Phytochemical and biological evaluation of Buddleja polystachya growing in Saudi Arabia.

Several Buddleja species were the target of phytochemical and biological studies; however, nothing was reported concerning the chemistry of Buddleja polystachya Fresen. growing in Saudi Arabia. Sixteen constituents were isolated from the aerial parts of B. polystachya using various chromatographic techniques and were identified by the help of different spectral techniques including 1D, 2D NMR and mass spectrometry. Moreover, the different fractions were evaluated for their anti-inflammatory and hypoglycemic activities. The isobenzofuranone derivative (4-hydroxy-7-methylisobenzofuranone) (4), has been isolated for the first time from this natural source, B. polystachya, along with fifteen known compounds namely; phenolic fatty acid ester, 1'(4-hydroxyphenyl) ethanol ester of docosanoic (1), uvaol (2), sakuranetin (3), kumatakenin (5), cirsimaritin (6), 5-hydroxy-3,7,4'-trimethoxyflavone (7), oleanolic acid (8), herbacetin 3,7,8-trimethyl ether (9), ursolic acid (10), verbascoside (11), linarin (12), luteolin 7-O-ß-D-glucoside (13), luteolin 7-(6"-caffeoyl)-O-ß-D-glucopyranoside (14), luteolin (15), and 6-O-α-L-(4''-O-trans-cinnamoyl) rhamnopyranosylcatalpol (16). Regarding the biological activities investigated, the ethyl acetate fraction showed the most significant anti-inflammatory activity, followed by the n-butanol and the aqueous fractions. As for the petroleum ether and dichloromethane fractions, their anti-inflammatory effects were moderate. The highest hypoglycemic activity was possessed by the ethyl acetate fraction, followed by the dichloromethane fraction and the n-butanol fraction showed the weakest activity.

Acetylcholine esterase inhibitory activity of green synthesized nanosilver by naphthopyrones isolated from marine-derived Aspergillus niger.

Aspergillus niger metabolites exhibited a wide range of biological properties including antioxidant and neuro-protective effects and some physical properties as green synthesis of silver nanoparticles AgNP. The present study presents a novel evidence for the various biological activities of green synthesized AgNPs. For the first time, some isolated naphtho-γ-pyrones from marine-derived Aspergillus niger, flavasperone (1), rubrofusarin B (2), aurasperone A (3), fonsecinone A (4) in addition to one alkaloid aspernigrin A (7) were invistigated for their inhibitory activity of acetylcholine esterase AChE, a hallmark of Alzheimer's disease (AD). The ability to synthesize AgNPs by compounds 3, 4 and 7 has been also tested for the first time. Green synthesized AgNPs were well-dispersed, and their size was ranging from 8-30 nm in diameter, their morphology was obviously spherical capped with the organic compounds. Further biological evaluation of their AChE inhibitory activity was compared to the parent compounds. AgNps dramatically increased the inhibitory activity of Compounds 4, 3 and 7 by 84, 16 and 13 fold, respectively to be more potent than galanthamine as a positive control with IC50 value of 1.43 compared to 0.089, 0.311 and 1.53 of AgNPs of Compounds 4, 3 and 7, respectively. Also compound 2 showed moderate inhibitory activity. This is could be probably explained by closer fitting to the active sites or the synergistic effect of the stabilized AgNPs by the organic compouds. These results, in addition to other intrinsic chemical and biological properties of naphtho-γ-pyrones, suggest that the latter could be further explored with a view towards other neuroprotective studies for alleviating AD.

Dibenzocyclooctadiene lignans from Kadsura philippinensis.

Lignans with the dibenzocyclooctadiene skeleton, kadsuphilols I-L, and one C(19)-homolignan, kadsuphilol M, were isolated by chromatographic fractionation of an ethyl acetate extract of the aerial parts of Kadsura philippinensis. Their structures were elucidated through extensive spectroscopic methods, including HRESIMS and 2D NMR experiments (HMQC, COSY and HMBC). The stereochemistry at the chiral centers and the biphenyl moist, were determined using NOESY, as well as analysis of CD spectra, respectively. The relative configuration of heteroclitin J was confirmed by single crystal X-ray crystallographic analysis. The in vitro radical-scavenging activities of these compounds by using DPPH were evaluated.

