A Novel Flavonoid Composition Targets Androgen Receptor Signaling and Inhibits Prostate Cancer Growth in Preclinical Models

Toxicological assessment of the Achyrocline satureioides aqueous extract in the Caenorhabditis elegans alternative model

Achyrocline satureioides, popularly called "marcela" in Brazil, is used in traditional medicine in South America. A. satureioides, inflorescences are used for many conditions, including to minimize the Sars-Cov-2 symptoms. Therefore, the aim of this study was to determine the toxicity profile of A. satureioides aqueous extract (ASAE), using the Caenorhabditis elegans (C. elegans) alternative model. Survival, reproduction, development, and transgenerational assays were performed. The effects of ASAE were investigated under conditions of thermal stress and presence of oxidant hydrogen peroxide (H2O2). In addition, C. elegans strains containing high antioxidant enzyme levels and elevated lineages of daf-16, skn-1 and daf-2 regulatory pathways were examined. The ASAE LC50 value was found to be 77.3 ± 4 mg/ml. The concentration of ASAE 10 mg/ml (frequently used in humans) did not exhibit a significant reduction in worm survival at either the L1 or L4 stage, after 24 or 72 hr treatment. ASAE did not markedly alter the body area. In N2 strain, ASAE (10 or 25 mg/ml) reversed the damage initiated by H2O2. In addition, ASAE protected the damage produced by H2O2 in strains containing significant levels of sod-3, gst-4 and ctl - 1,2,3, suggesting modulation in these antioxidant systems by this plant extract. ASAE exposure activated daf-16 and skn-1 stress response transcriptional pathways independently of daf-2, even under extreme stress. Data suggest that ASAE, at the concentrations tested in C. elegans, exhibits a reliable toxicity profile, which may contribute to consideration for safe use in humans.

Upregulation of key factors of viral entry of corona- and influenza viruses upon TLR3-signaling in cells from the respiratory tract and clinical treatment options by 1,8-Cineol

At the end of the 2019 coronavirus pandemic (COVID-19), highly contagious variants of coronaviruses had emerged. Together with influenza viruses, different variants of the coronavirus currently cause most colds and require appropriate drug treatment. We have investigated the expression of important factors for the replication of these viruses, namely transmembrane protease serine subtype 2 (TMPRSS2), neuropilin1 (NRP1), and angiotensin converting enzyme 2 (ACE2) or tumor necrosis factor-α (TNF-α) after toll like receptor-3 (TLR-3) stimulation using RT-qPCR and flow cytometry (FC) analysis. As model served primary fibroblasts derived from the lung and nasal cavity, as well as epidermal stem cells and fully matured respiratory epithelium. The stimulated cell cultures were treated with pharmaceuticals (Dexamethasone and Enzalutamide) and the outcome was compared with the phytomedicine 1,8-Cineol. The stimulation of TLR3 is sufficient to induce the expression of exactly those targets that were highly expressed in the corresponding culture type, specifically ACE2 and TMPRSS2 in respiratory epithelial stem cells and NRP1 in fibroblast cells. It seems this self-perpetuating cycle of infection-driven upregulation of key viral replication factors by the innate immune system represents an evolutionary advantage for viruses using these transcripts as viral replication factors. Likewise, to the standard pharmaceuticals with proven clinical efficiency, 1,8-Cineol was able to disrupt this self-perpetuating cycle. Considering the minor side effects and negligible pharmacological interactions with other drugs, it is conceivable that an adjuvant or combinatorial therapy with 1,8-Cineol for respiratory diseases caused by corona- or influenza viruses would be beneficial.

