New bioactive aromatic compounds from Vismia guianensis

Visible Light-Induced Metal-free Arylation of Coumarin-3-carboxylates with Arylboronic Acids

The present work represents a novel methodology for the selective arylation of coumarin-3-carboxylates with arylboronic acids via a photochemical route, marking the first-ever attempt for the direct alkenyl C-H arylation using rose bengal as a photocatalyst, which is a readily available and cost-effective alternative to transition metal catalysis. The reaction proceeds smoothly in MeOH/H2O solvent media in the presence of radical initiator affording the arylated products in good yields (60-80 %). The reaction parameters such as visible light, radical initiator, oxidant, anhydrous solvent, and inert atmosphere play a crucial role for the success of this methodology. The substituents present on the substrate show a significant effect on the conversion. This study provides a valuable contribution to the field of organic synthesis offering a new and efficient approach to the arylation of coumarin-3-carboxylic acid esters with a broad substrate scope and high functional group tolerance. It is a versatile method and provides a direct access to biologically relevant 4-arylcoumarin-3-carboxylates.

Brønsted Acid-Mediated Multicomponent One-Pot Approach to Direct Construction of 4-Aryl-hydrocoumarin Derivatives

The facile and efficient synthesis of a unique class of 4-aryl-hydrocoumarins having enormous applications in medicinal chemistry and natural products is presented. We have for the first time developed a Brønsted acid-catalyzed, multicomponent, one-pot approach for producing various 4-aryl-coumarin derivatives. The feedstock availability of these precursors allowed access to a wide range of 2-chromanone derivatives in good to excellent yields under mild conditions. The practicality of this protocol was justified by the synthesis of bioactive compounds, late-stage functionalization of natural products, and gram-scale synthesis.

Efficient and stereoselective synthesis of sugar fused pyrano[3,2-c]pyranones as anticancer agents

A highly stereoselective, efficient and facile route was achieved for the synthesis of novel and biochemically potent sugar fused pyrano[3,2-c]pyranone derivatives starting from inexpensive, naturally occurring d-galactose and d-glucose. First, β-C-glycopyranosyl aldehydes were synthesized from these d-hexose sugars in six steps, with overall yields 41-55%. Next, two different 1-C-formyl glycals were synthesized from these β-C-glycopyranosyl aldehydes by treatment in basic conditions. The optimization of reaction conditions was carried out following reactions between 1-C-formyl galactal and 4-hydroxycoumarin. Next, 1-C-formyl galactal and 1-C-formyl glucal were treated with nine substituted 4-hydroxy coumarins at room temperature (25 °C) in ethyl acetate for ∼1-2 h in the presence of l-proline to obtain exclusively single diastereomers of pyrano[3,2-c]pyranone derivatives in excellent yields. Four compounds were found to be active for the MCF-7 cancer cell line. The MTT assay, apoptosis assay and migration analysis showed significant death of the cancer cells induced by the synthesized compounds.

Schomburginones A‒J, geranylated benzophenones from the leaves of Garcinia schomburgkiana and their cytotoxic and anti-inflammatory activities

Ten undescribed benzophenones, schomburginones A-J, together with 14 known analogs were isolated from the leaves of Garcinia schomburgkiana, an edible plant native to the Indochina region. The structures of the undescribed compounds were elucidated by NMR combined with HRMS spectroscopy, while their absolute configurations were determined using ECD and single-crystal X-ray diffraction analysis. The isolated metabolites represent benzophenone derivatives containing a modified monoterpene unit, including tri- and tetracyclic skeletons, which are rarely found in genus Garcinia. The cytotoxic evaluation on three cancerous cell lines demonstrated that schomburginone G, schomburginone H, and 3-geranyl-2,4,6-trihydroxybenzophenone were active against HeLa cells with IC₅₀ values in the range of 12.2-15.7 μM, respectively, and selective compared to the non-cancerous L929 cells (SI > 3.5). In addition, the three cytotoxic compounds together with clusiacyclol A showed significant NO inhibitory activity in RAW 264.7 macrophage cells over 85% inhibition without obvious cytotoxicity at a final concentration of 100 μM. The promising activities of these compounds in cytotoxic and anti-inflammatory assays make them attractive for further study in the development of anticancer drugs.

