Hepatoprotective and anti-Helicobacter pylori activities of constituents from Brazilian propolis

Antioxidant Activity, Total Phenolic Content, and Volatile Component Profiles of Propolis From Eight Turkish Regions

This study aimed to evaluate the volatile component profiles and antioxidant activities of propolis samples collected from eight regions of Türkiye. The total phenolic content of propolis samples was found to vary between 5333 and 36967 mg GAE/100 g. 2,2-Diphenyl-1-picrylhydrazyl radical scavenging activity of the samples varied from 10.9% to 92.2%, while 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical scavenging activity varied from 193.8 to 1026.0 µmol Trolox/g. Six of the eight samples exhibited higher antioxidant activities than butylated hydroxytoluene. The predominant volatile components identified in the majority of the propolis samples were α-pinene, limonene, bornyl acetate, caryophyllene, α-humulene, δ-cadinene, isopentyl acetate, acetic acid, nonanal, m-cymene, and pinocarvone. Principal component analysis (PCA) and hierarchical cluster analyses were applied to the GC-MS data to investigate the trends and clustering in the propolis samples. The propolis samples were divided into four groups using cluster analysis. In the PCA, the first two factors represented 56.39% of the variance. These findings revealed that Turkish propolis has significant antioxidant properties and also contains important volatile compounds. Consequently, Turkish propolis could be considered a potential candidate for incorporation into pharmaceutical and food products.

Composition and bioactivity of propolis derived from New Zealand native forest

New Zealand's unique indigenous flora has evolved due to its geographical isolation in the Southern Hemisphere. In the 250 years, since European colonisation commenced, much indigenous flora has been replaced by plants largely of Northern Hemisphere origin including poplar species and pine. There are however still a few large areas of principally native flora. The honeybee (Apis mellifera) was introduced to New Zealand in 1839, so has no evolutionary link to the New Zealand indigenous flora. New Zealand propolis from areas in which honeybees have access to poplar and other Northern Hemisphere species is similar in chemical profile to Northern Hemisphere propolis. However, when honeybees were placed in an extensive area of native flora, Te Urewera in the North Island,the chemical profile of propolis produced was vastly different. This "endemic" propolis was characterised by the presence of diterpenoids in contrast to the flavonoids found in poplar-type propolis. These diterpenoids, isocupressic acid, acetyl isocupressic acid, manool, torulosal, communic acid and ferruginol, were characterised by GC-MS and by NMR spectroscopy of the isolated compounds. The "endemic" propolis has commonality with propolis of the Mediterranean-type as well as some Brazilian propolis. Investigation of the bioactivity of a sample of the "endemic" propolis revealed good antioxidant behaviour with a TEAC of 1481 mgtrolox g-1, dose-dependent inhibition of mitochondrial dehydrogenase activity, inhibition of superoxide production with an IC50 of 262 μg mL-1 and inhibition of methicillin resistant and methicillin sensitive S. aureus. Much of this bioactivity can be attributed to the presence of the diterpenoids.

Brazilian Stingless Bee Geopropolis Exhibit Antioxidant Properties and Anticancer Potential Against Hepatocellular Carcinoma Cells

Hepatocellular carcinoma (HCC) is the third most common cancer in terms of mortality and the sixth in incidence worldwide. Treatment varies by tumor stage, but low survival rates are common across all stages. Due to these poor outcomes, there is a critical need for new treatment options and lead compounds, prompting an active search. Geopropolis has been identified as a source of bioactive compounds with various pharmacological activities, including anticancer effects against different types of cancer. Since stingless bees may be selective for native botanical species, the geopropolis they produce can have an unusual chemical profile. In this study, we report the antioxidant properties and anticancer potential of geopropolis extracts produced by Melipona bicolor, M. marginata, and M. mondury using 2D- and 3D- cell culture models. The chemical profile of these samples using UPLC-QTOF HRMS/MS indicated ferreirin and dihydrokaempferide as the main flavonoids, along with cupressic acid and 15-acetoxyisocupressic acid as the most abundant diterpenoids. Interestingly, artepillin C, a main component of green propolis, was also detected. The geopropolis extracts showed good cell viability inhibition and selectivity indices in comparison to cisplatin used as an HCC treatment option. The antioxidant capacity of the geopropolis extracts was high and correlated with the cytotoxic effect against the HCC cells. Investigations into the mechanisms show the ability of the extracts to induce apoptosis and suppress the clonogenic potential of these cell lines. We also observed an inhibition of spheroid formation, viability, and morphology alterations. This is the first time the effects of geopropolis are described in a panel of HCC cell lines.

Hydrogel Containing Propolis: Physical Characterization and Evaluation of Biological Activities for Potential Use in the Treatment of Skin Lesions

BACKGROUND

Skin injury affects the integrity of the skin structure and induces the wound healing process, which is defined by a well-coordinated series of cellular and molecular reactions that aim to recover or replace the injured tissue. Hydrogels are a group of promising biomaterials that are able to incorporate active ingredients for use as dressings. This study aimed to synthesize hydrogels with and without propolis extract and evaluate their physical characteristics and biological activities in vitro for potential use as active dressings in the treatment of skin lesions.

METHODS

The antifungal [Candida albicans (C. albicans) and Candida tropicalis (C. tropicalis)] and antibacterial [Staphylococcus aureus (S. aureus), Pseudomonas aeruginosas (P. aeruginosas) and Escherichia coli (E. coli)] activity was assessed by the microdilution method in plates and antioxidant potential by the reduction of the phosphomolybdate complex.

RESULTS

The hydrogels showed good water absorption capacity, high solubility, and high gel fraction, as well as good porosity, water retention, and vapor transmission rates. They revealed a totally amorphous structure. The extract and the hydrogels containing the propolis extract (1.0% and 2.5%) did not inhibit fungal growth. However, they showed antibacterial activity against strains of S. aureus and P. aeruginosas. Regarding the E. coli strain, only the extract inhibited its growth. It showed good antioxidant activity by the evaluation method used.

CONCLUSIONS

Therefore, the hydrogels containing propolis extract can be a promising alternative with antibacterial and antioxidant action for use as dressings for the treatment of skin lesions.