The Pros and Cons of Estrogens in Prostate Cancer: An Update with a Focus on Phytoestrogens

The role of estrogens in prostate cancer (PCa) is shrouded in mystery, with its actions going from angelic to devilish. The findings by Huggins and Hodges establishing PCa as a hormone-sensitive cancer have provided the basis for using estrogens in therapy. However, despite the clinical efficacy in suppressing tumor growth and the panoply of experimental evidence describing its anticarcinogenic effects, estrogens were abolished from PCa treatment because of the adverse secondary effects. Notwithstanding, research work over the years has continued investigating the effects of estrogens, reporting their pros and cons in prostate carcinogenesis. In contrast with the beneficial therapeutic effects, many reports have implicated estrogens in the disruption of prostate cell fate and tissue homeostasis. On the other hand, epidemiological data demonstrating the lower incidence of PCa in Eastern countries associated with a higher consumption of phytoestrogens support the beneficial role of estrogens in counteracting cancer development. Many studies have investigated the effects of phytoestrogens and the underlying mechanisms of action, which may contribute to developing safe estrogen-based anti-PCa therapies. This review compiles the existing data on the anti- and protumorigenic actions of estrogens and summarizes the anticancer effects of several phytoestrogens, highlighting their promising features in PCa treatment.

The flavonoid quercetin decreases ACE2 and TMPRSS2 expression but not SARS-CoV-2 infection in cultured human lung cells

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) binds to angiotensin-converting enzyme 2 (ACE2) on host cells, via its spike protein, and transmembrane protease, serine 2 (TMPRSS2) cleaves the spike-ACE2 complex to facilitate virus entry. As rate-limiting steps for virus entry, modulation of ACE2 and/or TMPRSS2 may decrease SARS-CoV-2 infectivity and COVID-19 severity. In silico modeling suggested the natural bioactive flavonoid quercetin can bind to ACE2 and a recent randomized clinical trial demonstrated that oral supplementation with quercetin increased COVID-19 recovery. A range of cultured human cells were assessed for co-expression of ACE2 and TMPRSS2. Immortalized Calu-3 lung cells, cultured and matured at an air-liquid interface (Calu-3-ALIs), were established as the most appropriate. Primary bronchial epithelial cells (PBECs) were obtained from healthy adult males (N = 6) and cultured under submerged conditions to corroborate the outcomes. Upon maturation or reaching 80% confluence, respectively, the Calu-3-ALIs and PBECs were treated with quercetin, and mRNA and protein expression were assessed by droplet digital PCR and ELISA, respectively. SARS-CoV-2 infectivity, and the effects of pre- and co-treatment with quercetin, was assessed by median tissue culture infectious dose assay. Quercetin dose-dependently decreased ACE2 and TMPRSS2 mRNA and protein in both Calu-3-ALIs and PBECs after 4 h, while TMPRSS2 remained suppressed in response to prolonged treatment with lower doses (twice daily for 3 days). Quercetin also acutely decreased ADAM17 mRNA, but not ACE, in Calu-3-ALIs, and this warrants further investigation. Calu-3-ALIs, but not PBECs, were successfully infected with SARS-CoV-2; however, quercetin had no antiviral effect, neither directly nor indirectly through downregulation of ACE2 and TMPRSS2. Calu-3-ALIs were reaffirmed to be an optimal cell model for research into the regulation of ACE2 and TMPRSS2, without the need for prior genetic modification, and will prove valuable in future coronavirus and respiratory infectious disease work. However, our data demonstrate that a significant decrease in the expression of ACE2 and TMPRSS2 by a promising prophylactic candidate may not translate to infection prevention.

Recent advances in flavonoid compounds for the treatment of prostate cancer

Prostate cancer is a malignant epithelial tumor of the prostate gland and is the most common malignant tumor of the male genitourinary system. Pharmacological therapies, including chemotherapy and androgen deprivation therapy, play a key role in the treatment of prostate cancer. However, drug resistance and side effects limit the use of these drugs and so there is a need for new drug therapies for prostate cancer patients. Flavonoids, with their wide range of sources and diverse biological activities, have attracted much attention in the field of anti-tumor drug screening. In 2016, at least 58 flavonoids were reported to have anti-prostate cancer activity. In recent years, six additional flavonoid compounds have been found to have anti-prostate cancer potential. In this review, we have collected a large amount of evidence on the anti-prostate cancer effects of these six flavonoids, including a large number of cellular experiments and a small number of preclinical animal experiments. In addition, we predicted their drug-forming properties using Schrödinger's QikProp software and ADMETlab due to the lack of in vivo pharmacokinetic data for the six compounds. In conclusion, this review has fully confirmed the anti-prostate cancer effects of these six flavonoids, summarized their mechanisms of action and predicted their druggability. It provides a reference for the further development of these compounds into anti-prostate cancer drugs.