The Anti-Virulence Effect of Vismia guianensis against Candida albicans and Candida glabrata

In folk medicine, Vismia guianensis is used to treat skin diseases and mycoses in the Amazon region. We evaluated the anti-Candida activity of the hydroalcoholic extract from the leaves of Vismia guianensis (EHVG). HPLC-PDA and FIA-ESI-IT-MSⁿ were used to chemically characterize EHVG. The anti-Candida activity was determined in vitro by the minimum inhibitory concentrations (MIC) against Candida glabrata (ATCC-2001); Candida albicans (ATCC-90028, ATCC-14053, and ATCC-SC5314), and C. albicans clinical isolates. EHVG effects on adhesion, growth, and biofilm formation were also determined. Molecular docking was used to predict targets for EHVG compounds. The main compounds identified included anthraquinone, vismione D, kaempferol, quercetin, and vitexin. EHVG was fungicidal against all tested strains. C. albicans ATCC 14053 and C. glabrata ATCC 2001 were the most sensitive strains, as the extract inhibited their virulence factors. In silico analysis indicated that vismione D presented the best antifungal activity, since it was the most effective in inhibiting CaCYP51, and may act as anti-inflammatory and antioxidant agent, according to the online PASS prediction. Overall, the data demonstrate that EHVG has an anti-Candida effect by inhibiting virulence factors of the fungi. This activity may be related to its vismione D content, indicating this compound may represent a new perspective for treating diseases caused by Candida sp.

Simultaneous Enantiodivergent Synthesis of Diverse Lactones and Lactams via Sequential One-Pot Enzymatic Kinetic Resolution-Ring-Closing Metathesis Reactions

One of the goals of diversity-oriented synthesis is to achieve the structural diversity of obtained compounds. As most biologically active compounds are chiral, it is important to develop enantioselective methods of their synthesis. The application of kinetic resolution in DOS is problematic because of low efficiency (max. 50% yield) and many purification steps. The further derivatization of kinetic resolution products in DOS leads to the formation of a narrow library of compounds of the same stereochemistry. To overcome these limitations, we present a new concept in which the kinetic resolution is combined, the subsequent reaction of which in a one-pot protocol leads to the simultaneous formation of two skeletally and enantiomerically diverse platform molecules for DOS. Their further derivatization can gain access to a double-sized library of products in respect to a classical approach. The validity of our concept was evidenced in enzymatic kinetic resolution followed by a ring-closing metathesis cascade. From racemic carboxylic acid ester, a simultaneous formation of enantiopure lactones and lactams was achieved. These compounds are important building blocks in organic and medicinal chemistry and until now were synthesized in separate procedures.

Polyprenylated Acylphloroglucinols With Different Carbon Skeletons From the Fruits of Garcinia multiflora

Eleven new polycyclic polyprenylated acylphloroglucinols (PPAPs, 1-11) and three new monocyclic polyprenylated acylphloroglucinols (MPAPs, 12-14), together with ten known analogues were isolated from the fruits of Garcinia multiflora. These PPAPs belong to three types including the bicyclic polyprenylated acylphloroglucinols (BPAPs), the caged PPAPs, and the complicated PPAPs. Their structures and absolute configurations were determined through HRESIMS, NMR spectroscopy data, electronic circular dichroism (ECD) calculations, and gauge-independent atomic orbital (GIAO) NMR calculations with DP4+ analyses. Moreover, compounds 2 and 7 exhibited moderate cytotoxicity against three human cancer lines (MCF-7, T98, and HepG2) with IC50 values ranging from 9.81 ± 1.56 to 17.00 ± 2.75 μM.

Further prenylated anthranoids from Harungana madagascariensis

Ten undescribed anthranoids, including three anthraquinone acetals as racemic mixtures, (±)-kenganthranol G-I, and seven prenylated anthranols, (±)-kenganthranol J-M and harunganol G-I, together with thirteen known compounds, were isolated from the stem bark of Harungana madagascariensis. The structures of (±)-kenganthranol G and (±)-kenganthranol J were confirmed by X-ray crystallography. (±)-Kenganthranol G was separated into (+)-kenganthranol G and (-)-kenganthranol G by chiral HPLC and their absolute configurations were established by electronic circular dichroism. (±)-Kenganthranol L displayed α-glucosidase inhibitory activity with an IC₅₀ of 4.4 μM.

