetin 7-O-[6′″-O-acetyl- β -D-allopyranosyl-(1→2)]-6″-O-acetyl- β -D-glucopyranoside, 4′-O-methylisoscutellarein 7-O-[6′″-O-acetyl- β -D-allopyranosyl-(1→2)]- β -D-glucopyranoside, isoscutellarein 7-O-[6′″-O-acetyl- β -D-allopyranosyl-(1→2)]-6″-O-acetyl- β -D-glucopyranoside and 4′-O-methylhypolaetin 7-O-[6′″-O-acetyl- β -D-allopyranosyl-(1→2)]-6″-O-acetyl- β -D-glucopyranoside. The presence of phenylpropanoid glycoside martynoside was reported for the first time in the wild growing S. raeseri subsp. raeseri. Hypolaetin derivatives, known for their antiinflammatory activity, dominated and were more abundant in S. raeseri subsp. raeseri grown in NPG in comparison with S. scardica grown nearby the NPG. The type of solvent affected distribution and the amount of bioactive compounds and the advantage was given to less polar extracts which were richer in hypolaetin derivatives.

Part of this work deals with t he isolation and structure elucidation of the main polar secondary metabolites of the aerial parts of Retama raetam(Forssk.) Webb & Berthel, as well as the evaluation of their potential analgesic properties , while the rest deals with the antioxidant activities of the aqueous extracts of roots, stem, fruits and flowers of the plant . It was found that the isoflavones g enistein 1, 6-hydroxygenistein 2, 3'-O-methylorobol 3, pratensein 4, biochanin A 8, the flavones 6-hydroxyapigenin 7 and luteolin 5, the flavonol kaempferol 6,as well as the phenolic compound p-coumaric acid 9 reduce significantly the pain at a concentration dose of 1 mg/kg. The most active compounds were 3 and 8 (86.19% and 75.23%, respectively). The obtained aqueous extracts of R. raetam were also evaluated for their antioxidant activities using two different photometric methods; the results revealed that all extracts exerted very low free radical scavenging activity compared to the well-known butylated hydroxytoluene (BHT) and lower hydrogen peroxide blocking activity than positive control gallic acid.

The essential oils from the areal parts (flower, leaf and stem) of Astragalus hamzaoglui were isolated by hydrodistillation (HD) and a microwave distillation (MD) process. The composition of the volatiles was analysed by GC-FID and GC-MS and screened for their in vitro antimicrobial activity. Totals of 68/64, 65/64, and 68/67 compounds were identified in the flower, leaf, and stem oils of A. hamzaoglui accounting for 92.9-95.0% in HD and 87.4-90.7% in MD, respectively. The essential oils consisted mainly of oxygenated monoterpenes (flower, HD: 33.3% vs. MD: 2.3%, leaf, HD: 8.0% vs. MD: 2.7%, stem, HD: 10.8% vs. MD: 4.7%), alcohols (flower, HD: 13.6% vs. MD: 10.4%, leaf, HD: 51.6% vs. MD: 3.6%, stem, HD: 35.4% vs. MD: 7.6%) and aldehydes (flower, HD: 15.5% vs. MD: 27.9%, leaf, HD: 10.0% vs. MD: 14.8%, stem, HD: 17.2% vs. MD: 24.5%). The major component of the oils of A. hamzaogluiw as 1-octene-3-ol (flower, HD: 11.3% vs. MD: 8.8%, leaf, HD: 45.50% vs. MD: 3.3%, stem, HD: 32.6% vs. MD: 6.9%). Oxygenated sesquiterpenes were the minor constituents in all parts (flower, HD: 0.8% vs. MD: 0.4%, leaf, HD: 0.2% vs. MD: 0.4%, stem, HD: 0.4% vs. MD: 0.4%). of the A. hamzaoglui. Comparative study showed that the amount of total volatiles (flower, 95.0%, leaf, 92.9%, and stem, 95.0%) and the major constituent for the low molecular weight of essential oils were found to be better in HD of A. hamzaoglui. The oils were screened for antimicrobial activity against 12 microorganisms and showed antibacterial and antifungal activities against Escherichia coli, Staphylococcus aureus, Bacillus cereus 702 Roma, Mycobacterium smegmatis, and Saccharomyces cerevisiae. The antifungal activity was observed for the all tested oils against S. cerevisiae except stem oil of HD.

