Background and Aims
Silymarin, an extract from the seeds of the milk thistle plant Silybum marianum, has been used for centuries for the treatment of chronic liver diseases. Despite common use by patients with hepatitis C in the U.S., its clinical efficacy remains uncertain. The goal of this study was to determine if silymarin has in vitro effects on immune function that might have implications for its potential effect on HCV-induced liver disease.
Freshly isolated PBMC and T cells from HCV-infected and uninfected subjects were tested in vitro for responses to nonspecific and antigenic stimulation in the presence and absence of a standardized preparation of silymarin (MK001).
Minimal MK001 toxicity on PBMC was found at concentrations between 5-40 μg/mL. MK001 dose-dependently inhibited the proliferation and secretion of TNF-α, IFN-γ, and IL-2 by PBMC stimulated with anti-CD3. In addition, MK001 inhibited proliferation by CD4+ T cells to HCV, Candida and Tetanus protein antigens, and by HLA-A2/HCV1406-1415-specific CD8+ T cells to allogeneic stimulation. MK001 inhibited T cell TNF-α and IFN-γ cytokine secretion to Tetanus and Candida protein antigens. Finally, MK001 inhibited NF-κB transcriptional activation after T cell receptor-mediated stimulation of Jurkat T cells, consistent with its ability to inhibit Jurkat T cell proliferation and secretion of IL-2.
Silymarin’s ability to inhibit the proliferation and pro-inflammatory cytokine secretion of T cells, combined with its previously described anti-viral effect suggests a possible mechanism of action that could lead to clinical benefit during HCV infection.
Milk thistle; Silybum marianum; Silymarin; Silibinin; Immune; T cell; Hepatitis C; HCV; Anti-inflammatory; Proliferation; Cytokine
Salvinorin A (1), the main active ingredient of Salvia divinorum, is a potent and selective κ opioid receptor (KOPR) agonist. Based on the SAR, its C-2 position is one of the key binding sites and has very little space tolerance (3–4 carbons atoms) and limited to only lipophilic groups. In our attempt to prepare PET brain imaging agent for mapping KOPR, a series of C-2 halogenated analogs have been synthesized and screened for binding affinity at κ(KOPR), μ(MOPR), and δ (DOPR). These C-2 halogenated analogs with sequential changes of atomic radius and electron density serve as excellent molecular probes for further investigating the binding pocket at C-2, particularly on the effects of α verses β configuration at C-2 position. The results of KOPR binding and functional studies reveal β isomer in general binds better than α isomer with the exception of iodinated analogs and none of the C-2 halogenated analogs shows any improvement of KOPR binding affinity. Interestingly, functional assay has characterized that 6b is a partial agonist with Emax of 46% of the kappa receptor full agonist U50,488H at 250 nM (Ki). We have also observed that the affinity to the kappa receptor increases with atomic radius (I > Br > Cl > F) which is in good agreement with halogen bonding interactions reported in the literature.
Salvinorin A; Kappa; Halogenation
We previously reported isolation of l-isocorypalmine
(l-ICP), a mono-demethylated analog of
l-tetrahydropalmatine (l-THP), from
the plant Corydalis yanhusuo. Here we characterized its
in vitro pharmacological properties and examined its
effects on cocaine-induced behaviors in mice.
Receptor binding, cAMP and
[35S]GTPγS assays were used to examine
pharmacological actions of l-ICP in vitro.
Effects of I-ICP on cocaine-induced locomotor hyperactivity
and sensitization and conditioned place preference (CPP) in mice were
investigated. HPLC was employed to analyze metabolites of
I-ICP in mouse serum.
