Phytochemical content, especially spermidine derivatives, presenting antioxidant and antilipoxygenase activities in Thai bee pollens

A guide to sunflowers: floral resource nutrition for bee health and key pollination syndromes

Sunflower, Helianthus annuus L., is a prominent global oilseed crop with rising cultivation and appeal as a bee-friendly plant by providing abundant floral resources for pollinators. Mass-flowering crops can increase the availability of resources, and sunflower is a good opportunity to relieve pollen scarcity during the late summer in agricultural landscapes. Yet this should be taken with caution as they also provide a homogeneous source of nutrition. This study aimed to review and summarize the nutritional profile of sunflower pollen, nectar, bee bread, and honey, while assessing their effects on bee survival, development, and health. Furthermore, we present here the general state of knowledge on additional pollinator syndromes that extend beyond floral resources, including those influencing pollinator visual and olfactory attraction. We found that while sunflower pollen's nutritional quality is questioned due to lower protein and amino acid deficiencies, its nutrient content, like nectar sugars, had large variability. Sunflower pollen consumption showed mixed effects on Apis mellifera and Bombus species, sometimes negatively impacting development and survival. However, studies have conveyed a positive impact on bee health as sunflower pollen consistently reduced the infection intensity of the gut parasite, Crithidia bombi, in Bombus species. This probes the question on defining the quality of floral resources, emphasizing the need for caution when categorizing sunflower as a low quality nutritional resource. This review also outlines the importance of sunflower nectar characteristics (sugar content and volume) and floral morphology (flower pigmentation and corolla length) on pollinator foraging preferences. A prominent knowledge gap persists regarding nectar chemistry and sunflowers' extensive volatile profile to better understand the pollination syndromes that drive its pollinator interactions.

Changes in Ascorbic Acid, Phenolic Compound Content, and Antioxidant Activity In Vitro in Bee Pollen Depending on Storage Conditions: Impact of Drying and Freezing

Bee pollen (BP) is a very valuable bee product, and its value depends on its proteins, lipids, amino acids, carbohydrates, vitamins, minerals, and biologically active compounds such as phenolic compounds, which may change depending on the method of pollen preparation after collection and its storage conditions. Therefore, it is very important to determine when the decline in bioactive compounds in BP occurs during storage. The purpose of this study was to evaluate the changes in the content of ascorbic acid and phenolic compounds, and to determine the antioxidant activity of BP extracts depending on their preparation method and storage conditions over a 15-month period, with assessments conducted every 3 months. Dried pollen (at +28 °C on the first day and +35 °C on the second day) and frozen (-20 °C and -80 °C) BP samples were prepared. After 3 months of storage, there was no decrease of ascorbic acid in frozen BP; however, it decreased by 20% in dried BP (p < 0.05). It was determined that in frozen BP, the content of total phenolic compounds decreased by 12-14% (p < 0.05) after 6 months, and in dried BP, it decreased by 7% (p < 0.05) after 3 months. The levels of flavonoids decreased by 10-17% (p < 0.05) in BP after 6 months. Chlorogenic and p-coumaric acids have been observed as the most abundant phenolic acids in BP. During storage (the 6-15-month period), the strongest antiradical and reducing activity in vitro was estimated in the frozen (-80 °C) BP, which was 1.8-3.4-fold and 2.6-3.1-fold higher, respectively, compared to the dried BP extracts. In conclusion, significant results were obtained, showing better stability of phenolic compounds and ascorbic acid during storage in frozen BP compared to dried pollen. Melisopalynological analysis revealed a polyfloral pollen mixture, with Salix spp. and Brassica napus L. predominating in all samples, comprising 34.3% and 36.8%, respectively. Among these, Acer platanoides L., Malus domestica Borkh., and Taraxacum officinale L. were important minor pollens present in the samples examined.

Bee Pollen as a Source of Biopharmaceuticals for Neurodegeneration and Cancer Research: A Scoping Review and Translational Prospects

Bee Pollen (BP) has many advantageous properties relying on its multitargeting potential, a new tendency in managing many challenging illnesses. In cancer and neurodegeneration, the multiple effects of BP could be of unequaled importance and need further investigation. Although still limited, available data interestingly spotlights some floral sources with promising activities in line with this investigation. Adopting scoping review methodology, we have identified many crucial bioactivities that are widely recognized to individual BP compounds but remain completely untapped in this valuable bee cocktail. A wide range of these compounds have been recently found to be endowed with great potential in modulating pivotal processes in neurodegeneration and cancer pathophysiology. In addition, some ubiquitous BP compounds have only been recently isolated, while the number of studied BPs remains extremely limited compared to the endless pool of plant species worldwide. We have also elucidated that clinical profits from these promising perspectives are still impeded by challenging hurdles such as limited bioavailability of the studied phytocompounds, diversity and lack of phytochemical standardization of BP, and the difficulty of selective targeting in some pathophysiological mechanisms. We finally present interesting insights to guide future research and pave the way for urgently needed and simplified clinical investigations.

