Hibiscus sabdariffa increases hydroxocobalamin oral bioavailability and clinical efficacy in vitamin B sub(12) deficiency with neurological symptoms

The aim of the study was to evaluate the bioavailability and clinical benefits of oral new formulation (HB sub(12)) of hydroxocobalamin (Hdrx) with Hibiscus sabdariffa (HS). First, in an observational study, a cohort of 30 vitamin B sub(12)-deficient patients (vit B sub(12) < 200 pg/mL) with neurological symptoms received oral fixed dose of Hdrx containing 15 mg Hdrx daily for 10 days followed by 15 mg monthly. Clinical benefits were evaluated on haematological and biochemical parameters, and neurological improvement at days 10 and 90 compared to day 0. To understand the mechanism, intestinal mucosa from mice were mounted in vitro in Ussing chambers to measure Hdrx Fluxes. In the clinical study, serum vitamin B sub(12) level increased from 55.1 plus or minus 36.9 to 1330 plus or minus 335.5 pg/mL at day 10 and 431.0 plus or minus 24.27 pg/mL at day 90, without overt adverse effects. In mice ileum, (i) intestinal bioavailability of Hdrx increased in dose-dependent manner with HB sub(12). The apparent permeability of Hdrx was P sub(app) = 34.9 plus or minus 4.6 10 super(-6) cm/s in the presence of 3 mg/mL (HB sub(12)B) compared to the control P sub(app) = 6.2 plus or minus 0.7 10 super(-6) cm/s. (ii) Total transepithelial electrical conductance (G sub(t)) increased in dose-dependent manner with HB sub(12), G sub(t) = 161.5 plus or minus 10.8 mS/cm super(2) with HB sub(12)B (Hdrx 1 mg + HS 3 mg) compared to the control Hdrx, G sub(t) = 28.7 plus or minus 4.0 mS/cm super(2). In conclusion, the clinical study suggests that injections are not required when Hdrx is given orally. Intestinal bioavailability of Hdrx increased in vitro when it was used concomitantly with HS.