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International Journal of Pharmaceutics Aug 2023Oral drug delivery of microparticles demonstrates shortcomings like aggregation, decreased loading capacity and batch-to-batch variation, which limits its scale-up.... (Review)
Review
Oral drug delivery of microparticles demonstrates shortcomings like aggregation, decreased loading capacity and batch-to-batch variation, which limits its scale-up. Later, porous structures gained attention because of their large surface-to-volume ratio, high loading capacity and ability to carry biomacromolecules, which undergo degradation in GIT. But there are pitfalls like non-uniform particle size distribution, the impact of porogen properties, and harsh chemicals. To circumvent these drawbacks, natural carriers like pollen are explored in drug delivery, which withstands harsh environments. This property helps to subdue the acid-sensitive drug in GIT. It shows uniform particle size distribution within the species. On the other side, they contain phytoconstituents like flavonoids and polysaccharides, which possess various pharmacological applications. Therefore, pollen has the capability as a carrier system and therapeutic agent. This review focuses on pollen's microstructure, composition and utility in cancer management. The extraction strategies, characterisation techniques and chemical structure of sporopollenin exine capsule, its use in the oral delivery of antineoplastic drugs, and emerging cancer treatments like photothermal therapy, immunotherapy and microrobots have been highlighted. We have mentioned a note on the anticancer activity of pollen extract. Further, we have summarised the regulatory perspective, bottlenecks and way forward associated with pollen.
Topics: Pollen; Biopolymers; Drug Delivery Systems; Neoplasms
PubMed: 37516214
DOI: 10.1016/j.ijpharm.2023.123278 -
Current Topics in Developmental Biology 2019With the origin of pollination in ancient seed plants, the male gametophyte ("pollen") began to evolve a new and unique life history stage, the progamic phase, a... (Review)
Review
With the origin of pollination in ancient seed plants, the male gametophyte ("pollen") began to evolve a new and unique life history stage, the progamic phase, a post-pollination period in which pollen sexual maturation occurs in interaction with sporophyte-derived tissues. Pollen performance traits mediate the timing of the fertilization process, often in competition with other pollen, via the speed of pollen germination, sperm development, and pollen tube growth. Studies of pollen development rarely address the issue of performance or its evolution, which involves linking variation in developmental rates to relative fitness within populations or to adaptations on a macroevolutionary scale. Modifications to the pollen tube pathway and changes in the intensity of pollen competition affect the direction and strength of selection on pollen performance. Hence, pollen developmental evolution is always contextual-it involves both the population biology of pollen reaching stigmas and the co-evolution of sporophytic traits, such as the pollen tube pathway and mating system. For most species, performance evolution generally reflects a wandering history of periods of directional selection and relaxed selection, channeled by developmental limitations, a pattern that favors the accumulation of diversity and redundancy in developmental mechanisms and the genetic machinery. Developmental biologists are focused on finding universal mechanisms that underlie pollen function, and these are largely mechanisms that have evolved through their effects on performance. Here, we suggest ways in which studies of pollen performance or function could progress by cross-fertilization between the "evo" and "devo" fields.
Topics: Biological Evolution; Gametogenesis, Plant; Plant Physiological Phenomena; Plants; Pollen
PubMed: 30612621
DOI: 10.1016/bs.ctdb.2018.11.012 -
Plant Reproduction Jun 2016Pollen development and stress. In angiosperms, pollen or pollen grain (male gametophyte) is a highly reduced two- or three-cell structure which plays a decisive role in... (Review)
Review
Pollen development and stress. In angiosperms, pollen or pollen grain (male gametophyte) is a highly reduced two- or three-cell structure which plays a decisive role in plant reproduction. Male gametophyte development takes place in anther locules where diploid sporophytic cells undergo meiotic division followed by two consecutive mitotic processes. A desiccated and metabolically quiescent form of mature pollen is released from the anther which lands on the stigma. Pollen tube growth takes place followed by double fertilization. Apart from its importance in sexual reproduction, pollen is also an interesting model system which integrates fundamental cellular processes like cell division, differentiation, fate determination, polar establishment, cell to cell recognition and communication. Recently, pollen functionality has been studied by multidisciplinary approaches which also include OMICS analyses like transcriptomics, proteomics and metabolomics. Here, we review recent advances in proteomics of pollen development and propose the process of developmental priming playing a key role to guard highly sensitive developmental processes.
