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

Characteristic chromanone acids from Calophyllum membranaceum: Determination of C-3 configuration and anti-inflammatory activity

One undescribed homologous furanochromanone (1) featuring a 6/6/5/3 tetracyclic skeleton and four highly oxidized pyranochromanones (2-5), along with a set of four pyranochromanone stereoisomers [(±)-6a and (±)-6b], were isolated from the leaves of Calophyllum membranaceum Gardn. Et Champ. Their structures were elucidated by using spectroscopic data, Snatzke's method, quantum-chemical calculations, and X-ray crystallographic analysis. The correlation of characteristic Cotton effects and specific chemical shifts with C-3 configuration provided a convenient approach to assign the C-3 configuration of 2,3-dimethylchromanones. The stereochemical assignments of 3-OH substituted pyranochromanones by quantum-based NMR methods following single/double MTPA derivatization were consistent with the ECD/NMR prediction, which verified the feasibility and reliability of the proposed empirical rule. The underlying mechanism was further clarified by conformational and molecular orbital analyses. Moreover, biological evaluation and binding assays demonstrated that compound 3 (KD = 0.45 μM) tightly binds to the TLR4-MD2 target, thereby inhibiting the TLR4/MyD88-dependent and -independent signal pathways. This study provides the first evidence that Calophyllum chromanones are a novel structural type of TLR4 inhibitors, exerting their anti-inflammatory effects by disrupting the binding between TLR4 and MD2.

Xanthones: Biosynthesis and Trafficking in Plants, Fungi and Lichens

Xanthones are a class of secondary metabolites produced by plant organisms. They are characterized by a wide structural variety and numerous biological activities that make them valuable metabolites for use in the pharmaceutical field. This review shows the current knowledge of the xanthone biosynthetic pathway with a focus on the precursors and the enzymes involved, as well as on the cellular and organ localization of xanthones in plants. Xanthone biosynthesis in plants involves the shikimate and the acetate pathways which originate in plastids and endoplasmic reticulum, respectively. The pathway continues following three alternative routes, two phenylalanine-dependent and one phenylalanine-independent. All three routes lead to the biosynthesis of 2,3',4,6-tetrahydroxybenzophenone, which is the central intermediate. Unlike plants, the xanthone core in fungi and lichens is wholly derived from polyketide. Although organs and tissues synthesizing and accumulating xanthones are known in plants, no information is yet available on their subcellular and cellular localization in fungi and lichens. This review highlights the studies published to date on xanthone biosynthesis and trafficking in plant organisms, from which it emerges that the mechanisms underlying their synthesis need to be further investigated in order to exploit them for application purposes.

Plant Coumarins with Anti-HIV Activity: Isolation and Mechanisms of Action

This review summarizes and systematizes the literature on the anti-HIV activity of plant coumarins with emphasis on isolation and the mechanism of their antiviral action. This review summarizes the information on the anti-HIV properties of simple coumarins as well as annulated furano- and pyranocoumarins and shows that coumarins of plant origin can act by several mechanisms: inhibition of HIV reverse transcriptase and integrase, inhibition of cellular factors that regulate HIV-1 replication, and transmission of viral particles from infected macrophages to healthy ones. It is important to note that some pyranocoumarins are able to act through several mechanisms or bind to several sites, which ensures the resistance of these compounds to HIV mutations. Here we review the last two decades of research on the anti-HIV activity of naturally occurring coumarins.

Improving the Antioxidant Properties of Calophyllum inophyllum Seed Oil from French Polynesia: Development and Biological Applications of Resinous Ethanol-Soluble Extracts

Tamanu oil from Calophyllum inophyllum L. has long been used in traditional medicine. Ethanol extraction was found the best strategy for recovering bioactive compounds from the resin part of Tamanu oil, yielding two neutral and acidic resins fractions with high phenolics, flavonoids and pyranocoumarins concentrations. A further cascade of LPLC/HPLC separations of neutral and acidic resin fractions allowed identifying fifteen metabolites, and among them, calanolide D and 12-oxocalanolide A (both in neutral fraction) were first identified from a natural source. All these extracts, subfractions and isolated metabolites demonstrated increased free radical scavenging, antioxidant, anti-inflammatory, antimicrobial and antimycobacterial activity compared to Tamanu oil and its de-resinated lipid phase. Overall, these results could promote resinous ethanol-soluble Tamanu oil extracts as a useful multifaceted and renewable medicinal resource.

