Objective To isolate and identify the bioactive phytochemicals from the leaves of Camellia nitidissima. Methods The chemical constituents were isolated and purified by repeated silica gel, Sephadex LH-20, MCI gel columns, recrystallization, and semi-preparative HPLC techniques. The chemicl structures of these compounds were identified on the basis of spectral data including NMR and MS. Then quorum sensing inhibition(QSI) activities of these compounds were tested using Chromobacterium violaceum CV026 as the bioindicator strain. The antitumor activities of these compounds were measured using SGC7901 as cell proliferation and cytotoxicity. Resultsα-Spinasteryl-β-D-glucopyranoside(1), stigmasta-7,22-diene-3-O-[α-L-arabinopyranosyl(1→2)]-β-D-galactopyranoside(2), kaempferol 3-O-[2-O-(trans-p-coumaroyl)-3-O-α-D-glucopyranosyl]-α-D-glucopyranoside(3), aromadendrin(4), catechin(5), phlorizin 4′-O-β-D-glucopyranoside(6),(3R,6R,7E)-3-hydroxy-4,7-megastigmadien-9-one(7), dodecanoic acid(8), 3β-acetoxy-20-lupanol(9), and 3β,6α,13β-trihydroxyolean- 7-one(10) were successively isolated from the leaves of C. nitidissima. Unfortunately, these compounds had no QSI activity. Based on Cell Counting Kit-8(CCK-8) assay, compound 10 showed the best anti-tumor activity of all compounds(IC50 = 91.7 μg/m L). Conclusion Apart from compounds 4 and 5, other eight compounds are reported in this plant for the first time. All compounds show no QSI activity, compound 10 shows potential cytotoxic activity on SGC7901 cells in vitro. Objective To isolate and identify the bioactive phytochemicals from the leaves of Camellia nitidissima. Methods The chemical constituents were isolated and purified by repeated silica gel, Sephadex LH-20, MCI gel columns, recrystallization, and semi-preparative HPLC techniques. The chemicl structures of These compounds were identified on the basis of spectral data including NMR and MS. Then quorum sensing inhibition (QSI) activities of these compounds were tested using Chromobacterium violaceum CV026 as the bioindicator strain. The antitumor activities of these compounds were measured using SGC7901 as cell proliferation and cytotoxicity. Results α-Spinasteryl-β-D-glucopyranoside (1), stigmasta-7,22-diene-3-O- [α-L-arabinopyranosyl (1 → 2) α-D-glucopyranoside (3), aromadendrin (4), catechin (5), phlorizin 4 ’-O-β-D-glucopyranoside (6), (3R, 6R, 7E) -3-hydroxy-4,7-megastigmadien-9- Unfortunately, these compounds had no QSI activity (9), 3β-acetoxy-20-lupanol (9), and 3β, 6α, 13β-trihydroxyolean- Based on Cell Counting Kit-8 (CCK-8) assay, compound 10 showed the best anti-tumor activity of all compounds (IC50 = 91.7 μg / mL). Conclusion Apart from compounds 4 and 5, the other eight compounds were reported in this plant for the first time. All compounds show no QSI activity, compound 10 shows potential cytotoxic activity on SGC7901 cells in vitro.