Mannose Nanoparticles from Guar Gum: Macrophage Vectorization, Drug Delivery and Leishmanicidal Efficacy against Wild and Drug Resistant Strains

Introduction: Guar gum (GG) is obtained in sufficient purity from Cyamopsis tetragonoloba seeds. Unlike cellulose, GG presents one β 1-4 mannose chain interposed with α 1-6 galactose substituents. GG hydrates hugely in... [ view full abstract ]

Introduction: Guar gum (GG) is obtained in sufficient purity from Cyamopsis tetragonoloba seeds. Unlike cellulose, GG presents one β 1-4 mannose chain interposed with α 1-6 galactose substituents. GG hydrates hugely in mannose surfaced coiled assembly formations. We are successful for the first time in extracting mannose nanoparticles (GMn) from GG. GMns observed rapid receptor gated uptake in macrophages. Drug loaded GMns were used against macrophage resident L. donovani strains.
Methods: Temperature controlled GG hydrolysis in sulfuric acid (64%) yielded GMns spheroids, TEM size 48.8 nm, ζ potential -20.4mv. Epichlorohydrin in liquor ammonia reactions on GMn provided cationic modifications and fluorescent rhodamin dye was linked following isothiocyanate chemistry. Quercetin (Qr) was loaded in GMns by porous diffusion in phosphate buffer. The loading efficiency in HPLC was 87% w/w and FT-IR studies confirmed nano-chemistry. Qr loaded GMns efficacy against L. donovini AG 83 strains were studied against axenic and macrophage infested amastigotes.

Results and Discussion: GMns and Qr loaded GMns were taken up rapidly in mouse peritoneal macrophages. Uptake was complete within 60 min and 2 mM mannose but not galactose could inhibit that significantly. Concanavallin A agglutination experiments confirmed GMns 42% surface mannose density. Qr loaded GMns were safe and powerful leishmanicidals against wild and drug resistant strains (Table 1).

Table 1. Antileishmanial efficacy of quercetin loaded GMns against Leishmania donovani.