Biotransformation of Benzoate to 2,4,6-Trihydroxybenzophenone by Engineered Escherichia coli

The synthesis of natural products by E. coli is a challenging alternative method of environmentally friendly minimization of hazardous waste. Here, we establish a recombinant E. coli capable of transforming sodium benzoate into 2,4,6-trihydroxybenzophenone (2,4,6-TriHB), the intermediate of benzophenones and xanthones derivatives, based on the coexpression of benzoate-CoA ligase from Rhodopseudomonas palustris (BadA) and benzophenone synthase from Garcinia mangostana (GmBPS). It was found that the engineered E. coli accepted benzoate as the leading substrate for the formation of benzoyl CoA by the function of BadA and subsequently condensed, with the endogenous malonyl CoA by the catalytic function of BPS, into 2,4,6-TriHB. This metabolite was excreted into the culture medium and was detected by the high-resolution LC-ESI-QTOF-MS/MS. The structure was elucidated by in silico tools: Sirius 4.5 combined with CSI FingerID web service. The results suggested the potential of the new artificial pathway in E. coli to successfully catalyze the transformation of sodium benzoate into 2,4,6-TriHB. This system will lead to further syntheses of other benzophenone derivatives via the addition of various genes to catalyze for functional groups.

Catalytic Asymmetric Hydrogenation of 3-Ethoxycarbonyl Quinolin-2-ones and Coumarins

A protocol of iridium catalyzed asymmetric hydrogenation of 4-alkyl substituted 3-ethoxycarbonyl quinolin-2-ones and coumarins has been reported, providing a wide range of chiral dihydroquinolin-2-ones and dihydrocoumarins in high yields with excellent enantioselectivities (up to 99% ee) and high turnover numbers (up to 28 000). This efficient protocol was successfully applied for the synthesis of MPR3160 and the key chiral intermediate of R-106578.

Chiral Fe(ii) complex catalyzed enantioselective [1,3] O-to-C rearrangement of alkyl vinyl ethers and synthesis of chromanols and beyond

A highly efficient enantioselective [1,3] O-to-C rearrangement of racemic vinyl ethers that operates under mild conditions was developed. This method with chiral ferrous complex catalyst provided an efficient access to a wide range of chromanols with high yields and excellent enantioselectivities. In addition, an important urological drug (R)-tolterodine and others were easily obtained after simple transformations.

Eco-friendly synthesis of fused pyrano[2,3-b]pyrans via ammonium acetate-mediated formal oxa-[3 + 3]cycloaddition of 4H-chromene-3-carbaldehydes and cyclic 1,3-dicarbonyl compounds

Various substituted polycyclic pyrano[2,3-b]pyrans were synthesized via the condensation of 4H-chromene-3-carbaldehydes and their areno-condensed analogues with hetero- and carbocyclic 1,3-dicarbonyl compounds in acetic acid. Ammonium acetate was used as a green catalyst for the reaction. The process also involves the subsequent Knoevenagel condensation and 6π-electrocyclization of the 1-oxatriene intermediates formed. Fused pyridines were isolated as the products of the conjugated addition of ammonia to 1-oxatriene intermediates while using carbocyclic 1,3-dicarbonyl compounds and increasing the reaction time, indicating the reversibility of the electrocyclization stage. The calculated values of the Gibbs free energies and reaction rate constants for the 1-oxatriene – 2H-pyran equilibrium also testified to the irreversibility of pyrano[2,3-b]pyran formation in the case of using of heterocyclic 1,3-dicarbonyl compounds.

We report the eco-friendly synthesis of fused pyrano[2,3-b]pyrans via ammonium acetate-mediated formal oxa-[3 + 3]-cycloaddition of 4H-chromene-3-carbaldehydes and cyclic 1,3-dicarbonyl compounds.

Anti-inflammatory activity of Vismia guianensis (Aubl.) Pers. extracts and antifungal activity against Sporothrix schenckii

ETHNOPHARMACOLOGICAL RELEVANCE

Vismia guianensis (Aubl.) Pers. is traditionally used in North and Northeast of Brazil for the treatment of dermatomycoses. Since the strategy associating immunomodulators with antifungal drugs seems to be promissory to improve the treatment efficacy in fungal infections, we aimed to investigate the antifungal activity of V. guianensis ethanolic extract of leaves (VGL) and bark (VGB) against Sporothrix schenckii ATCC 16345 and their antinflammatory activities.

MATERIAL AND METHODS

The extracts were analyzed by HPLC-DAD-IT MS/MS for in situ identification of major compounds. Antifungal activity was evaluated in vitro (microdilution test) and in vivo using a murine model of S. schenckii infection. The production of TNF-α, IFN-γ, IL-4, IL-10 and IL-12 by measured by ELISA, as well as measured the production and inhibition of the NO after treatment with the plant extracts or itraconazole (ITR).

