Antiviral activity of an aqueous extract derived from Aloe arborescens Mill. against a broad panel of viruses causing infections of the upper respiratory tract

New opportunities and perspectives on biosynthesis and bioactivities of secondary metabolites from Aloe vera

Historically, the genus Aloe has been an indispensable part of both traditional and modern medicine. Decades of intensive research have unveiled the major bioactive secondary metabolites of this plant. Recent pandemic outbreaks have revitalized curiosity in aloe metabolites, as they have proven pharmacokinetic profiles and repurposable chemical space. However, the structural complexity of these metabolites has hindered scientific advances in the chemical synthesis of these compounds. Multi-omics research interventions have transformed aloe research by providing insights into the biosynthesis of many of these compounds, for example, aloesone, aloenin, noreugenin, aloin, saponins, and carotenoids. Here, we summarize the biological activities of major aloe secondary metabolites with a focus on their mechanism of action. We also highlight the recent advances in decoding the aloe metabolite biosynthetic pathways and enzymatic machinery linked with these pathways. Proof-of-concept studies on in vitro, whole-cell, and microbial synthesis of aloe compounds have also been briefed. Research initiatives on the structural modification of various aloe metabolites to expand their chemical space and activity are detailed. Further, the technological limitations, patent status, and prospects of aloe secondary metabolites in biomedicine have been discussed.

Chemical structures, biological activities, and medicinal potentials of amine compounds detected from Aloe species

Unrestricted interest in Aloe species has grown rapidly, and a lot of research is currently being done to learn more about the properties of the various Aloe constituents. Organic compounds containing amine as functional group are present in a vivid variety of compounds, namely, amino acids, hormones, neurotransmitters, DNA, alkaloids, dyes, etc. These compounds have amine functional groups that have various biological activities, which make them responsible for medicinal potential in the form of pharmaceutical, nutraceutical, and cosmeceutical applications. Consequently, the present review work provides an indication of the amines investigated in Aloe species and their therapeutic uses. Various amine compounds of the Aloe species have effective biological properties to treat diseases. Generally, the genus Aloe has various active amine-containing compounds to combat diseases when humans use them in various forms.

Iranian Traditional Medicine (ITM) and Natural Remedies for Treatment of the Common Cold and Flu

Traditional Iranian medicine is usually used for both prevention and relief of cold and flu symptoms in China, Iran, and many other Asian countries all over the world. There are 4 kinds of influenza viruses. Unlike type B, which may cause seasonal epidemics, type A viruses can cause pandemics, and influenza C may lead to mild human infection with little public health effects. A literature review was done by using multiple databases such as ISI Web of knowledge, PubMed, Science Direct and Google Scholar. The most notable antiviral medicinal plants for flu and cold are honeysuckle flowers, thyme leaf, green chiretta, andrographis, peppermint oil and leaf and calendula. The most important expectorant medicinal plants for cold and flu are snake root, tulsi, licorice root, slippery elm, clove, and sage leaf. Recommended immunostimulant medicinal plants for cold and flu are eucalyptus, Echinacea root, ginseng, garlic, slippery elm, marshmallow, Usnea lichen, Isatis root, ginger root, and myrrh resin. Iranian traditional medicine, which is one of the oldest schools of traditional medicine, is one of the main concepts of disease and health, and it can be considered as an important complementary and alternative medicine, as in some cases, modern medicine has many side effects, low efficiency, and high costs. Medicinal plants and herbs, which are included in many traditional systems, have significant and promising bioactive components in organic life.

Microbiota-derived short chain fatty acids in fermented Kidachi Aloe promote antimicrobial, anticancer, and immunomodulatory activities

BACKGROUND

Fermented Aloe leaf juice is a commonly used food supplement in Japan. In a previous study, fermentation of A. arborescence juice was performed and the presence of short-chain fatty acids (SCFAs) was confirmed and quantified. Samples were collected before and after the fermentation process to be subjected, in the present study, to DNA extraction, 16S rRNA gene (V3-V4 regions) amplification, and sequencing by the next-generation Illumina MiSeq sequencer. Our work aims to analyze the sequences to assess the bacterial diversity in the juice before and after fermentation, identify the beneficial microbes responsible for the production of SCFAs, and evaluate some of the biological activities of the fermented juice.

