Table 3:

Studies in which EVs have been used as carriers of natural compounds (EVs as drug carriers).

Study type	EV type	EV source	Isolation method	Incorporated natural agent	Context/condition	Expected EV advantages	Outcomes	Ref.
In vitro	Membrane vesicles (1 nm–3 μm)	Broccoli root (Brassica oleracea)	Two-phase aqueous polymer technique	Dyes: Basic fuchsin Bromophenol Fluorescents: Fluorescein Diacetate (FDA)	Transdermal delivery	• Hydrophobic properties • Availability • Stability • Permeability • Enhanced delivery	• Successful interaction with skin keratinocytes and delivery of loaded agents	(109)
In vitro	Exosomes	Cancer cell lines (MCF7, HepG2, Caco2 and PC3)	Commercial isolation kit	Bioactive saponins and flavonoids from black bean extract	Treatment of cancer cells	Enhanced uptake and delivery of the loaded compounds	• Better anti-proliferative and cytotoxic effects when loaded into exosomes	(104)
In vitro, In vivo	Exosomes	Naïve macrophages	Gradient ultra-centrifugation	Endogenous agent: Brain-derived neurotropic factor (BDNF)	Presence / absence of brain inflammation	• Efficient homing • BBB crossing • Enhanced delivery of the protein cargo	• Receptor-mediated endocytosis • Efficient BBB passing through LFA-1/ICAM-1 interactions • Better uptake in the presence of inflammation	(108)
In vivo (C57BL/6j)	Exosomes	Mouse lymphoma cell line (EL-4)	Differential centrifugation + sucrose gradient isolation	Anti-inflammatory agents: Curcumin / Stat3 inhibitor (JSI124)	Three models of brain inflammation: -LPS-induced -EAE -GL-26 brain tumor	• Selective uptake by microglial cells • Increased solubility, stability and bioavailability	• Exosome-encapsulated curcumin was efficiently delivered and ameliorated all three inflammation models	(107)
In vitro, In vivo	Exosomes	EL-4 and murine macrophage cells (RAW 264.7)	Differential centrifugation + sucrose gradient isolation	Curcumin	LPS-induced septic shock	• Inflammatory cell targeting • Reduced off-target delivery / toxicity • Enhanced stability in vitro and bioavailability in vivo	• Septic shock amelioration • Reduced population of CD11b+Gr-1+ cells • Successful delivery to circulating myeloid cells and apoptosis induction • Enhanced anti-inflammatory activity compared to curcumin alone	(106)
In vitro, In vivo	MVs	RBCs	RBC osmotic hemolysis and subsequent extrusion through 0.4μm polycarbonate membranes	Hydrophobic natural alkaloid: Camptothecin	BALB/c tumor models and lung carcinoma cells (A549)	• Reduced off-target toxicity • Overcoming low bioavailability due to hydrophobic nature • Overcoming immune-mediated clearance as opposed to synthetic carriers • Stability and retention (slow release)	• Efficient apoptotic and cytotoxic effects in tumor cells • Promising delivery to the tumor site • Optimal for theranostic applications	(105)
In vitro, In vivo	EVs (NS)	IC21 macrophages	Gradient ultra-centrifugation	TPP1 enzyme	Batten disease models: LINCL mice and TPP1 enzyme-deficient cells (CLN2)	• Brain homing • Immune inertness • Efficacious delivery • Protection against proteolytic degradation	• Therapeutic efficacy and increased lifespan of the affected mice	(87)
In vitro	MVs	Lactobacillus acidophilus	Gradient ultra-centrifugation	Bacteriocins	Opportunistic pathogen: Lactobacillus acidophilus	• Natural bacteriocins within the composition of the MVs	• Effective adherence to the target pathogen and compromising of its growth and membrane integrity	(91)

EV, Extracellular vesicle; NS, Not specified; BBB, Blood-brain barrier; LFA-1, Lymphocyte function-associated antigen 1, ICAM-1, Intercellular Adhesion Molecule 1; LPS, Lipopolysaccharide; EAE, Experimental autoimmune encephalomyelitis; RBCs, Red blood cells; TPP1, tripeptidyl peptidase-1; Ref., References