The antioxidant and cytoprotective activities of the hydroalcoholic extract of Chiliadenus montanus, widely used in Egyptian traditional medicine, were investigated. The antioxidant potential, determined using ORAC assay, revealed that Chiliadenus montanus extracts are active radical scavengers (ORAC value 1.720 µmol TE/mg sample). Total phenolic content, measured by Folin-Ciocalteau, was 107.4 mg galic acid/g sample. HPLC and HPLC-MS analysis allowed individual polyphenolic compounds to be identified. Furthermore, the cytoprotective effect of Chiliadenus montanus hydroalcoholic extracts was analyzed in an in vitro oxidative stress model employing H 2O 2 as an oxidant inductor and the human astrocytoma U373-MG cell line as cell model. The results obtained showed that Chiliadenus montanus hydroalcoholic extracts exert a protective action by decreasing cell death and by inhibiting intracellular ROS production, suggesting that these polyphenol-enriched extracts may be useful for those oxidative stress-related neurodegenerative diseases.

The essential oils of the leaves of Phoebe angustifolia Meisn, Machilus velutina Champ. ex Benth and Neolitsea polycarpa H. Liu., were analyzed by gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC-MS). The major compound found in the oils of Phoebe angustifolia were n -hexacadecanoic acid (13.0%), spathulenol (17.0%), sabinene (6.0%), artemisia triene (5.1%) and bicyclogermacrene (5.9%). Appreciable quantities of ( E )-β-ocimene (9.5%), ( Z )-β-ocimene (8.2%), germacrene D (6.8%), allo-ocimene (6.4%), α-phellandrene (5.9%), β-caryophyllene and bicyclogermacrene (ca 5.5%) could be identified from Machilus velutina . However, we have identified ( E )-β-ocimene (85.6%) as the singly abundant constituent of Neolitsea polycarpa with significant amounts of limonene (6.5%). Apart from allo-ocimene (1.8%) and spathulenol (1.1%), the other nineteen compounds were identified in amount less than 1%. This is the first comprehensive report on the volatile oils of the studied species.

 Residues obtained after isolating essential oil very often constitute more than 99% of the total raw material. Such residues are poorly exploited although they may represent a potential sustainable source for valuable natural products. This study investigated antioxidant properties and the composition of bioactive compounds (total phenolics, flavonoids, flavonols) present in the deodorized extracts of Tussilago farfara flowers and stems collected in Lithuania and South of France, which were isolated with acetone, methanol or ethanol. Online HPLC/UV/DPPH scavenging assay showed that among 8 identified by HPLC/MS compounds, di caffeoylquinic acids and quercetin pentoside were the major radical scavengers in the T. farfara extracts .

 The MeOH extract of aerial parts of H. monbretii Spach. have yielded quercetin (1), kaempferol (2), quercitrin (3), hyperin (4), myricitrin (5), rutin (6), I 3 II 8′′ biapigenin (7), methyl chlorogenate (8), 5-O-p-coumaroylquinic acid (9), and chlorogenic acid (5-O-caffeoyl quinic acid) (10), mangiferin (11), and shikimic acid (12). Three compounds 1, 2 and 4 were found to have an immunomodulating inhibitory activity on the oxidative burst response of human neutrophils, as well on mouse peritoneal macrophages. E ffects of compounds on whole blood phagocytes activity was found to be with IC 50 ranging between 8.0-12.2 µg/mL. O nly compounds 1, and 2 were found to interfere with T-cell proliferation, and IL-2 release in PHA activated peripheral blood mononuclear cells system. To the best of our knowledge, this is the first report of phytochemical and biological activity study on H. montbretii Spach.

 A new prenylated xanthone, 1,6-dihydroxy-3,7-dimethoxy-2-(3,7-dimethyloct-2,6-dienyl) xanthone (3-O-methylcowaxanthone) (1), together with four known xanthones, cowaxanthone (2), 7-O-methylgarcinone (3), α-mangostin (4) and γ-mangostin (5) were isolated from the latex of Garcinia cowa. The structure of compound 1 was elucidated on the basis of spectroscopic data interpretation, including 1D and 2D NMR and HREIMS. The cytotoxic activitiy of 1against five human cancer cell lines, HL-60, SMMC-7721, A-549, MCF-7 and SW480, was evaluated, but it was inactive (IC 50>40μM).

Methanol (ME) and hot water extracts (WE) of carob tree sapwood (Ceratonia siliqua L.) exhibited high antioxidant activity and were rich in phenolic compounds, with the main compounds identified by HPLC/DAD as gentisic acid and (-)-epicatechin. The ME displayed a high in vitro antitumor activity against human tumoural cell lines and reduced intracellular ROS production by HeLa cells after treatment with H 2O 2.
(-)-Epicatechin was shown to contribute to the cytotoxic activity of the ME. This is the first report on the biological activity of carob tree sapwood.

