Intestinal absorption of luteolin from peanut hull extract is more efficient than that from individual pure luteolin.

Luteoin is one of the main flavones and the crucial effective component of peanut hull extract (PHE). The present paper aims to elucidate the absorption mechanism of luteolin and clarify whether its absorption occurs primarily at a specific site of the intestine by an in situ single-pass intestinal perfusion (SPIP) model. Moreover, the paper investigates the difference in absorption of luteolin when it is administered in PHE form and as pure luteolin by the SPIP model and in vivo pharmacokinetics studies. Results showed that the effective permeability ( P eff) and absorption rate constant ( k a) of pure luteolin(5.0 microg/mL) in duodenum and jejunum were not significantly different, but markedly higher than that in the colon and ileum. The P eff and k a of luteolin in jejunum were concentration-independent, and the ATP inhibitor (DNP) did not influence P eff and k a of pure luteolin. However, the P eff and k a of luteolin in PHE were significantly greater than that of pure luteolin. The pharmacokinetics study showed that following oral administration of a single dose of pure luteolin (14.3 mg/kg) or PHE (= 14.3 mg/kg of luteolin) in rats, the peak concentration of luteolin in plasma ( C max) and the area under the concentration curve (AUC) for pure luteolin were 1.97 +/- 0.15 microg/mL and 10.7 +/- 2.2 microg/mL.h, respectively. These parameters were significantly lower than those of the PHE group ( P < 0.05), C max = 8.34 +/- 0.98 microg/mL and AUC = 20.3 +/- 1.3 microg/mL.h, respectively. It can be concluded that luteolin is absorbed passively in the intestine of rats and that its absorption is more efficient in the jejunum and duodenum than in the colon and ileum. The bioavailability of luteolin in PHE form is significantly greater than that of pure luteolin.

[Determination of bis (p-fluorobenzyl) trisulfide and bis (p-fluoro-benzyl) disulfide in lungs of rat by HPLC].

OBJECTIVE: To establish an HPLC method for analysis of bis(p-fluorobenzyl) trisulfide(BFTS) and bis(p-fluorobenzyl)disulfide(BFDS) in the lungs of rat. METHODS: 5.0 ml extract solvent (n-hexane: isopropyl alcohol=95:5, v/v) and 20 microl of 11.50 microg/ml dibenzyl disulfide (internal standard) were added to 0.2 g lung sample followed by homogenization. After centrifugation, 4.0 ml of supernatant was separated and vaporized to dryness, and the residue was reconstituted in mobile phase for HPLC analysis. The HPLC analysis was performed on an SB C18 column using acetonitrile and water (65:35, v/v) as mobile phase with a flow rate of 1.0 ml/min with UV detection at 220 nm. RESULT: The calibration curves for BFTS and BFDS in sample were linear over the concentration ranges of 0.04712-14.78 microg/g(r=0.999) and 0.04831-23.96 microg/g(r=0.999), respectively. The limits of quantification were 0.04712 microg/g and 0.04831 microg/g for BFTS and BFDS, respectively. The assay recoveries for BFTS and BFDS ranged from 95.71%-107.2% and 90.00%-110.5%, respectively. The precisions were obtained with RSD of <10%. The developed method was successfully applied to study the content of BFTS and BFDS in the lungs of rats after intravenous injection of 12.5 mg/kg BFTS. CONCLUSION: The method developed is simple, selective, repeatable and accurate, which can be applied to study the tissue distribution of BFTS and BFDS.