Cytotoxic polyisoprenes and glycosides of long-chain fatty alcohols from Dimocarpus fumatus

Three new meroterpenoids from Sargassum macrocarpum and their inhibitory activity against amyloid β aggregation

Amyloid β (Aβ) is thought to be involved in the pathogenesis of Alzheimer's disease (AD). Aβ aggregation in the brain is considered the cause of AD. Therefore, inhibiting Aβ aggregation and degrading existing Aβ aggregates is a promising approach for the treatment and prevention of the disease. In searching for inhibitors of Aβ42 aggregation, we found that meroterpenoids isolated from Sargassum macrocarpum possess potent inhibitory activities. Therefore, we searched for active compounds from this brown alga and isolated 16 meroterpenoids, which contain three new compounds. The structures of these new compounds were elucidated using two-dimensional nuclear magnetic resonance techniques. Thioflavin-T assay and transmission electron microscopy were used to reveal the inhibitory activity of these compounds against Aβ42 aggregation. All the isolated meroterpenoids were found to be active, and compounds with a hydroquinone structure tended to have stronger activity than those with a quinone structure.

Zenkeramide: a new iso-benzofuranone propanamide and urease inhibitory constituents of Celtis zenkeri Engl stem bark (Ulmaceae)

A new iso-benzofuranone propanamide: 3-(3-oxo-1, 3-dihydroisobenzofuran-1-yl) propanamide (zenkeramide) (1) along with three known compounds: Trans-N-coumaroyltyramine (2), β-Sitosterol (3) and β-sitosterol-3-0-β-D-glucopyranoside (4) were isolated from the ethyl acetate fraction of the stem-bark of Celtis zenkeri Engl (Ulmaceae). The structure of the new compound was elucidated by extensive spectroscopic analysis. The compounds were examined for Urease Inhibitory Activity. Compounds 1 and 2 showed moderate activities (IC₅₀ values (μM) of 42.3 ± 0.19 and 45.2 ± 0.55, respectively), while compounds 3 and 4 were potent inhibitors of the Jack bean urease (IC₅₀ values (μM) of 20.3 ± 0.37and 27.6 ± 0.52, respectively), when compared to the standard inhibitor (thiourea- IC₅₀ 21.5 ± 0.47). The isolation of all the compounds from C. zenkeri and the urease activity of compounds 1 and 2 are reported for the first time.

A new ent-clerodane diterpene from Detarium microcarpum Guill. & Perr. and its protective potential for osteoporosis

A new clerodane diterpene, named 6α-hydroxy-3,13E-clerodien-15-oic acid (1), together with a known clerodane diterpene (2), four known labdane diterpenes (3-6), a triterpenoid (7), a known steroid (8), and two benzenoid compounds (9 and 10) were isolated from Detarium microcarpum Guill. & Perr. The structures of all obtained compounds were determined by chemical properties and spectroscopic evidence, accompanied by comparisons with data in the literature. Electronic circular dichroism (ECD) was performed for compounds 1-4 to confirm the absolute configuration. Compounds 1-3 and 8-10 were evaluated for the protective effect on osteoblasts. Compound 1 was observed to increase the proliferation of dexamethasone (DEX)-treated MC3T3-E1 cells significantly at 1 μM, which was comparable with the positive control geniposide at 10 μM. The results were further confirmed by flow cytometry analysis. In addition, compound 1 increased the level of alkaline phosphatase (ALP) and mineralization in osteoblasts inhibited by DEX. Moreover, Compound 9 (vanillic acid) showed a pronounced inhibition (IC₅₀ 6.5 ± 0.6 μM) on reactive oxygen species (ROS) production, and 10 (4-O-methyl gallic acid) showed a good inhibition with IC₅₀ as 103.3 ± 2.2 μM, compared with the standard drug ibuprofen (IC₅₀ 54.2 ± 9.2 μM). Besides, compounds 1-3 and 8-10 were non-cytotoxic against MCF-7, NCI-H460, Hela, and BJ cell lines.

