In vitro cytotoxic activity of Baccharis dracunculifolia and propolis against HEp-2 cells

In Vitro and In Vivo Investigation on the Effectiveness of Alginate-Based Gastric Mucosal Protective Gel

Objective

To investigate the feasibility and effectiveness of an alginate-based gastric mucosal protective gel on the gastric ulcer.

Methods

(1) In the physical protection model, after GES-1 cell attachment add the gel to transwell chamber, add different concentrations of HCl to the gel. Absorbance was measured to assess proliferation and images of the cells migrating into the wound were taken; then the migration rate of the cells was quantified by comparing images. (2) In the gastric ulcer model, excise the gastric mucosal of SD rats; the gel and fixative were applied on the artificial ulcer immediately. Dissect rats after 10 days, and calculate the wound healing rate and analyzed histology changes.

Results

The effect of hydrochloric acid on cells in the lower layer was significantly reduced after the use of gastric mucosal protection gel. The protective gel had an isolation effect on different concentrations of acid. A number of GES-1 were significantly higher than those in the control group at 24 h to 72 h (P < 0.01). The migration was observed compared with the control group. The average healing rate of ulcer in the gel group was about 50%, and the control group was about 30%. Inflammation occurred in all wound regions after ten days. In the gel group, inflammatory infiltration depth was lower than that of the control, and part of SD rats' new muscle layer appeared without inflammatory infiltration. The connective tissue proliferation promoted tissue repair. In the control group, necrosis marginal, mucosal hyperplasia, marginal lymphocyte aggregation, and bleeding were observed.

Conclusion

This novel gel mainly has an isolating and shielding effect to prevent the wound from being exposed to gastric acid for a long time, and it can reduce the inflammatory reaction on the wounds to promote the healing of the ulcer. The gastric mucosal protective gel cannot only promote the speed of wound healing but also improve the quality of wound healing.

Effects of Baccharin Isolated from Brazilian Green Propolis on Adipocyte Differentiation and Hyperglycemia in ob/ob Diabetic Mice

Propolis is a honeybee product with various biological activities, including antidiabetic effects. We previously reported that artepillin C, a prenylated cinnamic acid derivative isolated from Brazilian green propolis, acts as a peroxisome proliferator-activated receptor γ (PPARγ) ligand and promotes adipocyte differentiation. In this study, we examined the effect of baccharin, another major component of Brazilian green propolis, on adipocyte differentiation. The treatment of mouse 3T3-L1 preadipocytes with baccharin resulted in increased lipid accumulation, cellular triglyceride levels, glycerol-3-phosphate dehydrogenase activity, and glucose uptake. The mRNA expression levels of PPARγ and its target genes were also increased by baccharin treatment. Furthermore, baccharin enhanced PPARγ-dependent luciferase activity, suggesting that baccharin promotes adipocyte differentiation via PPARγ activation. In diabetic ob/ob mice, intraperitoneal administration of 50 mg/kg baccharin significantly improved blood glucose levels. Our results suggest that baccharin has a hypoglycemic effect on glucose metabolic disorders, such as type 2 diabetes mellitus.

Brazilian essential oils as source for the discovery of new anti-COVID-19 drug: a review guided by in silico study

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in China and its spread worldwide has become one of the biggest health problem due to the lack of knowledge about an effective chemotherapy. Based on the current reality of the SARS-CoV-2 pandemic, this study aimed to make a review literature about potential anti-coronavirus natural compounds guided by an in silico study. In the first step, essential oils from native species found in the Brazilian herbal medicine market and Brazilian species that have already shown antiviral potential were used as source for the literature search and compounds selection. Among these compounds, 184 showed high antiviral potential against rhinovirus or picornavirus by quantitative structure-activity relationship analysis. (E)-α-atlantone; 14-hydroxy-α-muurolene; allo-aromadendrene epoxide; amorpha-4,9-dien-2-ol; aristochene; azulenol; germacrene A; guaia-6,9-diene; hedycaryol; humulene epoxide II; α-amorphene; α-cadinene; α-calacorene and α-muurolene showed by a molecular docking study the best result for four target proteins that are essential for SARS-CoV-2 lifecycle. In addition, other parameters obtained for the selected compounds indicated low toxicity and showed good probability to achieve cell permeability and be used as a drug. These results guided the second literature search which included other species in addition to native Brazilian plants. The majority presence of any of these compounds was reported for essential oils from 45 species. In view of the few studies relating essential oils and antiviral activity, this review is important for future assays against the new coronavirus.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11101-021-09754-4.

