Anti-HIV-1 integrase compound from Pometia pinnata leaves

Abstract

Context: HIV-1 integrase (HIV-1 IN) is a key enzyme involved in the replication cycle of the retrovirus. Any new knowledge on inhibitors of this enzyme could provide essential clues for the development of anti-HIV drugs.

Objective: To evaluate anti-HIV-1 IN activity of some Thai medicinal plant extracts, and the extract that possessed the strongest anti-HIV-1 IN activity was subjected to isolation of the active compounds.

Materials and methods: Ethanol extracts of eight Thai medicinal plants were evaluated for their inhibitory effect against HIV-1 IN. An extract of Pometia pinnata J. R. Forst. & G. Forst (Sapindaceae) leaves that possessed the strongest anti-HIV-1 IN activity was fractionated to isolate the active compounds by anti-HIV-1 IN assay-guided isolation process.

Results and discussion: The leaf extract from P. pinnata had the strongest anti-HIV-1 IN activity with an IC₅₀ value of 8.8?µg/mL. An anti-HIV-1 IN assay-guided isolation of the active compounds from a leaf extract of P. pinnata resulted in the isolation of one active compound, identified as proanthocyanidin A2. Proanthocyanidin A2 showed satisfactory anti-HIV-1 IN activity with an IC₅₀ value of 30.1?µM. Three flavonoids, epicatechin, kaempferol-3-O-rhamnoside, quercetin-3-O-rhamnoside; a glycolipid, 1-O-palmitoyl-3-O-[α-.-galactopyranosyl-(1?→?6)-β-.-galactopyranosyl]-sn-glycerol; a steroidal glycoside; stigmasterol-3-O-glucoside; and a pentacyclic triterpenoid saponin, 3-O-α-.-arabinofuranosyl-(1?→?3)-[α-.-rhamnopyranosyl-(1?→?2)]-α-.-arabinopyranosyl hederagenin were also isolated but were inactive at a concentration of 100?µM.     

Enfuvirtide: from basic investigations to current clinical use

Importance of the field: Drug resistance is a major challenge in the treatment of HIV infection. Enfuvirtide is the first entry inhibitor to have been approved for clinical use.

Areas covered in this review: Relevant information through searches of MEDLINE (1998 to June 2010) and meeting abstracts of major HIV/AIDS conferences (2003 – June 2010) using the search terms ‘enfuvirtide’, ‘T-20’ and ‘fusion inhibitor’.

What the reader will gain: Enfuvirtide blocks HIV fusion to host cells. It works against the different HIV-1 variants but is not active against HIV-2. The recommended dosage of enfuvirtide is 90 mg b.i.d. subcutaneously. The two large Phase III pivotal clinical trials TORO 1 and 2 showed that enfuvirtide is an effective therapeutic option as rescue therapy in combination with other active antiretroviral drugs. Resistance to enfuvirtide is conferred by mutations in the HR1 region of gp41. Single and double mutations have been shown to result in high-level resistance to enfuvirtide. Postmarketing studies have been helpful to define more precisely the place of enfuvirtide in the sequence of antiretroviral therapy.

Take home message: The emergence of new compounds and new classes of drugs, highly active against multiresistant virus but more convenient to administer than enfuvirtide, will probably prevent the extensive use of enfuvirtide. This drug remains attractive in some subgroups of patients because of its excellent systemic tolerance and the lack of interactions with the major cytochrome P450 isoenzymes.     

Anti-HIV-1 integrase effect of compounds from Aglaia andamanica leaves and molecular docking study with acute toxicity test in mice

Context: Acquired immunodeficiency syndrome (AIDS) is a serious health problem worldwide. It has been reported that Aglaia andamanica Hiern (Meliaceae) leaves possessed an antiviral effect. Therefore, a search of anti-HIV-1 integrase (HIV-1 IN) agents from A. andamanica is a promising target.

Objective: The objective of this study is to evaluate anti-HIV-1 IN activity of isolated compounds from A. andamanica using an in vitro assay and molecular docking study as well as testing acute toxicity in mice using the up and down method.

