Records of Natural Products Articles

This paper covers the screening of the secondary plant products to find a cure against cancer which were piled up during the years. In early stages of these studies highly active antitumor glycoproteins were obtained from native Arizona (USA) plants. Later smaller molecules were isolated showing antitumor activity in different test systems. Among these compounds sesquiterpene lactones with an exo-methylene group in the lactone ring, unsaturated diterpenoids and some triterpenoids exhibited activity in vivo and in vitro test systems. A few Colchicum alkaloids showed high activity against murine lymphocytic leukemia (P388). Activity also established in some flavonoidal compounds. Today all around the world research on Natural Products is still going on.

 A new isoflavonolignan glycoside, butesuperin B-7''-O- b -glucopyranoside (1) along with a known isoflavonolignan butesuperin A (2), were isolated from the roots of Sophora tonkinensis. The structure of the new compound was elucidated using spectroscopic methods, mainly 1D and 2D NMR. Compound 1 showed week cytotoxicity against BEL-7404 and NCI-H460 cells in MTT assay.

The aim of this study was to investigate polymeric proanthocyanidin (PA) composition and free radical scavenging activity of leaf, stem bark and fine root of Grevillea robusta. The spectra obtained through MALDI-TOF MS analysis revealed that the examined PAs were built up a mixture of procyanidins and prodelphinidins. Acid-catalyzed cleavage of the PAs coupled with reversed-phase HPLC-ESI-MS showed that the mainconstituents of cleavage products were (epi) gallocatechin benzylthioether and (epi)catechin benzylthioether for leaf and stem bark, and was (epi)gallocatechin benzylthioether for fine root, respectively. The mean degree s of polymerization (mDP) of PAs of leaf, stem bark and fine root were 9.6, 19.0 and 10.1, respectively. The PAs extracted from leaf, stem bark and fine root exhibit ed higher antioxidant activity than those of ascorbic acid and synthetic antioxidant butylated hydroxyanisole (BHA) , as measured by 2,2 '-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging method.

One new cycloartane-type saponin, 3-O-[ β -D-xylopyranosyl-(1 → 2)- β -D-xylopyranosyl]-6-O- β -D-glucuronopyranosyl-3 β ,6 α ,16 β ,24(S),25- pentahydroxyxyxloartane (1) was isolated from the MeOH extract of whole plant parts of Astragalus erinaceus along with 5 known saponins (2-6), cyclodissectoside, cycloastragenol, 6-O- β -D-glucopyranosyl-3 β ,6 α ,16 β ,24(S),25-pentahydroxycycloartane, oleifolioside B and 3,6-di-O- β -D-xylopyranosyl-3 β ,6 α ,16 β ,24(S),25-pentahydroxycycloartane, respectively. Their structures were established by the extensive use of 1D- and 2D-NMR experiments along with ESIMS and HRMS analysis. The glucuronic acid moiety in cycloartanes is a very unusual finding.

Two new coumarin glycosides, 6-methoxy-5,7-dihydroxy-3,4-dihydrocoumarin-8-C-glucopyranoside (1) and 5-vinyl-6,7-dimethoxy-3,4-dihydrocoumarin-8-C-glucopyranoside (2), along with four known flavonoid compounds, were isolated from the aerial parts of Diceratella elliptica (DC.) Jonsell growing in Egypt. Their structures were established on the basis of detailed chromatographic and spectroscopic techniques (UV, 1D NMR, 2D NMR, and ESIMS). Compounds 1 and 2 were evaluated for their cytotoxic activity and showed relatively high activity against three human carcinoma cell lines; liver (HEPG2), cervix (HELA) and colon (HCT116).

A series of ocotillol-type derivatives bearing a glycosyl moiety were synthesized. Among them, compound 3a and 3b led to a reduction in the increased CK, LDH, MDA activity and attenuate the decrease of SOD, GSH-PX and T-AOC compared with the iso group. In the heart section, compound 3aand 3b group showed nearly normal myofibrillar structure nearly without neutrophil granulocytes infiltration in the iso group. These results indicated that ocotillol-type derivatives may be the good lead compounds with protective property of myocardial ischemia.