Among more than 40 targets screened, l-ICP and
l-THP bound only to dopamine (DA) receptors.
l-ICP was a high-affinity partial agonist of D1 and D5
receptors and a moderate-affinity antagonist of D2, D3 and D4 receptors,
whereas l-THP bound to only D1 and D5 receptors, with lower
affinities than l-ICP. At 10 mg/kg (i.p.),
l-ICP inhibited spontaneous locomotor activity for a
shorter time than l-THP. Pretreatment with
l-ICP reduced cocaine-induced locomotor
hyperactivities. Administration of l-ICP before cocaine
once a day for 5 days reduced cocaine-induced locomotor sensitization on
days 5 and 13 after 7 days of withdrawal. Pretreatment with
l-ICP before cocaine daily for 6 days blocked
cocaine-induced CPP, while l-ICP itself did not cause
preference or aversion. HPLC analysis showed that l-ICP was
the main compound in mouse serum following i.p. injection of
l-ICP likely acts as a D1 partial agonist and a D2
antagonist to produce its in vivo effects and may be a
promising agent for treatment of cocaine addiction.
tetrahydropalmatine; isocorypalmine; cocaine; conditioned place preference; sensitization; dopamine receptor
Whereas adipocytes have a unique capacity to store excess free fatty acids in the form of triglyceride in lipid droplets, non-adipose tissues, such as liver, have a limited capacity for storage of lipids. Saturated long-chain fatty acids, such as palmitate, are the major contributors to lipotoxicity. Silymarin is a mixture of flavonolignans, extracted from the milk thistle (Silibum marianum). Its hepatoprotective properties have been studied both in vitro and in vivo; however, its effect on palmitate-induced lipotoxicity has not been investigated. The objective of this study was to investigate (i) whether silymarin could protect HepG2 cells from palmitate-induced cell death in an in vitro model, and (ii) possible mechanisms involved in this hepatoprotective role of silymarin. HepG2 cells were treated with palmitate in the absence or presence of silymarin and supernatants or cell lysates were collected at varying time-points. Cell death was assayed by measuring DNA fragmentation, caspase-3 activity and lactate dehydrogenase release. Lipid peroxidation was assessed by measuring malondialdehyde and 4-hydroxyalkenals. Akt kinase activity was also measured. Incubation with palmitate caused significant death in HepG2 cells. Palmitate incubation did not cause significant changes in reactive oxygen species production or intracellular glutathione content, but markedly inhibited Akt kinase activity. Pre-treatment of HepG2 cells with silymarin prevented palmitate-induced inhibition of Akt kinase activity and attenuated cell death. Our results suggest that silymarin may be an effective agent in protecting hepatocytes from saturated fatty acids-induced cell death. These data also provide a further rationale for exploration of the use of silymarin in the treatment of non-alcoholic steatohepatitis.
Accumulated evidence has demonstrated that both oxidative stress and abnormal cytokine production, especially tumor necrosis factor-α (TNF), play important etiological roles in the pathogenesis of alcoholic liver disease (ALD). Agents that have both antioxidant and anti-inflammation properties, particularly anti-TNF production, represent promising therapeutic interventions for ALD. We investigated the effects and the possible mechanism(s) of silymarin on liver injury induced by acute ethanol (EtOH) administration.
Nine-week-old mice were divided into 4 groups, control, silymarin treatment, EtOH treatment, and silymarin/EtOH treatment, with 6 mice in each group. Because control and silymarin values were virtually identical, only control treatment is shown for ease of viewing. Ethanol-treated mice received EtOH [5 g/kg body weight (BW)] by gavage every 12 hours for a total of 3 doses. Control mice received an isocalorical maltose solution. In the silymarin/EtOH group, silymarin was dissolved in the EtOH and gavaged simultaneously with EtOH at a dose of 200 mg/kg BW. At 4 hours after the last dosing, the mice were anesthetized and subsequent serum alanine aminotransferase (ALT) level, hepatic lipid peroxidation, enzymatic activity of hepatic cytochrome P450 2E1, hepatic TNF-α, and glutathione (GSH) levels were measured. Histopathological change was assessed by hematoxylin and eosin staining.
Acute EtOH administration caused prominent hepatic microvesicular steatosis with mild necrosis and an elevation of serum ALT activity, induced a significant decrease in hepatic GSH in conjunction with enhanced lipid peroxidation, and increased hepatic TNF production. Supplementation with a standardized silymarin attenuated these adverse changes induced by acute EtOH administration.
Silymarin protects against the liver injury caused by acute EtOH administration. In view of its nontoxic nature, it may be developed as an effective therapeutic agent for alcohol-induced liver disease by its antioxidative stress and anti-inflammatory features.
