Antiretroviral agents as inhibitors of both human immunodeficiency virus type 1 integrase and protease

Recent Advances in the Discovery and Development of Anti-HIV Natural Products

Acquired immunodeficiency syndrome (AIDS) caused by human immunodeficiency virus (HIV) infection is a serious public problem threatening global health. At present, although "cocktail therapy" has achieved significant clinical effects, HIV still cannot be completely eradicated. Furthermore, long-term antiviral treatment has caused problems such as toxic side effects, the emergence of drug-resistant viruses, and poor patient compliance. Therefore, it is highly necessary to continue to search for high-efficient, low-toxic anti-HIV drugs with new mechanisms. Natural products have the merits of diverse scaffolds, biological activities, and low toxicity that are deemed the important sources of drug discovery. Thus, finding lead compounds from natural products followed by structure optimization has become one of the important ways of modern drug discovery. Nowadays, many natural products have been found, such as berberine, gnidimacrin, betulone, and kuwanon-L, which exert effective anti-HIV activity through immune regulation, inhibition of related functional enzymes in HIV replication, and anti-oxidation. This paper reviewed these natural products, their related chemical structure optimization, and their anti-HIV mechanisms.

DMAP-catalyzed Efficient and Convenient Approach for the Synthesis of 3,3′-(Arylmethylene)bis(2-Hydroxynaphthalene-1,4-Dione) Derivatives

For the first time the 4-dimethylaminopyridine (DMAP) catalyzed straightforward and efficient procedure has been developed for the synthesis of 3,3′-(arylmethylene) bis(2-hydroxynaphthalene-1,4-dione) derivatives starting from lawsone (2-hydroxy-1,4-naphthoquinone) and a variety of (hetero)aromatic aldehydes in ethanol under microwave irradiation. Three of nine synthesized compounds are new. This method provides notable advantages over existing procedures including use of non-traditional basic catalyst and environmentally benign solvent, mild reaction conditions, excellent yields, short reaction time and simple workup.

Design, synthesis, docking and biological evaluation of chalcones as promising antidiabetic agents

Diabetes mellitus (DM) is a serious chronic metabolic disorder which occurs due to dysfunction of insulin and therapeutic approaches are poor. It is an under estimation that 387 million people currently suffering globally with diabetic and more than 592 million people may be affected by 2030. It makes an urgent necessity to discover novel drugs to control amplified diabetic populations. In this study, amino chalcones (3a-j) were synthesized and hydroxy chalcones (3g-j) were isolated from natural source such as Sophora interrupta, Clerodendrum phlomidis and Andrographis macrobotrys. Structural elucidation was carried out using Mass, ¹H and ¹³C NMR Spectra. In vivo studies were carried out with alloxan induced diabetic rats (100 mg/kg) which reveals compounds 3c, 3a and 3h have significant antidiabetic efficacy with decreased blood glucose levels in the diabetic rats while compared with control rats. Besides, docking studies with aldose reductase, dipeptidyl peptidase, PPAR and glucosidase were monitored which accomplishes that the compounds 3c, 3i, 3a and 3d have eloquent binding affinity (kcal/mol) with aldose reductase, besides the chalcones 3c, 3b, 3d, 3e and 3i were also showed inhibition with DPP-IV, PPAR-α and α-glucosidase. Also, these compounds explicated distinct interactions i.e., π-π, π-cationic, polar, electrostatic and hydrophobic bonds were observed with key residues of binding pockets. Bioavailability is disclosed with Lipinski rule of five and the design pharmacokinetic as well as pharmacodynamic properties are reliable. Therefore, chalcones were implied as antidiabetic leads for in further studies and could be worthwhile for the development of new classes of effective antidiabetic agents.

