Leaves from the Okinawa-grown tsubaki, or camellia japonica (a relative of camellia sinensis or tea), have a high level of an ellagic acid called Okicamelliaside (GOOGLE SEARCH).
STUDY: Okicamelliaside, an extraordinarily potent anti-degranulation glucoside isolated from leaves of Camellia japonica (http://www.ncbi.nlm.nih.gov/pubmed/21150097, Download full article here) ABSTRACT: Guided by anti-degranulation assays, we isolated from leaves of Camellia japonica an ellagic acid glucoside named okicamelliaside. The structure was elucidated as 3,4-dioxoloellagic acid 4'-O-β-D-glucopyranoside by spectroscopic and chemical methods. Okicamelliaside was 12,000 times more potent than the antihistaminic drug, ketotifen fumarate, in inhibiting the degranulation of RBL-2H3 cells. Three other studies cataloged on Pubmed.gov