Anti-HIV coumarins from Calophyllum seed oil

Synthesis of new coumarin 3-(N-aryl) sulfonamides and their anticancer activity

Synthesis of coumarin 3-(N-aryl) sulfonamides was accomplished either by Knoevenagel condensation of anilinosulfonylacetic acids with suitable salicylaldehydes or by the reaction of methyl anilinosulfonylacetates with substituted salicylaldehydes in presence of a catalytic amount of a base. All the compounds tested for antiproliferative activity in different cancer cell lines have shown GI(50) values less than 100 microM.

HIV-1 Inhibition by Extracts of Clusiaceae Species from Mexico

The organic plant extracts of 21 species of Clusiaceae from Mexico were screened for anti HIV-1 reverse transcriptase activity in a non-radioactive immuno colorimetric assay. The extracts of 5 species (23.8%) exhibited significant inhibition (> or =70%) of HIV-1 RT activity; of these, only 4 extracts showed reduced toxicity to human lymphocytic MT2 cells and were further tested as inhibitors of HIV-1 IIIb/LAV replication in a cellular system. The best extracts were Calophyllum brasiliense (hexane) and Clusia quadrangula (CH(2)Cl(2)-MeOH) which inhibited HIV-1 RT (IC(50)=29.6 microg/ml and 42 microg/ml), and showed an EC(50)=92.5 microg/ml and 91 microg/ml, respectively, on MT2 cells. However, only Calophyllum brasiliense hexane extract showed significant inhibition on viral replication (ED(50)=37.1 microg/ml), while Clusia quadrangula was less active (ED(50)=124 microg/ml). These results support the idea that plant extracts represent a valuable source of potential anti HIV compounds.

Chromanones and Dihydrocoumarins from Calophyllum blancoi

Chromatographic fractionation of the acetone extract of the seeds of Calophyllum blancoi yielded six pyranochromanone derivatives; apetalic acid (1), isoapetalic acid (2), apetalic acid methyl ester (3), apetalic acid 5-O-acetate (4), isoapetalic methyl ester (5), and isoapetalic acid 5-O-acetate (6). In addition, one new dihydrocoumarin derivative, isorecedensolide (7), was also isolated together with recedensolide (8). The structures of the isolated compounds were established through analysis of NMR spectral data including 2D techniques as well as other physical and spectroscopic methods. Compounds 3, 4, 5, 7, and 8 showed mild activity against KB (human oral epidermoid carcinoma) and Hela (human cervical epitheloid carcinoma) tumor cell lines.

Novel antiviral agents: a medicinal plant perspective

Several hundred plant and herb species that have potential as novel antiviral agents have been studied, with surprisingly little overlap. A wide variety of active phytochemicals, including the flavonoids, terpenoids, lignans, sulphides, polyphenolics, coumarins, saponins, furyl compounds, alkaloids, polyines, thiophenes, proteins and peptides have been identified. Some volatile essential oils of commonly used culinary herbs, spices and herbal teas have also exhibited a high level of antiviral activity. However, given the few classes of compounds investigated, most of the pharmacopoeia of compounds in medicinal plants with antiviral activity is still not known. Several of these phytochemicals have complementary and overlapping mechanisms of action, including antiviral effects by either inhibiting the formation of viral DNA or RNA or inhibiting the activity of viral reproduction. Assay methods to determine antiviral activity include multiple-arm trials, randomized crossover studies, and more compromised designs such as nonrandomized crossovers and pre- and post-treatment analyses. Methods are needed to link antiviral efficacy/potency- and laboratory-based research. Nevertheless, the relative success achieved recently using medicinal plant/herb extracts of various species that are capable of acting therapeutically in various viral infections has raised optimism about the future of phyto-antiviral agents. As this review illustrates, there are innumerable potentially useful medicinal plants and herbs waiting to be evaluated and exploited for therapeutic applications against genetically and functionally diverse viruses families such as Retroviridae, Hepadnaviridae and Herpesviridae

Recent progress in the development of coumarin derivatives as potent anti-HIV agents

Numerous plant-derived compounds have been evaluated for inhibitory effects against HIV replication, and some coumarins have been found to inhibit different stages in the HIV replication cycle. This review article describes recent progress in the discovery, structure modification, and structure-activity relationship studies of potent anti-HIV coumarin derivatives. A dicamphanoyl-khellactone (DCK) analog, which was discovered and developed in our laboratory, and calanolide A are currently in preclinical studies and clinical trials, respectively.

Chemical constituents of Calophyllum brasiliensis: structure elucidation of seven new xanthones and their cancer chemopreventive activity

The first study of chemical constituents of the stem bark of Calophyllum brasilienses collected in Brazil has led to the isolation and identification of seven new xanthones named brasixanthones A (1), B (4), C (5), D (6), E (2), F (3), and G (10), together with 10 known xanthones. Among the xanthones isolated in this study, 4, 5, 6, and 11 were found to exhibit significant inhibitory activity against 12-O-tetradecanoylphorbol-13-acetate induced Epstein-Barr virus early antigen activation in Raji cells.

Novel cytotoxic 4-phenylfuranocoumarins from Calophyllum dispar

Eight new 4-phenylfuranocoumarins (1-8) have been isolated from the stem bark and the fruits of Calophyllum dispar, together with three known coumarins. The structures of 1-8 were established by means of spectroscopic analysis, including extensive 2D NMR studies. Some of these furanocoumarins exhibited significant cytotoxic activity against KB cells.

Plant-derived and semi-synthetic calanolide compounds with in vitro activity against both human immunodeficiency virus type 1 and human cytomegalovirus

Plant-derived and semi-synthetic calanolide compounds with anti-human immunodeficiency virus type 1 (HIV-1) activity were tested for anti-human cytomegalovirus (HCMV) activity in both cytopathic effect inhibition and plaque reduction assays. The results indicated that the anti-HCMV activity of calanolide compounds does not correlate with their activity against HIV-1. The semi-synthetic 12-keto derivatives tended to be more active against HCMV than the corresponding 12-OH congeners, which were more active against HIV-1. It appeared that the 7,8-unsaturated double bond in the chromene ring played a certain role in maintaining activities against both HCMV and HIV-1. Saturation of the double bond increased the EC50 values against both viruses, with concomitant increase in toxicity. The calanolide compounds reported here are the first non-nucleoside analogues capable of inhibiting both HIV-1 and HCMV and, therefore, may be useful chemoprophylactic agents for HCMV in HIV-infected people or vice versa.