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

Composing functional food from agro-forest wastes: Selectively extracting bioactive compounds using supercritical fluid extraction

Supercritical fluid extraction (SFE) employing carbon dioxide (SC-CO2) is an efficient method to extract bioactive compounds from agro-forest wastes. These compounds maintain and/or improve food nutrition, safety, freshness, taste, and health and are employed as natural functional food components. To highlight the potential of this technology, we focus on the following current advances: (I) parameters affecting solubility in SFE (pressure, temperature, SC-CO2 flow rate, extraction time, and co-solvents); (II) extraction spectra and yield obtained according to proportion and composition of co-solvents; (III) extract bioactivity for functional food production. Fatty acids, monoterpenes, sesquiterpenes, diterpenoids, and low-polarity phenolic acids and triterpenoids were extracted using SFE without a co-solvent. High-polarity phenolic acids and flavonoids, tannins, carotenoids, and alkaloids were only extracted with the help of co-solvents. Using a co-solvent significantly improved the triterpenoid, flavonoid, and phenolic acid yield with a medium polarity.

Integrating Transcriptome and Chemical Analyses to Provide Insights into Biosynthesis of Terpenoids and Flavonoids in the Medicinal Industrial Crop Andrographis paniculate and Its Antiviral Medicinal Parts

Andrographis paniculata is a medicinal plant traditionally used to produce diterpene lactones and flavonoids, which possess various biological activities. Widely distributed in China, India, and other Southeast Asia countries, A. paniculata has become an important economic crop, significantly treating SARS-CoV-2, and is being cultivated on a large scale in southern China. The biosynthesis of active ingredients in A. paniculata are regulated and controlled by genes, but their specific roles are still not fully understood. To further explore the growth regulation factors and utilization of its medicinal parts of this industrial crop, chemical and transcriptome analyses were conducted on the roots, stems, and leaves of A. paniculata to identify the biosynthesis pathways and related candidate genes of the active ingredients. The chemical analysis revealed that the main components of A. paniculata were diterpene lactones and flavonoids, which displayed potential ability to treat SARS-CoV-2 through molecular docking. Moreover, the transcriptome sequencing annotated a total of 40,850 unigenes, including 7962 differentially expressed genes. Among these, 120 genes were involved in diterpene lactone biosynthesis and 60 genes were involved in flavonoid biosynthesis. The expression of diterpene lactone-related genes was the highest in leaves and the lowest in roots, consistent with our content determination results. It is speculated that these highly expressed genes in leaves may be involved in the biosynthesis pathway of diterpenes. Furthermore, two class Ⅰ terpene synthases in A. paniculata transcriptome were also annotated, providing reference for the downstream pathway of the diterpene lactone biosynthesis. With their excellent market value, our experiments will promote the study of the biosynthetic genes for active ingredients in A. paniculata and provide insights for subsequent in vitro biosynthesis.

Exploring the Therapeutic Potential of Traditional Antimalarial and Antidengue Plants: A Mechanistic Perspective

Malaria, a highly perilous infectious disease, impacted approximately 230 million individuals globally in 2019. Mosquitoes, vectors of over 10% of worldwide diseases, pose a significant public health menace. The pressing need for novel antimalarial drugs arises due to the imminent threat faced by nearly 40% of the global population and the escalating resistance of parasites to current treatments. This study comprehensively addresses prevalent parasitic and viral illnesses transmitted by mosquitoes, leading to the annual symptomatic infections of 400 million individuals, placing 100 million at constant risk of contracting these diseases. Extensive investigations underscore the pivotal role of traditional plants as rich sources for pioneering pharmaceuticals. The latter half of this century witnessed the ascent of bioactive compounds within traditional medicine, laying the foundation for modern therapeutic breakthroughs. Herbal medicine, notably influential in underdeveloped or developing nations, remains an essential healthcare resource. Traditional Indian medical systems such as Ayurveda, Siddha, and Unani, with a history of successful outcomes, highlight the potential of these methodologies. Current scrutiny of Indian medicinal herbs reveals their promise as cutting-edge drug reservoirs. The propensity of plant-derived compounds to interact with biological receptors positions them as prime candidates for drug development. Yet, a comprehensive perspective is crucial. While this study underscores the promise of plant-based compounds as therapeutic agents against malaria and dengue fever, acknowledging the intricate complexities of drug development and the challenges therein are imperative. The journey from traditional remedies to contemporary medical applications is multifaceted and warrants prudent consideration. This research aspires to offer invaluable insights into the management of malaria and dengue fever. By unveiling plant-based compounds with potential antimalarial and antiviral properties, this study aims to contribute to disease control. In pursuit of this goal, a thorough understanding of the mechanistic foundations of traditional antimalarial and antidengue plants opens doors to novel therapeutic avenues.

