Evaluation of the mechanism of action of albendazole on adult rat lungworm (Angiostrongyluscantonensis).

Albendazole is considered the anthelmintic of choice for the management of rat lungworm disease (neuroangiostrongyliasis), due to its broad spectrum of nematocidal activity and its ability to cross the blood-brain barrier. Albendazole binds to ß-tubulins, preventing their polymerization into microtubules, thereby corrupting the cascade of cell division at metaphase, which ultimately leads to the death of individual cells and eventually the death of the parasite. Inhibition of microtubule formation will also hinder the axoplasmic transport system, affecting the neuronal activities of the parasite. While this mechanism has been explicated in other parasitic and non-parasitic nematodes, it has never been evaluated in Angiostrongylus cantonensis. This study evaluates the antimitotic effects of albendazole sulphoxide (active metabolite) on the microtubules of adult A. cantonensis using the tubulin polymerization assay and measures its effects on worm viability using the colorimetric MTT assay. Three different concentrations of albendazole (62.5 µM, 250 µΜ, and 1 mM) were evaluated. We saw a statistically significant dose-dependent reduction in the band intensity of polymerized tubulins (or microtubules) (P = 0.019), suggesting that albendazole imparts its antimitotic effect in a dose-dependent manner. Similarly, our MTT assay showed a dose-dependent decrease in formazan intensity (proportional to cell viability), suggesting that the rate of nematocidal activity of albendazole is also proportional to its concentration. In compiling the results from both these experiments, a correlation between the microtubule assembly and worm viability is evident.

Simple derivation of skeletal muscle from human pluripotent stem cells using temperature-sensitive Sendai virus vector.

Human pluripotent stem cells have the potential to differentiate into various cell types including skeletal muscles (SkM), and they are applied to regenerative medicine or in vitro modelling for intractable diseases. A simple differentiation method is required for SkM cells to accelerate neuromuscular disease studies. Here, we established a simple method to convert human pluripotent stem cells into SkM cells by using temperature-sensitive Sendai virus (SeV) vector encoding myoblast determination protein 1 (SeV-Myod1), a myogenic master transcription factor. SeV-Myod1 treatment converted human embryonic stem cells (ESCs) into SkM cells, which expressed SkM markers including myosin heavy chain (MHC). We then removed the SeV vector by temporal treatment at a high temperature of 38℃, which also accelerated mesodermal differentiation, and found that SkM cells exhibited fibre-like morphology. Finally, after removal of the residual human ESCs by pluripotent stem cell-targeting delivery of cytotoxic compound, we generated SkM cells with 80% MHC positivity and responsiveness to electrical stimulation. This simple method for myogenic differentiation was applicable to human-induced pluripotent stem cells and will be beneficial for investigations of disease mechanisms and drug discovery in the future.

In vitro efficacy of anthelmintics on Angiostrongylus cantonensis L3 larvae.

Angiostrongylus cantonensis is the leading cause of eosinophilic meningitis worldwide, with life-threatening complications if not managed correctly. Previous in vitro studies have utilized change in motility patterns of adult female worms to assess the efficacy of anthelmintics qualitatively. However, it is the third stage larvae (L3) that are infectious to humans. With differential staining using propidium iodide penetration as the indicator of death, we can distinguish between dead and live larvae. This assay has enabled us to quantify the in vitro efficacy of nine clinically established anthelmintics on A. cantonensis L3. All drugs were tested at a 1 mm concentration. Piperazine and niclosamide were ineffective in inducing larval death; however, albendazole sulfoxide, pyrantel pamoate, diethylcarbamazine, levamisole and praziquantel were effective as compared to unexposed controls (P < 0.05). Ivermectin and moxidectin did not induce significant levels of mortality, but they considerably reduced larval motility almost immediately. This study indicates the need for further in vivo studies to determine the optimal dose and time frame for post-infection treatment with anthelmintics that demonstrated efficacy.