Identification of volatile compounds and evaluation of certain phytochemical properties of Turkish propolis

The purpose of this study was to assess volatile component profiles and the antioxidant activity of propolis samples from eight different locations in Türkiye. α-Pinene, β-pinene, 3-carene, limonene, 2-acetylfuran, benzaldehyde, acetic acid, benzoic acid, longifolene, isopentyl acetate, m-cymene, styrene, and δ-cadinene were the most common volatile components found in the most of propolis samples. Principal component analysis (PCA) and hierarchical cluster analysis were performed on the gas chromatography-mass spectrometry (GC-MS) data to identify trends and clusters in the propolis samples. As a result of the PCA, the common components in all propolis were m-cymene, decanal, α-pinene, limonene, pinocarvone, benzaldehyde, and butanoic acid. The samples had 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) inhibition activity ranging from 19.2% to 92.5% and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) values ranging from 480 to 1370 μM trolox/g extract. The total phenolic content (TPC) ranged from 10,900 to 34,033 mg GAE/100 g. Compared with butylated hydroxytoluene (BHT) (control), all but one of the propolis samples exhibited higher DPPH activity. In addition, ABTS levels of propolis extracts were higher than those of BHT. These results unequivocally show that Turkish propolis has remarkable antioxidant qualities, which makes it a viable option for addition to food and medicine products.

Natural antioxidants from some fruits, seeds, foods, natural products, and associated health benefits: An update

Antioxidants are compounds that inhibit the oxidation of other molecules and protect the body from the effects of free radicals, produced either by normal cell metabolism or as an effect of pollution and exposure to other external factors and are responsible for premature aging and play a role in cardiovascular disease. degenerative diseases such as cataracts, Alzheimer's disease, and cancer. While many antioxidants are found in nature, others are obtained in synthetic form and reduce oxidative stress in organisms. This review highlights the pharmacological relevance of antioxidants in fruits, plants, and other natural sources and their beneficial effect on human health through the analysis and in-depth discussion of studies that included phytochemistry and their pharmacological effects. The information obtained for this review was collected from several scientific databases (ScienceDirect, TRIP database, PubMed/Medline, Scopus, Web of Science), professional websites, and traditional medicine books. Current pharmacological studies and evidence have shown that the various natural antioxidants present in some fruits, seeds, foods, and natural products have different health-promoting effects. Adopting functional foods with high antioxidant potential will improve the effective and affordable management of free radical diseases while avoiding the toxicities and unwanted side effects caused by conventional medication.

Anti-Inflammatory Effect of Korean Propolis on Helicobacter pylori-Infected Gastric Mucosal Injury Mice Model

Propolis, a natural resinous substance obtained from a variety of buds and plants, has been reported to possess various biological functions. Several recent studies have demonstrated the inhibitory effects of propolis on the growth of Helicobacter pylori (H. pylori) in vitro; however, current research efforts on Korean propolis (KP) remain insufficient especially in vivo. Our study aims to investigate the anti-inflammatory effect and molecular mechanism of KP on mouse gastric mucosa during H. pylori infection. We examined an in vivo H. pylori-induced gastric mucosal injury mice model. We found that KP inhibited the growth of H. pylori and attenuated the expression of H. pylori virulence factors such as cytotoxin-associated gene A, encoding urease A subunit, surface antigen gene and neutrophil-activating protein A. Moreover, KP reduced both gross lesions and pathological scores in H. pylori-challenged mice. In addition, KP markedly restrained the production of pro-inflammatory cytokines and nitric oxide levels compared with an untreated H. pylori-infected group. In particular, we found that KP repressed the phosphorylation of IκBα and NF-κB p65 subunit, and subsequently suppressed their downstream target genes. Taken together, these findings demonstrate the beneficial effects of KP on inflammation through the inhibition of NF-κB signaling as well as inhibition of H. pylori growth in a mouse model infected with H. pylori. This suggests the potential application of KP as a natural supplement for patient’s suffering from gastric mucosal injury caused by H. pylori infection.

From propolis to nanopropolis: An exemplary journey and a paradigm shift of a resinous substance produced by bees

Propolis, a natural resinous mixture produced by honey bees is poised with diverse biological activities. Owing to the presence of flavonoids, phenolic acids, terpenes, and sesquiterpenes, propolis has garnered versatile applications in pharmaceutical industry. The biopharmaceutical issues associated with propolis often beset its use as being too hydrophobic in nature; it is not absorbed in the body well. To combat the problem, various nanotechnological approaches for the development of novel drug delivery systems are generally applied to improve its bioavailability. This paradigm shift and transition of conventional propolis to nanopropolis are evident from the literature wherein a multitude of studies are available on nanopropolis with improved bioavailability profile. These approaches include preparation of gold nanoparticles, silver nanoparticles, magnetic nanoparticles, liposomes, liquid crystalline formulations, solid lipid nanoparticles, mesoporous silica nanoparticles, etc. Nanopropolis has further been explored to assess the potential benefits of propolis for the development of futuristic useful products such as sunscreens, creams, mouthwashes, toothpastes, and nutritional supplements with improved solubility, bioavailability, and penetration profiles. However, more high-quality clinical studies assessing the effects of propolis either alone or in combination with synthetic drugs as well as natural products are warranted and its safety needs to be firmly established.

Propolis: Properties and composition, health benefits and applications in fish nutrition

Propolis is a viscous, waxy, resinous substance that is produced from the exudates of flowers and buds by the action of salivary enzymes of honey bees. Propolis may differ in color (brown, red or green), with color being influenced by the chemical composition and age of the product. Propolis has a special distinctive odor owing to the high concentration of volatile essential oils. It is composed of 5% pollen grains, 10% essential and aromatic oils, 30% wax, 50% resin and balsams, and other minor trace substances. Natural propolis products may be useful for a range of applications in aquaculture systems instead of relying on the application of synthetic compounds to manage many ailments that affect business profitability. It has been reported in several studies that propolis enhances performance, economics, immunity response and disease resistance in different fish species. This present review discusses the functional actions of propolis and the prospects of its use as an antimicrobial, antioxidant, immune-modulatory, antiseptic, antiparasitic, anti-inflammatory and food additive in aquaculture production. In summary, propolis could be a natural supplement that has the potential to improve fish health status and immunity thereby enhancing growth and productivity of the fish industry as well as economic efficiency.