Naturally Occurring Calanolides: Occurrence, Biosynthesis, and Pharmacological Properties Including Therapeutic Potential

Calanolides are tetracyclic 4-substituted dipyranocoumarins. Calanolide A, isolated from the leaves and twigs of Calophyllum lanigerum var. austrocoriaceum (Whitmore) P. F. Stevens, is the first member of this group of compounds with anti-HIV-1 activity mediated by reverse transcriptase inhibition. Calanolides are classified pharmacologically as non-nucleoside reverse transcriptase inhibitors (NNRTI). There are at least 15 naturally occurring calanolides distributed mainly within the genus Calophyllum, but some of them are also present in the genus Clausena. Besides significant anti-HIV properties, which have been exploited towards potential development of new NNRTIs for anti-HIV therapy, calanolides have also been found to possess anticancer, antimicrobial and antiparasitic potential. This review article provides a comprehensive update on all aspects of naturally occurring calanolides, including their chemistry, natural occurrence, biosynthesis, pharmacological and toxicological aspects including mechanism of action and structure activity relationships, pharmacokinetics, therapeutic potentials and available patents.

The Genus Calophyllum: Review of Ethnomedicinal Uses, Phytochemistry and Pharmacology

The species of genus Calophyllum have been reported for several ethnomedicinal uses in the traditional systems of medicine. The scientific study of the genus Calophyllum revealed that it is a rich source of bioactive secondary metabolites. These phytochemicals have shown a wide range of biological activities. Some of these have reached to the clinical developmental stage. The Calophyllum inophyllum seed oil has been proved to be an acceptable sustainable source of biodiesel. Few species of the genus are endangered and have been included in the red list of threatened species by the IUCN Red List. Owing to the importance of the genus a review of its ethnomedicinal uses, phytochemistry, and pharmacology has been carried out. It will further help to explore the molecular mechanism of phytochemicals for health benefits.

Xanthones and Cancer: from Natural Sources to Mechanisms of Action

Xanthones are a class of heterocyclic natural products that have been widely studied for their pharmacological potential. In fact, they have been serving as scaffolds for the design of derivatives focusing on drug development. One of the main study targets of xanthones is their anticancer activity. Several compounds belonging to this class have already demonstrated cytotoxic and antitumor effects, making it a promising group for further exploration. This review therefore focuses on recently published studies, emphasizing their natural and synthetic sources and describing the main mechanisms of action responsible for the anticancer effect of promising xanthones.

Molecular Characterization and Bioactivity of Coumarin Derivatives from the Fruits of Cucumis bisexualis

Cucumis bisexualis (Cucurbitaceae) is known as "mapao egg" or "muskmelon egg", which has been widely used as a wild melon in Chinese folk. Nine new coumarin derivatives (1-9), named 7-hydroxy-3-(4',6'-dihydroxy-5'-isopropyl-3″,3″-dimethyl-2 H-chromen)-6-prenyl-2 H-chro-men-2-one (1), 7-hydroxy-3-(5'-prenyl-3″,3″-dimethyl-2 H-chromen)-6-prenyl-2 H-chromen-2-one (2), 3-(6'-hydroxy-5'-prenyl-3″,3″-dimethyl-2 H-chromen)-6-prenyl-2 H-chromen-2-one (3), 3-(5'-ethyl-3″,3″-dimethyl-2 H-chromen)-6-prenyl-2 H-chromen-2-one (4), 3-(4',6'-dihydroxy-5'-dimeth-ylallyl-3″,3″-dimethyl-2 H-chromen)-6-prenyl-2 H-chromen-2-one (5), 3-[4',6'-dihydroxy-5'-(2-pro-penyl)-3″,3″-dimethyl-2 H-chromen]-14,15-dimethyl-pyrano-chromen-2-one (6), 3-(6'-dihydroxy-5'-isopropanol-3″,3″-dimethyl-2 H-chromen)-14,15-dimethyl-pyrano-chromen-2-one (7), 3-(5'-iso-pentenol-3″,3″-dimethyl-2 H-chromen)-14,15-dimethyl-pyrano-chromen-2-one (8), 3-(4',6'-dihydr-oxy-5'-prenyl-3″,3″-dimethyl-2 H-chromen)-14,15-dimethyl-pyrano-chromen-2-one (9), together with 12 known compounds (10-21), were isolated and identified by spectroscopic analysis and references from the active site (EtOAc soluble fraction) of the fruits of C. bisexualis for the first time. Compounds (1-21) were evaluated for antiacetylcholinesterase (AChE) and hepatoprotective activities for the first time. Compounds 1, 3, 5, 6, 7, and 9 showed anti-AChE activities with IC₅₀ values ranging from 11.23 to 89.69 μM, and compounds 2, 4, 12, 15, 17, 18, and 19 (10 μM) exhibited moderate hepatoprotective activities. These findings shed much light on a better understanding of the anti-AChE and hepatoprotective effects of these coumarin derivatives and provided new insights into developing better anti-AChE and hepatoprotective drugs in the future.