RESULTS

Two O-glucosyl-flavonoids and 16 prenylated benzophenone derivatives already described for Vismia were detected. Both VGL and VGB showed significant antifungal activity either in in vitro assay of microdilution (MIC=3.9µg/mL) and in vivo model of infection with reduction of S. schenckii load in spleen. It was also observed a predominance of reduction in the production of NO and the proinflammatory cytokines evaluated except TNFα, but with stimulation of IL-10, as evidence of a potential anti-inflammatory effect associated.

CONCLUSION

The results showed that both VGL and VGB have a significant antifungal against S. schenckii and an anti-inflammatory activity. These results can support the use of these extracts for alternative treatment of sporotrichosis.

Enantioselective Synthesis of 3,5,6-Substituted Dihydropyranones and Dihydropyridinones using Isothiourea-Mediated Catalysis

The scope of dihydropyranone and dihydropyridinone products accessible by isothiourea-catalyzed processes has been expanded and explored through the use of 2-N-tosyliminoacrylates and 2-aroylacrylates in a Michael addition-lactonization/lactamization cascade reaction. Notably, to ensure reproducibility it is essential to use homoanhydrides as ammonium enolate precursors with 2-aroyl acrylates, while carboxylic acids can be used with 2-N-tosyliminoacrylates, delivering a range of 3,5,6-substituted dihydropyranones and dihydropyridinones with high enantioselectivity (typically >90 % ee). The derivatization of the heterocyclic core of a 3,5,6-substituted dihydropyranone through hydrogenation is also reported.

Differential Sequestration of a Cytotoxic Vismione from the Host Plant Vismia baccifera by Periphoba arcaei and Pyrrhopyge thericles

We sought to compare the abilities of the specialist Lepidoptera Pyrrhopyge thericles (Hesperiidae) and the generalist Periphoba arcaei (Saturniidae) to assimilate three highly cytotoxic compounds from their larval host plant, Vismia baccifera (Clusiaceae) and to determine whether either insect discriminated in its assimilation of the compounds that are structurally similar but of variable cytotoxicity. Vismione B (1), deacetylvismione A (2), and deacetylvismione H (3) are cytotoxic compounds isolated from V. baccifera. Compound 1 was found in the 2nd and 3rd instars of P. arcaei, but not in the mature larvae or the pupae. Pyrrhopyge thericles assimilated trace quantities of compound 1 and deacetylvismione A (2), which were both found in the 3rd and 4th instars. In extracts of V. baccifera, compound 2 is present at levels approximately 6-fold greater than compound 1, indicating that the generalist P. arcaei is capable of selectively sequestering cytotoxic compounds from its host plant. Compounds 1 and 2 show comparable cytotoxicities in three different cancer cell lines, suggesting that properties other than cytotoxicity are responsible for the selective sequestration of 1 by P. arcaei. This study represents the first time that sequestration of this class of compounds has been recorded in the Lepidoptera.

Structural diversity and bioactivities of natural benzophenones

Natural benzophenones are a class of compounds with more than 300 members, mainly in the Clusiaceae family. We review key benzophenones, and provide an in-depth discussion of their great structural diversity and biological activity.

Chemistry and biology of genus Vismia

CONTEXT

Many herbal remedies have been employed in the treatment and management of various human ailments since the beginning of human civilization. Vismia is an extensive genus of the family Hypericaceae and consists of small trees inhabiting the tropical and subtropical regions of South and Central America. Within the framework of an International Cooperative Biodiversity Groups project, three Vismia species were studied for their potential anticancer activity.

OBJECTIVES

This review is an extensive study of the available scientific literature published and comprises of the ethnopharmacological, phytochemical and therapeutic potential of genus of plants under the umbrella Vismia.

METHODS

The present review includes 134 natural products with 47 references compiled from the major databases, viz., Chemical Abstracts, Science Direct, SciFinder, PubMed, Dr. Dukes Phytochemical and Ethnobotany, CIMER, and InteliHealth.

RESULTS

An exhaustive survey of the accessed literature revealed that flavonoids, flavanols, xanthones, anthraones, anthraquinones, benzophenones, lignans, steroids, monoterpenes and triterpenes constituted the major classes of phytoconstituents of this genus. Pharmacological reports revealed that it is used for skin diseases such as dermatitis, leprosy, syphilis, herpes, scabies and eczemas, and as an anticancer for human breast, CNS, and lung cancer cell lines.