Epigallocatechin Gallate with Potent Anti-Helicobacter pylori Activity Binds Efficiently to Its Histone-like DNA Binding Protein

Helicobacter pylori (H. pylori)-a human gastric pathogen-forms a major risk factor for the development of various gastric pathologies such as chronic inflammatory gastritis, peptic ulcer, lymphomas of mucosa-associated lymphoid tissues, and gastric carcinoma. The complete eradication of infection is the primary objective of treating any H. pylori-associated gastric condition. However, declining eradication efficiencies, off-target effects, and patient noncompliance to prolong and broad-spectrum antibiotic treatments has spurred the clinical interest to search for alternative effective and safer therapeutic options. As natural compounds are safe and privileged with high levels of antibacterial-activity, previous studies have tested and reported a plethora of such compounds with potential in vitro/in vivo anti-H. pylori activity. However, the mode of action of majority of these natural compounds is unclear. The present study has been envisaged to compile the information of various such natural compounds and to evaluate their binding with histone-like DNA-binding proteins of H. pylori (referred here as Hup) using in silico molecular docking-based virtual screening experiments. Hup-being a major nucleoid-associated protein expressed by H. pylori-plays a strategic role in its survival and persistent colonization under hostile stress conditions. The ligand with highest binding energy with Hup-that is, epigallocatechin-(-)gallate (EGCG)-was rationally selected for further computational and experimental testing. The best docking poses of EGCG with Hup were first evaluated for their solution stability using long run molecular dynamics simulations and then using fluorescence and nuclear magnetic resonance titration experiments which demonstrated that the binding of EGCG with Hup is fairly strong (the resultant apparent dissociation constant (k _D) values were equal to 2.61 and 3.29 ± 0.42 μM, respectively).

Plant Sources Responsible for the Chemical Composition and Main Bioactive Properties of Poplar-Type Propolis

Propolis is a resinous mixture, made by the honeybees from substances collected from tree or other plant buds, plant exudates, or resins found in the stem, branches, or leaves of different plants. The geographical origin of propolis is given by plant sources from respective areas. Different studies have classified this bee product according to the vegetal material from the same areas. Poplar-type propolis has the widest spread in the world, in the temperate zones from Europe, Asia, or North America. The name is given by the main plant source from where the bees are collecting the resins, although other vegetal sources are present in the mentioned areas. Different Pinus spp., Prunus spp., Acacia spp. and also Betula pendula, Aesculus hippocastanum, and Salix alba are important sources of resins for "poplar-type" propolis. The aim of this review is to identify the vegetal material's chemical composition and activities of plant resins and balms used by the bees to produce poplar-type propolis and to compare it with the final product from similar geographical regions. The relevance of this review is to find the similarities between the chemical composition and properties of plant sources and propolis. The latest determination methods of bioactive compounds from plants and propolis are also reviewed.

Artepillin C: A comprehensive review of its chemistry, bioavailability, and pharmacological properties

Artepillin C (ARC), a prenylated derivative of p-coumaric acid, is one of the major phenolic compounds found in Brazilian green propolis (BGP) and its botanical source Baccharis dracunculifolia. Numerous studies on ARC show that its beneficial health effects correlate with the health effects of both BGP and B. dracunculifolia. Its wide range of pharmacological benefits include antioxidant, antimicrobial, anti-inflammatory, anti-diabetic, neuroprotective, gastroprotective, immunomodulatory, and anti-cancer effects. Most studies have focused on anti-oxidation, inflammation, diabetic, and cancers using both in vitro and in vivo approaches. Mechanisms underlying anti-cancer properties of ARC are apoptosis induction, cell cycle arrest, and the inhibition of p21-activated kinase 1 (PAK1), a protein characterized in many human diseases/disorders including COVID-19 infection. Therefore, further pre-clinical and clinical studies with ARC are necessary to explore its potential as intervention for a wide variety of diseases including the recent pandemic coronaviral infection. This review summarizes the comprehensive data on the pharmacological effects of ARC and could be a guideline for its future study and therapeutic usage.

Involvement of TGF-β and Autophagy Pathways in Pathogenesis of Diabetes: A Comprehensive Review on Biological and Pharmacological Insights

Despite recent advancements in clinical drugs, diabetes treatment still needs further progress. As such, ongoing research has attempted to determine the precise molecular mechanisms of the disorder. Specifically, evidence supports that several signaling pathways play pivotal roles in the development of diabetes. However, the exact molecular mechanisms of diabetes still need to be explored. This study examines exciting new hallmarks for the strict involvement of autophagy and TGF-β signaling pathways in the pathogenesis of diabetes and the design of novel therapeutic strategies. Dysregulated autophagy in pancreatic β cells due to hyperglycemia, oxidative stress, and inflammation is associated with diabetes and accompanied by dysregulated autophagy in insulin target tissues and the progression of diabetic complications. Consequently, several therapeutic agents such as adiponectin, ezetimibe, GABA tea, geniposide, liraglutide, guava extract, and vitamin D were shown to inhibit diabetes and its complications through modulation of the autophagy pathway. Another pathway, TGF-β signaling pathway, appears to play a part in the progression of diabetes, insulin resistance, and autoimmunity in both type 1 and 2 diabetes and complications in diabetes. Subsequently, drugs that target TGF-β signaling, especially naturally derived ones such as resveratrol, puerarin, curcumin, hesperidin, and silymarin, as well as Propolis, Lycopus lucidus, and Momordica charantia extracts, may become promising alternatives to current drugs in diabetes treatment. This review provides keen insights into novel therapeutic strategies for the medical care of diabetes.

Plants against Helicobacter pylori to combat resistance: An ethnopharmacological review

Worldwide, Helicobacter pylori (H. pylori) is regarded as the major etiological agent of peptic ulcer and gastric carcinoma. Claiming about 50 percent of the world population is infected with H. pylori while therapies for its eradication have failed because of many reasons including the acquired resistance against its antibiotics. Hence, the need to find new anti-H.pylori medications has become a hotspot with the urge of searching for alternative, more potent and safer inhibitors. In the recent drug technology scenario, medicinal plants are suggested as repositories for novel synthetic substances. Hitherto, is considered as ecofriendly, simple, more secure, easy, quick, and less toxic traditional treatment technique. This review is to highlight the anti-H. pylori medicinal plants, secondary metabolites and their mode of action with the aim of documenting such plants before they are effected by cultures and traditions that is expected as necessity.

Two clerodane diterpenes isolated from Polyalthia longifolia leaves: comparative structural features, anti-histaminic and anti-Helicobacter pylori activities

Phytochemical studies of methylene chloride soluble fraction from the 70% aqueous-alcoholic extract of Polyalthia longifolia (leaves) resulted in the isolation of two known clerodane diterpenes, namely: 16α-hydroxycleroda-3,13(14)-dien-16,15-olide (1) and (4→2)-abeo-16-hydroxy-cleroda-2,13(14)-dien-15,16-olide-3-al (2). The isolated compounds were evaluated for their anti-histaminic and anti-Helicobacter pylori activities. Compound 1 was more potent than 2 with IC₅₀ 29.7 μg/mL and 189.2 μg/mL in the anti-histaminic assay and MIC equals to 31.25 μg/mL and 125 μg/mL in the anti-H. pylori assay, as compared with diclofenac (IC₅₀ = 17.9 μg/mL) and clarithromycin (MIC = 1.95 μg/mL), respectively. The differences in their structures, as well as their activity results, indicated important characteristic features necessary for activity. It was suggested that the decalin moiety in 1 was important for both activities. On the other hand, the (4→2)-abeo migration in 2 reduced both activities. The potent activities of 1 suggest its potential application as an anti-histaminic and antimicrobial agent.