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.

Computational evaluation of quinones of Nigella sativa L. as potential inhibitor of dengue virus NS5 methyltransferase

Aedes aegypti is the primary vector for the transmission of the dengue virus, which causes dengue fever, dengue hemorrhagic illness and dengue shock syndrome. There is now no antiviral medication available to treat DENV, which kills thousands of people each year and infects millions of individuals. A possible target for the creation of fresh and efficient dengue treatments is the DENV-3 NS5 MTase. So, Nigella sativa quinones were examined using in silico methods to find natural anti-DENV compounds. The in silico docking was conducted utilising the Discovery Studio software on the quinones of N. sativa and the active site of the target protein DENV-3 NS5 MTase. In addition, the druggability and pharmacokinetics of the lead compound were assessed. Dithymoquinone was comparable to the reference compound in terms of its ability to bind to the active site of target protein. Dithymoquinone met the requirements for drug likeness and Lipinski's principles, as demonstrated by the ADMET analysis and drug likeness results. The current study indicated that the dithymoquinone from N. sativa had anti-DENV activity, suggesting further drug development and dengue treatment optimisation.Communicated by Ramaswamy H. Sarma.

Phaleria macrocarpa (Scheff.) Boerl.: An updated review of pharmacological effects, toxicity studies, and separation techniques

Phaleria macrocarpa (Scheff.) Boerl. is geographically distributed around Papua Island, Indonesia. Traditionally, P. macrocarpa is exercised to reduce pain, stomachache, diarrhea, tumor problems, blood glucose, cholesterol, and blood pressure. A growing interest in the medicinal values of P. macrocarpa especially in Asia reflects the usage of diverse extraction techniques, particularly modern approaches. In this review article, the extraction methods and solvents relevant to P. macrocarpa were discussed, with the extent of its pharmacological activities. Recent bibliographic databases such as Google Scholar, PubMed, and Elsevier between 2010 and 2022 were assessed. Based on the findings, the pharmacological studies of P. macrocarpa are still pertinent to its traditional uses but primarily emphasise anti-proliferative activity especially colon and breast cancer cells with low toxicity and fruit as the most studied plant part. The utilization of modern separation techniques has predominantly been aimed at extracting mangiferin and phenolic-rich compounds and evaluating their antioxidant capacity. However, the isolation of bioactive compounds remains a challenge, leading to the extensive utilization of the extracts in in vivo studies. This review endeavors to highlight modern extraction methods that could potentially be used as a point of reference in the future for exploring novel bioactive compounds and drug discovery on a multi-scale extraction level.

Monkeypox virus is nature's wake-up call: a bird's-eye view

Several infections have emerged in humans, domestic animals, wildlife, and plant populations, causing a severe problem for humanity. Since the discovery of the Monkeypox virus (Mpox) in 1958 in Copenhagen, Denmark, it has resurfaced several times, producing severe infections in humans and resulting in a significant fatality rate. Mpox is an Orthopoxvirus of the Poxviridae family. This family contains various medically important viruses. The natural reservoir of Mpox is unknown yet. Mpox might be carried by African rodents and nonhuman primates (such as monkeys). The role of monkeys has been confirmed by its various outbreaks. The infection may be transferred from unidentified wild animals to monkeys, who can then spread it to humans by crossing species barriers. In close contact, human-to-human transmission is also possible. Mpox outbreaks have been documented regularly in Central and Western Africa, but recently in 2022, it has spread to over one hundred-six countries. There is no specific treatment for it, although the smallpox vaccine, antivirals, and vaccinia immune globulin help in the effective management of Mpox. In conclusion: Monkeypox poses a severe threat to public health due to the lack of specific vaccinations and effective antivirals. Surveillance studies in affected regions can assist in the early diagnosis of disease and help to control significant outbreaks. The present review provides information on epidemiology, clinical symptoms, risk factors, diagnosis, and preventive measures of Mpox.

