In vitro antioxidant and antidiabetic activity of essential oils encapsulated in gelatin-pectin particles against sugar, lipid and protein oxidation and amylase and glucosidase activity.

Abstract

The in vitro antioxidant and antidiabetic activities of Oliveria decumbens, Thymus kotschyanus, Trachyspermum ammi, and Zataria multiflora essential oils incorporated into gelatin‐pectin composite were investigated. The gas chromatography–mass spectrometry characterization revealed that thymol (1.2%–86.4%), carvacrol (3.2%–52.4%), gamma‐terpinene (0.0%–12.7%), para‐cymene (3.2%–5.2%), geraniol (0.0%–14.5%), and spathulenol (0.0%–13.6%) are the major constituents of the essential oils. Gelatin‐pectin composite incorporated with the essential oils exhibited acidic pH (2.40–3.04), low conductivity (265–278 µS/cm), low surface tension (19.0–23.5 mN/m), low Newtonian viscosity (23.7–28.5 mPa.s), negative zeta‐potential (14.2–16.9 mV), and nanoscale particle size (313–336 nm). These rheological properties result in the production of globular gelatin‐pectin nanoparticles with a size range of 500–700 nm. The FTIR spectra of gelatin‐pectin and gelatin‐pectin‐essential oils to some extent were similar, suggesting the noncovalent interactions between them. Gelatin‐pectin composite incorporated with the essential oils displayed antiglucose oxidation (130–150 µg/ml) antilipid peroxidation (120–130 µg/ml), antiprotein oxidation (150–168 µg/ml), and antiprotein glycation (145–170 µg/ml) as well as antiamylase (216–230 µg/ml), and antiglucosidase (212–238 µg/ml) activity. The essential oils strongly improved the antioxidant capacity of the gelatin‐pectin composite so strongly which can be recommended as a natural compound for oxidative stress management.