Isolation and characterization of chemical constituents from Chaerophyllum bulbosum roots and their enzyme inhibitory and antioxidant effects

Isolation and bioactive effects of the roots of Chaerophyllum bulbosum L. were firstly investigated herein. Enzyme (acetylcholinesterase, butyrylcholinesterase, urease, α-amylase, α-glucosidase, and tyrosinase) inhibitory effects of C. bulbosum root extracts were tested. Three known compounds, n-heptadecanyl eicosanoate (1), stigmasterol (2), and β-sitosterol-3-O-β-d-glucopyranoside (3) were isolated from C. bulbosum. Antioxidant and enzyme inhibitory effects of isolated compounds were investigated. The hexane extract (IC₅₀: 349.58 ± 0.06 μg/mL) displayed a higher α-glucosidase inhibitory effect than the standard (IC₅₀: 378.66 ± 0.14 μg/mL). The best inhibitory effect was found in compound 2 on AChE (46.40 ± 0.31%), BChE (56.41 ± 0.54%), and urease (92.47 ± 0.11%); compound 1 on α-amylase (22.27 ± 0.61%); and compound 3 on α-glucosidase (12.43 ± 0.25%) and tyrosinase (19.00 ± 0.16%). All isolated compounds showed moderate antioxidant effects in all assays. This study contributes to the therapeutic uses of Chaerophyllum roots and emphasizes the value of C. bulbosum species for the development of novel therapeutic agents.

Chemical Composition and New Biological Activities of Essential Oil and Hydrosol of Hypericum perforatum L. ssp. veronense (Schrank) H. Lindb

The chemical profile, antiproliferative, antioxidant and antiphytoviral activities of the species Hypericum perforatum ssp. veronense (Schrank) H. Lindb. (Clusiaceae) were investigated. Free volatiles were isolated and the chemical composition was determined in the lipophilic fraction (essential oil) and for the first time in the water fraction (hydrosol). The aim is to provide phytochemical data for H. perforatum ssp. veronense useful for distinguishing ssp. veronense from ssp. angustifolium, as there are taxonomic disagreements between them and the composition of the secretory products may be helpful in this respect. In the essential oil, the most abundant compounds identified were α-pinene and n-nonane, while in the hydrosol, myrtenol, carvacrol and α-pinene were the most abundant. Overall, the class of monoterpenes and oxygenated monoterpenes dominated in the EO and hydrosol samples. The essential oil showed high antioxidant activity, in contrast to the antiproliferative activity, where the hydrosol showed exceptional activity against three cancer cell lines: Hela (cervical cancer cell line), HCT116 (human colon cancer cell line) and U2OS (human osteosarcoma cell line). Both the essential oil and hydrosol showed antiphytoviral activity against tobacco mosaic virus infection on the local host plants. This is the first report dealing with biological activities of hydrosol of H. perforatum ssp. veronense, and the obtained results suggest that this traditional medicinal plant is a valuable source of volatiles with promising antiproliferative, antioxidant and antiphytoviral activities.

Two new terpenoids from the leaves of callicarpa macrophylla

Two new terpenoids (1-2) and seven known compounds (3-9) were isolated from methanol extract of Callicarpa macrophylla leaves. Their structures were determined to be ent-7α,16β,17,18-tetrahydroxykaur-15-one (1), 3β-acetoxy-urs-12-ene-11-one-12-ol (2), ent-1β-acetoxy-7α,14β-dihydroxykaur-16-en-15-one (3), 3β-acetoxy-11α,13β-dihydroxyolean-12-one (4), β-amyrin (5), spinasterol (6), ursolic acid (7), β-sitosterol (8), and daucosterol (9) by analyses of their MS, NMR spectroscopic data and by comparison with those reported in the literature. Compounds 1 - 4, and 7 displayed potential cytotoxic activity towards HepG-2, LU-1, and MCF-7 human cancer cell lines with IC50 values ranging from 0.46 ± 0.21 to 18.14 ± 0.33 μM. Compound 6 showed IC50 values of 14.17 ± 0.21 and 5.72 ± 0.42 μM against Hep-G2 and MCF-7 cell lines, respectively.