Sinuladiterpenes A-F, new cembrane diterpenes from Sinularia flexibilis.

Chromatographic investigation of the octocoral Sinularia flexibilis afforded six new cembrane diterpenes, sinuladiterpenes A-F (1-6, resp.), in addition to four known cembranolides, 11-episinulariolide acetate, 11-dehydrosinulariolide, 11-episinulariolide, and sinulariolide. Their structures were elucidated by spectroscopic analysis, especially 2D-NMR and HR-ESI-MS. Compound 2 exhibited significant in vitro cytotoxic activity against human colon adenocarcinoma (WiDr) cell line.

Cembrane diterpenoids from the taiwanese soft coral Sarcophyton stolidotum.

Investigation of an EtOAc-soluble extract of the soft coral Sarcophyton stolidotum resulted in the isolation of seven new 14-membered carbocyclic cembranes, sarcostolides A-G (1-7), together with two known cembrane diterpenes, isosarcophytoxide and isosarcophine. The structural elucidation of these metabolites was determined on the basis of spectroscopic analyses, particularly 2D NMR techniques. Sarcostolide E (5) exhibited weak to moderate cytotoxic activity against human WiDr and Daoy tumor cell lines. A biogenetic pathway and relationship for compounds 1-7 was also proposed.

Frajunolides E-K, briarane diterpenes from Junceella fragilis.

Chemical investigation of the gorgonian octocoral Junceella fragilis, collected in Taiwan, resulted in the isolation of seven new briarane-type diterpenes, frajunolides E-K (1-7), in addition to 14 known briaranes, praelolide, junceellin, junceellolides A-E, and K, 11a,20a-epoxy-4-deacetoxyjunceelolide D, umbraculolide A, junceellonoid A, and juncins Y, Z, and ZI, as well as ergosterol peroxide. The structures of 1-7 were determined by analysis of HRESIMS and 2D NMR spectroscopic data. Cytotoxicity and in vitro anti-inflammatory activities of compounds 1-7 were also evaluated.

New bioactive clerodane diterpenoids from the roots of Casearia membranacea.

Bioassay-guided fractionation of the acetone extract of the roots of Casearia membranacea furnished three new clerodane diterpenes, caseamembrins S-U (1-3) and the known caseamembrin Q (4). Their structures were established by extensive spectroscopic analyses, especially 2D-NMR. Compounds 1-4 were tested against human tumor cells, including HeLa (cervical epitheloid carcinoma), DLD-1 (colon carcinoma), Daoy (medulloblastoma), and KB (oral epidermoid carcinoma) cell lines. Caseamembrin T (2) exhibited the most potent activity against Daoy cells (ED(50)=10 ng/ml), superior to that of the standard drug mitomycin.

Bioactive marine prostanoids from octocoral Clavularia viridis.

Chemical investigation of the nonpolar extract of soft coral Clavularia viridis resulted in isolation of five new prostanoids, designated as claviridic acids A-E (1-5, resp.), in addition to the known clavulones I-III. Their structures were determined on the basis of spectroscopic techniques, especially HR-ESI-MS, CD, and 2D-NMR experiments. The isolated marine prostanoids exhibited potent inhibitory effect on PHA-induced proliferation of peripheral blood mononuclear cells (PBMC), as well as significant cytotoxic activity against human gastric cancer cells (AGS).

Two new xeniolides from a Taiwanese Xenia soft coral.

Chromatographic investigation of an extract of the octocoral Xenia umbellata afforded two new diterpenes, xenibelatols A (1) and B (2), in addition to three known xenicane diterpenes, 7,8-oxidoisoxeniolide (3), 9-hydroxyxeniolide F (4), and florlide C, and a cadinene sesquiterpene, xenitorin A (5). The structures were elucidated through spectroscopic analysis, especially 2D NMR.