CONCLUSION

Genus Vismia plants seem to hold great potential for an in-depth investigation towards discovering biological activities, especially for the treatment of cancers affecting our society. Through this review, the authors hope to attract the attention of natural product researchers throughout the world to focus on the unexplored potential of Vismia plants, with the view of developing new formulations with an improved therapeutic value.

ent-Kaurane and cembrane diterpenoids from Isodon sculponeatus and their cytotoxicity

Nine new ent-kauranoids, sculponins D-L (1-9), and 14 known diterpenoids (10-23) were isolated from the aerial parts of Isodon sculponeatus. The structures of the new diterpenoids were determined by detailed interpretation of their 1D and 2D NMR spectra and HRESIMS. The isolated compounds were evaluated for their cytotoxic activities against a small panel of human cancer cell lines.

Fragmentation pathways of polycyclic polyisoprenylated benzophenones and degradation profile of nemorosone by multiple-stage tandem mass spectrometry

Nemorosone is a polycyclic polyisoprenylated benzophenone (PPBs) with strong cytotoxic activity. It is the major constituent of Clusia rosea floral resin and brown Cuban propolis. Other PPBs found in Cuban propolis are oxidized and cyclized derivatives of nemorosone. The instability of PPBs carrying an enolizable 1,3-diketone system has been suggested, and the elucidation of this aspect is very fundamental for the evaluation of their biologic activity. Electrospray ionization multistage tandem mass spectrometry (ESI-MS(n)) was employed to shed light on the origin of these derivatives of nemorosone and to define the stability of this natural product. For this purpose, we initially performed MS(n) experiments on seven related PPBs to obtain useful information for structural characterization of this class of compounds and to identify the degradation products of nemorosone. The proposed fragmentation pathways, supported by exact mass measurements, allowed the nature of side chains on the bicyclo core and the type and position of their modifications to be established. In a second part, the degradation profile of nemorosone under different conditions was investigated to assess the possible effects of isolation procedures, climatic, and storage conditions on its stability. Our results reveal that nemorosone undergoes rapid degradation in n-hexane and chloroform solutions. The degradation products, identified by HPLC-ESI/MS(n) and NMR, are identical to derivatives of nemorosone previously isolated from propolis and plants. Thus, these PPBs are artefacts formed predominantly during the extraction and purification procedures.

Antimicrobial activities of methanol extract and compounds from stem bark of Vismia rubescens

ETHNOPHARMACOLOGICAL RELEVANCE

The plant, Vismia rubescens (Guttiferae) is popularly used in Cameroon and in several parts of Africa as febrifugal and for the treatment of various microbial infections (skin diseases, diarrhoea and venereal diseases).

AIM OF THE STUDY

This study was mapped out to evaluate the antimicrobial activities of the methanol extract and compounds from the stem bark of Vismia rubescens.

MATERIALS AND METHODS

Structures of the compounds obtained after column chromatography of the methanol-soluble fraction were determined by spectroscopy and in comparison with published data. The broth micro-dilution method was used to evaluate the antimicrobial activities against three bacteria species (Salmonella typhi, Staphylococcus aureus and Pseudomonas aeruginosa) and four yeast species (Candida albicans, Candida tropicalis, Candida parapsilosis and Cryptococcus neoformans).

RESULTS

Chemical analysis of the methanol extract from the stem bark of Vismia rubescens yielded five known compounds 1,4,8-trihydroxyxanthone (1), 1,7-dihydroxyxanthone (2), physcion (3), friedelin (4) and friedelanol (5). The crude extract and compounds 1, 2 and 3 exhibited both antibacterial and antifungal activities that varied between the microbial species (MIC=3.12-1000 microg/ml). Compounds 2 and 3 were the most active (MIC=3.12-100 microg/ml) while Staphylococcus aureus and Pseudomonas aeruginosa were sensitive to all the tested compounds. The antimicrobial activity of this plant as well as that of compounds 1 and 2 is being reported here for the first time.

CONCLUSION

These results provide promising baseline information for the potential use of this plant as well as some of the isolated compounds in the treatment of skin diseases and diarrhoea.

