Chemical composition and pharmacological properties of Macaranga ‐type Pacific propolis: A review

A novel black poplar propolis extract with promising health-promoting properties: focus on its chemical composition, antioxidant, anti-inflammatory, and anti-genotoxic activities

Propolis is a resinous mixture produced by honeybees which has been used since ancient times for its useful properties. However, its chemical composition and bioactivity may vary, depending on the geographical area of origin and the type of tree bees use for collecting pollen. In this context, this research aimed to investigate the total phenolic content (using the Folin-Ciocalteu assay) and the total antioxidant capacity (using the FRAP, DPPH, and ABTS assays) of three black poplar (Populus nigra L.) propolis (BPP) solutions (S1, S2, and S3), as well as the chemical composition (HPLC-ESI-MSn) and biological activities (effect on cell viability, genotoxic/antigenotoxic properties, and anti-inflammatory activity, and effect on ROS production) of the one which showed the highest antioxidant activity (S1). The hydroalcoholic BPP solution S1 was a prototype of an innovative, research-type product by an Italian nutraceutical manufacturer. In contrast, hydroalcoholic BPP solutions S2 and S3 were conventional products purchased from local pharmacy stores. For the three extracts, 50 phenolic compounds, encompassing phenolic acids and flavonoids, were identified. In summary, the results showed an interesting chemical profile and the remarkable antioxidant, antigenotoxic, anti-inflammatory and ROS-modulating activities of the innovative BPP extract S1, paving the way for future research. In vivo investigations will be a possible line to take, which may help corroborate the hypothesis of the potential health benefits of this product, and even stimulate further ameliorations of the new prototype.

Comparison of the Chemical Composition and Antioxidant Properties of Propolis from Urban Apiaries

Bee products from urban apiaries are increasingly used. They are mainly used to promote local apiaries and cities in which they are located. The aim of the study was to compare the chemical composition and antioxidant activity of propolis from 6 Polish apiaries located in cities (Legionowo, Torun, Cracow, Warsaw, Katowice, Lodz). The chemical composition was analyzed using liquid chromatography (HPLC-DAD) and the analysis of antioxidant activity by scavenging free radicals (ABTS and DPPH) and FRAP. The obtained results showed the presence of 24 phenolic compounds in propolis extracts. The tested samples showed differentiation in terms of the content of individual chemical components, however, cinnamic acid and its derivatives were dominant. High antioxidant activity of the tested extracts was demonstrated (ABTS was in the range of 16.80-51.53 mg Te/mL, DPPH was in the range of 7.54-22.13 mg Te/mL, while FRAP reduction was in the range of 10.93-29.55 mg Te/mL). The obtained results compared with literature data on propolis from agricultural areas allow to conclude that propolis samples from both Poland types of areas are similar and can be classified as poplar propolis.

Lactic Acid Bacteria (LAB) and Neuroprotection, What Is New? An Up-To-Date Systematic Review

BACKGROUND

In recent years, the potential role of probiotics has become prominent in the discoveries of neurotherapy against neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases. Lactic acid bacteria (LAB) exhibit neuroprotective properties and exert their effects via various mechanisms of actions. This review aimed to evaluate the effects of LAB on neuroprotection reported in the literature.

METHODS

A database search on Google Scholar, PubMed, and Science Direct revealed a total of 467 references, of which 25 were included in this review based on inclusion criteria which comprises 7 in vitro, 16 in vivo, and 2 clinical studies.

RESULTS

From the studies, LAB treatment alone or in probiotics formulations demonstrated significant neuroprotective activities. In animals and humans, LAB probiotics supplementation has improved memory and cognitive performance mainly via antioxidant and anti-inflammatory pathways.

CONCLUSIONS

Despite promising findings, due to limited studies available in the literature, further studies still need to be explored regarding synergistic effects, efficacy, and optimum dosage of LAB oral bacteriotherapy as treatment or prevention against neurodegenerative diseases.

