Chemical constituents of Calophyllum brasiliense. 2. Structure of three new coumarins and cancer chemopreventive activity of 4-substituted coumarins

Angiotensin-converting enzyme inhibition by Brazilian plants

The potential antihypertensive activity of Brazilian plants was evaluated in vitro by its ability to inhibit the angiotensin-converting enzyme (ACE). Forty-four plants belonging to 30 families were investigated. Plants were selected based on their popular use as antihypertensive and/or diuretics. The following plants presented significant ACE inhibition rates: Calophyllum brasiliense, Combretum fruticosum, Leea rubra, Phoenix roebelinii and Terminalia catappa.

Antileishmanial activity of crude extract and coumarin from Calophyllum brasiliense leaves against Leishmania amazonensis

Infections by protozoans of the genus Leishmania are a major worldwide health problem, with high endemicity in developing countries. The drugs of choice for the treatment of leishmaniasis are the pentavalent antimonials, which show renal and cardiac toxicity. As part of a search for new drugs against leishmaniasis, we evaluated the in vitro leishmanicidal activity of the (-) mammea A/BB. The compound (-) mammea A/BB is a coumarin-type mammea purified from a dichloromethane crude extract of leaves of Calophyllum brasiliense Cambess (Clusiaceae). The isolated compound was characterized using spectral analyses by UV, infrared, nuclear magnetic resonance of (1)H, (13)C, distortionless enhancement by polarization transfer, correlation spectroscopy, heteronuclear multiple bond correlation, and heteronuclear multiple quantum coherence. The compound (-) mammea A/BB showed significant activity against promastigote and amastigote forms of L. amazonensis, with IC(50) (50% inhibition concentration of cell growth) at a concentration of 3.0 and 0.88 mug/ml and IC(90) (90% inhibition concentration of cell growth) of 5.0 and 2.3 microg/ml, respectively. The coumarin (-) mammea A/BB showed no cytotoxicity against J774G8 macrophages in culture, when it was tested at high concentrations that inhibited promastigote forms. Electron microscopy studies revealed considerable ultrastructural changes when promastigote forms of L. amazonensis were treated with 3.0 microg/ml of the coumarin (-) mammea A/BB for 72 h. We observed significant changes such as mitochondrial swelling with concentric membranes in the mitochondrial matrix and intense exocytic activity in the region of the flagellar pocket. Other alterations included the appearance of binucleate cells and multiple cytoplasmic vacuolization. These results showed that (-) mammea A/BB is a potent growth inhibitor of L. amazonensis and caused important changes in the parasite's ultrastructure. This study provided new perspectives on the development of novel drugs with leishmanicidal activity obtained from natural products.

Cascade Synthesis of Polyoxygenated 6H,11H-[2]Benzopyrano-[4,3-c][1]benzopyran-11-ones

2-(methoxymethoxymethyl)aryllead triacetates, obtained in situ from the corresponding arylboronic acids, reacted with 4-hydroxycoumarins, leading to 3-(2-methoxymethoxymethyl)aryl-4-hydroxycoumarin derivatives in good to high yields. These compounds underwent a cascade sequence of reactions, deprotection-halogenation-annulation, to afford polyoxygenated tetracyclic 6H,11H-[2]benzopyrano-[4,3-c] [1]benzopyran-11-ones in good yields. Some compounds showed a moderate cytotoxicity against human epithelial mammary HBL100 cells.

