Screening of anti-dengue activity in methanolic extracts of medicinal plants

Andrographolide, diterpenoid constituent of Andrographis paniculata: Review on botany, phytochemistry, molecular docking analysis, and pharmacology

Andrographispaniculata (kalmegh) is also known as "king of bitters", is an herbaceous plant belongs to family Acanthaceae. The therapeutic effect is due to presence of diterpenoid lactone derivatives of A. paniculata mainly andrographolide. The main purpose of this review includes detailed (past and present) study of A. paniculata and its most important component andrographolide a diterpenoid lactone with respect to its botany, phytochemistry, molecular docking analysis and pharmacological effects i.e., therapeutic benefits. In reference to the search, we also compiled variety of dosage forms available, which are made up of A. paniculata extract and Andrographolide such as tablets and capsules. This review also discusses reported methods of extraction of phytoconstituents, pharmacokinetics of main components, their molecular docking analysis data and main therapeutic applications with their proposed mechanism of actions in various diseases. According to data collected, A. paniculata is becoming more and more valuable as a therapeutic herb.

Dengue havoc: overview and eco-friendly strategies to forestall the current epidemic

Dengue fever is a mosquito-borne viral illness that affects over 100 nations around the world, including Africa, America, the Eastern Mediterranean, Southeast Asia, and the Western Pacific. Those who get infected by virus for the second time are at greater risk of having persistent dengue symptoms. Dengue fever has yet to be treated with a long-lasting vaccination or medication. Because of their ease of use, mosquito repellents have become popular as a dengue prevention technique. However, this has resulted in environmental degradation and harm, as well as bioaccumulation and biomagnification of hazardous residues in the ecosystem. Synthetic pesticides have caused a plethora of serious problems that were not foreseen when they were originally introduced. The harm caused by the allopathic medications/synthetic pesticides/chemical mosquito repellents has paved the door to employment of eco-friendly/green approaches in order to reduce dengue cases while protecting the integrity of the nearby environment too. Since the cases of dengue have become rampant these days, hence, starting the medication obtained from green approaches as soon as the disease is detected is advisable. In the present paper, we recommend environmentally friendly dengue management strategies, which, when combined with a reasonable number of vector control approaches, may help to avoid the dengue havoc as well as help in maintaining the integrity of the ecosystem.

Eugenol isolated from supercritical fluid extract of Ocimum sanctum: a potent inhibitor of DENV-2

Dengue is one of the fairly prevalent viral infections at the world level transmitted through mosquitoes (Aedes aegypti and Aedes albopictus). Due to various environmental factors, dengue cases surged rapidly at the global level in recent decades, with 193245 cases in 2021 and an increment of 110473 cases in 2022. There is no antidote available against dengue and other flaviviruses. In the absence of a dengue vaccine or specific antiviral, medicinal plants or their products can be the only choice for its effective management. Ocimum sanctum is known as ''The Incomparable One,'' ''Mother Medicine of Nature'' and ''Queen of Herbs'' in Ayurveda, and is considered an "elixir of life" supreme in both healthcare and spiritual terms. In present study eugenol was isolated in O.sanctum. Eugenol (1-hydroxy-2-methoxy-4-allylbenzene) has been substantially responsible for its therapeutic potential. High-performance thin-layer chromatography, Fourier transform infrared spectroscopy and ultraviolet-visible spectroscopy were applied to identify the compound. The Rf value of isolated compound was same in the chromatogram (0.69 + 0.05) with compare to standard. The safe dose of plant and eugenol were found as < 31.25 μg/ml and < 15.62 µg/ml. The anti-dengue activity was assessed in C6/36 cell lines, their effect was determined through Quantitative PCR. The NMR of the isolated eugenol showed similar properties as the commercial marker compound. The eugenol and SFE extract of O. sanctum showed the inhibition of 99.28% and completely against Dengue-2, respectively. Docking study exposed that the interaction of eugenol with NS1 and NS5 dengue protein showed the binding energy as - 5.33 and - 5.75 kcal/mol, respectively. The eugenol from the O. sanctum plant has the potential to be a good source of future treatment medications for dengue illness, as well as a valuable tool in its successful management.

Public Health and the Politics of Knowledge: The Role of Traditional Medicine in the Management of COVID-19 in Two South Indian States

Public health discourse about COVID-19 pandemic has mostly been framed around biomedical interventions, although there is evidence of the effective use of traditional medicine (TM) to manage the pandemic by some Asian countries such as China, Thailand, Vietnam and India. This article aims to place on record the policy of medical pluralism in the two South Indian states of Tamil Nadu and Kerala in their respective deployment of Siddha and Ayurveda in the management of COVID-19. Based on interviews with physicians of TM and health administrators, press reports, social media posts and published research, this article reconstructs the crucial yet undocumented process of incorporating TM in the biomedicine-based health bureaucracy in Tamil Nadu and Kerala to deal with infectious fevers such as dengue and chikungunya in the past and COVID-19 in the present. It is our argument that those methods of TM which are safe and in long recent use could provide low-cost and accessible means of prevention and early treatment of infectious fevers. They have to be identified and subjected to further investigation as innovations in social medicine brought forth by the state and its officials and are different from the highly expensive projects of the corporate pharmaceutical sector.

Identification, Validation and Standardization of Bioactive Molecules Using UPLC/MS-QToF, UHPLC and HPTLC in Divya-Denguenil-Vati: A Penta-Herbal Formulation for Dengue Fever

For the last fifty years, Dengue has been one of the most common mosquito-borne arboviral infections which has spread over the tropical and subtropical world. Divya-Denguenil-Vati (DNV) has been formulated by blending five specific herbs for effective resolution of Dengue fever. In the present study, we aimed to identify, develop, validate, and standardize methods for Divya-Denguenil-Vati (DNV), on UHPLC and HPTLC analytical platforms, with rapid, sensitive, accurate and rugged attributes. At first, 97 phyto-constituents were identified by UPLC/MS-QToF in Divya-Denguenil-Vati. UHPLC method was then developed and validated for simultaneous determination of gallic acid, 5-HMF, protocatechuic acid, magnoflorine, methyl gallate, berberine, rutin, ellagic acid, β-ecdysone and rosmarinic acid in DNV. Four selected markers, gallic acid, rosmarinic acid, magnoflorine and rutin were further developed and validated on HPTLC. Analytical processes were validated as per ICH Q2 (R1) guidelines; and were found linear (r² > 0.99), sensitive, precise (%RSD < 5%), and accurate, as indicated by high recovery values (88–105%). The limit of detection and quantification were also established for these phyto-metabolites, with their respective RSDs within 5% limits. Finally, these validated methods were employed to test twenty six different commercial batches of DNV. The quality, reproducibility and consistency of DNV have been well established using these developed and reliable analytical tools. These analytical strategies successfully set a path forward for robust quality evaluation and standardization of Divya-Denguenil-Vati, and other related herbal formulations.

Therapeutic Potential of Medicinal Plants against Dengue Infection: A Mechanistic Viewpoint

Dengue is a tropical disease caused by the Dengue virus (DENV), a positive-sense, single stranded RNA virus of the family Flaviviridae, which is transmitted by Aedes mosquitoes. The occurrence of dengue has grown dramatically around the globe in recent decades, and it is rapidly becoming a global burden. Furthermore, all four DENV serotypes cocirculate and create a problematic hyperendemic situation. Characteristic symptoms range from being asymptomatic, dengue fever to life-threatening complications such as hemorrhagic fever and shock. Apart from the inherent virulence of the virus strain, a dysregulated host immune response makes the condition worse. Currently, there is no highly recommended vaccine or therapeutic agent against dengue. With the advent of virus strains resistant to antiviral agents, there is a constant need for new therapies to be developed. Since time immemorial, human civilization has utilized plants in traditional medicine to treat various diseases, including infectious viral diseases. With the advancement in molecular biology, cell biology techniques, and bioinformatics, recent studies have tried to provide scientific evidence and determine the mechanism of anti-dengue activity of various plant extracts and plant-derived agents. The current Review consolidates the studies on the last 20 years of in vitro and in vivo experiments on the ethnomedicinal plants used against the dengue virus. Several active phytoconstituents like quercetin, castanospermine, α-mangostin, schisandrin-A, hirsutin have been found to be promising to inhibition of all the four DENV serotypes. However, novel therapeutics need to be reassessed in relevant cells using high-throughput techniques. Further, in vivo dose optimization for the immunomodulatory and antiviral activity should be examined on a vast sample size. Such a Review should help take the knowledge forward, validate it, and use medicinal plants in different combinations targeting multiple stages of virus infection for more effective multipronged therapy against dengue infection.

