Three known triterpenoids were isolated from MeOH extract of C. apiifolia (Ranunculaceae). Their structures were identified as oleanolic acid (1), ursolic acid (2), hederagenic acid (3) by comparison of their physicochemical and spectral data with the literature values. Among them, 2 was isolated for the first time from this plant. The isolated compounds were evaluated for their cytotoxicity against L1210, HL-60, SK-OV-3 tumor cell lines. All compounds 1-3 were shown good activities with IC50 values ranging from 7.7 to 25.6 μg/ml. This result suggests that triterpenoids 1-3 are main cytotoxic principles of this plant.

Phytochemical study on the EtOAc fraction from the MeOH extract of the leaves of Cedrela sinensis led to the isolation of five known phenolic compounds (1-5), whose structures were identified as (+)-catechin (1), kaempferol-3-0-α- L-rhamnopyranoside (2), quercetin (3), quercetin-3-O-α-L-rhamnopyranoside (4), and quercetin-3-O-β-D-glucopyranoside (5), respectively, by comparing their spectral (uv, JR, IH and 13C-NMR, and ESI-MS) and physicochemical data with those reported in the literature. Among the isolated compounds (1-5), compounds 1 and 3-5 exhibited significant DPPH radical scavenging effects with IC50 values ranging from 21.3±1.4 to 38.1±3.2 μM as well as superoxide anion radical scavenging effects with IC50 values ranging from 9.4±0.7 to 21.2±3.6 μM. Furthermore, compounds 1 and 3-5 also exhibited considerable inhibitory effects on LDL peroxidation induced by either CU2+ or AAPH with IC50 values ranging from 1.4±0.4 to 11.9±1.4 μM. These results indicated that flavonoids are the major constituents of C. sinensis and considered to be antioxidant principles of this plant.

As a result of cytotoxic compounds against cancer cell lines from natural sources, senven compounds were isolated from the leaf and twig of Acer okamotoanum Nakai. The compounds (1-7) were identified as ethyl gallate (1), methyl gallate (2), gallic acid (3), trans resveratrol-3-O-β-D-glucopyranoside (4), acertannin (5), nikoenoside (6), and fraxin (7) by physicochemical and spectroscopic data (including mp, UV, IR, MS, 1H-NMR, 13C-NMR, DEPT, and HMBC) in comparison with those of published papers. All the compounds were tested for their cytotoxic activity against L1210, HL-60, K562, and B16F10 cancer cell lines in vitro by MTT assay method. Compounds 1-3 and 5 showed cytotoxic activity against all tested cell lines with IC50 values ranged from 12.5 to 72.2 μM. Of the compounds, methyl gallate (2) exhibited the most potent cytotoxic activity against L1210, HL-60, K562, and B16F10 tumor cells with IC50 values of 12.5, 48.3, 22.8, and 22.8 μM, respectively. Other compounds did not show any cytotoxic activity against four cancer cell lines.

The antioxidant effect of methanol extract (ME) and water extract (WE) from Clematis trichotoma was evaluated as primary study to scavenge stable 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH), inhibited iron-induce lipid peroxidation in linoleic acid emulsion, peroxidation of liposome induced by Fe3+/H2O2/ascorbie acid, and on Fe2+/H2O2 induced the mitochondrial lipid peroxidation. In secondary study, five flavonoids as luteolin (1), quercetin (2), apigenin (3), hirsutrin (4), kaempferol-3-O-glucoside were isolated (5). Among them, compounds 1 and 2 showed good activities in all the model systems. Compound 3 exhibited moderate antioxidant activities in both radical scavenging and these lipid peroxidation systems tested. Compound 4 showed significant inhibitions in liposome peroxidation and compound 5 displayed weak inhibition in all four tested systems. All the results presented herein indicate that products of C. trichotoma maybe useful in inhibiting membrane lipid peroxidation and preventing free radical-linked diseases.

Phytochemical study on the EtOAc fraction from a MeOH extract of the leaves of Alnus hirsuta Rupr. led to the isolation of nine compounds betulin (1), betulinic acid (2), hirsutanonol (3), hirsutenone (4), quercetin (5), avicularin (6), gallic acid (7), hyperin (8), and daucosterol (9). Among them, six compounds 1, 2, 57, and 9 are report from this plant for the first time. All isolated compounds were evaluated for their antioxidant activity using DPPH radical scavenging capacity and inhibition effect on mitochondrial lipid peroxidation. Six phenolic compounds 3-8 were found to have potent antioxidant activity. Of which, compounds 3, 4 and 5 showed significant free radical scavenging activity with the IC50 values of 18.3 ± 2.5, 15.7 ± 3.8 and 23.5 ± 3.1 μm, respectively. In addition, the compounds 3-8 exhibited inhibition effect on the mitochondrial lipid peroxidation with the IC50 values of 88.0 ± 6.5, 12.6 ± 1.2, 8.0 ± 1.1, 58.5 ± 4.3, 173.6 ± 15.2, and 75.0 ± 6.7 μm, respectively.

Five known anthraquinones, physcion (1), I-O-methylemodin (2), emodin (3), physcion-8-O-β,-D-glucopyranoside (5), emodin-8-O-β,-D-glucopyranoside (6) and two known stilbenes, trans-resveratrol (4), trans-resveratrol-3-O-β,-D-glucopyranoside (7) were isolated from MeOH extract of Reynoutria sachalinensis (Polygonaceae). All structures were unambiguously established by 1D and 2D NMR and MS data and the compounds were evaluated for their cytotoxicity against L1210, HL-60, BI6F10 tumor cell lines in MTT assay. Among the compounds, trans-resveratrol (4) exhibited significant cytotoxic activity with IC50 values of 9.2, 6.7 and 9.8 μg/ml, against the test cell lines respectively, but compounds 1-3 exhibited the moderate cytotoxic activity.