Suppression of recurrent genital herpes simplex virus type 2 infection by Rhus javanica in guinea pigs

A comprehensive review on ethnobotanical, phytochemical and pharmacological aspects of Rhus chinensis Mill

ETHNOPHARMACOLOGICAL RELEVANCE

Rhus chinensis Mill., firstly recorded as herbal medicine in Shan Hai Jing, have been used for thousands of years to treat various diseases.

AIM OF THIS REVIEW

This review targets on the ethnomedicinal applications of R. chinensis and to gather the phytochemical, pharmacological and toxicological data which support the therapeutic potential of R. chinensis in treatment on different diseases, with emphasis on the naturally occurring compounds and detailed pharmacological developments.

MATERIALS AND METHODS

The information of R. chinensis was collected based on a variety of popular databases such as Scifinder, PubMed, Web of Science, ScienceDirect, Springer, Wiley, ACS, CNKI, Baidu Scholar, Google Scholar and other published materials (books and Ph.D. and M. Sc. Dissertations). The keywords "Rhus chinensis", "Rhus amela", "Rhus javanica", "Rhus osbeckii", "Rhus semialata", and "Schinus indicus" were applied to search the literature related in this review.

RESULTS

152 natural compounds of R. chinensis belong to different classes are presented in this review, including flavonoids, lignans, coumarins, simple phenolics, urushiols, tannins, triterpenoids, steroids and other types of constituents. Among them, flavonoids, lignans, and triterpenoids are most frequently reported components. The pharmacological effects of R. chinensis were numerous and complicated, including anti-viral, anti-bacterial, anti-diarrheal, hepatoprotective, anti-proliferation, enzyme-inhibiting, anti-oxidants and so on.

CONCLUSION

In order to discover more compounds with novel structures to both enrich chemical context of genus Rhus and expand the variety of constituents, the phytochemical research is urgent and indispensable. Anti-diarrhea, the most widely application of R. chinensis traditionally, is insufficient in underlying mechanism exploration. And for other activities, in-depth studies on the mechanism of pharmacological effects in vivo and in vitro are both needed. Meanwhile, pharmacokinetics, toxicology, quality control and preclinical and clinical data are urgent to assess the rationale and safety of the medicinal and food application of R. chinensis.

Phytochemicals of Rhus spp. as Potential Inhibitors of the SARS-CoV-2 Main Protease: Molecular Docking and Drug-Likeness Study

Background

The outbreak of coronavirus disease 2019 (COVID-19) induced by the novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) originated in China and spread to cover the entire world with an ongoing pandemic. The magnitude of the situation and the fast spread of the new and deadly virus, as well as the lack of specific treatment, led to a focus on research to discover new therapeutic agents.

Aim

In this study, we explore the potential inhibitory effects of some active polyphenolic constituents of Rhus spp. (sumac) against the SARS-CoV-2 main protease enzyme (M^pro; 6LU7).

Methods

26 active polyphenolic compounds of Rhus spp. were studied for their antiviral activity by molecular docking, drug likeness, and synthetic accessibility score (SAS) as inhibitors against the SARS-CoV-2 M^pro.

Results

The results show that all tested compounds of sumac provided good interaction with the main active site of SARS-CoV-2 M^pro, with better, lower molecular docking energy (kcal/mol) compared to the well-known drugs chloroquine and favipiravir (Avigan). Only six active polyphenolic compounds of Rhus spp. (sumac), methyl 3,4,5-trihydroxybenzoate, (Z)-1-(2,4-dihydroxyphenyl)-3-(3,4-dihydroxyphenyl)-2-hydroxyprop-2-en-1-one, (Z)-2-(3,4-dihydroxybenzylidene)-6-hydroxybenzofuran-3(2H)-one, 3,5,7-trihydroxy-2-(4-hydroxyphenyl)chroman-4-one, 2-(3,4-dihydroxyphenyl)-3,5-dihydroxy-7-methoxy-4H-chroman-4-one, and 3,7-dihydroxy-2-(4-hydroxyphenyl)chroman-4-one, were proposed by drug likeness, solubility in water, and SAS analysis as potential inhibitors of M^pro that may be used for the treatment of COVID-19.

