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The leaves of Pereskia grandifolia Haw. (Cactaceae), commonly known as “Jarum Tujuh Bilah” in Malaysia, have been traditionally used as natural remedy in folk medicine by the locals. In the present study, the antioxidant potential of P. grandifolia crude methanol and its fractionated extracts (hexane, ethyl acetate and water) have been investigated, employing three different established testing systems, such as scavenging activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, reducing power assay and β-carotene method. The total phenolic content of the P. grandifolia extracts was also assessed by the Folin-Ciocalteau’s method. The ethyl acetate extract showed significantly the highest total phenolic content, DPPH scavenging ability and antioxidant activity in β-carotene bleaching assay while the hexane extract possessed significantly strongest reducing power. The data obtained in these testing systems clearly establish the antioxidant potency of P. grandifolia. As such, this is the first report on the antioxidant activities of P. grandifolia.

A series of diorganotin complexes with Schiff base ligands, (E)-N′-(5-bromo-2-hydroxybenzylidene)-3-hydroxy-2-naphthohydrazide, H 2 L1, and (E)-N′-(5-chloro-2-hydroxybenzylidene)-3-hydroxy-2-naphthohydrazide, H 2 L2, were synthesized and characterized by elemental analysis, IR, 1 H, 13 C and 119 Sn NMR spectroscopy. The molecular structures of the complexes, [(5-bromo-2-oxidobenzylidene)-3-hydroxy-2naphthohydrazidato]di(o-chlorobenzyl)tin(IV) 6 and [(5-chloro-2-oxidobenzylidene)-3-hydroxy-2-naphthohydrazidato]dibutyltin(IV) 9, were determined through single-crystal X-ray diffraction and revealed a distorted trigonal-bipyramidal configuration. The in vitro cytotoxic activity of the Schiff bases and their diorganotin complexes was also evaluated against several human carcinoma cell lines, namely HT29 (human colon carcinoma cell line), SKOV-3 (human ovarian cancer cell line), MCF7 (hormone-dependent breast carcinoma cell line) and MRC5 (non-cancer human fibroblast cell line). [(5-Bromo-2-oxidobenzylidene)-3-hydroxy-2-naphthohydrazidato]dibutyltin(IV) 2 and [(5-bromo-2-oxidobenzylidene)-3-hydroxy-2-naphthohydrazidato]dibenzyltin(IV) 5 were the most active diorganotin complexes of H 2 L1 ligand. Among the diorganotin complexes of H 2 L2 ligand, [(5-chloro-2-oxidobenzylidene)-3-hydroxy-2-naphthohydrazidato] dicyclohexyltin(IV) 11 showed good cytotoxic activity against all the tested cell lines. As such, the above compounds can be considered agents with potential anticancer activities, and can therefore be investigated further in in vitro or in vivo anticancer studies.