Antiviral properties of ent-labdene diterpenes ofAndrographis paniculata nees, inhibitors of herpes simplex virus type 1

Study of andrographolide bioactivity against Pseudomonas aeruginosa based on computational methodology and biochemical analysis

Andrographolide is one of the main biologically active molecules isolated from Andrographis paniculata (A. paniculata), which is a traditional Chinese herb used extensively throughout Eastern Asia, India, and China. Pseudomonas aeruginosa, often known as P. aeruginosa, is a common clinical opportunistic pathogen with remarkable adaptability to harsh settings and resistance to antibiotics. P. aeruginosa possesses a wide array of virulence traits, one of which is biofilm formation, which contributes to its pathogenicity. One of the main modulators of the P. aeruginosa-controlled intramembrane proteolysis pathway is AlgW, a membrane-bound periplasmic serine protease. In this work, we have used a set of density functional theory (DFT) calculations to understand the variety of chemical parameters in detail between andrographolide and levofloxacin, which show strong bactericidal activity against P. aeruginosa. Additionally, the stability and interaction of andrographolide and levofloxacin with the protein AlgW have been investigated by molecular docking and molecular dynamics (MD) simulations . Moreover, the growth and inhibition of biofilm production by P. aeruginosa experiments were also investigated, providing insight that andrographolide could be a potential natural product to inhibit P. aeruginosa.

Andrographis paniculata and Andrographolide - A Snapshot on Recent Advances in Nano Drug Delivery Systems against Cancer

Cancer is one of the deadliest illnesses of the 21st century. Chemotherapy and radiation therapies both have considerable side effects. Antitumor antibiotics are one of them. Coughs, common colds, fevers, laryngitis, and infectious disorders have all been treated with Andrographis paniculata for centuries. Extracts of Andrographis effectively treat various ailments, as well as cancer. The most active molecule in Andrographis paniculata is andrographolide a, diterpene, and lactone. Andrographis paniculata and its derivatives have long been used to treat various ailments. Anti-inflammatory and cancerfighting characteristics have been observed in Andrographolide. Andrographolide, a diterpene lactone separated from Andrographis paniculata, has also been shown to have important criticalessential biological protective properties. It has also been suggested that it could be used to treat major human diseases like-rheumatoid like rheumatoid, colitis, and Parkinsons disease. This summary aims to highlight Andrographolide as a promising cancer treatment option. Several databases were searched for andrographolides cytotoxic/anti-cancer effects in pre-clinical and clinical research to serve this purpose. Several studies have shown that Andrographolide is helpful in cancer medication, as detailed in this review.

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.

Antihyperglycemic activity of 14-deoxy, 11, 12-didehydro andrographolide on streptozotocin-nicotinamide induced type 2 diabetic rats

BACKGROUND

Diabetic Mellitus is characterized by a lack or failure of insulin to bind to its target receptor or failure of the pancreas to yield insulin. This study evaluated the antihyperglycemic activity of 14-deoxy, 11, 12-didehydro andrographolide on streptozotocin-nicotinamide-induced type 2 diabetic rats. Diabetic conditions were induced by administering streptozotocin at a dosage of 45 mg/kg body weight and nicotinamide at a dosage of 110 mg/kg body weight through intraperitoneal injection.

MATERIALS AND METHODS

Diabetic-induced rats were treated with 14-deoxy, 11, 12-didehydro andrographolide concentrations between 10 and 500 mg/kg body weight. The blood glucose level and body weight of the rats were periodically examined. The pancreas was isolated and the histopathological staining was performed after making fine sections of the pancreas using a microtome. The influence of 14-deoxy, 11, 12-didehydro andrographolide on the expression level of various insulin signaling cascades was determined with q-PCR and western blotting.

RESULTS

The blood glucose level of the diabetic-induced rats was significantly (p < 0.05) higher when compared with the control group and resulted in a drop in the blood glucose level of the diabetic rats. Oral glucose level was also reduced in the treatment group and no significant reduction was noted in the untreated. The lipid profiling revealed that the atherogenic index and cholesterol ratio was increased in the diabetic group over the control group. Upregulation of the insulin cascades like IRTK and GLUT4 was observed by the q-PCR and upregulation of GLUT4 and IR-β was observed by the western blot analysis.

CONCLUSION

Overall, the finding indicates that 14-deoxy, 11, 12-didehydro andrographolide exhibited antihyperglycemic activity by modulating the expression of insulin cascades.

A Reappraisal of the Antiviral Properties of and Immune Regulation through Dietary Phytochemicals

In the present era of the COVID-19 pandemic, viral infections remain a major cause of morbidity and mortality worldwide. In this day and age, viral infections are rampant and spreading rapidly. Among the most aggressive viral infections are ebola, AIDS (acquired immunodeficiency syndrome), influenza, and SARS (severe acute respiratory syndrome). Even though there are few treatment options for viral diseases, most of the antiviral therapies are ineffective owing to frequent mutations, the development of more aggressive strains, drug resistance, and possible side effects. Traditionally, herbal remedies have been used by healers, including for dietary and medicinal purposes. Many clinical and scientific studies have demonstrated the therapeutic potential of plant-derived natural compounds. Because of unsafe practices like blood transfusions and organ transplants from infected patients, medical supply contamination. Our antiviral therapies cannot achieve sterile immunity, and we have yet to find a cure for these pernicious infections. Herbs have been shown to improve therapeutic efficacy against a wide variety of viral diseases because of their high concentration of immunomodulatory phytochemicals (both immunoinhibitory and anti-inflammatory). Combined with biotechnology, this folk medicine system can lead to the development of novel antiviral drugs and therapies. In this Review, we will summarize some selected bioactive compounds with probable mechanisms of their antiviral actions, focusing on the immunological axis of these compounds.

The Potential of Ameliorating COVID-19 and Sequelae From Andrographis paniculata via Bioinformatics

The current coronavirus disease 2019 (COVID-19) outbreak is alarmingly escalating and raises challenges in finding efficient compounds for treatment. Repurposing phytochemicals in herbs is an ideal and economical approach for screening potential herbal components against COVID-19. Andrographis paniculata, also known as Chuan Xin Lian, has traditionally been used as an anti-inflammatory and antibacterial herb for centuries and has recently been classified as a promising herbal remedy for adjuvant therapy in treating respiratory diseases. This study aimed to screen Chuan Xin Lian's bioactive components and elicit the potential pharmacological mechanisms and plausible pathways for treating COVID-19 using network pharmacology combined with molecular docking. The results found terpenoid (andrographolide) and flavonoid (luteolin, quercetin, kaempferol, and wogonin) derivatives had remarkable potential against COVID-19 and sequelae owing to their high degrees in the component-target-pathway network and strong binding capacities in docking scores. In addition, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that the PI3K-AKT signaling pathway might be the most vital molecular pathway in the pathophysiology of COVID-19 and long-term sequelae whereby therapeutic strategies can intervene.

Synthesis of deoxy-Andrographolide Triazolyl Glycoconjugates for the Treatment of Alzheimer's Disease

A new andrographolide-based terminal alkyne 3 was synthesized in good yield from deoxy-andrographolide 2, obtained from a natural compound andrographolide 1, which in turn was isolated from the leaves of the plant Andrographis paniculata. Copper(I)-catalyzed azide-alkyne cycloaddition reaction of alkyne 3 with azido-sugars 4a-f furnished a library of andrographolide-fastened triazolyl glycoconjugates 5a-f in good yields. The structures of these semisynthetic andrographolide derivatives were established by Fourier transform infrared, NMR, and mass spectroscopy. The compounds 5a-f were further evaluated against Alzheimer's disease (AD) using a scopolamine (SCOP)-induced memory impairment mice model. It was observed that antioxidant and anticholinesterase properties of these compounds contribute significantly toward their remarkable potential to improve cognitive functioning.

The antithrombosis effect of dehydroandrographolide succinate: in vitro and in vivo studies

CONTEXT

Dehydroandrographolide succinate (DAS) is mainly used in the clinical treatment of various infectious diseases. Its potential effects on platelet aggregation and blood coagulation systems have not been reported systematically.