Two new phorbol-type diterpene esters has been isolated from the chloroform extract of the leaves of Synadenium grantii Hook F. and identified as 3,4,12,13-tetraacetylphorbol-20-phenylacetate and 4-deoxyphor bol-12,13-ditiglate for which the trivial names Synagrantol A & B respectively, were adopted. Furthermore, two known triterpenes were isolated. The structures of all isolated compounds were established by 1D and 2D NMR spectroscopy including 1H and 13C NMR, HSQC and HMBC techniques. The cytotoxicity as well as the antiparasitic activity of the chloroform extract was performed and proved to be active.

Crataegus species (Rosaceae), known as “Howthorn” have found special medicinal use for the treatment of mild heart diseases. This work aims to measure the antioxidant capacities of various Crataegus species growing in Turkey . In this study, the flowers and leaves from 52 samples belonging to 17 taxa of 14 Crataegus species naturally growing in Turkey have been investigated for their antioxidant activity/capacity. Four different methods (CUPRAC, FRAP, ABTS/Persulfate and Folin: FCR assays) were used for determination of the antioxidant capacities of the samples. The leaves and the flowers of the plants were studied separately. Samples representing the same species collected from different locations were studied separately. The results have indicated that the samples differing by some minor morphological characteristics exhibit considerably different antioxidant capacities. Among the flower samples, the most effective species was C. × sinaica Boiss. nothosubsp. sinaica and among the leaf samples C. pentagyna Waldst and Kit. ex. Willd. were the most active. Generally, C. monogyna Jacq. samples have exhibited markedly high antioxidant activity. Moreover, the species collected from Bolu district (surrounded by several forest s and lake s) have shown significantly high activity regardless of the species differences among the samples.

This study is designed to examine the chemical composition and in-vitro antioxidant activity of the essential oils of Salvia palaestina (Bentham) and S. ceratophylla (L.). GC-EIMS analyses of the essential oils were resulted in the determination 70 and 53 different compounds, representing 92.50% and 95.80% of the total oils, respectively. In S. palaestina oil, t he major compounds were caryophyllene oxide (16.1%) and (E)-caryophyllene 4.5%). In the latter case g -muurolene (11.4%) and α-pinene (7.6%) were the major compounds. Antioxidant activities of the samples were determined by four different test systems namely β-carotene/linoleic acid, DPPH, reducing power and chelating effect. In all systems, S. palaestina oil showed greater activity profile than that of S. ceratophylla. None of the essential oils showed metal chelating effect.

 Eight compounds were isolated from the stems of Alyxia reinwardtii, namely coumarin (1), 3-hydroxycoumarin (2), 6-hydroxycoumarin (3), 8-hydroxycoumarin (4), scopoletin (5), (+)-pinoresinol (6), zhebeiresinol (7) and p-hydroxybenzoic acid (8). The structures of all compounds were characterized by means of NMR, MS, chemical analysis and comparison with the literature data. The structure of compound 7 was also confirmed by X-ray crystallography. To the best of our knowledge, compounds 2-3, 5 and 7-8 have been isolated for the first time from this species. In terms of antioxidant activity, the isolated compounds were evaluated by various in vitro model assays, which include the DPPH radical scavenging activity, xanthine oxidase-related activity (superoxide scavenging activity and inhibitory effect on xanthine oxidase) and lipid peroxidation inhibitory activity.

 The investigation of the aerial parts of Centaurea omphalotricha Coss. & Durieu ex Batt. & Trab. allowed the isolation of nine secondary metabolites corresponding to five flavonoids: oroxylin A (1), chrysin (2), tenaxin II (3), 5,7,2’-trihydroxyflavone (4) and quercetin (5), and four triterpenoids: lupeol (6), taraxasterol (7), daucosterol (8) and β-sitosterol (9). Their structures were established by spectroscopic methods such as 1H and 13C NMR, COSY, HSQC, and HMBC experiments, and ESI-MS, and comparison with literature data. The flavonoids tenaxin II (3) and 5,7,2’-trihydroxyflavone (4) are new for the genus Centaurea L.

