Bioguided chemical study of Hutch. (Burseraceae) for antibacterial agents and a new glucopyranoxylmethoxybenzyle.

Stem barks of are used traditionally for the treatment of various bacterial infections. A bioassay guided fractionation of the MeOH-CHCl (1/1, v/v) stem barks extract led to the isolation of fourteen compounds , identified based on spectroscopic data. Dalzienoside ( is reported here for the first time.

Screening of the Pan-African natural product library identifies ixoratannin A-2 and boldine as novel HIV-1 inhibitors.

The continued burden of HIV in resource-limited regions such as parts of sub-Saharan Africa, combined with adverse effects and potential risks of resistance to existing antiretroviral therapies, emphasize the need to identify new HIV inhibitors. Here we performed a virtual screen of molecules from the pan-African Natural Product Library, the largest collection of medicinal plant-derived pure compounds on the African continent. We identified eight molecules with structural similarity to reported interactors of Vpu, an HIV-1 accessory protein with reported ion channel activity.

Elatumic acid: a new ursolic acid congener from Omphalocarpum elatum Miers (Sapotaceae).

A new triterpene diastereomer, 1, of the previously reported 3beta,6beta,19alpha-trihydroxy-urs-12-en-28-oic acid-24-carboxylic acid methyl ester was obtained from the stem bark of Omphalocarpum elatum Miers (Sapotaceae) along with a-amyrin acetate (2), spinasterol (3), spinasterol 3-O-beta-D-glucopyranoside (4), and tormentic acid (5). The structures of the isolates were established on the basis of NMR and mass spectrometric data and by comparison with those previously reported in the literature. Compound 1 showed weak antibacterial activity against E.

Excelsoside: a new benzylic diglycoside from the leaves of Milicia excelsa.

A new benzylic diglycoside was isolated from the leaves of Milicia excelsa and identified as 3,4-dimethoxybenzyl beta-D-xylopyranosyl (1 --> 2)-beta-D-glucopyranoside (1). It was obtained together with four known secondary metabolites including lupeol acetate (2), ursolic acid (3), triacontyl (E)-ferulate (4), and 2-(3,5-dihydroxyphenyl)benzofuran-5,6-diol (5). Their structures were determined based on their spectroscopic data and by comparison with those reported in the literature.

Antiproliferative activity of the isofuranonaphthoquinone isolated from Bulbine frutescens against Jurkat T cells.

Cancer is a major public health burden in both developed and developing countries. The quinone moiety has been shown to possess antitumor activity and several cancer drugs in clinical use contain this entity. The effect of isofuranonaphthoquinone isolated from Bulbine frutescens on Jurkat T cells was determined.

Cytotoxicity of semisynthetic acetal triterpenes from one-pot vicinal diol cleavage following by lactolization: reaction promoted by NaIO4/SiO2 gel in THF.

In situ C-C bond cleavage of vicinal diol following by the lactolisation resulted from separated treatment of Arjunolic acid (1), 24-hydroxytormentic acid (2) and 3-O-β-D-glucopyranosylsitosterol (3) with sodium periodate and silica gel in dried THF according to the strategic position of hydroxyl functions in the molecule. The reaction led to a lactol pentacyclic triterpenes 1A, 2A and a bicyclotriacetal of β-sitosterol 3A. These products were further acetylated and the cytotoxicity of all molecules was evaluated against human fibrosarcoma HT1080 cancer cells lines.

A new approach for anthelmintic discovery for humans.

Natural product-based drug discovery has been deemphasized by the pharmaceutical industry. This situation is discordant with the fact that most people in developing countries rely on traditional medicines derived from local biodiversity for healthcare. Despite economic growth in the past 10 years, Africa remains plagued by parasitic infections, out of reach of eradication.

Old plants newly discovered: Cassia sieberiana D.C. and Cassia abbreviata Oliv. Oliv. root extracts inhibit in vitro HIV-1c replication in peripheral blood mononuclear cells (PBMCs) by different modes of action.

Ethnopharmacological Relevance: Despite advances in anti-retroviral therapy which has transformed HIV/AIDS from a fatal to a manageable chronic disease, increasing viral drug resistance, side effects and uneven access to anti-retroviral drugs remain considerable therapeutic challenges. Partly as a consequence of these shortcomings and partly based on the fact that HIV/AIDS gives rise to opportunistic infections whose symptoms have been managed in Africa in an HIV/AIDS-independent context by traditional healers for centuries, many HIV/AIDS patients use herbal medicines. The aim of this study was to screen selected medicinal plants from Botswana, used by traditional healers to treat/manage HIV/AIDS, for inhibitory activities on HIV replication.

