Safety and efficacy of Virend for topical treatment of genital and anal herpes simplex lesions in patients with AIDS

A Review on Phytochemistry and Recent Pharmacology of Dragon's Blood (Croton lechleri), a Multifunctional Ethnomedicinal Resource from the Amazon Forest

Croton lechleri, commonly known as "Sangre de Drago", is a widely utilized ethnomedicinal resource in the Amazon region, known for its diverse bioactive properties. These include wound-healing activity, anti-inflammatory effects, antitumor activity, and other therapeutic benefits. Despite its extensive traditional use, a comprehensive review of the scientific studies conducted over the past two decades is lacking, which hinders a thorough understanding of the chemical and pharmacological characteristics of this species. Hence, this review is essential to inform researchers and readers about the current state of knowledge in this field. A systematic search was conducted using databases such as Scopus and Google Scholar, yielding 33 relevant articles focusing on the phytochemistry and recent pharmacological investigations of C. lechleri. These studies identify proanthocyanidins as the predominant phytochemical group in terms of relative quantity. Additionally, other significant phytochemical groups include alkaloids, diterpenoids, phytosteroids, saponins, phenolics, and polyphenolics. The pharmacological studies reviewed highlight several potential therapeutic effects of C. lechleri, particularly those associated with its resin. These effects include wound-healing, antitumor, anti-inflammatory, and gastrointestinal benefits, among others. The findings underscore the remarkable medicinal importance of this species, supporting its continued investigation and potential therapeutic applications.

Towards Advances in Medicinal Plant Antimicrobial Activity: A Review Study on Challenges and Future Perspectives

The increasing incidence of drug- resistant pathogens raises an urgent need to identify and isolate new bioactive compounds from medicinal plants using standardized modern analytical procedures. Medicinal plant-derived compounds could provide novel straightforward approaches against pathogenic bacteria. This review explores the antimicrobial activity of plant-derived components, their possible mechanisms of action, as well as their chemical potential. The focus is put on the current challenges and future perspectives surrounding medicinal plants antimicrobial activity. There are some inherent challenges regarding medicinal plant extracts and their antimicrobial efficacy. Appropriate and optimized extraction methodology plant species dependent leads to upgraded and selective extracted compounds. Antimicrobial susceptibility tests for the determination of the antimicrobial activity of plant extracts may show variations in obtained results. Moreover, there are several difficulties and problems that need to be overcome for the development of new antimicrobials from plant extracts, while efforts have been made to enhance the antimicrobial activity of chemical compounds. Research on the mechanisms of action, interplay with other substances, and the pharmacokinetic and/or pharmacodynamic profile of the medicinal plant extracts should be given high priority to characterize them as potential antimicrobial agents.

What We Know and What We Do Not Know about Dragon Trees?

This article is a broad review focused on dragon trees—one of the most famous groups of trees in the world, well known from ancient times. These tertiary relicts are severely endangered in most of the area where they grow. The characteristic features of the dragon tree group are described and the species belonging to this group are listed. This review gathers together current knowledge regarding the taxonomy, evolution, anatomy and morphology, physiology, and ontogeny of arborescent dragon tree species. Attention is also paid to the composition, harvesting, medicinal, and ethnobotanical use of the resin (dragons’ blood). An evaluation of population structure, distribution, ecology, threats, and nature conservation forms the final part of the review. In the conclusions we recommend further avenues of research that will be needed to effectively protect all dragon tree species.