OBJECTIVE

To explore whether DAS exerts an antithrombotic effect and its internal mechanism.

MATERIALS AND METHODS

Human blood samples and Sprague-Dawley (SD) rats divided into control, aspirin (30 mg/kg), and DAS groups (200, 400 and 600 mg/kg) were used to measure the platelet aggregation rate, coagulation function, coagulation factor activity, and contents of thromboxane B₂ (TXB₂) and 6-keto-prostaglandin F_1α (6-keto-PGF_1α). The histopathology of the SD rat gastric mucosa was also observed. All rats were administered intragastric or intraperitoneal injections once a day for 3 consecutive days.

RESULTS

Compared to control group, DAS significantly inhibited the platelet aggregation rate (ED₅₀ = 386.9 mg/kg) by decreasing TXB₂ levels (1531.95 ± 649.90 pg/mL to 511.08 ± 411.82 pg/mL) and activating antithrombin III (AT-III) (103.22 ± 16.22% to 146.46 ± 8.96%) (p < 0.05). In addition, DAS significantly enhanced the coagulation factors FV (304.12 ± 79.65% to 443.44 ± 75.04%), FVII (324.19 ± 48.03% to 790.66 ± 225.56%), FVIII (524.79 ± 115.47% to 679.92 ± 143.34%), FX (34.90 ± 7.40% to 102.76 ± 29.41%) and FXI (38.12 ± 10.33% to 65.47 ± 34.08%), increased the content of Fg (2.18 ± 0.39 to 3.61 ± 0.37 g/L), shorten the PT (10.42 ± 0.44 to 9.22 ± 0.21 s), APTT (16.43 ± 1.4 to 14.07 ± 0.75 s) and TT time (37.04 ± 2.13 to 32.68 ± 1.29 s) (p < 0.05), while the aspirin group showed no such effect on these items but showed reduced activity of FII (89.21 ± 21.72% to 61.83 ± 8.95%) and FVIII (524.79 ± 115.47% to 306.60 ± 29.96%) (p < 0.05). Histopathological changes showed aspirin-induced gastric mucosa haemorrhage and the protective effect of DAS in the gastric mucosa.

CONCLUSIONS

DAS is more suitable than aspirin in thromboprophylaxis treatment, which provides a reliable theoretical and experimental basis for its clinical application.

Recent advances in natural products as potential inhibitors of dengue virus with a special emphasis on NS2b/NS3 protease

Dengue virus (DENV) is an arbovirus widespread through tropical and subtropical areas. It is transmitted to humans through Aedes mosquitoes. Infections with DENV can lead to a series of complications, including dengue fever, dengue haemorrhagic fever, or dengue shock syndrome, which might manifest through secondary infections because of a vulnerable immune system. To date, only one tetravalent DENV vaccine is approved to be administered to children whom have been previously DENV-infected and between 9 and 16 years of age. One of the key targets in discovering DENV antiviral agents is the NS2b/NS3 protease. This protease is a crucial enzyme complex for the proteolytic and cleavage activities of the translated polyprotein during DENV life cycle. Several studies were conducted to discover potential antivirals from natural sources or synthetic compounds and peptides. In this review, we describe the recent studies from the past five years dealing with isolated natural products as potential inhibitors of DENV with a greater focus on inhibiting the NS2b/NS3 protease. This review describes recent discoveries in anti-DENV potential of isolated phytochemicals belonging to different groups including fatty acids, glucosides, terpenes and terpenoids, flavonoids, phenolics, chalcones, acetamides, and peptides. Curcumin, quercetin, and myricetin were found to act as non-competitive inhibitors for the NS2b/NS3 protease enzyme. In some studies, the molecular targets of some of these compounds are yet to be identified using in-silico and in-vitro approaches. So far, none of the isolated natural products was tested clinically for the management of DENV infections. The discussed studies demonstrate that natural products are a rich source of potential anti-DENV compounds. However, not all of these compounds were studied for their kinetic molecular mechanism and type of inhibition. In-silico studies provided an ample number of phytochemical hits to be tested experimentally as DENV protease inhibitors. In conclusion, derivatives of these natural products can be designed and synthesised, which could enhance their specificity and efficacy towards the protease. Other sources of natural products, such as fungi, bacterial toxins, marine organisms, and animals, should also be explored towards discovering more potential and effective DENV NS2b/NS3 protease inhibitors.

Andrographolide and Deoxyandrographolide Inhibit Protease and IFN-Antagonist Activities of Foot-and-Mouth Disease Virus 3Cpro

Simple Summary

Foot-and-Mouth disease (FMD) is a re-emerging infectious disease that poses a negative impact on livestock production and economics worldwide. It is also endemic in underdeveloped and developing countries, mostly in tropical areas. The control of this highly contagious disease requires a combination of different strategies, including the culling of infected animals, reducing animal movement, and vaccination. Although vaccination is effective, there remains a non-protective interval after immunization. Antiviral agents that can inhibit FMD virus (FMDV) could reduce the shedding of viruses in terms of quantity and duration, which could assist other control measures to contain FMD spreading. Antiviral activities of plant-based products, including andrographolides, have been demonstrated in several studies. Andrographolides are a group of phytochemical compounds derived from medicinal plants in the genus Andrographis, which are abundant in Asia, a hot spot of FMDV outbreaks. We found that andrographolides could inhibit FMDV replication by targeting a viral protease, namely 3C^pro. FMDV 3C^pro is the main protease essential for the virus life cycle. The 3C^pro also counteracts type I interferon, which is the frontline antiviral cytokine. We also revealed the intracellular mechanisms by which the andrographolides inhibited both protease and IFN antagonist activities of the 3C^pro.

Abstract

Foot-and mouth-disease (FMD) caused by the FMD virus (FMDV) is highly contagious and negatively affects livestock worldwide. The control of the disease requires a combination of measures, including vaccination; however, there is no specific treatment available. Several studies have shown that plant-derived products with antiviral properties were effective on viral diseases. Herein, antiviral activities of andrographolide (AGL), deoxyandrographolide (DAG), and neoandrographolide (NEO) against FMDV serotype A were investigated using an in vitro cell-based assay. The results showed that AGL and DAG inhibited FMDV in BHK-21 cells. The inhibitory effects of AGL and DAG were evaluated by RT-qPCR and exhibited EC50 values of 52.18 ± 0.01 µM (SI = 2.23) and 36.47 ± 0.07 µM (SI = 9.22), respectively. The intracellular protease assay revealed that AGL and DAG inhibited FMDV 3C^pro with IC50 of 67.43 ± 0.81 and 25.58 ± 1.41 µM, respectively. Additionally, AGL and DAG significantly interfered with interferon (IFN) antagonist activity of the 3C^pro by derepressing interferon-stimulating gene (ISGs) expression. The molecular docking confirmed that the andrographolides preferentially interacted with the 3C^pro active site. However, NEO had no antiviral effect in any of the assays. Conclusively, AGL and DAG inhibited FMDV serotype A by interacting with the 3C^pro and hindered its protease and IFN antagonist activities.

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.

Development of Synergy-Based Combination of Methanolic Extract of Andrographis paniculata and Berberis aristata Against E. coli and S. aureus

This study evaluates the antibacterial activity and phytochemical characterizations of Andrographis paniculata extract (APE) and Berberis aristata extract (BAE). The stem of Andrographis paniculata (AP) and root of Berberis aristata (BA) were extracted with methanol. The results confirmed that APE and BAE possess high phenolic and flavonoid content. The antioxidant activity of the APE and BAE showed an elevated potential to scavenge DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals with IC₅₀ of 95.03 μg/mL and 256.26 μg/mL, respectively. A total of 35 and 32 metabolites in APE and BAE, respectively, were identified through mass spectrometry analysis, whereas 17 and 12 metabolites in APE and BAE, respectively, were detected through high-performance thin-layer chromatography (HPTLC) fingerprinting profiling. Antibacterial activity of the extracts was performed by the well diffusion and microdilution method, and the findings showed that APE and BAE had antibacterial activities against E. coli and S. aureus. The growth curve and time-kill study showed that the extracts had a bacteriostatic effect. A combination study with the standard drug was carried out using the microdilution checkerboard method in which most of the combinations showed synergistic interactions. The findings of this study have shown that APE and BAE are good sources of antibacterial compounds and can be used for treating infectious diseases caused by E. coli and S. aureus.