Phosphodiesterase I-inhibiting Diels-Alder adducts from the leaves of Morus mesozygia.

A new 2-arylbenzofuran derivative, (+)-dimethylsmoracin O (1), and three new Diels-Alder type adducts, mesozygins A–C (2–4), in addition to eight known compounds, artonin I (5), chalcomaracin (6), norartocarpetin (7), moracin L (8), mulberrofuran F (9), moracin M (10), moracin C (11), and morachalcone A (12),were isolated from the leaves of Morus mesozygia Stapf. Structures were elucidated by spectroscopic data analyses. Compounds 2-7 displayed a potent phosphodiesterase I inhibitory activity.

Antimicrobial activities of the methanol extract and compounds from Artocarpus communis (Moraceae).

Background: Artocarpus communis is used traditionally in Cameroon to treat several ailments, including infectious and associated diseases. This work was therefore designed to investigate the antimicrobial activities of the methanol extract (ACB) and compounds isolated from the bark of this plant, namely peruvianursenyl acetate C (1), α-amyrenol or viminalol (2), artonin E (4) and 2-[(3,5-dihydroxy)-(Z)-4-(3-methylbut-1-enyl)phenyl]benzofuran-6-ol (5).

Methods: The liquid microdilution assay was used in the determination of the minimal inhibitory concentration (MIC) and the minimal microbicidal concentration (MMC), against seven bacterial and one fungal species.

Hepatoprotective and antioxidant arylbenzofurans and flavonoids from the twigs of Morus mesozygia.

The chemical investigation of the twigs of Morus mesozygia resulted in the isolation of three new prenylated 2-arylbenzofurans, named moracin KM, LM, and SC (1-3), nine known 2-arylbenzofurans (4-12), and two known flavonoids (13-14). The structures of the new compounds were established as [2'',3'':6,7]-(6-(S)-hydroxymethyl-6-methylpyrano)-2-(3,5-dihydroxyphenyl)benzofuran-5-ol (1), [2'',3'':6,7]-(4,7-dihydro-6-methyloxepine)-2-(3-hydroxy-5-methoxyphenyl)benzofuran-5-ol (2), and [2'',3'':6,7]-(6,6-dimethylpyrano)-2-(3,5-dihydroxyphenyl)benzofuran (3). One of the new compounds, moracin LM (2), displayed modest antioxidant activity, whereas known compounds 4, 13, and 14 showed significant hepatoprotective and antioxidant activities.

Terpenoids from Turraeanthus species.

Chemical investigation of the root bark of Turraeanthus mannii and the stem of T. longipes resulted in the isolation of two new diterpenes, 13-methyl-labda-8(17)-en-15-oic acid (1) and 13-(hydroxymethyl)-14-hydroxy-ent-labda-8(17)-en-15-oic acid (2), along with two known diterpenes, 19-hydroxy-ent-labda-8(17),13-dien-15,16-olide (3) and 19-acetoxy-ent-labda-8(17),13-dien-15,16-olide (4), and the phytosterol, stigmasterol. The structure elucidation of the new compounds has been achieved using spectroscopic techniques.

Duboscic acid: a potent α-glucosidase inhibitor with an unprecedented triterpenoidal carbon skeleton from Duboscia macrocarpa.

Duboscic acid (1), a triterpenoid with a unique carbon backbone, was isolated from Duboscia macrocarpa Bocq. It is the first member of a new class of triterpenoids, for which the name "dubosane" is proposed. Duboscic acid has a potent α-glucosidase inhibition, and its structure was unambiguously deduced by a single-crystal X-ray diffraction study.

The evaluation of novel natural products as inhibitors of human glutathione transferase P1-1.

Glutathione transferase P1-1 is over expressed in some cancer cells and contributes to detoxification of anticancer drugs, leading to drug-resistant tumors. The inhibition of human recombinant GSTP1-1 by natural plant products was investigated using 10 compounds isolated from plants indigenous to Southern and Central Africa. Monochlorobimane and 1-chloro-2,4-dinitrobenzene were used to determine GST activity.

Doubly linked, A-type proanthocyanidin trimer and other constituents of Ixora coccinea leaves and their antioxidant and antibacterial properties.