Silymarin; Ethanol; Oxidative Stress; Liver Injury; Glutathione; CYP2E1; TNF
We previously demonstrated that short-term treatment with a standardized kudzu extract (NPI-031) reduced alcohol drinking by men and women in a natural setting. The present study was conducted in non treatment-seeking heavy drinkers to assess the safety and efficacy of four weeks of kudzu extract in an outpatient setting.
This randomized between-subject, double-blind, placebo-controlled study involved two weeks of baseline, four weeks of treatment and two weeks of follow-up. Seventeen men (21–33 years) who reported drinking 27.6 ± 6.5 drinks/week with a diagnosis of alcohol abuse/dependence took either kudzu extract (250 mg isoflavones, t.i.d.) or matched placebo on a daily basis. They reported alcohol consumption and desire to use alcohol using a wrist actigraphy device; twice weekly laboratory visits were scheduled to monitor medication adherence and adverse events.
Medication adherence was excellent and there were no adverse events, changes in vital signs, blood chemistry, renal or liver function. There was no effect on alcohol craving, but kudzu extract significantly reduced the number of drinks consumed each week by 34–57%, reduced the number of heavy drinking days and significantly increased the percent of days abstinent and the number of consecutive days of abstinence.
A standardized formulation of kudzu extract produced minimal side effects, was well-tolerated and resulted in a modest reduction in alcohol consumption in young non treatment-seeking heavy drinkers. Additional studies using treatment-seeking alcohol-dependent persons will be necessary to determine the usefulness of this herbal preparation in reducing alcohol use in other populations.
Isoflavone compounds naturally occurring in the root of the kudzu plant have been used historically to treat alcohol-related problems. A pilot study was conducted to assess the effects of one primary isoflavone - puerarin- for its ability to modify alcohol intake in humans.
Ten (10) healthy adult volunteers were administered puerarin (1200 mg daily) in a double-blind, placebo-controlled, crossover design experiment for one week prior to an afternoon drinking session lasting 1.5 hours. Participants had access to up to six bottles of their preferred brand of beer in addition to juice and water. A time course of drinking, sip volumes, and total amount consumed were recorded.
Participants consumed on average 3.5 (± 0.55) beers when treated with placebo and 2.4 (± 0.41) beers when treated with puerarin. In contrast to drinking following placebo treatment when 3 participants drank 5 beers and 1 participant drank all 6 beers, none drank 5 or 6 beers when treated with puerarin. Drinking topography also changed. When treated with puerarin, participants decreased sip size, took more sips to finish a beer, and took longer to consume each beer. Additionally, after finishing a beer, latency to opening the next beer was increased.
This study is the first demonstration that a single isoflavone found in the kudzu root can alter alcohol drinking in humans. These results suggest that alcohol consumption patterns are influenced by puerarin administration and this botanical medication may be a useful adjunct in the treatment of excessive alcohol intake.
isoflavone; alcohol consumption; binge drinking; humans
Rheumatoid arthritis (RA) is a chronic inflammatory disease of autoimmune origin. Huo-luo-xiao-ling dan (HLXL) is an herbal mixture that has been used in traditional Chinese medicine over several decades to treat chronic inflammatory diseases including RA. However, the mechanism of the anti-arthritic action of this herbal remedy is poorly understood at the molecular level. In this study, we determined by microarray analysis the effects of HLXL on the global gene expression profile of the draining lymph node cells (LNC) in the rat adjuvant arthritis (AA) model of human RA. In LNC restimulated in vitro with the disease-related antigen mycobacterial heat-shock protein 65 (Bhsp65), 84 differentially expressed genes (DEG) (64 upregulated and 20 downregulated) versus 120 DEG (94 upregulated and 26 downregulated) were identified in HLXL-treated versus vehicle (Water)-treated rats, respectively, and 62 DEG (45 upregulated and 17 downregulated) were shared between the two groups. The most affected pathways in response to HLXL treatment included immune response, inflammation, cellular proliferation and apoptosis, and metabolic processes, many of which are directly relevant to arthritis pathogenesis. These results would advance our understanding of the mechanisms underlying the anti-arthritic activity of HLXL.