RESULTS

Data revealed the richness and diversity of the bacterial community in the fermented juice compared to the unfermented control. Relative abundance of bacterial phyla showed that the majority of the microbial community in the test samples corresponded to Pseudomonadota (unfermented; 10.4%, fermented; 76.36%), followed by Bacillota (unfermented; 4.71%, fermented; 17.13%) and then Bacteroidota (unfermented; 0.57%, fermented; 1.64%). For the fermented sample, 84% of Bacillota were lactobacilli. A hierarchically clustered heatmap revealed that Lactobacillus was the most abundant genus in both samples suggesting its involvement in the production of SCFAs. To assess potential health benefits, the anticancer efficacy of the fermented product of A. arborescens was investigated against colorectal cancer (IC50 = 3.5 µg/ml) and liver cancer (IC50 = 6.367 µg/ml) compared to the normal peripheral blood mononuclear cells (PBMCs). Flow cytometric analysis of the cell cycle pattern revealed remarkable population arrest in G0 and G1, however, the highest percentages were mainly in the G1 phase for Hep-G2 (40.1%) and HCT-116 (53.2%) cell lines. This effect was accompanied by early apoptotic profiles of HCT-116 (36.9%) and late apoptosis for Hep-G2 (17.3%). Furthermore, immunomodulatory properties demonstrated a significantly (p < 0.001) reduced percentage of induced TNF-α while enhancing IFN-γ dramatically. For antimicrobial activities, marked broad-spectrum activities were recorded against some bacterial and fungal pathogens (17-37 mm inhibition zone diameter range).

CONCLUSION

Therefore, this study affords the basis of bacterial community composition in fermented A. arborescens juice as well as its potential biological benefits.

Broad-Spectrum Antivirals Derived from Natural Products

Scientific advances have led to the development and production of numerous vaccines and antiviral drugs, but viruses, including re-emerging and emerging viruses, such as SARS-CoV-2, remain a major threat to human health. Many antiviral agents are rarely used in clinical treatment, however, because of their inefficacy and resistance. The toxicity of natural products may be lower, and some natural products have multiple targets, which means less resistance. Therefore, natural products may be an effective means to solve virus infection in the future. New techniques and ideas are currently being developed for the design and screening of antiviral drugs thanks to recent revelations about virus replication mechanisms and the advancement of molecular docking technology. This review will summarize recently discovered antiviral drugs, mechanisms of action, and screening and design strategies for novel antiviral agents.

Natural Products for the Prevention and Treatment of Common Cold and Viral Respiratory Infections

The common cold is generally considered a usually harmless infectious disease of the upper respiratory pathway, with mostly mild symptoms. However, it should not be overlooked, as a severe cold can lead to serious complications, resulting in hospitalization or death in vulnerable patients. The treatment of the common cold remains purely symptomatic. Analgesics as well as oral antihistamines or decongestants may be advised to relieve fever, and local treatments can clear the airways and relieve nasal congestion, rhinorrhea, or sneezing. Certain medicinal plant specialties can be used as therapy or as complementary self-treatment. Recent scientific advances discussed in more detail in this review have demonstrated the plant's efficiency in the treatment of the common cold. This review presents an overview of plants used worldwide in the treatment of cold diseases.

EFFICACY AND SAFETY OF CANDELABRA ALOE EXTRACT (ALOE ARBORESCENS MILL.) IN PREVENTION AND TREATMENT OF UPPER RESPIRATORY TRACT INFECTIONS OF VARIOUS AETIOLOGIES

OBJECTIVE

The aim: To evaluate therapeutic effects of a product containing Aloe arborescens extract (AA) as the active substance in children aged 3-18 years with a diagnosed viral or bacterial upper respiratory tract infection and to assess their carers' satisfaction with the use of the product. The above-mentioned product is also indicated to control the loss of appetite. Thus, the study also assessed the effect of AA on this parameter.

