Zaini Assim

Antioxidant and antimicrobial properties of Litsea elliptica Blume and Litsea resinosa Blume (Lauraceae).

OBJECTIVE To investigate antioxidant and antimicrobial activities of two plant species, Litsea elliptica (L. elliptica) and Litsea resinosa (L. resinosa). METHODS In vitro method-2,2-diphenyl-1-picrylhydrazyl radical scavenging assay was conducted for antioxidant activity determination while antimicrobial assay consisted of agar well diffusion assay and mycelial radial growth assay. RESULTS Methanol extracts of root and stem of L. elliptica and L. resinosa exhibited the highest antioxidant activity with EC50 of 23.99, 41.69, 11.22 and 35.48 mg/L respectively. All methanol extracts of L. resinosa as well as root extracts from L. elliptica showed significant scavenging activity. Hexane extract from stem of L. resinosa presented the largest inhibition zone in Gram-negative bacteria Pseudomonas aeruginosa and Escherichia coli while chloroform extract from inner bark of L. resinosa showed major inhibition towards Gram-positive bacteria Bacillus subtilis. Essential oils from the root of both species showed significant antifungal activities which are 80.11% and 66.85% respectively. CONCLUSIONS Overall, methanol extracts from root and stem of both species showed antioxidant activity comparable to standard butylated hydroxytoluene. Extracts from L. resinosa demonstrated stronger antimicrobial properties compared to that from L. elliptica.

Di-n-but­yl{1-[1-(2-hydroxy­phen­yl)ethyl­idene]-5-[1-(2-oxidophen­yl)ethyl­idene]thio­carbazonato-κ3O5,N5,S}tin(IV)

The ‘symmetrical’ 1,5-bis[1-(2-hydroxyphenyl)ethylidene]thiocarbazone Schiff base condenses with dibutyltin oxide to form the title complex, [Sn(C4H9)2(C17H16N4O2S)], in which the deprotonated ligand O,N,S-chelates to the Sn atom of two crystallographically independent molecules. The ligand bears a formal negative charge on the S and one O atom; the other O atom retains its H atom. The Sn atoms are five-coordinated in a cis-C2NOSSn trigonal-bipyramidal environment, and the apical sites are occupied by the O and S atoms. In both molecules, the hydroxy group is hydrogen bonded to a double-bonded N atom, generating a six-membered ring. The amino group is a donor to the coordinated O atom of an adjacent molecule, the hydrogen-bonding interaction giving rise to a helical chain running along the b axis. In one of the independent molecules, the atoms of one of the n-butyl groups are disordered over two sets of sites with equal occupancy. In the other independent molecule, the atoms of both n-butyl groups are disordered over two sets of sites with equal occupancy and, in addition, the Sn and S atoms were also refined as disordered over two sets of sites with equal occupancy.

Extractives from Eusideroxylon Zwageri and Potoxylon Melagangai Against white-Rot Fungi

Pusat Asasi, Universiti Teknologi MARA, 42300 Bandar Puncak Alam, Malaysia; Department of Plant Science and Environmental Ecology, Faculty of Resource Science and Technology, Universiti Malaysia Sarawak, 94300 Kota Samarahan, Malaysia; Department of Chemistry, Faculty of Resource Science and Technology, Universiti Malaysia Sarawak, 94300 Kota Samarahan, Malaysia; E-mail: faiezah2892@puncakalam.uitm.edu.my