Anthraquinones from the fruits of Vismia laurentii

Phytochemical study of the fruits of Vismia laurentii resulted in the isolation of five structurally related compounds. Three of them are constituents, namely, laurentiquinone A (1) (methyl 1,6,8-trihydroxy-3-methyl-7-(3-methylbut-2-enyl)-9,10-dioxo-9,10-dihydroanthracene-2-carboxylate), laurentiquinone B (2) (methyl 5,7-dihydroxy-2,2,9-trimethyl-6,11-dioxo-6,11-dihydro-2H-anthra[2,3-b]pyran-8-carboxylate) and laurentiquinone C (3) (methyl 9-(ethanoyloxymethyl)-5,7-dihydroxy-2,2-dimethyl-6,11-dioxo-6,11-dihydro-2H-anthra[2,3-b]pyran-8-carboxylate) and two are known compounds, emodin (4) and isoxanthorin (5). Their structures were elucidated by spectroscopic means. Crude extracts of hexane and EtOAc showed anti-plasmodial activity against the W2 strain of Plasmodium falciparum.

Synthesis of Novel Spiro Compounds using Anthrone and Pyrazole-5-thione Moieties: A Michael Addition approach

Novel routes for the synthesis of spiro derivatives anthrone have been designed using a Michael addition reaction followed by a Dieckmann condensation and Thorpe–Ziegler cyclisation. Bis-Michael addition of pyrazole-5-thione with 1,5-diarylpenta-1,4-dien-3-one gave directly a spiro derivative of pyrazole-5-thione. An enol lactone was synthesised by using mono Michael addition on dimedone, followed by hydrolysis and condensation.

Relationships between inhibitory activity against a cancer cell line panel, profiles of plants collected, and compound classes isolated in an anticancer drug discovery project

In an attempt to determine the relationships between the plant profiles (country of collection, taxonomy, plant part) and the compound classes isolated with cytotoxic activity against a panel of human tumor cell lines, the data compiled from a 15-year anticancer drug-discovery project were subjected to an analysis of variance (ANOVA). The results indicate significant trends in cytotoxic activity relative to collection location, taxonomy, plant part, and compound classes isolated. Plant collections were made in tropical forests in six countries, with collections from Ecuador resulting in higher activity than those from Indonesia and Peru. Interestingly, collections from Florida were not statistically different than those from the countries with higher biodiversity. One hundred and forty-five families were represented in the collections, with the Clusiaceae, Elaeocarpaceae, Meliaceae, and Rubiaceae having low ED50 (half maximal effective dose) values. Especially active genera included Aglaia, Casearia, Exostema, Mallotus, and Trichosanthes. Roots and below-ground plant materials were significantly more active than above-ground materials. Cucurbitacins, flavaglines, anthraquinones, fatty acids, tropane alkaloids, lignans, and sesquiterpenoids were significantly more active than xanthones and oligorhamnosides. The results from this study should serve as a guide for future plant collection endeavors for anticancer drug discovery.

Laurentixanthones A and B, antimicrobial xanthones from Vismia laurentii

A phytochemical investigation of the constituents of the roots of Vismia laurentii has resulted in the isolation of two xanthone derivatives named laurentixanthone A (1) (6-hydroxy-3,3-dimethyl-11-(3-methylbut-2-enyl)pyrano[2,3-c]xanthen-7(3H)-one) and laurentixanthone B (2) (1-hydroxy-5,6,7,8-tetramethoxyxanthone), along with 11 known compounds: 1,7-dihydroxyxanthone, vismiaquinone, vismiaquinone B, bivismiaquinone, 3-geranyloxy-6-methyl-1,8-dihydroxyanthraquinone, O(1)-demethyl-3',4'-deoxypsorospermin-3',4'-diol, 6-deoxyisojacareubin, 1,8-dihydroxy-6-methoxy-3-methylanthraquinone, kaempferol, friedelin and stigmasterol. The structures of compounds were established by means of spectroscopic methods. Furthermore, the compounds were screened for antimicrobial activities in vitro.

A DNA strand-nicking principle of a higher plant, Caesalpinia sappan

To find anticancer agents from higher plants, DNA strand-scission assay method was employed for bioassay-guided fractionation as well as for screening the crude extracts. During the screening, an ethyl acetate extracts of the heartwood of Caesalpinia sappan L. (Leguminosae) exhibited potent DNA strand-scission activity. Therefore, the ethyl acetate extracts of the dried heartwood of C. sappan was subjected to the bioassay-guided fractionation, which led to the isolation of a known compound, brazilin (1) as the active constituent. In addition, caesalpine J (2) was also isolated as an inactive constituent.