Dicoumarol derivatives: Green synthesis and molecular modelling studies of their anti-LOX activity

Dicoumarol derivatives were synthesized in the InCl3 catalyzed pseudo three-component reactions of 4-hydroxycoumarin with aromatic aldehydes in excellent yields. The reactions were performed in water under microwave irradiation. All synthesized compounds were characterized using NMR, IR, and UV-Vis spectroscopy, as well as with TD-DFT. Obtained dicoumarols were subjected to evaluation of their in vitro lipid peroxidation and soybean lipoxygenase inhibition activities. It was shown that five of ten examined compounds (3e, 3h, 3b, 3d, 3f) possess significant potential of antilipid peroxidation (84-97%), and that compounds 3b, 3e, 3h provided the highest soybean lipoxygenase (LOX-Ib) inhibition (IC50 = 52.5 µM) and 3i somewhat lower activity (IC50 = 55.5 µM). The bioactive conformations of the best LOX-Ib inhibitors were obtained by means of molecular docking and molecular dynamics. It was shown that, within the bioactive conformations interior to LOX-Ib active site, the most active compounds form the pyramidal structure made of two 4-hydroxycoumarin cores and a central phenyl substituent. This form serves as a spatial barrier which prevents LOX-Ib Fe2+/Fe3+ ion activity to generate the coordinative bond with the C13 hydroxyl group of the α-linoleate. It is worth pointing out that the most active compounds 3b, 3e, 3h and 3i can be candidates for further examination of their in vitro and in vivo anti-inflammatory activity and that molecular modeling study results provide possibility to screen bioactive conformations and elucidate the mechanism of dicoumarols anti-LOX activity.

Synthesis and Antiviral Activity of Novel 1,4-Pentadien-3-one Derivatives Containing a 1,3,4-Thiadiazole Moiety

1,4-Pentadien-3-one derivatives derived from curcumin possess excellent inhibitory activity against plant viruses. On the basis of this finding, a series of novel 1,4-pentadien-3-one derivatives containing a 1,3,4-thiadiazole moiety were designed and synthesized, and their structures confirmed by IR, ¹H-NMR, and ¹³C-NMR spectroscopy and elemental analysis. The antiviral activities of the title compounds were evaluated against tobacco mosaic virus (TMV) and cucumber mosaic virus (CMV) in vivo. The assay results showed that most of compounds had remarkable antiviral activities against TMV and CMV, among which compounds 4b, 4h, 4i, 4k, 4o, and 4q exhibited good curative, protection, and inactivation activity against TMV. Compounds 4h, 4i, 4k, 4l, 4o, and 4q exhibited excellent protection activity against TMV, with EC₅₀ values of 105.01, 254.77, 135.38, 297.40, 248.18, and 129.87 μg/mL, respectively, which were superior to that of ribavirin (457.25 µg/mL). In addition, preliminary SARs indicated that small electron-withdrawing groups on the aromatic ring were favorable for anti-TMV activity. This finding suggests that 1,4-pentadien-3-one derivatives containing a 1,3,4-thiadiazole moiety may be considered as potential lead structures for discovering new antiviral agents.

Therapeutic potential of coumarins as antiviral agents

Coumarins have received a considerable attention in the last three decades as a lead structures for the discovery of orally bioavailable non-peptidic antiviral agents. A lot of structurally diverse coumarins analogues were found to display remarkable array of affinity with the different molecular targets for antiviral agents and slight modifications around the central motif result in pronounced changes in its antiviral spectrum. This manuscript thoroughly reviews the design, discovery and structure-activity relationship studies of the coumarin analogues as antiviral agents focusing mainly on lead optimization and its development into clinical candidates.

Homogeneous High-Throughput Screening Assays for HIV-1 Integrase 3β-Processing and Strand Transfer Activities

HIV-1 integrase (HIV-IN) is a well-validated antiviral drug target catalyzing a multistep reaction to incorporate the HIV-1 provirus into the genome of the host cell. Smallmolecule inhibitors of HIV-1 integrase that specifically target the strand transfer step have demonstrated efficacy in the suppression of virus propagation. However, only fewspecific strand transfer inhibitors have been identified to date, and the need to screen for novel compound scaffolds persists. Here, the authors describe 2 homogeneous time-resolved fluorescent resonance energy transfer-based assays for the measurement of HIV-1 integrase 3'-processing and strand transfer activities. Both assayswere optimized for high-throughput screening formats, and a diverse library containingmore than 1million compoundswas screened in 1536-well plates for HIV-IN strand transfer inhibitors. As a result, compounds were found that selectively affect the enzymatic strand transfer reaction over 3β processing. Moreover, several bioactivemoleculeswere identified that inhibited HIV-1 reporter virus infection in cellularmodel systems. In conclusion, the assays presented herein have proven their utility for the identification ofmechanistically interesting and biologically active inhibitors of HIV-1 integrase that hold potential for further development into potent antiviral drugs.