Perspectives on the current antiviral developments towards RNA-dependent RNA polymerase (RdRp) and methyltransferase (MTase) domains of dengue virus non-structural protein 5 (DENV-NS5)

Dengue virus (DENV) infection is one of the most emerging arboviral infections in humans. DENV is a positive-stranded RNA virus in the Flaviviridae family consisting of an 11 kb genome. DENV non-structural protein 5 (DENV-NS5) constitutes the largest among the non-structural proteins, which act as two domains, the RNA-dependent RNA polymerase (RdRp) and RNA methyltransferase enzyme (MTase). The DENV-NS5 RdRp domain contributes to the viral replication stages, whereas the MTase initiates viral RNA capping and facilitates polyprotein translation. Given the functions of both DENV-NS5 domains have made them an important druggable target. Possible therapeutic interventions and drug discoveries against DENV infection were thoroughly reviewed; however, a current update on the therapeutic strategies specific to DENV-NS5 or its active domains was not attempted. Since most potential compounds and drugs targeting the DENV-NS5 were evaluated in both in vitro cultures and animal models, a more detailed evaluation of molecules/drug candidates still requires investigation in randomized controlled clinical trials. This review summarizes current perspectives on the therapeutic strategies adopted to target the DENV-NS5 (RdRp and MTase domains) at the host-pathogen interface and further discusses the directions to identify candidate drugs to combat DENV infection.

Andrographolide exerts anti-respiratory syncytial virus activity by up-regulating heme oxygenase-1 independent of interferon responses in human airway epithelial cells

BACKGROUND

Respiratory syncytial virus (RSV) is the leading cause of mortality and morbidity in children under the age of five. Despite this, there is still a lack of safe and effective vaccines and antiviral agents for clinical use. Andrographolide exerts antiviral functions against a variety of viruses, but whether (and how) it exerts antiviral effects on RSV remains unclear.

METHODS AND RESULTS

In vitro RSV infection models using A549 and 16HBE cell lines were established, and the effects of andrographolide on RSV were analyzed via RSV N gene load and proinflammatory cytokine levels. The RNA transcriptome was sequenced, and data were analyzed by R software. Andrographolide-related target genes were extracted via network pharmacology using online databases. Lentiviral transfection was applied to knockdown the heme oxygenase-1 gene (Hmox1, HO-1). Results showed that andrographolide suppressed RSV replication and attenuated subsequent inflammation. Network pharmacology and RNA sequencing analysis indicated that the hub gene HO-1 may play a pivotal role in the anti-RSV effects of andrographolide. Furthermore, andrographolide exerted antiviral effects against RSV partially by inducing HO-1 but did not activate the antiviral interferon response.

CONCLUSION

Our findings demonstrated that andrographolide exerted anti-RSV activity by up-regulating HO-1 expression in human airway epithelial cells, providing novel insights into potential therapeutic targets and drug repurposing in RSV infection.

Evaluations of Andrographolide-Rich Fractions of Andrographis paniculata with Enhanced Potential Antioxidant, Anticancer, Antihypertensive, and Anti-Inflammatory Activities

Andrographis paniculata is widely used as a traditional medicine in Asian countries. It has been classified as a safe and non-toxic medicine by traditional Chinese medicine. The investigation of the biological activities of A. paniculata is still focused on the crude extract and isolation of its main active compound, andrographolide, and its derivatives. However, the use of andrographolide alone has been shown to exacerbate unwanted effects. This highlights the importance of developing a fraction of A. paniculata with enhanced efficacy as an herbal-based medicine. In this study, the extraction and fractionation of A. paniculata, followed by quantitative analysis using high-performance liquid chromatography coupled with a DAD detector, were established to quantify the andrographolide and its derivative in each fraction. Biological activities, such as antioxidant, anticancer, antihypertensive, and anti-inflammatory activities, were evaluated to study their correlations with the quantification of active substances of A. paniculata extract and its fractions. The 50% methanolic fraction of A. paniculata exhibited the best cytotoxic activities against CACO-2 cells, as well as the best anti-inflammatory and antihypertensive activities compared to other extracts. The 50% methanolic fraction also displayed the highest quantification of its main active compound, andrographolide, and its derivatives, 14-deoxy-11,12-didehydroandrographolide, neoandrographolide, and andrograpanin, among others.

