Stereospermum suaveolens (Roxb.) DC. Shows Potential in vivo and in vitro Bioactivities

Abstract

The methanol extract of Stereospermum suaveolens (Roxb.) DC was investigated for antidiabetic, antidiarrheal
and analgesic activities in Swiss Albino mice. Antidiabetic activity was evaluated by oral glucose tolerance
test where the crude extract of S. suaveolens (400 mg/kg b.w.) exhibited 56.10% reduction of blood glucose level as
compared to 58.53% by standard glibenclamide (0.1 mg/kg b.w.). In the castor oil-induced diarrhea in mice, the plant
extract, at the dose of 400 mg/kg b.w. demonstrated 42.11% reduction of diarrheal feces, while the standard
loperamide revealed 57.89% reduction of diarrheal feces. The analgesic activity of S. suaveolens was assessed by
both radiant heat tail-flick and acetic acid-induced writhing test. The methanolic extract and different Kupchan
fractions of S. suaveolens were also subjected to screening for total phenolic content, DPPH free radical scavenging
assay, membrane stabilizing, thrombolytic and antimicrobial activities. In the DPPH assay, the aqueous soluble
fraction of methanolic extract revealed highest antioxidant properties with IC50 value of 18.99 μg/ml. The membrane
stabilizing activity was assessed by hypotonic solution- and heat-induced methods and was compared with standard
acetyl salicylic acid. In hypotonic solution-induced haemolysis, the hexane and carbon tetrachloride soluble fraction
inhibited 54.42% and 52.67% haemolysis of RBCs, respectively. On the other hand, in heat-induced haemolysis, the
chloroform soluble fraction inhibited the haemolysis of RBC by 57.10% as compared to 72.09% produced by acetyl
salicylic acid. In antimicrobial assay by disc diffusion method, only the hexane and carbon tetrachloride soluble
fractions demonstrated moderate antimicrobial activity (zone of inhibition = 7.0-15.0 mm) against the test organisms.