PATIENTS AND METHODS

Materials and methods: A total of 6764 patients (children aged 3-18 years) were included in the study, which was conducted by 279 paediatrics and family medicine specialists (or being in the course of specialisation) from 237 centres. The efficacy was evaluated of the basis of reduction of upper respiratory tract infections (URIs) symptoms between the first and second visits with the application of the chi-square test.

RESULTS

Results: The most common primary diagnoses for which AA was used were common colds and recurrent acute URIs of viral aetiology. Symptoms reduction or resolution were reported in over: 81% of children with sore throat and/or hoarseness, 72% of children with earache, 64% of children with nasal discharge and/or the feeling of congested nose, 63% of children with cough, 89% of children with fever and 82% of children with sleep disturbances. Improvement in appetite was achieved in more than 66% of children. Almost 60% of the paediatric patients or their carers included in the study group were very satisfied with the efficacy of AA. More than 66% of carers were very satisfied with the dosing regimen and the vast majority of them (99%) would recommend the preparation to others. Two children demonstrated adverse effects (diarrhoea, abdominal pain) that were induced by application of the studied product. They resolved after its discontinuation.

CONCLUSION

Conclusions: AA applied in treatment of URIs in children highly effectively reduces symptoms of the diseases. Paediatric patients and their carers are satisfied with therapeutic effects of the syrup with regards to its all indications.

Emodin from Aloe inhibits Swine acute diarrhea syndrome coronavirus in cell culture

Swine acute diarrhea syndrome coronavirus (SADS-CoV) is an emerging swine enteropathogenic coronavirus that causes severe diarrhea in neonatal piglets, leading to serious economic losses to the pig industries. At present, there are no effective control measures for SADS, making an urgent need to exploit effective antiviral therapies. Here, we confirmed that Aloe extract (Ae) can strongly inhibit SADS-CoV in Vero and IPI-FX cells in vitro. Furthermore, we detected that Emodin from Ae had anti-SADS-CoV activity in cells but did not impair SADS-CoV infectivity directly. The time-of-addition assay showed that Emodin inhibits SADS-CoV infection at the whole stages of the viral replication cycle. Notably, we found that Emodin can significantly reduce virus particles attaching to the cell surface and induce TLR3 (p < 0.001), IFN-λ3 (p < 0.01), and ISG15 (p < 0.01) expressions in IPI-FX cells, indicating that the anti-SADS-CoV activity of Emodin might be due to blocking viral attachment and the activation of TLR3-IFN-λ3-ISG15 signaling axis. These results suggest that Emodin has the potential value for the development of anti-SADS-CoV drugs.

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

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

Utilization of Aloe Compounds in Combatting Viral Diseases

Plants contain underutilized resources of compounds that can be employed to combat viral diseases. Aloe vera (L.) Burm. f. (syn. Aloe barbadensis Mill.) has a long history of use in traditional medicine, and A. vera extracts have been reported to possess a huge breadth of pharmacological activities. Here, we discuss the potential of A. vera compounds as antivirals and immunomodulators for the treatment of viral diseases. In particular, we highlight the use of aloe emodin and acemannan as lead compounds that should be considered for further development in the management and prevention of viral diseases. Given the immunomodulatory capacity of A. vera compounds, especially those found in Aloe gel, we also put forward the idea that these compounds should be considered as adjuvants for viral vaccines. Lastly, we present some of the current limitations to the clinical applications of compounds from Aloe, especially from A. vera.