Terpenoid profiles of resin in the genus Dracaena are species specific

Dragon's blood is the colloquial name for the red resin produced by tree species in the genus Dracaena (Asparagaceae), and the resin is directly involved in plant defensive mechanisms against pathogen and herbivore attack. It is also widely used in traditional folk medicine due to its antiviral, antimicrobial and antitumor activities. In the present work, a method using solid phase microextraction combined with two-dimensional gas chromatography with time-of-flight mass spectrometric detection was developed for the analysis of resin from five Dracaena species, namely Dracaena cinnabari Balf. f., D. serrulata Baker, D. ombet Heuglin ex Kotschy & Peyr., D. draco subsp. draco, and D. draco subsp. ajgal. Twenty terpenoid components in the resins of the five species were identified after comparative study of the volatile metabolite profiles. Monoterpenes were found to be species specific, and the observed differences might be further investigated as a possible means of identifying chemotaxonomic markers. In addition, for the first time, we describe the terpenoid volatile profiles of D. ombet and D. serrulata resins.

Extracts of Equisetum giganteum L and Copaifera reticulate Ducke show strong antiviral activity against the sexually transmitted pathogen herpes simplex virus type 2

ETHNOPHARMACOLOGICAL RELEVANCE

Equisetum giganteum L and Copaifera reticulate Ducke have been traditionally used by women of the Tacana tribe in the Bolivian Amazonas for genital hygiene and for treatment of genital infection/inflammation.

AIM OF THE STUDY

To assess the ability of extracts from Equisetum giganteum L and Copaifera reticulate Ducke to block genital viral infection by herpes simplex virus type 2.

MATERIALS AND METHODS

Equisetum giganteum L and Copaifera reticulate Ducke were collected from the Amazon region of La Paz, Bolivia. Extracts were prepared and screened for anti-viral activity against herpes simplex virus type 2 (HSV-2) using both in vitro and in in vivo models of infection.

RESULTS

Equisetum giganteum L and Copaifera reticulate Ducke efficiently blocked HSV-2 infection of cell cultures without major cell cytotoxic effects. Extracts of Equisetum giganteum L and Copaifera reticulate Ducke could prevent HSV-2 disease development when administered together with virus in a mouse model of genital HSV-2 infection. In vitro analyses revealed that both plant extracts exerted their anti-HSV-2 effects by interfering with viral cell attachment and entry, but could not block viral replication post entry.

CONCLUSIONS

These studies show that extracts of Equisetum giganteum L and Copaifera reticulate Ducke have potent antiviral activities against HSV-2 comparable to those two previously identified plants, Croton lechleri Müll. Arg. and Uncaria tomentosa (Willd. ex Schult.) DC. These studies confirm that plants used by the Tacana tribe could be explored further for the development of novel topical antiviral microbicides.

A Perspective on the Phytopharmaceuticals Responsible for the Therapeutic Applications

The word phytopharmaceutical deals with a complex mixture of compounds derived from the plant source that is used as a medicine or drug. Primitive human societies have been depending on plants and plant products for various remedies. Several plants in the different forms have been reported in traditional medicine and to find a rational for the treatment of various diseases than to isolated single compounds. Many of the single compounds isolated from the plant origin are effectively used in the medicine. The search of natural products in drug discovery has been greatly enhanced in the last few years. The impetus to use phytopharmaceutical agents for the treatment of disease, most of the plant based drugs are quite safe and have lesser adverse effects and are claimed that it works as synergistic effects.

A comparative study on volatile metabolites profile of Dracaena cochinchinensis (Lour.) S.C. Chen xylem with and without resin using GC-MS

Dragon's blood is a famous traditional Chinese medicine produced from source plants under bio- or abio-stress. Dracaena cochinchinensis (Lour.) S.C. Chen xylem (DX) is one of the most important sources of the medicine. In this work, a GC-MS method was developed for analysis of the n-hexane extracts of DX with resin (DXR) and without resin (DXW). The repeatability of the method was also investigated for a metabolite comparative study of the different xylems. About 80 components were detected, 26 of which were identified in both DXR and DXN. Three sesquiterpenes (τ-cadinol, τ-muurolon and α-cadinol) were first discovered in Dracaena cochinchinensis (Lour.) S.C. Chen. The chromatographs of the two plant materials were compared and differences of compounds were found. It showed that phytosterols showed a dramatic rise in content, and sesquiterpenes were found to be synthesized in DXR.