Cancer Chemopreventive Activity of Xanthones from Calophyllum elatum

In our continuing search for compounds with antitumor-promoting activity, we screened eight xanthones isolated from Calophyllum elatum Bedd. (Guttiferae) by examining their possible inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12- O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells. Several compounds tested in this study showed inhibitory activity against EBV, without showing any cytotoxicity. Isogarciniaxanthone E (2) showed more potent activity than any of the other compounds tested. Furthermore, isogarciniaxanthone E (2) exhibited a marked inhibitory effect on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test.

Potential Secondary Metabolites from Marine SpongeAaptos aaptosfor Atherosclerosis and Vibriosis Treatments

Natural products play a crucial role in drug discovery. In the last decade, the advent of marine natural product research has produced a remarkable number of compounds, particularly those isolated from marine sponges, with a broad range of activities for the treatment of human and animal diseases. In this study, five known alkaloids namely aaptamine (1), 9-demethylaaptamine (2), 4- N-methylaaptamine (3), 9-methoxyaaptamine (4), 9-demethyloxyaaptamine (5), an uncommon amide in sponge, 4-hydroxybenzamide (6) and 3 β,5α-cholesterol (7) were isolated from the butanol extract of Aaptos aaptos (Schmidt, 1864) by bioactivity-guided isolation. Their structures were determined based on a detailed analysis of their 1D and 2D spectroscopic NMR and EIMS spectral data as well as comparison with literature data. Cytotoxic activity and anti-atherosclerotic property of the compounds were determined based on their ability to increase the transcriptional activity of SRB1 promoter and PPRE in human liver HepG2 cell line. The results showed that compounds 4 and 7 exhibited cytotoxic effects and compounds 1–4 and 7 increased the transcriptional activity of SRB1 promoter and PPRE. This suggests that compounds isolated from A. aaptos may have potential as anti-cancer agents and to reduce the progression of atherosclerosis. In addition, the compounds 1–4 displayed antibacterial activity against shrimp pathogenic bacteria, Vibrio harveyi and Vibrio sp. This suggests that the compounds have potential as vibriosis treatment.

BF3·Et2O Catalysed 4-Aryl-3-phenyl-benzopyrones, Pro-SERMs, and Their Characterization

We have synthesized the novel 4-(4-hydroxy-benzyl)-3-phenyl-chromen-2-one which is a precursor of SERMs with a smaller number of steps and good yield. Two methodologies for the synthesis have been worked out. Anhydrous BF3·Et2O catalyzed reaction was found to be selective for product formation while anhydrous AlCl3, FeCl3, and SnCl4 catalyzed ones were nonselective.

Evaluation of toxicity of Calophyllum brasiliense stem bark extract by in vivo and in vitro assays

ETHNOPHARMACOLOGICAL RELEVANCE

Calophyllum brasiliense Camb., Clusiaceae, is commonly known as "guanandi" and its stem bark is used in Brazilian traditional medicine to treat rheumatism, vein problems, hemorrhoids and gastric ulcers. The aim of this study was to evaluate the toxicity of hexane extract of Calophyllum brasiliense stem bark (HECb) using in vitro and in vivo experimental models.