Aloe arborescens: In Vitro Screening of Genotoxicity, Effective Inhibition of Enzyme Characteristics for Disease Etiology, and Microbiological Activity

The present study assessed the genotoxicity, the possibility of inhibiting selected enzymes, and the microbial activity of lyophilisate from 3-year-old A. arborescens leaves obtained from controlled crops. The lyophilisate from 3-year-old A. arborescens leaves was standardized for aloin A and aloenin A content. Moreover, concentrations of polyphenolic compounds and phenolic acids were determined. The first stage of the research was to determine genotoxicity using the comet test, which confirmed the safety of A. arborescens. Assays of enzymatic inhibition were performed for hyaluronidase (IC50 = 713.24 ± 41.79 µg/mL), α-glucosidase (IC50 = 598.35 ± 12.58 µg/mL), acetylcholinesterase and butyrylcholinesterase (1.16 vs. 0.34 µM of eserine/g d.m., respectively). The next stage of the research was to determine the ability of the healing properties using the scratch test, which showed a positive response using the extract. Microbial activity was evaluated and obtained against Gram-negative and Gram-positive bacteria and yeasts. We concluded that A. arborescens leaf gel meets the important conditions for plant raw materials to obtain semi-solid forms of herbal medicinal products.

Identification of Natural Inhibitors Against SARS-CoV-2 Drugable Targets Using Molecular Docking, Molecular Dynamics Simulation, and MM-PBSA Approach

The present study explores the SARS-CoV-2 drugable target inhibition efficacy of phytochemicals from Indian medicinal plants using molecular docking, molecular dynamics (MD) simulation, and MM-PBSA analysis. A total of 130 phytochemicals were screened against SARS-CoV-2 Spike (S)-protein, RNA-dependent RNA polymerase (RdRp), and Main protease (M^pro). Result of molecular docking showed that Isoquercetin potentially binds with the active site/protein binding site of the Spike, RdRP, and Mpro targets with a docking score of -8.22, -6.86, and -9.73 kcal/mole, respectively. Further, MS 3, 7-Hydroxyaloin B, 10-Hydroxyaloin A, showed -9.57, -7.07, -8.57 kcal/mole docking score against Spike, RdRP, and M^pro targets respectively. The MD simulation was performed to study the favorable confirmation and energetically stable complex formation ability of Isoquercetin and 10-Hydroxyaloin A phytochemicals in M^pro-unbound/ligand bound/standard inhibitor bound system. The parameters such as RMSD, RMSF, Rg, SASA, Hydrogen-bond formation, energy landscape, principal component analysis showed that the lead phytochemicals form stable and energetically stabilized complex with the target protein. Further, MM-PBSA analysis was performed to compare the Gibbs free energy of the M^pro-ligand bound and standard inhibitor bound complexes. The analysis revealed that the His-41, Cys145, Met49, and Leu27 amino acid residues were majorly responsible for the lower free energy of the complex. Drug likeness and physiochemical properties of the test compounds showed satisfactory results. Taken together, the study concludes that that the Isoquercetin and 10-Hydroxyaloin A phytochemical possess significant efficacy to bind SARS-Cov-2 M^pro active site. The study necessitates further in vitro and in vivo experimental validation of these lead phytochemicals to assess their anti-SARS-CoV-2 potential.

p-cymene impairs SARS-CoV-2 and Influenza A (H1N1) viral replication: In silico predicted interaction with SARS-CoV-2 nucleocapsid protein and H1N1 nucleoprotein

Therapeutic regimens for the COVID-19 pandemics remain unmet. In this line, repurposing of existing drugs against known or predicted SARS-CoV-2 protein actions have been advanced, while natural products have also been tested. Here, we propose that p-cymene, a natural monoterpene, can act as a potential novel agent for the treatment of SARS-CoV-2-induced COVID-19 and other RNA-virus-induced diseases (influenza, rabies, Ebola). We show by extensive molecular simulations that SARS-CoV-2 C-terminal structured domain contains a nuclear localization signal (NLS), like SARS-CoV, on which p-cymene binds with low micromolar affinity, impairing nuclear translocation of this protein and inhibiting viral replication, as verified by preliminary in vitro experiments. A similar mechanism may occur in other RNA-viruses (influenza, rabies and Ebola), also verified in vitro for influenza, by interaction of p-cymene with viral nucleoproteins, and structural modification of their NLS site, weakening its interaction with importin A. This common mechanism of action renders therefore p-cymene as a possible antiviral, alone, or in combination with other agents, in a broad spectrum of RNA viruses, from SARS-CoV-2 to influenza A infections.