A Comprehensive Review of Andrographis paniculata (Burm. f.) Nees and Its Constituents as Potential Lead Compounds for COVID-19 Drug Discovery

The COVID-19 pandemic has intensively disrupted global health, economics, and well-being. Andrographis paniculata (Burm. f.) Nees has been used as a complementary treatment for COVID-19 in several Asian countries. This review aimed to summarize the information available regarding A. paniculata and its constituents, to provide critical points relating to its pharmacological properties, safety, and efficacy, revealing its potential to serve as a source of lead compounds for COVID-19 drug discovery. A. paniculata and its active compounds possess favorable antiviral, anti-inflammatory, immunomodulatory, and antipyretic activities that could be beneficial for COVID-19 treatment. Interestingly, recent in silico and in vitro studies have revealed that the active ingredients in A. paniculata showed promising activities against 3CLpro and its virus-specific target protein, human hACE2 protein; they also inhibit infectious virion production. Moreover, existing publications regarding randomized controlled trials demonstrated that the use of A. paniculata alone or in combination was superior to the placebo in reducing the severity of upper respiratory tract infection (URTI) manifestations, especially as part of early treatment, without serious side effects. Taken together, its chemical and biological properties, especially its antiviral activities against SARS-CoV-2, clinical trials on URTI, and the safety of A. paniculata, as discussed in this review, support the argument that A. paniculata is a promising natural source for drug discovery regarding COVID-19 post-infectious treatment, rather than prophylaxis.

In Silico Elucidation of Potent Inhibitors from Natural Products for Nonstructural Proteins of Dengue Virus

Medicinal plants have been used from the beginning of human civilization against various health complications. Dengue virus (DENV) has emerged as one of the most widespread viruses in tropical and subtropical countries. Yet no clinically approved antiviral drug is available to combat DENV infection. Consequently, the search for novel antidengue agents from medicinal plants has assumed more insistence than in previous days. This study has focused on 31 potential antidengue molecules from secondary metabolites to examine their inhibitory activity against DENV nonstructural proteins through molecular docking and pharmacokinetics studies. In this research, the wet lab experiments were tested on a computational platform. Agathisflavone and pectolinarin are the top-scored inhibitors of DENV NS2B/NS3 protease and NS5 polymerase, respectively. Epigallocatechin gallate, Pinostrobin, Panduratin A, and Pectolinarin could be potential lead compounds against NS2B/NS3 protease, while acacetin-7-O-rutinoside against NS5 polymerase. Moreover, agathisflavone (LD50= 1430 mg/kg) and pectolinarin (LD50= 5000 mg/kg) exhibited less toxicity than nelfinavir (LD50= 600 mg/kg) and balapiravir (LD50 = 824 mg/kg), and the reference drugs. Further research on clinical trials is required to analyze the therapeutic efficacy of these metabolites to develop new potential drug candidates against different serotypes of DENV.

Effects of Plant Metabolites on the Growth of COVID-19 (Coronavirus Disease-19) Including Omicron Strain

According to recent reports out of India, a new strain of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) B1.1.529 Omicron virus has emerged. In comparison to the Wuhan (WHU) strain and the delta variant, this variant showed a far stronger effect on the angiotensin converting enzyme2 (ACE2) receptor. There are several medicinal compounds in plant metabolites, and their diverse chemical structures make them ideal for the treatment of serious illnesses. It's possible that some of these could be useful alternative pharmaceuticals, as well as a starting point for the repurposing of existing medications and new chemical discoveries. SARS-CoV-2 infection triggered a worldwide epidemic of the severe acute respiratory syndrome (SARS). There have been trials for different therapies for SARS-CoV-2 and so also there are recent announcements of extensive research into the development of viable medicines for this global health calamity. After a thorough examination of plant-derived treatments for COVID-19, investigators in the current study decided to focus on plant-derived secondary metabolites (PSMs). According to some researchers, new MDR (Multi-Drug Resistant) antibiotics may one day be developed due to the adaptability of secondary metabolites. Identifying plant metabolites that can treat a wide range of viral infections was one of the study's aims. Many natural medications that could be recommended for the treatment of COVID-19 were discovered as a result of this research, including remedies from plant families, viral candidates that are susceptible, antiviral assays, and mechanisms of therapeutic action. The findings of this study will inspire further research and speed up the development of new antiviral plant-based medications.

In Vitro Antiviral Activity of Potential Medicinal Plant Extracts Against Dengue and Chikungunya Viruses

Dengue and chikungunya are two important mosquito-borne infections which are known to occur extensively in tropical and subtropical areas. Presently, there is no treatment for these viral diseases. In vitro antiviral screening of 25 extracts prepared from the plants of Vitex negundo, Plumeria alba, Ancistrocladus heyneanus, Bacopa monnieri, Anacardium occidentale, Cucurbita maxima, Simarouba glauca, and Embelia ribes using different solvents and four purified compounds (anacardic acid, chloroquinone, glaucarubinone, and methyl gallate) were carried out for their anti-dengue virus (DENV) and anti-chikungunya virus (CHIKV) activities. Maximum nontoxic concentrations of the chloroform, methanol, ethyl acetate, petroleum ether, dichloromethane, and hydroalcoholic extracts of eight plants were used. The antiviral activity was assessed by focus-forming unit assay, quantitative real-time RT-PCR, and immunofluorescence assays. Extracts from Plumeria alba, Ancistrocladus heyneanus, Bacopa monnieri, and Cucurbita maxima showed both anti-DENV and CHIKV activity while extract from Vitex negundo showed only anti-DENV activity. Among the purified compounds, anacardic acid, chloroquinone and methyl gallate showed anti-dengue activity while only methyl gallate had anti-chikungunya activity. The present study had identified the plant extracts with anti-dengue and anti-chikungunya activities, and these extracts can be further characterized for finding effective phytopharmaceutical drugs against dengue and chikungunya.

Antiviral Potential of Selected Medicinal Herbs and Their Isolated Natural Products

Viruses are responsible for a variety of human pathogenesis. Owing to the enhancement of the world population, global travel, and rapid urbanization, and infectious outbreaks, a critical threat has been generated to public health, as preventive vaccines and antiviral therapy are not available. Herbal medicines and refined natural products have resources for the development of novel antiviral drugs. These natural agents have shed light on preventive vaccine development and antiviral therapies. This review intends to discuss the antiviral activities of plant extracts and some isolated plant natural products based on mainly preclinical (in vitro and in vivo) studies. Twenty medicinal herbs were selected for the discussion, and those are commonly recognized antiviral medicinal plants in Ayurveda (Zingiber officinale, Caesalpinia bonducella, Allium sativum, Glycyrrhiza glabra, Ferula assafoetida, Gymnema sylvestre, Gossypium herbaceum, Phyllanthus niruri, Trachyspermum ammi, Withania somnifera, Andrographis paniculata, Centella asiatica, Curcuma longa, Woodfordia fruticose, Phyllanthus emblica, Terminalia chebula, Tamarindus indica, Terminalia arjuna, Azadirachta indica, and Ficus religiosa). However, many viruses remain without successful immunization and only a few antiviral drugs have been approved for clinical use. Hence, the development of novel antiviral drugs is much significant and natural products are excellent sources for such drug developments. In this review, we summarize the antiviral actions of selected plant extracts and some isolated natural products of the medicinal herbs.