MATERIALS AND METHODS

In vitro toxicity was evaluated by Alamar Blue cytotoxicity assay and micronucleus test, using Chinese hamster ovary (CHO-k1) epithelial cells. in vivo toxicity was evaluated by oral acute and subchronic toxicity assays. In the oral acute toxicity screening, a single dose of HECb was administered to mice at doses ranging from 250 to 1000 mg/kg. In the subchronic study, HECb was administered orally for 30 days to Wistar rats at doses of 100 mg/kg and 500 mg/kg. Phytochemical analyses were performed by HPLC/UV-vis, secondary metabolites were quantified by spectrophotometric methods.

RESULTS

HECb presented IC50=119.94±4.31 µg/mL after a 24 h cytotoxicity test using CHO-k1 cells, showing low cytotoxicity. However, when the cells were exposed to HECb for 72 h, the IC50 value was 8.39±2.00 µg/mL, showing in this case, a pronounced cytotoxic effect. In the oral acute toxicity studies, doses up to 500 mg/kg of HECb did not cause any changes in both male and female mice. At 1000 mg/kg, male mice showed signs typical of depression and stimulation that were reversed at 72 h. Besides, female mice were more sensitive to the toxic effect of HECb at 1000 mg/kg, which initially presented typical agitation signals, followed by depression signals, leading to death of all the animals at 24h. In subchronic assay with rats, HECb administered orally at doses of 100 and 500 mg/kg did not cause significant changes in all clinical parameters evaluated. Histopathological analyses showed no deleterious effect in the vital organs of rats. Preliminary phytochemical analysis revealed the presence of phenolic compounds, steroids, and volatile coumarins. Analysis by HPLC showed two major peaks characteristic of chromanones.

CONCLUSIONS

In vitro toxicological tests showed that HECb exhibited cytotoxicity especially after 72 h of exposition, and mutagenicity on the highest tested dose. The in vivo studies demonstrated that HECb produced some toxicity signs at the highest dose tested, particularly, in the acute toxicity test but showed no significant signs of toxicity in the subchronic assay. Based on these and previous pharmacological studies, it is possible to say that HECb did not exhibit significant toxicity at its effective dose. This suggests that HECb is relatively safe in humans at its effective dose.

Design, synthesis and experimental validation of novel potential chemopreventive agents using random forest and support vector machine binary classifiers

Compared to the current knowledge on cancer chemotherapeutic agents, only limited information is available on the ability of organic compounds, such as drugs and/or natural products, to prevent or delay the onset of cancer. In order to evaluate chemical chemopreventive potentials and design novel chemopreventive agents with low to no toxicity, we developed predictive computational models for chemopreventive agents in this study. First, we curated a database containing over 400 organic compounds with known chemoprevention activities. Based on this database, various random forest and support vector machine binary classifiers were developed. All of the resulting models were validated by cross validation procedures. Then, the validated models were applied to virtually screen a chemical library containing around 23,000 natural products and derivatives. We selected a list of 148 novel chemopreventive compounds based on the consensus prediction of all validated models. We further analyzed the predicted active compounds by their ease of organic synthesis. Finally, 18 compounds were synthesized and experimentally validated for their chemopreventive activity. The experimental validation results paralleled the cross validation results, demonstrating the utility of the developed models. The predictive models developed in this study can be applied to virtually screen other chemical libraries to identify novel lead compounds for the chemoprevention of cancers.

Comparing conventional and supercritical extraction of (-)-mammea A/BB and the antioxidant activity of Calophyllum brasiliense extracts

Calophyllum brasiliense is a rich source of bioactive coumarins, xanthones and biflavonoids. The aim of the study was to compare the phenol contents and the antioxidant activity of C. brasiliense extracts obtained by conventional and supercritical fluid extraction (SFE) methods, as well as the quantification of crude extracts and (-)-mammea A/BB yields. Dichloromethane and hexane were used as solvents for the conventional extractions and SFE was developed using supercritical CO₂; the kinetic curves were modeled using a second-order empirical model. The dichloromethane extract presented the best total yield, although it showed the lowest content of (-)-mammea A/BB. The concentration of the coumarin was considerably higher in extracts obtained by the supercritical fluid method and a higher antioxidant activity was assigned to extracts obtained by this technique. Concerning the total phenolic contents, both the dichloro-methane and the supercritical extractions produced satisfactory amounts. The SFE method proved to be more promising than conventional methods.