Effect of light, oxygen and temperature on the stability of artepillin C and p-coumaric acid from Brazilian green propolis

Brazilian Green Propolis (BGP) is an important bee product, which displays important biological activities, making it valuable in the international market. The major prenylated phenolic compound in BPG is (E)-artepillin C, along with its precursor (E)-p-coumaric acid, both contributing to the biological effects of BGP. Taking that into account, it was evaluated the effect of light, temperature and air oxygen in their content to establish the best storage and transport conditions for crude BGP and the pure compounds. For that, (E)-artepillin C and (E)-p-coumaric acid were initially submitted to degradation for five days under sunlight and high temperature (50 °C), furnishing three major (E)-Artepillin C isomers and one from (E)-p-coumaric acid. Then, it was developed and validated a Reverse Phase High Performance Liquid Chromatography (RP-HPLC) method for quantifying these compounds in crude BGP and in its extracts. In the stability studies, it was used a Full Factorial and Central Composite Design to establish the desirable storage conditions. (E)-Artepillin C, both pure and in BGP should be kept protected from light and storage below -2.5 °C. (E)-p-Coumaric acid can be stored at room temperature. Therefore, the best storage and transport conditions to keep the content of both compounds in BGP are protection from light at low temperatures.

Chemical analysis and antiviral activity evaluation of Baccharis anomala

The chemical composition and antiviral activity of aqueous extract from Baccharis anomala was studied by bioactivity-guided fractionation. Ethanol precipitation and fractionation by molecular permeation allowed the separation of the anti-herpes simplex virus 1 (HSV-1) active fraction from aqueous extract (Fraction B). Natural Product Reagent A, FeCl₃ and thin-layer chromatography indicated the presence of phenolic compounds in the aqueous extract. Fraction B showed pronounced antiviral activity when tested with HSV-1 strains VR733/ATCC and Acyclovir-resistant 29-R, displaying virucidal but not virustatic activity.

Assessment in vitro of the genotoxicity, antigenotoxicity and antioxidant of Ceratonia siliqua L. extracts in murine leukaemia cells L1210 by comet assay

Genotoxicity of Ceratonia siliqua extracts, was investigated by assessing their capacity to induce nucleus DNA degradation of murine leukaemia cells L1210, using the "Comet assay". The ability of total oligomer flavonoids (TOF) and aqueous extracts to protect cell DNA against oxidative stress induced by H2O2, was performed by pre- co or post-treatment of cells with the before mentioned extracts for different periods preceding exposure to H2O2 stress. No significant genotoxic effect was detected at different exposure times, except at the lowest concentration of TOF extract (16.25 μg/ml). It appears that extracts decreased DNA damage, induced by H2O2. Both of TOF and aqueous extracts exhibited cellular antioxidant capacity, with EC50 values of respectively <16.25 and < 35 μg/ml, as well as, a protective capacity against lipidperoxidation inducing using L1210 cells line as a cellular model. MDA inhibition percentages reached 88.43% and 90.52% with respectively 35.5 μg/ml of TOF extract and 70 μg/ml of aqueous extract. Antioxidant properties of carob leaf extracts revealed by our study make a good antioxidant protection and thus a good candidate as food addition component.

Biological activity of terpene compounds produced by biotechnological methods

CONTEXT

Biotransformation systems are profitable tools for structural modification of bioactive natural compounds into valuable biologically active terpenoids.