Astragalus membranaceus Extract Induces Apoptosis via Generation of Reactive Oxygen Species and Inhibition of Heat Shock Protein 27 and Androgen Receptor in Prostate Cancers

Although Astragalus membranaceus is known to have anti-inflammatory, anti-obesity, and anti-oxidant properties, the underlying apoptotic mechanism of Astragalus membranaceus extract has never been elucidated in prostate cancer. In this paper, the apoptotic mechanism of a water extract from the dried root of Astragalus membranaceus (WAM) was investigated in prostate cancer cells in association with heat shock protein 27 (HSP27)/androgen receptor (AR) signaling. WAM increased cytotoxicity and the sub-G1 population, cleaved poly (ADP-ribose) polymerase (PARP) and cysteine aspartyl-specific protease 3 (caspase 3), and attenuated the expression of B-cell lymphoma 2 (Bcl-2) in LNCaP cells after 24 h of exposure. Consistently, WAM significantly increased the number of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive LNCaP cells. WAM decreased the phosphorylation of HSP27 on Ser82 and inhibited the expression of the AR and prostate-specific antigen (PSA), along with reducing the nuclear translocation of p-HSP27 and the AR via the disturbed binding of p-HSP27 with the AR in LNCaP cells. WAM consistently inhibited the expression of the AR and PSA in dihydrotestosterone (DHT)-treated LNCaP cells. WAM also suppressed AR stability, both in the presence and absence of cycloheximide, in LNCaP cells. Taken together, these findings provide evidence that WAM induces apoptosis via the inhibition of HSP27/AR signaling in prostate cancer cells and is a potent anticancer candidate for prostate cancer treatment.

Achyrocline satureioides as an adjuvant therapy for the management of mild viral respiratory infections in the context of COVID-19: Preliminary results of a randomized, placebo-controlled, and open-label clinical trial

We evaluated the impact of an Achyrocline satureioides inflorescence infusion on the clinical outcomes of viral respiratory infections, including those caused by SARS-CoV-2, in a monocentric, randomized, open-label, placebo-controlled clinical trial. Patients with symptoms of viral respiratory infection, including suspected cases of COVID-19, were included and assigned to receive either A. satureioides (n = 57) or Malus domestica (n = 67) infusions twice a day for 14 days. All participants were included before the RT-PCR results, performed using a nasopharyngeal swab. The patients were further divided into subgroups according to real-time polymerase chain reaction results: SARS-CoV-2-positive and SARS-CoV-2-negative subgroups for statistical analyses. We assessed clinical outcomes, such as the latency to resolution of cough, dyspnea, fever, sore throat, chest pain, smell and taste dysfunctions, diarrhea, nausea, abdominal pain, and loss of appetite; hospitalization; and mortality with questionnaires and medical records. The subjects that received early A. satureioides infusion showed a significant reduction in the average number of days with respiratory and neurological symptoms compared with the control group (M. domestica infusion). We conclude that A. satureioides is a safe agent and, in combination with standard care, improves viral respiratory infection symptoms, especially those related to COVID-19.

Therapeutic Importance of Kaempferol in the Treatment of Cancer through the Modulation of Cell Signalling Pathways

Plant-derived flavonoids are considered natural nontoxic chemo-preventers and have been widely studied for cancer treatment in recent decades. Mostly all flavonoid compounds show significant anti-inflammatory, anticancer and antioxidant properties. Kaempferol (Kmp) is a well-studied compound and exhibits remarkable anticancer and antioxidant potential. Kmp can regulate various cancer-related processes and activities such as cell cycle, oxidative stress, apoptosis, proliferation, metastasis, and angiogenesis. The anti-cancer properties of Kmp primarily occur via modulation of apoptosis, MAPK/ERK1/2, P13K/Akt/mTOR, vascular endothelial growth factor (VEGF) signalling pathways. The anti-cancer property of Kmp has been recognized in several in-vivo and in-vitro studies which also includes numerous cell lines and animal models. This flavonoid possesses toxic activities against only cancer cells and have restricted toxicity on healthy cells. In this review, we present extensive research investigations about the therapeutic potential of Kmp in the management of different types of cancers. The anti-cancer properties of Kmp are discussed by concentration on its capability to target molecular-signalling pathway such as VEGF, STAT, p53, NF-κB and PI3K-AKT signalling pathways. The anti-cancer property of Kmf has gained a lot of attention, but the accurate action mechanism remains unclear. However, this natural compound has a great pharmacological capability and is now considered to be an alternative cancer treatment.