Rhamnose in plants - from biosynthesis to diverse functions

In plants, the deoxy sugar l-rhamnose is widely present as rhamnose-containing polymers in cell walls and as part of the decoration of various specialized metabolites. Here, we review the current knowledge on the distribution of rhamnose, highlighting the differences between what is known in dicotyledoneuos compared to commelinid monocotyledoneous (grasses) plants. We discuss the biosynthesis and transport of UDP-rhamnose, as well as the transfer of rhamnose from UDP-rhamnose to various primary and specialized metabolites. This is carried out by rhamnosyltransferases, enzymes that can use a large variety of substrates. Some unique characteristics of rhamnose synthases, the multifunctional enzymes responsible for the conversion of UDP-glucose into UDP-rhamnose, are considered, particularly from the perspective of their ability to convert glucose present in flavonoids. Finally, we discuss how little is still known with regards to how plants rescue rhamnose from the many compounds to which it is linked, or how rhamnose is catabolized.

Chemical constituents from the branches and leaves of Alchornea annamica

Phytochemical investigation of the branches and leaves of Alchornea annamica led to isolation of ten secondary metabolites, including two new megastigmane glucosides alnamicosides A (1) and B (2). The structure elucidation was confirmed by 1 D and 2 D NMR, ECD as well as HR-QTOF-MS experiments. The megastigmane derivatives 1 - 3 exhibited inhibitory effects on LPS-induced NO production in RAW264.7 cells with IC₅₀ values of 78.72 ± 1.90, 77.40 ± 9.40 and 82.16 ± 4.56 µM, respectively. This is the first report on chemical constituents and biological activity of the plant A. annamica.

Selective Cytotoxicity and Antioxidant Effects of Compounds from Dioscorea membranacea Rhizomes

Bioassay-guided isolation was used to separate the active ingredients of the ethanolic extract of Dioscorea membranacea by testing cytotoxic activity against three human cancer cell lines, i.e. large cell lung carcinoma (COR-L23), colon cell line (LS-174T) and breast cancer cell line (MCF-7), and two normal human cell lines, keratinocytes (SVK-14) and normal human fibroblasts (HF), using the SRB assay. The DPPH test for antioxidant activity was also employed, as was a test for LDH release as an indicator of damage to the cell membrane. Eight compounds were isolated, two naphthofuranoxepins (dioscorealides A [1] and B [2]), a 1,4-phenanthraquinone (dioscoreanone [3]), three steroids (β-sitosterol [4], stigmasterol [5] and β-D-sitosterol glucoside [8]) and two steroid saponins diosgenin-(3- O-α-L-rhamnopyranosyl (1→2)-β-D-glucopyranoside [6] and diosgenin 3- O-β-D-glucopyranosyl (1→3)-β-D-glucopyranoside [7]). Cytotoxic activity of 2, 3 and 6 was shown against three cancer cell lines, and 2 showed selective cytotoxic activity against lung and breast cancer, but was less active against the two normal cells, and was not toxic to cell membranes in the LDH assay. The highest antioxidant activity was shown by 3.

Ethnobotany, phytochemistry and pharmacology of Arctotis arctotoides (L.f.) O. Hoffm.: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Arctotis arctotoides (Asteraceae) is part of the genus Arctotis. Arctotis is an African genus of approximately 70 species that occur widely in the African continent with diverse medicinal values. This plant is used for the treatment of indigestion and catarrh of the stomach, epilepsy, topical wounds and skin disorders among the ethnic groups in South Africa and reported to have a wide spectrum of pharmacological properties.

AIM OF THE REVIEW

The aim of the present review is to appraise the botany, traditional uses, phytochemistry, pharmacological potential, analytical methods and safety issues of A. arctotoides. Additionally, this review will help to fill the existing gaps in knowledge and highlight further research prospects in the field of phytochemistry and pharmacology.