Preparation and Characterization of UV-Curable Acrylic Membranes Embedding Natural Antioxidants

We examine the behaviour of acrylic resin-based membranes containing natural anti-oxidants, such as Galla chinensis tea powder extract (TP) and Taiwanese green propolis (TGP), in different concentrations ranging between 5 and 20 wt %. Membrane morphology was investigated by means of Environmental Scanning Electron Microscopy (ESEM), while the UV-curing reaction was monitored by Fourier-Transform Infra-red (FTIR) spectroscopy. In most cases Thermogravimetric (TG), Differential Scanning Calorimetric (DSC) and Dynamo-mechanical Thermal (DMT) analyses showed that the desirable characteristics of the UV-cured acrylic resin are not substantially altered by the presence of the organic fillers. The release kinetics of polyphenols and flavonoids, determined in water for TP-containing membranes (ETx) and in ethanol/water mixture (7:3 v/v) for TGP-containing ones (EPx), was satisfactory, reaching a plateau after 24 h. Finally, preliminary antibacterial tests against S. epidermidis were performed on the membranes with higher additive amount and gave positive results for ET-type; on the contrary, no inhibitory effect was observed for the tested EP-type membranes.

Composition and functional properties of propolis (bee glue): A review

Propolis is a natural substance collected by honey bees from various plants such as, poplar, palm, pine, conifer secretions, gums, resins, mucilage and leaf buds. It is collected and brought very painstakingly by honey bees to be used for sealing cracks and crevices occurring in their hives. Originally, it as an antiseptic meant for preventing bee-hive from microbial infections along with preventing decomposition of intruders. Additionally, propolis has been used in folk medicine for centuries. The biological characteristics of propolis depend upon its chemical composition, plant sources, geographical zone and seasons. More than 300 compounds have been identified in propolis such as, phenolic compounds, aromatic acids, essential oils, waxes and amino acids. Many scientific articles are published every year in different international journals, and several groups of researchers have focused their attention on the chemical compounds and biological activity of propolis.

Physicochemical analyses, antioxidant, antibacterial, and toxicity of propolis particles produced by stingless bee Heterotrigona itama found in Brunei Darussalam

In this study, the physicochemical, antioxidant, antibacterial properties, and the toxicity of propolis particles produced by stingless bee Heterotrigona itama found in Brunei Darussalam were investigated. Propolis particles of different sizes were extracted from raw propolis using various volume fractions of ethanol in water. Spectroscopic analyses were utilized to characterize the chemical structures, functional groups, as well as absorbance and fluorescence properties. The total antioxidant capacity of propolis particles, which was assessed using DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, was found to increase with volume fraction of ethanol. The maximum antioxidant capacity was as high as 317.65 mg ascorbic acid equivalent per gram of propolis particles. All of the propolis particles showed antibacterial activity against Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). The diameters of the inhibition zone were either significantly higher or equivalent to those of two standard antibiotics (rifampicin and streptomycin), suggesting strong antibacterial activity. The toxicity studies of propolis particles against Caenorhabditis elegans revealed that they are non-toxic after 24 h exposure. Overall findings suggest that H. itama propolis particles are not only an important source of natural antioxidants that could be beneficial for human health, but they have potentials as antimicrobial against bacteria.

Helicobacter pylori and nutrition: a bidirectional communication

Helicobacter pylori (HP) is a gram-negative flagellated pathogen acid-resistant bacterium; it belongs to the order Campylobacterales that is wide spread all over the world, infecting more than 50% of the world population. HP infection is etiologically associated with non-atrophic and atrophic gastritis, peptic ulcer and with 3 to 6-fold increased relative risk for developing gastric adenocarcinoma and mucosa-associated lymphoid tissue (MA LT) lymphoma. For this reason HP is recognized by the World Health Organization as a Class I human carcinogen. In the last years a lot of studies clarified the role of this pathogen in nutrition and metabolism; particularly, it has been shown that it is able to induce malabsorption of several nutrients like iron, cobalamin, vitamin C and vitamin E, with strong consequences on nutritional status. Interesting, this bacterium is able to produce different biological effects on hormones like ghrelin and leptin controlling both appetite and growth, mostly depending on the time of acquisition of the infection and of its treatment. In this review, the authors focused their attention on nutritional effects of HP infection and particularly on the role that diet, food, plants and specific nutrients can play in its treatment, considering that HP eradication rates, with standard triple-therapy, have fallen to a low level in the last years.

Chemical Diversity and Biological Activity of African Propolis

Natural remedies have for centuries played a significant role in traditional medicine and continue to be a unique reservoir of new chemical entities in drug discovery and development research. Propolis is a natural substance, collected by bees mainly from plant resins, which has a long history of use as a folk remedy to treat a variety of ailments. The highly variable phytochemical composition of propolis is attributed to differences in plant diversity within the geographic regions from which it is collected. Despite the fact that the last five decades has seen significant advancements in the understanding of the chemistry and biological activity of propolis, a search of the literature has revealed that studies on African propolis to date are rather limited. The aim of this contribution is to report on the current body of knowledge of African propolis, with a particular emphasis on its chemistry and biological activity. As Africa is a continent with a rich flora and a vast diversity of ecosystems, there is a wide range of propolis phytochemicals that may be exploited in the development of new drug scaffolds.

Influence of Dietary Supplementation of Propolis and Bee Pollen on Liver Pathology in Broiler Chickens

Simple Summary

Today, there are increased demands for consumers to use natural products as alternative additives in broiler feeding. In this study, we evaluated the effects of propolis and bee pollen as potential new additives on liver pathology in broilers. The results of this study showed that supplementation of broilers with propolis and/or bee pollen has a strong protective effect on liver pathology. Thus, these natural agents can be used as alternative additives in modern broiler production. Such an approach will enable the production of chicken meat enriched with bioactive substances from propolis and/or bee pollen, such as flavonoids, that have been proven beneficial for human health.

