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

Metabolic, toxicological, chemical, and commercial perspectives on esterification of dietary polyphenols: a review

Molecular modifications have been practiced for more than a century and nowadays they are widely applied in food, pharmaceutical, or other industries to manipulate the physicochemical, bioactivity, metabolic/catabolic, and pharmacokinetic properties. Among various structural modifications, the esterification/O-acylation has been well-established in altering lipophilicity and bioactivity of parent bioactive compounds, especially natural polyphenolics, while maintaining their high biocompatibility. Meanwhile, various classic chemical and enzymatic protocols and other recently emerged cell factory technology are being employed as viable esterification strategies. In this contribution, the main motivations of phenolic esterification, including the tendency to replace synthetic alkyl phenolics with safer alternatives in the food industry to improve the bioavailability of phenolics as dietary supplements/pharmaceuticals, are discussed. In addition, the toxicity, metabolism, and commercial application of synthetic and natural phenolics are briefly introduced. Under these contexts, the mechanisms and reaction features of several most prevalent chemical and enzymatic esterification pathways are demonstrated. In addition, insights into the studies of esterification modification of natural phenolic compounds and specific pros/cons of various reaction systems with regard to their practical application are provided.

Is Propolis a Potential Anti-Obesogenic Agent for Obesity?

PURPOSE OF REVIEW

Propolis is a bee product that has been used for thousands of years. The chemical composition and biological activity of propolis, which has been investigated in the twentieth century, may vary according to location. Propolis polyphenols can induce thermogenesis in brown and beige fat tissue via the uncoupled protein-1 and creatinine kinase metabolic pathways. This review provides a comprehensive investigation of the structural and biological properties of propolis and provides insights into their promising potential strategies in body weight management.

RECENT FINDINGS

By raising overall energy expenditure, it might lead to body weight management. Furthermore, the phenolic components artepillin C, quercetin, catechin, and chlorogenic acid found in its composition may have anti-obesogenic effect by stimulating the sympathetic nervous system, enhancing browning in white adipose tissue, and triggering AMP-activated protein kinase activation and mitochondrial biogenesis. Propolis, a natural product, is effective in preventing obesity which is a contemporary pandemic.

Effects of caffeic acid phenethyl ester against multi-species cariogenic biofilms

Dental caries is a biofilm-related disease, widely perceived to be caused by oral ecological imbalance when cariogenic/aciduric bacteria obtain an ecological advantage. Compared with planktonic bacteria, dental plaques are difficult to remove under extracellular polymeric substance protection. In this study, the effect of caffeic acid phenethyl ester (CAPE) on a preformed cariogenic multi-species biofilm was evaluated, which was comprised of cariogenic bacteria (Streptococcus mutans), commensal bacteria (Streptococcus gordonii), and a pioneer colonizer (Actinomyces naeslundii). Our result revealed that treatment with 0.08 mg/mL CAPE reduced live S. mutans in the preformed multi-species biofilm while not significantly changing the quantification of live S. gordonii. CAPE significantly reduced the production of lactic acid, extracellular polysaccharide, and extracellular DNA and made the biofilm looser. Moreover, CAPE could promote the H2O2 production of S. gordonii and inhibit the expression of SMU.150 encoding mutacin to modulate the interaction among species in biofilms. Overall, our results suggested that CAPE could inhibit the cariogenic properties and change the microbial composition of the multi-species biofilms, indicating its application potential in dental caries prevention and management.

Therapeutic efficacy of caffeic acid phenethyl ester in cancer therapy: An updated review

Nowadays, there is a lot of public and scientific interest in using phytochemicals to treat human ailments. Existing cancer medicines still run across obstacles, despite significant advancements in the field. For instance, chemotherapy may result in severe adverse effects, increased drug resistance, and treatment failure. Natural substances that are phytochemically derived provide innovative approaches as potent therapeutic molecules for the treatment of cancer. Bioactive natural compounds may enhance chemotherapy for cancer by increasing the sensitivity of cancer cells to medicines. Propolis has been found to interfere with the viability of cancer cells, among other phytochemicals. Of all the components that make up propolis, caffeic acid phenethyl ester (CAPE) (a flavonoid) has been the subject of the most research. It demonstrates a broad spectrum of therapeutic uses, including antitumor, antimicrobial, antiviral, anti-inflammatory, immunomodulatory, hepatoprotective, neuroprotective, and cardioprotective effects. Studies conducted in vitro and in vivo have demonstrated that CAPE specifically targets genes involved in cell death, cell cycle regulation, angiogenesis, and metastasis. By altering specific signaling cascades, such as the NF-κB signaling pathway, CAPE can limit the proliferation of human cancer cells. This review highlights the research findings demonstrating the anticancer potential of CAPE with a focus on multitargeted molecular and biological implications in various cancer models.

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.