Assessing the Mechanism of Action of “Fructus Ligustri Lucidi-Cuscutae Semen” in Prostate Cancer Treatment Using Network Pharmacology and Molecular Docking

Objective

To explore the mechanism of action of “Fructus Ligustri Lucidi-Cuscutae Semen” in the treatment of prostate cancer using network pharmacology and molecular docking.

Methods

The active ingredients and targets of “Fructus Ligustri Lucidi-Cuscutae Semen” were obtained by searching the TCMSP and DrugBank databases. These were matched and corrected using the UniProt platform. A drug “active ingredient-target” network map was constructed using Cytoscape 3.8.0. Prostate cancer-related targets were acquired from GeneCards, Disgenet, DrugBank, and other databases. The protein-protein interaction (PPI) network between the drug and prostate cancer was constructed with BioGenet; the crossover network of the two targets was extracted derive the key targets of “Fructus Ligustri Lucidi-Cuscutae Semen” for prostate cancer treatment. We used the Metascape platform for GO and KEGG enrichment analysis of the key targets. AutoDockTools1.5.6 and PyMOL software were used to perform molecular docking.

Results

We obtained 13 active ingredients, 221 drug targets, 1511 prostate cancer targets (including 221 key targets), and 305 KEGG pathways from “Fructus Ligustri Lucidi-Cuscutae Semen.” Paclitaxel, quercetin, kaempferol, TP53, β-sitosterol, EGFR, and ESR1 in “Fructus Ligustri Lucidi-Cuscutae Semen” showed good docking activity.

Conclusion

“Fructus Ligustri Lucidi-Cuscutae Semen” is a valuable clinical guide for the treatment of prostate cancer with multicomponent, multitarget, and multipathway characteristics.

α-Terthienyl induces prostate cancer cell death through inhibiting androgen receptor expression

Prostate cancer is a disease that often occurs in elderly men. Androgen receptor signaling pathway runs through the occurrence and development of prostate cancer. Thereby, targeting androgen receptor is a crucial strategy for the treatment of prostate cancer. α-Terthienyl, which has been used as photosensitive activator and insecticide, is a natural compound rich in marigold. In the present study, we found α- terthienyl could inhibit the cell viability of four prostate cancer cell lines, especially on LNCaP and 22Rv1 cells which endogenously express androgen receptor. Then we proved that it could inhibit the proliferation of prostate cancer cells and induce apoptosis of prostate cancer cells by plate clone formation assay and flow cytometry respectively. Furthermore, we found α-terthienyl could inhibit androgen receptor nuclear translocation, reduce androgen receptor expression, reduce the mRNA and protein expression of androgen receptor target genes (KLK3, TMPRSS2, PCA3) and nuclear proliferation antigen Ki67 and PCNA. In addition, it inhibited the expression and phosphorylation of Akt protein while increasing the expression of tumor suppressor p27. Besides, we constructed a mouse xenograft prostate cancer model and confirmed that α-terthienyl also inhibited the growth of prostate cancer in vivo. In conclusively, α-terthienyl played an anti-prostate cancer role by inhibiting both the expression of androgen receptor and the transduction of its signal pathway, suggesting that it is a promising natural small molecule for the treatment of prostate cancer.