Huo-luo-xiao-ling dan (HLXL) is an herbal mixture that has long been used in traditional Chinese medicine for the treatment of rheumatoid arthritis (RA) and other inflammatory disorders. Despite the availability of potent conventionally used drugs for RA, their limited efficacy in a proportion of patients coupled with their high cost and severe adverse effects has necessitated the search for novel therapeutics for this debilitating disease. Further, the control of both inflammation and bone damage is essential for effective management of arthritis. The aim of our study was to evaluate the efficacy of HLXL against arthritic bone damage in adjuvant arthritis (AA) model of RA. Our results show that HLXL treatment suppressed inflammatory arthritis and reduced bone and cartilage damage in the joints of arthritic Lewis rats. HLXL-induced protection against bone damage was mediated primarily via inhibition of mediators of osteoclastic bone remodeling (e.g., receptor activator of nuclear factor kappa-B ligand; RANKL), skewing of RANKL/osteoprotegerin (OPG) ratio in favor of antiosteoclastic activity, reduction in the number of osteoclasts in the arthrodial joint's bone, and inhibition of cytokine production and MMP activity. Our results suggest that HLXL might offer a promising alternative/adjunct treatment for both inflammation and bone damage in RA.
Transcutaneous electric acupoint stimulation (TEAS) avoids the use of needles, and instead delivers a mild electric current at traditional acupoints. This technique has been used for treating heroin addiction, but has not been systematically tested for other drugs of abuse. This study aims to investigate the effects of TEAS on drug addiction.
Volunteers who were either cocaine-dependent (n = 9) or cannabis-dependent (n = 11) but were not seeking treatment for their dependence participated in a within-subject, single-blind study. Treatment consisted of twice daily 30-minute sessions of TEAS or sham stimulation for 3.5 days. The active TEAS levels were individually adjusted to produce a distinct twitching response in the fingers, while the sham stimulation involved 2 minutes of stimulation at threshold levels followed by 28 minutes of stimulation below the detection levels. The participants recorded their drug use and drug cravings daily. At 1 hour after the last morning session of TEAS or sham stimulation, a cue-induced craving EEG evaluation was conducted. Event-related P300 potentials (ERPs) were recorded, sorted, and analyzed for specific image types (neutral objects, non-drug-related arousing images, or drug-related images).
TEAS treatment did not significantly reduce the drug use or drug cravings, or significantly alter the ERP peak voltage or latency to peak response. However, the TEAS treatment did significantly modulate several self-reported measures of mood and anxiety.
The results of this pilot study with a limited sample size suggest that the acupoint stimulation techniques and protocol used in this trial alone do not significantly reduce cravings for or use of cocaine or cannabis. The findings that TEAS modulates mood and anxiety suggest that TEAS could be used as an adjunct in a multimodal therapy program to treat cocaine and cannabis dependence if confirmed in a full randomized controlled clinical trial.
Rheumatoid arthritis (RA) is a chronic inflammatory disease affecting the joints that can lead to deformities and disability. The prolonged use of conventionally used drugs is associated with severe adverse reactions. Therefore, safer and less expensive therapeutic products are continually being sought. Huo-Luo-Xiao-Ling dan (HLXL), a traditional Chinese herbal mixture, and its modified versions possess anti-arthritic activity. In this paper, we examined the influence of modified HLXL on two of the key mediators of arthritic inflammation and tissue damage, namely, chemokines and matrix-metalloproteinases (MMPs) in the rat adjuvant-induced arthritis (AA) model of RA. We treated arthritic Lewis rats with HLXL (2.3 g/kg) by daily gavage beginning at the onset of AA. The control rats received the vehicle. At the peak phase of AA, rats were sacrificed and their draining lymph node cells (LNC) and spleen adherent cells (SAC) were tested. The HLXL-treated rats showed a significant reduction in the levels of chemokines (RANTES, MCP-1, MIP-1α, and GRO/KC), MMPs (MMP 2 and 9), as well as cytokines (IL-6 and IL-17) that induce them, compared to the control vehicle-treated rats. Thus, HLXL controls arthritis in part by suppressing the mediators of immune pathology, and it might offer a promising alternative/adjunct treatment for RA.