Molecular Docking and Molecular Dynamics Simulation Studies of Triterpenes from Vernonia patula with the Cannabinoid Type 1 Receptor.

A molecular docking approach was employed to evaluate the binding affinity of six triterpenes, namely epifriedelanol, friedelin, α-amyrin, α-amyrin acetate, ß-amyrin acetate, and bauerenyl acetate, towards the cannabinoid type 1 receptor (CB1). Molecular docking studies showed that friedelin, α-amyrin, and epifriedelanol had the strongest binding affinity towards CB1. Molecular dynamics simulation studies revealed that friedelin and α-amyrin engaged in stable non-bonding interactions by binding to a pocket close to the active site on the surface of the CB1 target protein. The studied triterpenes showed a good capacity to penetrate the blood-brain barrier. These results help to provide some evidence to justify, at least in part, the previously reported antinociceptive and sedative properties of Vernonia patula.

Engineering the AAVS1 locus for consistent and scalable transgene expression in human iPSCs and their differentiated derivatives.

The potential use of induced pluripotent stem cells (iPSCs) in personalized regenerative medicine applications may be augmented by transgenics, including the expression of constitutive cell labels, differentiation reporters, or modulators of disease phenotypes. Thus, there is precedence for reproducible transgene expression amongst iPSC sub-clones with isogenic or diverse genetic backgrounds. Using virus or transposon vectors, transgene integration sites and copy numbers are difficult to control, and nearly impossible to reproduce across multiple cell lines. Moreover, randomly integrated transgenes are often subject to pleiotropic position effects as a consequence of epigenetic changes inherent in differentiation, undermining applications in iPSCs. To address this, we have adapted popular TALEN and CRISPR/Cas9 nuclease technologies in order to introduce transgenes into pre-defined loci and overcome random position effects. AAVS1 is an exemplary locus within the PPP1R12C gene that permits robust expression of CAG promoter-driven transgenes. Gene targeting controls transgene copy number such that reporter expression patterns are reproducible and scalable by ∼2-fold. Furthermore, gene expression is maintained during long-term human iPSC culture and in vitro differentiation along multiple lineages. Here, we outline our AAVS1 targeting protocol using standardized donor vectors and construction methods, as well as provide practical considerations for iPSC culture, drug selection, and genotyping.

Solid-phase synthesis of cyclic hexapeptides wollamides A, B and desotamide B.

Solid-phase synthesis of antibacterial cyclohexapeptides including wollamides A, B and desotamide B has been developed. Briefly, the protected linear hexapeptides were assembled on 2-chlorotrityl chloride resin using standard Fmoc chemistry and diisopropylcarbodiimide/hydroxybenzotriazole coupling reagents, cleaved off-resin with hexafluoroisopropanol/dichloromethane to keep side-chain protecting groups intact, and cyclized in solution. Final global removal of all protecting groups using a cocktail of trifluoroacetic acid/triisopropylsilane/dichloromethane afforded the desired cyclic hexapeptides, which were characterized by 1H, 13C NMR, and HRMS. Subsequent investigation of macrocyclization parameters such as terminal residues, coupling reagents, and cyclization concentration revealed the optimized conditions for the synthesis of this class of cyclic hexapeptides.

Bioactive compounds from Vitex leptobotrys.

A new lignan, vitexkarinol (1), as well as a known lignan, neopaulownin (2), a known chalcone, 3-(4-hydroxyphenyl)-1-(2,4,6-trimethoxyphenyl)-2-propen-1-one (3), two known dehydroflavones, tsugafolin (4) and alpinetin (5), two known dipeptides, aurantiamide and aurantiamide acetate, a known sesquiterpene, vemopolyanthofuran, and five known carotenoid metabolites, vomifoliol, dihydrovomifoliol, dehydrovomifoliol, loliolide, and isololiolide, were isolated from the leaves and twigs of Vitex leptobotrys through bioassay-guided fractionation. The chalcone (3) was found to inhibit HIV-1 replication by 77% at 15.9 µM, and the two dehydroflavones (4 and 5) showed weak anti-HIV activity with IC50 values of 118 and 130 µM, respectively, while being devoid of cytotoxicity at 150 µM. A chlorophyll-enriched fraction of V. leptobotrys, containing pheophorbide a, was found to inhibit the replication of HIV-1 by 80% at a concentration of 10 µg/mL. Compounds 1 and 3 were further selected to be evaluated against 21 viral targets available at NIAID (National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA).