Abstract

One of the major problems in intensive breeding of chickens is liver damage. The objective of this study was to determine the influence of dietary supplementation with propolis and bee pollen on liver pathology in broiler chickens. The study was conducted on 200 Ross 308 chickens equally distributed by sex that were divided into five groups. Throughout the whole study, the control group of chickens was fed with a basal diet, while the experimental groups of chickens were fed with the same diet further supplemented with propolis and bee pollen, each supplement given separately or in combination in a certain proportion. The study showed that the clusters of lymphocytes in the hepatocytes, the vacuolar degeneration and necrosis of the liver parenchyma, the bile ductule hyperplasia, and the various forms of pathological changes in the liver arteries and veins were more frequent in liver tissue samples of the control group compared to liver tissue samples of all the experimental groups (p < 0.001). The study further showed that all the previously mentioned histopathological lesions of liver tissue were always more extensive in the liver tissue samples of the control group than in the liver tissue samples of all the experimental groups (p < 0.001). The supplementation of broiler chickens with propolis and/or bee pollen has a strong protective effect on liver pathology in broiler chickens.

GC-MS analysis and hepatoprotective activity of the n-hexane extract of Acrocarpus fraxinifolius leaves against paracetamol-induced hepatotoxicity in male albino rats

CONTEXT

In Egypt, the burden of liver diseases is exceptionally high.

OBJECTIVE

To investigate the components of the n-hexane extract of Acrocarpus fraxinifolius Arn. (Leguminosae) and its hepatoprotective activity against paracetamol (APAP)-induced hepatotoxicity in rats.

MATERIAL AND METHODS

TRACE GC ultra gas chromatogaphic spectrometry was used for extract analysis. Thirty albino rats were divided into six groups (five rats in each). Group 1 was the healthy control; Groups 2 and 3 were healthy treated groups (250 and 500 mg/kg b.w. of the extract, respectively) for seven days. Group 4 was hepatotoxicity control (APAP intoxicated group). Groups 5 and 6 received APAP + extract 250 and APAP + extract 500, respectively.

RESULTS

Chromatographic analysis revealed the presence of 36 components. Major compounds were α-tocopherol (18.23%), labda-8 (20)-13-dien-15-oic acid (13.15%), lupeol (11.93%), phytol (10.95%) and squalene (7.19%). In the acute oral toxicity study, the mortality rates and behavioural signs of toxicity were zero in all groups (doses from 0 to 5 g/kg b.w. of A. fraxinifolius). LD₅₀ was found to be greater than 5 g/kg of the extract. Only the high dose (500 mg/kg b.w.) of extract significantly alleviated the liver relative weight (4.01 ± 0.06) and biomarkers, as serum aspartate aminotransferase (62.87 ± 1.41), alanine aminotransferase (46.74 ± 1.45), alkaline phosphatase (65.96 ± 0.74), lipid profiles (180.39 ± 3.51), bilirubin profiles (2.30 ± 0.06) and hepatic lipid peroxidation (114.20 ± 2.06), and increased body weight (11.58 ± 0.20), serum protein profile (11.09 ± 0.46) and hepatic total antioxidant capacity (23.78 ± 0.66) in APAP-induced hepatotoxicity in rats.

CONCLUSION

Our study proves the antihepatotoxic/antioxidant efficacies of A. fraxinifolius hexane extract.

Propolis Diterpenes as a Remarkable Bio-Source for Drug Discovery Development: A Review

Propolis is one of the complex, but valuable, bio-sources for discovering therapeutic compounds. Diterpenes are organic compounds composed of four isoprene units and are known for their biological and pharmacological characteristics, such as antibacterial, anticancer, and anti-inflammatory activities. Recently, advancements have been made in the development of antibacterial and anticancer leads from propolis-isolated diterpenes, and scrutiny of these compounds is being pursued. Thus, this review covers the progress in this arena, with a focus on the chemistry and biological activities of propolis diterpenes. It is anticipated that important information, in a comprehensive and concise manner, will be delivered here for better understanding of natural product drug discovery research.

Hepatoprotective effect of Anacyclus pyrethrum Linn. against antitubercular drug-induced hepatotoxicity in SD rats

BACKGROUND

Traditional remedies employ herbal drugs for the treatment of liver ailments and hepatoprotection. Thus, the present study was designed to evaluate the hepatoprotective effect of "extract of Anacyclus pyrethrum Linn" (APE) against antitubercular drug-induced hepatotoxicity in rats.

METHODS

Group I rats (normal control) received vehicle (1 % CMC), while group II rats (hepatotoxic control) isoniazid (INH) plus rifampicin (RIF) each 50 mg/kg/day po, for 28 days. Group III, IV and V rats were administered with APE 200, APE 400 and silymarin 100 mg/kg/day po, respectively, for 28 days. Concurrently, hepatotoxicity was tried to induce by coadministration of INH and RIF each 50 mg/kg/day po for 28 days in group III, IV and V rats. After 24 h of the last dosing, blood was obtained under light anesthesia and the rats were killed. Hepatoprotective effect was assessed by liver weight, relative liver weight and biochemical parameters such as serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), serum bilirubin, cholesterol, total protein and albumin levels.

RESULTS

Group IV rats showed significant (p<0.01) decrease in SGPT, SGOT, ALP, LDH, cholesterol, serum bilirubin, liver weight and relative liver weight Levels, while significant (p<0.01) increase in final body weight (b. wt.), total protein and albumin levels as compared to group II rats. Hepatoprotective effect of APE 400 mg/kg/day was comparable to that of silymarin 100 mg/kg/day and the hepatic marker levels were also restored. Hepatoprotective effect of APE was well supported by the histopathological results.

CONCLUSIONS

Hydroalcoholic APE root possesses hepatoprotective activity as it exhibited the protective effect against INH plus RIF-induced hepatotoxicity in rats.

Propolis Inhibits UVA-Induced Apoptosis of Human Keratinocyte HaCaT Cells by Scavenging ROS

Propolis is a resinous material collected by honeybees from several plant sources. This research aimed at showing its protective effect against UVA-induced apoptosis of human keratinocyte HaCaT cells. Using Hoechst staining, it was demonstrated that propolis (5 and 10 μg/mL) significantly inhibited the apoptosis of HaCaT cells induced by UVA-irradiation. Propolis also showed the protective effect against loss of mitochondrial membrane potential induced by UVA-irradiaiton in HaCaT cells. Propolis also inhibited the expression of activated caspase-3 induced by UVA-irradiation. To investigate the role of ROS in UVA-induced apoptosis and protection by propolis, the generation of ROS was determined in cells. The results showed that the generation of ROS was markedly reduced in cells pretreated with propolis. Consequently, propolis protected human keratinocyte HaCaT cells against UVA-induced apoptosis, which might be related to the reduction of ROS generation by UVA-irradiation.

