Alkaloids from the stem bark of Micromelum falcatum.
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Two new quinoldione alkaloids, methyl 2-(3-hydroxy-1-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinolin-3-yl)acetate (1) and 3-hydroxy-1-methyl-3-(2-oxopropyl)quinoline-2,4(1H,3H)-dione (2), and two quinolinone alkaloids previously synthesized but first isolated as natural products, N-methylflindersine (3) and 4-hydroxy-3-methoxy-1-methyl-2(1H)-quinolinone (4), were isolated from the stem bark of Micromelum falcatum, together with the known N-methylswietenidine-B (5). Their structures were established mainly on the basis of 1D- and 2D-NMR techniques. All compounds were evaluated for toxicity towards brine shrimp larvae, and 3 showed strong toxicity with an LD(50) value of 1.39 microg/ml. (+info)
A new acridone alkaloid from Micromelum integerrimum.
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A new acridone alkaloid, 1,3-dihydroxy-4-methoxy-10-methylacridone (1), was isolated from leaves of the plant Micromelum integerrimum, together with two known carbazole alkaloids, glycozolinol (2) and methyl carbazole-3-carboxylate (3). Their structures were elucidated by extensive spectroscopic analysis. (+info)
Anti-tubercular activity of eleven aromatic and medicinal plants occurring in Colombia.
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INTRODUCTION: Human tuberculosis is a contagious-infectious disease mainly caused by Mycobacterium tuberculosis. Although regimens exist for treating tuberculosis, they are far from ideal. Development of effective strategies for treatment of human tuberculosis has posed a challenge, considering the increase in infections associated with the human immunodeficiency virus and immunocompromised patients. Essential oils--volatile, aromatic oil extracts from plants--have been used in traditional treatment of many diseases; however careful investigation of these oils has not been undertaken with respect to treatments of tuberculosis. OBJECTIVE: The in vitro antitubercular activity of essential oils from 11 medicinal plants grown in Colombia were assessed for efficacy as new medications (phytomedicines) for treatment of M. tuberculosis H37Rv. MATERIAL AND METHODS: Essential oil extraction and analysis were performed as described Stashenko et al. (2004). Minimal inhibitory concentrations were determined by a colorimetric macrodilution method, following the protocol described by Abate et al. (1998). Isoniazide and rifampin were used as control treatments. Bactericidal and bacteriostatic activity was measured using the method developed by the Clinical and Laboratory Standards Institute consigned in the M26-A protocol. RESULTS: Essential oils from Achyrocline alata and Swinglea glutinosa were the most active with minimal inhibitory concentrations of 62.5 +/- 0.1 and 100 +/- 36 microg ml(-1), respectively. Carvacrol, thymol, p-cymene, 1,8-cineole, limonene, and beta-pinene were the major components, most often identified in the 11 plant extracts of essential oils. Time-kill curve assays demonstrated the bacteriostatic activity of these essential oils. CONCLUSIONS: The essential oils from A. alata and S. glutinosa plants, and the components identified therein, are candidates as potential phytotherapeutic agents for human tuberculosis control. (+info)
Isolation of acridone alkaloids and N-[(4-monoterpenyloxy)phenylethyl]-substituted sulfur-containing propanamide derivatives from Glycosmis parva and their anti-herpes simplex virus activity.
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Six acridone alkaloids including a new glycosparvarine (1), three limonoids, and four N-[(4-monoterpenyloxy)phenylethyl]-substituted sulfur-containing propanamide derivatives including two new species, (+)-S-deoxydihydroglyparvin (10) and (+)-S-deoxytetrahydroglyparvin (11), were isolated from the branches and the leaves of Glycosmis parva CRAIB collected in the east of Thailand. Antiviral activity evaluation of isolates against herpes simplex virus (HSV) type 1 and 2 disclosed that two acridone alkaloids, glycosparvarine (1) and glycofolinine (4), showed moderate inhibitory activities with 50% effective concentration (EC50) of 348 microM and 151 microM, respectively; as well, (+)-S-deoxydihydroglyparvin (10) exhibited anti-HSV activity at the lower concentration. (+info)
Effect of Thai plant extracts on P-glycoprotein function and viability in paclitaxel-resistant HepG2 cells.
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The effects of ethanol extracts from Thai plants on P-glycoprotein (P-gp) function and cell viability were examined using paclitaxel-resistant HepG2 (PR-HepG2) cells. KP018 from Ellipeiopsis cherrevensis and AT80 from Ancistrocladus tectorius increased both rhodamine 123, a typical P-gp substrate, and [(3)H]paclitaxel uptake in PR-HepG2 cells. However, some extracts such as MT80 from Microcos tomentosa increased rhodamine 123, but not [(3)H]paclitaxel, uptake, while MM80 from Micromelum minutum increased only [(3)H]paclitaxel uptake. Thus, the effects of extracts of Thai plants on rhodamine 123 uptake were not necessarily the same as those on [(3)H]paclitaxel uptake. Purified compounds such as bergapten did not affect the uptake of either substrate. KP018, AT80, and MM80 increased [(3)H]paclitaxel uptake and decreased the cell viability in a concentration-dependent manner. Among these extracts, KP018 showed the most potent cytotoxicity. The cytotoxic potency of KP018 on PR-HepG2 cells was similar to that on wild-type HepG2 cells, and was not potentiated by verapamil. At concentrations resulting in no cytotoxicity, AT80 and MM80 potentiated paclitaxel-induced cytotoxicity in PR-HepG2 cells. These results indicate that K018 may be a useful source to search for a new anticancer drug, while AT80 and MM80 may be useful as modulators of P-gp-mediated multidrug resistance in cancer cells. (+info)
Synthesis and biological properties of benzo-annulated rutaecarpines.
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A series of benzo-annulated rutaecarpines were prepared from anthranilic acid and 3-aminonaphthalene-2-carboxylic acid by Fischer indole synthesis as key reaction. Cytotoxicity was somewhat increased by the introduction of benzo-annulation, which was not directly related to the inhibitory activity against topoisomerases (topo) I and II. Benzo-annulation on ring A led to significant increase of inhibitory activity against topo II while annulations on ring E increased inhibitory activity against topo I. (+info)
Isolation of four new flavonoids from Melicope triphylla.
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Four new flavonoids, 3,5-dihydroxy-7,8-dimethoxy-3',4'-methylenedioxyflavone (1), 3,5-dihydroxy-7-methoxy-3',4'-methylenedioxyflavone (2), 3,5-dihydroxy-7-isopentenyloxy-8-methoxy-3',4'-methylenedioxyflavone (3) and 5-hydroxy-3-isopentenyloxy-7-methoxy-3',4'-methylenedioxyflavone (4), were isolated from the leaves of Melicope triphylla. In addition, two known flavonoids were detected including 5-hydroxy-3,7-dimethoxy-3',4'-methylenedioxyflavone (5) and 5-hydroxy-7-isopentenyloxy-3,8-dimethoxy-3',4'-methylenedioxyflavone (6). The structures of the new compounds were established by spectroscopic methods. (+info)
Alkaloids from stems of Esenbeckia leiocarpa Engl. (Rutaceae) as potential treatment for Alzheimer disease.
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