The Current Landscape of Bioactive Molecules against DENV: A Systematic Review

With a 30-fold increase in incidence over the previous 50 years, dengue fever is now the most widespread viral disease transmitted by mosquitoes in the world. The intricate interaction of the human defense system, hereditary predisposition, and specific bitterness elements is more likely to be the pathogenesis of dengue. There are presently no viable treatments for dengue. Synthetic drugs which are used against this ailment also show major side effects. There must be a deeper understanding of the underlying mechanism generating severe symptoms to develop auguring markers, cutting-edge diagnostics, and treatments and finally a well-rounded and secure antiserum. Hence, the aim is to search for safer and more potent drugs derived from plants. Plants or herbs are mainly targeting replication or its enzyme or specific stereotypes, though an exact mechanism of phytoconstituents interfering with the viral replication is still undiscovered. The present attempt provided the update with the objective to bringing up forward pathophysiological eventualities involved in dengue virus along with the naturally derived treatment relevant to provide the impregnable therapy by evading the noxious symptoms for dengue fever. Governor's plum, Cryptocarya chartacea, magnolia berry, and Chinese ginger are such plants exhibiting many effective phytoconstituents against DENV and can be further explored for novel drug discovery by medicinal scientists.

A randomized controlled pilot study of add-on therapy of CIM-MEG19 (standardized Andrographis paniculata formulation) in mild to moderate COVID-19

BACKGROUND

Traditional knowledge and scientific shreds of evidence strongly support the repurpose of Kalmegh (Andrographis paniculata, CIM-MEG19) as an alternate therapy for prophylactic management and treatment of severe acute respiratory syndrome coronavirus (SARS-CoV) and associated health disorders.

PURPOSE

The study aimed to assess the efficacy and safety of the CIM-MEG19 (standardized A. paniculata extract formulation), a proprietary Ayurvedic medicine in the COVID-19 management, clinical recovery, and outcomes in terms of hospitalization days as well as any sign of severity due to drug-drug interaction between CIM-MEG19 ^TM and standard of care (SoC).

METHODS

A randomized, parallel-group, active-controlled interventional pilot clinical study was conducted. The Group-A subjects were assigned to CIM-MEG19 add-on to SoC treatment using modern medicine without antiviral drug whereas Group-B patients with SoC treatment using modern medicine and recommended antiviral drug for COVID-19 management. Eighty RTPCR (real-time polymerase chain reaction) positive and eligible COVID-19 patients of age >18 years, having mild or moderate severity, were enrolled.

RESULTS

Clinical improvement in reduction of symptoms showed significant (p<0.0001) results in the average days in subjects of group-A (Investigational intervention arm) compared to Group B (SoC). The RT-PCR investigation exhibited COVID negative for 50 % in CIM-MEG19 add-on and 47% in SoC treatment after 8-11 days. Similarly, biochemical investigations showed that CIM-MEG19 group-A had a significant (p ≤ 0.05) effect on C-Reactive Protein (CRP) and Interleukin-6 (IL-6) after 14 days of treatment. Additionally, improvement in D-Dimer, ESR, and LDH in CIM-MEG19 add-on therapy was also observed.

CONCLUSIONS

The study demonstrated an excellent safety profile, declining the severity of the infection and halting the disease advancement/progression. CIM-Meg19 might be used as a potential natural drug for treating COVID-19.

Natural Compounds as Non-Nucleoside Inhibitors of Zika Virus Polymerase through Integration of In Silico and In Vitro Approaches

Although the past epidemic of Zika virus (ZIKV) resulted in severe neurological consequences for infected infants and adults, there are still no approved drugs to treat ZIKV infection. In this study, we applied computational approaches to screen an in-house database of 77 natural and semi-synthetic compounds against ZIKV NS5 RNA-dependent RNA-polymerase (NS5 RdRp), an essential protein for viral RNA elongation during the replication process. For this purpose, we integrated computational approaches such as binding-site conservation, chemical space analysis and molecular docking. As a result, we prioritized nine virtual hits for experimental evaluation. Enzymatic assays confirmed that pedalitin and quercetin inhibited ZIKV NS5 RdRp with IC₅₀ values of 4.1 and 0.5 µM, respectively. Moreover, pedalitin also displayed antiviral activity on ZIKV infection with an EC₅₀ of 19.28 µM cell-based assays, with low toxicity in Vero cells (CC₅₀ = 83.66 µM) and selectivity index of 4.34. These results demonstrate the potential of the natural compounds pedalitin and quercetin as candidates for structural optimization studies towards the discovery of new anti-ZIKV drug candidates.