Effects of Brazilian Propolis on Dental Plaque and Gingiva in Patients with Oral Cleft Malformation Treated with Multibracket and Removable Appliances: A Comparative Study

Orthodontic appliances modify the local environment of the oral cavity, increase the accumulation of dental plaque, and affect the condition of the gingiva. The aim of this study is assessment of Brazilian propolis toothpaste's effect on plaque index (PLI) and gingival index (GI) in patients with CL/CLP treated using orthodontic appliances in the 35-day study period. The study population included 96 patients of an Orthodontic Outpatient Clinic, ACSiMS in Bytom. All the patients participated in the active phase of orthodontic treatment using buccal multibracket appliances or removable appliances. During the first examination, each patient was randomly qualified to the propolis group or control group. A statistically significant decrease in GI and PLI in the entire propolis group (P < 0.01) was shown during repeated examination. Insignificant change in GI was in the entire control group during the repeated examination compared to the baseline. Similar result was obtained in patients treated with multibracket and removable appliances. The orthodontic appliance type did not affect the final dental plaque amount and gingival condition in patients using the propolis toothpaste. These results may be clinically useful to improve prevention and control oral infectious diseases during orthodontic treatment patients with oral cleft.

Chemical composition and antimicrobial activity of honeybee (Apis mellifera ligustica) propolis from subtropical eastern Australia

Propolis is a material manufactured by bees and contains beeswax, bee salivary secretions and plant resins. Propolis preparations have been used for millennia by humans in food, cosmetics and medicines due to its antibacterial effects. Within the hive, propolis plays an important role in bees' health, with much of its bioactivity largely dependent on the plant resins the bees select for its production. Few chemical studies are available on the chemistry of propolis produced by Australian honeybees (Apis mellifera, Apidae). This study aimed to determine the chemical composition as well as in vitro antimicrobial effects of propolis harvested from honeybees in subtropical eastern Australia. Honeybee propolis was produced using plastic frames and multiple beehives in two subtropical sites in eastern Australia. Methanolic extracts of propolis were analysed by liquid chromatography with ultraviolet detection and high-resolution mass spectrometry (ultra-high-pressure liquid chromatography (UHPLC)-UV-high-resolution tandem mass spectrometry (HR-MS/MS)) and by gas chromatography mass spectrometry (GC-MS). The resulting chemical data were dereplicated for compound characterisation. The two crude extracts in abs. ethanol were tested in vitro by the agar diffusion and broth dilution methods, using a phenol standard solution as the positive control and abs. ethanol as the negative control. Chemical constituents were identified to be pentacyclic triterpenoids and C-prenylated flavonoids, including Abyssinoflavanone VII, Propolin C and Nymphaeol C. The two propolis crude extracts showed bactericidal effects at the minimal inhibitory concentrations of 0.37-2.04 mg mL(-1) against Staphylococcus aureus ATCC 25923. However, the extracts were inactive against Klebsiella pneumoniae ATCC 13883 and Candida albicans ATCC 10231. The antistaphylococcal potential of propolis was discussed, also in relation to honeybees' health, as it warrants further investigations on the social and individual immunities of Australian honeybees.

Dietary amelioration of Helicobacter infection

We review herein the basis for using dietary components to treat and/or prevent Helicobacter pylori infection, with emphasis on (a) work reported in the last decade, (b) dietary components for which there is mechanism-based plausibility, and (c) components for which clinical results on H pylori amelioration are available. There is evidence that a diet-based treatment may reduce the levels and/or the virulence of H pylori colonization without completely eradicating the organism in treated individuals. This concept was endorsed a decade ago by the participants in a small international consensus conference held in Honolulu, Hawaii, USA, and interest in such a diet-based approach has increased dramatically since then. This approach is attractive in terms of cost, treatment, tolerability, and cultural acceptability. This review, therefore, highlights specific foods, food components, and food products, grouped as follows: bee products (eg, honey and propolis); probiotics; dairy products; vegetables; fruits; oils; essential oils; and herbs, spices, and other plants. A discussion of the small number of clinical studies that are available is supplemented by supportive in vitro and animal studies. This very large body of in vitro and preclinical evidence must now be followed up with rationally designed, unambiguous human trials.

Herbal mouthwash containing extracts of Baccharis dracunculifolia as agent for the control of biofilm: clinical evaluation in humans

Baccharis dracunculifolia DC (Asteraceae), popularly known as “alecrim-do-campo,” is largely distributed in South America, is shown to exhibit protective actions against gastric ulcers, has anti-inflammatory properties, and is hepatoprotective. Several essential oils obtained from Baccharis species possess biological activities, such as antimicrobial and antivirus activities. This randomized controlled trial evaluated the efficacy of B. dracunculifolia in the reduction of dental biofilm, comparing this natural product with other mouthwashes already known in the dental market. In measuring the time after use of mouthwash (t = 1), there was no difference between products (P = 0.602); that is, subjects in the study had a similar PI after the first use. After one week (t = 2), there was no difference between the four products evaluated (P = 0.674), so, all research individuals completed the study with a similar reduction in dental biofilm between themselves but it was different from initial state (Friedman test). It is possible to conclude that B. dracunculifolia had the same efficiency of the materials used to oral hygiene in reduction of dental plaque and, consequently, prevention of dental caries. Thus, we can consider B. dracunculifolia as a good candidate for new material to be implemented in dental care.

Hepatoprotective and Pancreatoprotective Properties of the Ethanolic Extract of Nigerian Propolis

Objective:

Increased oxidative stress is associated with the progression of diabetic mellitus. In the present study, we investigated the effects of the ethanolic extract of Nigerian propolis (N. propolis) on markers of oxidative stress, histology of the liver and pancreas and glycaemia in alloxan-induced diabetic rats.

Materials and Methods:

Alloxan-induced hyperglycemic Wistar rats were treated with either metformin (150 mg/kg/d) or N. propolis (200 mg/kg/d and 300 mg/kg/d) for 28 days. At the end of the treatment period, the rats were sacrificed; blood was collected for biochemical analysis while their pancreases and liver were excised and processed for histological studies.

Results:

Serum oxidative stress markers and blood glucose concentration were compared between the treated and control rats. In contrast to the non-treated diabetic rats, blood glucose concentration were not significantly different between treated rats and control (P < 0.05) at 28 days of treatment with N. propolis and metformin. Serum malondialdehyde levels was reduced while superoxide dismutase levels were elevated in the N. propolis group; these levels were converse in the diabetic group, these differences are statistically significant (P<0.05) when compared with the control. Histologically, there was improvement in the treated group compared to the untreated group.

Conclusion:

These findings suggest that the N. propolis confers protection against hyperglycemia-induced oxidative stress in both liver and pancreas of adult Wistar rats.