A comprehensive review on facemask manufacturing, testing, and its environmental impacts

The coronavirus pandemic (COVID-19) is currently the biggest threat to human lives due to its rapid transmission rate causing severe damage to human health and economy. The transmission of viral diseases can be minimized at its early stages with proper planning and preventive practices. The use of facemask has proved to be most effective measure to curb the spread of virus along with social distancing and good hygiene practices. This necessitates more research on facemask technology to increase its filtration efficiencies and proper disposal, which can be accelerated with knowledge of the current manufacturing process and recent research in this field. This review article provides an overview of the importance of facemask, fundamentals of nonwoven fabrics, and its manufacturing process. It also covers topics related to recent research reported for improved facemask efficiencies and testing methods to evaluate the performance of facemask. The plastic waste associated with the facemask and measures to minimize its effect are also briefly described. A systematic understanding is given in order to trigger future research in this field to ensure that we are well equipped for any future pandemic.

Andrographis paniculata mitigates first-line anti-tubercular drugs-induced nephrotoxicity in Wistar rats

CONTEXT

Anti-tubercular drugs (ATDs) mediated adverse drug reactions are major concerns for clinicians to treat tuberculosis infection. This study aimed to investigate Andrographis paniculata extract-based phytotherapy to combat the nephrotoxic effects caused by ATDs therapy.

METHODS

Reno-protective effect of A. paniculata extract in ATDs-induced rats was evaluated through LPO, GSH, CAT, SOD, GST, urea, creatinine, uric acid, and histopathological studies. Standardization of the extract was performed RP-HPLC and FTIR analysis. Whereas, the effect of A. paniculata extract on ATDs induced genetic perturbation was analyzed using micronucleus assay. Moreover, the expression level of the xenometabolic gene was investigated using RT-PCR to explore the therapeutic mechanism.

RESULTS

The nephrotoxic effect of ATDs was indicated by elevated levels of LPO and renal function markers along with the reduced activity of renal antioxidants. An up-regulated expression profile of NAT gene and histological alterations were observed in renal tissue however, micronucleated PCEs were observed in bone marrow cells. Concomitant treatment with A. paniculata extract revealed a noticeable amelioration of elevated oxidative stress markers, gene expression levels, genotoxic perturbation, and histological alterations in a dose-dependent manner.

CONCLUSION

Hence, the present study using A. paniculata leaf extract confirmed to play effective phytotherapy against ATDs induced renal toxicity.

Discovery of Novel Andrographolide Derivatives as Antiviral Inhibitors against Human Enterovirus A71

Hand-foot-and-mouth disease (HFMD) caused by human enterovirus A71 (EV-A71) infection has been associated with severe neurological complications. With the lack of an internationally approved antiviral, coupled with a surge in outbreaks globally, EV-A71 has emerged as a neurotropic virus of high clinical importance. Andrographolide has many pharmacological effects including antiviral activity and its derivative, andrographolide sulfonate, has been used in China clinically to treat EV-A71 infections. This study sought to identify novel andrographolide derivatives as EV-A71 inhibitors and elucidate their antiviral mode of action. Using an immunofluorescence-based phenotypic screen, we identified novel EV-A71 inhibitors from a 344-compound library of andrographolide derivatives and validated them with viral plaque assays. Among these hits, ZAF-47, a quinolinoxy-andrographolide, was selected for downstream mechanistic studies. It was found that ZAF-47 acts on EV-A71 post-entry stages and inhibits EV-A71 protein expression. Subsequent luciferase studies confirm that ZAF-47 targets EV-A71 genome RNA replication specifically. Unsuccessful attempts in generating resistant mutants led us to believe a host factor is likely to be involved which coincide with the finding that ZAF-47 exhibits broad-spectrum antiviral activity against other enteroviruses (CV-A16, CV-A6, Echo7, CV-B5, CV-A24 and EV-D68). Furthermore, ZAF-46 and ZAF-47, hits from the screen, were derivatives of the same series containing quinolinoxy and olefin modifications, suggesting that an andrographolide scaffold mounted with these unique moieties could be a potential anti-EV-A71/HFMD strategy.

Isolation and Identification of Andrographis paniculata (Chuanxinlian) and Its Biologically Active Constituents Inhibited Enterovirus 71-Induced Cell Apoptosis

Aim:Andrographis paniculata (Burm. f.) Nees (also known as Chuanxinlian in Chinese) of Acanthaceae family is one of the Chinese herbs reputed to be effective in the treatment of inflammation, infection, cold, and fever. Enterovirus 71 (EV71) is one of the most important enteroviruses that cause hand, foot, and mouth disease (HFMD) accompanied with neurological complication.

Methods: To explore an anti-infective Chinese herb medicine, pure compounds isolated or synthesized analogues from A. paniculata (AP) ethyl acetate (EtOAc) extract are used to explore their anti-EV71-induced cytotoxicity. The antiviral activity was determined by cytopathic effect (CPE) reduction, and sub-G1 assays were used for measuring lysis and apoptosis of EV71-infected rhabdomyosarcoma (RD) cells. IFNγ-driven luciferase reporter assay was used to evaluate their potential roles in activation of immune responses.

Results: Our data showed that EV71-induced sub-G1 phase of RD cells was dose dependently increased. Highly apoptotic EV71-infected RD cells were reduced by AP extract treatment. Ergosterol peroxide (4) has the most anti-apoptotic effect among these seven compounds. In addition, 3,19-O-acetyl-14-deoxy-11,12-didehydroandrographolide (8) synthesized from acetylation of compound 7 showed significantly better antiviral activity and the lowest sub-G1 phase of 6%–18%. Further investigation of IFNγ-inducer activity of these compounds showed that compounds 3, 6, 10, 11, and 12 had significantly higher IFNγ luciferase activities, suggesting their potential to promote IFNγ expression and thus activate immune responses for antivirus function.

Conclusion: Our study demonstrated that bioactive compounds of AP and its derivatives either protecting EV71-infected RD cells from sub-G1 arrest or possessing IFNγ-inducer activity might be feasible for the development of anti-EV71 agents.

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.

Azaadamantanes, a New Promising Scaffold for Medical Chemistry

Azaadamantanes are nitrogen-containing analogs of adamantane, which contain one or more nitrogen atoms instead of carbon atoms. This substitution leads to several specific chemical and physical properties. The azaadamantane derivatives have less lipophilicity compared to their adamantane analogs, which affects both their interaction with biological targets and bioavailability. The significant increase in the number of publications during the last decade (2009-2020) concerning the study of reactivity and biological activity of azaadamantanes and their derivatives indicates a great theoretical and practical interest in these compounds. Compounds with pronounced biological activity have been already discovered among azaadamantane derivatives. The review is devoted to the biological activity of azaadamantanes and their derivatives. It presents the main methods for the synthesis of di- and triazaadamantanes and summarizes the accumulated data on studying the biological activity of these compounds. The prospects for the use of azaadamantanes in medical chemistry and pharmacology are discussed.

Click chemistry inspired synthesis of andrographolide triazolyl conjugates for effective fluorescent sensing of ferric ions

The naturally occurring compound andrographolide 1 was used as a substrate for the synthesis of a novel terminal alkyne 3 which on copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction with azides 4a-l, 7 and 9 furnished a series of regioselective andrographolide triazolyl conjugates 5a-l, 8 and 10, respectively. A free glycoconjugate 6 was also prepared by selective deprotection of compound 5i in good yield. All the compounds were characterized by absorbance, FT-IR, NMR, and HR-MS analyses. The triazolyl conjugate 8 was further investigated as a probe for selective detection of Fe³⁺ ion in matrix. The mode of attachment of Fe³⁺ ion to the compound 8 was established by absorbance, fluorescence, infrared (IR), and nuclear magnetic resonance (NMR) spectroscopy, and high resolution mass-spectrometry (HR-MS). The logic gate circuits were constructed for the probe 8 and ethylenediaminetetraacetic acid (EDTA). The environmental perspective of probe 8 was investigated in real water samples.