Salvinorin A is a naturally-occurring potent and selective kappa opioid receptor agonist, and smoking salvinorin A produces the most intense hallucinogenic effects in human. Eight neoclerodane diterpene derivatives were isolated from the smoke of salvinorin A, and their structures were identified by spectroscopic methods. The major structural changes include epimerizations, eliminations, and rearrangements.
Salvinorin A; Neoclerodane diterpenoid; Smoke; Opioid receptor
The high rate of HIV-1 mutation and the frequent sexual transmission highlight the need for novel therapeutic modalities with broad activity against both CXCR4 (X4) and CCR5 (R5)-tropic viruses. We investigated a large number of natural products, and from Sargassum fusiforme we isolated and identified palmitic acid (PA) as a natural small bioactive molecule with activity against HIV-1 infection. Treatment with 100 μM PA inhibited both X4 and R5 independent infection in the T cell line up to 70%. Treatment with 22 μM PA inhibited X4 infection in primary peripheral blood lymphocytes (PBL) up to 95% and 100 μM PA inhibited R5 infection in primary macrophages by over 90%. Inhibition of infection was concentration dependent, and cell viability for all treatments tested remained above 80%, similar to treatment with 10−6 M nucleoside analogue 2′, 3′-dideoxycytidine (ddC). Micromolar PA concentrations also inhibited cell-to-cell fusion and specific virus-to-cell fusion up to 62%. PA treatment did not result in internalization of the cell surface CD4 receptor or lipid raft disruption, and it did not inhibit intracellular virus replication. PA directly inhibited gp120-CD4 complex formation in a dose-dependent manner. We used fluorescence spectroscopy to determine that PA binds to the CD4 receptor with Kd ∼1.5 ± 0.2 μM, and we used one-dimensional saturation transfer difference NMR (STD-NMR) to determined that the PA binding epitope for CD4 consists of the hydrophobic methyl and methelene groups located away from the PA carboxyl terminal, which blocks efficient gp120-CD4 attachment. These findings introduce a novel class of antiviral compound that binds directly to the CD4 receptor, blocking HIV-1 entry and infection. Understanding the structure–affinity relationship (SAR) between PA and CD4 should lead to the development of PA analogs with greater potency against HIV-1 entry.
Rheumatoid arthritis (RA) is one of the major autoimmune diseases of global prevalence. The use of the anti-inflammatory drugs for the treatment of RA is associated with severe adverse reactions and toxicity. This limitation has necessitated the search for novel therapeutic products. We report here a traditional Chinese medicine-based herbal formula, Huo luo xiao ling dan (HLXL), which has potent antiarthritic activity as validated in the rat adjuvant-induced arthritis (AA) model. HLXL (2.3 g/Kg) was fed to Lewis (RT.11) rats daily by gavage beginning at the onset of arthritis and then continued through the observation period. HLXL inhibited the severity of ongoing AA. This suppression of arthritis was associated with significant alterations in the T cell proliferative and cytokine responses as well as the antibody response against the disease-related antigen, mycobacterial heat-shock protein 65 (Bhsp65). There was a reduction in the level of the proinflammatory cytokines IL-17 and IL-1β but enhancement of the anti-inflammatory cytokine IL-10 level. In addition, there was inhibition of both the anti-Bhsp65 antibody response and the serum level of nitric oxide. Thus, HLXL is a promising CAM modality for further testing in RA patients.
HLXL is a traditional Chinese medicine that has long been used in folk medicine for the treatment of chronic inflammatory diseases. However, the precise immunological mechanisms by which HLXL mediates its anti-inflammatory activity are not fully defined.
Aim of the study
To determine the effects of HLXL on antigen-specific immune parameters in adjuvant-induced inflammation model in the Lewis rat.
Materials and Methods
Rats were fed daily with either HLXL (2.3 g/kg) or vehicle (water) beginning 3 d before subcutaneous injection of heat-killed M. tuberculosis H37Ra (Mtb), and then continued for another 6 d. After 9 d of Mtb injection, the draining lymph node cells were tested for T cell proliferative and cytokine responses against mycobacterial heat-shock protein 65 (Bhsp65). Moreover, sera were tested for anti-Bhsp65 antibodies and nitric oxide (NO).