Characterisation of triterpenes and new phenolic lipids in Cameroonian propolis

Chemical investigation of a sample of propolis originating from North-Western Cameroon led to the isolation of thirteen alk(en)ylphenols (1-13) (inseparable mixture) along with α-amyrin (14), β-amyrin (15), lupeol (16), cycloartenol (17), mangiferonic acid (18), ambonic acid (19), mangiferolic acid (20), ambolic acid (21), isomangiferolic acid (22) and nine alk(en)ylresorcinols (23-31) (inseparable mixture). All compounds were identified following analysis of their spectroscopic data and comparison with previously published reports. Compounds (8), (12), (13) and (30) are new natural products. GC-MS analysis carried out on the alk(en)ylphenol and alk(en)ylresorcinol mixtures (dimethyl disulphide trimethylsilyl derivatives) revealed the presence of saturated and mono-unsaturated compounds with side chain lengths ranging from C11 to C19 and C15 to C19, respectively. The position of the double bond in mono-unsaturated derivatives was established from the characteristic fragments resulting from the cleavage of the bond between the two methylthio-substituted carbons. The most abundant compound in each mixture was 3-(12'Z-heptadecenyl)-phenol (10) and 5-(12'Z-heptadecenyl)-resorcinol (29). This study is the first to report the presence of triterpenes (except for lupeol) and phenolic lipids, including eighteen compounds previously unreported in bee glue, in an African sample.

Antidepressant- and anxiolytic-like activities of an oil extract of propolis in rats

PURPOSE

Propolis biological effects are mainly attributed to its polyphenolic constituents such as flavonoids and phenolic acids that were recently described in the chemical composition of an extract of propolis obtained with edible vegetal oil (OEP) by our group. The aim of this study was to evaluate the effect of OEP on the behavior of rats.

MATERIALS AND METHODS

An in vivo open field (OF), elevated Plus-maze (EPM), and forced swimming (FS) tests were performed to evaluate locomotor activity, anxiolytic- and antidepressant effects of the extract. Besides, oxidative stress levels were measured in rat blood samples after the behavioral assays by evaluation of the Trolox equivalent antioxidant capacity (TEAC) and nitric oxide levels.

RESULTS

OEP increased locomotion in the OF test (50mg/kg) and central locomotion and open arm entries in the OF and EPM tests (10-50mg/kg) and decreased the immobility time in the FS test (10-50mg/kg). Moreover, OEP reduced nitric oxide levels in response to swim stress induced in rats.

CONCLUSION

OEP exerted stimulant, anxiolytic and antidepressant effects on the Central Nervous System and antioxidant activity in rats, highlighting propolis as a potential therapeutic compound for behavior impairment of anxiety and depression.

Medicinal plant activity on Helicobacter pylori related diseases

More than 50% of the world population is infected with Helicobacter pylori (H. pylori). The bacterium highly links to peptic ulcer diseases and duodenal ulcer, which was classified as a group I carcinogen in 1994 by the WHO. The pathogenesis of H. pylori is contributed by its virulence factors including urease, flagella, vacuolating cytotoxin A (VacA), cytotoxin-associated gene antigen (Cag A), and others. Of those virulence factors, VacA and CagA play the key roles. Infection with H. pylori vacA-positive strains can lead to vacuolation and apoptosis, whereas infection with cagA-positive strains might result in severe gastric inflammation and gastric cancer. Numerous medicinal plants have been reported for their anti-H. pylori activity, and the relevant active compounds including polyphenols, flavonoids, quinones, coumarins, terpenoids, and alkaloids have been studied. The anti-H. pylori action mechanisms, including inhibition of enzymatic (urease, DNA gyrase, dihydrofolate reductase, N-acetyltransferase, and myeloperoxidase) and adhesive activities, high redox potential, and hydrophilic/hydrophobic natures of compounds, have also been discussed in detail. H. pylori-induced gastric inflammation may progress to superficial gastritis, atrophic gastritis, and finally gastric cancer. Many natural products have anti-H. pylori-induced inflammation activity and the relevant mechanisms include suppression of nuclear factor-κB and mitogen-activated protein kinase pathway activation and inhibition of oxidative stress. Anti-H. pylori induced gastric inflammatory effects of plant products, including quercetin, apigenin, carotenoids-rich algae, tea product, garlic extract, apple peel polyphenol, and finger-root extract, have been documented. In conclusion, many medicinal plant products possess anti-H. pylori activity as well as an anti-H. pylori-induced gastric inflammatory effect. Those plant products have showed great potential as pharmaceutical candidates for H. pylori eradication and H. pylori induced related gastric disease prevention.

Natural products and food components with anti-Helicobacter pylori activities

The bacterial pathogen Helicobacter pylori (H. pylori) colonizes in over half of the world’s population. H. pylori that establishes life-long infection in the stomach is definitely associated with gastro-duodenal diseases and a wide variety of non-gastrointestinal tract conditions such as immune thrombocytopenia. Triple therapy which consists of a proton pump inhibitor and combinations of two antibiotics (amoxicillin, clarithromycin or amoxicillin, metronidazol) is commonly used for H. pylori eradication. Recently, the occurrence of drug-resistant H. pylori and the adverse effect of antibiotics have severely weakened eradication therapy. Generally antibiotics induce the disturbance of human gastrointestinal microflora. Furthermore, there are inappropriate cases of triple therapy such as allergy to antibiotics, severe complications (liver and/or kidney dysfunction), the aged and people who reject the triple therapy. These prompt us to seek alterative agents instead of antibiotics and to develop more effective and safe therapy with these agents. The combination of these agents actually may result in lower a dose of antibiotics. There are many reports world-wide that non-antibiotic substances from natural products potentially have an anti-H. pylori agent. We briefly review the constituents derived from nature that fight against H. pylori in the literature with our studies.

Use of propolis in the sanitization of lettuce

The present study aimed to determine the effectiveness of propolis in reducing the microbial load in ready-to-eat (RTE) and fresh whole head (FWH) lettuces (Lactuca sativa L.) type Batavia. Two sanitizing solutions were employed: sodium hypochlorite (SH) and propolis (PS), during 15 and 30 min. Tap water (TW) was used as a control. Regarding the mean reduction on aerobic mesophiles, psychrotrophic and fecal coliforms, the SH and PS treatments showed the same pattern of variation. In all cases, PS was slightly more effective in the microbiological reduction in comparison with commercial SH. Reductions between two and three log cycles were obtained with PS on aerobic mesophiles and psychrotrophic counts. The information obtained in the present study can be used to evaluate the potential use of propolis as product for sanitizing other vegetables and for developing other food preservation technologies, with impact on human health.