Andrographolide Inhibits Lytic Reactivation of Epstein-Barr Virus by Modulating Transcription Factors in Gastric Cancer

Andrographolide is the principal bioactive chemical constituent of Andrographis paniculata and exhibits activity against several viruses, including Epstein–Barr virus (EBV). However, the particular mechanism by which andrographolide exerts an anti-EBV effect in EBV-associated gastric cancer (EBVaGC) cells remains unclear. We investigated the molecular mechanism by which andrographolide inhibits lytic reactivation of EBV in EBVaGC cells (AGS-EBV cell line) using proteomics and bioinformatics approaches. An andrographolide treatment altered EBV protein-expression patterns in AGS-EBV cells by suppressing the expression of EBV lytic protein. Interestingly cellular transcription factors (TFs), activators for EBV lytic reactivation, such as MEF2D and SP1, were significantly abolished in AGS-EBV cells treated with andrographolide and sodium butyrate (NaB) compared with NaB-treated cells. In contrast, the suppressors of EBV lytic reactivation, such as EZH2 and HDAC6, were significantly up-regulated in cells treated with both andrographolide and NaB compared with NaB treatment alone. In addition, bioinformatics predicted that HDAC6 could interact directly with MEF2D and SP1. Furthermore, andrographolide significantly induced cell cytotoxicity and apoptosis of AGS-EBV cells by induction of apoptosis-related protein expression. Our results suggest that andrographolide inhibits EBV lytic reactivation by inhibition of host TFs, partially through the interaction of HDAC6 with TFs, and induces apoptosis of EBVaGC cells.

A Review of Medicinal Plants with Antiviral Activity Available in Bangladesh and Mechanistic Insight Into Their Bioactive Metabolites on SARS-CoV-2, HIV and HBV

Currently, viral infection is the most serious health issue which causing unexpected higher rate of death globally. Many viruses are not yet curable, such as corona virus-2 (SARS-CoV-2), human immunodeficiency virus (HIV), hepatitis virus, human papilloma virus and so others. Furthermore, the toxicities and ineffective responses to resistant strains of synthetic antiviral drugs have reinforced the search of effective and alternative treatment options, such as plant-derived antiviral drug molecules. Therefore, in the present review, an attempt has been taken to summarize the medicinal plants reported for exhibiting antiviral activities available in Bangladesh along with discussing the mechanistic insights into their bioactive components against three most hazardous viruses, namely SARS-CoV-2, HIV, and HBV. The review covers 46 medicinal plants with antiviral activity from 25 families. Among the reported 79 bioactive compounds having antiviral activities isolated from these plants, about 37 of them have been reported for significant activities against varieties of viruses. Hesperidin, apigenin, luteolin, seselin, 6-gingerol, humulene epoxide, quercetin, kaempferol, curcumin, and epigallocatechin-3-gallate (EGCG) have been reported to inhibit multiple molecular targets of SARS-CoV-2 viral replication in a number of in silico investigations. Besides, numerous in silico, in vitro, and in vivo bioassays have been demonstrated that EGCG, anolignan-A, and B, ajoene, curcumin, and oleanolic acid exhibit anti-HIV activity while piperine, ursolic acid, oleanolic acid, (+)-cycloolivil-4'-O-β-d-glucopyranoside, quercetin, EGCG, kaempferol, aloin, apigenin, rosmarinic acid, andrographolide, and hesperidin possess anti-HBV activity. Thus, the antiviral medicinal plants and the isolated bioactive compounds may be considered for further advanced investigations with the aim of the development of effective and affordable antiviral drugs.

The Adroitness of Andrographolide as a Natural Weapon Against Colorectal Cancer

The conventional carcinoma treatment generally encompasses the employment of radiotherapy, chemotherapy, surgery or use of cytotoxic drugs. However, recent advances in pharmacological research have divulged the importance of traditional treatments in cancer. The aim of the present review is to provide an overview of the importance of one such medicinal herb of Chinese and Indian origin: Andrographis paniculate on colorectal cancer with special emphasis on its principal bioactive component andrographolide (AGP) and its underlying mechanisms of action. AGP has long been known to possess medicinal properties. Studies led by numerous groups of researchers shed light on its molecular mechanism of action. AGP has been shown to act in a multi-faceted manner in context of colorectal cancer by targeting matrix metalloproteinase-9, Toll-like receptor or NFκB signaling pathways. In this review, we highlighted the recent studies that show that AGP can act as an effective immunomodulator by harnessing effective anti-tumor immune response. Recent studies strongly recommend further research on this compound and its analogues, especially under in-vivo condition to assess its actual potential as a prospective and efficient candidate against colorectal cancer. The current review deals with the roles of this phytomedicine in context of colorectal cancer and briefly describes its perspectives to emerge as an essential anti-cancer drug candidate. Finally, we also point out the drawbacks and difficulties in administration of AGP and indicate the use of nano-formulations of this phytomedicine for better therapeutic efficacy.

Deciphering the potential anti-COVID-19 active ingredients in Andrographis paniculata (Burm. F.) Nees by combination of network pharmacology, molecular docking, and molecular dynamics

Currently, coronavirus disease 2019 (COVID-19) caused by Severe Acute Respiratory Syndrome Coronavirus 2 has posed an enormous threat to public health worldwide. An andrographolide sulfonates preparation, named Xiyanping injection in Chinese, which was prepared from the aqueous extract of Andrographis paniculata (Burm. F.) Nees, showed favorable therapeutic effectiveness on COVID-19, suggesting A. paniculata could contain powerful therapeutic ingredients against COVID-19. In this study, to search for the potential drug candidates for COVID-19 in the herb, 68 potential target proteins and 24 active ingredients from A. paniculata were screened out using TCMSP, STP, Genecards and TTD databases firstly. A. paniculata-Compound-Target network constructed by cytoscape software showed that the protein targets PTGS2, EGFR, MAPK14, etc. had a high network relevance value. GO and KEGG enrichment analysis indicated that the 24 compounds in A. paniculata might exert their therapeutic effects by the biological processes, cellular response to biotic stimulus, response to lipopolysaccharide, response to molecule of bacterial origin, etc. And AGE-RAGE signaling pathway in diabetic complications (hsa04933), Kaposi sarcoma-associated herpesvirus infection (hsa05167), Human cytomegalovirus infection (hsa05163), etc. were predicted as the most significant effect pathways. Andrographidine C (MOL008223) and andrographolide (MOL008232) were found with strong binding affinity to the target active sites of the potential targets by molecular docking. Ultimately, the application of molecular dynamics simulations demonstrated that andrographidine C could bind well to the ACE2 and PIK3CG proteins. This research identified novel molecules against COVID-19 for developing natural medicines from A. paniculate and also provides a possible explanation for the molecular mechanisms of Xiyanping Injection against COVID-19.

An integrated approach of network pharmacology, molecular docking and molecular dynamics to decipher the potential anti COVID-19 active ingredients in Andrographis paniculata (Burm. F.) Nees.

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.