Diallyl disulfide downregulating RhoGDI2 induces differentiation and inhibit invasion via the Rac1/Pak1/LIMK1 pathway in human leukemia HL-60 cells

Leukemia is a type of disease in which hematopoietic stem cells proliferate clonally at the genetic level. We discovered previously by high-resolution mass spectrometry that diallyl disulfide (DADS), which is one of the effective ingredients of garlic, reduces the performance of RhoGDI2 from APL HL-60 cells. Although RhoGDI2 is oversubscribed in several cancer categories, the effect of RhoGDI2 in HL-60 cells has remained unexplained. We aimed to investigate the influence of RhoGDI2 on DADS-induced differentiation of HL-60 cells to elucidate the association among the effect of inhibition or over-expression of RhoGDI2 with HL-60 cell polarization, migration and invasion, which is important for establishing a novel generation of inducers to elicit leukemia cell polarization. Co-transfection with RhoGDI2-targeted miRNAs apparently decreases the malignant biological behavior of cells and upregulates cytopenias in DADS-treated HL-60 cell lines, which increases CD11b and decreases CD33 and mRNA levels of Rac1, PAK1 and LIMK1. Meanwhile, we generated HL-60 cell lines with high-expressing RhoGDI2. The proliferation, migration and invasion capacity of such cells were significantly increased by the treated with DADS, while the reduction capacity of the cells was decreased. There was a reduction in CD11b and an increase in CD33 production, as well as an increase in the mRNA levels of Rac1, PAK1 and LIMK1. It also confirmed that inhibition of RhoGDI2 attenuates the EMT cascade via the Rac1/Pak1/LIMK1 pathway, thereby inhibiting the malignant biological behavior of HL-60 cells. Thus, we considered that inhibition of RhoGDI2 expression might be a new therapeutic direction for the treatment of human promyelocytic leukemia. The anti-cancer property of DADS against HL-60 leukemia cells might be regulated by RhoGDI2 through the Rac1-Pak1-LIMK1 pathway, which provides new evidence for DADS as a clinical anti-cancer medicine.

Effect of Hydrogen-Enriched Solvents on the Extraction of Phytochemicals in Propolis

Propolis, one of the most important bee products, cannot be used in its raw form. The efficiency of the bioactive components of propolis increases with the extraction process. The choice of solvent to be used in the extraction of propolis is effective in determining the properties of the extract. Ethanol is the most widely used solvent, which significantly increases the efficiency of its bioactive components in the extraction of propolis. Effective nonalcohol-based extraction techniques have become important since alcohol-based extracts cause some discomfort and cannot be used in people with alcohol intolerance. The use of water in propolis extraction is less preferred than ethanol because it does not thoroughly dissolve the bioactive components. In this study, the effect of incorporating hydrogen into solvents (water, ethanol, and methanol) on the extraction of total phenolic content, total flavonoid content, antioxidant activities, and phenolic compound profile of the propolis sample was evaluated. Incorporation of H₂ into water, ethanol, and methanol led to an increase in total phenolic content by 19.08, 5.43, and 12.71% and in the total flavonoid content by 28.97, 17.13, and 2.06%, respectively. Besides, the highest increases in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) scavenging activities were observed in hydrogen-rich water (4.4%) and hydrogen-rich ethanol (32.4%) compared to their counterparts, respectively. On the other hand, incorporation of H₂ into different solvents led to significant increases in different phenolics, and it was observed that the level of change was dependent on the type of the phenolic compound and the solvent used. This study is important in terms of using hydrogen-enriched solvents to extract phenolics from propolis for the first time. Using hydrogen-rich solvents, specifically hydrogen-rich water, was observed to be an effective method for the improvement of phytochemical extraction efficiency in propolis.

Allergic Inflammation: Effect of Propolis and Its Flavonoids

The incidence of allergic diseases and their complications are increasing worldwide. Today, people increasingly use natural products, which has been termed a "return to nature". Natural products with healing properties, especially those obtained from plants and bees, have been used in the prevention and treatment of numerous chronic diseases, including allergy and/or inflammation. Propolis is a multi-component resin rich in flavonoids, collected and transformed by honeybees from buds and plant wounds for the construction and adaptation of their nests. This article describes the current views regarding the possible mechanisms and multiple benefits of flavonoids in combating allergy and allergy-related complications. These benefits arise from flavonoid anti-allergic, anti-inflammatory, antioxidative, and wound healing activities and their effects on microbe-immune system interactions in developing host responses to different allergens. Finally, this article presents various aspects of allergy pathobiology and possible molecular approaches in their treatment. Possible mechanisms regarding the antiallergic action of propolis on the microbiota of the digestive and respiratory tracts and skin diseases as a method to selectively remove allergenic molecules by the process of bacterial biotransformation are also reported.