Protective effects of Baccharis dracunculifolia leaves extract against carbon tetrachloride- and acetaminophen-induced hepatotoxicity in experimental animals

In this work we investigated the in vivo protective effects of Baccharis dracunculifolia leaves extract (BdE) against carbon tetrachloride (CCl₄)- and acetaminophen (APAP)-induced hepatotoxicity. Total phenolic content, total flavonoid content, antioxidant DPPH radical scavenging activity, and HPLC analysis were performed. Our results showed that pretreatment with BdE significantly reduced the damage caused by CCl₄ and APAP on the serum markers of hepatic injury, AST, ALT, and ALP. Results were confirmed by histopathological analysis. Phytochemical analysis, performed by HPLC, showed that BdE was rich in p-coumaric acid derivatives, caffeoylquinic acids and flavonoids. BdE also showed DPPH antioxidant activity (EC₅₀ of 15.75 ± 0.43 μg/mL), and high total phenolic (142.90 ± 0.77 mg GAE/g) and flavonoid (51.47 ± 0.60 mg RE/g) contents. This study indicated that B. dracunculifolia leaves extract has relevant in vivo hepatoprotective properties.

Overview of the phytomedicine approaches against Helicobacter pylori

Helicobacter pylori (H. pylori) successfully colonizes the human stomach of the majority of the human population. This infection always causes chronic gastritis, but may evolve to serious outcomes, such as peptic ulcer, gastric carcinoma or mucosa-associated lymphoid tissue lymphoma. H. pylori first line therapy recommended by the Maastricht-4 Consensus Report comprises the use of two antibiotics and a proton-pomp inhibitor, but in some regions failure associated with this treatment is already undesirable high. Indeed, treatment failure is one of the major problems associated with H. pylori infection and is mainly associated with bacterial antibiotic resistance. In order to counteract this situation, some effort has been allocated during the last years in the investigation of therapeutic alternatives beyond antibiotics. These include vaccines, probiotics, photodynamic inactivation and phage therapy, which are briefly revisited in this review. A particular focus on phytomedicine, also described as herbal therapy and botanical therapy, which consists in the use of plant extracts for medicinal purposes, is specifically addressed, namely considering its history, category of performed studies, tested compounds, active principle and mode of action. The herbs already experienced are highly diverse and usually selected from products with a long history of employment against diseases associated with H. pylori infection from each country own folk medicine. The studies demonstrated that many phytomedicine products have an anti-H. pylori activity and gastroprotective action. Although the mechanism of action is far from being completely understood, current knowledge correlates the beneficial action of herbs with inhibition of essential H. pylori enzymes, modulation of the host immune system and with attenuation of inflammation.

Current knowledge on alleviating Helicobacter pylori infections through the use of some commonly known natural products: bench to bedside

Helicobacter pylori, a spiral-shaped Gram-negative bacterium, has been classified as a class I carcinogen by the World Health Organization and recognized as the causative agent for peptic ulcers, duodenal ulcer, gastritis, mucosa-associated lymphoid tissue lymphomas, and gastric cancer. Owing to their alarming rate of drug resistance, eradication of H. pylori remains a global challenge. Triple therapy consisting of a proton pump inhibitor, clarithromycin, and either amoxicillin or metronidazole, is generally the recommended standard for the treatment of H. pylori infection. Complementary and alternative medicines have a long history in the treatment of gastrointestinal ailments and various compounds has been tested for anti-H. pylori activity both in vitro and in vivo; however, their successful use in human clinical trials is sporadic. Hence, the aim of this review is to analyze the role of some well-known natural products that have been tested in clinical trials in preventing, altering, or treating H. pylori infections. Whereas some in vitro and in vivo studies in the literature have demonstrated the successful use of a few potential natural products for the treatment of H. pylori-related infections, others indicate a need to consider natural products, with or without triple therapy, as a useful alternative in treating H. pylori-related infections. Thus, the reported mechanisms include killing of H. pylori urease inhibition, induction of bacterial cell damage, and immunomodulatory effect on the host immune system. Furthermore, both in vitro and in vivo studies have demonstrated the successful use of some potential natural products for the treatment of H. pylori-related infections. Nevertheless, the routine prescription of potential complementary and alternative medicines continues to be restrained, and evidence on the safety and efficacy of the active compounds remains a subject of ongoing debate.

Korean Propolis Suppresses Angiogenesis through Inhibition of Tube Formation and Endothelial Cell Proliferation

Propolis, a sticky material that honeybees collect from living plants, has been used for its pharmaceutical properties since ancient times. In this study, we examined the effects of ethanol extracts of Korean propolis (EEKP) from various geographic regions on the inhibition of angiogenesis, both in vitro and in vivo. The effects of EEKP were tested on in vitro models of angiogenesis, that is, tube formation and proliferation of human umbilical vein endothelial cells (HUVECs). All EEKP samples exhibited significant inhibitory effects on tube formation of HUVECs in a concentration-dependent manner (6.25-25 μg/mL). In addition, two EEKP samples, prepared from Uijeongbu and Pyoseon propolis, significantly suppressed the proliferation of HUVECs in a concentration-dependent manner (3.13-25 μg/mL). Furthermore, in an in vivo angiogenesis assay using the chick embryo chorioallantoic membrane (CAM) system, we found that the two EEKP samples significantly reduced the number of newly formed vessels. These results indicate that Korean propolis may have potential applications in the prevention and treatment of angiogenesis-related diseases such as cancer.

Exploring alternative treatments for Helicobacter pylori infection

Helicobacter pylori (H. pylori) is a successful pathogen that can persist in the stomach of an infected person for their entire life. It provokes chronic gastric inflammation that leads to the development of serious gastric diseases such as peptic ulcers, gastric cancer and Mucosa associated lymphoid tissue lymphoma. It is known that these ailments can be avoided if the infection by the bacteria can be prevented or eradicated. Currently, numerous antibiotic-based therapies are available. However, these therapies have several inherent problems, including the appearance of resistance to the antibiotics used and associated adverse effects, the risk of re-infection and the high cost of antibiotic therapy. The delay in developing a vaccine to prevent or eradicate the infection has furthered research into new therapeutic approaches. This review summarises the most relevant recent studies on vaccine development and new treatments using natural resources such as plants, probiotics and nutraceuticals. In addition, novel alternatives based on microorganisms, peptides, polysaccharides, and intragastric violet light irradiation are presented. Alternative therapies have not been effective in eradicating the bacteria but have been shown to maintain low bacterial levels. Nevertheless, some of them are useful in preventing the adverse effects of antibiotics, modulating the immune response, gastroprotection, and the general promotion of health. Therefore, those agents can be used as adjuvants of allopathic anti-H. pylori eradication therapy.