Chemical Properties and Biological Activity of Bee Pollen

Pollen, a remarkably versatile natural compound collected by bees for its abundant source of proteins and nutrients, represents a rich reservoir of diverse bioactive compounds with noteworthy chemical and therapeutic potential. Its extensive biological effects have been known and exploited since ancient times. Today, there is an increased interest in finding natural compounds against oxidative stress, a factor that contributes to various diseases. Recent research has unraveled a multitude of biological activities associated with bee pollen, ranging from antioxidant, anti-inflammatory, antimicrobial, and antifungal properties to potential antiviral and anticancer applications. Comprehending the extensive repertoire of biological properties across various pollen sources remains challenging. By investigating a spectrum of pollen types and their chemical composition, this review produces an updated analysis of the bioactive constituents and the therapeutic prospects they offer. This review emphasizes the necessity for further exploration and standardization of diverse pollen sources and bioactive compounds that could contribute to the development of innovative therapies.

Unraveling the Antioxidant Activity of 2R,3R-dihydroquercetin

It has been reported that in an oxidative environment, the flavonoid 2R,3R-dihydroquercetin (2R,3R-DHQ) oxidizes into a product that rearranges to form quercetin. As quercetin is a very potent antioxidant, much better than 2R,3R-DHQ, this would be an intriguing form of targeting the antioxidant quercetin. The aim of the present study is to further elaborate on this targeting. We can confirm the previous observation that 2R,3R-DHQ is oxidized by horseradish peroxidase (HRP), with H2O2 as the oxidant. However, HPLC analysis revealed that no quercetin was formed, but instead an unstable oxidation product. The inclusion of glutathione (GSH) during the oxidation process resulted in the formation of a 2R,3R-DHQ-GSH adduct, as was identified using HPLC with IT-TOF/MS detection. GSH adducts appeared on the B-ring of the 2R,3R-DHQ quinone, indicating that during oxidation, the B-ring is oxidized from a catechol to form a quinone group. Ascorbate could reduce the quinone back to 2R,3R-DHQ. No 2S,3R-DHQ was detected after the reduction by ascorbate, indicating that a possible epimerization of 2R,3R-DHQ quinone to 2S,3R-DHQ quinone does not occur. The fact that no epimerization of the oxidized product of 2R,3R-DHQ is observed, and that GSH adducts the oxidized product of 2R,3R-DHQ on the B-ring, led us to conclude that the redox-modulating activity of 2R,3R-DHQ quinone resides in its B-ring. This could be confirmed by chemical calculation. Apparently, the administration of 2R,3R-DHQ in an oxidative environment does not result in 'biotargeting' quercetin.

Translational Research on Bee Pollen as a Source of Nutrients: A Scoping Review from Bench to Real World

The emphasis on healthy nutrition is gaining a forefront place in current biomedical sciences. Nutritional deficiencies and imbalances have been widely demonstrated to be involved in the genesis and development of many world-scale public health burdens, such as metabolic and cardiovascular diseases. In recent years, bee pollen is emerging as a scientifically validated candidate, which can help diminish conditions through nutritional interventions. This matrix is being extensively studied, and has proven to be a very rich and well-balanced nutrient pool. In this work, we reviewed the available evidence on the interest in bee pollen as a nutrient source. We mainly focused on bee pollen richness in nutrients and its possible roles in the main pathophysiological processes that are directly linked to nutritional imbalances. This scoping review analyzed scientific works published in the last four years, focusing on the clearest inferences and perspectives to translate cumulated experimental and preclinical evidence into clinically relevant insights. The promising uses of bee pollen for malnutrition, digestive health, metabolic disorders, and other bioactivities which could be helpful to readjust homeostasis (as it is also true in the case of anti-inflammatory or anti-oxidant needs), as well as the benefits on cardiovascular diseases, were identified. The current knowledge gaps were identified, along with the practical challenges that hinder the establishment and fructification of these uses. A complete data collection made with a major range of botanical species allows more robust clinical information.

In-depth investigation of the hypoglycemic mechanism of Morchella importuna polysaccharide via metabonomics combined with 16S rRNA sequencing

Increasing evidence indicates that type 2 diabetes mellitus (T2DM) is closely related to intestinal bacteria disorders and abnormal hepatic metabolism. Morchella importuna polysaccharide (MIP) shows excellent hypoglycemic activity in vitro. However, the hypoglycemic effect and mechanism of MIP in vivo have yet to be investigated. In this study, the blood glucose, blood lipid and insulin resistance of diabetic mice after MIP intervention were measured to evaluate its hypoglycemic effect. Then, the microbiome and metabolomics were combined to explore the hypoglycemic mechanism of MIP. Results indicated that high dose MIP (400 mg/kg) had significant hypoglycemic effect. Furthermore, MIP could reverse diabetes-induced intestinal disorder by increasing the abundance of Akkermansia, Blautia, Dubosiella, and Lachnospiraceae, as well as decreasing the abundance of Helicobacteraceae. Besides, the hepatic metabolites and complex network systems formed by multiple metabolic pathways were regulated after MIP treatment. Notably, a new biomarker of diabetes (N-P-coumaroyl spermidine) was discovered in this study. Moreover, the significant association between intestinal bacteria and hepatic metabolites was determined by correlations analysis, which in turn confirmed MIP alleviated T2DM via the gut-liver axis. Therefore, these findings elucidated in-depth hypoglycemic mechanisms of MIP and provided a new biomarker for the prevention of diabetes.