HLXL-treated rats showed reduced T cell proliferative response to Bhsp65 compared to control rats. Furthermore, HLXL suppressed IL-17 response but enhanced IL-10 response without much effect on IFN-γ. HLXL treatment also reduced the levels of anti-Bhsp65 antibodies but not that of NO.
HLXL feeding modulated both the cellular and the humoral immune response to Bhsp65 favoring an anti-inflammatory milieu for suppression of adjuvant-induced inflammation.
Huo-Luo-Xiao-Ling Dan; Immune modulation; Cytokines; Antibodies; T cells; Inflammation
We recently reported that palmitic acid (PA) is a novel and efficient CD4 fusion inhibitor to HIV-1 entry and infection. In the present report, based on in silico modeling of the novel CD4 pocket that binds PA, we describe discovery of highly potent PA analogs with increased CD4 receptor binding affinities (Kd) and gp120-to-CD4 inhibition constants (Ki). The PA analogs were selected to satisfy Lipinski's rule of drug-likeness, increased solubility, and to avoid potential cytotoxicity.
PA analog 2-bromopalmitate (2-BP) was most efficacious with Kd ∼74 nM and Ki ∼122 nM, ascorbyl palmitate (6-AP) exhibited slightly higher Kd ∼140 nM and Ki ∼354 nM, and sucrose palmitate (SP) was least efficacious binding to CD4 with Kd ∼364 nM and inhibiting gp120-to-CD4 binding with Ki ∼1486 nM. Importantly, PA and its analogs specifically bound to the CD4 receptor with the one to one stoichiometry.
Considering observed differences between Ki and Kd values indicates clear and rational direction for improving inhibition efficacy to HIV-1 entry and infection. Taken together this report introduces a novel class of natural small molecules fusion inhibitors with nanomolar efficacy of CD4 receptor binding and inhibition of HIV-1 entry.
Bioactivity-guided fractionation of Notopterygium forbesii has resulted in the isolation of one new coumarin glycoside and one new phenethyl vanillate, together with seventeen known compounds. The structures of these compounds were characterized by spectroscopic methods. These compounds were evaluated for their binding affinities to the opioid and dopamine receptors, and falcarindiol showed weak binding affinities to opioid receptors and moderate affinity for D1 receptor (Ki = 192±6 nM).
Notopterygium forbesii; Coumarin; Falcarindiol; Opioid receptor; Dopamine receptor
To unambiguously confirm the actual product in autoxidation of salvinorin A under basic conditions, deacetyl-1,10-didehydrosalvinorin G was synthesized from salvinorin C via intermediate salvinorin H. Furthermore, oxidation of salvinorin D with manganese dioxide gave salvinorin G in good yield.
Salvinorin A; Oxidation; Manganese dioxide; Synthesis
Salvinorin (Sal) A is a naturally occurring, selective κ opioid receptor (KOPR) agonist with a short duration of action in vivo. Pharmacological properties of a C(2) derivative, 2-methoxy-methyl (MOM)-Sal B, were characterized. MOM-Sal B bound to KOPR with high selectivity and displayed ~3-fold higher affinity than U50,488H [(trans)-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)-cyclohexyl]benzeneacetamide methanesulfonate] and Sal A. It acted as a full agonist at KOPR in guanosine 5′-O-(3-[35S]thio)triphosphate binding and was ~5- and ~7-fold more potent than U50,488H and Sal A, respectively. In Chinese hamster ovary cells stably expressing KOPR, all three κ agonists internalized or down-regulated KOPR to similar extents, with MOM-Sal B being the most potent. In mice, MOM-Sal B (0.05–1 mg/kg s.c.) caused immediate and dose-dependent immobility lasting ~3 h, which was blocked by norbinaltorphimine. In contrast, ambulation in a Y-maze was increased when rats received MOM-Sal B (1–5 mg/kg s.c.). In addition, MOM-Sal B (0.5–5 mg/kg i.p.) produced antinociception (hot-plate test) and hypothermia in a dose-dependent manner in rats. MOM-Sal B was more potent than U50,488H in both tests and more efficacious than U50,488H in the hot-plate test. These latter two in vivo effects were blocked by norbinaltorphimine, indicating KOPR-mediated actions. Sal A at 10 mg/kg elicited neither antinociception nor hypothermia 30 min after administration to rats. In summary, MOM-Sal B is a potent and efficacious KOPR agonist with longer lasting in vivo effects than Sal A.