Isotopic splitting patterns in the (13) C NMR spectra of some partially deuterated 1-aryl-2-(phenyldiazenyl)butane-1,3-dione and 4-hydroxy-3-(phenyldiazenyl)-2H-chromen-2-one: evidence for elucidation of tautomeric forms

Nuclear magnetic resonance spectra of synthesized azo dyes derived from aniline derivatives in reaction with benzoylacetone and 4-hydroxycoumarin were studied in both CDCl3 and (CD3 )2 SO (two drops of D2 O were added into solutions of dyes). All dyes showed intramolecular hydrogen bonding. Dyes derived from o-nitro aniline in the reaction with benzoylacetone, and 4-hydroxycoumarin showed bifurcated intramolecular hydrogen bonds. The solvent-substrate proton exchange of dyes derived from benzoylacetone and 4-hydroxycoumarin was examined in the presence of two drops of D2 O. Among ten dye samples, two dyes derived from benzoylacetone did not show deuteration, three dyes showed partial deuteration and five dyes showed full deuteration under similar conditions. For the partially deuterated dyes the β-isotope effect in (13) C splitting was investigated and was used for the determination of the predominant tautomeric form.

Design, synthesis, antiviral activity and three-dimensional quantitative structure-activity relationship study of novel 1,4-pentadien-3-one derivatives containing the 1,3,4-oxadiazole moiety

BACKGROUND

1,4-Pentadien-3-one and 1,3,4-oxadiazole derivatives possess good antiviral activities, and their substructure units are usually used in antiviral agent design. In order to discover novel molecules with high antiviral activities, a series of 1,4-pentadien-3-one derivatives containing the 1,3,4-oxadiazole moiety were designed and synthesised.

RESULTS

Bioassays showed that most of the title compounds exhibited good inhibitory activities against tobacco mosaic virus (TMV) in vivo. The compound 8f possessing the best protective activity against TMV had an EC50 value of 135.56 mg L(-1) , which was superior to that of ribavirin (435.99 mg L(-1) ). Comparative molecular field analysis (CoMFA) and comparative molecular similarity index analysis (CoMSIA) techniques were used in three-dimensional quantitative structure-activity relationship (3D-QSAR) studies of protective activities, with values of q(2) and r(2) for the CoMFA and CoMSIA models of 0.751 and 0.775 and 0.936 and 0.925 respectively. Compound 8k with higher protective activity (EC50 = 123.53 mg L(-1) ) according to bioassay was designed and synthesised on the basis of the 3D-QSAR models.

CONCLUSION

Some of the title compounds displayed good antiviral activities. 3D-QSAR models revealed that the appropriate compact electron-withdrawing and hydrophobic group at the benzene ring could enhance antiviral activity. These results could provide important structural insights for the design of highly active 1,4-pentadien-3-one derivatives.

Curcumin and its analogues: a potential natural compound against HIV infection and AIDS

No safe and effective cure currently exists for human immunodeficiency virus (HIV). However, antiretroviral therapy can prolong the lives of HIV patients and lowers the secondary infections. Natural compounds, which are considered to be pleiotropic molecules, could be useful against HIV. Curcumin, a yellow pigment present in the spice turmeric (Curcuma longa), can be used for the treatment of several diseases including HIV-AIDS because of its antioxidant, anti-inflammatory, anticancer, antiviral, and antibacterial nature. In this review we have summarized that how curcumin and its analogues inhibit the infection and replication of viral genes and prevent multiplicity of HIV. They are inhibitors of HIV protease and integrase. Curcumin also inhibits Tat transactivation of the HIV1-LTR genome, inflammatory molecules (interleukins, TNF-α, NF-κB, COX-2) and HIV associated various kinases including tyrosine kinase, PAK1, MAPK, PKC, cdk and others. In addition, curcumin enhances the effect of conventional therapeutic drugs and minimizes their side effects.

