Hepatoprotection by chemical constituents of the marine brown alga Spatoglossum variabile: a relation to free radical scavenging potential.

Context: In the course of searching hepatoprotective agents from natural sources, the protective effect of chemical constituents of the marine brown alga Spatoglossum variabile Figaro et DE Notar (Dictyoaceae) against CCl₄-induced liver damage in Wistar rats was investigated. The compounds were first investigated for in vitro radical scavenging potential and were also tested for β-glucuronidase inhibition to further explore the relationship between hepatoprotection and antiradical potential.

Methods: The compounds cinnamic acid esters 1 and 2 and aurone derivatives 3 and 4 were first investigated for in vitro radical scavenging potential against 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH), and superoxide anion radicals.

A convenient iodination method for alcohols using cesium iodide/methanesulfonic acid and its comparison using cesium iodide/p-toluenesulfonic acid or cesium iodide/aluminium chloride.

In situ generation of hydrogen iodide from cesium iodide/methanesulfonic acid was found to be an attractive reagent combination for the conversion of alkyl, allyl, and benzyl alcohols to their corresponding iodides under mild conditions. The method is compared with that using cesium iodide/p-toluenesulfonic acid or cesium iodide/aluminium chloride.

Synthesis and biological evaluation of isomeric derivatives of naturally occurring spatozoate.

An isomer of the natural phthalate ester spatozoate (1), n-butyl 2-benzoyloxymethylbenzoate (2a) and a series of its new derivatives 2b-2s were synthesized and exposed to selected biological screening, as phthalates were reported to possess different biological activities. Compound 2g was found to be the most potent cytotoxic agent with a LD50 = 8.98 microg/ml.

Efficient synthesis of isobenzofuran-1(3H)-ones (phthalides) and selected biological evaluations.

The studies presented here deal with the convenient and efficient one-step conversion of o-alkylbenzoic acids into their corresponding isobenzofuran-1 (3H)-ones (phthalides) using NaBrO3/NaHSO3 in a two-phase system. A range of o-alkylbenzoic acids was used with the object of getting a variety of phthalide derivatives as multipurpose biologically active compounds. Seventeen phthalides have been synthesized and tested for cytotoxicity, antibacterial and antifungal activities.

Synthesis, antifungal, and phytotoxic effects of some benzopyrone derivatives.

Syntheses of benzopyrones 1, 13, and their derivatives, as well as their phytotoxic (in vitro) and antifungal (in vitro) screening was carried out. Compounds 2, 7, 8, and 10 showed significant phytotoxic activity, whereas 3, 8, 10, and 12 exhibited significant antifungal (in vitro) activity.

Synthesis and biological screening of 7-hydroxy-4-methyl-2H-chromen-2-one, 7-hydroxy-4,5-dimethyl-2H-chromen-2-one and their some derivatives.

7-Hydroxy-4-methyl-2H-chromen-2-one (2), 7-hydroxy-4,5-dimethyl-2H-chromen-2-one (15) and their some derivatives were synthesized for exploring selected biological screening. The compounds 9 and 13 had shown high degree of cytotoxic activity. Three compound 9, 10 and 13 showed high degree of bactericidal activity amongst the present series.

Synthesis and in vitro leishmanicidal activity of some hydrazides and their analogues.

Twenty-one hydrazides were synthesized by treating different esters with hydrazine hydrate. Substituted hydrazides were obtained by treating hydrazides with alkyl/aryl/acyl halides. Some of these compounds exhibit potential in vitro leishmanicidal activity.

Beta-N-cyanoethyl acyl hydrazide derivatives: a new class of beta-glucuronidase inhibitors.

Eight new beta-N-substituted acyl hydrazides along with their corresponding acyl derivatives were synthesized and screened for in vitro beta-glucuronidase inhibition and found to be active against the enzyme. All of these compounds were found to be noncompetitive inhibitors except for N'-(2-cyanoethyl)-4-hydroxy benzohydrazide (10), which was found to be an uncompetitive inhibitor. Structure-activity relationship studies indicated that the benzyloxy group present in compounds 12 and 13 is responsible for the beta-glucuronidase inhibition activity.

Two new cinnamic acid esters from Marine brown alga Spatoglossum variabile.

Two new natural products, n-butyl and isopropyl 3,5-dimethoxy-4-hydroxycinnamate were isolated from Spatoglossum variabile. Three known compounds, methyl 3,4,5-trihydroxybenzoate, 2-deoxyinosine and 9-beta-(D-ribofuranosyl)adenine were isolated for the first time from the methanolic extracts of this alga. The structure elucidations of the new compounds were carried out with the help of modern spectroscopic techniques.

Syntheses, antibacterial, cytotoxic and antifungal effects of new 3-carboxy-l-phenacylpyridinium salts.

Thirteen pyridine-3-carboxylic acid salt derivatives with various substituted phenacyl residues were prepared and their cytotoxicity, antibacterial and antifungal activities tested. Compounds 5 and 11 proved to be active in the brine shrimp bioassay, compounds 7, 9-12 and 14 showed promising antibacterial activities, whereas none of the compounds tested against 15 fungal cultures proved to be active. Extensive spectroscopic techniques were employed to confirm the structure of the synthetic products.