Conclusion

Six phenolic compounds of Rhus spp. are proposed for synthesis as potential inhibitors against M^pro and have potential for the treatment of COVID-19. These results encourage further in vitro and in vivo investigations of the proposed ligands and research on the preventive use of Rhus spp. against SARS-CoV-2.

Review of Whole Plant Extracts With Activity Against Herpes Simplex Viruses In Vitro and In Vivo

Herpes simplex viruses, HSV-1 and HSV-2, are highly contagious and cause lifelong, latent infections with recurrent outbreaks of oral and/or genital lesions. No cure exists for HSV-1 or HSV-2 infections, but antiviral medications are commonly used to prevent and treat outbreaks. Resistance to antivirals has begun to emerge, placing an importance on finding new and effective therapies for prophylaxis and treatment of HSV outbreaks. Botanicals may be effective HSV therapies as the constituents they contain act through a variety of mechanisms, potentially making the development of antiviral resistance more challenging. A wide variety of plants from different regions in the world have been studied for antiviral activity against HSV-1 and/or HSV-2 and showed efficacy of varying degrees. The purpose of this review is to summarize research conducted on whole plant extracts against HSV-1 and/or HSV-2 in vitro and in vivo. The majority of the research reviewed was conducted in vitro using animal cell lines, and some studies used an animal model design. Also summarized are a limited number of human trials conducted using botanical therapies on HSV lesions.

Recent progress in the antiviral activity and mechanism study of pentacyclic triterpenoids and their derivatives

Viral infections cause many serious human diseases with high mortality rates. New drug‐resistant strains are continually emerging due to the high viral mutation rate, which makes it necessary to develop new antiviral agents. Compounds of plant origin are particularly interesting. The pentacyclic triterpenoids (PTs) are a diverse class of natural products from plants composed of three terpene units. They exhibit antitumor, anti‐inflammatory, and antiviral activities. Oleanolic, betulinic, and ursolic acids are representative PTs widely present in nature with a broad antiviral spectrum. This review focuses on the recent literatures in the antiviral efficacy of this class of phytochemicals and their derivatives. In addition, their modes of action are also summarized.

Potential Wound Healing Activities of Galla Rhois in Human Fibroblasts and Keratinocytes

Wound healing is a complex process orchestrated by the regeneration of the epithelium and the remodeling of the extracellular matrix through processes like collagen deposition. Galla Rhois has been widely used in traditional Korean medicine for its various pharmacological effects, including an anticoccidial effect, however, little is known about its healing activity. The purpose of this study was to determine the effects of Galla Rhois ethanol extract (GRE) on wound healing activities, including H2O2-induced oxidative stress, cell migration, and lactate dehydrogenase (LDH) release assays using human keratinocyte (HaCaT) and dermal fibroblasts (CCD-986SK). In addition, total soluble collagen deposition and collagen gene expression for Type I and III collagen were evaluated in CCD-986SK. Total tannin and flavonoid contents for GRE were measured. GRE induced a significant increase in the number and migration of cells, along with a decrease in cell death and LDH release. In addition, it also induced the over-expression of collagen Type I and III mRNA and caused increased synthesis of total soluble collagen. The contents of total tannin and flavonoid for GRE were 55.7% ([Formula: see text][Formula: see text]mg/g) and 62.9% ([Formula: see text][Formula: see text]mg/g), respectively. The results suggest that GRE can cause accelerated wound healing by increasing cell survival, proliferation, migration, and collagen synthesis along with a potential anti-oxidant property. This evidence provides novel insight into natural therapy for tissue injury.

Bioactive natural products with anti-herpes simplex virus properties

Objectives

In this review, we highlight and summarise the most promising extracts, fractions and pure compounds as potential anti-herpes simplex virus (HSV) agents derived from microorganisms, marine organisms, fungi, animals and plants. The role of natural products in the development of anti-HSV drugs will be discussed.

