Antioxidant Chemical Constituents from Lychee Seed (Litchi chinensis Sonn.)

Aims: To research non-flavonoids chemical constituents from the lychee seed.

Study Design: Chemical constituents were isolated and elucidated from the lychee seed and their antioxidant activities were also estimated.

Place and Duration of Study: School of Pharmacy, Guangdong Pharmaceutical University, between September 2015 and March 2018.

Methodology: All compounds were isolated by Silica gel, Sephadex LH-20, ODS as well as HPLC chromatography and confirmed by 1D and 2D NMR. The DPPH radical scavenging capacities of these isolated compounds were measured using the DPPH assay.

Results: Seventeen compounds were isolated and identified from the lychee seed (1–17). Among them, amentoflavone (1), (7R,8S)-dihydrodehydrodiconiferyl alcohol 9′-O-β-D-glucopyranoside (3), arjunglucoside I (5), 3β-hydroxy-7α-methoxy-24β-ethyl-cholest-5-ene (7), 4-hydroxy-5-(9′-oxo-8′-pyrrolidinyl)-benzoic acid (8), 1-pyrrolidineacetic methyl ester (9), phenylalanine methyl ester (10), 2-hydroxyquinoline-4-carboxyic acid (11), 3,4-dihydroxy-cyclohexanecarboxylic acid-methyl ester (13), 1,1-cyclopropanediacetic acid,1-methyl ester (15), cyclopropaneacetic acid, 2-(methoxycarbonyl) (16) were first isolated from lychee seed and 3 and 17 exhibited antioxidant capacities on DPPH radical scavenging.

Conclusion: This study suggests that compounds from the seed of Litchi chinensis Sonn. showed potential antioxidant properties, which mean that lychee seed could be utilized as a natural antioxidant for health care.