 T he sucrose esters 1 and 2 together with the flavonoid rutin (3) were isolated from the calyxes of Physalis solanaceus while 4,7-didehydrophysalin B (4) was obtained from the roots. The structural elucidation of the isolates was carried out by analysis of their spectroscopic data. Compound 4 was obtained as natural product for the first time.

The composition of leaf cuticular neutral lipids of Amphoricarpos autariatus ssp. autariatus collected at canyon of river Tara (North Montenegro) was investigated by GC/MS (nonpolar fraction), LC-ESI TOF MS and 1H NMR spectroscopy (more polar fraction). The nonpolar fraction (ca. 15% of the whole surface extract) contained C 27 - 33 n-alkanes, those with odd-number of carbons predominating. The LC-ESI MS and 1H NMR of the more polar fraction revealed 13 sesquiterpene lactones, constituting ca. 97.5% of the lactone mixture, identified as the known guaianolides, so-called amphoricarpolides, found previously in the aerial parts of the genus. The lactone fraction exhibited considerable in vitro effect against eight fungi, i.e. Aspergillus ochraceus , A. niger, A. versicolor , Penicillium funiculosum, P. ochrochloron, Trichoderma viride, Fusarium verticillioides and Fulvia fulvum.

 A new cyathane diterpene, cyrneine E (1) was isolated from the mushroom Sarcodon cyrneus. The structure of the novel compound was determined by analysis of its spectroscopic data.

 Chlorogenic acid (1), scutellarin (2), syringin (3), 6S, 9R-roseoside (4) and b -sitosterol-3- O - b - D-glucopyranoside (5) were isolated from the aerial parts of Centaurea cadmea Boiss. (Asteraceae). S tructure elucidation of the compounds were performed by using spectroscopic methods (1-D and 2-D NMR and LC-MS-MS). To the best of our knowledge, compounds 1 , 2, 3 and 4 have been isolated for the first time from this endemic species. C ompound 4 is new for the genus Centaurea.

 In the search for novel cytotoxic agents, sesquiterpenoids and phenylpropanoids have provided interesting lead compounds. From the chloroform extract of the underground parts of Laserpitium latifolium , the daucane sesquiterpenoids laserpitin and acetyldesoxodehydrolaserpitin, and the phenylpropanoids laserin and latifolon were isolated as the major compounds. Acetyldesoxodehydrolaserpitin is identified for the first time in the genus Laserpitium. Using a MTT and a sulforhodamine B (SRB) assay, the cytotoxic and antiproliferative activity of the extract and compounds laserpitin, acetyldesoxodehydrolaserpitin and laserin was tested in two closely related human breast adenocarcinoma cell lines, ie. the invasive MCF 7/6 and the non-invasive MCF 7/AZ. The IC 50 values of the extract were in the range of 184.72 – 397.16 μg/mL, with the most potent effect observed in the MTT test on the MCF 7/6 line. Among the tested compounds, acetyldesoxodehydrolaserpitin exerted a most potent, concentration-dependent effect (IC 50 values of 0.60 and 0.51 m M in the MCF 7/6 cell line, and 2.29 m M and 31.87 m M in the MCF 7/AZ cell line in the MTT and SRB test, respectively). The effect of laserin was more pronounced in the MTT test (IC 50 of 4.57 and 2.46 m M in the MCF 7/6 and MCF 7/AZ, respectively).

In order to find new molecules for anti-viral drug design, we screened 102 ethyl acetate extracts obtained from 51 plants native from New-Caledonia for an antiviral activity against the dengue 2 virus RNA dependant RNA polymerase (DENV-NS5 RdRp). Leaf and bark extracts of Myrtopsis corymbosa which strongly inhibited the DENV-NS5 were selected for chemical investigation. We present here the first chemical study of M. corymbosawhich led us to isolate three coumarins, namely ramosin (1), myrsellinol (1) and myrsellin (3), and three alkaloids, namely skimmianine (4), γ-fagarin (4) and haplopin (6). These compounds were identified as major compounds from the active extracts of the plant. However, they demonstrated only weak antiviral activity on the dengue virus. Further studies are necessary to know if the antiviral activity is due to a synergy between several compounds or due to the presence of other minor compounds.