PostersPlanta Med. 56(1990) 649 structure was established by UV, EI-MS, 1H-NMR, and '3C-NMR studies. In addition, the flavonoid galangin 3-methyl ether was detected. 5,7-Dihydroxy-3 ,8-dimethoxyflavone showed antibacterial activity against Gram-positive bacteria (Staphylococcus epidermidis and Bacillus sp.) at an MIC of 50 ig/ml and against Gram-negative bacteria (Escherichia coli K 12 and Ser-

Diurnal fluctuations were observed in nitrate reducta.se activity in Lemna paucicostatu Hegelm, grown under 16‐h photoperiod. The enzyme activity showed a single peak in the middle of the photo period, i.e. 8 h after the onset of light. The activity decreased during the latter half of the photoperiod and reached a minimum level in the middle of the dark period. The peak in enzyme activity persists in continuous light as well as continuous dark, at least for a couple of days, suggesting the existence of endogenous rhythmicity

The Bryophyllum pinnatum refers to the family Crassulaceae. The glycoprotein from the 0.9% of normal saline extracts of Bryophyllum pinnatum leaves was refined by dialysis with 50% of ammonium sulfate. Protein concentration was invented by Lowry’s method. The dialyzed sample allowed for SDS-PAGE to determine the molecular weight (Mr ). The antioxidant activity of crude lectin extract has been assessed by the DPPH (1, 1-Diphenyl-2-picrylhydrazyl) and ABTS methods. The present study aims to verify the antioxidant activity of lectins detached from the leaves of Bryophyllum pinnatum.