Andrographolide and Its Derivative Potassium Dehydrographolide Succinate Suppress PRRSV Replication in Primary and Established Cells via Differential Mechanisms of Action

Porcine reproductive and respiratory syndrome virus (PRRSV) continues to cause significant economic loss worldwide and remains a serious threat to the pork industry. Currently, vaccination strategies provide limited protection against PRRSV infection, and consequently, new antiviral strategies are urgently required. Andrographolide (Andro) and its derivative potassium dehydrographolide succinate (PDS) have been used clinically in China and other Asian countries as therapies for inflammation-related diseases, including bacterial and viral infections, for decades. Here, we demonstrate that Andro and PDS exhibit robust activity against PRRSV replication in Marc-145 cells and primary porcine alveolar macrophages (PAMs). The two compounds exhibited broad-spectrum inhibitory activities in vitro against clinically circulating type 2 PRRSV GD-HD, XH-GD, and NADC30-like HNhx strains in China. The EC₅₀ values of Andro against three tested PRRSV strain infections in Marc-145 cells ranged from 11.7 to 15.3 μmol/L, with selectivity indexes ranging from 8.3 to 10.8, while the EC₅₀ values of PDS ranged from 57.1 to 85.4 μmol/L, with selectivity indexes ranging from 344 to 515. Mechanistically, the anti-PRRSV activity of the two compounds is closely associated with their potent suppression on NF-κB activation and enhanced oxidative stress induced by PRRSV infection. Further mechanistic investigations revealed that PDS, but not Andro, is able to directly interact with PRRSV particles. Taken together, our findings suggest that Andro and PDS are promising PRRSV inhibitors in vitro and deserves further in vivo studies in swine.

Andrographolide as a potent and promising antiviral agent

Andrographolide is a labdane diterpenoid extracted and purified from the aerial parts of plants belonging to genus Andrographis (Acanthaceae). The research has shown the plant based compound is low cytotoxic, having antimicrobial, anti-cancer, antiviral and anti-parasitic effects. Andrographolide both prevent spread as well as transmission of virus to neighboring cells by interfering with different cell signaling pathways. In addition to its medicinal value, plant has been found having nutritional value. Therefore being cost effective, easy availability and having nutritional value as a natural supplement, can be used to improve the quality of life in countries having low standard of living. Due to the limited number of effective vaccines, the plant-based antiviral drugs have provided considerable hope for fighting against the viral infections. The plant-derived compound when produced in large quantities is cost effective with low cytotoxic effects. However, much deep insight research at the molecular level is needed to develop the molecules against the viral infection. This paper aims to highlight the antiviral role of Andrographolide that can made significant contributions toward the improvement of human health and will also summarize the current status and future strategies concerning the therapeutic applications of Andrographolide to combat different viral disease in humans.

UGT86C11 is a novel plant UDP-glycosyltransferase involved in labdane diterpene biosynthesis

Glycosyltransferases constitute a large family of enzymes across all domains of life, but knowledge of their biochemical function remains largely incomplete, particularly in the context of plant specialized metabolism. The labdane diterpenes represent a large class of phytochemicals with many pharmacological benefits, such as anti-inflammatory, hepatoprotective, and anticarcinogenic. The medicinal plant kalmegh (Andrographis paniculata) produces bioactive labdane diterpenes; notably, the C19-hydroxyl diterpene (andrograpanin) is predominantly found as C19-O-glucoside (neoandrographolide), whereas diterpenes having additional hydroxylation(s) at C3 (14-deoxy-11,12-didehydroandrographolide) or C3 and C14 (andrographolide) are primarily detected as aglycones, signifying scaffold-selective C19-O-glucosylation of diterpenes in planta. Here, we analyzed UDP-glycosyltransferase (UGT) activity and diterpene levels across various developmental stages and tissues and found an apparent correlation of UGT activity with the spatiotemporal accumulation of neoandrographolide, the major diterpene C19-O-glucoside. The biochemical analysis of recombinant UGTs preferentially expressed in neoandrographolide-accumulating tissues identified a previously uncharacterized UGT86 member (ApUGT12/UGT86C11) that catalyzes C19-O-glucosylation of diterpenes with strict scaffold selectivity. ApUGT12 localized to the cytoplasm and catalyzed diterpene C19-O-glucosylation in planta. The substrate selectivity demonstrated by the recombinant ApUGT12 expressed in plant and bacterium hosts was comparable to native UGT activity. Recombinant ApUGT12 showed significantly higher catalytic efficiency using andrograpanin compared with 14-deoxy-11,12-didehydroandrographolide and trivial activity using andrographolide. Moreover, ApUGT12 silencing in plants led to a drastic reduction in neoandrographolide content and increased levels of andrograpanin. These data suggest the involvement of ApUGT12 in scaffold-selective C19-O-glucosylation of labdane diterpenes in plants. This knowledge of UGT86 function might help in developing plant chemotypes and synthesis of pharmacologically relevant diterpenes.

Andrographis paniculata (Burm.f.) Nees: Traditional uses, phytochemistry, pharmacological properties and quality control/quality assurance

ETHNOPHARMACOLOGICAL RELEVANCE

Andrographis paniculata (Burm.f.) Nees is a medicinal herb of the Asian countries used in many traditional medicinal systems for the treatment of diarrhea, flu, leprosy, leptospirosis, malaria, rabies, upper respiratory infections, sinusitis, syphilis, tuberculosis and HIV/AIDS etc. AIM OF THE STUDY: This review aims to provide the comprehensive, accurate and authentic information on traditional uses, phytochemistry and pharmacological properties of various extracts/fractions as well as phytocostituents of A. paniculata. In addition, this review also aims to provide advance and sensitive analytical methods along with chemical markers used in the standardization of herbal products for quality control (QC)/quality assurance (QA).

MATERIALS AND METHODS

All relevant publications were considered within the years 1983-2020. The publications were searched from Google Scholar, PubChem, Chemspider, PubMed, Elsevier, Wiley, Web of Science, China Knowledge Resource Integrated databases and ResearchGate using a combination of various relevant keywords. Besides, relevant published books and chapters were also considered those providing an overview of extant secondary literature related to traditional knowledge, phytochemistry, pharmacology and toxicity of the plant.

RESULTS AND DISCUSSION

In this review, 344 compounds, including, terpenoid lactones, flavonoids, phenolic acids, triterpenes and volatile compounds were summarized out of which more than half of the compounds have no reported pharmacological activities yet. Terpenoid lactones and flavonoids are the major bioactive classes of compounds of A. paniculata which are responsible for pharmacological activities such as anticancer and antioxidant activities, respectively. Biosynthetic pathways and active sites for target proteins of both terpenoid lactones and flavonoids were considered. Analgesic, anticancer, antidiabetic, antifertility, antiinflammatory, antimalarial, antimicrobial, antioxidant, antipyretic, antiviral, antiretroviral, antivenom, cardioprotective, hepatoprotective, immunomodulatory and neuroprotective activities have been also reported. Andrographolide is a major characteristic active principle and responsible for most of the pharmacological activities. Therefore, andrographolide has been selected as a marker for the standardization of raw and marketed herbal products by TLC, HPTLC, HPLC, GC-MS, HPLC-MS and HPLC-MS/MS methods for QC/QA.

CONCLUSIONS

Conclusive evidence showed that the pharmacological activities reported in crude extracts and chemical markers are supporting and provides confidence in the traditional use of A. paniculata as a herbal medicine. The andrographolide could be used as a chemical marker for the QC/QA of raw and A. paniculata derived herbal products. Lactone ring in terpenoid lactone is an active site for targeted proteins. More efforts should be focused on the identification of the chemical markers from A. paniculata to provide a practical basis for QC/QA. Several aspects such as the mechanism of therapeutic potential, molecular docking technology and multi-target network pharmacology are very important for drug discovery and needed more investigation and should be considered. This compilation may be helpful in further study and QC/QA.

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.

Anticancer potential of andrographolide from Andrographis paniculata (Burm.f.) Nees and its mechanisms of action

ETHNOPHARMACOLOGICAL RELEVANCE

Synthetic drugs used for cancer treatment have side effects that may be immunosupressive, can cause liver, kidney and cardiac toxicity, and infertility and ovarian failure, among others. Thus, herbal drugs could be used in the cancer treatment as an adjuvant therapy. Andrographis paniculata (Burm.f.) Nees (AP) is one of the traditional herbs used in different alternative medicinal systems such as Ayurveda, Unani, Chinese, Malayi, Siddha, etc. for the treatment of various disorders and diseases including cancer.

AIM OF THE STUDY

The aim of writing this review is to highlight the medicinal importance of AP and its main phytoconstituent andrographolide (AG). The main emphasis was given on the anticancer activity of AG, its proposed mechanisms of action, novel approaches used to improve its biopharmaceutical properties with the perspective of evidence-based research, and its development as an adjuvant therapy for cancer treatment in future.