In vivo immuno - and angiomodulatory effects of Aloe arborescens folii recentis extractum siccum (AAES) in mice

Introduction

AAES is a powdered form of Biostymina, herbal medicinal product of Phytopharm Klęka S.A., a water extract of Aloe arborescens Mill. leaves. Aloe arborescens Mill. (woody aloe, tree-like aloe) is known to have several traditional medicinal properties including anti-inflammatory, immunomodulatory, antiviral and antimicrobial activity.

Objective

The aim of this work was to study the in vivo effect of AAES on cellular (leukocyte-induced cutaneous angiogenesis, LIA test, and proliferative response to PHA) and humoral (anti-SRBC antibody response) immunity in mice.

Methods

Balb/c mice were fed AAES from 0.5 to 75 mg/kg body mass for seven days before grafting their splenocytes intradermally to F1 (Balb/cxC3H) recipients (LIA test). Neovascular reaction was evaluated 72 h later in dissection microscope. Spleen cell cultures were incubated with 0.5, 1 and 2 μg/ml of PHA. After 48 h of incubation, tritiated thymidine was added. After further 24 h, cells were harvested (Skatron) and incorporation of tritiated thymidine was measured using Beta-scintillation counter. Balb/c mice were fed for 7 days with AAES, then immunized intraperitoneally with 5% SRBC suspension and 7 days later the antibody response was measured with hemagglutination test.

Results

Neovascular reaction was significantly higher in groups grafted with splenocytes collected from all AAES fed donors than from the controls. The proliferation of splenocytes taken from mice fed AAES at doses ranging from 0.5 mg/kg to 7.5 mg/kg was stimulated in all cultures. Suppression of proliferation was observed in cell cultures derived from mice fed with higher doses of AAES. Stimulation of anti-SRBC antibody production was seen in mice fed both 2.5 and 7.5 mg/kg dose of AAES.

Conclusion

Powdered form of Biostymina (AAES) might be useful in the treatment of patients with ischaemia of tissues and organs (myocardial infarction, stroke, necrosis) and in deficiency in the production of immune cells and growth factors (infections, chronic wound healing, ulceration and bone fusion).

Quercetin as a Natural Therapeutic Candidate for the Treatment of Influenza Virus

The medical burden caused by respiratory manifestations of influenza virus (IV) outbreak as an infectious respiratory disease is so great that governments in both developed and developing countries have allocated significant national budget toward the development of strategies for prevention, control, and treatment of this infection, which is seemingly common and treatable, but can be deadly. Frequent mutations in its genome structure often result in resistance to standard medications. Thus, new generations of treatments are critical to combat this ever-evolving infection. Plant materials and active compounds have been tested for many years, including, more recently, active compounds like flavonoids. Quercetin is a compound belonging to the flavonols class and has shown therapeutic effects against influenza virus. The focus of this review includes viral pathogenesis as well as the application of quercetin and its derivatives as a complementary therapy in controlling influenza and its related symptoms based on the targets. We also touch on the potential of this class of compounds for treatment of SARS-COV-2, the cause of new pandemic.

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

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

Aloe vera and its Components Inhibit Influenza A Virus-Induced Autophagy and Replication

Aloe vera ethanol extract (AVE) reportedly has significant anti-influenza virus activity, but its underlying mechanisms of action and constituents have not yet been completely elucidated. Previously, we have confirmed that AVE treatment significantly reduces the viral replication of green fluorescent protein-labeled influenza A virus in Madin-Darby canine kidney (MDCK) cells. In addition, post-treatment with AVE inhibited viral matrix protein 1 (M1), matrix protein 2 (M2), and hemagglutinin (HA) mRNA synthesis and viral protein (M1, M2, and HA) expressions. In this study, we demonstrated that AVE inhibited autophagy induced by influenza A virus in MDCK cells and also identified quercetin, catechin hydrate, and kaempferol as the active antiviral components of AVE. We also found that post-treatment with quercetin, catechin hydrate, and kaempferol markedly inhibited M2 viral mRNA synthesis and M2 protein expression. A docking simulation suggested that the binding affinity of quercetin, catechin hydrate, and kaempferol for the M2 protein may be higher than that of known M2 protein inhibitors. Thus, the inhibition of autophagy induced by influenza virus may explain the antiviral activity of AVE against H1N1 or H3N2. Aloe vera extract and its constituents may, therefore, be potentially useful for the development of anti-influenza agents.