Targeting HIV-1 integrase with strand transfer inhibitors

HIV-1 integrase (IN) is a retroviral enzyme essential for integration of genetic material into the DNA of the host cell and hence for viral replication. The absence of an equivalent enzyme in humans makes IN an interesting target for anti-HIV drug design. This review briefly overviews the structural and functional properties of HIV-1 IN. We analyze the binding modes of the established drugs, clinical candidates and a comprehensive library of leads based on innovative chemical scaffolds of HIV-1 IN strand transfer inhibitors (INSTIs). Computational clustering techniques are applied for identifying structural features relating to bioactivity. From bio- and chemo-informatics analyses, we provide novel insights into structure-activity relationships of INSTIs and elaborate new strategies for design of innovative inhibitors.

Synthesis, leishmanicidal activity and theoretical evaluations of a series of substituted bis-2-hydroxy-1,4-naphthoquinones

A series of eight substituted bis-2-hydroxy-1,4-naphthoquinone derivatives was synthesized through lawsone condensation with various aromatic and aliphatic aldehydes under mild acidic conditions. The title compounds were evaluated for antileishmanial activity in vitro against Leishmania amazonensis and Leishmania braziliensis promastigotes; six compounds showed good activity without significant toxic effects. The compound with the highest activity was used for an in vivo assay with Leishmania amazonensis.

Computational models on quantitative prediction of bioactivity of HIV-1 integrase 3' processing inhibitors

In this study, four computational quantitative structure-activity relationship (QSAR) models were built to predict the bioactivity of 3' processing (3'P) inhibitors of HIV-1 integrase. Some 453 inhibitors whose bioactivity values were detected by the radiolabelling method were collected. The molecular structures were represented with MOE descriptors. In total, 21 descriptors were selected for modelling. All inhibitors were divided into a training set and a test set with two methods: (1) by a Kohonen's self-organizing map (SOM); (2) by a random selection. For every training set and test set, a multilinear regression (MLR) analysis and a support vector machine (SVM) were used to establish models, respectively. For the training/test set divided by SOM, the correlation coefficients (r) were over 0.84, and for the training/test set split randomly, the r values were over 0.86. Some molecular properties such as hydrogen bond donor capacity, atomic partial charge properties, molecular refractivity, the number of aromatic bonds and molecular surface area, volume and shape properties played important roles for inhibiting 3' processing step of HIV-1 integrase.

A blunted anxiolytic like effect of curcumin against acute lead induced anxiety in rat: involvement of serotonin

Anxiety is one of the most common mental disorders sharing extreme or pathological anxiety states as the primary disturbance in mood or emotional tone, with increased fear and exaggerated acute stress responses. Medicinal plants are very variable, but some of them are used as a spice such as curcumin (Curcuma longa). Curcumin shows a wide range of pharmacological potentialities, however, little is known about its anxiolytic properties. The aim of our study was to assess the anti-anxiety potential of curcumin extract against experimental lead induced-anxiety in rats. Experiments were carried out on male Wistar rats intoxicated acutely with an intraperitoneal injection of Pb (25mg/kg B.W.) and/or concomitantly with administration of curcumin (30 mg/kg B.W.) for 3 days. Using immunohistochemistry and anxiety assessment tests (dark light box and elevated plus maze), we evaluated, respectively, the expression of serotonin (5HT) in the dorsal raphe nucleus (DRN) and the anxiety state in our animals. Our results showed, for the first time, a noticeable anxiolytic effect of curcumin against lead induced anxiety in rats and this may possibly result from modulation of central neuronal monoaminergic neurotransmission, especially serotonin, which has shown a significant reduction of the immunoreactivity within the DRN.