Benzylamides from Salvadora persica.

A phytochemical investigation of stems from Salvadora persica resulted in the first isolation of four benzylamides from a natural source. The isolated compounds were identified as butanediamide, N1,N4-bis(phenylmethyl)-2(S)-hydroxy-butanediamide (1), N-benzyl-2-phenylacetamide (2), N-benzylbenzamide (3) and benzylurea (4). The structure elucidation was accomplished using spectroscopic methods, especially 2D NMR and HREIMS. Compound 2 revealed a significant inhibitory effect on human collagen-induced platelet aggregation, and a moderate antibacterial activity against Escherichia coli.

Isolation of aureol from Smenospongia sp. and cytotoxic activity of some aureol derivatives.

The sesquiterpene aureol (1) was isolated by chromatographic fractionation of a non-polar extract from Smenospongia sp. Methylation of aureol yielded 5'-O-methyl-aureol (2) while the prepared acylation products of aureol were 5'-O-acetyl-aureol (3), 5'-O-benzoyl-aureol (4), 5'-O-(4-fluoro-benzoyl)-aureol (5), 5'-O-(4-chlorobenzoyl)-aureol (6), 5'-O-(4-methylbenzoyl)-aureol (7), 5'-O-nicotinoyl-aureol (8), aureol-N,N-dimethylthiocarbamate (9), 5'-O-(2-furoylcarbonyl)-aureol (10), 5'-O-(2-thienoylcarbonyl-aureol (11). The structures of aureol as well as its ten derivatives were established through spectral analysis. The in vitro cytotoxic activities of the eleven compounds were evaluated against Hepa59T/VGH, KB and Hela tumor cell lines.

New gemacranolides from Eupatorium hualienense.

Phytochemical investigation of Eupatorium hualienense (C. H. Ou, S. W. Chung, C. I. Peng) has resulted in the isolation of the new sesquiterpene lactones 1-5, named eupahualins A-E, along with the known heliangolide eupasimplicin B (6). The structures of the isolated compounds were established through detailed spectral analyses, especially by means of 2D-NMR techniques. Compounds 1-4 and 6 showed significant activities against cell lines of human chronic myelogenous leukemia (K562) and human bone cancer (U2OS).

Chemical constituents from the Hydrangea chinensis.

Two quinazolone alkaloids, (+)-febrifugine (1) and isofebrifugine (2), along with three coumarin derivatives, 6-hydroxy coumarin (3), skimmin (5), and umbelliferone-7-O-alpha-L-rhamnopyranosyl(1-->4)-beta-D-glucopyranoside (6), were isolated from the roots of Hydrangea chinensis. Compound 6 is a new compound. In addition, umbelliferone (4), linoleic acid (7), two steroidal glycosides (8, 9), three furfural derivatives (10-12), and butyl-beta-D-fructofuranoside (13) were isolated from the leaves of the same plant. The structures of all isolates were elucidated by spectral methods.

Antiplatelet and anti-HIV constituents from Euchresta formosana.

Phytochemical investigation of the methanol extract of Euchresta formosana resulted in the isolation of thirty-four compounds. Compounds 1, 3-12, 15, 27, 29 and 32-24 were isolated from this species for the first time. These compounds were identified by spectral analyses and tested for antiplatelet aggregation and anti-HIV activities. Among these compounds, tectorigenin (1), 3',4',5-trihydroxyisoflavone (3), and euchretin F (19) were the most effective antiplatelet aggregation compounds; they inhibited both AA- (arachidonic acid) and collagen-induced platelet aggregation. Meanwhile, flemiphyllin (B), quercetin (13), euchretin M (23), and formosanatin C (26) inhibited HIV replication in H9 lymphocyte cells.

Tasumatrols U-Z, taxane diterpene esters from Taxus sumatrana.