The anti-hepatitis B virus therapeutic potential of anthraquinones derived from Aloe vera

Although the approved hepatitis B virus (HBV)-polymerase inhibitors (e.g., lamivudine) often lead to drug-resistance, several natural products have shown promising efficacies. Though Aloe vera (AV) gel and its constituents are shown inhibitors of many viruses, their anti-HBV activity still remains elusive. We therefore, tested the anti-HBV potential of AV extract and its anthraquinones in hepatoma cells, including molecular docking, high-performance thin layer chromatography (HPTLC), and cytochrome P450 (CYP3A4) activation analyses. Our anti-HBV assays (HBsAg/HBeAg Elisa) showed maximal inhibition of viral antigens production by aloe-emodin (~83%) > chrysophanol (~62%) > aloin B (~61%) > AV extract (~37%) in HepG2.2.15 cells. Interestingly, the effect of aloe-emodin was comparable with lamivudine (~86%). Moreover, sequential treatment with lamivudine (pulse) followed by aloe-emodin (chase) enhanced the efficacy of monotherapy by ~12%. Docking (AutoDock Vina) of the anthraquinones indicated strong interactions with HBV-polymerase residues that formed stable complexes with high Gibbs's free energy. Further, identification of aloe-emodin and aloin B by validated HPTLC in AV extract strongly endorsed its anti-HBV potential. In addition, our luciferase-reporter gene assay of transfected HepG2 cells showed moderate induction of CYP3A4 by aloe-emodin. In conclusion, this is the first report on anti-HBV potential of AV-derived anthraquinones, possibly via HBV-polymerase inhibition. Of these, although aloin B exhibits novel antiviral effect, aloe-emodin appears as the most promising anti-HBV natural drug with CYP3A4 activating property towards its enhanced therapeutic efficacy.

Therapeutic potential of Aloe vera-A miracle gift of nature

BACKGROUND

Aloe vera is commonly used in the primary health care of human beings since time immemorial. It is an herb widely used in various traditional systems of medicine worldwide. Systematic and scientific investigation on A. vera as a medicinal plant has drawn considerable attention, and many laboratories are involved in isolation, characterization and evaluation of phytoconstituents for their nutraceutical and pharmaceutical applications.

PURPOSE

The aim of this study was to provide an overview of the phytochemical, biological and medicinal attributes of A. vera against various diseases with special emphasis on underlying mechanisms of action.

METHODS

PubMed, EBOSCO host, Science Direct, Scopus, and Cochrane library databases were utilized to search literature published between1977 and 2019 (till March). Major keywords used in various combinations included: Aloe vera, phytochemistry, metabolism, pharmacological activity, prevention, treatment, health, disease, in vivo, in vitro, and clinical studies.

RESULTS

Various biological and pharmacological activities of A. vera, such as antioxidant, anti-inflammatory, immuno-modulatory, antimicrobial, antiviral, antidiabetic, hepatoprotective, anticancer, and skin-protective and wound-healing responses, have been attributed to the presence of many active compounds, including anthraquinones, anthrones, chromones, flavonoids, amino acids, lipids, carbohydrates, vitamins and minerals.

CONCLUSION

Based on various preclinical studies, A. vera constituents have enormous potential to prevent and treat various diseases. Randomized clinical trials are needed to understand the full therapeutic potential of this unique medicinal plant.