MATERIALS AND METHODS

Literature survey was conducted and research papers were retrieved from different databases such as Pubmed, Google Scholar, ACS, Wiley online library, ScienceDirect, Springer, and Scopus during 1970-2020. Research articles, review articles, and short communications, etc. were used for this purpose. The papers were selected on the basis of exclusion and inclusion criteria.

RESULTS

Different anticancer mechanisms of AG have been reportedly proven such as cell cycle arrest, apoptosis, NF-κβ inhibition, antiangiogenesis, cytokine inhibition, etc. whereas its pharmacokinetic properties showed its highly protein bound nature, Cyt P400 (CYP) inhibition, low aqueous solubility, poor oral bioavailability, etc. Different novel formulations of AG have been investigated to increase its bioavailability for better efficacy.

CONCLUSION

This review can provide knowledge about the potential applicability of AP or AG as an adjuvant therapy in cancer treatment. Further research is needed before making any conclusion about the efficacy in humans as an adjuvant therapy in cancer.

Andrographis paniculata (Burm. F) Wall ex Nees: Antiviral properties

Andrographis paniculata is home to a rich variety of molecules especially andrographolide and its derivatives. Clinical properties of the andrographolide are multifarious and include: analgesic, antipyretic, antiretroviral, antiproliferative, antimalarial, antithrombotic, antihyperglycemic, antiurolethial, antilesihmaniasis, hepatoprotective, immune-modulatory, protective against alcohol induced toxicity and cardioproetcive activity and anticancer activity. Andrographolide, neoandrographolide, dehydroandrographolide and several natural and synthetic derivatives of it: 14-deoxy-11,12-didehydroandrographolide and 14-deoxyandrographolide, dehydroandrographolide succinic acid monoester (DAMS), 14-ά-lipoyl andrographolide (AL-1), 14-acetyl-3,9-isopropyl-ideneandrographolide, 14-acetylandrographolide, 3,14,19-triacetylandrographolide, and 3,9-isopropyl-idene andrographolide, are shown to possess significant antiviral activity against HIV, influenza A, HBV, HCV, HPP and HSV. Studies on SARS CoV 2 is restricted to in silico molecular docking studies on viral targets and selected host target proteins. The main targets of andrographolide and its derivatives are fusion and adsorption of virus to the host cell, binding to viral receptor and co-receptor, enzymes involved in DNA/RNA/Genome replication by the virus, translation, post-translation and reverse transcription. Andrographolide as a drug is yet to reach its full therapeutic potential since this molecule shows low bioavailability. Andrographolide therapy is in need of an appropriate delivery system that may increase its bioavailability. Further high-quality studies are needed to firmly establish the clinical efficacy of the plant.

Therapeutic Potentials of Antiviral Plants Used in Traditional African Medicine With COVID-19 in Focus: A Nigerian Perspective

The coronavirus disease 2019 (COVID-19) pandemic is caused by an infectious novel strain of coronavirus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which was earlier referred to as 2019-nCoV. The respiratory disease is the most consequential global public health crisis of the 21st century whose level of negative impact increasingly experienced globally has not been recorded since World War II. Up till now, there has been no specific globally authorized antiviral drug, vaccines, supplement or herbal remedy available for the treatment of this lethal disease except preventive measures, supportive care and non-specific treatment options adopted in different countries via divergent approaches to halt the pandemic. However, many of these interventions have been documented to show some level of success particularly the Traditional Chinese Medicine while there is paucity of well reported studies on the impact of the widely embraced Traditional African Medicines (TAM) adopted so far for the prevention, management and treatment of COVID-19. We carried out a detailed review of publicly available data, information and claims on the potentials of indigenous plants used in Sub-Saharan Africa as antiviral remedies with potentials for the prevention and management of COVID-19. In this review, we have provided a holistic report on evidence-based antiviral and promising anti-SARS-CoV-2 properties of African medicinal plants based on in silico evidence, in vitro assays and in vivo experiments alongside the available data on their mechanistic pharmacology. In addition, we have unveiled knowledge gaps, provided an update on the effort of African Scientific community toward demystifying the dreadful SARS-CoV-2 micro-enemy of man and have documented popular anti-COVID-19 herbal claims emanating from the continent for the management of COVID-19 while the risk potentials of herb-drug interaction of antiviral phytomedicines when used in combination with orthodox drugs have also been highlighted. This review exercise may lend enough credence to the potential value of African medicinal plants as possible leads in anti-COVID-19 drug discovery through research and development.

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.

Targeting Host Cellular Factors as a Strategy of Therapeutic Intervention for Herpesvirus Infections

Herpesviruses utilize various host factors to establish latent infection, survival, and spread disease in the host. These factors include host cellular machinery, host proteins, gene expression, multiple transcription factors, cellular signal pathways, immune cell activation, transcription factors, cytokines, angiogenesis, invasion, and factors promoting metastasis. The knowledge and understanding of host genes, protein products, and biochemical pathways lead to discovering safe and effective antivirals to prevent viral reactivation and spread infection. Here, we focus on the contribution of pro-inflammatory, anti-inflammatory, and resolution lipid metabolites of the arachidonic acid (AA) pathway in the lifecycle of herpesvirus infections. We discuss how various herpesviruses utilize these lipid pathways to their advantage and how we target them to combat herpesvirus infection. We also summarize recent development in anti-herpesvirus therapeutics and new strategies proposed or under clinical trials. These anti-herpesvirus therapeutics include inhibitors blocking viral life cycle events, engineered anticancer agents, epigenome influencing factors, immunomodulators, and therapeutic compounds from natural extracts.

Identification and characterization of new potent inhibitors of dengue virus NS5 proteinase from Andrographis paniculata supercritical extracts on in animal cell culture and in silico approaches

ETHNOPHARMACOLOGICAL RELEVANCE

About 2.5 billion peoples are at risk of dengue virus and the majority of people, use traditional plant-based medicines to combat dengue. The whole plant of Andrographis paniculata used traditionally over past decades for health promotion. Andrographolide isolated from Andrographis paniculata is used as natural remedy for the treatment of various diseases in different parts of the world. Andrographolide has been reported to have antiviral activity against hepatitis B virus, hepatitis C virus, herpes simplex virus, influenza virus, chikungunya virus, dengue virus 2 and 4.

AIM OF THE STUDY

The aim of the present study to isolate the andrographolide from the A. paniculata by supercritical fluid extraction technique and to characterize the isolated compound along with it anti-dengue activity against DENV-2 in vitro and in silico methods.

MATERIALS AND METHODS

Supercritical extraction condition for A. paniculata was standardised to isolate andrographolide compound at definite temperature and pressure on the basis of previous study. The andrographolide was identified by using Ultraviolet-Visible Spectroscopy (UV-VIS), Fourier-Transform Infrared Spectroscopy (FT-IR) and High Performance Thin Layer Chromatography (HPTLC) and Proton Nuclear Magnetic Resonance (¹HNMR). The maximum non-toxic dose of isolated andrographolide was detected by MTT assay using a micro plate reader at 595 nm. One hundred (100) copies/ml of the DENV-2 virus was used for antiviral assay in C6/36 cells lines and inhibition of virus due to andrographolide was determined by real-time PCR assay. The purity of isolated andrographolide was determined by Differential Scanning Calorimetry (DSC). The dengue NS5 receptor protein was docked with andrographolide and evaluated on the basis of the total energy and binding affinity score by Auto Dock (V4.2.6) software.

RESULTS

Andrographolide, a diterpene lactone was isolated from the A. paniculata supercritical extract at 40 °C temperature and 15 Mpa pressure. UV spectrophotometer analysis revealed that the curve of andrographolide plant extract was overlapped with reference compound at 228 nm and the similar bands were detected from FT-IR spectroscopy analysis at 3315, 2917, 2849, 1673, 1462 and 1454 cm^-1 in isolated and standard andrographolide. HPTLC analysis shows the retention factor (R_f) of A. paniculata extract at 0.74 ± 0.06 as similar to standard andrographolide R_f values. The purity of isolated andrographolide was 99.76%. The maximum non-toxic dose of isolated andrographolide was found as 15.62 μg/ml on the C6/36 cell line calculated by using MTT assay. The andrographolide showed the 97.23% anti-dengue activity against the dengue-2 virus in C6/36 cell lines. Results of molecular docking showed that the interaction between andrographolide and NS5 of dengue protein with the maximum binding energy as -7.35 kcal/mol.