OBJECTIVE

This study determines the biological effect of (R)-(+)-limonene and (-)-α-pinene, and their oxygenated derivatives, (a) perillyl alcohol and (S)-(+)- and (R)-(-)-carvone enantiomers and (b) linalool, trans-verbenol and verbenone, respectively, on human colon tumour cells and normal colonic epithelium.

MATERIALS AND METHODS

Biotransformation procedures and in vitro cell culture tests were used in this work. Cells were incubated for 24 h with terpenes at concentrations of 5-500 μg/mL for NR, MTT, DPPH, and NO assays. IL-6 was determined by ELISA with/without 2 h pre-activation with 10 μg/mL LPS.

RESULTS

trans-Verbenol and perillyl alcohol, obtained via biotransformation, produced in vitro effect against tumour cells at lower concentrations (IC50 value = 77.8 and 98.8 μg/mL, respectively) than their monoterpene precursors, (R)-(+)-limonene (IC50 value = 171.4 μg/mL) and (-)-α-pinene (IC50 value = 206.3 μg/mL). They also showed lower cytotoxicity against normal cells (IC50 > 500 and > 200 μg/mL, respectively). (S)-(+)-Carvone was 59.4% and 27.1% more toxic to tumour and normal cells, respectively, than the (R)-(-)-enantiomer. (R)-(+)-limonene derivatives decreased IL-6 production from normal cells in media with or without LPS (30.2% and 13.9%, respectively), while (-)-α-pinene derivatives induced IL-6 (verbenone had the strongest effect, 60.2% and 29.1% above control, respectively). None of the terpenes had antioxidative activity below 500 μg/mL.

DISCUSSION AND CONCLUSIONS

Bioactivity against tumour cells decreased in the following order: alcohols > ketones > hydrocarbons. (R)-(+)-limonene, (-)-α-pinene, and their derivatives expressed diverse activity towards normal and tumour cells with noticeable enantiomeric differences.

Propolis and its constituent caffeic acid suppress LPS-stimulated pro-inflammatory response by blocking NF-κB and MAPK activation in macrophages

ETHNOPHARMACOLOGICAL RELEVANCE

Propolis is a bee product with numerous biological and pharmacological properties, such as immunomodulatory and anti-inflammatory activities. It has been used in folk medicine as a healthy drink and in food to improve health and prevent inflammatory diseases. However, little is known about its mechanism of action. Thus, the goal of this study was to verify the antioxidant activity and to explore the anti-inflammatory properties of propolis by addressing its intracellular mechanism of action. Caffeic acid was investigated as a possible compound responsible for propolis action.

MATERIALS AND METHODS

The antioxidant properties of propolis and caffeic acid were evaluated by using the 2,2-Diphenyl-1-picrylhydrazyl free radical (DPPH) scavenging method. To analyze the anti-inflammatory activity, Raw 264.7 macrophages were treated with different concentrations of propolis or caffeic acid, and nitric oxide (NO) production, a strong pro-inflammatory mediator, was evaluated by the Griess reaction. The concentrations of propolis and caffeic acid that inhibited NO production were evaluated on intracellular signaling pathways triggered during inflammation, namely p38 mitogen-activated protein kinase (MAPK), c-jun NH2-terminal kinase (JNK1/2), the transcription nuclear factor (NF)-κB and extracellular signal-regulated kinase (ERK1/2), through Western blot using specific antibodies. A possible effect of propolis on the cytotoxicity of hepatocytes was also evaluated, since this product can be used in human diets.

RESULTS

Caffeic acid showed a higher antioxidant activity than propolis extract. Propolis and caffeic acid inhibited NO production in macrophages, at concentrations without cytotoxicity. Furthermore, both propolis and caffeic acid suppressed LPS-induced signaling pathways, namely p38 MAPK, JNK1/2 and NF-κB. ERK1/2 was not affected by propolis extract and caffeic acid. In addition, propolis and caffeic acid did not induce hepatotoxicity at concentrations with strong anti-inflammatory potential.