Zika virus as an emerging arbovirus of international public health concern

Zika virus (ZIKV) was identified in 1947 in a rhesus monkey during an investigation of the yellow fever virus in the Zika Forest of Uganda; it was also isolated later from humans in Nigeria. The main distribution areas of ZIKV were the African mainland and South-East Asia in the 1980s, Micronesia in 2007, and more recently the Americas in 2014. ZIKV belongs to the Flaviviridae family and Flavivirus genus. ZIKV infection, which is transmitted by Aedes mosquitoes, is an emerging arbovirus disease. The clinical symptoms of ZIKV infection are fever, headache, rashes, arthralgia, and conjunctivitis, which clinically resemble dengue fever syndrome. Sometimes, ZIKV infection has been associated with Guillain-Barré syndrome and microcephaly. At the end of 2015, following an increase in cases of ZIKV infection associated with Guillain-Barré syndrome and microcephaly in newborns in Brazil, the World Health Organization declared a global emergency. Therefore, considering the global distribution and pathogenic nature of this virus, the current study aimed at reviewing the virologic features, transmission patterns, clinical manifestations, diagnosis, treatment, and prevention of ZIKV infection.

Dimethylaminoethyl Methacrylate/Diethylene Glycol Dimethacrylate Grafted onto Folate-Esterified Bagasse Xylan/Andrographolide Composite Nanoderivative: Synthesis, Molecular Docking and Biological Activity

As a biocompatible biomaterial, bagasse xylan (BX) has been widely used in the biomedical field. The low biological activity of andrographolide (AD) restricts its development, so AD with certain anticancer activity is introduced. We use chemical modification methods such as grafting and esterification to improve the biological activity and make a novel anticancer nanomaterial. On the basis of the esterification of a mixture of BX and AD with folic acid (FA), a novel anticancer nanoderivative of bagasse xylan/andrographolide folate-g-dimethylaminoethyl methacrylate (DMAEMA)/diethylene glycol dimethacrylate (DEGDMA) nanoparticles (FA-BX/AD-g-DMAEMA/DEGDMA NPs) was synthesized by introducing DMAEMA and DEGDMA monomers through a graft copolymerization and nanoprecipitation method. The effects of reaction temperature, reaction time, the initiator concentration and the mass ratio of FA-BX/AD to mixed monomers on the grafting rate (GR) were investigated. The structure of the obtained product was characterized by FTIR, SEM, XRD and DTG. Further, molecular docking and MTT assays were performed to understand the possible docking sites with the target proteins and the anticancer activity of the product. The results showed that the GR of the obtained product was 79% under the conditions of the initiator concentration 55 mmol/L, m (FA-BX/AD):m (mixed monomer) = 1:2, reaction temperature 50 °C and reaction time 5 h. The inhibition rate of FA-BX/AD-g-DMAEMA/DEGDMA NPs on human lung cancer cells (NCI-H460) can reach 39.77 ± 5.62%, which is about 7.6 times higher than that of BX. Therefore, this material may have potential applications in the development of anticancer drug or carriers and functional materials.

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.

Traditional Knowledge to Contemporary Medication in the Treatment of Infectious Disease Dengue: A Review

Dengue has become a worldwide affliction despite incessant efforts to search for a cure for this long-lived disease. Optimistic consequences for dengue vaccine are implausible as the efficiency is tied to previous dengue virus (DENV) exposure and a very high cost is required for large-scale production of vaccine. Medicinal plants are idyllic substitutes to fight DENV infection since they constitute important components of traditional medicine and show antiviral properties, although the mechanism behind the action of bioactive compounds to obstruct viral replication is less explored and yet to be discovered. This review includes the existing traditional knowledge on how DENV infects and multiplies in the host cells, conscripting different medicinal plants that obtained bioactive compounds with anti-dengue properties, and the probable mechanism on how bioactive compounds modulate the host immune system during DENV infection. Moreover, different plant species having such bioactive compounds reported for anti-DENV efficiency should be validated scientifically via different in vitro and in vivo studies.