Multimodal mechanism of action of allosteric HIV-1 integrase inhibitors

Integrase (IN) is required for lentivirus replication and is a proven drug target for the prevention of AIDS in HIV-1-infected patients. While clinical strand transfer inhibitors disarm the IN active site, allosteric inhibition of enzyme activity through the disruption of IN-IN protein interfaces holds great therapeutic potential. A promising class of allosteric IN inhibitors (ALLINIs), 2-(quinolin-3-yl) acetic acid derivatives, engage the IN catalytic core domain dimerisation interface at the binding site for the host integration co-factor LEDGF/p75. ALLINIs promote IN multimerisation and, independent of LEDGF/p75 protein, block the formation of the active IN-DNA complex, as well as inhibit the IN-LEDGF/p75 interaction in vitro. Yet, rather unexpectedly, the full inhibitory effect of these compounds is exerted during the late phase of HIV-1 replication. ALLINIs impair particle core maturation as well as reverse transcription and integration during the subsequent round of virus infection. Recapitulating the pleiotropic phenotypes observed with numerous IN mutant viruses, ALLINIs provide insight into underlying aspects of IN biology that extend beyond its catalytic activity. Therefore, in addition to the potential to expand our repertoire of HIV-1 antiretrovirals, ALLINIs afford important structural probes to dissect the multifaceted nature of the IN protein throughout the course of HIV-1 replication.

Computational design of a full-length model of HIV-1 integrase: modeling of new inhibitors and comparison of their calculated binding energies with those previously studied

A full-length model of integrase (IN) of the human immunodeficiency virus type 1 (HIV-1) was constructed based on the distinctly resolved X-ray crystal structures of its three domains, named N-terminal, catalytic core and C-terminal. Thirty-one already known inhibitors with varieties of structural differences as well as nine newly tested ones were docked into the catalytic core. The molecular dynamic (MD) and binding properties of these complexes were obtained by MD calculations. The binding energies calculated by molecular mechanic/Poisson Boltzmann solvation area were significantly correlationed with available IC50. Four inhibitors including two newly designed were also docked into the full-length model and their MD behaviors and binding properties were calculated. It was found that one of the newly designed compounds forms a better complex with HIV-1 IN compared to the rest including raltegravir. MD calculations were performed with AMBER suite of programs using ff99SB force field for the proteins and the general Amber force field for the ligands. In conclusion, the results have produced a promising standpoint not only in the construction of the full-length model but also in development of new drugs against it. However, the role of multimer formation and the involvement of DNAs, and their subsequent effect on the complexation and inhibition, are required to arrive at a conclusive decision.

Raltegravir flexibility and its impact on recognition by the HIV-1 IN targets

HIV-1 IN is a pertinent target for the development of AIDS chemotherapy. The first IN-specific inhibitor approved for the treatment of HIV/AIDS, RAL, was designed to block the ST reaction. We characterized the structural and conformational features of RAL and its recognition by putative HIV-1 targets - the unbound IN, the vDNA, and the IN•vDNA complex - mimicking the IN states over the integration process. RAL binding to the targets was studied by performing an extensive sampling of the inhibitor conformational landscape and by using four different docking algorithms: Glide, Autodock, VINA, and SurFlex. The obtained data evidenced that: (i) a large binding pocket delineated by the active site and an extended loop in the unbound IN accommodates RAL in distinct conformational states all lacking specific interactions with the target; (ii) a well-defined cavity formed by the active site, the vDNA, and the shortened loop in the IN•vDNA complex provide a more optimized inhibitor binding site in which RAL chelates Mg(2+) cations; (iii) a specific recognition between RAL and the unpaired cytosine of the processed DNA is governed by a pair of strong H-bonds similar to those observed in DNA base pair G-C. The identified RAL pose at the cleaved vDNA shed light on a putative step of RAL inhibition mechanism. This modeling study indicates that the inhibition process may include as a first step RAL recognition by the processed vDNA bound to a transient intermediate IN state, and thus provides a potentially promising route to the design of IN inhibitors with improved affinity and selectivity.

