Bioavailability of citrus limonoids in humans

Area of Science:

• Pharmacokinetics and Metabolism
• Nutritional Science
• Analytical Chemistry

Background:

• Citrus limonoids, like limonin, are plant compounds with potential health benefits.
• Understanding their absorption, metabolism, and bioavailability in humans is crucial for evaluating their efficacy.
• Limonin glucoside is a water-soluble form that may enhance limonin absorption.

Purpose of the Study:

• To determine the absorption, metabolism, and bioavailability of limonin in humans after administration of limonin glucoside.
• To quantify limonin levels in plasma following varying doses of limonin glucoside.
• To assess the safety of high-dose limonin glucoside consumption.

Main Methods:

• Liquid chromatography/mass spectrometry (LC-MS) was used for plasma analysis.
• Four groups of healthy male and female subjects received doses ranging from 0.25 to 2.0 g of limonin glucoside.
• Plasma concentrations of limonin and related compounds were measured over time.

Main Results:

• Increasing doses of limonin glucoside led to higher plasma limonin concentrations (1.74–5.27 nmol/L).
• Mean time to maximum concentration (Tmax) for limonin was observed at 6 hours.
• A second compound, potentially a limonin epimer, was also detected in significant amounts.
• High variability in limonin concentration was noted among subjects.
• No adverse health effects were reported by participants.

Conclusions:

• Limonin glucoside is absorbed and metabolized to limonin in humans, demonstrating its bioavailability.
• The study provides valuable pharmacokinetic data for limonin and its derivatives.
• High doses of limonin glucoside appear to be safe for consumption in healthy adults.