Mireya Correa

A search for anti-viral properties in Panamanian medicinal plants.: The effects on HIV and its essential enzymes

Aqueous and methanolic extracts of 39 Panamanian medicinal plants were tested for anti-human immunodeficiency virus (HIV) effects. The extracts were tested for the inhibition of HIV-induced cytopathic effects in cultured cells, HIV-reverse transcriptase (RT) and HIV-protease (PR) enzymes. The water extract of the branches of Jatropha curcas (Euphorbiaceae) inhibited strongly the HIV-induced cytopathic effects with low cytotoxicity. On the other hand, the water extracts of the whole plant of Chamaesyce hyssopifolia (Euphorbiaceae), the leaves of Cordia spinescens (Boraginaceae) and the aerial parts of Hyptis lantanifolia (Labiatae), and the methanol extract of the aerial parts of Tetrapteris macrocarpa (Malpighiaceae) were potent inhibitors of HIV-RT (IC50: 6-8 microg/ml). Seven out of 39 plants were found to be moderate inhibitors of HIV-PR (IC50: 43-100 microg/ml). Furthermore, we report on the respective inhibitory substances of J. curcas, C. hyssopifolia and C. spinescens, and their possible mechanism of action.

Ethnobotanical inventory of medicinal plants used by the Guaymi Indians in Western Panama. Part II

A list of newly identified plants is presented to supplement Part I (Joly et al. (1987) Journal of Ethnopharmacology 20, 145-171). A comparative analysis is made between our work and two other recent inventories of plants used by the Guaymi Indians of Panama and Costa Rica. As in Part I, the results of a literature survey are also provided, including medicinal uses, known constituents and pharmacological effects.

ALKALOIDS AND OTHER COMPOUNDS FROM PSYCHOTRIA CORREAE

Abstract From extracts of the leaves and/or the roots of Psychotria correae , isodolichantoside and the new alkaloids correantoside, 10-hydroxycorreantoside, correantines A to C, and 20-epi-correantine B were isolated, in addition to two cerebrosides and some isoprenoids. Structures were established by spectroscopic studies in combination with chemical interconversions and partial synthesis.

Using ecological criteria to design plant collection strategies for drug discovery

Tropical forests are one of the most diverse and endangered habitats on earth. They have also been portrayed as a source of future pharmaceuticals, yet finding useful compounds can be both scientifically and politically challenging. Increasingly, over the past decade, the potential value of medicinal compounds derived from plants, microorganisms, and animals has been proposed as a tangible benefit of biodiversity, and therefore a basis for promoting its preservation. Ecological theories of plant defense can increase the probability of discovering compounds with activity in bioassays against human disease targets. In addition, conducting research in tropical countries with local scientists provides immediate and lasting benefits for the sustainable use of biodiversity. This new approach to drug discovery has been effective in identifying bioactive leads. It is both an important step towards understanding the medicinal value of biodiversity, and a practical way to link drug discovery with conservation.

Ethnopharmacognostic Observations on Panamanian Medicinal Plants. Part I

(1979). Ethnopharmacognostic Observations on Panamanian Medicinal Plants. Part I. Quarterly Journal of Crude Drug Research: Vol. 17, No. 3-4, pp. 115-130.

Distribution and taxonomic significance of calystegines in the convolvulaceae

Abstract The GC-MS analysis of 65 convolvulaceous species from many, predominantly tropical provenances, belonging to 22 genera (9 tribes), revealed the occurrence of one to five calystegines in 30 species belonging to 15 genera (8 tribes). This indicates the chemotaxonomic significance of these glycosidase inhibiting polyhydroxy-nortropanes for the Convolvulaceae.