Production, Transmission, Pathogenesis, and Control of Dengue Virus: A Literature-Based Undivided Perspective

Dengue remains one of the most serious and widespread mosquito-borne viral infections in human beings, with serious health problems or even death. About 50 to 100 million people are newly infected annually, with almost 2.5 billion people living at risk and resulting in 20,000 deaths. Dengue virus infection is especially transmitted through bites of Aedes mosquitos, hugely spread in tropical and subtropical environments, mostly found in urban and semiurban areas. Unfortunately, there is no particular therapeutic approach, but prevention, adequate consciousness, detection at earlier stage of viral infection, and appropriate medical care can lower the fatality rates. This review offers a comprehensive view of production, transmission, pathogenesis, and control measures of the dengue virus and its vectors.

Antiviral Activities of Andrographolide and Its Derivatives: Mechanism of Action and Delivery System

Andrographispaniculata (Burm.f.) Nees has been used as a traditional medicine in Asian countries, especially China, India, Vietnam, Malaysia, and Indonesia. This herbaceous plant extract contains active compounds with multiple biological activities against various diseases, including the flu, colds, fever, diabetes, hypertension, and cancer. Several isolated compounds from A. paniculata, such as andrographolide and its analogs, have attracted much interest for their potential treatment against several virus infections, including SARS-CoV-2. The mechanisms of action in inhibiting viral infections can be categorized into several types, including regulating the viral entry stage, gene replication, and the formation of mature functional proteins. The efficacy of andrographolide as an antiviral candidate was further investigated since the phytoconstituents of A. paniculata exhibit various physicochemical characteristics, including low solubility and low bioavailability. A discussion on the delivery systems of these active compounds could accelerate their development for commercial applications as antiviral drugs. This study critically reviewed the current antiviral development based on andrographolide and its derivative compounds, especially on their mechanism of action as antiviral drugs and drug delivery systems.

Anti-dengue activity of super critical extract and isolated oleanolic acid of Leucas cephalotes using in vitro and in silico approach

Backgrounds

Leucas cephalotes is a common ethnomedicinal plant widely used by traditional healers for the treatment of Malaria and other types of fever. Oleanolic acid and its derivatives have been reported for various types of pharmacological activities, such as anti-inflammatory, antioxidant, anticancer, hepatoprotective, anti-HIV and anti-HCV activity.

Methods

L.cephalotes plant extracts were prepared by supercritical fluid extraction (SFE) method and oleanolic acid was isolated by preparatory thin-layer chromatography. The compound was identified and characterize by using ultraviolet-visible spectroscopy (UV-VIS), Fourier transform infra-Red spectroscopy (FT-IR) and high-performance thin-layer chromatography (HPTLC). The structure of the compound was elucidated by proton nuclear magnetic resonance (¹HNMR) and carbon nuclear magnetic resonance (¹CNMR) and the purity checked by differential scanning calorimetry (DSC). The MTT assay was used to determine the toxicity of plant extract and oleanolic acid using a microplate reader at 595 nm. The anti-dengue activity of plant extract and oleanolic acid was tested in vitro and in silico using real-time RT-PCR.

Results

The optimum yield of the extract was obtained at 40 °C temperature and 15Mpa pressure. The maximum non-toxic dose (MNTD) of plant extract and oleanolic acid were found as 46.87 μg/ml and 93.75 μg/ml, respectively in C6/36 cell lines. UV spectrophotometer curve of the isolated compound was overlapped with standard oleanolic acid at 232 nm. Superimposed FT-IR structure of the isolated compound was indicated the same spectra at 3433, 2939, 2871, 1690, 1500,1463, 1387, 1250, 1209, 1137 and 656 position as per marker compound. HPTLC analysis showed the retention factor of L. cephalotes extract was 0.19 + 0.06 as similar to the standard oleanolic acid chromatogram. The NMR structure of the isolated compound was identified as similar to the marker oleanolic acid structure. DSC analysis revealed the purity of isolated oleanolic acid was 98.27% with a melting point of 311.16 °C. Real-time RT PCR results revealed that L. cephalotes supercritical extract and isolated oleanolic acid showed 100 and 99.17% inhibition against the dengue − 2 virus when treated with MNTD value of plant extract (46.87 μg/ml) and the test compound (93.75 μg/ml), respectively. The molecular study demonstrated the binding energy of oleanolic acid with NS1and NS5 (non-structural protein) were − 9.42 & -8.32Kcal/mol, respectively.

Conclusions

The SFE extract L. cephalotes and its active compound, oleanolic acid inhibiting the activity of dengue-2 serotype in the in vitro and in silico assays. Thus, the L.cephalotes plant could be an excellent source for drug design for the treatment of dengue infection.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03402-2.

Phytoconstituents as Lead Compounds for Anti-Dengue Drug Discovery

Dengue is an arthropod-borne viral disease common in subtropical and tropical regions. The widespread use of traditional medicines in these regions for dengue fever (DF) has encouraged researchers to explore the therapeutic effect of herbs and their phytochemicals in dengue infection. Phytochemicals such as quercetin, baicalein, luteolin, oxindole alkaloids, celastrol and geraniin have shown significant inhibition of dengue virus in vitro. Many phytoconstituents have better selectivity index supporting their safety profile for future development. However, in vivo studies supporting therapeutic potency for these active phytoconstituents are limited. There is a need for studies translating anti-dengue profile of active phytoconstituents to find successful anti-dengue compounds.

Momordica charantia L. Extract Protects Hippocampal Neuronal Cells against PAHs-Induced Neurotoxicity: Possible Active Constituents Include Stigmasterol and Vitamin E

Polycyclic aromatic hydrocarbons (PAHs) have been recognized to cause neurobehavioral dysfunctions and disorder of cognition and behavioral patterns in childhood. Momordica charantia L. (MC) has been widely known for its nutraceutical and health-promoting properties. To date, the effect of MC for the prevention and handling of PAHs-induced neurotoxicity has not been reported. In the current study, the neuroprotective effects of MC and its underlying mechanisms were investigated in mouse hippocampal neuronal cell line (HT22); moreover, in silico analysis was performed with the phytochemicals MC to decipher their potential function as neuroprotectants. MC was demonstrated to possess neuroprotective effect by reducing reactive oxygen species’ (ROS’) production and down-regulating cyclin D1, p53, and p38 mitogen-activated protein kinase (MAPK) protein expressions, resulting in the inhibition of cell apoptosis and the normalization of cell cycle progression. Additionally, 28 phytochemicals of MC and their competence on inhibiting cytochrome P450 (CYP: CYP1A1, CYP1A2, and CYP1B1) functions were resolved. In silico analysis of vitamin E and stigmasterol revealed that their binding to either CYP1A1 or CYP1A2 was more efficient than the binding of each positive control (alizarin or purpurin). Together, MC is potentially an interesting neuroprotectant including vitamin E and stigmasterol as probable active components for the prevention for PAHs-induced neurotoxicity.

Andrographis paniculata (Burm.f.) Nees and its major constituent andrographolide as potential antiviral agents

ETHNOPHARMACOLOGICAL RELEVANCE

Andrographis paniculata (Burm.f.) Nees is widely used all over the world, especially in subtropical regions such as India, Thailand, Vietnam, and China. As a traditional folk Chinese medicine, A. paniculata has been extensively utilized for the treatment of cold, fever, sore throat, cough, carbuncle, and sores, and it is commonly employed for 'clearing heat and resolving toxicity'. Typical symptoms of 'heat and toxicity' include swollen, painful gums, associated with virus-related diseases to a great extent. In vivo and in vitro experiments have demonstrated the potential antiviral properties of A. paniculata and identified its major active constituents against various viruses.