Crofelemer for the treatment of secretory diarrhea

Secretory diarrhea is a leading cause of morbidity and mortality worldwide. Crofelemer is a first-in-class antidiarrheal agent that simultaneously targets two distinct channels, the cystic fibrosis conductance regulator and calcium-activated chloride channel, responsible for chloride and fluid secretion in the GI tract. Crofelemer is a novel compound extracted from the stem bark latex of the Croton lechleri tree found in the western Amazonian region of South America. There is little to no systemic absorption of crofelemer when given orally and studies have shown minimal toxicity beyond mild gastrointestinal effects. In studies in diarrheal illness associated with primarily a secretory component, such as cholera, travelers' diarrhea and acute infectious diarrhea, crofelemer has shown improvements in stool consistency and duration of symptoms. Less clear, but interesting, results have been observed in other diarrheal diseases associated with a mixed pathology, including diarrhea in patients with HIV and diarrhea-predominant irritable bowel syndrome.

Crofelemer, a novel agent for treatment of secretory diarrhea

OBJECTIVE

To review the chemistry, pharmacology, pharmacokinetics, efficacy, and safety of crofelemer.

DATA SOURCES

A literature search using the terms SP-303, Provir, and crofelemer was performed with PubMed (up to April 2010), Google Scholar, and selected Ovid bibliography searches. Additional references from the bibliographies of articles included in the search, as well as company and Food and Drug Administration Web sites, were also assessed.

DATA EXTRACTION

English-language in vitro and clinical studies associated with the safety and efficacy of crofelemer were included.

DATA SYNTHESIS

Crofelemer is a first-in-class agent that may be useful for different types of secretory diarrhea, since it prevents chloride and fluid secretion into the bowel by directly inhibiting 2 distinct intestinal chloride channels. Crofelemer significantly brought about faster symptom resolution in patients with traveler's diarrhea, along with lower rates of treatment failure compared to placebo-treated patients. In a post hoc analysis, crofelemer compared to placebo also appears to have reduced abnormal stool weight and frequency in patients with AIDS-associated diarrhea. In a third trial, crofelemer did not offer a significant benefit in improving stool consistency after 12 weeks of treatment in patients with diarrhea-predominant irritable bowel syndrome. However, a significant increase in pain-free days was noted in female patients. Preliminary studies also show that crofelemer may reduce watery stool output in patients with infectious diarrhea such as cholera. Oral crofelemer seemed to be well tolerated in clinical trials, with adverse effect profiles comparable to those with placebo.

CONCLUSIONS

Crofelemer possesses a novel mechanism of action that shows promise in treating secretory diarrhea of several etiologies. However, results from further Phase 3 clinical trials are still needed in order to fully evaluate the efficacy and safety of this agent.

Proanthocyanidin from blueberry leaves suppresses expression of subgenomic hepatitis C virus RNA

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease such as chronic hepatitis, cirrhosis, and hepatocellular carcinoma. While searching for new natural anti-HCV agents in agricultural products, we found a potent inhibitor of HCV RNA expression in extracts of blueberry leaves when examined in an HCV subgenomic replicon cell culture system. This activity was observed in a methanol extract fraction of blueberry leaves and was purified by repeated fractionations in reversed-phase high-performance liquid chromatography. The final purified fraction showed a 63-fold increase in specific activity compared with the initial methanol extracts and was composed only of carbon, hydrogen, and oxygen. Liquid chromatography/mass-ion trap-time of flight analysis and butanol-HCl hydrolysis analysis of the purified fraction revealed that the blueberry leaf-derived inhibitor was proanthocyanidin. Furthermore, structural analysis using acid thiolysis indicated that the mean degree of polymerization of the purified proanthocyanidin was 7.7, consisting predominantly of epicatechin. Proanthocyanidin with a polymerization degree of 8 to 9 showed the greatest potency at inhibiting the expression of subgenomic HCV RNA. Purified proanthocyanidin showed dose-dependent inhibition of expression of the neomycin-resistant gene and the NS-3 protein gene in the HCV subgenome in replicon cells. While characterizing the mechanism by which proanthocyanidin inhibited HCV subgenome expression, we found that heterogeneous nuclear ribonucleoprotein A2/B1 showed affinity to blueberry leaf-derived proanthocyanidin and was indispensable for HCV subgenome expression in replicon cells. These data suggest that proanthocyanidin isolated from blueberry leaves may have potential usefulness as an anti-HCV compound by inhibiting viral replication.