Antibacterial and Antioxidant Activity of the Fruit of Macaranga tanarius, the Plant Origin of Taiwanese Green Propolis

Taiwanese green propolis (TGP) is widely used in traditional medicine and exerts a broad spectrum of biological activities, including those anti-inflammatory and anti-cancer in nature, resulting from an abundant level of functional propolins (prenylated flavanone) in the TGP. However, the plant origin of TGP has not been clarified. In this study, we collected the surface material of Macaranga tanarius fruit and comparatively analyzed the chemical composition, antibacterial activity, and antioxidant activity with TGP. The results revealed that there was no difference between the chemical composition of the glandular trichome extract of M. tanarius and those in propolis. Moreover, M. tanarius fruit extract was enriched in propolins (C, D, F, and G) and effectively inhibited the growth of Gram-positive strains. Propolins, TGP, and M. tanarius fruit extract showed powerful free radical-scavenging and ferrous-reducing activity. Collectively, we have confirmed the plant source of TGP is M. tanarius, and this plant has the enormous potential to be developed as a pharmaceutical plant due to the potent biological activities and the high amount of functional propolins.

Comparison of the Antioxidant Activity of Propolis Samples from Different Geographical Regions

Propolis composition depends on several factors. The classification of propolis is based on its geographical location, color and agricultural characteristics. It is also classified according to the flora where the bees collect the resins, which represent the raw material for propolis production. Propolis possesses high antioxidant activity determined by its phenolic compounds. Due to diverse composition and possible impact on human health, eight samples of propolis were evaluated for their phenolic composition and antioxidant activity. Samples of Polish, Romanian, Turkish and Uruguayan origin propolis were used for phenolic spectrum determination using high performance liquid chromatography and photodiode array detection and in vitro DPPH and ABTS methods were used to determine the antioxidant activity of the extracts. PCA and HCA models were applied to evaluate the correlation between isolated polyphenols and antioxidant activity. The results confirmed variability in propolis composition depending on the geographical region of collection and the plant sources, and correlation between chemical composition and antioxidant activity. Results of PCA and HCA analyses confirm that Polish propolis is similar to that from different provinces of Romania, while Turkish and Uruguay are completely different. Polish and Romanian propolis belong to the poplar type. The assessed phenolic compounds of propolis samples used in the study are responsible for its antioxidant effect. The observed antioxidant activity of the analyzed samples may suggest directing subsequent research on prophylactic and therapeutic properties concerning cardiovascular, metabolic, neurodegenerative, and cancerous diseases, which are worth continuing.

In Vitro and In Silico Anti-Acetylcholinesterase Activity from Macaranga tanarius and Syzygium jambos

Macaranga tanarius (MT) and Syzygium jambos (SJ) are pharmacologically reported to have anti-oxidant, anti-inflammatory, and anti-diabetic effects, and can be neuroprotective agents. Our previous work revealed that MT and SJ exhibited 76.32% and 93.81% inhibition against acetylcholinesterase (AChE) at 50 μg/mL final concentration in their ethyl acetate and hexane fractions, respectively. This study was aimed to investigate the bioactive constituents of MT and SJ and their molecular mechanism toward AChE inhibition. Bioassay-guided isolation afforded prenylflavonoids 1–3 from MT and anacardic acid derivatives 4 and 5 from SJ that were confirmed by NMR and MS data. Compound 5 exerted the strongest anti-AChE potential (IC₅₀: 0.54 μM), followed by 1, 4, 3, and 2 (IC₅₀: 1.0, 2.4, 6.8, and 33 μM, respectively). In silico molecular docking revealed 5 formed stronger molecular interactions including three H-bonds than its derivative 4 based on the saturation of their alkyl chains. The addition of a five carbon-prenyl chain in 1 increased the number of binding interactions, justifying its greater activity than derivatives 2 and 3. This research reflects the first report of AChE inhibitors from these species, thereby adding pharmacological values to MT and SJ as potential remedies in neuroprotection.