Bioassay-Guided Isolation and Identification of Cytotoxic Compounds from Melaleuca quinquenervia Fruits.

The fruit extract of Melaleuca quinquenervia yielded a total of 19 compounds, including two novel spiro-biflavonoid enantiomers (1a and 1b) and a chalcone derivative (3). Their structures were determined through spectroscopic analysis. The enantiomers of the racemic mixture of compound 1 were successfully resolved into (+)-1 and (-)-1 using chiral-phase HPLC. Single-crystal X-ray diffraction analysis was also used to confirm the structure of 1. The enantiomeric configurations of 1 and 2 were determined through a comparison of the calculated and experimental electronic circular dichroism spectra. Compounds 2 (melanervin), 14 (methyl betulinate), 15 (3-O-acetylbetulinic acid), and 16 (pyracrenic acid) were found to be highly cytotoxic, with compound 16 showing superior growth inhibition of nonsmall cell lung cancer cells (A549 cells) (IC50 2.8 ± 0.1 µM) compared to cisplatin (IC50 3.3 ± 0.0 µM), a positive control chemotherapeutic drug. Both compound 16 and cisplatin were significantly more cytotoxic toward A549 lung cancer cells compared to nontumorigenic Vero E6 cells.

An ethnobotanical survey of medicinal plants of Laos toward the discovery of bioactive compounds as potential candidates for pharmaceutical development.

CONTEXT: An ethnobotany-based approach in the selection of raw plant materials to study was implemented. OBJECTIVE: To acquire raw plant materials using ethnobotanical field interviews as starting point to discover new bioactive compounds from medicinal plants of the Lao People's Democratic Republic. METHODS: Using semi-structured field interviews with healers in the Lao PDR, plant samples were collected, extracted, and bio-assayed to detect bioactivity against cancer, HIV/AIDS, TB, malaria. Plant species demonstrating activity were recollected and the extracts subjected to a bioassay-guided isolation protocol to isolate and identify the active compounds. RESULTS: Field interviews with 118 healers in 15 of 17 provinces of Lao PDR yielded 753 collections (573 species) with 955 plant samples. Of these 955, 50 extracts demonstrated activity in the anticancer, 10 in the anti-HIV, 30 in the anti-TB, and 52 in the antimalarial assay. Recollection of actives followed by bioassay-guided isolation processes yielded a series of new and known in vitro-active anticancer and antimalarial compounds from 5 species. DISCUSSION: Laos has a rich biodiversity, harboring an estimated 8000-11,000 species of plants. In a country highly dependent on traditional medicine for its primary health care, this rich plant diversity serves as a major source of their medication. CONCLUSIONS: Ethnobotanical survey has demonstrated the richness of plant-based traditional medicine of Lao PDR, taxonomically and therapeutically. Biological assays of extracts of half of the 955 samples followed by in-depth studies of a number of actives have yielded a series of new bioactive compounds against the diseases of cancer and malaria.

Altersolanol B, a fungal tetrahydroanthraquinone, inhibits the proliferation of estrogen receptor-expressing (ER+) human breast adenocarcinoma by modulating PI3K/AKT, p38/ERK MAPK and associated signaling pathways.