Topics: Heat-Shock Response; Hot Temperature; Pollen; Proteomics; Stress, Physiological
PubMed: 27271282
DOI: 10.1007/s00497-016-0283-9 -
Planta Aug 2011Vacuoles of several types can be observed in pollen throughout its development. Their physiological significance reflects the complexity of the biological process... (Review)
Review
Vacuoles of several types can be observed in pollen throughout its development. Their physiological significance reflects the complexity of the biological process leading to functional pollen grains. Vacuolisation always occurs during pollen development but when ripe pollen is shed the extensive translucent vacuoles present in the vegetative parts in previous stages are absent. Vacuole functions vary according to developmental stage but in ripe pollen they are mainly storage sites for reserves. Vacuoles cause pollen to increase in size by water accumulation and therefore confer some degree of resistance to water stress. Modalities of vacuolisation occur in pollen in the same manner as in other tissues. In most cases, autophagic vacuoles degrade organelles, as in the microspore after meiosis, and can be regarded as cytoplasm clean-up following the transition from the diploid sporophytic to the haploid gametophytic state. This also occurs in the generative cell but not in sperm cells. Finally, vacuoles have a function when microspores are used for pollen embryogenesis in biotechnology being targets for stress induction and afterwards contributing to cytoplasmic rearrangement in competent microspores.
Topics: Pollen; Stress, Physiological; Vacuoles
PubMed: 21706335
DOI: 10.1007/s00425-011-1462-4 -
Allergy Proceedings : the Official... 1990Pollens in Florida are most numerous in January through March and approximately 82% are tree pollens. Two of the most common trees, southern red cedar and laurel oak, do... (Review)
Review
Pollens in Florida are most numerous in January through March and approximately 82% are tree pollens. Two of the most common trees, southern red cedar and laurel oak, do not have commercial extracts. There are relatively low pollen counts for grasses and weeds, but the season is prolonged. The low counts do not indicate that these are not important allergens since in Florida children with allergies show a high reactivity rate to these allergens. Numerous grasses that are wind-pollinated and possible allergens have not been studied. In the Urticaceae family, there is no extract for Parietaria floridana. Acalypha has not been evaluated in this region and is also present in the air surveys using more efficient sampling techniques.
Topics: Florida; Humans; Poaceae; Pollen; Seasons; Trees
PubMed: 2292374
DOI: 10.2500/108854190778879747 -
Biomolecules Jan 2020Pollen is recognized as an excellent dietary supplement for human nutrition, which is why it can be found in different forms on the market (granules, capsules, tablets,... (Review)
Review
Pollen is recognized as an excellent dietary supplement for human nutrition, which is why it can be found in different forms on the market (granules, capsules, tablets, pellets, and powders). But, the digestibility of pollen's nutrients is strongly affected by the presence of a pollen shell, which can decrease the bioavailability of nutrients by 50% and more. Since consumers have become more aware of the benefits of a healthy diet and the necessity to improve pollen digestibility, different pollen-based functional food products have been developed and extensive studies were done to estimate the beneficial effects of pollen-based feed on animal growth, health, and rigor mortise stage. Considering the positive effects of pollen nutrients and phytometabolites on human and animal health, the aim of this paper was to give an overview of recent achievements in the application of pollen in the formulation of functional food and animal diets. Special attention was paid to the effects of pollen's addition on the nutritional, functional, techno-functional, and sensory properties of the new formulated food products. Anti-nutritional properties of pollen were also discussed. This review points out the benefits of pollen addition to food and feed and the possible directions in the further development of functional food and feed for the wellbeing of everyone.
Topics: Animal Feed; Animals; Biological Availability; Diet; Dietary Supplements; Food Additives; Functional Food; Humans; Pollen
PubMed: 31948037
DOI: 10.3390/biom10010084 -
Current Opinion in Allergy and Clinical... Feb 2015The aim of the present review was to discuss the effects of pollen components on innate immune responses. (Review)
Review
PURPOSE OF REVIEW
The aim of the present review was to discuss the effects of pollen components on innate immune responses.
RECENT FINDINGS
Pollens contain numerous factors that can stimulate an innate immune response. These include intrinsic factors in pollens such as nicotinamide adenine dinucleotide phosphate oxidases, proteases, aqueous pollen proteins, lipids, and antigens. Each component stimulates innate immune response in a different manner. Pollen nicotinamide adenine dinucleotide phosphate oxidases induce reactive oxygen species generation and recruit neutrophils that stimulate subsequent allergic inflammation. Pollen proteases damage epithelial barrier function and increase antigen uptake. Aqueous pollen extract proteins and pollen lipids modulate dendritic cell function and induce Th2 polarization. Clinical studies have shown that modulation of innate immune response to pollens with toll-like receptor 9- and toll-like receptor 4-stimulating conjugates is well tolerated and induces clear immunological effects, but is not very effective in suppressing primary clinical endpoints of allergic inflammation.
SUMMARY
Additional research on innate immune pathways induced by pollen components is required to develop novel strategies that will mitigate the development of allergic inflammation.