CONCLUSIONS

Propolis exerted an antioxidant and anti-inflammatory action and caffeic acid may be involved in its inhibitory effects on NO production and intracellular signaling cascades, suggesting its use as a natural source of safe anti-inflammatory drugs.

The effect of propolis on CCL5 and IFN-γ expression by peripheral blood mononuclear cells from leishmaniasis patients

Objectives

Mucocutaneous leishmaniasis is associated with a strong Th1 immune response to Leishmania, which modulates chemokines and their receptors expression, affecting their migratory capacity. There are no antileishmanial vaccines available and chemotherapy still relies on the potentially toxic pentavalent antimonials. Propolis is a bee product with immunomodulatory and antiparasite activities, and researchers have been attracted to its potential for the development of new drugs. This work investigated the effects of propolis on CCL5 and IFN-γ expression by peripheral blood mononuclear cells (PBMC) in order to evaluate a possible immunomodulatory action of propolis in patients with leishmaniasis compared to healthy control subjects.

Methods

PBMC were incubated in the absence or presence of propolis and the evaluation of a possible cytotoxicity of propolis was carried out using MTT assay. The expression level of CCL5 and IFN-γ was determined by real-time PCR.

Key findings

Our data indicated that propolis modulates the immune response of leishmaniasis patients in vitro, affecting CCL5 and IFN-γ expression by PBMC.

Conclusions

Data suggested that propolis drives an anti-inflammatory response depending on concentration. Although propolis is a potential source of new and selective drugs for the treatment of leishmaniasis, its usefulness in the therapeutics should be further investigated.

Cytotoxic constituents of propolis inducing anticancer effects: a review

Objectives

Propolis is a honeybee product used extensively in traditional medicine for its antioxidant, anti-inflammatory, immunomodulatory and anticancer effects. Propolis exhibits a broad spectrum of biological activities because it is a complex mixture of natural substances. In this review, the antitumour effects of propolis extracts and its constituents (e.g. flavonoids, terpenes and caffeic acid phenethyl ester) are discussed.

Key findings

The effect of propolis on experimental carcinogenesis is discussed, as well as its possible mechanisms of action against tumours, involving apoptosis, cell cycle arrest and interference on metabolic pathways. Propolis seems to be efficient against different tumour cells both in vitro and in vivo, which suggests its potential in the development of new anticancer drugs.

Summary

Propolis extracts may be important economically and would allow a relatively inexpensive cancer treatment. Preclinical investigations are needed to further elucidate the benefits of propolis and its antitumour properties.

Propolis protects against 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced toxicity in rat hepatocytes

The present experiment was undertaken to determine the effectiveness of propolis in alleviating the toxicity of TCDD on cultured primary rat hepatocytes. Propolis (25, 50 and 100 μM) was added to plain culture or simultaneously with TCDD (5 and 10 μM). The hepatocytes were treated with TCDD and propolis for 48 h. Then cell viability was detected by [3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide] (MTT) assay and lactate dehydrogenase (LDH) release, while total antioxidant capacity (TAC) and total oxidative stress (TOS) levels were determined to evaluate the oxidative injury. The DNA damage was also analyzed by liver micronucleus assay (LMN) and 8-oxo-2-deoxyguanosine (8-OH-dG). The results of MTT and LDH assays showed that TCDD decreased cell viability. TCDD also increased TOS level and decreased TAC level in rat hepatocytes. On the basis of increasing doses, the TCDD caused significant increases of micronucleated hepatocytes (MNHEPs) and 8-OH-dG levels as compared to control culture. In cultures treated with propolis alone, cell viability and TOS level were not affected, while the level of TAC was significantly increased in dose-dependent fashion. The presence of propolis with TCDD modulated its toxic effects on primary hepatocytes cultures. Noteworthy, propolis has a protective effect against TCDD-mediated DNA damages.