Antileishmanial activity evaluation of bis-lawsone analogs and DNA topoisomerase-I inhibition studies

For the development of potent novel antileishmanial agents, 3,3'-(arylmethylene)bis(2-hydroxynaphthalene-1,4 dione) derivatives were synthesized from lawsone and evaluated for cytotoxicity on Leishmania donovani promastigotes as well as on leishmanial DNA topoisomerase-I. Enzyme inhibition studies were conducted with simultaneous and preincubation conditions. Total inhibition is compared to camptothecin (CPT), which was taken as positive control on both the systems of enzyme inhibition. The range of activity varied from 37.5 to 70 µM in simultaneous assay and 13-16 µM in preincubation assay. Furthermore, when evaluated against L. donovani promastigotes, the synthesized compounds exhibited the activity ranging from 2 to 14 µM. The results revealed that all the compounds exhibit promising antileishmanial activity.

Synthesis and antiviral bioactivity of novel (1E, 4E)-1-aryl-5-(2-(quinazolin-4-yloxy)phenyl)-1,4-pentadien-3-one derivatives

A series of novel (1E, 4E)-1-aryl-5-[2-(quinazolin-4-yloxy)phenyl]-1,4-pentadien-3-one derivatives were designed and synthesized by reacting substituent aldehyde with intermediates 4a-f. Antiviral bioassays indicated that most of the compounds exhibited promising ex vivo antiviral bioactivities against tobacco mosaic virus (TMV) and cucumber mosaic virus (CMV) at 500 μg/mL. The relationship between structure and antiviral activity was also discussed. Compounds 5a, 6e, and 6g could possess appreciable protective bioactivities on TMV ex vivo by approximately 50% (EC50) at 257.7, 320.7 and 243.3 μg/mL. This study is the first to demonstrate that (1E, 4E)-1-aryl-5-(2-(quinazolin-4-yloxy)phenyl)-1,4-pentadien-3-one can be used to develop potential virucides for plants.

Prediction of bioactivity of HIV-1 integrase ST inhibitors by multilinear regression analysis and support vector machine

In this study, four computational quantitative structure-activity relationship models were built to predict the biological activity of HIV-1 integrase strand transfer (ST) inhibitors. 551 Inhibitors whose bioactivities were detected by radiolabeling method were collected. The molecules were represented with 20 selected MOE descriptors. All inhibitors were divided into a training set and a test set with two methods: (1) by a Kohonen's self-organizing map (SOM); (2) by a random selection. For every training set and test set, a multilinear regression (MLR) analysis and a support vector machine (SVM) were used to establish models, respectively. For the test set divided by SOM, the correlation coefficients (rs) were over 0.91, and for the test set split randomly, the rs were over 0.86.

Therapeutic role of curcumin in prevention of biochemical and behavioral aberration induced by alcoholic neuropathy in laboratory animals

Painful peripheral neuropathy induced by chronic ethanol consumption is a major medico-socioeconomical problem. The objective of present investigation was to study the effect of curcumin (20, 40 and 80mg/kg; p.o.) in alcohol-induced neuropathy in rats. Ethanol (35% v/v, 10g/kg; p.o.) was administered for 10 weeks which showed a significant decrease in thermal hyperalgesia, mechanical hyperalgesia, mechanical allodynia and nerve conduction velocity. It caused enhanced malondialdehyde, oxidative-nitrosative stress, total calcium levels, inflammatory mediators (TNF-α and IL-1β levels) along with DNA damage. Co-administration of curcumin and α-tocopherol for 10 weeks significantly and dose-dependently improved nerve functions, biochemical as well as molecular parameters and DNA damage in sciatic nerve of ethanol treated rats. Hence, it was concluded that curcumin is of potent therapeutic value in the amelioration of alcoholic neuropathy in rats and acts by inhibition of pro-inflammatory mediators like TNF-α and IL-1β.