Focus on antivirally active sulfated polysaccharides: from structure-activity analysis to clinical evaluation

In recent years, many compounds having potent antiviral activity in cell culture have been detected and some of these compounds are currently undergoing either preclinical or clinical evaluation. Among these antiviral substances, naturally occurring sulfated polysaccharides and those from synthetic origin are noteworthy. Recently, several controversies over the molecular structures of sulfated polysaccharides, viral glycoproteins, and cell-surface receptors have been resolved, and many aspects of their antiviral activity have been elucidated. It has become clear that the antiviral properties of sulfated polysaccharides are not only a simple function of their charge density and chain length but also their detailed structural features. The in vivo efficacy of these compounds mostly corresponds to their ability to inhibit the attachment of the virion to the host cell surface although in some cases virucidal activity plays an additional role. This review summarizes experimental evidence indicating that sulfated polysaccharides might become increasingly important in drug development for the prevention of sexually transmitted diseases in the near future.

Dragon's blood: botany, chemistry and therapeutic uses

Dragon's blood is one of the renowned traditional medicines used in different cultures of world. It has got several therapeutic uses: haemostatic, antidiarrhetic, antiulcer, antimicrobial, antiviral, wound healing, antitumor, anti-inflammatory, antioxidant, etc. Besides these medicinal applications, it is used as a coloring material, varnish and also has got applications in folk magic. These red saps and resins are derived from a number of disparate taxa. Despite its wide uses, little research has been done to know about its true source, quality control and clinical applications. In this review, we have tried to overview different sources of Dragon's blood, its source wise chemical constituents and therapeutic uses. As well as, a little attempt has been done to review the techniques used for its quality control and safety.

Agents and strategies in development for improved management of herpes simplex virus infection and disease

The quiet pandemic of herpes simplex virus (HSV) infections has plagued humanity since ancient times, causing mucocutaneous infection such as herpes labialis and herpes genitalis. Disease symptoms often interfere with every-day activities and occasionally HSV infections are the cause of life-threatening or sight-impairing disease, especially in neonates and the immuno-compromised patient population. After infection the virus persists for life in neurons of the host in a latent form, periodically reactivating and often resulting in significant psychosocial distress for the patient. Currently no cure is available. So far, vaccines, ILs, IFNs, therapeutic proteins, antibodies, immunomodulators and small-molecule drugs with specific or non-specific modes of action lacked either efficacy or the required safety profile to replace the nucleosidic drugs acyclovir, valacyclovir, penciclovir and famciclovir as the first choice of treatment. The recently discovered inhibitors of the HSV helicase-primase are the most potent development candidates today. These antiviral agents act by a novel mechanism of action and display low resistance rates in vitro and superior efficacy in animal models. This review summarises the current therapeutic options, discusses the potential of preclinical or investigational drugs and provides an up-to-date interpretation of the challenge to establish novel treatments for herpes simplex disease.