Topics: Animals; Antigens, Plant; Humans; Immunity, Innate; NADH, NADPH Oxidoreductases; Neutrophils; Pollen; Reactive Oxygen Species; Rhinitis, Allergic, Seasonal; Th2 Cells
PubMed: 25546327
DOI: 10.1097/ACI.0000000000000136 -
Sexual Plant Reproduction Mar 2010Many species of Rosaceae, Solanaceae, and Plantaginaceae exhibit S-RNase-based self-incompatibility (SI) in which pistil-part specificity is controlled by S... (Review)
Review
Many species of Rosaceae, Solanaceae, and Plantaginaceae exhibit S-RNase-based self-incompatibility (SI) in which pistil-part specificity is controlled by S locus-encoded ribonuclease (S-RNase). Although recent findings revealed that S locus-encoded F-box protein, SLF/SFB, determines pollen-part specificity, how these pistil- and pollen-part S locus products interact in vivo and elicit the SI reaction is largely unclear. Furthermore, genetic studies suggested that pollen S function can differ among species. In Solanaceae and the rosaceous subfamily Maloideae (e.g., apple and pear), the coexistence of two different pollen S alleles in a pollen breaks down SI of the pollen, a phenomenon known as competitive interaction. However, competitive interaction seems not to occur in the subfamily Prunoideae (e.g., cherry and almond) of Rosaceae. Furthermore, the effect of the deletion of pollen S seems to vary among taxa. This review focuses on the potential differences in pollen-part function between subfamilies of Rosaceae, Maloideae, and Prunoideae, and discusses implications for the mechanistic divergence of the S-RNase-based SI.
Topics: F-Box Proteins; Flowers; Gene Expression Regulation, Plant; Inbreeding; Plant Proteins; Pollen; Ribonucleases; Rosaceae; Species Specificity
PubMed: 20165962
DOI: 10.1007/s00497-009-0111-6 -
Food Research International (Ottawa,... Feb 2024Bee pollen is hailed as a treasure trove of human nutrition and has progressively emerged as the source of functional food and medicine. This review conducts a... (Review)
Review
Bee pollen is hailed as a treasure trove of human nutrition and has progressively emerged as the source of functional food and medicine. This review conducts a compilation of nutrients and phytochemicals in bee pollen, with particular emphasis on some ubiquitous and unique phenolamides and flavonoid glycosides. Additionally, it provides a concise overview of the diverse health benefits and therapeutic properties of bee pollen, particularly anti-prostatitis and anti-tyrosinase effects. Furthermore, based on the distinctive structural characteristics of pollen walls, a substantial debate has persisted in the past concerning the necessity of wall-disruption. This review provides a comprehensive survey on the necessity of wall-disruption, the impact of wall-disruption on the release and digestion of nutrients, and wall-disruption techniques in industrial production. Wall-disruption appears effective in releasing and digesting nutrients and exploiting bee pollen's bioactivities. Finally, the review underscores the need for future studies to elucidate the mechanisms of beneficial effects. This paper will likely help us gain better insight into bee pollen to develop further functional foods, personalized nutraceuticals, cosmetics products, and medicine.
Topics: Bees; Humans; Animals; Pollen; Nutrients; Flavonoids; Glycosides; Phytochemicals
PubMed: 38309905
DOI: 10.1016/j.foodres.2024.113934 -
International Review of Cell and... 2019In flowering plants, sexual reproduction is actively regulated by cell-cell communication between the male pollen and female pistil, and many species possess... (Review)
Review
In flowering plants, sexual reproduction is actively regulated by cell-cell communication between the male pollen and female pistil, and many species possess self-incompatibility systems for the selective rejection of self-pollen to maintain genetic diversity. The Brassicaceae self-incompatibility pathway acts early on when pollen grains have landed on the stigmatic papillae at the top of the pistil. Extensive studies have revealed that self-pollen rejection in the Brassicaceae is initiated by an S-haplotype-specific interaction between two polymorphic proteins: the pollen S-locus protein 11/S cysteine-rich (SP11/SCR) ligand and the stigma S receptor kinase (SRK). While the different S-haplotypes are typically codominant, there are several examples of dominant-recessive interactions, and a small RNA-based regulation of SP11/SCR expression has been uncovered as a mechanism behind these genetic interactions. Recent research has also added to our understanding of various cellular components in the pathway leading from the SP11/SCR-SRK interaction, including two signaling proteins, the M-locus protein kinase (MLPK) and the ARM-repeat containing 1 (ARC1) E3 ligase, as well as calcium fluxes and induction of autophagy in the stigmatic papillae. Finally, a better understanding of the compatible pollen responses that are targeted by the self-incompatibility pathway is starting to emerge, and this will allow us to more fully understand how the Brassicaceae self-incompatibility pathway causes self-pollen rejection. Here, we provide an overview of the field, highlighting recent contributions to our understanding of Brassicaceae self-incompatibility, and draw comparisons to a recently discovered unilateral incompatibility system.
Topics: Brassicaceae; Pollen; Self-Incompatibility in Flowering Plants; Signal Transduction
PubMed: 30712670
DOI: 10.1016/bs.ircmb.2018.05.011