Plant protein-based hydrophobic fine and ultrafine carrier particles in drug delivery systems

Abstract

For thousands of years, plants and their products have been used as the mainstay of medicinal therapy. In recent years, besides attempts to isolate the active ingredients of medicinal plants, other new applications of plant products, such as their use to prepare drug delivery vehicles, have been discovered. Nanobiotechnology is a branch of pharmacology that can provide new approaches for drug delivery by the preparation of biocompatible carrier nanoparticles (NPs). In this article, we review recent studies with four important plant proteins that have been used as carriers for targeted delivery of drugs and genes. Zein is a water-insoluble protein from maize; Gliadin is a 70% alcohol-soluble protein from wheat and corn; legumin is a casein-like protein from leguminous seeds such as peas; lectins are glycoproteins naturally occurring in many plants that recognize specific carbohydrate residues. NPs formed from these proteins show good biocompatibility, possess the ability to enhance solubility, and provide sustained release of drugs and reduce their toxicity and side effects. The effects of preparation methods on the size and loading capacity of these NPs are also described in this review.

Keywords: Plant; Sustained; delivery; drug; gliadin; lectin; legumin; nano-carrier; proteins; release; zein.

Figure 1

Structure of a single unit of zein

Figure 2

Schematic diagram for the apparatus and process of the solution enhanced dispersion by supercritical fluids (SEDS) technique; the apparatus consists of three major systems: a CO2 supply system, an organic solution delivery system, and a high pressure vessel. The components are: 1) CO2 cylinder, 2) cooling system, 3) piston pump, 4) heat exchanger, 5) HPLC pump, 6) solution, 7) high pressure Wessel, 8) back pressure regulator, 9) coaxial nozzle, 10) pressure meter, 11) gas bath.

Figure 3

Electrospinning setup consists of a spinneret (typically a hypodermic syringe needle) connectedto a high-voltage, direct current power supply, a syringe pump, and a grounded collector. A polymer solution, is loaded into the syringe and this liquid is extruded from the needle tip at a constant rate by a syringe pump A) single electrospinning B) coaxial electrospinning (A coaxial setup uses a multiple solution feed system which allows for the injection of one solution into another at the tip of the) spinneret.

Figure 4

Production of Legumin NPs by the coacervation method: First, the extracted plant legumin is purified by ion exchange chromatography; then, phosphate buffer as desolvating agent is added to the purified protein and finally, the generated protein NP coacervates are stabilized through crosslinking by glutaraldehyde.

Figure 5

Three main steps to target specific cells at epithelial barriers by lectins including: Binding, Internalization and Intracellular transport of lectins or lectin conjugates

Figure 6

Schematic for intestinal drug transport using WGA-conjugated lipid NPs targeted to intestinal mucosal cells: (a,c) fluid phase endocytosis, (b) binding of WGA to glycoproteins followed by receptor-mediated endocytosis, (d) transcellular transport, (e) endocytosis might be blocked by absence of receptors or unsuitable conditions