Hanaa M. Sayed

A new steroid glycoside and furochromones from Cyperus rotundus L.

Further phytochemical investigation of the aerial parts of Cyperus rotundus L. afforded a new steroid glycoside named sitosteryl (6′-hentriacontanoyl)-β-D-galactopyranoside (4) in addition to three furochromones, khellin (2), visnagin (3) and ammiol (9). Furthermore, benzo-α-pyrone (coumarin) (1), salicylic acid (5), caffeic acid (6), protocatechuic acid (7), p-coumaric acid (8), tricin (10) and isorhamnetin (11) were isolated. The structures of these compounds were established by spectroscopic methods. The isolated furochromones were tested for insect antifeedant activity against larvae Spodoptera littoralis when incorporated in artificial diet and offered to larvae in a chronic feeding bioassay. Also, visnagin, khellin and sitosteryl (6′-hentriacontanoyl)-β-D-galactopyranoside showed strong cytotoxic activity against L5178y mouse lymphoma cells and were also active in the brine shrimp lethality test.

Fructose-amino acid conjugate and other constituents from Cyperus rotundus L.

Further phytochemical study on the aerial parts of Cyperus rotundus L. led to the isolation of a fructose-amino acid conjugate, N-(1-deoxy-α-D-fructos-1-yl)-L-tryptophan (16) and its tautomers, in addition to n-butyl-β-D-fructopyranoside (1), ethyl-α-D-glucopyranoside (2), adenosine (3), (−)-(E)-caffeoylmalic acid (4), vitexin (5), isovitexin (6), orientin (7), epiorientin (8), myricetin 3-O-β-D-galactopyranoside (9), luteolin 7-O-β-D-glucuronopyranoside-6″-methyl ester (10), chlorogenic acid (11), luteolin 4′-O-β-D-glucuronopyranoside (12), luteolin 7-O-β-D-glucuronopyranoside (13), uridine (14) and ellagic acid (15). Their structures were elucidated on the basis of spectroscopic methods. Additionally, antioxidant and α-amylase inhibitory activities of some of the isolated phenolic compounds were carried out.

Benzophenone C-glucosides and gallotannins from mango tree stem bark with broad-spectrum anti-viral activity

The high mutation rate of RNA viruses has resulted in limitation of vaccine effectiveness and increased emergence of drug-resistant viruses. New effective antivirals are therefore needed to control of the highly mutative RNA viruses. The n-butanol fraction of the stem bark of Mangifera indica exhibited inhibitory activity against influenza neuraminidase (NA) and coxsackie virus 3C protease. Bioassay guided phytochemical study of M. indica stem bark afforded two new compounds including one benzophenone C-glycoside (4) and one xanthone dimer (7), together with eleven known compounds. The structures of these isolated compounds were elucidated on the basis of spectroscopic evidences and correlated with known compounds. Anti-influenza and anti-coxsackie virus activities were evaluated by determining the inhibition of anti-influenza neuraminidase (NA) from pandemic A/RI/5+/1957 H2N2 influenza A virus and inhibition of coxsackie B3 virus 3C protease, respectively. The highest anti-influenza activity was observed for compounds 8 and 9 with IC50 values of 11.9 and 9.2μM, respectively. Compounds 8 and 9 were even more potent against coxsackie B3 virus 3C protease, with IC50 values of 1.1 and 2.0μM, respectively. Compounds 8 and 9 showed weak cytotoxic effect against human hepatocellular carcinoma and human epithelial carcinoma cell lines through MTT assay.

A new isoflavone from Blepharis ciliaris of an Egyptian origin

A phytochemical study of the aerial parts of Blepharis ciliaris (L.) B.L. Burtt. led to the isolation of one new isoflavone glycoside caffeic acid ester: genistein-7-O-(6″-O-E-caffeoyl-β-d-glucopyranoside) (4), along with seven known compounds: methyl veratrate (1), methyl vanillate (2), protocatechuic acid (3), naringenin-7-O-(3″-acetyl-6″-E-p-coumaroyl-β-d-glucopyranoside) (5), naringenin-7-O-(6″-E-p-coumaroyl-β-d-glucopyranoside) (6), apigenin-7-O-(6″-E-p-coumaroyl-β-d-glucopyranoside) (7), and acteoside (8). Their structures were established on the basis of detailed analyses of physical, chemical, and spectral data. Compounds 1, 2, 3, 6, and 8 were isolated for the first time from this plant. The antioxidant activity of the different extracts as well as for some of the isolated compounds was evaluated.