Benzylidene-bis-(4-hydroxycoumarin) and benzopyrano-coumarin derivatives: synthesis, ¹H/¹³C-NMR conformational and X-ray crystal structure studies and in vitro antiviral activity evaluations

We report on the synthesis of 4-hydroxycoumarin dimers 1-15 bearing an aryl substituent on the central linker and fused benzopyranocoumarin derivatives 16-20 and on their in vitro broad anti-DNA and RNA virus activity evaluations. The chemical identities and structure of compounds 1-20 were deduced from their homo- and heteronuclear NMR measurements whereas the conformational properties of 5, 14 and 20 were assessed by the use of 1D difference NOE enhancements. Unequivocal proof of the stereostructure of compounds 7, 9, 16 and 18 was obtained by single crystal X-ray diffraction method. The X-ray crystal structure analysis revealed that two 4-hydroxycoumarin moieties in the 4-trifluoromethylphenyl- and 2-nitrophenyl derivatives (compounds 7 and 9, respectively) are intramolecularly hydrogen-bonded between hydroxyl and carbonyl oxygen atoms. Consequently, the compounds 7 and 9 adopt conformations in which two 4-hydroxy-coumarin moieties are anti-disposed. Antiviral activity evaluation results indicated that the 4-bromobenzylidene derivative of bis-(4-hydroxycoumarin) (compound 3) possesses inhibitory activity against HSV-1 (KOS), HSV-2 (G), vaccinia virus and HSV-1 TK⁻ KOS (ACVr) at a concentration of 9-12 μM and at a minimum cytotoxic concentration (MCC) greater than 20 μM. Compounds 4-6, 8, and 20 were active against feline herpes virus (50% effective concentration, EC₅₀ = 5-8.1 μM), that is at a 4-7-fold lower concentration than the MCC.

HIV-1 Integrase Inhibitors: A Review of Their Chemical Development

Highly active antiretroviral therapy (HAART) significantly decreases plasma viral load, increases CD4+ T-cell counts in HIV-1-infected patients and has reduced progression to AIDS in developed countries. However, adverse side effects, and emergence of drug resistance, mean there is still a demand for new anti-HIV agents. The HIV integrase (IN) is a target that has been the focus of rational drug design over the past decade. In 2007, raltegravir was the first IN inhibitor approved by the US Food and Drug Administration for antiretroviral combination therapy, while another IN inhibitor, elvitegravir, is currently in Phase III clinical trials. This article reviews the development and resistance profiling of small molecule HIV-1 IN inhibitors.

Traditional herbal medicine in far-west Nepal: a pharmacological appraisal

BACKGROUND

Plant species have long been used as principal ingredients of traditional medicine in far-west Nepal. The medicinal plants with ethnomedicinal values are currently being screened for their therapeutic potential but their data and information are inadequately compared and analyzed with the Ayurveda and the phytochemical findings.

METHODS

The present study evaluated ethnomedicinal plants and their uses following literature review, comparison, field observations, and analysis. Comparison was made against earlier standard literature of medicinal plants and ethnomedicine of the same area, the common uses of the Ayurveda and the latest common phytochemical findings. The field study for primary data collection was carried out from 2006-2008.

RESULTS

The herbal medicine in far-west Nepal is the basis of treatment of most illness through traditional knowledge. The medicine is made available via ancient, natural health care practices such as tribal lore, home herbal remedy, and the Baidhya, Ayurveda and Amchi systems. The traditional herbal medicine has not only survived but also thrived in the trans-cultural environment with its intermixture of ethnic traditions and beliefs. The present assessment showed that traditional herbal medicine has flourished in rural areas where modern medicine is parsimoniously accessed because of the high cost and long travel time to health center. Of the 48 Nepalese medicinal plants assessed in the present communication, about half of the species showed affinity with the common uses of the Ayurveda, earlier studies and the latest phytochemical findings. The folk uses of Acacia catechu for cold and cough, Aconitum spicatum as an analgesic, Aesculus indica for joint pain, Andrographis paniculata for fever, Anisomeles indica for urinary affections, Azadirachta indica for fever, Euphorbia hirta for asthma, Taxus wallichiana for tumor control, and Tinospora sinensis for diabetes are consistent with the latest pharmacological findings, common Ayurvedic and earlier uses.

CONCLUSIONS

Although traditional herbal medicine is only a primary means of health care in far-west Nepal, the medicine has been pursued indigenously with complementing pharmacology and the Ayurveda. Therefore, further pharmacological evaluation of traditional herbal medicine deserves more attention.