The present study focused on the apoptosis-inducing effects and cellular signal-modulating properties of altersolanol B (AB), a minor fungal tetrahydroanthraquinone (THAQ) metabolite, in the estrogen receptor positive (ER+) human breast adenocarcinoma cell line, MCF-7. AB demonstrated approximately 4-fold greater antiproliferative activity in ER+ MCF-7 cells (IC50 5.5 µM) compared to the ER-negative (triple-negative) MDA-MB-231 (IC50 21.3 µM). The viability of normal breast fibrocystic epithelial cells, MCF-10A, was unaffected. AB induced intrinsic apoptosis in MCF-7 cells; it triggered the activation of caspase 9 and poly (ADP-ribose) polymerase (PARP), upregulated the expression of pro-apoptotic Bax, and downregulated the expression of anti-apoptotic Bcl-2. AB induced cell cycle arrest at G0/G1, as indicated by the downregulation of key checkpoint proteins operating at the G0/G1 phase of the cell cycle (cyclin D1, CDK4 and CDK2). The observed increase in p21Waf1/Cip1 and p53 expression may facilitate cell cycle arrest, and the subsequent induction of apoptosis. AB lacked significant effects on intracellular ROS levels, while it down-regulated nuclear factor erythroid 2-related factor 2 (Nrf2), and the Nrf2-dependent antioxidant enzyme, heme oxygenase-1. The compound disrupted AKT signaling through the downregulation of phospho-AKT and phospho-FOXO1, and the upregulation of PTEN, a phosphatase and tumor suppressor that negatively regulates the PI3K/AKT pathway. AB also disrupted the phosphorylation of AKT-controlled eukaryotic translation initiation factor, 4E-BP1, and GSK-3ß, both of which are aberrantly regulated in human cancer. The AB-dependent downregulation of NF-κB was corroborated by the inhibition of TNFα-induced NF-κB activity as monitored in a luciferase reporter. The NF-κB inhibitory activity of AB was 3-fold more potent than that of the standard inhibitor, N-p-Tosyl-l-phenylalanine chloromethyl ketone. In addition to reducing the pro-survival effects of NF-кB, the inhibition of AKT phosphorylation by AB may also lead to FOXO1-mediated growth arrest and apoptosis. AB upregulated the expression of phospho-MKK4 and phospho-p38, and downregulated the expression of phospho-MEK1/2 and phospho-ERK1/2 indicating opposing effects on the two important oncogenic signaling cascades that are aberrantly activated in many cancers. AB disrupted both the AKT and ERK1/2 signaling pathways leading to apoptosis in ER+ MCF-7 cells through mitochondria-associated mechanisms coupled with the potent inhibition of NF-кB activation. The clinical limitations of multi-agent combination therapy that targets multiple pathways in cancer may potentially be circumvented by using a single molecule, such as AB, that inhibits both AKT and ERK1/2 signaling. Our preliminary study suggested that the THAQ pharmacophore, with its disrupted conjugated ring system and relative redox inactivity, may possess greater mechanistic advantage against ER+ breast cancer when compared to the fully conjugated ring systems of the anthraquinone that possess intrinsic redox activity and DNA interacting ability. This study supports the continued investigation of THAQs as lead molecules in anticancer drug discovery and development.

Antimalarial activity of Aspilia pruliseta, a medicinal plant from Uganda.

Aspilia pruliseta Schweinf. (Asteraceae) is a medicinal plant indigenous to Uganda and the neighboring countries of East Africa. It has been used extensively by the rural population for the treatment of fevers and malaria. During the antimalarial evaluation of this plant, four nontoxic diterpenes were isolated that possessed moderate activity against chloroquine-sensitive (D6) and chloroquine-resistant (W2) clones of Plasmodium falciparum, with IC(50) values ranging from 14 to 23 µM. These moderately active compounds included the previously undescribed diterpene, ENT-15 ß-senecioyloxy-16,17-epoxy-kauran-18-oic acid that demonstrated an IC(50) value of 23.4 µM against clone D6, but was devoid of activity against clone W2. Four additional diterpenes were obtained from the aerial parts of A. pruliseta, but these known compounds were essentially inactive. The moderate activities of select diterpenes of A. pruliseta could account collectively for the historical and enduring use of this plant in traditional African medicine.