AIM OF THE STUDY

This review focuses on connecting the traditional 'clearing heat and resolving toxicity' effect to compelling recent research advances on the antiviral effects of A. paniculata, explaining its major antiviral mechanisms, and assessing the shortcomings of existing work. Besides, ethnobotany, ethnopharmacological uses, phytochemicals, and toxicology of A. paniculata have been researched.

MATERIALS AND METHODS

The information about A. paniculata was collected from various sources including classic books about Chinese herbal medicine, and scientific databases including WEB OF SCIENCE, PubMed, ScienceDirect, Springer, ACS, SCOPUS, CNKI, CSTJ, and WANFANG.

RESULTS

In this review, the underlying mechanisms of antiviral effect mainly involve the regulation of virus entry, gene replication, and synthesis of functionally mature proteins. Also, A. paniculata is a safe agent without obvious toxicity. Ethnobotany, ethnopharmacological uses, and chemical constituents have been summarized.

CONCLUSION

Andrographis paniculata (Burm.f.) Nees could be used as an imperative complementary medicine for the treatment of diverse virus infection, efforts should be made to gain insights into its antiviral properties.

Andrographis paniculata (Burm. f.) Wall. ex Nees: An Updated Review of Phytochemistry, Antimicrobial Pharmacology, and Clinical Safety and Efficacy

Infectious disease (ID) is one of the top-most serious threats to human health globally, further aggravated by antimicrobial resistance and lack of novel immunization options. Andrographis paniculata (Burm. f.) Wall. ex Nees and its metabolites have been long used to treat IDs. Andrographolide, derived from A. paniculata, can inhibit invasive microbes virulence factors and regulate the host immunity. Controlled clinical trials revealed that A. paniculata treatment is safe and efficacious for acute respiratory tract infections like common cold and sinusitis. Hence, A. paniculata, mainly andrographolide, could be considered as an excellent candidate for antimicrobial drug development. Considering the importance, medicinal values, and significant role as antimicrobial agents, this study critically evaluated the antimicrobial therapeutic potency of A. paniculata and its metabolites, focusing on the mechanism of action in inhibiting invasive microbes and biofilm formation. A critical evaluation of the secondary metabolites with the aim of identifying pure compounds that possess antimicrobial functions has further added significant values to this study. Notwithstanding that A. paniculata is a promising source of antimicrobial agents and safe treatment for IDs, further empirical research is warranted.

Coronavirus Disease 2019 and Herbal Therapy: Pertinent Issues Relating to Toxicity and Standardization of Phytopharmaceuticals

Coronavirus disease 2019 (COVID-19) is a virulent viral disease that has now become a public health emergency of global significance and still without an approved treatment regimen or cure. In the absence of curative drugs and with vaccines development still in progress, alternative approaches to stem the tide of the pandemic are being considered. The potential of a phytotherapeutic approach in the management of the dreaded disease has gained attention, especially in developing countries, with several claims of the development of anti-COVID-19 herbal formulations. This is a plausible approach especially with the increasing acceptance of herbal medicine in both alternative and orthodox medical practices worldwide. Also, the established efficacy of herbal remedies in the treatment of numerous viral diseases including those caused by coronaviruses, as well as diseases with symptoms associated with COVID-19, presents a valid case for serious consideration of herbal medicine in the treatment of COVID-19. However, there are legitimate concerns and daunting challenges with the use of herbs and herbal products. These include issues of quality control, unethical production practice, inadequate information on the composition, use and mechanisms, weak regulatory policies, herb-drug interactions and adverse reactions, and the tendency for abuse. This review discusses the feasibility of intervention with herbal medicine in the COVID-19 pandemic and the need to take proactive measures to protect public health by improving the quality and safety of herbal medicine deployed to combat the disease. Graphical abstract.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43450-021-00132-x.

Synthesis, characterization and evaluation of antidengue activity of enantiomeric Schiff bases derived from S-substituted dithiocarbazate

A series of Schiff bases have been successfully synthesized through the acid-catalyzed condensation of S-substituted dithiocarbazates and three enantiomerically pure monoterpenes, (1 R )-(+)-camphor, (1 S )-(-)-camphor, (1 R )-(-)-camphorquinone, (1 S )-(+)-camphorquinone, ( R )-(-)-carvone and ( S )-(+)-carvone. Spectroscopic results revealed that the Schiff bases containing camphor or carvone likely adopted an E -configuration along the characteristic imine bond while those containing camphorquinone assumed a Z -configuration. The antidengue potential of these compounds was evaluated based on DENV 2 caused cytopathic effect (CPE) reduction-based in vitro evaluation. The compounds were validated through secondary foci forming unit reduction assay (FFURA). Compounds were also tested for their cytotoxicity against Vero cells. The compounds showed variable degrees of antiviral activity with the camphor compounds displaying the highest antidengue potential. The enantiomers of the compounds behaved almost similarly during the antiviral evaluation.

Potential Medicinal Plants for the Treatment of Dengue Fever and Severe Acute Respiratory Syndrome-Coronavirus

While dengue virus (DENV) infection imposes a serious challenge to the survival of humans worldwide, severe acute respiratory syndrome-coronavirus (SARS-CoV) remains the most devastating pandemic in human history. A significant number of studies have shown that plant-derived substances could serve as potential candidates for the development of safe and efficacious remedies for combating these diseases. Different scientific databases were used to source for literature on plants used against these infections. Thirty-five studies described the traditional use of 25 species from 20 families for treating DENV infection with Carica papaya and Euphorbia hirta were the most widely used across different regions. 13 in vivo studies, 32 in vitro studies, and eight clinical studies were conducted on 30 species from 25 families against different DENV serotypes, while plants from 13 families were reported to inhibit different forms of SARS-CoV, all of which were investigated through in vitro studies. Phytoconstituents belonging to various chemical classes were identified to show a wide range of antiviral activity against these infections. Extensive studies on the potentials of medicinal plants are needed to confirm their efficacy. This paper reveals the capabilities of medicinal plants and their phytochemicals in inhibiting DENV and SARS-CoV infections.

In-vitro and in silico activity of Cyamopsis tetragonoloba (Gaur) L. supercritical extract against the dengue-2 virus

Our health and wealth are highly influenced by a number of viruses. Dengue is one of them having a global influence in absence of vaccines and antiviral. WHO suggested that the morbidity of dengue is increasing more than 6 times from 0.5 million in 2010 to over 3.34 million in 2016, following a sharp increase in 2019. The aim of the present study is to check the in vitro and in silico anti-dengue activity of Cyamopsis tetragonoloba supercritical extract in cell lines. The optimum yield of supercritical extract was obtained 0.13 g/10 g (1.3% w/w) at 40 °C temp and 15 MPa pressure and further characterized by GC-MS. The antiviral assay was performed on C6/36 cell lines with 100 copies of dengue-2 virus and maximum non-toxic dose (31.25 µg/ml) of supercritical extract and their effect was detected by real-time RT-PCR. This study revealed that C. tetragonoloba supercritical extract inhibited the dengue-2 virus (99.9%). GC-MS analysis of C. tetragonoloba supercritical extract showed the presence of 10 compounds. The major compounds identified were Hexadecanoic acid, 15-methyl-methyl ester (24.498%); 9,12-octadecadienoyl chloride, (z,z)- (23.718%); methyl dodecanoic acid (13.228%); methyl-stearate (8.696%); Tridecanoic acid, 12-methyl-, methyl-ester (8.426%), dodecanoic acid (6.102%). The study reveals that C. tetragonoloba can be exploited to develop an effective, inexpensive, and specific anti-dengue. The molecular docking study demonstrated the binding energy of 1,2-benzenedicarboxylic acid, bis(2-methylpropyl) ester (- 4.1 kcal/mol), 9,12-octadecadienoyl chloride (z,z) (- 4.0 kcal/mol) ligands were higher than others. It is concluded that C. tetragonoloba can play a major role to inhibit dengue-2 virus.

