Chemical constituents from Chonemorpha fragrans roots and antibacterial activity studies of sarcorucinine D.

Nine non-alkaloid constituents viz., sitostenone (1), ß-sitosterol (2), naringenin (3), aromadendrin (4), matairesinol (5), vanillic acid (6), ferulic acid (7), protocatechuic acid (8) and sitosterol-3-O-ß-D-glucopyranoside (9) were isolated from the acetone extract as well as five alkaloids viz., japindine (10), sarcorucinine D (11), dictyophlebin (12), chonemorphine (13) and N-formylchonemorphine (14) were isolated from the ethanol extract of Chonemorpha fragrans roots. Except ß-sitosterol, all other non-alkaloid compounds and the alkaloid sarcorucinine D are being reported for the first time from C. fragrans. From the MIC and MBC values, it has been found that sarcorucinine D shows most promising antibacterial activity. Quantification of antibacterial activity as well as killing curve determinations were performed in order to confirm the efficacy of the compound. The cytotoxic activity studies revealed that it is nontoxic up to 100 µM concentration.

Zn2+ Interrupts R4-R3 Association Leading to Accelerated Aggregation of Tau Protein.

Direct binding of divalent metal ion, especially Zn2+ , have been shown to increase the rate of tau aggregation and enhance tau toxicity in cells. Hence, understanding the molecular basis of the Zn2+ -accelerated tau aggregation can potentially determine the molecular interactions modulating tau aggregation. Herein, we show that Zn2+ coordinates through the cysteine in R3 repeat and significantly accelerates the aggregation rate of the three repeat tau constructs (K19) but that the coordination is incapable of increasing the aggregation rate of the 20 amino acid peptide derived from the R3 repeat (R3) of tau. The NMR characterization of the binding of Zn2+ to K19, together with the aggregation studies with K19, R3 and R4 peptides, reveal the presence of an aggregation-inhibitory interaction between the R3 and R4 repeat of K19. Our data show that binding of Zn2+ to R3 repeat of tau, weaken the aggregation-inhibiting influence between R3 and R4 repeats, leading to faster aggregation of tau protein.

Anti-metastatic effect of deoxyelephantopin from Elephantopus scaber in A549 lung cancer cells in vitro.

In this study, we focused on the in vitro anti-metastatic effects of deoxyelephantopin (DOE), a sesquiterpene lactone from Elephantopus scaber on lung cancer A549 cells. DOE significantly decreased the metastatic potential of A549 cells as demonstrated by transwell invasion and migration assay. DOE inhibited the expression of matrix metalloproteinase-2 (MMP-2), MMP-9, urokinase-type plasminogen activator and urokinase-type plasminogen activator receptor at transcript level. Tissue inhibitors of metalloproteinase-2 (TIMP-2) mRNA levels was up-regulated in A549 tumour cells without any change in TIMP-1 expression after DOE treatment. DOE inhibited the protein levels of p-ERK1/2 and p-Akt in A549 cells but it activated p-JNK, p-p38 protein expression. NF-κB and IκBα expressions were down-regulated in DOE-treated cells. All these results demonstrated that DOE has shown anti-metastatic activity against A549 tumour cells.