Materials and methods: The leaves and compounds (3–100?μg/mL) from A. andamanica were determined for the anti-HIV-1 IN effect using the multiplate integration assay (MIA) by detection the absorbance of the final product, p-nitrophenol, at 405?nm. The molecular docking with the HIV-1 IN of the active compound N-methyl-trans-4-hydroxy-l-proline (10) was also studied. The Swiss albino mice were used for an acute toxicity test.

Results and discussion: Among the isolated compounds, 10 showed marked anti-HIV-1 IN effect with an IC₅₀ value of 11.8?μg/mL, whereas other compounds were inactive (IC₅₀ value?>?100?μg/mL). The molecular docking of compound 10 with an HIV-1 IN enzyme was also studied. The result revealed that this compound formed the hydrogen bonding with the Thr66, Asn155, and Lys159 of the HIV-1 IN binding site. The acute toxicity of the A. andamanica extract was not observed at the dose 2000?mg/kg mice. This is the first report of A. andamanica for anti-HIV-1 IN activity.     

Evaluation of Antibacterial Activities of Medicinal Plants Widely Used Among AIDS Patients in Thailand

Abstract

Antibacterial activity of 12 selected Thai medicinal plants used as self-medication by HIV/AIDS patients in Thailand was studied. Thirty-nine chloroform, methanol, and aqueous extracts from these plants were investigated for their antibacterial activity against important pathogenic bacteria commonly associated with AIDS infection. These included Staphylococcus aureus., methicillin-resistant Staphylococcus aureus. (MRSA), Streptococcus mutans., and Salmonella typhi.. Inhibition of growth was tested using paper disk agar diffusion method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by agar microdilution method and agar dilution method in Petri dishes with millipore filters. The Gram-positive bacteria were proved to be susceptible to the chloroform extracts of Alpinia galanga. (L.) Willd., Boesenbergia rotunda. Mansf. (L.), Piper betle. (L.), Spilanthes acmella. (L.) Murray, and Zingiber zerumbet. (L.) Roscoe ex Sm. and the methanol extract of Boesenbergia rotunda.. Chloroform extract of Alpinia galanga. demonstrated the greatest inhibition zones of 29.1 and 23.7 mm against Staphylococcus aureus. and MRSA, respectively. The MIC values of this extract against Staphylococcus aureus. and MRSA were 128 and 256 µg/ml and the MBC values were 256 and 256 µg/ml, respectively. An active compound, 1′-acetoxy-chavicol acetate, was identified with MIC values against MRSA and Staphylococcus aureus. of 64 and 128 µg/ml, respectively.     

Anti-Helicobactor pylori activity of some Jordanian medicinal plants

Context: Natural flora are considered a major source of new agents for the treatment of Helicobactor pylori. The plants used in this study were selected based on previous traditional use.

Objective: In this study, we evaluated the effect of extracts of 16 medicinal plants grown in Jordan against clinical isolates of H. pylori.

Materials and methods: Tested plant extracts included Aloysia triphylla (L'Her.) Britton (Verbenaceae), Anethum graveolens L. (Apiaceae), Artemisia inculata Delile (Asteraceae), Capparis spinosa L. (Capparaceae), Crataegus aronia (L.) Bosc ex. DC. (Rosaceae), Inula viscose (L.) Ait (Asteraceae), Lavandula officinalis Chaix. (Lamiaceae), Lepidium sativum L. (Cruciferae), Origanum syriaca L. (Lamiaceae), Paronychia argentea Lam. (Caryophyllaceae), Passiflora incarnate L. (Passifloraceae), Psidium guajava L. (Myrtaceae), Sarcopoterium spinosum (L.) Spach (Rosaceae), Sesamum indicum L. (Pedaliaceae), Urtica urens L. (Urticaceae) and Varthemia iphionoids Boiss (Asteraceae). Clinical isolates of H. pylori were tested in vitro for susceptibility to each of the above plant crude extracts using disk diffusion method, and the MIC value was determined for each plant extract using the serial dilution method.

