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 b-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.

The current study targets the chemical constituents of Caesalpinia decapetala (Roth) Alston and investigates the bioactivities of the isolated compounds. Fourteen known compounds were isolated using column chromatography, and structural identification was performed by physical and spectral analyses. The biological activities of the compounds were also evaluated by 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and 2,2-diphenlyl-1-picrylhydrazyl (DPPH) assays. Emodin (6), baicalein (9), and apigenin (12) displayed antitumor activities against the MGC-803 cell line, while quercetin (2), rutin (5), baicalein (9), and epicatechin (13) showed stronger DPPH scavenging activities compared with ascorbic acid. Andrographolide (1), quercetin (2), bergenin (4), rutin (5), emodin (6), betulin (7), baicalein (9), polydatin (10), salicin (11), and apigenin (12), were obtained from C. decapetala (Roth) Alston for the first time.

Cold stress caused by a low temperature is a significant threat to tea production. The application of chitosan oligosaccharide (COS) can alleviate the effect of low temperature stress on tea plants. However, how COS affects the cold stress signaling in tea plants is still unclear. In this study, we investigated the level of physiological indicators in tea leaves treated with COS, and then the molecular response to the cold stress of tea leaves treated with COS was analyzed by transcriptomics with RNA-Sequencing (RNA-Seq). The results show that the activity of superoxide dismutase (SOD) activity, peroxidase (POD) activity, content of chlorophyll and soluble sugar in tea leaves in COS-treated tea plant were significantly increased and that photosynthesis and carbon metabolism were enriched. Besides, our results suggest that COS may impact to the cold stress signaling via enhancing the photosynthesis and carbon process. Our research provides valuable information for the mechanisms of COS application in tea plants under cold stress.

Bacterial canker disease caused by Pseudomonas syringae pv. actinidiae (Psa) is a devastating disease of kiwifruit, which is severely limiting the development of the kiwifruit industry. Ethylicin is a broad-spectrum plant biomimetic fungicide. However, its application in the control of kiwifruit bacterial canker is rarely reported, and the mechanism of ethylicin on Psa remains unknown. In this study, we investigated the effect of ethylicin on Psa in vitro and in vivo and found that ethylicin can inhibit the growth of Psa and prevent the cankering in the plant stem. Mechanism investigation indicated that ethylicin acted by limiting the movement of Psa, destroying the cell membrane of Psa, and inhibiting the formation of Psa biofilm. In addition, it was also found through transcriptomics research that ethylicin can up-regulate the expression of genes related to protein export and biofilm formation–Pseudomonas aeruginosa and down-regulate the expression of genes related to flagellar assembly in Psa. This study concluded that ethylicin can effectively inhibit Psa growth, and it could help to gain a better understanding of the mechanisms of ethylicin inhibiting Psa and provide practical data for the application of ethylicin as a highly potent agent for controlling the bacterial canker disease of kiwifruit.