Propolin G-Suppressed Epithelial-to-Mesenchymal Transition in Triple-Negative Breast Cancer Cells via Glycogen Synthase Kinase 3β-Mediated Snail and HDAC6-Regulated Vimentin Degradation

Triple-negative breast cancer (TNBC) is a highly aggressive breast cancer with a poor prognosis. The incidence and mortality rate of TNBC are frequently found in younger women. Due to the absence of a good therapeutic strategy, effective remedies for inhibiting TNBC have been developed for improving the cure rate. Epithelial-to-mesenchymal transition (EMT) is a critical mechanism to regulate cancer cell motility and invasion. Furthermore, ectopic expression of EMT molecules correlates with the metastasis and poor prognosis of TNBC. Targeting EMT might be a strategy for the therapy and prevention of TNBC. Propolin G, an active c-prenylflavanone in Taiwanese propolis, has been shown to possess anti-cancer activity in many cancers. However, the anti-metastasis activity of propolin G on TNBC is still unclear. The present study showed that the migration and invasion activities of TNBC cells was suppressed by propolin G. Down-regulated expression of Snail and vimentin and up-regulated expression of E-cadherin were dose- and time-dependently observed in propolin G-treated MDA-MB-231 cells. Propolin G inhibited Snail and vimentin expressions via the signaling pathways associated with post-translational modification. The activation of glycogen synthase kinase 3β (GSK-3β) by propolin G resulted in increasing GSK-3β interaction with Snail. Consequently, the nuclear localization and stability of Snail was disrupted resulting in promoting the degradation. Propolin G-inhibited Snail expression and the activities of migration and invasion were reversed by GSK-3β inhibitor pretreatment. Meanwhile, the outcomes also revealed that histone deacetylase 6 (HDAC6) activity was dose-dependently suppressed by propolin G. Correspondently, the amounts of acetyl-α-tubulin, a down-stream substrate of HDAC6, were increased. Dissociation of HDAC6/Hsp90 with vimentin leading to increased vimentin acetylation and degradation was perceived in the cells with the addition of propolin G. Moreover, up-regulated expression of acetyl-α-tubulin by propolin G was attenuated by HDAC6 overexpression. On the contrary, down-regulated expression of vimentin, cell migration and invasion by propolin G were overturned by HDAC6 overexpression. Conclusively, restraint cell migration and invasion of TNBC by propolin G were activated by the expression of GSK-3β-suppressed Snail and the interruption of HDAC6-mediated vimentin protein stability. Aiming at EMT, propolin G might be a potential candidate for TNBC therapy.

Propolis: chemical diversity and challenges in quality control

Propolis is a resinous natural product produced by honeybees using beeswax and plant exudates. The chemical composition of propolis is highly complex, and varies with region and season. This inherent chemical variability presents several challenges to its standardisation and quality control. The present review was aimed at highlighting marker compounds for different types of propolis, produced by the species Apis mellifera, from different geographical origins and that display different biological activities, and to discuss strategies for quality control. Over 800 compounds have been reported in the different propolises such as temperate, tropical, birch, Mediterranean, and Pacific propolis; these mainly include alcohols, acids and their esters, benzofuranes, benzopyranes, chalcones, flavonoids and their esters, glycosides (flavonoid and diterpene), glycerol and its esters, lignans, phenylpropanoids, steroids, terpenes and terpenoids. Among these, flavonoids (> 140), terpenes and terpenoids (> 160) were major components. A broad range of biological activities, such as anti-oxidant, antimicrobial, anti-inflammatory, immunomodulatory, and anticancer activities, have been ascribed to propolis constituents, as well as the potential of these compounds to be biomarkers. Several analytical techniques, including non-separation and separation methods have been described in the literature for the quality control assessment of propolis. Mass spectrometry coupled with separation methods, followed by chemometric analysis of the data, was found to be a valuable tool for the profiling and classification of propolis samples, including (bio)marker identification. Due to the rampant chemotypic variability, a multiple-marker assessment strategy considering geographical and biological activity marker(s) with chemometric analysis may be a promising approach for propolis quality assessment.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11101-022-09816-1.