A New Source of Diterpene Lactones From Andrographis paniculata (Burm. f.) Nees—Two Endophytic Fungi of Colletotrichum sp. With Antibacterial and Antioxidant Activities

Endophytic fungi of medicinal plants are abundant, and their metabolites often have antioxidant, antibacterial, and antitumor effects and can produce secondary metabolites identical or similar to those of their hosts, which can mitigate the problem of insufficient supply of medicinal plants. In this study, we screened endophytic fungi for strains that produce the same diterpene lactones as Andrographis paniculata based on their biological activity. Firstly, the dominant group of endophytic fungi of Andrographis paniculata was screened and pathogenicity was studied using Koch’s rule. Secondly, DPPH, ABTS, OH, PTIO radical scavenging, and FRAP assays were used to detect the antioxidant activity of the extracellular extracts of the strains, and total phenol and total flavonoid contents of the strains with high antioxidant capacity were determined. S. aureus, B. subtilis, E. coli, and P. aeruginosa were used to determine the antibacterial activity of the mycelial extracts of the strains. Finally, the secondary metabolites of the mycelial extracts of the strains were examined by high-performance liquid chromatography. The results showed that 32 strains of Andrographis paniculata were relatively isolated > 70% and non-pathogenic. Extracellular extracts of strains AP-1 and AP-4 showed vigorous antioxidant activity, and AP-4, AP-12, AP-47, and AP-48 showed antibacterial activity against four strains of bacteria. The HPLC results indicated that the mycelial extracts of AP-4 and AP-12 contained diterpene lactones. The two endophytic fungi were recognized as Colletotrichum sp. The study successfully obtained diterpene lactones from the endophytic fungus of Andrographis paniculata and confirmed the feasibility of using endophytic fungal strains to produce active substances consistent with the host. It was also useful for exploring endophytic fungi and medicinal plants. The relationship provides theoretical guidance.

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.

An insight into the pharmacological and analytical potential of Andrographolide

Andrographis paniculata is an annual medicinal herb from the family Acanthaceae. Andrographolide is generally considered an essential bioactive component of plant A. paniculata. Since ancient times, it has been widely recognized for its therapeutic qualities and has attracted the scientific and medical communities' attention. This review summarizes the molecular, clinical, and in vitro research of compound andrographolide and its mechanism of action. Andrographolide, when combined with other enhancing agents, offers a wide variety of health benefits. The therapeutic potential of andrographolide has been exemplified and exhibited by directly regulating genes and indirectly interacting with small molecules and different enzymes. This review compiles and consolidates the pharmacological action of andrographolide and its analogs and deciphers the gaps that have hindered its use in medicinal research.

Andrographolide: A Herbal-Chemosynthetic Approach for Enhancing Immunity, Combating Viral Infections, and Its Implication on Human Health

Plants consistently synthesize and accumulate medically valuable secondary metabolites which can be isolated and clinically tested under in vitro conditions. An advancement with such important phytochemical production has been recognized and utilized as herbal drugs. Bioactive andrographolide (AGL; C20H30O5) isolated from Andrographis paniculate (AP) (Kalmegh) is a diterpenoid lactones having multifunctional medicinal properties including anti-manic, anti-inflammatory, liver, and lung protective. AGL is known for its immunostimulant activity against a variety of microbial infections thereby, regulating classical and alternative macrophage activation, Ag-specific antibody production during immune disorder therapy. In vitro studies with AGL found it to be effective against multiple tumors, neuronal disorders, diabetes, pneumonia, fibrosis, and other diverse therapeutic misadventures. Generally, virus-based diseases like ZIKA, influenza A virus subtype (H1NI), Ebola (EBOV), Dengue (DENV), and coronavirus (COVID-19) epidemics have greatly increased scientific interest and demands to develop more effective and economical immunomodulating drugs with minimal side effects. Trials and in vitro pharmacological studies with AGL and medicinally beneficial herbs might contribute to benefit the human population without using chemical-based synthetic drugs. In this review, we have discussed the possible role of AGL as a promising herbal-chemo remedy during human diseases, viral infections and as an immunity booster.

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.