Key findings

Herpes simplex viruses (HSV-1 and -2) are common human pathogens that remain a serious threat to human health. In recent years, a great interest has been devoted to the search for integrated management of HSV infections. Acyclovir and related nucleoside analogues have been licensed for the therapy that target viral DNA polymerase. Although these drugs are currently effective against HSV infections, the intensive use of these drugs has led to the problem of drug-resistant strains. Therefore, the search for new sources to develop new antiherpetic agents has gained major priority to overcome the problem.

Summary

Natural products as potential, new anti-HSV drugs provide several advantages such as reduced side effects, less resistance, low toxicity and various mechanisms of action. This paper aims to provide an overview of natural products that possess antiviral activity against HSV.

Penta-O-galloyl-β-D-glucose ameliorates inflammation by inhibiting MyD88/NF-κB and MyD88/MAPK signalling pathways

BACKGROUND AND PURPOSE

The gallnut of Rhus chinensis MILL and its main constituent penta-O-galloyl-β-D-glucose (PGG) inhibited NF-κB activation in LPS-stimulated peritoneal and colonic macrophages. Here we have investigated PGG mechanisms underlying anti-inflammatory effects of PGG in vitro and in vivo.

EXPERIMENTAL APPROACH

Male C57BL/6 mice (18-22 g, 6 weeks old) were used to prepare peritoneal and colonic macrophages and for the induction of colitis by intrarectal administration of 2,3,4-trinitrobenzene sulphonic acid (TNBS). A range of inflammatory markers and transcription factors were evaluated by elisa, immunoblotting, flow cytometry and confocal microscopy.

KEY RESULTS

Expression of Toll-like receptor (TLR)-4 or Lipopolysaccharide (LPS) binding to TLR-4 in LPS-stimulated peritoneal macrophages was not affected by PGG. However PGG inhibited binding of an anti-MyD88 antibody to peritoneal macrophages, but did not reduce binding of anti-IL-1 receptor-associated kinase (IRAK1) and IRAK4 antibodies to the macrophages with or without transfection with MyD88 siRNA. PGG potently reduced the activation of IRAK1, NF-κB, and MAPKs in LPS- or pepetidoglycan-stimulated peritoneal and colonic macrophages. PGG suppressed IL-1β, TNF-α and IL-6 in LPS-stimulated peritoneal macrophages, while increasing expression of the anti-inflammatorycytokine IL-10. Oral administration of PGG inhibited colon shortening and myeloperoxidase activity in mice with TNBS-induced colitis, along with reducing NF-κB activation and IL-1β, TNF-α, and IL-6 levels, whereas it increased IL-10.

CONCLUSIONS AND IMPLICATIONS

PGG reduced activation of NF-κB and MAPK signalling pathways by directly interacting with the MyD88 adaptor protein. PGG may ameliorate inflammatory diseases such as colitis.

Protective effects of Galla Rhois, the excrescence produced by the sumac aphid, Schlechtendalia chinensis, on transient focal cerebral ischemia in the rat

Galla Rhois is formed by aphids, primarily Schlechtendalia chinensis Bell (Homoptera: Pemphigidae), on the leaf of sumac, Rhus javanica L. (Sapindales: Anacardiaceae). It is a tannin-rich herb that is widely used in traditional Korean medicine. Its various pharmacological effects, including its radical-scavenging effects, have been reported. The purpose of the current study was to determine if these radical-scavenging effects can be confirmed using in vitro assays and to investigate its neuroprotective effects, optimal dosage, mechanisms, and therapeutic time window in an animal model of stroke. Galla Rhois 85% methanol extract (GRE) exhibited potent and dose-dependent radical-scavenging effects on various radicals. Oral administration of GRE (300 mg/kg) in a transient focal cerebral ischemia rat model (two hours of occlusion followed by 22 hours of reperfusion) reduced the brain infarct volume by 37.5%. It also improved sensory motor function and reduced lipid-peroxidation in middle cerebral artery occlusion. However, it did not have any inhibitory effects on brain edema. The time window study revealed that pre- and co-treatment with GRE had protective effects, but post-treatment with GRE (three or six hours after ischemia) did not have protective effects. In conclusion, GRE had potent radical-scavenging activities and neuroprotective effects in a rat model of stroke when it was pre- and co-administered. The optimal dosage may be around 300 mg/kg for oral administration.