Impacts of endocrine-disrupting chemicals on prostate function and cancer

Because of their historical mode of action, endocrine-disrupting chemicals (EDCs) are associated with sex-steroid receptors, namely the two estrogen receptors (ERα and ERβ) and the androgen receptor (AR). Broadly, EDCs can modulate sex-steroid receptor functions. They can also indirectly impact the androgen and estrogen pathways by influencing steroidogenesis, expression of AR or ERs, and their respective activity as transcription factors. Additionally, many of these chemicals have multiple cellular targets other than sex-steroid receptors, which results in a myriad of potential effects in humans. The current article reviews the association between prostate cancer and the endocrine-disrupting functions of four prominent EDC families: bisphenols, phthalates, phytoestrogens, and mycoestrogens. Results from both in vitro and in vivo models are included and discussed to better assess the molecular mechanisms by which EDCs can modify prostate biology. To overcome the heterogeneity of results published, we established common guidelines to properly study EDCs in the context of endocrine diseases. Firstly, the expression of sex-steroid receptors in the models used must be determined before testing. Then, in parallel to EDCs, pharmacological compounds acting as positive (agonists) and negative controls (antagonists) have to be employed. Finally, EDCs need to be used in a precise range of concentrations to modulate sex-steroid receptors and avoid off-target effects. By adequately integrating molecular endocrinology aspects in EDC studies and identifying their underlying molecular mechanisms, we will truly understand their impact on prostate cancer and distinguish those that favor the progression of the disease from those that slow down tumor development.

Natural medicinal plant products as an immune-boosters: A possible role to lessen the impact of Covid-19

Transmissible Covid-19, caused by novel corona virus since last of 2019 has outspread widely until now. Where, India was the second most affected country and 3rd in mortality rate. In world ancient history, medicinal plants were played a crucial role to cure several diseases. In present study, we show some novel natural medicinal plant metabolites as the potential inhibitors against papain-like protease (PLpro), main protease (Mpro) and RNA-dependent RNA polymerase (RdRp), transmembrane proteinase Serine 2 (TMPRSS2) and angiotensin converting enzyme-2 (ACE-2) of Covid-19. Plant metabolites were having been proven to inhibit SARS-CoVs, which also actively walkable against Covid-19.

Polyphenols as anticancer agents: Toxicological concern to healthy cells

Polyphenols are a group of diverse chemical compounds present in a wide range of plants. Various biological properties such as antiallergic, antiviral, antibacterial, anticarcinogenic, antiinflammatory, antithrombotic, vasodilatory, and hepatoprotective effect of different polyphenols have been reported in the scientific literature. The major classes of polyphenols are flavonoids, stilbenoids, lignans, and polyphenolic acids. Flavonoids are a large class of food constituents comprising flavones, isoflavanones, flavanones, flavonols, catechins, and anthocyanins sub-classes. Even with seemingly broad biological activities, their use is minimal clinically. Among the other concurrent problems such as limited bioavailability, rapid metabolism, untargeted delivery, the toxicity associated with these polyphenols has been a topic of concern lately. These polyphenols have been reported to result in different forms of toxicity that include organ toxicity, genotoxicity, mutagenicity, cytotoxicity, etc. In the present article, we have tried to unravel the toxicological aspect of these polyphenols to healthy cells. Further high-quality studies are needed to establish the clinical efficacy and toxicology concern leading to further exploration of these polyphenols.

Advance toward isolation, extraction, metabolism and health benefits of kaempferol, a major dietary flavonoid with future perspectives

As a major ubiquitous secondary metabolite, flavonoids are widely distributed in planta. Among flavonoids, kaempferol is a typical natural flavonol in diets and medicinal plants with myriad bioactivities, such as anti-inflammatory activity, anti-cancer activity, antioxidant activity, and anti-diabetic activity. However, the natural sources, absorption and metabolism as well as the bioactivities of kaempferol have not been reviewed comprehensively and systematically. This review highlights the latest research progress and the effect of kaempferol in the prevention and treatment of various chronic diseases, as well as its protective health effects, and provides a theoretical basis for future research to be used in nutraceuticals. Further, comparison of the different extraction and analytical methods are presented to highlight the most optimum for PG recovery and its detection in plasma and body fluids. Such review aims at improving the value-added applications of this unique dietary bioactive flavonoids at commercial scale and to provide a reference for its needed further development.