MATERIALS AND METHODS

Information on A. arctotoides was collected from various resources, including books on African medicinal herbs and Zulu medicinal plants, theses, reports and the internet databases such as SciFinder, Google Scholar, Pubmed, Scopus, Web of Science, and Mendeley by using a combination of various meaningful keywords. This review surveys the available literature of the species from 1962 to April 2017.

RESULTS

In vitro and in vivo studies of the medicinal properties of A. arctotoides were reviewed. The main isolated and identified compounds were reported as sesquiterpenes, farnesol derivatives, germacranolide, guaianolides and some steroids, of which, nine were reported as antimicrobial. Monoterpenoids and sesquiterpenoids were the predominant essential oil compound classes of the leaves, flowers, stems and roots. The present review revealed potential pharmacological properties such as anti-oxidant, antibacterial, antifungal and anticancer activities of plant extracts as well as isolated compounds. Moreover, the review reports the safety profile (toxicity) of the crude extracts that had been screened on brine shrimps, rats and human cell lines.

CONCLUSIONS

The present review has focused on the phytochemistry, botany, ethnopharmacology, biological activities and toxicological information of A. arctotoides. On the basis of reported data, A. arctotoides has emerged as a good source of natural medicine for the treatment of microbial infections, skin diseases, anti-inflammatory and anticancer agents and also provides new insights for further isolation of new bioactive compounds, especially the discovery of antimicrobial, anti-inflammatory and anticancer novel therapeutic lead drug molecules. Additionally, intensive investigations regarding pharmacological properties, safety assessment and efficacy with their mechanism of action could be future research interests before starting clinical trials for medicinal practices.

Enzymatic Synthesis of Rhamnose Containing Chemicals by Reverse Hydrolysis

Rhamnose containing chemicals (RCCs) are widely occurred in plants and bacteria and are known to possess important bioactivities. However, few of them were available using the enzymatic synthesis method because of the scarcity of the α-L-rhamnosidases with wide acceptor specificity. In this work, an α-L-rhamnosidase from Alternaria sp. L1 was expressed in Pichia pastroris strain GS115. The recombinant enzyme was purified and used to synthesize novel RCCs through reverse hydrolysis in the presence of rhamnose as donor and mannitol, fructose or esculin as acceptors. The effects of initial substrate concentrations, reaction time, and temperature on RCC yields were investigated in detail when using mannitol as the acceptor. The mannitol derivative achieved a maximal yield of 36.1% by incubation of the enzyme with 0.4 M L-rhamnose and 0.2 M mannitol in pH 6.5 buffers at 55°C for 48 h. In identical conditions except for the initial acceptor concentrations, the maximal yields of fructose and esculin derivatives reached 11.9% and 17.9% respectively. The structures of the three derivatives were identified to be α-L-rhamnopyranosyl-(1→6')-D-mannitol, α-L-rhamnopyranosyl-(1→1')-β-D-fructopyranose, and 6,7-dihydroxycoumarin α-L-rhamnopyranosyl-(1→6')-β-D-glucopyranoside by ESI-MS and NMR spectroscopy. The high glycosylation efficiency as well as the broad acceptor specificity of this enzyme makes it a powerful tool for the synthesis of novel rhamnosyl glycosides.

Malva verticillata seed extracts upregulate the Wnt pathway in human dermal papilla cells

OBJECTIVE

Mesenchymal-epithelial interactions are important in controlling hair growth and the hair cycle. The β-catenin pathway of dermal papilla cells (DPCs) plays a pivotal role in morphogenesis and normal regeneration of hair follicles. Deletion of β-catenin in the dermal papilla reduces proliferation of the hair follicle progenitor cells that generate the hair shaft and induces an early onset of the catagen phase. In this study, a modulator of the Wnt/β-catenin activity was studied in oriental herb extracts on cultured human DPCs.