A novel extract SB-300 from the stem bark latex of Croton lechleri inhibits CFTR-mediated chloride secretion in human colonic epithelial cells

An oligomeric proanthocyanidin (SP-303) extracted from the bark latex of the tree Croton lechleri (family Euphorbiaceae) is a potent inhibitor of cholera toxin-induced fluid accumulation and chloride secretion. The manufacturing process for SP-303 was optimized and simplified to produce an increased yield of the herbal extract. The novel extract (named SB-300) contained on average 70.6+/-7.2% SP-303 by weight (mean +/- S.D.; n=56 lots). Here, we describe the effectiveness of SB-300 on cAMP-regulated chloride secretion, which is mediated by the cystic fibrosis transmembrane conductance regulator Cl- channel (CFTR) in human colonic T84 cells. Exposure of the apical surface to SB-300 blocked forskolin-stimulated Cl- secretion by 92.2+/-3.0% with a half-maximal inhibition constant (KB) of 4.8+/-0.8 microM. For SP-303, stimulated Cl- currents were decreased by 98.0+/-7.2 % and KB averaged 4.1+/-1.3 microM. There was no significant difference between the blocking kinetics of SP-303 and SB-300. Forskolin-stimulated whole cell Cl- currents were effectively blocked by extracellular addition of SB-300 (63+/-8.5%; n=3) and to a similar extent by SP-303 (83 +/- 0.6%; n=2; at 50 microM each). Both extracts inhibited a time- and voltage-independent Cl- conductance, which indicated the involvement of CFTR Cl- channels. We conclude that both SP-303 (used in Provir) and SB-300 (used in NSF Normal Stool Formula) are novel natural products that target the CFTR Cl- channel. SB-300 is a low cost herbal extract and may present a complementary and alternative medicine approach for the treatment of fluid loss in watery diarrhea.

Review ofSangre de Drago(Croton lechleri) - A South American Tree Sap in the Treatment of Diarrhea, Inflammation, Insect Bites, Viral Infections, and Wounds: Traditional Uses to Clinical Research

OBJECTIVE

The objective of this review is to provide an overview of the pharmacologic evidence that may or may not support clinical and ethnomedical uses of the sap of sangre de drago (dragon's blood; Croton lechleri Müll. Arg.). Data sources used were BIOSIS, EMBASE, PubMed, TOXLIT, International Pharmaceutical Abstracts, manual searches, papers on file from peer-reviewed journals, textbooks available at Armana Research, Inc., and researchers in the field of South American botanical medicine.

CONCLUSIONS

The results of in vitro and in vivo studies largely support the majority of ethnomedical uses of sangre de drago including the treatment of diarrhea, wounds, tumors, stomach ulcers, herpes infection, the itching, pain and swelling of insect bites, and other conditions. Clinical studies of sangre de drago products have reported positive results in the treatment of traveler's and watery diarrhea and the symptoms of insect bites. Because the sap has shown low toxicity and preparations used in clinical studies were well tolerated, further clinical and pharmacologic studies are anticipated. Acknowledgment of the diversity in the chemical makeup of the sap from one geographic area to another and the recent characterization of alkaloid chemotypes of sangre de drago will require that materials developed for clinical use are standardized.

Antiherpesvirus drugs: a promising spectrum of new drugs and drug targets

In the absence of effective vaccines to control herpesvirus infections, nucleosidic antiviral drugs have been the mainstay of clinical treatment since their development in the late 1970s. However, given the drawbacks of these drugs, including the increasing emergence of drug-resistant clinical isolates, new strategies for treating herpesvirus infections are warranted. A range of promising new drugs with novel molecular targets has been developed, but will they cure latent infections?