Bioactive sulfated sesterterpene alkaloids and sesterterpene sulfates from the marine sponge Fasciospongia sp.

Two new sulfated sesterterpene alkaloids, 19-oxofasciospongine A (3) and fasciospongine C (4), and a new sesterterpene sulfate, 25-hydroxyhalisulfate 9 (5), along with two known sesterterpene sulfates, halisulfates 7 (6) and 9 (7), were isolated from an organic extract of the marine sponge Fasciospongia sp. The structures of the new compounds were established on the basis of one- and two-dimensional NMR spectroscopic studies as well as by HRESIMS analysis. Compounds 1-7 exhibited inhibitory activity against Streptomyces 85E in the hyphae-formation inhibition assay. Compounds 1, 2, and 4-7 were not cytotoxic when tested at 20 microg/mL with MCF-7, LNCaP, and LU cell lines. Only compound 3 demonstrated a moderate cytotoxic effect on the MCF-7 (IC(50) 13.4 microM), LNCaP (IC(50) 21.8 microM), and LU-1 cells (IC(50) 5.0 microM), respectively.

Study of antimalarial activity of chemical constituents from Diospyros quaesita.

Bioassay-directed fractionation led to the isolation of seven compounds from a sample of the dried leaves, twigs, and branches of Diospyros quaesita Thw. (Ebenaceae). One of the isolates, betulinic acid 3-caffeate (1), showed in vitro antimalarial activity against Plasmodium falciparum clones D(6) (chloroquine-sensitive) and W(2) (chloroquine-resistant) with IC(50) values of 1.40 and 0.98 microM, respectively. Evaluation of compound 1 in the human oral epidermoid (KB) cancer cell line revealed cytotoxicity at ED(50) of 4.0 microM. In an attempt to reduce the cytotoxicity of 1, the acetylated derivative 1a and betulinic acid (1b) were prepared. Of the seven isolates, diospyrosin (2) was determined to be a new neolignan. In addition to 1, other known compounds isolated in this study were pinoresinol, lariciresinol, N-benzoyl-L-phenylalaninol, scopoletin, and poriferast-5-en-3beta,7alpha-diol. The structure of 2 was elucidated based on spectroscopic data analysis including 1D- and 2D-NMR, and HR-ESI-MS.

Solid-Phase Synthesis and Antibacterial Activity of Cyclohexapeptide Wollamide B Analogs.

Herein we report the antibacterial structure-activity relationships of cyclic hexapeptide wollamide analogs derived from solid-phase library synthesis. Wollamide B, a cyclic hexapeptide natural product, has been previously found to have activity against Mycobacterium bovis. To further evaluate its antimycobacterial/antibacterial potential, 27 peptides including wollamides A/B, and desotamide B, were synthesized and subsequently tested against a panel of clinically significant bacterial pathogens. Biological evaluation revealed that the cyclic scaffold, amide functionality in position I, tryptophan residue in position V, and the original stereochemistry pattern of the core scaffold were key for antituberculosis and/or antibacterial activity. In addition, against M. tuberculosis and Gram-positive bacteria, residues in position II and/or VI greatly impacted antibacterial activity and selectivity. Wollamides A (3) and B (2) along with their corresponding II (l-Leu) analog 10 retained the most promising antituberculosis activity, with the lowest minimum inhibitory concentration (MIC) against virulent M. tuberculosis H37Rv (MIC = 1.56 µg/mL), as well as desirable selectivity indices (>100). Importantly, the antimicrobial activities of wollamides A and B do not result from disruption of the bacterial membrane, warranting further investigation into their mechanism of action.

Siamese Crocodile White Blood Cell Extract Inhibits Cell Proliferation and Promotes Autophagy in Multiple Cancer Cell Lines.