METHODS

The effect of Malva verticillata (M. verticillata) seeds on human DPCs was investigated by a Wnt/β-catenin reporter activity assay system (β-catenin-TCF/LEF reporter gene) and cell proliferation analysis. The synthesis of the factors related to hair growth and cycling was measured at both the mRNA and the protein level by semi-quantitative PCR and Western blot analysis, respectively.

RESULTS

An extract from M. verticillata seeds increased Wnt reporter activity in a concentration-dependent manner and also led to increased β-catenin levels in cultured human DPCs. Myristoleic acid, identified as an effective compound of M. verticillata seeds, stimulated the proliferation of DPCs in a dose-dependent manner and increased transcription levels of the downstream targets: IGF-1, KGF, VEGF and HGF. Myristoleic acid also enhanced the phosphorylation of MAPKs (Akt and p38).

CONCLUSION

Overall, the data suggest that this extract of M. verticillata seeds could be a good candidate for treating hair loss by modulating the Wnt/β-catenin pathway in DPCs.

Chemical composition, antioxidant and antibacterial properties of Pteranthus dichotomus from Algerian Sahara

The phytochemical study of ethyl acetate and n-butanol extracts of Pteranthus dichotomus Forssk. led to the isolation and identification of 11 compounds, including three glycolipids 1-3, one lignan 4, three flavonoids 5-7 and four phytosterols 8-11. Structures of the isolated compounds have been elucidated by analysis of 1D and 2D NMR data, and mass spectrometry EI-MS and ESI-MS and by comparison with literature data. Furthermore, the ethyl acetate and n-butanol extracts were examined for their antioxidant and antibacterial activities. The results showed that both extracts (PDAC and PDBU) had a moderate antioxidant activity (IC50 = 375.514 μg/mL and 691.333 μg/mL) respectively.

Chemical profiling (HPLC-NMR & HPLC-MS), isolation, and identification of bioactive meroditerpenoids from the southern Australian marine brown alga Sargassum paradoxum

A phytochemical investigation of a southern Australian marine brown alga, Sargassum paradoxum, resulted in the isolation and identification of four new (5, 9, 10, and 15) and nine previously reported (1, 2, 6-8, and 11-14) bioactive meroditerpenoids. HPLC-NMR and HPLC-MS were central to the identification of a new unstable compound, sargahydroquinal (9), and pivotal in the deconvolution of eight (1, 2, 5-7, and 10-12) other meroditerpenoids. In particular, the complete characterization and identification of the two main constituents (1 and 2) in the crude dichloromethane extract was achieved using stop-flow HPLC-NMR and HPLC-MS. This study resulted in the first acquisition of gHMBCAD NMR spectra in the stop-flow HPLC-NMR mode for a system solely equipped with a 60 μL HPLC-NMR flow cell without the use of a cold probe, microcoil, or any pre-concentration.

Antitumor activity of kielmeyera coriacea leaf constituents in experimental melanoma, tested in vitro and in vivo in syngeneic mice

PURPOSE

The antitumor activity of Kielmeyera coriacea (Clusiaceae), a medicinal plant used in the treatment of parasitic, as well as fungal and bacterial infections by the Brazilian Cerrado population, was investigated.

METHODS

A chloroform extract (CE) of K. coriacea was tested in the murine melanoma cell line (B16F10-Nex2) and a panel of human tumor cell lines. Tumor cell migration was determined by the wound-healing assay and the in vivo antitumor activity of CE was investigated in a melanoma cell metastatic model. 1H NMR and GC/MS were used to determine CE chemical composition.

RESULTS

We found that CE exhibited strong cytotoxic activity against murine melanoma cells and a panel of human tumor cell lines in vitro. CE also inhibited growth of B16F10-Nex2 cells at sub lethal concentrations, inducing cell cycle arrest at S phase, and inhibition of tumor cell migration. Most importantly, administration of CE significantly reduced the number of melanoma metastatic nodules in vivo. Chemical analysis of CE indicated the presence of the long chain fatty compounds, 1-eicosanol, 1-docosanol, and 2-nonadecanone as main constituents.