Phytochemical investigation of the leaves and twigs of Taxus sumatrana afforded six new taxane diterpene esters, tasumatrols U-Z ( 1- 6). Compounds 2 and 5 contained a rare five-membered lactone ring at C-8, C-9, C-10, and C-19. The structures were established on the basis of detailed spectroscopic analyses, particularly HRESIMS and 2D NMR techniques. Compound 5 showed cytotoxicity against a human hepatoma (Hep2) cell line.

Kadsuphilols A-H, oxygenated lignans from Kadsura philippinensis.

Eight new oxygenated lignans, kadsuphilols A-H (1-8), were isolated from the leaves and stems of Kadsura philippinensis. Four of the isolated lignans (1-4) possess the normal C18-dibenzocyclooctadiene skeleton, while the other four lignans (5-8) are C19-homolignans possessing a substituted cyclohexadienone ring with a spiro-benzofuranoid moiety. The structures of the isolated metabolites were elucidated through spectroscopic analyses, including 2D NMR experiments. Compounds 1 and 4 are the first report of an R-biphenyl configuration with a beta-oxygenated substituent at the C-9 position. The in vitro radical-scavenging activities of these compounds using DPPH were tested and evaluated. Compound 3 exhibited more potent activity than vitamins C and E.

Chemical transformation and biological activities of ambrein, a major product of ambergris from Physeter macrocephalus (sperm whale).

Ten new derivatives (2-11) of ambrein (1), isolated from ambergris, were prepared by chemical transformation. Oxidation and/or cyclization were effected by reactions with selenium oxide or p-toluenesulfonyl chloride or with the use of shortwave UV light. The structures of 2-12 were elucidated by spectroscopic analysis, with the structure and relative configuration of 9 confirmed by single-crystal X-ray crystallography. The cytotoxic activities of 1-12 were investigated against human liver carcinoma (Hepa59T/VGH), colon adenocarcinoma (WiDr), lung carcinoma (A-549), and human breast adenocarcinoma (MCF-7) cell lines. The anti-inflammatory activities of 1-11, in terms of the inhibition of human neutrophil function, were also evaluated.

Xenicane-type diterpenes with cytotoxicity from Xenia florida.

Chromatographic investigation of an acetone extract of the octocoral Xenia florida afforded three new xenicane diterpenes, namely, florxenilide A (1), florxenilide B (2), and florxenilide C (3), in addition to seven known xenicane diterpenes and two known cadinene sesquiterpenes. Structures were elucidated through spectroscopic analysis, especially 2D NMR, and chemical derivatization. The absolute configuration of 1 was determined by NOESY, CD, and Mosher's methods. Florxenilides A (1) and B (2) exhibited cytotoxicity against human colon cancer (WiDr) cells at 4.5 and 3.7 muM, respectively.

Bioactive pyranoxanthones from the roots of Calophyllum blancoi.

Phytochemical investigation of the roots of Calophyllum blancoi growing in Taiwan resulted in the isolation of three new pyranoxanthones, blancoxanthone (1), acetyl blancoxanthone (2) and 3-hydroxyblancoxanthone (3), in addition to two known pyranoxanthones, pyranojacaeubin (4) and caloxanthone (5). Structural characterization of the isolated compounds was determined by spectral analyses especially 2-D NMR. Biological study of the isolated xanthones revealed that blancoxanthone (1) exhibited significant anti-coronavirus activity.

Cytotoxic sesquiterpene lactones from Eupatorium kiirunense, a coastal plant of Taiwan.

Phytochemical investigation of Eupatorium kiirunense has resulted in the isolation of eight new sesquiterpene lactones, constituted by five germacranolides, eupakirunsins A-E (1-5), and three heliangolides, eupaheliangolide A (6), 15-acetoxyheliangin (7), and 3-epi-heliangin (8), in addition to the known heliangin (9) and 8,10-epoxy-9-acetoxythymol angelate (10). The structures of the new compounds were established through detailed analysis of their spectroscopic data. Compounds 6, 8, and 9 exhibited cytotoxicity against human oral epidermoid (KB), cervical epitheloid (Hela), and liver (hepa59T/VGH) carcinoma cells.