Cancer represents one of the most significant threats to human health on a global scale. Hence, the development of effective cancer prevention strategies, as well as the discovery of novel therapeutic agents against cancer, is urgently required. In light of this challenge, this research aimed to evaluate the effects of several potent bioactive peptides and proteins contained in crocodile white blood cell extract (cWBC) against LU-1, LNCaP, PC-3, MCF-7, and CaCo-2 cancer cell lines. The results demonstrate that 25, 50, 100, and 200 µg/ml cWBC exhibits a strong cytotoxic effect against all investigated cell lines (IC50 70.34-101.0 µg/ml), while showing no signs of cytotoxicity towards noncancerous Vero and HaCaT cells. Specifically, cWBC treatment caused a significant reduction in the cancerous cells' colony forming ability. A remarkable suppression of cancerous cell migration was observed after treatment with cWBC, indicating potent antimetastatic properties. The mechanism involved in the cancer cell cytotoxicity of cWBC may be related to apoptosis induction, as evidenced by typical apoptotic morphology features. Moreover, certain cWBC concentrations induced significant overproduction of ROS and significantly inhibited the S-G2/M transition in the cancer cell. The molecular mechanisms of cWBC in apoptosis induction were to decrease Bcl-2 and XIAP expression levels and increase the expression levels of caspase-3, caspase-8, and p53. These led to a decrease in the expression level of the cell cycle-associated gene cyclin-B1 and the arrest of cell population growth. Consequently, these findings demonstrate the prospect of the use of cWBC for cancer therapy.

Induced pluripotent stem cells derived from an autosomal dominant lateral temporal epilepsy (ADLTE) patient carrying S473L mutation in leucine-rich glioma inactivated 1 (LGI1).

Autosomal dominant lateral temporal epilepsy (ADLTE) is an inherited epileptic syndrome, and it is associated with mutations of leucine-rich glioma inactivated 1 (LGI1) gene. The underlying mechanisms of ADLTE are still unknown, as human neurons are difficult to obtain as a research tool. Human induced pluripotent stem cells (iPSCs) allow the generation of patient-derived neuronal cells in a dish, and can be a promising tool to model ADLTE. Here, we report the establishment of human iPSCs from an ADLTE patient carrying LGI1 mutation (c.1418C>T, p.Ser473Leu).

Bioactive Constituents from an Endophytic Fungus, Penicillium polonicum NFW9, Associated with Taxus fauna.

BACKGROUND: Endophytic fungi are being recognized as vital and untapped sources of a variety of structurally novel and unique bioactive secondary metabolites in the field of natural products drug discovery. Herein, this study reports the isolation and characterization of secondary metabolites from an endophytic fungus Penicillium polonicum (NFW9) associated with Taxus fuana. METHOD: The extracts of the endophytic fungus cultured on potato dextrose agar were purified using several chromatographic techniques. Biological evaluation was performed based on their abilities to inhibit tumor necrosis factor-alpha (TNF-α)-induced nuclear factor-kappa B (NF-κB) and cytotoxicity assays. RESULTS: Bioactivity-directed fractionation of the ethyl acetate extract of a fermentation culture of an endophytic fungus, Penicillium polonicum led to the isolation of a dimeric anthraquinone, (R)- 1,1',3,3',5,5'-hexahydroxy-7,7'-dimethyl[2,2'-bianthracene]-9,9',10,10'-tetraone (1), a steroidal furanoid (-)-wortmannolone (2), along with three other compounds (3-4). Moreover, this is the first report on the isolation of compound 1 from an endophytic fungus. All purified metabolites were characterized by NMR and MS data analyses. The stereo structure of compound 1 was determined by the measurement of specific optical rotation and CD spectrum. The relative stereochemistry of 2 was confirmed by single-crystal X-ray diffraction. Compounds 2-3 showed inhibitory activities in the TNF-α-induced NF-κB assay with IC50 values in the range of 0.47-2.11 µM. Compounds 1, 4 and 5 showed moderate inhibition against NF-κB and cancer cell lines. CONCLUSION: The endophytic fungus Penicillium polonicum of Taxus fuana is capable of producing biologically active natural compounds. Our results provide a scientific rationale for further chemical investigations into endophyte-producing natural products, drug discovery and development.