Flavonoid Calycopterin Induces Apoptosis in Human Prostate Cancer Cells In-vitro

Prostate cancer is enumerated as one of the most prevalent cancers in men, with a mortality rate of 18%. Chemotherapy is considered as a common strategy for cancer treatment; however, toxic side effects and drug resistance associated with chemotherapy are major drawbacks with this approach. It is well known that a diet rich in flavonoids can reduce the incidence of many types of cancer in a significant manner, and it was proved that methoxy flavones have greater bioavailability compared to the nonmethylated ones. Calycopterin is a tetramethoxy flavone which was demonstrated to have anti-proliferative effects on colon, gastric, and osteosarcoma cancer cells. Therefore, in the current study, we have evaluated the apoptotic effects of this flavonoid on two prostate cancer cell lines in-vitro. The MTT assay revealed that after 48 h treatment with this flavonoid, cell viability reduced to 50% compared to the control group. However, calycopterin treatment of healthy HUVEC did not cause any significant reduction in cell viability. Moreover, the clonogenic assay demonstrated that after 14 days, colony size and numbers reduced significantly in calycopterin treated cells. In addition, the percentage of the sub-G1 population in calycopterin-treated cells augmented significantly compared to untreated group. Also, calycopterin-treated cells demonstrated shiny condensed nuclei with fragmented DNA indicative of apoptosis. Finally, a significant reduction in the migration ability was observed in both lines subjected to calycopterin after 48 h. To conclude, our results demonstrated the apoptotic and anti-metastatic effects of calycopterin in both hormone-dependent and independent prostate cancer cell lines.

Therapeutic effect of kaempferol on atopic dermatitis by attenuation of T cell activity via interaction with multidrug resistance-associated protein 1

BACKGROUND AND PURPOSE

Kaempferol is a natural flavonoid widely investigated in various fields due to its antioxidant, anti-cancer, and anti-inflammatory activities, but few studies have shown its inhibitory effect on T cell activation. This study examined the therapeutic potential of kaempferol in atopic dermatitis by modulating T cell activation.

EXPERIMENTAL APPROACH

Effects of kaempferol on T cell activation and the underlying mechanisms were investigated in Jurkat cells and mouse CD4⁺ T cells. A model of atopic dermatitis in mice was used to determine its therapeutic potential on T cell-mediated conditions in vivo. Western blots, RT-PCR, pulldown assays and ELISA were used, along with histological analysis of skin.

KEY RESULTS

Pretreatment with kaempferol reduced CD69 expression and production of inflammatory cytokines including IL-2 from activated Jurkat cells and murine CD4⁺ T cells without cytotoxicity. Pulldown assays revealed that kaempferol physically binds to MRP-1 in T cells, inhibiting the action of MRP-1. In activated T cells, kaempferol suppressed JNK phosphorylation and the TAK1-IKKα mediated NF-κB pathway. Oral administration of kaempferol to mice showed improved manifestation of atopic dermatitis, a T cell-mediated condition. Western blot results showed that, as in the in vitro studies, decreased phosphorylation of JNK was associated with down-regulated MRP-1 activity in vivo, in the kaempferol-treated mice in the atopic dermatitis model.

CONCLUSION AND IMPLICATIONS

Kaempferol regulates T cell activation by inhibiting MRP-1 activity in activated T cells, thus showing protective effects against T cell mediated disease in vivo.

Role of Carbon Monoxide in Host-Gut Microbiome Communication

Nature is full of examples of symbiotic relationships. The critical symbiotic relation between host and mutualistic bacteria is attracting increasing attention to the degree that the gut microbiome is proposed by some as a new organ system. The microbiome exerts its systemic effect through a diverse range of metabolites, which include gaseous molecules such as H₂, CO₂, NH₃, CH₄, NO, H₂S, and CO. In turn, the human host can influence the microbiome through these gaseous molecules as well in a reciprocal manner. Among these gaseous molecules, NO, H₂S, and CO occupy a special place because of their widely known physiological functions in the host and their overlap and similarity in both targets and functions. The roles that NO and H₂S play have been extensively examined by others. Herein, the roles of CO in host-gut microbiome communication are examined through a discussion of (1) host production and function of CO, (2) available CO donors as research tools, (3) CO production from diet and bacterial sources, (4) effect of CO on bacteria including CO sensing, and (5) gut microbiome production of CO. There is a large amount of literature suggesting the "messenger" role of CO in host-gut microbiome communication. However, much more work is needed to begin achieving a systematic understanding of this issue.