Composition of fatty acids triacylglycerols and unsaponifiable matter in Calophyllum calaba L. oil from Guadeloupe

The composition of the kernel oils of two Calophyllum species (Calophyllum calaba L. and Calophyllum inophyllum L.) was investigated. The physico-chemical properties and fatty acid composition of the kernel oils were examined. In two species, oleic acid C18:1 (39.1-50%) is the dominating fatty acid followed by linoleic acid C18:2 (21.7-31.1%) as the second major fatty acid. Stearic C18:0 (13.4-14.3%) and palmitic C16:0 (11-13.7%) acids are the major saturates. The oils contains an appreciable amount of unsaturated fatty acids (70.8-73.10%). Most of the fatty acids are present as triacylglycerol (76.7-84%), twenty one triacylglycerols are detected with predominantly unsaturated triacylglycerols. The total unsaponifiable content, its general composition and the identity of the components of the sterol and tocopherol fractions are presented. In both species, analysis of the unsaponifiable fractions revealed the preponderance of phytosterols, mainly stigmasterol (35.8-45.1%) and beta-sitosterol (41.1-43.1%). Among the eight tocopherols and tocotrienols present in two species, variations exist; alpha-tocopherol (183 mg/kg) is the main tocopherol in Calophyllum calaba L. and Delta-tocotrienol (236 mg/kg) is the dominant tocotrienol in Calophyllum inophyllum L.

Inhibition of leukemic cell growth by a novel anti-cancer drug (GUT-70) from calophyllum brasiliense that acts by induction of apoptosis

During our search for cancer chemopreventing compounds derived from plant sources, we discovered that the natural product GUT-70, isolated from the stem bark of Calophyllum brasiliense collected in Brazil, significantly inhibits the growth of leukemic cells. GUT-70, characterized as a tricyclic coumarin, 5-methoxy-2,2-dimethyl-6-(2-methyl-1-oxo-2-butenyl) -10-propyl-2H,8H-benzo[1,2-b;3,4-b']dipyran-8-one (C(23)H(26)O(5)), inhibited all 6 human leukemic cell lines evaluated, including the P-glycoprotein overexpressing cell line, in a concentration and time-dependent manner with IC(50) values from 2-5 microM. Furthermore, GUT-70 did not inhibit colony formation by normal hematopoietic progenitors up to 30 microM and also did not inhibit the proliferation of normal human hepatocytes up to 30 microM. GUT-70 activated the caspase 2, 3, 8 and 9, and induced the apoptosis in leukemic cells, which was inhibited by caspase inhibitors. GUT-70 induced anti-leukemic effects independent of the p53-p2l(WAFl/CIP1) pathway and increased the overall expression of p27(KIP1) and p57(KIP2), to stop the cell cycle at the G(1)/S transition. Thus, a novel anti-cancer drug, GUT-70 isolated from the stem bark of C. brasiliense induces caspase-mediated and p53-independent apoptosis to overcome multidrug resistance and may become a potent leukemia therapeutics.

Antimicrobial and cytotoxic agents from Calophyllum inophyllum

The study of the chemical constituents of the root bark and the nut of Calophyllum inophyllum has resulted in the isolation and characterization of a xanthone derivative, named inoxanthone, 3, together with 12 known compounds: caloxanthones A, 4 and B, 5, macluraxanthone, 6, 1,5-dihydroxyxanthone, 7, calophynic acid, 8, brasiliensic acid, 9 inophylloidic acid, 10, friedelan-3-one, 11, calaustralin, 12, calophyllolide, 13, inophyllums C, 14 and E, 15. Their structures were established on the basis of spectral evidence. Their in vitro cytotoxicity against the KB cell line and their antibacterial activity and potency against a wide range of micro organisms were evaluated.

HIV-1 Inhibitory Compounds from Calophyllum brasiliense Leaves

The hexane, acetone and methanol extracts of Calophyllum brasiliense leaves were fractionated following a three bioassay guide: high HIV-1 RT inhibition, low cytotoxicity on MT2 cells and high inhibition of HIV-1 IIIb/LAV replication. This led to the isolation of three anti HIV-1 dipyranocoumarins: calanolides A and B and soulattrolide. In contrast, other isolated compounds such as apetalic acid, isoapetalic acid, a structural isomer of isoapetalic acid, friedelin, canophyllol and amentoflavone were devoid of HIV-1 RT inhibitory activity. Calanolide C was also obtained as a natural product and showed moderate inhibitory properties.