Propolis: Chemical Constituents, Plant Origin, and Possible Role in the Prevention and Treatment of Obesity and Diabetes

Honeybee products are not only beneficial to human health but also important to the food industry. One such product is propolis, a resinous substance that honeybees collect from certain trees and plants and store inside their hives. Although various health benefits of propolis have been reported, the chemical composition of propolis varies greatly depending on the growing region and plant origin. These differences have led to many misconceptions and conflicting research results. In this paper, we review research findings on how the growing region and plant origin of propolis affects its composition. We also discuss trends in research on the antiobesity and antidiabetes effects of propolis as well as recent findings that a major component of Brazilian green propolis modulates adipocyte function. Finally, we discuss challenges to be tackled in future research on the health benefits of propolis and share our perspective on the future of this field.

The antiviral and immunomodulatory activities of propolis: An update and future perspectives for respiratory diseases

Propolis is a complex natural product that possesses antioxidant, anti‐inflammatory, immunomodulatory, antibacterial, and antiviral properties mainly attributed to the high content in flavonoids, phenolic acids, and their derivatives. The chemical composition of propolis is multifarious, as it depends on the botanical sources from which honeybees collect resins and exudates. Nevertheless, despite this variability propolis may have a general pharmacological value, and this review systematically compiles, for the first time, the existing preclinical and clinical evidence of propolis activities as an antiviral and immunomodulatory agent, focusing on the possible application in respiratory diseases. In vitro and in vivo assays have demonstrated propolis broad‐spectrum effects on viral infectivity and replication, as well as the modulatory actions on cytokine production and immune cell activation as part of both innate and adaptive immune responses. Clinical trials confirmed propolis undeniable potential as an effective therapeutic agent; however, the lack of rigorous randomized clinical trials in the context of respiratory diseases is tangible. Since propolis is available as a dietary supplement, possible use for the prevention of respiratory diseases and their deleterious inflammatory drawbacks on the respiratory tract in humans is considered and discussed. This review opens up new perspectives on the clinical investigation of neglected propolis biological properties which, now more than ever, are particularly relevant with respect to the recent outbreaks of pandemic respiratory infections.

p21-Activated kinase 1 (PAK1) in aging and longevity: An overview

The p21-activated kinases (PAKs) belong to serine/threonine kinases family, regulated by ∼21 kDa small signaling G proteins RAC1 and CDC42. The mammalian PAK family comprises six members (PAK1-6) that are classified into two groups (I and II) based on their domain architecture and regulatory mechanisms. PAKs are implicated in a wide range of cellular functions. PAK1 has recently attracted increasing attention owing to its involvement in oncogenesis, tumor progression, and metastasis as well as several life-limiting diseases and pathological conditions. In Caenorhabditis elegans, PAK1 functions limit the lifespan under basal conditions by inhibiting forkhead transcription factor DAF-16. Interestingly, PAK depletion extended longevity and attenuated the onset of age-related phenotypes in a premature-aging mouse model and delayed senescence in mammalian fibroblasts. These observations implicate PAKs as not only oncogenic but also aging kinases. Therefore, PAK-targeting genetic and/or pharmacological interventions, particularly PAK1-targeting, could be a viable strategy for developing cancer therapies with relatively no side effects and promoting healthy longevity. This review describes PAK family proteins, their biological functions, and their role in regulating aging and longevity using C. elegans. Moreover, we discuss the effect of small-molecule PAK1 inhibitors on the lifespan and healthspan of C. elegans.