Results: Results showed that ethanol extracts of most medicinal plants exerted cytotoxiciy against H. pylori isolates. Among the tested plant extracts, A. triphylla (MIC: 90?µg/mL, MBC: 125?µg/mL) and I. viscosa (MIC: 83?µg/mL, MBC: 104?µg/mL) showed the strongest activity against both isolates of H. pylori.

Discussion and conclusion: Jordanian medicinal plants might be valuable sources of starting materials for the synthesis of new antibacterial agents against H. pylori.     

Effects of methanol extracts from roots,leaves, and fruits of the Lebanese strawberry tree (Arbutus andrachne) on cardiac function together with their antioxidant activity

Context: Several plant-derived natural products have been used in clinical phase for applications in neurological, cardiovascular, and inflammatory diseases. Arbutus andrachne L. (Ericacea) is an evergreen shrub native to the Mediterranean region. Traditionally, the fruits and leaves of Arbutus tree are well known and used as antiseptics, diuretics, blood tonic, and laxatives.

Objective: Data regarding the biological effects of compounds derived from the Lebanese Arbutus andrachne are not available. In the present work, we studied the antioxidant activity of methanol extracts of leaves, fruits, and roots of the plant against electrolysis; together with their effects on the cardiodynamics of isolated perfused rabbit hearts.

Materials and methods: In vitro electrolysis of the different root, leaves, and fruits methanol extracts was evaluated by the amount of free radicals that has been reduced by increasing the concentration of root extracts ranging from 0.5 to 2?mg after 1, 2, 3, and 4?min. Left ventricular pressure (LVP), heart rate (HR), and coronary flow (CR) were investigated in isolated rabbit heart after administration of 0.5, 1, 2, and 2?mg of each methanol extracts plotted against time (0, 0.5, 1.5, 5, and 10?min), according to the Langendorff method. Lipid peroxidation study was performed by the colorimetric method on myocard tissue after incubation with 500?μl of the different methanol extracts. The amount of MDA was determined at 500?nm absorbance after 5?min incubation.

Results: Among the different methanol extracts, the roots showed the highest in vitro antioxidant activity, particularly observed at concentration of 2?mg which completely inhibits free radical generation after 4?min. LVP decreases by 32% at the dose of 2?mg of root extracts after 5?min. No significant effect was observed by the three tested extracts on the heart rate. The three methanol extracts did not show any significant effect on the coronary flow. Moreover, the roots show an increase in the coronary flow at a concentration of 1 and 2?mg/ml during 1?min. Electrolysis on heart tissue treated with the roots extracts shows a decrease in the MDA level from 70.51?±?6.71 to 48.58?±?4.15 nmole/g of tissue.

Discussion and conclusion: Methanol extracts of the roots possess antihypertensive effect that may result from its ability to decrease the LVP together with its protective role by inhibiting free radical generation and significantly decreasing the MDA level of heart tissue.     

Anti-infective effects of Brazilian Caatinga plants against pathogenic bacterial biofilm formation

Abstract

Context: The local communities living in the Brazilian Caatinga biome have a significant body of traditional knowledge on a considerable number of medicinal plants used to heal several maladies.

Objective: Based on ethnopharmacological data, this study screened 23 aqueous plant extracts against two well-known models of biofilm-forming bacteria: Staphylococcus epidermidis and Pseudomonas aeruginosa.

Materials and methods: Crystal violet assay and scanning electron microscopy (SEM) were used to evaluate the effect of extracts on biofilm formation and measurements of the absorbance at 600?nm to assess bacterial growth. Selected extracts were investigated regarding the cytotoxicity by MTT assay using mammal cells and the qualitative phytochemical fingerprint by thin layer chromatography.