Andrographolide inhibits IL-1β release in bone marrow-derived macrophages and monocyte infiltration in mouse knee joints induced by monosodium urate

Andrographolide (AND) is the major diterpenoid in A. paniculata with wide clinical application and has been shown to be a potent anti-inflammatory agent. Gout is the leading inflammatory disease of the joints, and the deposition of urate in the articular cavity attracts immune cells that release inflammatory cytokines. Monosodium urate (MSU) is known to be one of the activators of the NLRP3 (NLR family pyrin domain containing 3) inflammasome. After activation, the NLRP3 inflammasome releases interleukin-1β (IL-1β), which causes the development of many inflammatory diseases. The aim of the present study was to investigate whether AND attenuates the release of IL-1β mediated by the NLRP3 inflammasome. The effects of AND were studied in bone marrow-derived macrophages (BMDMs) treated with lipopolysaccharide (LPS) and MSU and in mice with MSU-induced joint inflammation. AND suppressed MSU phagocytosis dose-dependently and markedly inhibited LPS- and MSU-induced IL-1β release in BMDMs. Moreover, AND pretreatment inhibited the LPS-induced NLRP3 inflammasome priming stage by inhibiting the IKK/NFκB signaling pathway, which resulted in decreased protein expression of NLRP3 and proIL-1β. AND induced HO-1 protein expression in a dose-dependent manner and attenuated MSU-induced ROS generation. Silencing HO-1 mitigated AND inhibition of LPS/MSU-induced IL-1β release in J774A.1 cells. In addition, AND decreased MSU-mediated ASC binding to NLRP3. Oral administration of AND attenuated MSU-induced monocyte infiltration in mouse knee joints. These results suggest that the working mechanisms by which AND down-regulates MSU-induced joint inflammation might be via HO-1 induction and attenuation of ROS-mediated NLRP3 inflammasome assembly and subsequent IL-1β release.

A systematic review on phytochemicals for the treatment of dengue

Dengue fever is prevalent in subtopic regions, producing mortality and morbidity worldwide, which have been of major concern to different governments and World Health Organization. The search of new anti-dengue agents from phytochemicals was assumed to be highly emergent in past. The phytochemicals have been used in wide distribution of vector ailments such as malaria. The demand of the phytochemicals is based on the medicines which are mostly considered to be safer, less harmful than synthetic drugs and nontoxic. This review mentions majorly about the phytochemicals potentially inhibiting dengue fever around the world. The phytochemicals have been isolated from different species, have potential for the treatment of dengue. Different crude extracts and essential oils obtained from different species showed a broad activity against different phytochemicals. The current studies showed that natural products represent a rich source of medicines toward the dengue fever. Furthermore, ethnobotanical surveys and laboratory investigation established identified natural plants species in the development of drug discovery to control the dengue fever.

Nexus between light and culture media on morphogenesis in Bacopa monnieri and saponin yield thereof

Bacopa monnieri, a well-documented nootropic plant of high commercial global demand had been explored for its effect in alleviating other diseases and symptoms. This is primarily attributed to different phytocompounds present in the plant. One of the major constituents among them are saponins. However, variation in agro-climatic conditions and choice of germplasm often affect the growth rate and yield of phytocompounds that significantly impact the efficacy of the plant and its extract. Tissue culture has been attempted to improve the yield of phytocompounds but is often restricted by higher cost and scalability. Current study explores the role of commercial hydroponic media ‘Leafy 200’ vis-à-vis Murashige and Skoog (MS) media, under different color and intensity of lights, on plant morphogenesis, biomass and saponin yield. Blue light induced more shoot differentiation than normal white light. Statistical studies performed using fractional factorial design showed no significant variations in the yield of saponins among the extracts. The study suggests that hydroponic culture to be a sustainable solution and possible substitute to tissue culture that may be exploited for scalable cultivation of the plant.

Antiviral and healing potential of Sambucus nigra extracts

Nowadays, the application of alternative methods instead of clinical treatment creates a new possibility to prevent the development of diseases. Medicinal plants such as Sambucus nigra have been well known due to their extraordinary properties. The similarity to synthetic substances makes it potentially dependable; however, a high concentration of cyanogenic glycosides may exert detrimental consequences. It has been documented that Sambucus nigra extracts are used against both human and animal viruses, like influenza A and B viruses, human immunodeficiency virus (HIV), dengue virus (DENV-2), human herpesvirus type 1 (HSV-1) and human coronavirus NL63 (HCoV-NL63). Such reports are notably valuable especially considering the widespread usage of commercial drugs, which could be ineffective. This review provides insight on recent research on the health properties of plant Sambucus nigra as an antiviral medication that may help propose new therapy.

Plants Metabolites: Possibility of Natural Therapeutics Against the COVID-19 Pandemic

COVID-19, a disease induced by SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus-2), has been the cause of a worldwide pandemic. Though extensive research works have been reported in recent days on the development of effective therapeutics against this global health crisis, there is still no approved therapy against SARS-CoV-2. In the present study, plant-synthesized secondary metabolites (PSMs) have been prioritized to make a review focusing on the efficacy of plant-originated therapeutics for the treatment of COVID-19. Plant metabolites are a source of countless medicinal compounds, while the diversity of multidimensional chemical structures has made them superior to treat serious diseases. Some have already been reported as promising alternative medicines and lead compounds for drug repurposing and discovery. The versatility of secondary metabolites may provide novel antibiotics to tackle MDR (Multi-Drug Resistant) microbes too. This review attempted to find out plant metabolites that have the therapeutic potential to treat a wide range of viral pathogens. The study includes the search of remedies belonging to plant families, susceptible viral candidates, antiviral assays, and the mode of therapeutic action; this attempt resulted in the collection of an enormous number of natural therapeutics that might be suggested for the treatment of COVID-19. About 219 plants from 83 families were found to have antiviral activity. Among them, 149 plants from 71 families were screened for the identification of the major plant secondary metabolites (PSMs) that might be effective for this pandemic. Our investigation revealed that the proposed plant metabolites can serve as potential anti- SARS-CoV-2 lead molecules for further optimization and drug development processes to combat COVID-19 and future pandemics caused by viruses. This review will stimulate further analysis by the scientific community and boost antiviral plant-based research followed by novel drug designing.

Validation of a Novel Zebrafish Model of Dengue Virus (DENV-3) Pathology Using the Pentaherbal Medicine Denguenil Vati

Dengue is a devastating viral fever of humans, caused by dengue virus. Using a novel zebrafish model of dengue pathology, we validated the potential anti-dengue therapeutic properties of pentaherbal medicine, Denguenil Vati. At two different time points (at 7 and 14 days post infection with dengue virus), we tested three translational doses (5.8 μg/kg, 28 μg/kg, and 140 μg/kg). Dose- and time-dependent inhibition of the viral copy numbers was identified upon Denguenil Vati treatment. Hepatocyte necrosis, liver inflammation, and red blood cell (RBC) infiltration into the liver were significantly inhibited upon Denguenil treatment. Treatment with Denguenil Vati significantly recovered the virus-induced decreases in total platelet numbers and total RBC count, and concomitantly increasing hematocrit percentage, in a dose- and time-dependent manner. Conversely, virus-induced white blood cell (WBC) counts were significantly normalized. Virus-induced hemorrhage was completely abrogated by Denguenil after 14 days, at all the doses tested. Gene expression analysis identified a significant decrease in disease-induced endothelial apoptotic marker Angiopoetin2 (Ang-2) and pro-inflammatory chemokine marker CCL3 upon Denguenil treatment. Presence of gallic acid, ellagic acid, palmetin, and berberine molecules in the Denguenil formulation was detected by HPLC. Taken together, our results exhibit the potential therapeutic properties of Denguenil Vati in ameliorating pathological features of dengue.