Experimental Evidence for Therapeutic Potentials of Propolis

Propolis is produced by honeybees from materials collected from plants they visit. It is a resinous material having mixtures of wax and bee enzymes. Propolis is also known as bee glue and used by bees as a building material in their hives, for blocking holes and cracks, repairing the combs and strengthening their thin borders. It has been extensively used since ancient times for different purposes in traditional human healthcare practices. The quality and composition of propolis depend on its geographic location, climatic zone and local flora. The New Zealand and Brazilian green propolis are the two main kinds that have been extensively studied in recent years. Their bioactive components have been found to possess a variety of therapeutic potentials. It was found that Brazilian green propolis improves the cognitive functions of mild cognitive impairments in patients living at high altitude and protects them from neurodegenerative damage through its antioxidant properties. It possesses artepillin C (ARC) as the key component, also known to possess anticancer potential. The New Zealand propolis contains caffeic acid phenethyl ester (CAPE) as the main bioactive with multiple therapeutic potentials. Our lab performed in vitro and in vivo assays on the extracts prepared from New Zealand and Brazilian propolis and their active ingredients. We provided experimental evidence that these extracts possess anticancer, antistress and hypoxia-modulating activities. Furthermore, their conjugation with γCD proved to be more effective. In the present review, we portray the experimental evidence showing that propolis has the potential to be a candidate drug for different ailments and improve the quality of life.

Potential Role of Propolis in the Prevention and Treatment of Metabolic Diseases

Propolis is a resinous mixture with a complex chemical composition, produced by honeybees and stingless bees from a variety of vegetal sources. In the last decades, propolis was extensively researched, multiple studies confirming its anti-inflammatory, antioxidant, antimicrobial, and wound-healing properties. More recently, due to an exponential increase in the number of patients with metabolic diseases, there is also a growing interest in the study of antidiabetic, antihyperlipidemic, and anti-obesity effects of propolis. The aim of this review was to evaluate the potential role of propolis in the prevention and treatment of metabolic diseases like diabetes mellitus, dyslipidemia, and obesity. The preclinical in vivo and in vitro pharmacological models investigating antidiabetic, antihyperlipidemic, and anti-obesity effects of propolis were reviewed with a focus on the putative mechanisms of actions of several chemical constituents. Additionally, the available clinical studies and an evaluation of the safety profile of propolis were also presented.

Biomedical Properties of Propolis on Diverse Chronic Diseases and Its Potential Applications and Health Benefits

The use of alternative medicine products has increased tremendously in recent decades and it is estimated that approximately 80% of patients globally depend on them for some part of their primary health care. Propolis is a beekeeping product widely used in alternative medicine. It is a natural resinous product that bees collect from various plants and mix with beeswax and salivary enzymes and comprises a complex mixture of compounds. Various biomedical properties of propolis have been studied and reported in infectious and non-infectious diseases. However, the pharmacological activity and chemical composition of propolis is highly variable depending on its geographical origin, so it is important to describe and study the biomedical properties of propolis from different geographic regions. A number of chronic diseases, such as diabetes, obesity, and cancer, are the leading causes of global mortality, generating significant economic losses in many countries. In this review, we focus on compiling relevant information about propolis research related to diabetes, obesity, and cancer. The study of propolis could generate both new and accessible alternatives for the treatment of various diseases and will help to effectively evaluate the safety of its use.

Can Blood-Circulating Factors Unveil and Delay Your Biological Aging?

According to the World Health Organization, the population of over 60 will double in the next 30 years in the developed countries, which will enforce a further raise of the retirement age and increase the burden on the healthcare system. Therefore, there is an acute issue of maintaining health and prolonging active working longevity, as well as implementation of early monitoring and prevention of premature aging and age-related disorders to avoid early disability. Traditional indicators of biological age are not always informative and often require extensive and expensive analysis. The study of blood factors is a simple and easily accessible way to assess individual health and supplement the traditional indicators of a person's biological age with new objective criteria. With age, the processes of growth and development, tissue regeneration and repair decline; they are gradually replaced by enhanced catabolism, inflammatory cell activity, and insulin resistance. The number of senescent cells supporting the inflammatory loop rises; cellular clearance by autophagy and mitophagy slows down, resulting in mitochondrial and cellular damage and dysfunction. Monitoring of circulated blood factors not only reflects these processes, but also allows suggesting medical intervention to prevent or decelerate the development of age-related diseases. We review the age-related blood factors discussed in recent publications, as well as approaches to slowing aging for healthy and active longevity.