The methanol extract of P. nisidai leaves yielded a benzophenone rhamnoside , iriflophenone 2-O-α-L-rhamnopyranoside (1) in addition to g enkwanin 5-O-β-D-primeveroside (2) and mangiferin (3). The isolated compounds as well as the derived aglycones of 1 and 2 assigned as compounds 4 and 5, respectively, were tested for their estrogenic activity on ERα using an estrogen receptor competitive binding screen. Compounds 1 , 4 and 5 showed almost the same binding ability to ERα with IC 50 of 630 µM, 700 µM and 800 µM, respectively. Virtual docking with ERα revealed that compound 1, 4 and 5strongly hydrogen bond with amino acids Glu353, Arg349, Gly521 and His524, in the estrogen receptor ligand binding domain, similar to that of mammalian estrogen 17β-estradiol.

Acanthus montanus (Nees) T. Anders. (Family: Acanthaceae) is a small shrub with sparse branches and soft stems, widespread in Africa, the Balkans, Romania, Greece and Eastern Mediterranean. Documented evidence showed that the leaves of the plant possess spasmolytic, analgesic, anti-inflammatory and antipyretic activities. In our ongoing research project; aimed at identifying new natural compounds with insecticidal activity, the alcohol extract of the aerial parts of A. montanus exhibited a significant activity against adult Aedes aegypti. Phytochemical study of the plant has resulted in isolation of nine compounds, eight of which exhibit variable degrees of insecticidal activity. β-sitosterol-3-O- β –D-glucoside (1) exhibited potent mosquitocidal activity (100% mortality) against adult Aedes aegypti at 1.25 μg/mg concentration, followed by palmitic acid (2) (90%), linaroside (3) (80%), and acetoside (9) (70%) respectively. It is noteworthy that this is the first report of insecticidal activity of β-sitosterol-3-O- β –D-glucoside, linaroside and acetoside.

Essential oil extracted from dried aerial parts of Teucrium flavum ssp. flavum harvested in Zakynthos, Greece, was analysed by gas phase chomatography (GC) and gas chomatography mass spectrometry (GC-MS). The main constituents were caryophyllene (13.5%), caryophyllene oxide (8.5%), 4-vinyl guaiacol (6.0%) and α-humulene (5.0%).

 A chemosystematic survey was carried out to specify whether leontopodic acid and leontopodic acid B, two unique caffeoyl-D-glucaric acid derivatives, recently identified in the emblematic alpine edelweiss (Leontopodium alpinum Cass.) are also found in members of the genus Gnaphalium from the Alps. Gnaphalium is closely related to Leontopodium and both genera are assigned to the Gnaphaliinae subtribe (Asteraceae, Gnaphalieae). In all investigated Gnaphalium species, G. hoppeanum W.D.J.Koch, G. norvergicum Gunnerus, G. supinum L., G. sylvaticum L., and G. uliginosum L., both leontopodic acid and leontopodic acid B were detected. Moreover, a number of related compounds were detected by HPLC/MS and their assumed structures are discussed. The chemosystematic data reported here are of interest to explore new sources for the biologically active compounds leontopodic acid and leontopodic acid B and they also hint to the occurrence of novel caffeoyl-D-glucaric acid derivatives in Gnaphalium not detected in Leontopodium, yet.

The composition of the essential oils obtained by hydrodistillation from different parts of Bupleurum rotundifolium L. including roots, flowers and fruits were investigated by GC and GC/MS systems, simultaneously . The antibacterial activity of the oils was assessed with micro-dilution assays. The results showed large variations in the composition of the oils. The main components of the plant were undecane (26.4%) and tridecane (12.3%) in roots, hexadecanoic acid (12.2%) in flowers and α-pinene (11.0%) in fruits. The essential oils of B. rotundifolium obtained from flowers and fruits used in the study did not have any effect against bacteria. MIC values for the bacterial strains tested, which were sensitive to the essential oil of roots of B. rotundifolium , were in the ratio of 2 mg/mL. This investigation showed that the antibacterial activity of B. rotundifolium was attributed to the essential oil of roots, thus they can be a potential medicinal resource.