Multifaceted roles of pollen in the management of cancer

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.

Automated summary

Oral drug delivery of microparticles has limitations such as aggregation, decreased loading capacity, and batch-to-batch variation, which hinders its scale-up. Porous structures have gained attention for their high loading capacity and ability to carry biomacromolecules, but non-uniform particle size distribution and the impact of porogen properties are challenges. To overcome these drawbacks, natural carriers like pollen are explored as drug delivery systems due to their ability to withstand harsh environments and exhibit uniform particle size distribution. Additionally, pollen contains phytoconstituents with various pharmacological applications. This review focuses on the microstructure, composition, and utility of pollen in cancer management, highlighting extraction strategies, characterization techniques, and the use of sporopollenin exine capsule for oral delivery of antineoplastic drugs. It also discusses emerging cancer treatments such as photothermal therapy, immunotherapy, and microrobots. The anticancer activity of pollen extract, regulatory perspective, bottlenecks, and future directions related to pollen are summarized.