Chiral hydroxymethyl-1H,3H-pyrrolo[1,2-c]thiazoles: the search for selective p53-activating agents for colorectal cancer therapy.

MANIO is an efficient p53-activating anticancer agent with remarkable selectivity to the p53 pathway and promising antitumor activity against colorectal cancer (CRC). Herein, a library of novel MANIO derivatives, including hydroxymethyl- and bis(hydroxymethyl)-1H,3H-pyrrolo[1,2-c]thiazoles, was synthesized by rational structural modulation. The antiproliferative activity of twenty derivatives was evaluated in a panel of human CRC cells with different p53 status. From this library, five compounds with R- and S-configuration and with aromatic or heteroaromatic groups at position 3, including the enantiomer of MANIO, were identified as selective towards p53-expressing cancer cells. On the other hand, two compounds with S-configuration, 6-hydroxymethyl- and 7-hydroxymethyl-5-methyl-3-phenyl-1H,3H-pyrrolo[1,2-c]thiazoles, showed high cytotoxicity against WTp53-expressing HCT116 colon cells but, unlike MANIO, exhibited p53-independent inhibitory activity in CRC. The results described provide relevant structural and pharmacophoric data for the design of new p53-activating agents for precision therapy of CRC or other p53-related cancers harboring both wild-type or mutated p53 forms.

Isolation and HPLC quantitation of kaurane-type diterpenes and cinnamic acid derivatives of long-term stored leaves of Mikania laevigata and Mikania glomerata.

The leaves of Mikania laevigata and Mikania glomerata are used in Brazil to treat respiratory affections, being kaurane-type diterpenes and coumarin considered as the bioactive compounds. The present study reports an investigation on the HPLC-DAD profiles and contents of coumarin (1), trans-o-coumaric (2), kaurenoic (3), benzoylgrandifloric (4) and cinnamoylgrandifloric (5) acids in dried leaves of Mikania species stored in dark room under controlled conditions. Excepting 2, the constituents were isolated and purified to be employed as reference compounds. The samples were analyzed at three monthly intervals up to 18 months for M. laevigata and 12 months for M. glomerata. trans-o-Coumaric was not detected in both, whereas 1 occurred only in M. laevigata. The concentrations of the assayed constituents did not vary significantly within the evaluated period (p < 0.05), for both species. In contrast, changes in the chromatographic profiles and spectral purity of peaks from 3, 4 and 5 were detected in samples of both Mikania stored for three months, while the coumarin profile in M. laevigata modified after six months of storage. The evaluation of chromatographic profiles based on spectral purity analyses of selected peaks was shown to be a more robust tool to access chemical stability of Mikania samples than the quantitation of chemical markers' contents.