Taiwanese green propolis ameliorates metabolic syndrome via remodeling of white adipose tissue and modulation of gut microbiota in diet-induced obese mice

Excessive energy intake leads to dysbiosis of intestinal microbiota and puts surrounding tissues under oxidative stress and inflammation, contributing to the development of metabolic syndrome. Taiwanese green propolis (TGP) exhibits a broad spectrum of biological activities, including anti-bacterial, anti-inflammatory, and antioxidant properties. However, the benefits of TGP on metabolic syndrome have not been explained in detail. In this study, we examined the preventive effects of TGP on high-fat diet (HFD)-induced obesity. The results showed that TGP supplementation at 1000 ppm improved condition such as hyperlipidemia, fat accumulation, liver steatosis, and whitening of brown adipose tissue (BAT) in mice. In addition, we observed more cold-induced non-shivering thermogenesis by BAT in TGP treatment with 1000 ppm group. At lower dose of 500 ppm, TGP improved glucose intolerance and insulin insensitivity in HFD mice and restructured the composition of gut microbiota to reduce dysbiosis, which involved an increase in the abundance of metabolism-related bacteria such as Lachnospiraceae NK4A136 group and the decrease in Desulfovibrio. The change of dominant microbiota was associated with the homeostasis of blood glucose and lipid. Transcriptome and micro-western array analysis revealed that TGP supplementation at 500 ppm promoted the browning and adipogenesis in white adipose tissue (WAT), blocked inflammation signaling and attenuated reactive oxygen species, contributing to healthy WAT remodeling and offsetting negative metabolic effects of obesity. We concluded that TGP modulated the function of BAT, WAT, and gut microbiota, bringing a balance to the glucose and lipid homeostasis in the body.

Propolis polyphenols: A review on the composition and anti-obesity mechanism of different types of propolis polyphenols

Obesity, one of the most common nutritional diseases worldwide, can lead to dyslipidemia, high blood sugar, high blood pressure, and inflammation. Some drugs have been developed to ameliorate obesity. However, these drugs may cause serious side effects. Therefore, there is an urgent need for alternative “natural” remedies including propolis. Studies have found that propolis has excellent anti-obesity activity in in vitro and in vivo models during the past decades, of which polyphenols are the key component in regulating weight loss. This review focused on the different polyphenol compositions of propolis from different regions and plants, the evidence for the anti-obesity effects of different types of propolis and its derivatives, discussed the impact of propolis polyphenols on obesity related signal pathways, and proposed the molecular mechanism of how propolis polyphenols affect these signal pathways. For example, propolis and its derivatives regulate lipid metabolism related proteins, such as PPARα, PPARγ, SREBP-1&2, and HMG CoA etc., destroy the formation of CREB/CRTC2 transcription complex, activate Nrf2 pathway or inhibit protein kinase IKK ε/TBK1, thereby affecting fat production and lipid metabolism; The effects of propolis on adipokines (adiponectin, leptin and inflammatory factors) were discussed. Additionally, the mechanism of polyphenols in propolis promoting the browning of adipose tissues and the relationship between intestinal microorganisms was summarized. These information may be of value to better understand how specific propolis polyphenols interact with specific signaling pathways and help guide the development of new drugs to combat obesity and related metabolic diseases.

Ameliorative effects of propolis upon reproductive toxicity in males

Propolis is a sticky natural product produced by honeybees. Research studies have discussed the effectiveness of propolis, directly or indirectly, for ameliorating reproductive toxicity in males; however, this research has not yet been reviewed. The current paper presents an integrative summary of all research studies in Scopus and PubMed that investigated the effects of propolis on semen quality, and hence on male fertility, in conditions of reproductive toxicity. The consensus indicates that propolis ameliorates reproductive toxicity and enhances semen quality in vivo in test animals. These effects may be attributable to the ability of propolis to reduce testicular oxidative damage, enhance testicular antioxidant defense mechanisms, increase nitric oxide production, reduce testicular apoptotic injury, and boost testosterone production. However, to generalize these effects in humans would require further research.

Chemical Characterization, α-Glucosidase, α-Amylase and Lipase Inhibitory Properties of the Australian Honey Bee Propolis

The use of functional foods and nutraceuticals as a complementary therapy for the prevention and management of type 2 diabetes and obesity has steadily increased over the past few decades. With the aim of exploring the therapeutic potentials of Australian propolis, this study reports the chemical and biological investigation of a propolis sample collected in the Queensland state of Australia which exhibited a potent activity in an in vitro α-glucosidase inhibitory screening. The chemical investigation of the propolis resulted in the identification of six known prenylated flavonoids including propolins C, D, F, G, H, and solophenol D. These compounds potently inhibited the α-glucosidase and two other enzymes associated with diabetes and obesity, α-amylase, and lipase on in vitro and in silico assays. These findings suggest that this propolis is a potential source for the development of a functional food to prevent type 2 diabetes and obesity. The chemical analysis revealed that this propolis possessed a chemical fingerprint relatively similar to the Pacific propolis found in Okinawa (South of Japan), Taiwan, and the Solomon Islands. This is the first time the Pacific propolis has been identified in Australia.

Antibacterial and Antibiofilm Activities of Thailand Propolis Against Escherichia coli

Escherichia coli is an important bacterium for preventing food poisoning and biofilm infections. The emergence of antibiotic-resistant microorganisms necessitates the development of new antibiotics. The formation of bacterial biofilm is a drug-resistance mechanism utilized by diverse microorganisms. Therefore, it is important to identify compounds that can inhibit biofilm formation and cell survival, without triggering drug resistance. Herein, the antibacterial and antibiofilm activities of 2 types of Thai propolis (collected from Chiang Mai and Chanthaburi) against E. coli were investigated. The antibacterial activity was evaluated using the paper-disc method, while the minimum inhibitory concentration assay was performed using 2-fold serial dilution. Both types of Thai propolis and their isolated compounds showed antibacterial activity against E. coli (minimum inhibitory concentration: 32 µg/mL). The biofilm growth and development were assessed using a crystal violet solution. In particular, the extracts of the Chiang Mai propolis exhibited a significant antibiofilm formation activity against E. coli. Four prenylflavonoids, present in high proportions in the Chiang Mai propolis extracts, inhibited biofilm formation at low concentrations, contributing to the overall antibiofilm activity. These findings indicate that Thai propolis, a natural product, exhibits antibacterial and antibiofilm activities against E. coli.