A fast and efficient HPLC-PDA-MS method for detection and identification of pyranochromanone acids in Calophyllum species

Pyranochromanone acids isolated from Calophyllum species have shown a variety of biological potentialities including antioxidant, antiulcer, anticancer and anti-Helicobacter pylori activities. These compounds seem to be the main constituents of Cuban Calophyllum species together xanthones and biflavonoids. Recently, the pyranochromanone acids calophyllic acid, isocalophyllic acid, apetalic acid, calolongic acid, isoapetalic acid, pinetoric acid I, pinetoric acid II, were isolated from Calophyllum pinetorum, a Cuban endemic species. The objective of the present work was the development of a rapid and efficient HPLC-DAD-MS method for fast screening of pyranochromanones in the leaves and resins of different endemic Calophyllum spp of Cuba, without clean-up procedures. For this purpose, a generalized fragmentation pathway was proposed and used to characterize, by HPLC-DAD-MS, the pyranochromanone acids in leaves and resins of different Calophyllum species. The developed method enables to detect also minor compounds in Calophyllum spp. The structures proposed by MS data for these compounds were unambiguous confirmed by 1D and 2D-NMR analysis and three new pyranochromanone acids, isocalolongic acid, pinetoric acid III and isopinetoric acid III, were reported here for the first time.

Palladium-catalyzed, pyrrolidine-mediated arylmethylation of ketones and aldehydes with coumarinyl(methyl) acetates

We report the palladium-catalyzed, pyrrolidine-mediated α-benzylation of enamines generated from aldehydes and ketones. The method allows for direct coupling of medicinally relevant coumarin moieties with aldehydes and ketones in good yield under mild conditions. The reaction is believed to proceed via a Pd-π-benzyl complex generated from (coumarinyl)methyl acetates.

Effects of (-) mammea A/BB isolated from Calophyllum brasiliense leaves and derivatives on mitochondrial membrane of Leishmania amazonensis

We have previously demonstrated antileishmanial activity on Leishmania amazonensis of the natural (1-2), synthetic (7) and derivatives of coumarin (-) mammea A/BB (3-6) isolated from the dichloromethane extract of Calophyllum brasiliense leaves. The aim of the present study was to evaluate morphological and ultrastructural alterations in Leishmania amazonensis induced by these compounds. In promastigote forms, all seven compounds produced significant morphological and ultrastructural alterations, as revealed by scanning and transmission electron microscopy. The compound 5,7-dihydroxy-8-(2-methylbutanoyl)-6-(3-methylbutyl)-4-phenyl-chroman-2-one (3), the most active antileishmanial with LD₅₀ of 0.9 μM), induced cell shrinkage and a rounded appearance of the cells. Parasites incubated in the presence of compound (3) showed ultrastructural changes, such as the appearance of mitochondrial swelling with a reduction in the density of the mitochondrial matrix and the presence of vesicles inside the mitochondrion, indicating damage and significant change in this organelle; abnormal chromatin condensation, alterations in the nuclear envelope, intense atypical cytoplasmic vacuolization, and the appearance of autophagic vacuoles were also observed. In addition, the compound (3) may be acting to depolarize the mitochondrial membrane potential of the cells, leading to death of the parasite.

Soulamarin, a new coumarin from stem bark of Calophyllum soulattri

The extracts of the stem bark of Calophyllum soulattri gave a new pyranocoumarin, soulamarin (1), together with five other xanthones caloxanthone B (2), caloxanthone C (3), macluraxanthone (4), trapezifolixanthone (5) and brasixanthone B (6) one common triterpene, friedelin (7), and the steroidal triterpene stigmasterol (8). The structures of these compounds were established based on spectral evidence (1D and 2D NMR).

A new biphenyl and antimicrobial activity of extracts and compounds from Clusia burlemarxii

Phytochemical investigation on Clusia burlemarxii (Clusiaceae) led to isolation and identification of nine compounds. Were isolated from leaves 3-O-α-L- rhamnopyranosylquercetin, 3-O-α-L-rhamnopyranosylkaempferol, 4-hydroxy-5,5-dimethyldihydrofuran-2-one, 2Z-δ-tocotrienoloic acid and friedelin and were isolated from trunk betulinic acid, protocatechuic acid, lyoniresinol, and a new biphenyl 2,2-dimethyl-3,5-dihydroxy-7-(4-hydroxyphenyl)chromane. The structures were determined by ¹H, ¹³C-NMR, DEPT, HMBC, HMQC, HRESIMS. The Minimal Inhibitory Concentration against Streptococcus mutans, Staphylococcus aureus, Bacillus subtilis, Micrococcus luteus, Escherichia coli, Salmonella choleraesuis, Pseudomonas aeruginosa, Aspergillus niger and Cladosporium cladosporioides was also determined. Extracts and compounds showed significant activity against tested Gram-positive bacteria, none activity against tested Gram-negative bacteria and fungi.