Andrographis Paniculata and Its Bioactive Diterpenoids Protect Dermal Fibroblasts Against Inflammation and Oxidative Stress

Andrographis paniculata (Burm.f.) has long been used in ayurvedic medicine through its anti-inflammatory properties. However, its protective effect of skin aging has not been studied in vitro. This study aimed to investigate the anti-aging effects of methanolic extract (ME), andrographolide (ANDRO), neoandrographolide (NEO), 14-deoxyandrographolide (14DAP) and 14-deoxy-11,12-didehydroandrographolide (14DAP11-12) on human dermal fibroblasts (HDFa) under pro-oxidant or pro-inflammatory condition. The in vitro anti-aging capacity of ME, ANDRO, NEO, 14DAP, and 14DAP11-12 (1, 2.5 and 5 µg/mL) was performed in HDFa. Oxidative stress and inflammation were induced by hydrogen peroxide and lipopolysaccharide/TNF-α, respectively. Reactive oxygen species (ROS) production was measured by the fluorescence of DCF-DA probe and cytokines were quantified by ELISA (IL6 and IL8) or RTqPCR (TNF-α). Procollagen type I production was determined by an ELISA. Our results showed a decrease in ROS production with ME and 14DAP at 5 µg/mL and 1 µg/mL, respectively. Furthermore, IL-6 production and TNF-α expression decreased under ANDRO and ME at 5 µg/mL. Our data indicated that ME and 14DAP protect from oxidative stress. Additionally, ME and ANDRO decreased an inflammation marker, IL-6. This suggests their potential natural treatment against skin damage. Hence, their applications could be of interest in cosmetics for preventing skin ageing.

Antidengue potential of leaf extracts of Pavetta tomentosa and Tarenna asiatica (Rubiaceae) against dengue virus and its vector Aedes aegypti (Diptera: Culicidae)

The aim of the present study was to screen the anti-dengue potential of crude leaf extracts of two plants from Pavetta tomentosa and Tarenna asiatica. For larvicidal assay, the acetone extract of both plants showed maximum effects, with the least LC₅₀ and LC₉₀ values (P. tomentosa (5.968 and 7.493 μg/ml) and T. asiatica (1.288 and 1.992 μg/ml)) and the same extract of both plants exhibited better pupicidal potency. The adulticidal activity of both plants (0-60 min interval periods) recorded best results in acetone extracts and the LC₅₀ and LC₉₀ values were recorded as P. tomentosa (32.105 and 41.001 μg/ml) and T. asiatica (09.012 and 11.854 μg/ml). Among the two plants P. tomentosa acetone leaf extract have good antiviral property against Dengue viral cell line. In addition, the phytochemical nature of the plant reveals the presence of saponins, flavonoids and alkaloids in all the tested extracts of both plants. GC-MS analysis revealed Hexanedioic acid, Bis(2-Ethylhexyl) Ester (22.54) and 2,6,10,14,18,22- Tetracosahexane, 2,6,10, 15, 19,15,19,23- Hexamethyl-(ALL-E)- (25.33) identified as two major phytoconstitutents in P. tomentosa and Tetracontane (23.580) is a major compound identified from T. asiatica acetone extracts. The functional groups of chemical compounds (aromatis, alkanes, alkyls and carboxylic acids) from P. tomentosa and T. asiatica were analyzed by FT-IR spectrum.

In vitro and in silico anti-dengue activity of compounds obtained from Psidium guajava through bioprospecting

BACKGROUND

For decades, bioprospecting has proven to be useful for the identification of compounds with pharmacological potential. Considering the great diversity of Colombian plants and the serious worldwide public health problem of dengue-a disease caused by the dengue virus (DENV)-in the present study, we evaluated the anti-DENV effects of 12 ethanolic extracts derived from plants collected in the Colombian Caribbean coast, and 5 fractions and 5 compounds derived from Psidium guajava.

METHODS

The cytotoxicity and antiviral effect of 12 ethanolic extracts derived from plants collected in the Colombian Caribbean coast was evaluated in epithelial VERO cells. Five fractions were obtained by open column chromatography from the ethanolic extract with the highest selectivity index (SI) (derived from P. guajava, SI: 128.2). From the fraction with the highest selectivity (Pg-YP-I-22C, SI: 35.5), five compounds were identified by one- and two-dimensional nuclear magnetic resonance spectroscopy. The antiviral effect in vitro of the fractions and compounds was evaluated by different experimental strategies (Pre- and post-treatment) using non-toxic concentrations calculated by MTT method. The DENV inhibition was evaluated by plate focus assay. The results were analyzed by means of statistical analysis using Student's t-test. Finally the antiviral effect in Silico was evaluated by molecular docking.

RESULTS

In vitro evaluation of these compounds showed that three of them (gallic acid, quercetin, and catechin) were promising antivirals as they inhibit the production of infectious viral particles via different experimental strategies, with the best antiviral being catechin (100% inhibition with a pre-treatment strategy and 91.8% with a post-treatment strategy). When testing the interactions of these compounds with the viral envelope protein in silico by docking, only naringin and hesperidin had better scores than the theoretical threshold of - 7.0 kcal/mol (- 8.0 kcal/mol and - 8.2 kcal/mol, respectively). All ligands tested except gallic acid showed higher affinity to the NS5 protein than the theoretical threshold.

CONCLUSION

Even though bioprospecting has recently been replaced by more targeted tools for identifying compounds with pharmacological potential, our results show it is still useful for this purpose. Additionally, combining in vitro and in silico evaluations allowed us to identify promising antivirals as well as their possible mechanisms of action.

Potential of medicinal plants to treat dengue

Dengue is a major public health challenge worldwide, particularly in tropical areas. Nearly 390 million infections and 22,000 deaths occur every year. At present, there are no specific therapeutics available to treat dengue; however, possible treatment procedures are explained in the traditional medical systems (TMSs), such as Sri Lankan TMS, Indian Ayurvedic, Unani, and Siddha TMS. In these TMSs, medicinal plants have been used in several ways against dengue, such as virocides, larvicides, and mosquito repellents. Therefore, medicinal plants inherit biologically active compounds/lead compounds that are yet to be identified chemically and physiologically. Herein, we discuss the possible applications of crude plant extracts and isolated phytochemicals from medicinal plants such as quercetin, sulfated galactomannans, flavonoids, and glabranine in controlling dengue. Moreover, medicinal plant-based therapeutics can be safer, cost-effective, and non-toxic. Therefore, this paper reviews the medicinal plants that are used in TMSs to manage dengue, the phytochemicals they contain, and mode of action of these phytochemicals such as virocides, larvicides, and mosquito repellents.

Successful treatment of plantar warts using topical Zijinding, a traditional Chinese medicine preparation: A case series

Introduction

Plantar warts are associated with high transmissibility and morbidity. Among the available therapeutic options, none is uniformly effective or virucidal. Salicylic acid is the first‐line therapy but approximately one‐third of lesions could not resolve and become recalcitrant despite repeated treatment. Cryotherapy is widely accessible with low cost but may be complicated by pain, blister formation, hemorrhage, infection, excessive granulation tissue formation, and hyper‐/hypo‐pigmentation. Hence, alternative treatment modalities are essential.

Methods

Three patients with debilitating plantar warts refractory or intolerant to cryotherapy were treated with a course of Zijinding (a traditional Chinese medicine preparation) paste prepared with white vinegar.

Results

All three patients showed excellent clinical response with Zijinding application with evolution of lesions to scabs and subsequently healthy skin within 1.5 to 5 months of treatment. Treatment was well tolerated and had no significant side effects with excellent compliance recorded for all three patients. There was no relapse for at least 10 months after stopping the treatment.

