GC-MS analysis of D-pinitol in carob: Syrup and fruit (flesh and seed)

J Chromatogr B Analyt Technol Biomed Life Sci. 2019 May 15:1116:60-64. doi: 10.1016/j.jchromb.2019.04.008. Epub 2019 Apr 3.

Abstract

D-pinitol (3-O-methyl-D-chiro-inositol) is a well-known bioactive compound with anti-diabetic and anti-oxidant biological functions. A gas chromatography-mass spectrometry (GC-MS) method was developed for its quantitation in carob syrup, flesh and seed samples originated from Cyprus. The analysis was performed after derivatization of carbohydrates and polyols into trimethylsilyl ether derivatives. D-pinitol was determined in 13 carob syrup samples, in concentrations ranging 65.71 ± 4.60 - 77.72 ± 5.44 mg/g (mean: 68.58 ± 4.80 mg/g, n = 13). In two commercial samples, it was determined in relative medium-low concentrations (21.96 ± 1.54 and 44.71 ± 3.13 mg/g), revealing possible adulteration; however, this needs further investigation. Similarly, it was determined in high concentrations in carob flesh samples, in concentrations ranging 53.20 ± 3.72 - 54.58 ± 3.82 mg/g (mean: 53.81 ± 3.76 mg/g, n = 3). On the other hand, seed samples proved very poor in D-pinitol (<LOD). Therefore, bioprospecting of carob fruit and syrup is highlighted. Compared to other plants or legumes, carob appears to be the richest source of D-pinitol, highlighting carobs role as a functional organic food. The historical and cultural association of Cyprus with carobs is linked with traditional foods and habits.

Keywords: 3-O-methyl-D-chiro-inositol; Ceratonia siliqua L.; Cyclitols; Derivatization; Polyols; Sugar alcohols.

MeSH terms

  • Fabaceae / chemistry*
  • Fruit / chemistry
  • Galactans / chemistry*
  • Gas Chromatography-Mass Spectrometry / methods*
  • Inositol / analogs & derivatives*
  • Inositol / analysis
  • Limit of Detection
  • Linear Models
  • Mannans / chemistry*
  • Plant Extracts / chemistry*
  • Plant Gums / chemistry*
  • Reproducibility of Results
  • Seeds / chemistry

Substances

  • Galactans
  • Mannans
  • Plant Extracts
  • Plant Gums
  • pinitol
  • Inositol
  • locust bean gum