The seeds of Litchi chinensis Sonn. (Sapindaceae) have been used as a traditional Chinese medicine recorded in the Pharmacopoeia of the People’s Republic of China. Litchi seeds possess pharmacological effects of blood glucose reduction, blood lipid regulation, antitumor, and so on, while their bioactive constituents are still poorly understood.

Under the supervision of Prof. XIE Haihui and WEI Xiaoyi, PhD student XU Xinya in South China Botanical Garden, CAS investigated the chemical constituents of litchi seeds and obtained 31 compounds, including seven proanthocyanidins, four sesquiterpenes, nine flavonoids, and three galactosylacylglycerols. Among them, six are new and 20 known ones have been isolated from this species for the first time.

The isolated principal compounds were evaluated for biological activities. Two sesquiterpenoid glucosides and three flavonoid glycosides showed potent in vitro cytotoxicity against human carcinoma cell lines of A549, LAC, HeLa, and Hep-G2. Seven proanthocyanidins exhibited in vitro antiviral activity against coxsackie virus B3 (CVB3) and herpes simplex virus 1 (HSV-1), cAMP phosphodiesterase inhibitory and antioxidant activities.

These results have been published successively in Food Chemistry (2010, 123, 1123–1126), Journal of Agricultural and Food Chemistry (2010, 58, 11667–11672; 2011, 59, 1205–1209) and Fitoterapia (2011, 82, 485–488).

New compounds isolated from litchi seeds.