Conclusion

Topical Zijinding could be a promising alternative modality for the treatment of plantar warts. Further clinical trials on the comparison of Zijinding and other treatment modalities of plantar warts are warranted. Further studies are required to investigate the mechanism of action of Zijinding and to isolate the active ingredient.

Annexin II as a Dengue Virus Serotype 2 Interacting Protein Mediating Virus Interaction on Vero Cells

Recent evidence has demonstrated that dengue virus requires active filopodia formation for a successful infection. However, the cellular factor involved in the interaction has not been fully elucidated. We used a combination of virus overlay protein binding assay and LC-MS/MS, and identified annexin II as a dengue virus serotype 2 (DENV2) interacting protein on Vero cells, upon filopodia induction. Flow cytometry analysis showed annexin II on the Vero cells surface increased when DENV2 was added. The amount of annexin II in the plasma membrane fraction was reduced as the infection progressed. Antibody-mediated inhibition of infection and siRNA-mediated knockdown of annexin II expression significantly reduced DENV2 infection and production levels. Collectively, we demonstrated that annexin II is one of the host factor involved in DENV2 binding on Vero cells.

Structure based virtual screening, 3D-QSAR, molecular dynamics and ADMET studies for selection of natural inhibitors against structural and non-structural targets of Chikungunya

The transmission of mosquito-borne Chikungunya virus (CHIKV) has large epidemics worldwide. Till date, there are neither anti-viral drugs nor vaccines available for the treatment of Chikungunya. Accumulated evidences suggest that some natural compounds i.e., Epigallocatechin gallate, Harringtonine, Apigenin, Chrysin, Silybin, etc. have the capability to inhibit CHIKV replication in vitro. Natural compounds are known to possess less or no side effects. Therefore, natural compound in its purified or crude extracts form could be the preeminent and safe mode of therapies for Chikungunya. Wet lab screening and identification of natural compounds against Chikungunya targets is a time consuming and expensive exercise. In the present study, we used in silico techniques like receptor-ligand docking, Molecular dynamic (MD), Three Dimensional Quantitative Structure Activity Relation (3D-QSAR) and ADME properties to screen out potential compounds. Aim of the study is to identify potential lead/s from natural sources using in silico techniques that can be developed as a drug like molecule against Chikungunya infection and replication. Three softwares were used for molecular docking studies. Potential ligands selected by docking studies were subsequently subjected 3D-QSAR studies to predict biological activity. Based on docking scores and pIC₅₀ value, potential anti-Chikungunya compounds were identified. Best docked receptor-ligands were also subjected to MD for more accurate estimation. Lipinski's rule and ADME studies of the identified compounds were also studied to assess their drug likeness properties. Results of in silico findings, led to identification of few best fit compounds of natural origin against targets of Chikungunya virus which may lead to discovery of new drugs for Chikungunya. Communicated by Ramaswamy H. Sarma.

In vitro large scale production of megakaryocytes to functional platelets from human hematopoietic stem cells

Megakaryocytopoiesis results in the formation of platelets, which are essential for hemostasis. Decreased production or increased destruction of platelets can cause thrombocytopenia, in which platelet transfusion is the mode of treatment. The present study is aimed in generation of megakaryocytes (MKs) and platelet from human hematopoietic stem cells (HSCs). The purity of HSCs was assessed through Flow cytometry and immunocytochemistry (ICC) studies. These pure HSCs were induced with thrombopoietin (TPO), similarly with Andrographis paniculata extract (APE) for 21 days to generate MKs. The APE is mainly composed of andrographolide which stimulates TPO from the liver, and this binds to CD110 present on the surface of HSCs and triggers the proliferation of HSCs and initiate higher MKs population subsequently, a large number of platelets. The results of the present study showed increased proliferation of HSCs grown in the presence of APE and revealed a high population of CD41a and CD42b positive MKs as enumerated by Flow cytometry compared with TPO induced MKs. These results also concurred with qRT-PCR and western blot analysis. The scanning electron microscopy (SEM) revealed the morphology of differentiated MKs and platelets were similar to human blood platelets. The differentiated MKs in APE exhibited polyploidy up to 32 N while TPO induced MKs showed polyploidy of 8 N, these results corroborated with colony forming unit assay. On thrombin stimulation, high expression of P-selectin (CD62p) and fibrinogen binding were detected in APE induced platelets. Autologous transplantation of platelets generated from APE may be a useful option in thrombocytopenia condition.

Microencapsulation and the Characterization of Polyherbal Formulation (PHF) Rich in Natural Polyphenolic Compounds

Microencapsulation of polyherbal formulation (PHF) extract was carried out by freeze drying method, by employing gum arabic (GA), gelatin (GE), and maltodextrin (MD) with their designated different combinations as encapsulating wall materials. Antioxidant components (i.e., total phenolic contents (TPC), total flavonoids contents (TFC), and total condensed tannins (TCT)), antioxidant activity (i.e., DPPH, β-carotene & ABTS⁺ assays), moisture contents, water activity (aw), solubility, hygroscopicity, glass transition temperature (Tg), particle size, morphology, in vitroα-amylase and α-glucosidase inhibition and bioavailability ratios of the powders were investigated. Amongst all encapsulated products, TB (5% GA & 5% MD) and TC (10% GA) have proven to be the best treatments with respect to the highest preservation of antioxidant components. These treatments also exhibited higher antioxidant potential by DPPH and β-carotene assays and noteworthy for an ABTS⁺ assays. Moreover, the aforesaid treatments also demonstrated lower moisture content, aw, particle size and higher solubility, hygroscopicity and glass transition temperature (Tg). All freeze dried samples showed irregular (asymmetrical) microcrystalline structures. Furthermore, TB and TC also illustrated the highest in vitro anti-diabetic potential due to great potency for inhibiting α-amylase and α-glucosidase activities. In the perspective of bioavailability, TA, TB and TC demonstrated the excellent bioavailability ratios (%). Furthermore, the photochemical profiling of ethanolic extract of PHF was also revealed to find out the bioactive compounds.

Dengue Virus and Its Inhibitors: A Brief Review

The global occurrence of viral infectious diseases poses a significant threat to human health. Dengue virus (DENV) infection is one of the most noteworthy of these infections. According to a WHO survey, approximately 400 million people are infected annually; symptoms deteriorate in approximately one percent of cases. Numerous foundational and clinical investigations on viral epidemiology, structure and function analysis, infection source and route, therapeutic targets, vaccines, and therapeutic drugs have been conducted by both academic and industrial researchers. At present, CYD-TDV or Dengvaxia^® is the only approved vaccine, but potent inhibitors are currently under development. In this review, an overview of the viral life circle and the history of DENVs is presented, and the most recently reported antiviral candidates and newly discovered promising targets are focused and summarized. We believe that these successes and failures have enabled progress in anti-DENV drug discovery and hope that our review will stimulate further innovation in this area.

Tatanan A from the Acorus calamus L. root inhibited dengue virus proliferation and infections

BACKGROUND

Acorus calamus l. (Acoraceae) is a well-known traditional Chinese medicinal plant, whose root are historically mainly used to treat neurodegenerative diseases, and for cholera treatment. This datum strongly indicates the antimicrobial activity of A. calamus.

PURPOSE

Our goal is to find the active constituents of A. calamus to treat dengue virus (DENV) infections, and to study the effects and mechanisms of these active substances.

METHODS

The root of A. calamus was extracted by ethanol. Mosquito larva C6/36 cells were used for DENV2 replication and transfection host. Mouse kidney fibroblast cells (BHK-21) were used as a host cell to study the infection ability of the virus. DENV2-induced cytopathic effect (CPE) and plaque assay were used to evaluate the inhibitory effect of A. calamus extracts on DENV2 infectivity inhibition. The levels of E and NS1 protein expression were measured by real-time PCR and western blot assays.

