nutrients Review Bee Pollen: Current Status and Therapeutic Potential Shaden A. M. Khalifa 1,*, Mohamed H. Elashal 2, Nermeen Yosri 2,3 , Ming Du 4 , Syed G. Musharraf 5, Lutfun Nahar 6 , Satyajit D. Sarker 7, Zhiming Guo 3 , Wei Cao 8, Xiaobo Zou 3, Aida A. Abd El-Wahed 9 , Jianbo Xiao 10 , Hany A. Omar 11 , Mohamed-Elamir F. Hegazy 12 and Hesham R. El-Seedi 2,13,14,* 1 Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden 2 Department of Chemistry, Faculty of Science, Menoufia University, Shebin El-Kom 32512, Egypt; [email protected] (M.H.E.); [email protected]fia.edu.eg (N.Y.) 3 School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China; [email protected] (Z.G.); [email protected] (X.Z.) 4 School of Food Science and Technology, National Engineering Research Center of Seafood, Dalian Polytechnic University, Dalian 116024, China; [email protected] 5 H.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan; [email protected] 6 Laboratory of Growth Regulators, Institute of Experimental Botany ASCR & Palacký University, Šlechtitel ˚u27, 78371 Olomouc, Czech Republic; [email protected] 7 Centre for Natural Products Discovery (CNPD), School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, James Parsons Building, Byrom Street, Liverpool L3 3AF, UK; [email protected] 8 College of Food Science and Technology, Northwest University, Xi’an 710069, China; [email protected] 9 Department of Bee Research, Plant Protection Research Institute, Agricultural Research Centre, Giza 12627, Egypt; [email protected] 10 Nutrition and Bromatology Group, Department of Analytical Chemistry and Food Science, Faculty of Food Citation: Khalifa, S.A.M.; Elashal, Science and Technology, University of Vigo—Ourense Campus, E-32004 Ourense, Spain; [email protected] 11 M.H.; Yosri, N.; Du, M.; Musharraf, College of Pharmacy, University of Sharjah, Sharjah, P.O.Box 27272, United Arab Emirates; [email protected] S.G.; Nahar, L.; Sarker, S.D.; Guo, Z.; 12 Chemistry of Medicinal Plants Department, National Research Centre, 33 El-Bohouth St., Dokki, Cao, W.; Zou, X.; et al. Bee Pollen: Giza 12622, Egypt; [email protected] Current Status and Therapeutic 13 International Research Center for Food Nutrition and Safety, Jiangsu University, Zhenjiang 212013, China Potential. Nutrients 2021, 13, 1876. 14 Pharmacognosy Group, Department of Pharmaceutical Biosciences, Biomedical Centre, Uppsala University, https://doi.org/10.3390/nu13061876 Box 591, SE-751 24 Uppsala, Sweden * Correspondence: [email protected] (S.A.M.K.); [email protected] (H.R.E.-S.); Academic Editors: Tel.: +46-700-101-113 (S.A.M.K.); +46-700-434-343 (H.R.E.-S.) Christina Chrysohoou and Konstantinos Tsioufis Abstract: Bee pollen is a combination of plant pollen and honeybee secretions and nectar. The Bible and ancient Egyptian texts are documented proof of its use in public health. It is considered a gold Received: 7 May 2021 mine of nutrition due to its active components that have significant health and medicinal properties. Accepted: 28 May 2021 Bee pollen contains bioactive compounds including proteins, amino acids, lipids, carbohydrates, Published: 31 May 2021 minerals, vitamins, and polyphenols. The vital components of bee pollen enhance different bodily functions and offer protection against many diseases. It is generally marketed as a functional food Publisher’s Note: MDPI stays neutral with affordable and inexpensive prices with promising future industrial potentials. This review with regard to jurisdictional claims in highlights the dietary properties of bee pollen and its influence on human health, and its applications published maps and institutional affil- in the food industry. iations. Keywords: bee pollen; metabolic syndromes; human health; functional food; nutritional value Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. 1. Introduction This article is an open access article distributed under the terms and In ancient societies, mainly in Greece, China, and Egypt, bee products were widely conditions of the Creative Commons used in medicine. The ancient Egyptians portray pollen as “a life-giving dust” [1]. Bee Attribution (CC BY) license (https:// pollen (Figure1) is a mixture of flower pollen with honeybee secretions and nectar. It creativecommons.org/licenses/by/ can be gathered at the entrance of the hives with the aid of traps (Figure1)[ 2]. Bee 4.0/). pollen is used in diets as supplementary nutrition due to its beneficial actions against Nutrients 2021, 13, 1876. https://doi.org/10.3390/nu13061876 https://www.mdpi.com/journal/nutrients Nutrients 2021, 13, x FOR PEER REVIEW 2 of 15 be gathered at the entrance of the hives with the