Results: Harpochilus neesianus Mart. ex Nees. (Acanthaceae) leaves, Apuleia leiocarpa Vogel J. F. Macbr. (Fabaceae), and Poincianella microphylla Mart. ex G. Don L. P. Queiroz (Fabaceae) fruits showed non-biocidal antibiofilm action against S. epidermidis with activities of 69, 52, and 63%, respectively. SEM confirmed that biofilm structure was strongly prevented and that extracts promoted overproduction of the matrix and/or bacterial morphology modification. Poincianella microphylla demonstrated toxicity at 4.0?mg/mL and 2.0?mg/mL, A. leiocarpa presented toxicity only at 4.0?mg/mL, whereas H. neesianus presented the absence of toxicity against Vero cell line. Preliminary phytochemical analysis revealed the presence of flavonoids, terpenoids, steroids, amines, and polyphenols.

Discussion and conclusions: This work provides a scientific basis which may justify the ethnopharmacological use of the plants herein studied, indicating extracts that possess limited mammal cytotoxicity in vitro and a high potential as a source of antibiofilm drugs prototypes.     

Antioxidant,antihyperuricemic and xanthine oxidase inhibitory activities of Hyoscyamus reticulatus

Context:?Xanthine oxidase (XO) is a key enzyme in the pathophysiological homeostasis of hyperuricemia. It catalyzes the oxidation of hypoxanthine to xanthine and then to uric acid, the reaction involves the formation of free radical intermediates and superoxide byproducts.

Objectives:?This study was undertaken to investigate the antioxidant, antihyperuricemic, and xanthine oxidase inhibitory potentials of Hyoscyamus reticulatus L. (Solanaceae) extract.

Materials and methods:?The antioxidant potency was measured using the ABTS^?+ scavenging capacity system, which includes Trolox as a standard. The xanthine oxidase inhibitory activity of the extract was quantitated in vitro by measuring the decline in the catalytic rate of xanthine oxidase following incubations with the plant extracts and using xanthine as a substrate. The hypouricemic potential of the extract was evaluated using an in vivo model for hyperuricemia. We tested three different doses of the extract and allopurinol was used as standard antihyperuricemic positive control.

Results:?H. reticulatus aqueous extract exhibited significant antioxidant scavenging properties (533.26 μmol TE/g dry extract weight) and inhibitory effect on xanthine oxidase activity (IC₅₀ 12.8 μg/mL). Furthermore, oral administration of the aqueous extract significantly reduced serum urate levels in oxonate-induced hyperuricemic mice in a dose-dependent manner.

Discussion and conclusion:?Our results suggest that the aqueous extract of H. reticulatus aerial parts might have great potential as an antioxidant and a hypouricemic agent. Our lab is currently identifying the active compounds in the extract to which the biological activities could be attributed.     

Plants used to treat skin diseases in northern Maputaland,South Africa: antimicrobial activity and in vitro permeability studies

Context: Ethnobotanical claims of medicinal plants used in northern Maputaland are limited.

Objectives To establish scientific validity for a selection of the plants used in Maputaland to treat skin diseases.

Materials and methods: Aqueous and dichloromethane–methanol extracts were prepared from 37 plant species which were collected from four rural communities in Maputaland. Antimicrobial screening was performed on extracts against 12 dermatological relevant pathogens using the micro-titre plate dilution assay. Their combined effect was evaluated by determining the sum of the fractional inhibitory concentrations (ΣFICs). Chemical analysis was undertaken using reverse-phase high-performance liquid chromatography (RP-HPLC) and investigated in vitro across excised intact porcine skin using the ILC07 automated system.

Results: The organic extract of Garcinia livingstonei T. Anderson (Clusiaceae) was found to be the most antimicrobially active displaying an average broad-spectrum MIC value of 270?μg/mL. The combination of Sclerocarya birrea (A. Rich.) Hotsch. (Anacardaceae) with Syzygium cordatum Hochst. ex C. Krauss (Myrtaceae) displayed synergistic effects. The four antimicrobially active organic extracts were found to possess mainly anthraquinones, flavonoids, tannins and saponins. The organic extracts of Kigelia africana (Lam.) Benth. (Bignoniaceae) and S. cordatum were found to have more compounds capable of permeating intact skin after 10?min of exposure.