In comparison with the NMR data of salvinorin A and its 8-epimer, the published structure of deacetyl-1,10-didehydrosalvinorin G was revised to its 8-epimer. The stereochemistry of 8-epi-deacetyl-1,10-didehydrosalvinorin G was further confirmed by NOESY and chemical synthesis.
Salvinorin A; Epimer; NMR; Revised structure
The high rate of HIV-1 mutation and increasing resistance to currently available antiretroviral (ART) therapies highlight the need for new antiviral agents. Products derived from natural sources have been shown to inhibit HIV-1 replication during various stages of the virus life cycle, and therefore represent a potential source of novel therapeutic agents. To expand our arsenal of therapeutics against HIV-1 infection, we investigated aqueous extract from Sargassum fusiforme (S. fusiforme) for ability to inhibit HIV-1 infection in the periphery, in T cells and human macrophages, and for ability to inhibit in the central nervous system (CNS), in microglia and astrocytes.
S. fusiforme extract blocked HIV-1 infection and replication by over 90% in T cells, human macrophages and microglia, and it also inhibited pseudotyped HIV-1 (VSV/NL4-3) infection in human astrocytes by over 70%. Inhibition was mediated against both CXCR4 (X4) and CCR5 (R5)-tropic HIV-1, was dose dependant and long lasting, did not inhibit cell growth or viability, was not toxic to cells, and was comparable to inhibition by the nucleoside analogue 2', 3'-didoxycytidine (ddC). S. fusiforme treatment blocked direct cell-to-cell infection spread. To investigate at which point of the virus life cycle this inhibition occurs, we infected T cells and CD4-negative primary human astrocytes with HIV-1 pseudotyped with envelope glycoprotein of vesicular stomatitis virus (VSV), which bypasses the HIV receptor requirements. Infection by pseudotyped HIV-1 (VSV/NL4-3) was also inhibited in a dose dependant manner, although up to 57% less, as compared to inhibition of native NL4-3, indicating post-entry interferences.
This is the first report demonstrating S. fusiforme to be a potent inhibitor of highly productive HIV-1 infection and replication in T cells, in primary human macrophages, microglia, and astrocytes. Results with VSV/NL4-3 infection, suggest inhibition of both entry and post-entry events of the virus life cycle. Absence of cytotoxicity and high viability of treated cells also suggest that S. fusiforme is a potential source of novel naturally occurring antiretroviral compounds that inhibit HIV-1 infection and replication at more than one site of the virus life cycle.
Traditional herbal formulas used to treat inflammatory arthritis in China and India include Boswellia carterii or Boswellia serrata. They both contain boswellic acids (BAs) which have been shown to exhibit anti-inflammatory and antiarthritic properties. This study tests the hypothesis that mixtures of BAs derived from B. carterii have immunomodulatory properties. B. carterii plant resin obtained from China was prepared as an ethanol extract, and the presence of seven BAs was confirmed by column chromatography, high-performance liquid chromatography, and UV laser desorption/ionization tandem mass spectroscopy. The extract was then tested for its ability to alter in vitro production of TH1 cytokines (interleukin-2 [IL-2] and gamma interferon) and TH2 cytokines (IL-4 and IL-10) by murine splenocytes. Delivery of the resin extract using ethanol as a solvent resulted in significant cellular toxicity not seen with the addition of ethanol alone. By contrast, delivery of the resin extract using a sesame oil solvent resulted in a dose-dependent inhibition of TH1 cytokines coupled with a dose-dependent potentiation of TH2 cytokines. These results indicate that a purified mixture of BAs from B. carterii plant resin exhibits carrier-dependent immunomodulatory properties in vitro.