Simultaneous Occurrence of Nanospheres and Nanofibers Self‐Assembled from Achiral Tripeptides

Abstract The achiral tripeptide Boc‐Aib‐MABA‐Aib‐OMe has the ability to co‐exist as nanospheres and as a network of nanofibers in methanol. Furthermore, AFM and TEM images show the presence of bulges in the network of nanofibers. Interestingly, the formation of nanofibers is seen to emerge from the outer boundary of the spherical structures. Some of the nanofibers curl up at the tip and later result in the formation of hollow nanospheres with thick boundaries. The presence of β‐turn‐like structures with hydrogen bonding is observed using FT‐IR studies. The presence of hydrogen bonding is also demonstrated by using NMR studies

Two novel polychiral furanopyrans from <em>Orthosiphon diffusus</em> (Benth.)

855-861Chemical investigation on Orthosiphon diffusus has resulted in the isolation of two new polychiral furanopyrans, orthodiffenes AM-1 and AM-2 which have been thoroughly characterized by detailed spectroscopic studies including IR, NMR (1D and 2D) and FABMS spectra. The in vitro cytotoxic activity of these two compounds has been tested against U-937 and HeLa cells using camptothecin and etoposide as the positive controls. Both the metabolites show modest activity against HeLa cells with IC50 values of 26.98 &micro;g/mL and 21.18 &micro;g/mL, respectively