aid of traps (Figure 1) [2]. Bee pollen is Nutrients 2021, 13, 1876 used in diets as supplementary nutrition due to its beneficial actions against human2 of 15 diseases. It is a potential source of vital nutrients like proteins, lipids, vitamins, minerals, and carbohydrates, as well as trace elements and considerable amounts of polyphenols, mainlyhuman flavonoids diseases. [3]. It Plant is a potential and geographical source of vitalorigins nutrients besides like other proteins, factors lipids,like atmos- vitamins, phericminerals, conditions, and soil carbohydrates, nature, and behavior as well asof tracethe bees elements affects andbee pollen considerable chemical amounts com- of positionpolyphenols, [4,5]. mainly flavonoids [3]. Plant and geographical origins besides other factors likeThe atmospheric current review conditions, aims to soil provide nature, an and overview behavior of thethe beesdietary affects properties bee pollen of chemicalbee pollencomposition and its impact [4,5]. on human health and recent applications in the food industry. Figure 1. Bee pollen traps and multi-flora bee pollen. Figure 1. BeeThe pollen current traps review and multi aims-flora to provide bee pollen an overview. of the dietary properties of bee pollen and its impact on human health and recent applications in the food industry. 2. Metabolites of Bee Pollen 2.Bee Metabolites pollen metabolites of Bee Pollen including; proteins, amino acids, enzymes, co-enzymes, carbohydrates,Bee pollen lipids, metabolites fatty acids, including; phenolic proteins, compounds, amino acids, bio enzymes,-elements, co-enzymes, and vitamins carbohy- (Figuredrates,s 2 lipids,and 3) fatty [6]. acids,The mean phenolic percent compounds, of protein bio-elements, in pollen and isvitamins 22.7%, including (Figures2 and vital3 )[6]. aminoThe acids mean such percent as tryptophan, of protein inphenylalanine, pollen is 22.7%, methionine, including vitalleucine, amino lysine, acids threonine, such as tryp- histidine,tophan, isoleucine, phenylalanine, and valine. methionine, These ami leucine,no acids lysine, are not threonine, synthesized histidine, in our isoleucine,bodies, but and theyvaline. play an These important amino role acids in optimal are not growth synthesized and health. in our bodies,And for but their they vital play engagement an important in generole expression, in optimal growthcell signaling and health. pathways, And fordigestion, their vital and engagement nutrient absorption, in gene expression, they mustcell be signalingincluded pathways,in the diet digestion,[7]. Nucleic and acids, nutrient particularly absorption, ribonucleic they must acid, be are included present in the in considerablediet [7]. Nucleic amounts. acids, As particularly a source ribonucleicof energy, acid,carbohydrates are present exist in considerable in bee pollen amounts. at 30.8%,As containing a source of reducing energy, carbohydrates sugars like glucose exist in and bee fructose pollen at [8] 30.8%,. About containing 5.1% of lipids reducing are sug- foundars in like bee glucose pollen and as fructoseessential [8fatty]. About acids 5.1% like of archaic, lipids arelinoleic, found and in bee γ- pollenlinoleic as acids, essential phospholipids,fatty acids likeand archaic, phytosterols linoleic, (in and particularγ-linoleic β acids,-sitosterol) phospholipids, [9]. Phenolic and compounds phytosterols (in representparticular an averageb-sitosterol) of 1.6% [9]. of Phenolic pollen content, compounds including represent leukotrienes, an average catechins, of 1.6% ofphe- pollen noliccontent, acids (e.g including., chlorogenic leukotrienes, acid), and catechins, flavonoids phenolic (e.g., kaempferol, acids (e.g., chlorogenicisorhamnetin, acid), and and quercetin)flavonoids [10]. (e.g., kaempferol, isorhamnetin, and quercetin) [10]. The Theessential essential substances, substances, including including vitamins vitamins and andbio-elements, bio-elements, are present are present in 0.7% in 0.7% of of the wholethe whole material. material. Bee pollen Bee pollen is a potential is a potential source source of fat- ofsoluble fat-soluble vitamins vitamins like vitamin like vitamin E, pro-vitaminE, pro-vitamin A, vitamin A, vitaminD, and water D, and-soluble water-soluble vitamins vitaminssuch as vitamins such as B1, vitamins B2, B6, B1,and B2,C, B6, also anda source C, also of a sourceacids oflike acids biotin, like rutin, biotin, pantothenic, rutin, pantothenic, nicotinic, nicotinic, inositol, inositol, and andfolic. folic. Bio-elementsBio-elements include include macro macro-elements-elements like like sodium, sodium, magnesium, magnesium, calci calcium,um,