CONCLUSIONS

It is concluded that isolated andrographolide from the A. paniculata possess anti-dengue activity against dengue-2 virus as revealed from in vitro and in silico method. Due to lack of the vaccine and anti-viral agents, andrographolide extracted from A. paniculata play a major role to inhibit the dengue replication. Hence, it could be a source for drug design and help to reduce the dengue infection.

A comprehensive review on antimicrobial face masks: an emerging weapon in fighting pandemics

The world has witnessed several incidents of epidemics and pandemics since the beginning of human existence. The gruesome effects of microbial threats create considerable repercussions on the healthcare systems. The continually evolving nature of causative viruses due to mutation or re-assortment sometimes makes existing medicines and vaccines inactive. As a rapid response to such outbreaks, much emphasis has been placed on personal protective equipment (PPE), especially face mask, to prevent infectious diseases from airborne pathogens. Wearing face masks in public reduce disease transmission and creates a sense of community solidarity in collectively fighting the pandemic. However, excessive use of single-use polymer-based face masks can pose a significant challenge to the environment and is increasingly evident in the ongoing COVID-19 pandemic. On the contrary, face masks with inherent antimicrobial properties can help in real-time deactivation of microorganisms enabling multiple-use and reduces secondary infections. Given the advantages, several efforts are made incorporating natural and synthetic antimicrobial agents (AMA) to produce face mask with enhanced safety, and the literature about such efforts are summarised. The review also discusses the literature concerning the current and future market potential and environmental impacts of face masks. Among the AMA tested, metal and metal-oxide based materials are more popular and relatively matured technology. However, the repeated use of such a face mask may pose a danger to the user and environment due to leaching/detachment of nanoparticles. So careful consideration is required to select AMA and their incorporation methods to reduce their leaching and environmental impacts. Also, systematic studies are required to establish short-term and long-term benefits.

Combination of system biology to probe the anti-viral activity of andrographolide and its derivative against COVID-19

The present study aimed to investigate the binding affinity of andrographolide and its derivative i.e., 14-deoxy-11,12-didehydroandrographolide with targets related to COVID-19 and their probable role in regulating multiple pathways in COVID-19 infection. SMILES of both compounds were retrieved from the PubChem database and predicted for probably regulated proteins. The predicted proteins were queried in STRING to evaluate the protein-protein interaction, and modulated pathways were identified concerning the KEGG database. Drug-likeness and ADMET profile of each compound was evaluated using MolSoft and admetSAR 2.0, respectively. Molecular docking was carried using Autodock 4.0. Andrographolide and its derivative were predicted to have a high binding affinity with papain-like protease, coronavirus main proteinase, and spike protein. Molecular dynamics simulation studies were performed for each complex which suggested the strong binding affinities of both compounds with targets. Network pharmacology analysis revealed that both compounds modulated the immune system by regulating chemokine signaling, Rap1 signaling, cytokine-cytokine receptor interaction, MAPK signaling, NF-kappa B signaling, RAS signaling, p53 signaling, HIF-1 signaling, and natural killer cell-mediated cytotoxicity. The study suggests strong interaction of andrographolide and 14-deoxy-11,12-didehydroandrographolide against COVID-19 associated target proteins and exhibited different immunoregulatory pathways.

Molecular Docking Studies on the Anti-viral Effects of Compounds From Kabasura Kudineer on SARS-CoV-2 3CLpro

The COVID-19 has now been declared a global pandemic by the World Health Organization. No approved drug is currently available; therefore, an urgent need has been developed for any antiviral therapy for COVID-19. Main protease 3CL^pro of this novel Coronavirus (SARS-CoV-2) play a critical role in the disease propagation, and hence represent a crucial target for the drug discovery. Herein, we have applied a bioinformatics approach for drug repurposing to identify the possible potent inhibitors of SARS-CoV-2 main proteases 3CL^pro (6LU7). In search of the anti-COVID-19 compound, we selected 145 phyto-compounds from Kabasura kudineer (KK), a poly-herbal formulation recommended by AYUSH for COVID-19 which are effective against fever, cough, sore throat, shortness of breath (similar to SARS-CoV2-like symptoms). The present study aims to identify molecules from natural products which may inhibit COVID-19 by acting on the main protease (3CL^pro). Obtained results by molecular docking showed that Acetoside (−153.06), Luteolin 7 -rutinoside (−134.6) rutin (−133.06), Chebulagic acid (−124.3), Syrigaresinol (−120.03), Acanthoside (−122.21), Violanthin (−114.9), Andrographidine C (−101.8), myricetin (−99.96), Gingerenone -A (−93.9), Tinosporinone (−83.42), Geraniol (−62.87), Nootkatone (−62.4), Asarianin (−79.94), and Gamma sitosterol (−81.94) are main compounds from KK plants which may inhibit COVID-19 giving the better energy score compared to synthetic drugs. Based on the binding energy score, we suggest that these compounds can be tested against Coronavirus and used to develop effective antiviral drugs.

Andrographolide and Its 14-Aryloxy Analogues Inhibit Zika and Dengue Virus Infection

Andrographolide is a labdene diterpenoid with potential applications against a number of viruses, including the mosquito-transmitted dengue virus (DENV). In this study, we evaluated the anti-viral activity of three 14-aryloxy analogues (ZAD-1 to ZAD-3) of andrographolide against Zika virus (ZIKV) and DENV. Interestingly, one analogue, ZAD-1, showed better activity against both ZIKV and DENV than the parental andrographolide. A two-dimension (2D) proteomic analysis of human A549 cells treated with ZAD-1 compared to cells treated with andrographolide identified four differentially expressed proteins (heat shock 70 kDa protein 1 (HSPA1A), phosphoglycerate kinase 1 (PGK1), transketolase (TKT) and GTP-binding nuclear protein Ran (Ran)). Western blot analysis confirmed that ZAD-1 treatment downregulated expression of HSPA1A and upregulated expression of PGK1 as compared to andrographolide treatment. These results suggest that 14-aryloxy analogues of andrographolide have the potential for further development as anti-DENV and anti-ZIKV agents.

Bioactive Natural Antivirals: An Updated Review of the Available Plants and Isolated Molecules

Viral infections and associated diseases are responsible for a substantial number of mortality and public health problems around the world. Each year, infectious diseases kill 3.5 million people worldwide. The current pandemic caused by COVID-19 has become the greatest health hazard to people in their lifetime. There are many antiviral drugs and vaccines available against viruses, but they have many disadvantages, too. There are numerous side effects for conventional drugs, and active mutation also creates drug resistance against various viruses. This has led scientists to search herbs as a source for the discovery of more efficient new antivirals. According to the World Health Organization (WHO), 65% of the world population is in the practice of using plants and herbs as part of treatment modality. Additionally, plants have an advantage in drug discovery based on their long-term use by humans, and a reduced toxicity and abundance of bioactive compounds can be expected as a result. In this review, we have highlighted the important viruses, their drug targets, and their replication cycle. We provide in-depth and insightful information about the most favorable plant extracts and their derived phytochemicals against viral targets. Our major conclusion is that plant extracts and their isolated pure compounds are essential sources for the current viral infections and useful for future challenges.