RESULTS

12 compounds were isolated from ethanol extract of A. calamus root, tatanan A showed the best anti-DENV ability among these 12 compounds, which significantly alleviated DENV2-induced CPE and cytotoxicity effects, with an EC₅₀ of 3.9 µM. In addition, RNA replication assay further confirmed the antivirus ability of tatanan A. Time-addition assay showed that tatanan A affected the early stage of viral RNA replication, which in turn inhibited mRNA and protein levels of DENV2.

CONCLUSIONS

These results demonstrated the anti-DENV2 effect of tatanan A, in inhibiting DENV2 RNA replication and infections. In summary, tatanan A was found to be a novel natural DENV inhibitor and a potential candidate for the treatment of DENV infectious disease.

Anti-viral Activities of Oroxylum indicum Extracts on Chikungunya Virus Infection

Chikungunya virus (CHIKV) is a re-emerging mosquito-borne alphavirus that poses a threat to human worldwide. Driven by the lack of approved medication and vaccination, research on anti-Chikungunya agents has received great attention. In an effort to determine potential inhibitor of CHIKV, this study aimed at investigating the potential anti-viral activity of Oroxylum indicum extracts towards CHIKV-infected Vero cells. The virucidal, pre- and post-treatment effects of O. indicum were evaluated, using the maximum non-toxic dose of O. indicum methanol and aqueous extracts as determined by cytotoxicity assay. The viral inhibitory effect was assessed by the morphological changes of Vero cells and further confirmed by plaque assay. Both methanol and aqueous extracts of O. indicum had similar cytotoxicity in Vero cells. Interestingly, the virucidal effect of O. indicum aqueous extract revealed a significant reduction on the viral titre (p < 0.05). The prophylactic effect of aqueous extract was demonstrated when the pre-treated cells exhibited a significant anti-CHIKV activity (p < 0.05). However, methanol extract of this plant exerted an anti-viral activity against CHIKV only to a certain extent. Therefore, the aqueous extract of this plant has a potential to inhibit the virus and acts as prophylactic agent against CHIKV. Further studies however are needed to substantiate the finding and to determine the important compound of this plant as well as the mechanism of action in treating CHIKV infection.

Molecular docking, QSAR and ADMET based mining of natural compounds against prime targets of HIV

AIDS is one of the multifaceted diseases and this underlying complexity hampers its complete cure. The toxicity of existing drugs and emergence of multidrug-resistant virus makes the treatment worse. Development of effective, safe and low-cost anti-HIV drugs is among the top global priority. Exploration of natural resources may give ray of hope to develop new anti-HIV leads. Among the various therapeutic targets for HIV treatment, reverse transcriptase, protease, integrase, GP120, and ribonuclease are the prime focus. In the present study, we predicted potential plant-derived natural molecules for HIV treatment using computational approach, i.e. molecular docking, quantitative structure activity relationship (QSAR), and ADMET studies. Receptor-ligand binding studies were performed using three different software for precise prediction - Discovery studio 4.0, Schrodinger and Molegrow virtual docker. Docking scores revealed that Mulberrosides, Anolignans, Curcumin and Chebulic acid are promising candidates that bind with multi targets of HIV, while Neo-andrographolide, Nimbolide and Punigluconin were target-specific candidates. Subsequently, QSAR was performed using biologically proved compounds which predicted the biological activity of compounds. We identified Anolignans, Curcumin, Mulberrosides, Chebulic acid and Neo-andrographolide as potential natural molecules for HIV treatment from results of molecular docking and 3D-QSAR. In silico ADMET studies showed drug-likeness of these lead molecules. Structure similarities of identified lead molecules were compared with identified marketed drugs by superimposing both the molecules. Using in silico studies, we have identified few best fit molecules of natural origin against identified targets which may give new drugs to combat HIV infection after wet lab validation.

Anti-dengue activity of Andrographis paniculata extracts and quantification of dengue viral inhibition by SYBR green reverse transcription polymerase chain reaction

Background:

Dengue virus is a leading cause of illness and death in the tropics and subtropics. As many as 400 million people are infected yearly. Dengue is caused by any one of four related viruses transmitted by mosquitoes. Currently, there is no vaccine to prevent infection with dengue virus and the most effective protective measures are those that avoid mosquito bites. When infected, early recognition and prompt supportive treatment can substantially lower the risk of medical complications and death. Nowadays, the search for natural plant products to fight against viral diseases has been increasing.

Aims and Objective:

To test the anti-dengu viral activity of both ethanolic & aqueous extract of Andrographis paniculata.

Materials and Methods:

In vitro antiviral activity were performed against dengue virus by the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method and SYBR green quantitative real-time polymerase chain reaction (PCR) method. Cytotoxicity was also evaluated by MTT. The dengue viral load (VL) inhibition in plant extracts was characterized by reverse transcription PCR (RT-PCR) analysis.

Results and Discussion:

In this study, the maximum nontoxic dose (MNTD) of A. paniculata plant was determined by testing the ethanolic extracts against Vero cells in vitro. Antiviral assay based on cytopathic effects denoted by degree of inhibition upon treating DENV 1–4-infected Vero cells with MNTD of A. paniculata has the most antiviral inhibitory effects. These results were further verified with an in vitro inhibition assay using MTT and RT-PCR, in which 55%–97% of cell viability were recorded in DENV-1–4-infected cells in different duration.

Conclusion:

Ethanolic extracts treated with dengue VLs also showed a significant changes which were reflected in RT PCR assay.

Potential of selected Lamiaceae plants in anti(retro)viral therapy

Constant search for new drugs with antiviral properties often extends to products of natural origin. Lamiaceae is one of the most important herbal families, well known for various biological and medicinal effects of a variety of aromatic spices, including thyme, mint, oregano, basil, sage, savory, rosemary, self-heal, hyssop, lemon balm and many others. The paper provides a review of antiviral potential of previously mentioned plants which has been demonstrated so far, with special emphasis on anti-HIV properties. Relevant articles were compiled by searching plant names combined with keywords describing antiviral activity. The antiviral effect is direct, with prominent activity against enveloped viral species. Initial stages of the viral life cycle are the most affected, as these plants appear to be targeting mainly viral structures responsible for attachment to target cells. In case of HIV, there is some activity against key enzymes in the viral life cycle. Even in the case of drug resistance, there is an equal susceptibility to applied herbal preparations. Some in vivo experiments suggest that use of Lamiaceae representatives could help in prevention and treatment of some viral diseases. A possible reduction of side effects of diseases and conventional drug therapy are also some aspects worth further investigations.

Ghost probiotics with a combined regimen: a novel therapeutic approach against the Zika virus, an emerging world threat

The Zika virus (ZIKV) used to be an obscure flavivirus closely related to dengue virus (DENV). Transmission of this epidemic pathogen occurs mainly via mosquitoes, but it is also capable of placental and sexual transmission. Although the characteristics of these viruses are well defined, infections are unpredictable in terms of disease severity, unusual clinical manifestations, unexpected methods of transmission, long-term persistence, and the development of new strains. Recently, ZIKV has gained huge medical attention following the large-scale epidemics around the world, and reported cases of congenital abnormalities associated with Zika virus infections which have created a public health emergency of international concern. Despite continuous research on ZIKV, no specific treatment or vaccine has been developed, excepting a preventive strategy for congenital ZIKV infection. Probiotics, known as GRAS, are bacteria that confer various health beneficial effects, and have been shown to be effective at curing a number of viral diseases by modulating the immune system. Furthermore, probiotic preparations consisting of dead cells and cellular metabolites, so-called "Ghost probiotics", can also act as biological response modifiers. Here, we review available information on the epidemiology, transmission, and clinical features of ZIKV, and on treatment and prevention strategies. In addition, we emphasize the use of probiotics and plant-based natural remedies and describe their action mechanisms, and the green technologies for microbial conversion, which could contribute to the development of novel therapies that may reduce the pathogenicity of ZIKV. Accordingly, we draw attention to new findings, unanswered questions, unresolved issues, and controversies regarding ZIKV.