Medicinal Plants as Sources of Active Molecules Against COVID-19

The Severe Acute Respiratory Syndrome-related Coronavirus 2 (SARS-CoV-2) or novel coronavirus (COVID-19) infection has been declared world pandemic causing a worrisome number of deaths, especially among vulnerable citizens, in 209 countries around the world. Although several therapeutic molecules are being tested, no effective vaccines or specific treatments have been developed. Since the COVID-19 outbreak, different traditional herbal medicines with promising results have been used alone or in combination with conventional drugs to treat infected patients. Here, we review the recent findings regarding the use of natural products to prevent or treat COVID-19 infection. Furthermore, the mechanisms responsible for this preventive or therapeutic effect are discussed. We conducted literature research using PubMed, Google Scholar, Scopus, and WHO website. Dissertations and theses were not considered. Only the situation reports edited by the WHO were included. The different herbal products (extracts) and purified molecules may exert their anti-SARS-CoV-2 actions by direct inhibition of the virus replication or entry. Interestingly, some products may block the ACE-2 receptor or the serine protease TMPRRS2 required by SARS-CoV-2 to infect human cells. In addition, natural products were shown to inhibit the SARS-CoV-2 life-cycle related proteins such as papain-like or chymotrypsin-like proteases. In conclusion, we suggest that natural products could be used alone or in combination as alternative medicines to treat/prevent COVID-19 infection. Moreover, their structures may offer clues for the development of anti-SARS-CoV-2 drugs.

Anti-Cancer Potential of Cannabinoids, Terpenes, and Flavonoids Present in Cannabis

In recent years, and even more since its legalization in several jurisdictions, cannabis and the endocannabinoid system have received an increasing amount of interest related to their potential exploitation in clinical settings. Cannabinoids have been suggested and shown to be effective in the treatment of various conditions. In cancer, the endocannabinoid system is altered in numerous types of tumours and can relate to cancer prognosis and disease outcome. Additionally, cannabinoids display anticancer effects in several models by suppressing the proliferation, migration and/or invasion of cancer cells, as well as tumour angiogenesis. However, the therapeutic use of cannabinoids is currently limited to the treatment of symptoms and pain associated with chemotherapy, while their potential use as cytotoxic drugs in chemotherapy still requires validation in patients. Along with cannabinoids, cannabis contains several other compounds that have also been shown to exert anti-tumorigenic actions. The potential anti-cancer effects of cannabinoids, terpenes and flavonoids, present in cannabis, are explored in this literature review.

Kaempferol: A Key Emphasis to Its Anticancer Potential

A marked decrease in human cancers, including breast cancer, bone cancer, and cervical cancer, has been linked to the consumption of vegetable and fruit, and the corresponding chemoprotective effect has been associated with the presence of several active molecules, such as kaempferol. Kaempferol is a major flavonoid aglycone found in many natural products, such as beans, bee pollen, broccoli, cabbage, capers, cauliflower, chia seeds, chives, cumin, moringa leaves, endive, fennel, and garlic. Kaempferol displays several pharmacological properties, among them antimicrobial, anti-inflammatory, antioxidant, antitumor, cardioprotective, neuroprotective, and antidiabetic activities, and is being applied in cancer chemotherapy. Specifically, kaempferol-rich food has been linked to a decrease in the risk of developing some types of cancers, including skin, liver, and colon. The mechanisms of action include apoptosis, cell cycle arrest at the G2/M phase, downregulation of epithelial-mesenchymal transition (EMT)-related markers, and phosphoinositide 3-kinase/protein kinase B signaling pathways. In this sense, this article reviews data from experimental studies that investigated the links between kaempferol and kaempferol-rich food intake and cancer prevention. Even though growing evidence supports the use of kaempferol for cancer prevention, further preclinical and clinical investigations using kaempferol or kaempferol-rich foods are of pivotal importance before any public health recommendation or formulation using kaempferol.