Speciation analysis and the assessment of bioavailabilty of manganese in phytomedicines by extraction with octanol and determination by flame atomic absorption spectrometry

• Published in: Phytochemical analysis Vol. 16; no. 6; pp. 405 - 410
• Main Authors: Li, S.X, Zheng, F.Y, Liu, X.L, Cai, W.L
• Format: Journal Article
• Language: English
• Published: 2005
• Subjects: acidity; Atractylodes; bioavailability; chemical analysis; Flos carthami; Flos chrysanthemi; Fructus mori; gastric juice; herbaceous plants; Lycaenidae; manganese; plant biochemistry; Radix pseudostellariae; Semen persicae; speciation; Vespertilio superans
• ISSN: 0958-0344; 1099-1565

Trace elements in phytomedicines are present in the form of metallic complexes. Since n-octanol, a long-chain alkanol, presents a configuration similar to that of carbohydrates and lipids, the lipophilicity and absorptivity of organic medicines may be assessed from their distribution coefficients between octanol and water. This strategy has been used in order to define the species of manganese in a number of phytomedicines and to study the distribution of manganese in decoctions of phytomedicines in the stomach and the intestine. The concentrations of manganese in the original herbal materials and in octanol- and water-soluble fractions were determined by flame atomic absorption spectrometry following mixed acid digestion. The acidities of gastric and intestinal juices, the phytomedical composition and the compatibility of phytomedicines, i.e. the combination of single phytomedicines, greatly affected the manganese complexing ligands and determined the species and bioavailability of manganese. It is concluded that a knowledge of the level of octanol-soluble manganese in a phytomedicine could form the basis of dosage design in order to avoid manganese overload.