Phytochemical investigation of the ethyl acetate fraction of the methanol extract of the leaves of Ixora coccinea led to the isolation and identification of an A-type trimeric proanthocyanidin epicatechin-(2β→O→7, 4β→8)-epicatechin-(5→O→2β, 6→4β)-epicatechin named ixoratannin A-2 along with seven known compounds, epicatechin, procyanidin A2, cinnamtannin B-1, and four flavon-3-ol rhamnosides viz: kaempferol-7-O-α-L-rhamnnoside, kaempferol-3-O-α-L-rhamnoside, quercetin-3-O-α-L-rhamnopyranoside, and kaempferol-3,7-O-α-L-dirhamnoside. The structures were elucidated by the application of IR, UV, MS, 1D-, and 2D-NMR spectroscopic analyses and by comparison with literature data. Antioxidant evaluation of isolated compounds revealed that ixoratannin A-2 and cinnamtannin B-1 were the most active compounds in DPPH, inhibition of lipid peroxidation and nitric oxide radical scavenging assays.

Glutathione transferase from Plasmodium falciparum--interaction with malagashanine and selected plant natural products.

A glutathione transferase (PfGST) isolated from Plasmodium falciparum has been associated with chloroquine resistance. A range of natural products including malagashanine (MG) were screened for inhibition of PfGST by a GST assay with 1-chloro-2,4-dinitrobenzene as a substrate. Only the sesquiterpene (JBC 42C), the bicoumarin (Tral-1), ellagic acid and curcumin, were shown to be potent inhibitors of PfGST with IC(50) values of 8.

A new bianthracene C-arabinopyranoside from Senna septemtrionalis.

Chrysophanol, physcion, emodin, floribundone-1, 5,7'-physcion-fallacinol, and the novel 5,7'-physcion-physcion-10'-C-alpha-arabinopyranoside were isolated from the stem bark of Senna septemtrionalis. The structures of these secondary metabolites were determined on the basis of spectroscopic analysis, especially from NMR spectra in conjunction with COSY, HMQC, HMBC and TOCSY.

Total synthesis, antiprotozoal and cytotoxicity activities of rhuschalcone VI and analogs.

The total synthesis of a potent antiplasmodial natural bichalcone, rhuschalcone VI, is described starting from simple and available resorcinol and 4-hydroxybenzaldehyde. Key steps include the solvent-free Aldol syntheses of chalcones, and the successful application of the Suzuki-Miyaura coupling reaction in the synthesis of bichalcones. The present work constitutes a general method for the rapid syntheses of a number of bichalcones related to rhuschalcone VI.

HPLC analysis and NMR identification of homoisoflavonoids and stilbenoids from the inter-bulb surfaces of Scilla nervosa.

The yellow inter-bulb deposits from Scilla nervosa were analyzed by HPLC and found to contain 19 major components. Twelve of the 19 were identified by comparison of R(t) values with those of authentic homoisoflavonoids and stilbenoids, co-elution and by preparative isolation followed by NMR and MS analyses. Of these, two homoisoflavonoids, 3-(4-hydroxyoxybenzyl)-5,7-dimethoxy-6-hydroxychroman-4-one and 3-(4-methoxybenzyl)-6,7-dimethoxy-5-hydroxychroman-4-one are new.

Prenylated arylbenzofuran derivatives from Morus mesozygia with antioxidant activity.

Five prenylated arylbenzofurans, moracins Q-U, were isolated from Morus mesozygia (Moraceae). Their structures were elucidated on the basis of spectroscopic evidence. Along with these compounds, 3beta-acetoxyurs-12-en-11-one, marsformoxide, moracin C, moracin M, moracin K, artocarpesin, cycloartocarpesin, morachalcone A were also isolated.

Knipholone and related 4-phenylanthraquinones: structurally, pharmacologically, and biosynthetically remarkable natural products.

This review gives the first comprehensive overview of the rapidly emerging young class of 4-phenylanthraquinones isolated from the three genera Bulbine, Bulbinella, and Kniphofia, all from the plant family Aphodelaceae: their occurrence, structural elucidation (with particular emphasis on the phenomenon of axial chirality), partial and total synthesis, their pharmacological (i.a., antimalarial and antitumoral) activities, and their biosynthetic origin (from acetate units).

Modulation of Anopheles gambiae Epsilon glutathione transferase activity by plant natural products in vitro.

Elevated glutathione transferase (GST) E2 activity is associated with DDT resistance in the mosquito Anopheles gambiae. The search for chemomodulators that inhibit the function of AgGSTE2 would enhance the insecticidal activity of DDT. Therefore, we examined the interaction of novel natural plant products with heterologously expressed An.