Background: In this ethnopharmacological study, methanolic extract of the aerial plant parts of Phragmites karka (Family: Poaceae) and its petroleum ether and carbon tetrachloride fractions were investigated for bioactivities in Swiss-albino mice, namely, analgesic, central nervous system (CNS) depressant, hypoglycemic, and antidiarrheal activity.
Methods: The cold methanolic extract of the aerial plant parts of Phragmites karka (MEPK) was first prepared, and it was then further fractionated as petroleum ether (PEFMEPK) and carbon tetrachloride (CTFMEPK) fractions. Analgesic activity was performed employing acidic acid-induced writhing test, central analgesic effect by radiant heat tail-flick method. CNS depressant activity was evaluated by phenobarbitone-induced sleeping time test. Hypoglycemic activity was tested by glucose tolerance test (GTT). Antidiarrheal activity was evaluated by castor oil-induced diarrhea method. For all in vivo tests, doses of 200 and 400 mg/kg body weight were used.
Results: In the mice model, the MEPK, PEFMEPK, and CTFMEPK fractions showed significant peripheral analgesic activity at a dose of 400 mg/kg body weight with percentage of inhibition of acetic acid-induced writhing 77.67 (p<0.001), 33.50 (p<0.001), and 40.29 (p<0.001), respectively, compared to the standard dichlofenac (60.68%, p<0.001) group. The hypoglycemic properties of MEPK, PEFMEPK, and CTFMEPK extracts were evaluated in normoglycemic mice where the reduction of blood glucose level after 30 min of glucose load were 69.85%, 78.91%, and 72.73%, respectively, and for standard glibenclamide, the reduction was 72.85%. All results were significant (p<0.05). In the case of the CNS depressant activity by phenobarbitone-induced sleeping time test, the crude ME significantly reduced sleep latency by 57.14% and increased the duration of sleep by 63.29% compared to the control, which were comparable to that of standard diazepam (65.71% and 77.62%, respectively). Among all the extract and fractions, methanolic extract showed the maximum antidiarrheal effect. The methanolic extract at 200 mg/kg dose induced a significant decrease in the total number of defecation in 4 h (69.05% of inhibition, p<0.001) and at 400 mg/kg dose showed 76.19% of inhibition (p<0.001).
Conclusions: In light of the available literature, these findings represent the first experimental investigation of biological activities of P. karka in the perspective of their traditional use.
Keywords: Phragmites karka; analgesic; anti-inflammatory; antidiarrheal; hypoglycemic activity.