A systematic review on COVID-19 pandemic with special emphasis on curative potentials of Nigeria based medicinal plants

Despite the frightening mortality rate associated with COVID-19, there is no known approved drug to effectively combat the pandemic. COVID-19 clinical manifestations include fever, fatigue, cough, shortness of breath, and other complications. At present, there is no known effective treatment or vaccine that can mitigate/inhibit SARS-CoV-2. Available clinical intervention for COVID-19 is only palliative and limited to support. Thus, there is an exigent need for effective and non-invasive treatment. This article evaluates the possible mechanism of actions of SARS-CoV-2 and present Nigeria based medicinal plants which have pharmacological and biological activities that can mitigate the hallmarks of the pathogenesis of COVID-19. SARS-CoV-2 mode of actions includes hyper-inflammation characterized by a severe and fatal hyper-cytokinaemia with multi-organ failure; immunosuppression; reduction of angiotensin-converting enzyme 2 (ACE2) to enhance pulmonary vascular permeability causing damage to the alveoli; and further activated by open reading frame (ORF)3a, ORF3b, and ORF7a via c-Jun N- terminal kinase (JNK) pathway which induces lung damage. These mechanisms of action of SARS-CoV-2 can be mitigated by a combination therapy of medicinal herbs based on their pharmacological activities. Since the clinical manifestations of COVID-19 are multifactorial with co-morbidities, we strongly recommend the use of combined therapy such that two or more herbs with specific therapeutic actions are administered to combat the mediators of the disease.

Design, synthesis and discovery of andrographolide derivatives against Zika virus infection

The Zika endemic established by imported and local transmission is of significant concern and effective anti-ZIKV drugs remain an urgent unmet need. As andrographolide was identified to be an inhibitor of DENV and CHIKV and the importance of quinoline structure against infectious diseases was considered, we are interested in studying its andrographolide derivatives with quinoline moiety against Zika virus infection. In addition to screening eight in-house derivatives of andrographolide, sixteen new derivatives were designed, synthesized and tested against Zika virus infection. Among these compounds, two most potent anti-Zika compounds of 19-acetylated 14α-(5',7'-dichloro-8'-quinolyloxy) derivative 17b and 14β-(8'-quinolyloxy)-3,19- diol derivative 3 with the highest selectivity were discovered. The SAR analysis indicates that rational and optimal combined modification/s at 3-, 14-, or 19-positions can make derivatives less toxic and more potent against Zika infection, and both of 3 and 17b are suitable as leads for designing new generation of andrographolide derivatives with quinoline or its structure- and property-related moieties against Zika virus and other arboviruses.

Natural Products-Derived Chemicals: Breaking Barriers to Novel Anti-HSV Drug Development

Recently, the problem of viral infection, particularly the infection with herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2), has dramatically increased and caused a significant challenge to public health due to the rising problem of drug resistance. The antiherpetic drug resistance crisis has been attributed to the overuse of these medications, as well as the lack of new drug development by the pharmaceutical industry due to reduced economic inducements and challenging regulatory requirements. Therefore, the development of novel antiviral drugs against HSV infections would be a step forward in improving global combat against these infections. The incorporation of biologically active natural products into anti-HSV drug development at the clinical level has gained limited attention to date. Thus, the search for new drugs from natural products that could enter clinical practice with lessened resistance, less undesirable effects, and various mechanisms of action is greatly needed to break the barriers to novel antiherpetic drug development, which, in turn, will pave the road towards the efficient and safe treatment of HSV infections. In this review, we aim to provide an up-to-date overview of the recent advances in natural antiherpetic agents. Additionally, this paper covers a large scale of phenolic compounds, alkaloids, terpenoids, polysaccharides, peptides, and other miscellaneous compounds derived from various sources of natural origin (plants, marine organisms, microbial sources, lichen species, insects, and mushrooms) with promising activities against HSV infections; these are in vitro and in vivo studies. This work also highlights bioactive natural products that could be used as templates for the further development of anti-HSV drugs at both animal and clinical levels, along with the potential mechanisms by which these compounds induce anti-HSV properties. Future insights into the development of these molecules as safe and effective natural anti-HSV drugs are also debated.

Wound Healing and the Use of Medicinal Plants

Cutaneous wound healing is the process by which skin repairs itself. It is generally accepted that cutaneous wound healing can be divided into 4 phases: haemostasis, inflammation, proliferation, and remodelling. In humans, keratinocytes re-form a functional epidermis (reepithelialization) as rapidly as possible, closing the wound and reestablishing tissue homeostasis. Dermal fibroblasts migrate into the wound bed and proliferate, creating “granulation tissue” rich in extracellular matrix proteins and supporting the growth of new blood vessels. Ultimately, this is remodelled over an extended period, returning the injured tissue to a state similar to that before injury. Dysregulation in any phase of the wound healing cascade delays healing and may result in various skin pathologies, including nonhealing, or chronic ulceration. Indigenous and traditional medicines make extensive use of natural products and derivatives of natural products and provide more than half of all medicines consumed today throughout the world. Recognising the important role traditional medicine continues to play, we have undertaken an extensive survey of literature reporting the use of medical plants and plant-based products for cutaneous wounds. We describe the active ingredients, bioactivities, clinical uses, formulations, methods of preparation, and clinical value of 36 medical plant species. Several species stand out, including Centella asiatica, Curcuma longa, and Paeonia suffruticosa, which are popular wound healing products used by several cultures and ethnic groups. The popularity and evidence of continued use clearly indicates that there are still lessons to be learned from traditional practices. Hidden in the myriad of natural products and derivatives from natural products are undescribed reagents, unexplored combinations, and adjunct compounds that could have a place in the contemporary therapeutic inventory.

Treatment with andrographolide sulfonate provides additional benefits to imipenem in a mouse model of Klebsiella pneumoniae pneumonia

Klebsiella pneumoniae is a primary cause of community-acquired and nosocomial respiratory infections, and K. pneumoniae resistance to the current treatment approach with carbapenem is worsening. Andrographolide is a natural diterpenoid from Andrographis paniculata that was shown to exert anti-inflammatory activity. We herein show that pretreatment with a water-soluble andrographolide sulfonate significantly attenuate lung injury and infiltration of inflammatory cells. Interestingly, mice receiving combined treatment with andrographolide sulfonate displayed perfect survival rate than the mice treatment with imipenem alone, and monocyte chemotactic protein 5 (MCP-5) level was decreased further. These findings suggest that andrographolide sulfonate could as a potential synergist for antibiotic treatment of bacteria-induced inflammation.

Phytochemistry, Pharmacology and Clinical Use of Andrographis paniculata

Andrographis paniculata (Burma f.) Wall ex Nees (Acanthaceae) is a common weed distributed throughout the tropical and subtropical regions. All parts of A. paniculata are extremely bitter in taste. This plant is well known in Siddha, Ayurvedic and traditional (tribal) systems of medicine in India. A. paniculata is used for the treatment of infectious diseases, which account for the major proportion of health problems, and which are most often used in the traditional system of medicine. The major active components of the plant are andrographiloids, which have been extensively studied in a variety of models including human clinical trials for their therapeutic effects. Moreover, A. paniculata is known to have very low toxicity in animals and humans. The plant also exhibits antifertility effects. Most of the traditional uses of the species have some scientific basis. This review is an attempt to summarize the available information on A. paniculata for further investigation.

Novel Therapeutics for Epstein⁻Barr Virus

Epstein–Barr virus (EBV) is a human γ-herpesvirus that infects up to 95% of the adult population. Primary EBV infection usually occurs during childhood and is generally asymptomatic, though the virus can cause infectious mononucleosis in 35–50% of the cases when infection occurs later in life. EBV infects mainly B-cells and epithelial cells, establishing latency in resting memory B-cells and possibly also in epithelial cells. EBV is recognized as an oncogenic virus but in immunocompetent hosts, EBV reactivation is controlled by the immune response preventing transformation in vivo. Under immunosuppression, regardless of the cause, the immune system can lose control of EBV replication, which may result in the appearance of neoplasms. The primary malignancies related to EBV are B-cell lymphomas and nasopharyngeal carcinoma, which reflects the primary cell targets of viral infection in vivo. Although a number of antivirals were proven to inhibit EBV replication in vitro, they had limited success in the clinic and to date no antiviral drug has been approved for the treatment of EBV infections. We review here the antiviral drugs that have been evaluated in the clinic to treat EBV infections and discuss novel molecules with anti-EBV activity under investigation as well as new strategies to treat EBV-related diseases.