CONCLUSION

These results indicate that K. coriacea is a promising medicinal plant in cancer therapy exhibiting antitumor activity both in vitro and in vivo against different tumor cell lines.

In vitro evaluation of the antioxidant and cytotoxic activities of constituents of the mangrove Lumnitzera racemosa Willd

This study performed phytochemical and bioactive assessments of the mangrove Lumnitzera racemosa Willd. leaves. Bioassay-guided fractionation of the methanolic extracts led to the identification of thirty-six compounds (1-36), their structures were elucidated using detailed NMR spectroscopic and MS analysis. The extracts, fractions, and the isolated compounds were screened for potential antioxidant and cytotoxic activities. Antioxidant assays were performed using peroxyl radical-scavenging and reducing assays, whereas cytotoxicity was measured using MTT assays in HL-60 and Hel-299 cell lines. The methanolic extract, CH2Cl2 and n-BuOH fractions (10.0 μg/mL) exhibited potent antioxidant activity, with Trolox equivalent (TE) values of 24.94 ± 0.59, 28.34 ± 0.20, and 27.09 ± 0.37 (μM), respectively. In addition, the isolated compounds exerted cytotoxic effects in a dose-dependent manner; compounds 1 and 14 exhibited the most potent cytotoxicity in HL-60 cells, with IC50 values of 0.15 ± 0.29 and 0.60 ± 0.16 μM, respectively. To clarify the mechanism(s) behind these cytotoxic effects, we measured the time-dependent changes in apoptotic markers including the condensation and fragmentation of nuclear chromatin, and the downregulation of p-ERK1/2, p-AKT, and c-Myc levels.

Minor Ent-abietane Diterpenoids from Euphorbia guyoniana

Three new abietane-type diterpenoids: ent-abieta-8,11,13-trien-16-ol (1), ent-abieta-8,11,13-trien-11,16-diol (2) and 11,12-dihydroxy-7-oxo- ent-abieta-8,11,13-trien-16-oic acid methyl ester (3), in addition to three known triterpenoids: euphol (4), 24,25-epoxycycloartanol (5) and β-sitosterol O-β-D-glucoside (6) were isolated from the chloroform extract of the roots of Euphorbia guyoniana. Structures of the isolated compounds were established on the basis of spectroscopic analyses, including 1D and 2D homo and heteronuclear NMR experiments and ESIMS, and comparison with literature data.

Non-toxic melanin production inhibitors from Garcinia livingstonei (Clusiaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

The stem bark of Garcinia livingstonei is used traditionally as a skin lightening agent.

AIM OF THE STUDY

To isolate and identify compounds responsible for the observed skin lightening activity of Garcinia livingstonei and to evaluate their cytotoxicity.

MATERIALS AND METHODS

Constituents of the stem bark and fruits of Garcinia livingstonei were isolated using chromatographic techniques and structures were determined using 1D and 2D NMR and MS analysis. MeWo cells were used to evaluate the cytotoxicity and impact on melanin levels of extracts and compounds isolated, in vitro.

RESULTS

Twelve known compounds, morelloflavone (1), morelloflavone-7″-sulphate (2), guttiferone A (3), sargaol (4), isojacareubin (5), 6-deoxyisojacareubin (6) and in addition to the common triterpenoids, betulin, betulin aldehyde, lupeol, lupenone, euphol and stigmasterol were isolated in this investigation. Morelloflavone, morelloflavone-7″-sulphate and sargaol, were found to be considerably less cytotoxic and more effective as skin lightening agents than hydroquinone.

CONCLUSIONS

A range of compounds was isolated from the stem bark and fruit of Garcinia livingstonei. Although the bark extract contained the cytotoxic guttiferone A, it was found to be less toxic than hydroquinone, and morelloflavone, the 7″-sulphate derivative and sargaol show potential for development as depigmentation/skin lightening agents.