Rhus chinensis and Galla Chinensis--folklore to modern evidence: review

The species Rhus chinensis Mill. (Anacardiaceae) is an important representative of the genus Rhus, which contains over 250 individual species found in temperate and tropical regions worldwide. Rhus chinensis has long been used by folk medicine practitioners in Asia. Leaves, roots, stem, bark, fruit and particularly the galls on Rhus chinensis leaves, Galla chinensis, are recognized to have preventative and therapeutic effects on different ailments (such as diarrhea, dysentery, rectal and intestinal cancer, diabetes mellitus, sepsis, oral diseases and inflammation). However, it is critical to separate evidence from anecdote. Fortunately, recent scientific research has revealed that Rhus chinensis compounds possess strong antiviral, antibacterial, anticancer, hepatoprotective, antidiarrheal and antioxidant activities. Moreover, compounds isolated from the stem of Rhus chinensis significantly suppressed HIV-1 activity in vitro. Compounds from this plant were also found to inhibit enamel demineralization in vitro and enhance remineralization of dental enamel with fluoride. This review highlights claims from traditional and tribal medicinal lore and makes a contemporary summary of phytochemical, biological and pharmacological findings on this plant material. It aims to show that the pharmaceutical potential of this plant deserves closer attention.

Ethnomedicines and ethnomedicinal phytophores against herpesviruses

Herpesviruses are important human pathogens that can cause mild to severe lifelong infections with high morbidity in susceptible adults. Moreover, Herpes simplex virus (HSV) type 2, for example, has been reported to be responsible for increased transmission and disease progression of human immunodeficiency virus (HIV). Therefore, the discovery of novel anti-HSV drugs deserves great efforts. Herbal medicinal products have been used as source of putative candidate drugs in many diseases. However, in case of viral diseases the development of antivirals from natural source is less explored probably because within the virus there are few specific targets where the small molecules can interact to inhibit or kill the virus. The currently available antiherpes drugs are nucleoside analogs that did not cure the lifelong or recurrent infections and the use of these drugs often lead to the development of viral resistance coupled with the problem of side effects, recurrence and viral latency. However a wide array of herbal products, used by diverse medicinal systems throughout the world, showed high level of antiherpesvirus activities and many of them have complementary and overlapping mechanism of action, either by inhibiting viral replication, or viral genome synthesis. This chapter will summarize some of the promising herbal extracts and purified compounds isolated from the herbal sources by several laboratories. Cases with proven in vitro and documented in vivo activities, along with their structure-activity relationship against herpesviruses are discussed.

Growth of herpes simplex virus in epidermal keratinocytes determines cutaneous pathogenicity in mice

Herpes simplex viruses (HSV)-1 and -2 isolated from genital lesions were examined for cutaneous pathogenicity and its correlation with cellular tropism. HSV-1 caused vesiculation, erosion/ulcer, and zosteriform lesions successively, but skin lesions of HSV-2 developed without vesiculation in some mice, and with statistically significantly less frequent vesiculation than HSV-1. Thus, the virological type of HSV was correlated with its cutaneous pathogenicity. The growth characteristics of HSV-1 and -2 were compared in cultured human embryonic lung (HEL) fibroblasts, human lung cancer A549 cells, human neonatal epidermal keratinocytes, human neonatal dermal fibroblasts, HeLa cells, and Vero cells. HSV-2 produced plaques that were 72% times the size of HSV-1 plaques in epidermal keratinocytes but 230%-500% the size in the other cells. The difference between HSV-1 and -2 in the ratio of plaque size to virus yield in epidermal keratinocytes was much larger (502 times) than the ratio of the other cells (5.57-28.8 times). Keratinocytes are the major constituent of the epidermal layer of the skin and the cells in which vesiculation and erosion/ulceration occur histologically. Therefore, the smaller spread of HSV-2 in keratinocytes of the epidermal layer and the greater spread in other cells of the dermal layer might reflect its lesser invasiveness in the epidermal layer despite larger invasiveness in the dermal layer, which is reflected in the low incidence of erosion/ulcer of the skin compared to HSV-1. Thus, the growth of HSV in epidermal keratinocytes appeared to correlate with the cutaneous pathogenicity causing vesiculation in the skin.