Conclusion: More than 80% of the organic extracts tested displayed a correlation between the antimicrobial efficacy and the reported traditional uses of the plants. Furthermore, the traditional use of topically applied plant preparations is validated as some compounds from the active plants are capable of permeating the skin in vitro.     

Methyl-N-methylanthranilate,a pungent compound from Citrus reticulata Blanco leaves

Context: More analgesic compounds are needed in medicine against pain since the available drugs displayed secondary effects. Natural products are a source of molecules to develop new analgesics, using the information of plants, applied against pain, with effects such as pungency, tingling, and needle, due to their possible role in the central nervous system (NCS). Citrus reticulata Blanco (Rutaceae) leaves are usually bitten to flavor the mouth and possess this type effect in lips and tongues; due to this fact the structure of the bioctive compound could be the source of other types of analgesics.

Objective: The objective of this study is to determine the causal agent of the pungent effect in mandarin essential oil.

Materials and methods: Mandarin essential oil was obtained and then purified by column chromatography. Each fraction was tested and pungency was detected only in the first fraction which was pure.

Results: The compound responsible for the pungency in the essential oils of leaves from Citrus reticulata (mandarin) was purified and the structure was assigned as methyl-N-methylanthranilate, on the basis of NMR 1D and 2D and MS. This substance corresponds to another type of molecule involving an antinociceptive effect.

Conclusions: Terpenes are compounds found in essential oils. The compound responsible for the pungency of mandarin and other citrus leaves was isolated, and surprisingly it was identified as a methyl-N-methylanthranilate. This kind of molecules with this activity could be used to discover new analgesics in human therapy against pain.     

Antioxidant and anti-inflammatory activities of Pittocaulon species from México

Context: Stems and leaves of Pittocaulon spp. (Asteraceae) are used in Mexican traditional medicine as an anti-inflammatory substance and for the treatment of skin injuries.

Objective: This study evaluated the antioxidant activity of methanol (MeOH) and dichloromethane (DC) extracts of five Pittocaulon species.

Materials and methods: DC and MeOH extracts from flowers, roots, and stems of Pittocaulon praecox (Cav.) H. Rob. & Brettell, P. bombycophole (Bullock) H. Rob. & Brettell, P. filare (Mc Vaugh) H. Rob. & Brettell, P. velatum (Greenm.) Rob. & Brettell and P. hintonii H. Rob. & Brettell.

Result and Discussion: In the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, the flower extracts obtained with MeOH were the most active with IC₅₀ values ranging from 51.83?±?4.08 to 154.19?±?8.39 ppm. In the thiobarbituric acid reactive substances (TBARS) model, the best activity was shown by DC extracts of roots with IC₅₀ values ranging from 55.54?±?1.28 to 160.82?±?5.37 ppm. The MeOH extract of flowers of P. bombycophole had the highest IC₅₀ value in both DPPH (51.83?±?4.08 ppm) and TBARS (39.78?±?1.97 ppm). The samples with the best values in the antioxidant activity assays were evaluated in the anti-inflammatory tests. The DC root extract of P. velatum at a dose of 1?mg/ear produced the greatest reduction (84.96%) of the 2-O-tetradecanoylphorbol-13-acetate (TPA)-induced mouse ear edema. This extract also reduced the activity of the enzyme myeloperoxidase (MPO) (73.65%) at the same dose. In contrast, DC root extract of this species did not show significant inhibition of the increase in paw edema induced by carrageenan at the doses tested (100?mg/kg).

Conclusion: These results support the traditional use of these plants as anti-inflammatory. DC extracts of P. velatum and MeOH extracts of P. bombycophole may be a potential resource of natural anti-inflammatory and antioxidant compounds, respectively. Additional studies must be done to identify the compounds responsible of the activity on these plants and to establish the mechanism of action.     

Biological activities of ethyl acetate extract of different parts of Hyssopus angustifolius

Context: Hyssopus angustifolius M. Bieb. (Lamiaceae) is one of the most important medicinal plants in Iranian traditional medicine for the treatment of lung inflammation, laryngitis and cough relief. Much attention has been paid to this medicinal plant because of its traditional uses.

