Schiff's bases were obtained from aromatic/heterocyclic sulfonamides and amino-sulfonamide derivatives, such as sulfanilamide, homosulfanilamide, 4-aminoethyl-benzenesulfonamide and 5-amino-1,3,4-thiadiazole-2-sulfonamide. Metal complexes of some of these Schiff's bases, incorporating Zn(II), Co(lI), Ni(II) and Cu(II) ions, were also prepared and tested as inhibitors of the zinc enzyme carbonic anhydrase (CA), and more specifically the red blood cell isozymes I and II. The Schiff's bases behaved as medium potency CA I and CA II inhibitors, whereas their metal complexes showed a highly enhanced potency, with several low nanomolar CA II inhibitors detected.

Metal complexes of aromatic/heterocyclic sulfonamides act as stronger inhibitors of the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1) as compared to the uncomplexed sulfonamides from which they are derived. Here we report the synthesis and inhibition studies against the physiologically relevant isozymes CA I, CA II and CA IV, of a series of metal complexes (Co(II), Ni(II) and Cu(II) derivatives) of a Schiff-base ligand, obtained from sulfanilamide and salicylaldehyde. The best activity was observed for the Cu(II) and Co(II) complexes, against CA II and CA IV, for which inhibition constants in the range of 15-39 and 72-108nM, respectively, were seen. The enhanced efficacy in inhibiting the enzyme may be due to a dual mechanism of action of the metal complexes, which interact with CA both by means of the sulfonamide moieties as well as the metal ions present in their molecule.

Delayed planting of sugarcane crop after harvesting of seed is a common farming practice in all cane growing areas of Pakistan. This study was conducted to find out comparative effect of sugarcane seed having different harvesting or stalling period on productivity of sugarcane. The experiment was planted in randomized complete block design with split plot arrangement for two consecutive years. Three commercial sugarcane varieties viz. CPF 248, CPF 247 and CPF 246 were kept in main plots whereas cane setts staling; fresh, 3 days, 6 days & 9 days old stale cane setts were placed in sub-plots. The data revealed that sugarcane clones were differed significantly for most of biometric traits under study except cane yield whereas impact of cane setts stalling was also significant excluding for sugar contents. While, interactive effect of all treatment combinations for sugarcane clones and cane setts stalling was found significant except for CCS%. It was found that clone CPF 247 exhibited highest cane and sugar yield by planting fresh cane setts as against lowest for CPF 248 when planted with 9 days old stale cane setts during both years of experimentation. Better growth and yield related traits were predominantly attributed to planting of fresh cane seed having better germination, tillering and cane density.