Alliumonoate: a new cyclopentane derivative from Allium victorialis

Alliumonoate, a new cyclopentane derivative, has been isolated from the chloroform-soluble fraction of the ethanolic extract of Allium victorialis, along with β-amyrin acetate, β-sitosterol acetate, 22-cyclohexyl-1-docosanol, β-amyrin, β-sitosterol, and β-sitosterol 3-O-β-D-glucopyranoside, reported for the first time from this species. Their structures were elucidated on the basis of spectral data including mass spectra and 2D NMR experiments.

A New Rearranged Abietane Diterpene and other Constituents from Clerodendrum Philipinum

From the methanolic extract of the roots of Clerodendrum philipinum, a new rearranged abietane diterpene (1) and eight known compounds were isolated by various chromatography methods. Their structures were identified by means of spectroscopic methods, including 1D- and 2D-NMR, as 17(15→16),18(4→3)-bisabeo-11,12,14,16-tetrahydroxy-3,5,8,11, 13, 15-abietahexaen-7-one (1), binankadsurin A, clerodenoside A, martynoside, acteoside, isoacteoside, astragalin, β-sitosterol, and daucosterol. Binankadsurin A was found for the first time from a Clerodendrum species.

A novel daucosterol derivative and antibacterial activity of compounds fromArctotis arctotoides

Arctotis arctotoides is a perennial herb used medicinally for the treatment of various ailments in the Eastern Cape, South Africa. Different extracts of the plant were investigated for their antimicrobial constituents. This led to the isolation and identification of a new daucosterol derivative 3-O-[beta-D-(6'-nonadeanoate)glucopyranosyl]-beta-sitosterol and seven known compounds namely: serratagenic acid, stigmasterol, daucosterol, zaluzanin D, dehydrocostuslactone, nepetin, and pedalitin. The structures of the compounds were elucidated on the basis of spectral analysis, including homo and hetero nuclear correlation NMR experiments (COSY, NOESY, HMQC, HMBC) and mass spectra as well as by comparison with available data in the literature. The compounds exhibited antibacterial activity except stigmasterol, daucosterol and dehydrocostuslactone. Nepetin was the most active against Bacillus subtilis and Staphylococcus aureus with the minimum inhibitory concentrations of 4 microg mL( - 1) and 31 microg mL( - 1), respectively, while others exhibited moderate activity.

Marine polyprenylated hydroquinones, quinones, and chromenols with inhibitory effects on leukotriene formation

A series of polyprenylated hydroquinones, quinones, and chromenols were isolated from the extracts of the marine sponge Ircinia spinosula and the brown alga Taonia atomaria, which gave rise to the constituents 1-4 and 5-8, respectively. Compounds 1, 2, 6, and 7 are new natural products, which were fully characterized. Their anti-inflammatory activities in terms of leukotriene formation were evaluated in an in vitro assay with pork leukocytes. The new hydroxylated compound, 2'-[28-hydroxy]heptaprenyl-1',4'-hydroquinone (= 2-[(2E,6E,10E,14E,18Z,22E)-19-(hydroxymethyl)-3,7,11,15,23,27-hexamethyloctacosa-2,6,10,14,18,22,26-heptaen-1-yl]benzene-1,4-diol; 1), the known tetraprenyl benzoquinone sargaquinone (5), and the known polyprenyl chromenols 3 and 4 exhibited the highest anti-inflammatory activities, with IC50 values of 1.9-9.4 microM (Table 3). Potential structure-activity relationships (SAR) are discussed.

Antielastase and free radical scavenging activities of compounds from the stems ofCornus kousa