Inhibition of HIV-1 reverse transcriptase, toxicological and chemical profile of Calophyllum brasiliense extracts from Chiapas, Mexico

Calophyllum species are sources of calanolides, which inhibit human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT). The hexane extract of the leaves from C. brasiliense collected in Soconusco, State of Chiapas, Mexico, analyzed by HPLC showed to contain apetalic acid, calanolides B, and C. It showed potent anti-HIV-1 RT inhibition (IC(50)=20.2 μg/ml), but was not toxic in mice (LD(50)=1.99 g/kg). The histological study of the mice treated at the highest dose revealed no alteration on hepatocytes, and an increase in the number of spleen megakaryocytes. These results suggest this extract is suitable to continue studies for developing a phytodrug against HIV-1.

Two new 4-arylcoumarins from the seeds of Calophyllum polyanthum

Two new 4-arylcoumarins, 7,4'-dihydroxy-6,8-dimethoxy-4-phenylcoumarin (1) and 7-hydroxy-6,8,4'-trimethoxy-4-phenylcoumarin (2), together with four known compounds were isolated from the seeds of Calophyllum polyanthum. The structures of the new compounds were determined by extensive spectroscopic analyses, and the structure of compound 2 was confirmed by X-ray crystallography analysis. Both new compounds exhibited significant cell protective activities against H(2)O(2)-induced human umbilical vein endothelial cell damage.

Evaluation of the proliferative activity of methanol extracts from six medicinal plants in murine spleen cells

A number of natural compounds have been used as immunomodulatory agents, enabling the function of the immune system to be modified by stimulating or suppressing it. There has been increasing interest in the study of therapeutic action of plant extracts regarding their immunomodulatory activity. The aim of this study was to identify and evaluate the action of extracts of the medicinal plants Calophyllum brasiliense, Ipomoea pes-caprae, Matayba elaeagnoides, Maytenus robusta, Rubus imperialis and Vernonia scorpioides on the development of spleen cells from mice, using the in vitro cellular proliferation assay. The cells, obtained by mechanical rupture of mice spleen (5x10(4) cells/mL), were incubated with methanol extracts (10, 50, 100 and 200 µg/mL) and phytohemagglutinin (PHA, 5 µg/mL). The basal control for proliferation consisted of cells alone, while the positive control consisted of cells and PHA. The cell culture was kept at 37 ºC in 5% CO2 for 72 hours, and cell proliferation was revealed by the blue tetrazolium reduction assay (MTT). The results were expressed as percentage of growth and were analyzed using the Kruskal-Wallis and Mann-Whitney tests. The C. brasiliense, I. pes-caprae and M. elaeagnoides extracts showed dose-dependent induction of cell proliferation, with a significant increase in cell proliferation (p<0.03) and percentage growth of 88.2%, 73.1% and 52.7%, respectively, suggesting T lymphocyte stimulation. By contrast, M. robusta, R. imperialis and V. scorpioides extracts showed significance only with a negative percentage of growth, suggesting inhibition of cell proliferation (p<0.04). Further biomonitoring studies will enable the fractions and isolated substances responsible for the immunomodulatory activities to be identified.

Efficacy of components from leaves of Calophyllum brasiliense against Leishmania (Leishmania) amazonensis

Leishmanicide potential of Calophyllum brasiliense leaves on promastigote and amastigote of Leishmania (Leishmania) amazonensis is evaluated. The LD(50) of dichloromethane extract and hexane fraction for promastigotes was respectively 40 microg/ml and 20 microg/ml. In mouse peritoneal macrophages infected with Leishmania amastigotes the Infection Index decreased respectively 100% and 84.2% in 80 microg/ml and 40 microg/ml concentrations of dichloromethane extract. Hexane fraction decreased infection index respectively by 98.7% and 91.3% within the same concentrations. It was found that pretreatment with dichloromethane extract or with hexane fraction of experimentally infected BALB/c mice decrease the volume of the lesions by L. (L.) amazonensis. Moreover, animals treated topically also revealed healing lesions. Besides, the parasite load in the animals' popliteal lymph nodes was significantly reduced in treated animals, showing that plant components actually control infection. Results show that crude extract and hexane fraction of C. brasiliense reveal a significant in vitro and in vivo leishmanicide activity.