The Cat Que Virus: a resurfacing orthobunyavirus could lead to epidemics

The newly emerging and re-emerging of viral contagion in the present scenario are of more extensive health concern. After a long calm of many years, an unexpected eruption of the Cat Que Virus in China is a source of our concern. Cat Que Virus is an Arbovirus and belongs to the Simbu serogroup of the Orthobunyavirus genus of the Bunyaviridae family. The Simbu serogroup is an extremely diverse group of Arbovirus. The arboviruses are causing the infection in multiple hosts including humans and various livestock. They can cause mild to life-threatening infections. Arboviruses expand their spectrum and are more observable in recent times. Human actions have the most significant geophysical impact on the environment. Changes in rainfall patterns, floods, and the risk of extreme weather events are all consequences of climate change. These events may be connected to the extension of permissive vectors, geographic ranges, and therefore provide more chance of growth and spread of potential vector. Arboviruses are responsible for the health hazard to millions of people globally. It is critical to concentrate research and surveillance on these emerging and re-emerging viruses, particularly arthropod-borne viral infections. The appropriate research and surveillance on them will help us for the development of effective control and treatment strategies and also reduce health problems. The present review summarizes the current broad outline of discovery, evolution and dispersal of this unknown virus.

Ayurveda Rasayana as antivirals and immunomodulators: potential applications in COVID-19

Coronavirus disease (COVID-19) has been declared as a pandemic by the World Health Organization with rapid spread across 216 countries. COVID-19 pandemic has left its imprints on various health systems globally and caused immense social and economic disruptions. The scientific community across the globe is in a quest for digging the effective treatment for COVID-19 and exploring potential leads from traditional systems of healthcare across the world too. Ayurveda (Indian traditional system of medicine) has a comprehensive aspect of immunity through Rasayana which is a rejuvenation therapy. Here we attempt to generate the potential leads based on the classical text from Ayurveda in general and Rasayana in particular to develop effective antiviral and/or immunomodulator for potential or adjunct therapy in SARS-CoV-2. The Rasayana acts not only by resisting body to restrain or withstand the strength, severity or progression of a disease but also by promoting power of the body to prevent the manifestation of a disease. These Rasayana herbs are common in practice as immunomodulator, antiviral and protectives. The studies on Rasayana can provide an insight into the future course of research for the plausible development of effective management of COVID-19 by the utilization and development of various traditional systems of healthcare. Keeping in view the current pandemic situation, there is an urgent need of developing potential medicines. This study proposes certain prominent medicinal plants which may be further studied for drug development process and also in clinical setup under repurposing of these herbs.

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.

Andrographolide - A prospective remedy for chikungunya fever and viral arthritis

AIM

Andrographolide, the major bioactive compound of the plant Andrographis paniculata, exerts anti-inflammatory, cyto-, neuro- and hepato-protective effects. Traditional remedies for infectious diseases include A. paniculata for maladies like fever, pain, rashes which are associated with chikungunya and other arboviral diseases. Since andrographolide and A. paniculata have potent antiviral properties, the present review aims to provide a comprehensive report of symptoms and immunological molecules involved in chikungunya virus (CHIKV) infection and the therapeutic role of andrographolide in the mitigation of chikungunya and associated symptoms.

MATERIALS AND METHODS

Studies on the therapeutic role of A. paniculata and andrographolide in chikungunya and other viral infections published between 1991 and 2021 were searched on various databases.

RESULTS AND DISCUSSION

The havoc created by chikungunya is due to the associated debilitating symptoms including arthralgia and myalgia which sometimes remains for years. The authors reviewed and summarized the various symptoms and immunological molecules related to CHIKV replication and associated inflammation, oxidative and unfolded protein stress, apoptosis and arthritis. Additionally, the authors suggested andrographolide as a remedy for chikungunya and other arboviral infections by highlighting its role in the regulation of molecules involved in unfolded protein response pathway, immunomodulation, inflammation, virus multiplication, oxidative stress, apoptosis and arthritis.

CONCLUSION

The present review demonstrated the major complications associated with chikungunya and the role of andrographolide in alleviating the chikungunya associated symptoms to encourage further investigations using this promising compound towards early development of an anti-CHIKV drug. Chemical Compound studied: andrographolide (PubChem CID: 5318517).

Insights on Dengue and Zika NS5 RNA-dependent RNA polymerase (RdRp) inhibitors

Over recent years, many outbreaks caused by (re)emerging RNA viruses have been reported worldwide, including life-threatening Flaviviruses, such as Dengue (DENV) and Zika (ZIKV). Currently, there is only one licensed vaccine against Dengue, Dengvaxia®. However, its administration is not recommended for children under nine years. Still, there are no specific inhibitors available to treat these infectious diseases. Among the flaviviral proteins, NS5 RNA-dependent RNA polymerase (RdRp) is a metalloenzyme essential for viral replication, suggesting that it is a promising macromolecular target since it has no human homolog. Nowadays, several NS5 RdRp inhibitors have been reported, while none inhibitors are currently in clinical development. In this context, this review constitutes a comprehensive work focused on RdRp inhibitors from natural, synthetic, and even repurposing sources. Furthermore, their main aspects associated with the structure-activity relationship (SAR), proposed mechanisms of action, computational studies, and other topics will be discussed in detail.

