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  • Author: Orlando Muñoz x
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Abstract

Four known tropane alkaloids were isolated from the leaves of the endemic Chilean plant Latua pubiflora (Solanaceae). For the first time; 3α-cinnamoyloxitropane and apoatropine are reported in this plant. Scopolamine and hyoscyamine were previously reported.

Stress, pathogens or insects induce profound changes in the expression of the chemical constituents of plants. Some of these changes could be adaptations to the new conditions or the expression of new defensive characteristics. The purpose of this paper was to analyze the effect of aphid infestation on the composition of endogenous compound, in barley leaves. Leaf waxes were obtained by washing with dichloromethane and remaining compounds were extracted with ethyl acetate and ethanol from homogenized leaves. The identification of compounds was done by combined capillary gas chromatography and mass spectrometry. Epicuticular compounds detected in barley after 6 days of aphid infestation were as follows (%): (1) 1-docosene (1.98), (2) 1-octadecene (2.07), (3) phytol (0.81). Epicuticular compounds in non-infested plants were (4) isophytol (0.83), (5) N-cyclohexyl-cyclohexanamine, (0.11) (6) 5-pentadecyl-1,3-benzenediol (2.10). In ethyl acetate extracts from infested plants the main compounds were: (1) (2.02), (7) 2,5-diethylpyrazine (0.61), (8) (5E)-eicosene (1.61), (9) (3E)-eicosene (1.93), (10) (9E)-eicosene (1.80). In non-infested plants the only detected compounds were (1) (1.02), (6) (1.91), and (7) (0.43). In methanol extracts from infested plants the following compounds were identified: (6) (2.15), (7) (0.21), (11) 2,2,6.6 tetramethyl- piperidine (0.12), (12) indole (1.01), (13) heptadecane (0.10), (14) methyl-β-ᴅ-glucopyranoside (0.21), (15) 2,5- dihydroxybenzaldehyde (0.27) and (16) N-phenyl-2-naphthalenamine (0.29). In polar extracts from non-infested plants the most abundant compounds were (4) (1.40), (7) (0.18), (17) (9Z,12Z,15Z)-octadecatrienoic methyl ester (1.01), (18) (9Z,15Z)- octadienoic methyl ester (2.01), and (19) hexadecanoic methyl ester (1.93). Compounds 4, 5 and 7 -1 9 are described for the first time in Hordeum vulgare.

Three triterpenoid quinonemethides. one triterpene (β-amyrin) and three phenolic compounds were isolated from the roots of Maytenus chubutensis (Speg.) Lourt., O’Don. et Sleum. and Maytenus disticha (Hook. f.) (Celastraceae). The triterpenoid quinonemethides were identified as tingenone, celastrol and pristimerin. The triterpenoid was identified as β-amyrin and phenolic compounds were identified as catechin, galocatechin and (-)epicatechin

Abstract

Monomelittoside, melittoside, 8-acetyl-harpagide, har­pagide, ajugol, 5-desoxy-harpagide, 5-desoxy-8-acetyl-harpagide and catalpol were isolated from the aerial parts of S. grandidentata.

The extracts of several plants of Central Chile exhibited anti-Trypanosoma cruzi trypomastigotes activity. Most active extracts were those obtained from Podanthus ovatifolius, Berberis microphylla, Kageneckia oblonga, and Drimys winteri. The active extract of Drimys winteri (IC50 51.2 μg/mL) was purifi ed and three drimane sesquiterpenes were obtained: polygodial, drimenol, and isodrimenin. Isodrimenin and drimenol were found to be active against the trypomastigote form of T. cruzi with IC50 values of 27.9 and 25.1 μM, respectively.

Muehlenbeckia hastulata (J. E.Sm.) Johnst. used mainly for its abortive properties was found active for oxytoxic and analgesic activities in a biological activity screening (oxytoxic, analgesic, antimicrobial, cytotoxic and xanthine oxidase assay). Epicatechin, emodin-8-glycoside and rutin were isolated from the aerial part and the root of the plant.

Abstract

Pinocembrin, acacetin, galanguin, izalpin, kaempferide, prenyletin and diarytheptane were isolated from propolis from Central Chile.

Abstract

Viscidone (0.5%), vanillin, 3',4'-(methylendioxy)acetophenone, 3-ethoxy-4-methoxybenz-aldehyde, cinnamic acid, 3-methoxy-4-hydroxymethyl ester were isolated from propolis of hives from Cuncumen. This is the first report on propolis composition of an arid and a Mediterranean type climate area.

The relative lack of specifi city of atropine as a competitive antagonist of muscarinic receptors is a frequent cause of undesirable parasympathetic side effects. Consequently, new tropane alkaloids with potentially greater selectivity are usually seen with real interest. The cholinergic antagonistic effects of a purifi ed mixture of tropane alkaloids extracted from Schizanthus hookeri were evaluated in rat ileum. For this purpose, ileal segments were obtained from randomly selected male Sprague-Dawley rats, and the effect of 1 · 10−4, 1 · 10−3, and 1 · 10−2 mg/mL of the purifi ed mixture of alkaloids on the contractile response of the ileum induced with increasing doses of carbachol (5 · 10−8 − 8 · 10−4 M) was determined. The results were compared with those obtained in the presence of 3.46 · 10−7, 3.46 · 10−6, and 3.46 · 10−5 mg/mL atropine as an agonist. Tropane alkaloids extracted from Schizanthus hookeri competitively antagonized acetylcholine muscarinic receptors.

Abstract

A novel cucurbitacin glycoside has been isolated from aerial parts of Kageneckia oblonga R. et P. and shown to be 3β-(β-D-glucosyloxy)-16α,23α-epoxycucurbita-5,24-dien-11-one. The structure was established by usual spectroscopic and two-dimensional (2D ) NMR techniques. This compound has found to be nontoxic when tested in-vivo cell culture assays. In previous investigations we reported 23,24-dihydrocucurbitacin F and prunasine. This was the first report on cucurbitacins from the genus Kageneckia (Rosaceae).