Effects of gamma radiation on the bioactivity of medicinal and aromatic plants: Mentha × piperita L., Thymus vulgaris L. and Aloysia citrodora Paláu as case studies

Irradiation is a feasible and safe decontamination technique, being applied to several types of foods including edible and medicinal plants. The aim of this study was to evaluate the effects of different gamma radiation doses (1, 5 and 10 kGy) on the individual profile of phenolic compounds determined by HPLC-DAD-ESI/MS, and the bioactive potential (cytotoxic, virucidal, and antimicrobial activities) of Aloysia citrodora Paláu (lemon verbena), Mentha × piperita L. (peppermint) and Thymus vulgaris L. (thyme). The observed cytotoxic activity varied with the plant and with the applied dose, being higher in Thymus vulgaris irradiated with 10 kGy. The virucidal activity was also dependent on the radiation dose, but was preserved with irradiation treatment. Gamma rays had no effect on the antimicrobial activity of the studied plants. Otherwise, the effects of gamma radiation on the phenolic profile were heterogeneous, with an increase in some compounds and decrease in others, depending on the species and on the radiation dose.

Therapeutic effects of Aloe spp. in traditional and modern medicine: A review

Traditional medicine is a useful guide in medical sciences. In the Islamic Iranian traditional medicine, the medicinal properties of many plants have been mentioned that could be exploited in drug discovery. We aimed to explore the nature and properties of Aloe spp. As described in some major Islamic traditional texts including Ferdows al-Hekmah fi'l-Tibbe (The Paradise of Wisdom in Medicine), Al-Hawi fi'l-Tibb (Comprehensive Book of Medicine), Kamel al-Sanaat al-Tibbyyah (Complete Book of the Medical Art), Al-Qanun fi'l-Tibb (Canon of Medicine), Zakhireh Kharazmshahi (Treasure of Kharazmshah), and Makhzan al-Adwiah (Drug Treasure), and assess the conformity of traditional medicine instructions with the findings of modern pharmacological studies. Gastrointestinal activities, hepato-protective properties, beneficial effects against skin problems such as wounds, injuries, and infective diseases are among the most frequently mentioned properties of Aloe spp. Several activities of Aloe spp. described in traditional medicine have been the subject of recent in vitro and in vivo studies as well as clinical trials. Owing to the positive findings, different preparations of Aloe spp. are now present in pharmaceutical markets such as Aloe cosmetic products. On the other hand, there are many traditional therapeutic effects of Aloe spp. which have not been studied and require confirmatory experimental or clinical investigations. It is hoped that the present study could stimulate further research on the unexplored aspects of the medicinal properties of Aloe spp.

NEU3 inhibitory effect of naringin suppresses cancer cell growth by attenuation of EGFR signaling through GM3 ganglioside accumulation

Naringin, which is one of the flavonoids contained in citrus fruits, is well known to possess various healthy functions to humans. It has been reported that naringin suppresses cancer cell growth in vitro and in vivo, although the underlying mechanisms are not fully understood. Recently, the roles of glycoconjugates, such as gangliosides, in cancer cells have been focused because of their regulatory effects of malignant phenotypes. Here, to clarify the roles of naringin in the negative-regulation of cancer cell growth, the alteration of glycoconjugates induced by naringin exposure and its significance on cell signaling were investigated. Human cancer cells, HeLa and A549, were exposed to various concentrations of naringin. Naringin treatment induced the suppression of cell growth toward HeLa and A549 cells accompanied with an increase of apoptotic cells. In naringin-exposed cells, GM3 ganglioside was drastically increased compared to the GM3 content prior to the treatment. Furthermore, naringin inhibited NEU3 sialidase, a GM3 degrading glycosidase. Similarly, NEU3 inhibition activities were also detected by other flavanone, such as hesperidin and neohesperidin dihydrocalcone, but their aglycones showed less inhibitions. Naringin-treated cancer cells showed suppressed EGFR and ERK phosphorylation levels. These results suggest a novel mechanism of naringin in the suppression of cancer cell growth through the alteration of glycolipids. NEU3 inhibitory effect of naringin induced GM3 accumulation in HeLa and A549 cells, leading the attenuation of EGFR/ERK signaling accompanied with a decrease in cell growth.