Current recommendations for the treatment of genital herpes

The incidence of genital herpes continues to increase in epidemic-like fashion. Aciclovir (acyclovir) has been the original gold standard of therapy. The recent addition of famciclovir and valaciclovir as antiherpes drugs has improved convenience as well as the efficacy of treatment. Although aciclovir remains a widely prescribed and reliable drug, its administration schedule falls short of the ease of usage that the newer nucleoside analogues offer, for both episodic and suppressive therapy. Suppression of symptomatic disease and asymptomatic shedding from the genitalia have both become popular approaches, if not the primary targets of antiviral therapy. Knowing that asymptomatic disease leads to most cases of transmission strongly suggests that suppression with antiviral agents could reduce transmission risk in discordant couples. Unfortunately, the role for antivirals in reducing transmission remains to be proven in clinical trials. Neonatal herpes is now successfully treated using aciclovir. Current randomised clinical trials are examining aciclovir and valaciclovir administration, as well as safety and efficacy for post-acute suppressive therapy. Prevention of recurrences in pregnancy is also a topic under investigation, with a view to reducing the medical need for Cesarean section, or alternatively (and far less likely to be accomplished) to protect the neonate. Although resistance is largely limited to the immunocompromised and a change in resistance patterns is not expected, several drugs are available for the treatment of aciclovir-resistant strains of herpes simplex. Foscarnet is the main alternative with proven efficacy in this setting. Unfortunately, administration of foscarnet requires intravenous therapy, although a single anecdote of topical foscarnet efficacy in this setting has been published. Alternatives include cidofovir gel, which is not commercially available but can be formulated locally from the intravenous preparation. Less effective alternatives include trifluridine and interferon. Future possibilities for treatment of genital herpes include a microparticle-based controlled-release formulation of aciclovir and resiquimod (VML-600; R-848). The search for an effective therapeutic vaccine for genital herpes has not been successful to date, although a live virus glycoprotein H-deficient (DISC) vaccine is currently in clinical trials. Recent data suggest that seronegative women are protected (albeit, not fully) by a glycoprotein D recombinant vaccine with adjuvant. Despite the established safety and convenience of current treatment options, better suppressive options and topical treatment options are much needed. Studies using existing agents as potential tools to avoid Cesarean section, or transmission to neonate or partner are ongoing. Both vaccines and antivirals may eventually play a role in prevention of infection.

Plant products as antimicrobial agents

The use of and search for drugs and dietary supplements derived from plants have accelerated in recent years. Ethnopharmacologists, botanists, microbiologists, and natural-products chemists are combing the Earth for phytochemicals and "leads" which could be developed for treatment of infectious diseases. While 25 to 50% of current pharmaceuticals are derived from plants, none are used as antimicrobials. Traditional healers have long used plants to prevent or cure infectious conditions; Western medicine is trying to duplicate their successes. Plants are rich in a wide variety of secondary metabolites, such as tannins, terpenoids, alkaloids, and flavonoids, which have been found in vitro to have antimicrobial properties. This review attempts to summarize the current status of botanical screening efforts, as well as in vivo studies of their effectiveness and toxicity. The structure and antimicrobial properties of phytochemicals are also addressed. Since many of these compounds are currently available as unregulated botanical preparations and their use by the public is increasing rapidly, clinicians need to consider the consequences of patients self-medicating with these preparations.

Approaches and strategies for the treatment of influenza virus infections

Influenza A and B viruses belong to the Orthomyxoviridae family of viruses. These viruses are responsible for severe morbidity and significant excess mortality each year. Infection with influenza viruses usually leads to respiratory involvement and can result in pneumonia and secondary bacterial infections. Vaccine approaches to the prophylaxis of influenza virus infections have been problematic owing to the ability of these viruses to undergo antigenic shift by exchanging genomic segments or by undergoing antigenic drift, consisting of point mutations in the haemagglutinin (HA) and neuraminidase (NA) genes as a result of an error-prone viral polymerase. Historically, antiviral approaches for the therapy of both influenza A and B viruses have been largely unsuccessful until the elucidation of the X-ray crystallographic structure of the viral NA, which has permitted structure-based drug design of inhibitors of this enzyme. In addition, recent advances in the elucidation of the structure and complex function of influenza HA have resulted in the discovery of a number of diverse compounds that target this viral protein. This review article will focus largely on newer antiviral agents including those that inhibit the influenza virus NA and HA. Other novel approaches that have entered clinical trials or been considered for their clinical utility will be mentioned.