Andrographis paniculata (Burm. F.) Wall. Ex Nees, Andrographolide, and Andrographolide Analogues as SARS-CoV-2 Antivirals? A Rapid Review

Drug repurposing is commonly employed in the search for potential therapeutic agents. Andrographis paniculata, a medicinal plant commonly used for symptomatic relief of the common cold, and its phytoconstituent andrographolide, have been repeatedly identified as potential antivirals against SARS-CoV-2. In light of new evidence emerging since the onset of the COVID-19 pandemic, this rapid review was conducted to identify and evaluate the current SARS-CoV-2 antiviral evidence for A. paniculata, andrographolide, and andrographolide analogs. A systematic search and screen strategy of electronic databases and gray literature was undertaken to identify relevant primary articles. One target-based in vitro study reported the 3CLpro inhibitory activity of andrographolide as being no better than disulfiram. Another Vero cell-based study reported potential SARS-CoV-2 inhibitory activity for both andrographolide and A. paniculata extract. Eleven in silico studies predicted the binding of andrographolide and its analogs to several key antiviral targets of SARS-CoV-2 including the spike protein-ACE-2 receptor complex, spike protein, ACE-2 receptor, RdRp, 3CLpro, PLpro, and N-protein RNA-binding domain. In conclusion, in silico and in vitro studies collectively suggest multi-pathway targeting SARS-CoV-2 antiviral properties of andrographolide and its analogs, but in vivo data are needed to support these predictions.

In-vitro and in-silico evaluation of the anti-chikungunya potential of Psidium guajava leaf extract and their synthesized silver nanoparticles

Chikungunya is a notorious viral infection, which affects a large segment of world populations in absence of vaccines and antivirals. The current study evaluates of anti-chikungunya activities of Psidium guajava leaves extract and their green synthesized silver nanoparticles. Green synthesized nanoparticles were well characterized for their size and stability by dynamic light scattering (DLS), zeta potential, scanning electron microscopy (SEM) and their functional groups were analyzed by FTIR. Maximum non-toxic doses (MNTD) of extracts and nanoparticles were analysed by using Vero cell-lines. Anti-chikungunya activities of extracts and nano-particles were determined on Vero cells and their effects on cell viability were measured by MTT assay. The P. guajava nano-particles and extracts revealed the anti-chikungunya activities in the Vero cell. The cells viability was increased by 40% and 60% as compared to the virus control, when these cells were treated with MNTD of P. guajava nano-particles and extracts, respectively. To know the reason for antiviral activity, molecular docking of phytochemicals was done against a replication essential cysteine protease (nsP2) of Chikungunya. It was found that phytochemicals; Longifollen and Quercetin showed the minimum binding energy with nsP2. P. guajava extracts can be exploited to develop an effective anti-chikungunya agent. In the absence of CHIKV vaccines and antivirals, P. guajava may be used to develop rapid, responsive, specific, and cost-effective anti-chikungunya agents.

A Bibliometric Analysis and Review of Supercritical Fluids for the Synthesis of Nanomaterials

Since the 1990s, supercritical fluids for the synthesis of nanomaterials have been paid more and more attention by researchers and have gradually become one of the most important ways to prepare nanomaterials. In this study, literature data on "supercritical fluids for the synthesis of nanomaterials" from 1998 to 2020 were obtained from the Web of Science database, and the data were processed and analyzed by the bibliometric method combined with Microsoft office 2019, Origin 2018, VOSviewer, and other software, so as to obtain the research status and development trend of "supercritical fluids for the synthesis of nanomaterials". The results show that since literature on "supercritical fluids for the synthesis of nanomaterials" appeared for the first time in 1998, the number of articles published every year has risen. In terms of this field, China has become the second-largest publishing country after the United States, and China and the United States display a lot of cooperation and exchanges in this field. "Supercritical CO2", "supercritical water", "supercritical antisolvent", "surface modification", and so on have become the research hotspots of "supercritical fluids for the synthesis of nanomaterials".