Bioassay-guided investigation of the stems of Cornus kousa led to the isolation of 12 compounds such as four triterpenoids: betulinic acid (1), maslinic acid (2), arjunolic acid (3), 3-isoarjunolic acid (4), four flavanoids; catechin (5), epi-catechin (6), 2-hydroxynaringenin (7), 2-hydroxynaringenin-7-O-beta-D-glucopyranoside (8), two ellagic acid derivatives; 3,4,3'-tri-O-methylellagic acid (9), 3,4-di-O-methylellagic acid (10), a daucosterol (11) and a sucrose derivative; (3'-O-p-coumaroyl)-beta-D-fructofuranosy-(2?1)-(6-O-p-coumaroyl)-alpha-D-glucopyranoside (12). Their structures were elucidated on the basis of spectroscopic studies as well as by comparison with available data in the literature. The free radical scavenging activity and elastase inhibition activity were investigated for the development of antiaging ingredients as a raw material for use in cosmetics. Among these compounds, compounds 1, 2 and 8 showed significant elastase inhibition activity and IC(50) was 10.81 microg/mL, 21.21 microg/mL and 44.63 microg/mL, respectively, on porcine pancreatic elastase, whereas compounds 5, 6, 7 and 8 showed significant free radical scavenging activity and SC(50) was 8.37 microg/mL, 9.31 microg/mL, 9.23 microg/mL and 17.45 microg/mL, respectively.

Medicinal Flowers. XII.1) New Spirostane-Type Steroid Saponins with Antidiabetogenic Activity from Borassus flabellifer

The methanolic extract from the male flowers of Borassus flabellifer was found to inhibit the increase of serum glucose levels in sucrose-loaded rats at a dose of 250 mg/kg, p.o. From the methanolic extract, six new spirostane-type steroid saponins, borassosides A-F (1-6), were isolated together with 23 known constituents. The structures of borassosides (1-6) were elucidated on the basis of chemical and physicochemical evidences. In addition, the principal steroid saponin, dioscin (13), inhibited the increase of serum glucose levels in sucrose-loaded rats at a dose of 50 mg/kg, p.o.

Structures of New Flavonoids, Erycibenins D, E, and F, and NO Production Inhibitors from Erycibe expansa Originating in Thailand

A new flavanol, erycibenin D, and two new flavans, erycibenins E and F, were isolated from the stems of Erycibe expansa originating in Thailand. The structures of new flavonoids were elucidated on the basis of chemical and physicochemical evidence. In addition, the inhibitory activities of the isolated constituents from E. expansa on lipopolysaccharide-activated nitric oxide production in mouse peritoneal macrophages were examined. Among the principal constituents, two isoflavones, clycosin (IC50 = 13 microM) and erythrinin B (18 microM), and two rotenoids, deguelin (26 microM) and rotenone (27 microM), were found to show potent inhibitory activity.

New ether diglycosides from Matayba guianensis with antiplasmodial activity

Four new ether diglycosides (1-4), named matayosides A-D, were isolated from the root bark of Matayba guianensis, a plant exhibiting in vitro antiplasmodial activity. They were identified as hexadecyl-[O-2,3,4-tri-O-acetyl-alpha-L-rhamnopyranosyl-(1-->2)]-6-O-palmitoyl-beta-D-glucopyranoside, hexadecyl-[O-2,3,4-tri-O-acetyl-alpha-L-rhamnopyranosyl-(1-->2)]-4,6-di-O-acetyl-beta-D-glucopyranoside, hexadecyl-[O-2,3,4-tri-O-acetyl-alpha-L-rhamnopyranosyl-(1-->2)]-3,6-di-O-acetyl-beta-D-glucopyranoside and hexadecyl-[O-2,3,4-tri-O-acetyl-alpha-L-rhamnopyranosyl-(1-->2)]-6-O-acetyl-beta-D-glucopyranoside, respectively. Their structures were established using one- and two-dimensional NMR techniques, mass spectrometry (MS) and MS/MS experiments. The compounds were found to inhibit the growth of Plasmodium falciparum in vitro with IC50 values ranging from 2.5 to 8.9 microg/mL.

Astonishing diversity of natural surfactants: 4. Fatty acid amide glycosides, their analogs and derivatives

FA amide glycosides are of great interest, especially for the medicinal and pharmaceutical industries. These biologically active natural surfactants are good prospects for future chemical preparation of compounds useful as antibiotics, anticancer agents, or for industry. More than 200 unusual and interesting natural surfactants, including their chemical structures and biological activities, are described in this review article.