Noncyanogenic Cyanoglucoside Cyclooxygenase Inhibitors from Simmondsia chinensis.

Two new noncyanogenic cyanoglucoside dimers, simmonosides A and B (1 and 2), were identified from the aqueous extract of jojoba (Simmondsia chinensis) leaves. Compounds 1 and 2 are the first examples of noncyanogenic cyanoglucoside dimers containing a unique four-membered ring, representing novel dimerization patterns at α,β-unsaturated carbons of a nitrile group in 1 and γ,δ-unsaturated carbons in 2. Their structures were elucidated based on spectroscopic evidence and electronic circular dichroism (ECD) calculations. Compounds 1 and 2 exhibit promising COX-2 inhibition activity, with IC50 values of 13.5 and 11.4 μM, respectively.

Ingenines A and B, Two New Alkaloids from the Indonesian Sponge Acanthostrongylophora ingens.

As a continuation of the work on EtOAc fraction of the Indonesian sponge Acanthostrongylophora ingens, 2 new alkaloids: one pyrimidine-β-carboline alkaloid named ingenine A (2) and one pyrimidine-γ-carboline alkaloid named ingenine B (3), along with annomontine (1) were isolated. Their structures were unambiguously established on the basis of NMR spectroscopy ((1) H, (13)C, (1) H-(1) H COSY, HMQC, and HMBC) and mass spectral data. This is the first report of isolation pyrimidine-γ-carboline alkaloid from natural source. Compounds 1 and 3 showed pronounced cytotoxicity against the murine lymphoma L5178Y cancer cell line with ED50 7.8 and 9.1 μg/mL respectively, while compound 2 showed weak activity.

New Nitrogenous Compounds from Anisotes trisulcus

Re-investigation of the methanolic extract of Anisotes trisulcus (Forssk.) Nees aerial parts led to the isolation of two new tricyclic quinazoline alkaloids, 8-amino-7,8,9,11-tetrahydro-6H-pyrido[2,1-b]- quinazoline-2,6-diol (4) and 8-amino-3,6-dihydroxy-7,8,9-trihydro-6H-pyrido[2,1-b]quinazoline- 11-one (5), and two quaternary ammonium compounds, (dimethylamino)-N-(hydroxymethyl)-N,Ndimethyl methanaminium chloride (6) and N-[(carboxyamino)methyl]-N,N-dimethyl ethanaminium chloride (7), together with three known compounds, peganine (1), vasicinone (2), and anisotine (3). The structures of these compounds were established on the basis of physical, chemical, and spectral data (UV, IR, MS, 1D and 2D NMR), as well as by comparison with authentic samples. GC-MS analysis of the fatty acid methyl esters and unsaponifiable matter revealed the presence of 46 fatty acids, 53 hydrocarbons, and 18 sterols. The different extracts were evaluated for their antihyperglycaemic activities. The MeOH, n-hexane, and EtOAc extracts exhibited a significant hypoglycaemic effect

Antioxidant lipoxygenase inhibitors from the leaf extracts of Simmondsia chinensis

OBJECTIVE To isolate and identify chemical constituents with antioxidant and lipoxygenase inhibitory effects of the ethanolic extract of Simmondsia chinensis (Jojoba) leaves. METHODS The alcoholic extract was subjected to successive solvent fractionation. The antioxidant active fractions (chloroform, ethyl acetate and aqueous fractions) were subjected to a combination of different chromatographic techniques guided by the antioxidant assay with DPPH. The structures of the isolated compounds were elucidated on the basis of spectroscopic evidences and correlated with known compounds. The antioxidant activity was assessed quantitively using DPPH and β-carotene methods. The inhibitory potential against enzyme lipoxygenase was assessed on soybean lipoxygenase enzyme. RESULTS Ten flavonoids and four lignans were isolated. Flavonoid aglycones showed stronger antioxidant and lipoxygenase inhibitory effects than their glycosides. Lignoid glycosides showed moderate to weak antioxidant and lipoxygenase inhibitory effects. CONCLUSIONS A total of 14 compounds were isolated and identified from Simmondsia chinensis; 12 of them were isolated for the first time. This is the first report that highlights deeply on the phenolic content of jojoba and their potential biological activities and shows the importance of this plant as a good source of phenolics in particular the flavonoid content.