A simple and convenient method for the preparation of antioxidant peptides from walnut (Juglans regia L.) protein hydrolysates.

BACKGROUND: Walnut (Juglans regia L.), that belongs to the Juglandaceae family, is one of the nuts commonly found in Chinese diets. Researchers had obtained peptides from walnut protein hydrolysates, and these peptides exhibited the high antioxidant activities. The objective of this study was to develop a simple and convenient method for a facile and reproducible preparation of antioxidant peptides from walnut protein hydrolysates. RESULTS: Walnut proteins were extracted from walnut kernels using continuous countercurrent extraction process, and were separately hydrolyzed with six types of proteases (neutrase, papain, bromelain, alcalase, pepsin, and pancreatin). Then, hydrolysates were purified by ultrafiltration. The yields and purity of the peptides prepared using neutrase and papain were 16 and 81 % at least, respectively, higher than others, and had low molecular weight, 99 % of which were less than 1500 Da. Furthermore, the bioassay indicated that the two peptides exhibited the high antioxidant activities in the DPPH (IC50 values: 59.40 and 31.02 µg/mL, respectively), ABTS (IC50 values: 80.36 and 62.22 µg/mL, respectively), and superoxide radical scavenging assay (IC50 values: 107.47 and 80.00 µg/mL, respectively). CONCLUSIONS: The method combines the advantages of generality, rapidity, simplicity, and is useful for the mass production of walnut peptides.Graphical AbstractPreparation of antioxidant peptides from walnut (Juglans regia L.) protein hydrolysates.

Antiproliferative and apoptosis inducing effect of essential oil extracted from Cyrtomium fortumei (J.) Smith leaves.

Cyrtomium fortumei (J.) Smith is an endemic species in China, which has been proved to be an important Chinese herbal medicine. However, chemical composition and bioactivity of essential oil (EO) of C. fortumei (J.) Smith leaves remain unclear. In present study, we isolated EO from the plant by supercritical carbon dioxide extraction assay (SFE-CO2), and investigated on cancer cells MGC-803, MCF-7, BGC-823, Bcap-37, A375, and A549 in vitro by MTT assay. 26 compounds were identified by GC-MS analysis, and the EO showed significant antitumor activities against MGC-803, Bcap-37, and A549 cancer cell lines (IC50 values ranging from 0.15 to 0.24 mg/mL), and the activities of its main component were also studied. Subsequent fluorescence staining and flow cytometry analysis indicated that the EO could induce apoptosis in MGC-803, Bcap-37, and A549 cell lines, and the apoptosis ratios reached 26.44 % after 48 h of treatment at 0.15 mg/mL in MGC-803 cells. Caspase 3 activity in MGC-803 cells was also determined when the cells treated with the oil, and the activity of caspase 3 enzyme was increased compared to the control. This study suggests that the EO isolated from C. fortumei (J.) Smith could inhibit the growth of human carcinoma cells, and it could induce apoptosis of cancer cells.

Chemical constituents of Cyrtomium fortumei (J.) Smith.

Five known compounds, 6'-methylglucuronide-5-hydroxy-chromone (1), ethyl α-d-glactopyranoside (2), neoechinulin A (3), 9,12,13-trihydroxyoctadeca-10(E),15(Z)-dienoic acid (4) and phellopterin (5), were isolated from water extract of Cyrtomium fortumei (J.) Smith. Compounds 1-5 were isolated from this genus for the first time, and all the compounds were evaluated in vitro against a panel of human cancer cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Among them, compounds 3 and 4 exhibited significant cytotoxic activities, with IC50 values of 15.2 and 18.3 µg/mL on MGC-803 cells, respectively.

Discovery and antitumor activities of constituents from Cyrtomium fortumei (J.) Smith rhizomes.

BACKGROUND: Cyrtomium fortumei (J.) Smith is an important Chinese herbal medicine because of its biological functions. However, systematic and comprehensive studies on the phytochemicals from Cyrtomium fortumei (J.) Smith and their bioactivity are limited. RESULTS: Using the bioassay-guided technique, the ethyl acetate and n-BuOH extracts of the rhizomes of Cyrtomium fortumei (J.) Smith were shown to exhibit good antitumor activities, consequently leading to the isolation of 23 compounds. All compounds were isolated from the plant for the first time. The inhibitory activities of these compounds were investigated on tumor cells MGC-803, PC3, and A375 in vitro by MTT (thiazolyl blue tetrazolium bromide) assay, and the results showed that pimpinellin (3) had potent cytotoxic activities against the three cell lines, with the IC50 values of 14.4 ± 0.3 µM, 20.4 ± 0.5 µM, and 29.2 ± 0.6 µM, respectively. The mechanism of the antitumor action indicated that pimpinellin inhibited the growth of MGC-803 cells via the induction of tumor cell apoptosis, with apoptosis ratio of 27.44% after 72 h of treatment at 20 µM. CONCLUSIONS: This study suggests that most of the compounds from the roots of Cyrtomium fortumei (J.) Smith could inhibit the growth of human carcinoma cells. Moreover, pimpinellin inhibited the growth of tumor cells via the induction of tumor cell apoptosis.

Chemical constituents of the ethyl acetate extract of Belamcanda chinensis (L.) DC roots and their antitumor activities.

An activity-directed fractionation and purification process was used to isolate antitumor compounds from the roots of Belamcanda chinensis (L.) DC. The ethyl acetate extract showed greater antitumor activities than the other extracts, consequently leading to the isolation of 18 compounds identified as ß-sitosterol (1), dausterol (2), quercetin (3), kampferol (4), shikimic acid (5), gallic acid (6), ursolic acid (7), betulin (8), betulonic acid (9), betulone (10), tectoridin (11), irisflorentin (12), 4',5,6-trihydroxy-7-methoxyisoflavone (13), tectorigenin (14), irilins A (15), iridin (16), irigenin (17), and iristectongenin A (18). Compounds 3-10, 13, and 15 were isolated from B. chinensis for the first time. Compounds 4 and 7-10 showed potent cytotoxic activities against PC3, MGC-803, Bcap-37, and MCF-7 cell lines. The mechanism of the antitumor action of compound 7 was preliminarily investigated through acridine orange/ethidium bromide (AO/EB) staining, Hoechst 33258 staining, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, which indicated the growth inhibition of MGC-803 cells via the induction of tumor cell apoptosis.