Miliusanes, a class of cytotoxic agents from Miliusa sinensis.

Bioassay-directed fractionation of the leaves, twigs, and flowers of Miliusa sinensis Finet and Gagnep. (Annonaceae) led to the isolation of a new class of potential anticancer lead molecules. They are a cluster of compounds composed of a C(18) carbon skeleton, a known but heretofore unnamed type, which we have designated as miliusane. Two known (1 and 2) as well as 20 new miliusanes (3-22) have been isolated and identified. They belong to two substructural classes of miliusanes. One subclass (1-19) was determined to be composed of a gamma-lactone spiro-ring system, the opening of which led to the second group of compounds (21 and 22) containing a tetrahydrofuran ring system. Compounds 1-3, 5, 8, 9, 18, 20, and 21 demonstrated significant cytotoxic activity in our cancer cell line panel comprising KB, Col-2, LNCaP, Lu-1, MCF-7, and HUVEC. The structures were determined by spectroscopic and chemical methods. The structure of miliusate was further confirmed by X-ray crystallographic analysis. The absolute stereochemistry of miliusanes was established by the Mosher ester method. Forty-two modified miliusane derivatives were also prepared and evaluated for their cytotoxic activities.

Rourinoside and rouremin, antimalarial constituents from Rourea minor.

Bioassay-directed fractionation of the antimalarial active CHCl(3) extract of the dried stems of Rourea minor (Gaertn.) Aubl. (Connaraceae) liana led to isolation of two glycosides, rourinoside (1) and rouremin (2), as well as five known compounds, 1-(26-hydroxyhexacosanoyl)-glycerol (3), 1-O-beta-D-glucopyranosyl-(2S,3R,4E-8Z)-2-N-(2'-hydroxypalmitoyl)-octadecasphinga-4,8-dienine, 9S,12S,13S-trihydroxy-10E-octadecenoic acid, dihydrovomifoliol-9-beta-D-glucopyranoside, and beta-sitosterol glucoside. Compounds 1-3 showed weak in vitro activities against Plasmodium falciparum. Their structures and stereochemistry were elucidated by spectroscopic methods and selected enzyme hydrolysis.

Litsea Species as Potential Antiviral Plant Sources.

Litsea verticillata Hance (Lauraceae), a Chinese medicine used to treat swelling caused by injury or by snake bites, was the first plant identified by our National Institutes of Health (NIH)-funded International Cooperative Biodiversity Group (ICBG) project to exhibit anti-HIV activities. From this plant, we discovered a class of 8 novel litseane compounds, prototypic sesquiterpenes, all of which demonstrated anti-HIV activities. In subsequent studies, 26 additional compounds of different structural types were identified. During our continuing investigation of this plant species, we identified two new litseanes, litseaverticillols L and M, and a new sesquiterpene butenolide, litseasesquibutenolide. Litseaverticillols L and M were found to inhibit HIV-1 replication, with an IC[Formula: see text] value of 49.6[Formula: see text][Formula: see text]M. To further determine the antiviral properties of this plant, several relatively abundant isolates, including a litseane compound, two eudesmane sesquiterpenes and three lignans, were evaluated against an additional 21 viral targets. Lignans 8 and 9 were shown to be active against the Epstein-Barr Virus (EBV), with EC[Formula: see text] values of 22.0[Formula: see text][Formula: see text]M ([Formula: see text]) and 16.2[Formula: see text][Formula: see text]M ([Formula: see text]), respectively. Since many antiviral compounds have been discovered in L. verticillata, we further prepared 38 plant extracts made from the different plant parts of 9 additional Litsea species. These extracts were evaluated for their anti-HIV and cytotoxic activities, and four of the extracts, which ranged across three different species, displayed 97-100% inhibitory effects against HIV replication without showing cytotoxicity to a panel of human cell lines at a concentration of 20 µg/mL.