Screening of Latin American Plants for Cytotoxic Activity

Abstract The SRB cytotoxicity assay was used to screen plant extracts, in a collaborative multinational OAS project involving Argentina, Bolivia, Colombia, Costa Rica, Guatemala, Nicaragua and Panama, against breast (MCF-7), lung (H-460), and central nervous system (SF-268) human cancer cell lines. Out of 310 species tested, 23 (7.4%) plants showed cytotoxic activity at GI50 values ≤10 µg/ml. The most active plants were Thevetia ahouai., Physalis viscosa., Piper jacquemontianum., Piper barbatum., Senna occidentalis., Tovomita longifolia., and Lippia cardiostegia.. Blepharocalyx salicifolius. and Senna occidentalis. were selectively active against one cell line, SF-268 or MCF-7, respectively. Within the framework of this project, 14 compounds have been isolated, 5 new (4 benzophenones, coumarin) and 9 known to the literature. But only the bioassay-guided fractionation of the active extract of Piper barbatum. leaves, which led to the isolation of three known compounds: (2′E., 6′E.)-2-farnesyl-1,4-benzoquinone (1), (2′E., 6′E.)-2-farnesylhydroquinone (2), and dictyochromenol (3), is reported here. The chemical structures of 1 and 2 were determined by spectral means (1D, 2D NMR, MS) and chemical data. Among these three, (2′E., 6′E.)-2-farnesyl-1,4-benzoquinone was the most active (MCF-7 GI50 = 1.8 µg/ml; H-460 GI50 = 4.8 µg/ml; SF-268 GI50 = 3.5 µg/ml).

Xanthine oxidase inhibitory activity of some Panamanian plants from Celastraceae and Lamiaceae

Thirty four crude extracts of Panamanian plants, from nine species of Celastraceae and Lamiaceae, were assayed for xanthine oxidase (XO) inhibitory activity. The enzymatic activity was estimated by measuring the increase in absorbance at 290 nm due to uric acid formation. Eighty five percent of the crude extracts were found to possess XO inhibitory activity at 50 micrograms/ml and all the extracts of the species from Lamiaceae were active even at 1 micrograms/ml. The ethanol extracts of Hyptis obtusiflora Presl ex Benth. (Lamiaceae) and H. lantanaefolia Poit. (Lamiaceae) exhibited the highest activity with an inhibition of approximately 40% at 1 micrograms/ml.

Screening of Latin American plants for antiparasitic activities against malaria, Chagas disease, and leishmaniasis.

In order to explore rationally the medical potential of the plant biodiversity of the Central and South American region as a source of novel antiparasitic molecules, a multinational Organization of American States (OAS) project, which included the participation of multidisciplinary research centers from Argentina, Bolivia, Colombia, Costa Rica, Guatemala, Nicaragua and Panama, was carried out during the period 2001-2004. This project aimed at screening organic plant extracts for antitrypanosomal, antileishmanial and antimalarial activities and subsequently isolating and characterizing bioactive molecules. Plants for antiparasitic screening were selected from a database of ethnomedical uses of Latin American plants (PlanMedia) based on the amount of biological and chemical information available in the literature. We report here the evaluation of 452 extracts from 311 plant species in vitro screens against Plasmodium falciparum, Leishmania mexicana, and Trypanosoma cruzi. Out of 311 species tested, 17 plants (5.4%) showed antiparasitic activities at IC50 values ≤ 10 µg/mL. The most active plants were Acnistus arborescens (L.) Schltdl. (Solanaceae) (leaf, EtOH, IC50: 4 µg/mL) Monochaetum myrtoideum Naudin (Melastomataceae) (leaf, MeOH, IC50: 5 µg/mL) and Bourreria huanita (Lex.) Hemsl. (Boraginaceae) (branch, EtOH, IC50: 6 µg/mL). These were selectively active against P. falciparum, L. mexicana and T. cruzi, respectively.

Inhibitory effects of Cordia spinescens extracts and their constituents on reverse transcriptase and protease from human immunodeficiency virus

By bioactive‐guided fractionation of a water extract of Cordia spinescens, magnesium lithospermate (1), calcium rosmarinate (2) and magnesium rosmarinate (3) were isolated as potent inhibitory substances against HIV‐1 reverse transcriptase (RT) with IC50 values of 0.8, 5.8 and 3.1 μM, respectively. However, they were weak HIV‐1 protease (PR) inhibitors with IC50>100 μM. The RT inhibition by these compounds was noncompetitive with respect to dTTP substrate.