Antidiarrhoeal activity of Rhus javanica ripen fruit extract in albino mice

The antidiarrhoeal effects of the methanolic extract of Rhus javanica ripen fruits (MERJ) were investigated by employing four experimental models of diarrhoea in Swiss albino mice. MERJ treated mice, showed significant reduction in the faecal output and protected them from castor oil-induced diarrhoea. The extract also reduced the intestinal fluid secretion induced by MgSO4 and gastrointestinal motility after charcoal meal administration in the albino mice. No mortality and visible signs of general weakness was observed in the mice following the test extract administration up to 2000 mg/kg dose.

Antiviral Agents from Plants and Herbs: A Systematic Review

Background and aims

Many antiviral compounds presently in clinical use have a narrow spectrum of activity, limited therapeutic usefulness and variable toxicity. There is also an emerging problem of resistant viral strains. This study was undertaken to examine the published literature on herbs and plants with antiviral activity, their laboratory evaluation in vitro and in vivo, and evidence of human clinical efficacy.

Methods

Independent literature searches were performed on MEDLINE, EMBASE, CISCOM, AMED and Cochrane Library for information on plants and herbs with antiviral activity. There was no restriction on the language of publication. Data from clinical trials of single herb preparations used to treat uncomplicated viral infections were extracted in a standardized, predefined manner.

Results

Many hundreds of herbal preparations with antiviral activity were identified and the results of one search presented as an example. Yet extracts from only 11 species met the inclusion criteria of this review and have been tested in clinical trials. They have been used in a total of 33 randomized, and a further eight non-randomized, clinical trials. Fourteen of these trials described the use of Phyllanthus spp. for treatment of hepatitis B, seven reporting positive and seven reporting negative results. The other 10 herbal medicines had each been tested in between one and nine clinical trials. Only four of these 26 trials reported no benefit from the herbal product.

Conclusions

Though most of the clinical trials located reported some benefits from use of antiviral herbal medicines, negative trials may not be published at all. There remains a need for larger, stringently designed, randomized clinical trials to provide conclusive evidence of their efficacy.

Herbal medicines for sexually transmitted diseases and AIDS

Sexually transmitted diseases (STDs) and acquired immunodeficiency syndrome (AIDS) are gaining significant importance at present due to rapid spread of the diseases, high cost of treatment, and the increased risk of transmission of other STDs and AIDS. Current therapies available for symptomatic treatment of STDs and AIDS are quite expensive beyond the reach of common man and are associated with emergence of drug resistance. Many patients of STDs and AIDS are seeking help from alternative systems of medicines such as Unani, Chinese, Ayurvedic, naturopathy, and homeopathy. Since a long time, medicinal plants have been used for the treatment of many infectious diseases without any scientific evidence. At present there is more emphasis on determining the scientific evidence and rationalization of the use of these preparations. Research is in progress to identify plants and their active principles possessing activity against sexually transmitted pathogens including human immunodeficiency virus (HIV) with an objective of providing an effective approach for prevention of transmission and treatment of these diseases. In the present review, plants reported to possess activity or used in traditional systems of medicine for prevention and treatment of STDs including AIDS, herbal formulations for vaginal application, and topical microbicides from herbal origin, have been discussed.