Objective: The present study examined the antioxidant and antihemolytic activities of ethyl acetate extract of stems, leaf and flowers of Hyssopus angustifolius.

Materials and methods: Antioxidant activity of extracts was evaluated by employing six different models, i.e., DPPH, nitric oxide and hydrogen peroxide scavenging, metal chelating and reducing power activities and hemoglobin-induced linoleic acid system. Also, antihemolytic activity was evaluated against hydrogen peroxide-induced hemolysis.

Results: Flowers extract showed the better activity than leaf and stems extracts in DPPH radical scavenging activity (IC₅₀ was 275.4?±?7.6 μg mL^?1). Leaf, stems and flowers extracts showed good nitric oxide scavenging activity (IC₅₀ were 376.6?±?11.4 µg mL^?1 for flowers, 297.6?±?9.6 μg mL^?1 µg mL^?1 for leaves and 837.8?±?19.2 µg mL^?1 for stems). The leaf extract exhibited better hydrogen peroxide scavenging and Fe²⁺ chelating activity than stems and flowers extracts. In hemoglobin-induced linoleic acid system, all of the extracts exhibited very good activity. Also, extracts show weak reducing power activity. The ethyl acetate extract of leaf showed better antihemolytic activity than the flower and stems (IC₅₀ was 94.0?±?2.4 μg mL^?1).

Discussion and conclusion: These findings give a scientific basis to the traditional usage of Hyssopus angustifolius, also showing its potential as rich sources of natural antioxidant compounds.     

Effects of Catuaba extracts on microbial and HIV infection.

Pretreatment of mice with hot water and alkaline extracts of Catuaba casca (Erythroxylum catuaba Arr. Cam.) effectively protected them from lethal infection of Escherichia coli and Staphylococcus aureus. The extracts significantly inhibited both the human immunodeficiency virus (HIV)-induced cytopathic effect and the expression of HIV antigen in HIV-1HTLV-IIIB or HIV-2ROD infected human lymphotropic virus type I (HTLV-1) positive MT-4 cells. The 50% effective concentrations of the active fractions (21-263 micrograms/ml) were 1/4 - 1/43 of their 50% cytotoxic concentrations. Their anti-HIV activity was shown to be induced, at least in part, via the inhibition of HIV adsorption to the cells. The data suggest a medicinal potential of Catuaba extracts against opportunistic infection in HIV patients.     

Secondary metabolites that could contribute to the monodominance of Erythrina fusca in the Brazilian Pantanal

Erythrina fusca is a dominant species in the Brazilian Pantanal. We hypothesized that E. fusca possess allelopathic potential and we evaluated effects of extracts on germination and development of Lactuca sativa, a bioindicator species. We tested the effect of leaves, bark, roots, and seeds extracts of E. fusca on germination and speed index, using high, moderate and low concentration (0.2, 1 and 5 mg mL^–1). To evaluate effects on development, we subjected seedlings of L. sativa to the same treatments and measured root and aerial part length. High concentration of extracts reduced L. sativa germination; leaves extract caused the maximum reduction on germination of L. sativa, similar to 2,4-Dichlorophenoxyacetic acid (2,4-D); this extract has flavonoids and saponins as main compounds, classes that also occur in the bark and roots extracts in lower concentrations; bark and roots (5 mg mL^–1), leaves and roots (1 mg mL^–1) decreased these traits as well, but in lower magnitude. A significant reduction in root length was induced by highest concentration of all extracts (5 mg mL^–1); the results suggest that erythrinic alkaloids should interfere in the root length once the seeds accumulate almost exclusively this class of compounds. Our results showed that all parts of E. fusca had adverse effects on germination or development of L. sativa, showing that different class of compounds secondary metabolites is involved in this activity. Possibly, this phytotoxicity influences monodominance of E. fusca in Pantanal, but studies are essential to evaluate effects of it on other native species.