Apoptosis inducing activity of 4-substituted coumarins from Calophyllum brasiliense in human leukaemia HL-60 cells

With the objective of identifying anti-tumour-promoting agents, we carried out a primary screening of ten 4-substituted coumarins isolated from Calophyllum brasiliense Camb. (Guttiferae), to determine the ability of these compounds to inhibit proliferation of the human leukaemia cell line HL-60. Among the 4-substituted coumarins isolated, calophyllolide (2) and mammea B/BB (3) showed significant cytotoxicity against HL-60 cells. Fluorescence microscopy with Hoechst 33342 staining revealed that the percentage of apoptotic cells with fragmented nuclei and condensed chromatin increased in a time-dependent manner after treatment with calophyllolide (2) or mammea B/BB (3). In addition, the activity of caspase-9 and caspase-3 was also enhanced in a time-dependent manner upon treatment with the 4-substituted coumarins 2 and 3. Caspase-9 and caspase-3 inhibitors suppressed apoptosis induced by 4-substituted coumarins 2 and 3. These results suggest that calophyllolide (2) and mammea B/BB (3) induced apoptosis in HL-60 cells through activation of the caspase-9/caspase-3 pathway, which is triggered by mitochondrial dysfunction.

Antiproliferative, cytotoxic and antitumour activity of coumarins isolated from Calophyllum brasiliense

Among the eight Calophyllum species found on the American continent, Calophyllum brasiliense is the most widely distributed. Chemical analysis of this species has shown the presence of xanthones with cancer chemopreventive properties and antifungal activity. Recently, three new coumarins with antineoplastic properties have been found. In this study, we have evaluated the biological effects of the antiproliferative activity of coumarins isolated from C. brasiliense on the survival, cell cycle and apoptosis of cells in-vitro and their antitumour effects in mice. The cytological study showed that coumarins from C. brasiliense reduce the survival of BMK cells (baby mouse kidney cells) by inducing apoptosis and, to a lesser degree, necrosis. The cell cycle was arrested in S-phase and the division of BMK cells was inhibited. Coumarins had caused a reduction of experimental tumours in 83% of animals by the end of the treatment. Therefore, coumarins have the potential to be used alone or in combination with other antineoplastic drugs, and they might increase the effectiveness of other treatments for cancer.

Chemical and pharmacological aspects of the genus Calophyllum

The Calophyllum genus (Clusiaceae) is composed of ca. 200 species, with a pantropical distribution. Some species are used as medicinal agents to treat a large number of diseases, including gastric ulcers, infections, pain, tumors, and inflammatory processes, among others. A review of the literature regarding the chemical and biological aspects of these plants indicates cytotoxic activity against several cell lines, inhibition of HIV-1 reverse transcriptase, antisecretory and cytoprotective properties, antinociceptive, molluscicidal and antimicrobial effects, etc., related particularly to the presence of coumarins, xanthones, flavonoids, and triterpenes. This review, therefore, deals with the chemistry, and pharmacology or biology of the main plants belonging to the genus Calophyllum, with particular emphasis on C. brasiliense, studied by our research group.

Constituents of the Cuban endemic species Calophyllum pinetorum

A new prenylated xanthone, pinetoxanthone (1), and two new pyranochromanones, pinetoric acid I (2) and pinetoric acid II (3), together with 10 known compounds, namely, the triterpenes friedelin and canophyllol, the xanthone macluraxanthone, the pyranochromanone derivatives calophyllic acid, isocalophyllic acid, calolongic acid, apetalic acid, and isoapetalic acid, and the flavonoids amentoflavone and apigenin, were isolated from the stem bark and leaves of Calophyllum pinetorum, an endemic species in Cuba. The structures of 1-3 were elucidated by spectroscopic methods including 1D and 2D NMR experiments as well as HRESIMS analysis.