Analytical methods applied to diverse types of Brazilian propolis

Propolis is a bee product, composed mainly of plant resins and beeswax, therefore its chemical composition varies due to the geographic and plant origins of these resins, as well as the species of bee. Brazil is an important supplier of propolis on the world market and, although green colored propolis from the southeast is the most known and studied, several other types of propolis from Apis mellifera and native stingless bees (also called cerumen) can be found. Propolis is usually consumed as an extract, so the type of solvent and extractive procedures employed further affect its composition. Methods used for the extraction; analysis the percentage of resins, wax and insoluble material in crude propolis; determination of phenolic, flavonoid, amino acid and heavy metal contents are reviewed herein. Different chromatographic methods applied to the separation, identification and quantification of Brazilian propolis components and their relative strengths are discussed; as well as direct insertion mass spectrometry fingerprinting.Propolis has been used as a popular remedy for several centuries for a wide array of ailments. Its antimicrobial properties, present in propolis from different origins, have been extensively studied. But, more recently, anti-parasitic, anti-viral/immune stimulating, healing, anti-tumor, anti-inflammatory, antioxidant and analgesic activities of diverse types of Brazilian propolis have been evaluated. The most common methods employed and overviews of their relative results are presented.

Biological activities of Portuguese propolis: protection against free radical-induced erythrocyte damage and inhibition of human renal cancer cell growth in vitro

This study reports for the first time the biological properties of Portuguese propolis. The antioxidant potential of propolis samples from Bornes (Northeast) and Fundão (Centre) regions of Portugal was evaluated by their ability to inhibit the 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced oxidative hemolysis and lipid peroxidation in human erythrocytes. Bornes and Fundão propolis strongly protected the erythrocyte membrane from hemolysis (IC(50) of 6.3±0.7 and 10.4±2.7 μg/ml, respectively), in a time- and concentration-dependent manner. This effect was found to be significantly higher than that presented by ascorbic acid (IC(50) of 31.0±5.6 μg/ml). In addition, human erythrocytes treated with propolis extracts showed concentration-dependent decrease in levels of malondialdehyde, a breakdown product of lipid peroxidation. Propolis extracts were also assayed for their anticancer properties on human renal cell carcinoma (RCC). Primary cultures of normal and cancerous renal cells derived from RCC patients, in addition to A-498 cell line, were treated with propolis extracts (0-100 μg/ml). Cytotoxic and antiproliferative effects were determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Propolis extracts exhibited selective toxicity against malignant cells compared to normal cells. In vitro RCC growth was strongly inhibited by Bornes and Fundão propolis in a concentration-dependent manner. Our results indicate that Portuguese propolis constitutes an excellent source of effective natural antioxidant and chemopreventive agents.

Anti-poliovirus activity of Baccharis dracunculifolia and propolis by cell viability determination and real-time PCR

Aims:  The aim of this work was to evaluate the antiviral activities of Baccharis dracunculifolia (extract and essential oil), propolis and some isolated compounds (caffeic and cinnamic acids) against poliovirus type 1 (PV1) replication in HEp‐2 cells.

Method:  Three different protocols (pre‐, simultaneous and post‐treatments) were used to verify the effect of addition time of the variables on PV1 replication by crystal violet method and relative viral RNA quantification by real‐time PCR for analysing in which step of virus replication the variables could interfere.

Conclusions:  Data revealed that the B. dracunculifolia showed the best antiviral activity percentage in the simultaneous treatment, as well as lower relative viral quantification by real‐time PCR. Variables might block partially the viral entry within cells, affect the steps of viral cycle replication into cells, or lead to RNA degradation before the virus entry into cells or after their release to the supernatant.

Significance and Impact of the Study: Baccharis dracunculifolia is the most important botanical source of the south‐eastern Brazilian propolis, and its potential for the development of new phytotherapeutic medicines has been investigated. Propolis is commonly used for its antimicrobial and immunomodulatory activities. Nevertheless, B. dracunculifolia and propolis effects on PV1 have not been investigated yet.