Medicinal potential of pteridophytes - an antihyperglycemic and antinociceptive activity evaluation of methanolic extract of whole plants of Christella dentata

Not much has been reported on the medicinal values of pteridophytes (fern and fern allies). Yet, a number of ferns are used in folk medicinal system and by various tribes of the Indian sub-continent (inclusive of Bangladesh) for medicinal purposes. Christella dentata is one such fern used by the folk medicinal practitioners of Bangladesh for treatment of diabetes (to lower high blood sugar levels) and for treatment of pain. It was of interest to determine whether folk medicinal uses of this fern species can be validated through modern scientific methods. Accordingly, antihyperglycemic activity evaluation of methanolic extract of whole fern was carried out through oral glucose tolerance tests in glucose-loaded Swiss albino mice. In parallel, antinociceptive activity of methanolic extract of whole ferns was evaluated in gastric pain model Swiss albino mice, where gastric pain was induced by intraperitoneal administration of acetic acid. The methanolic extract, in antihyperglycemic activity evaluation experiments, demonstrated dose-dependent significant lowering of blood sugar levels when orally administered to glucose-challenged mice at doses of 100, 200 and 400 mg per kg body weight. At these doses, the extract significantly lowered blood sugar levels by 48.02, 49.44 and 54.52%, respectively, when compared to control mice (i.e. mice administered vehicle only). The results obtained from the extract compare favorably with the result obtained with a standard antihyperglycemic drug, glibenclamide, which when administered orally at a dose of 10 mg per kg body weight, lowered blood sugar levels by 52.40%. In antinociceptive activity tests, the extract at doses of 50, 100, 200 and 400 mg per kg body weight lowered the number of gastric pain-induced writhings in mice by 42.84, 47.00, 48.96 and 51.04%, respectively. The reduction in the number of gastric writhings was both dose-dependent and statistically significant. By comparison, a standard antinociceptive drug, aspirin, reduced the number of writhings in mice by 51.04 and 67.32%, respectively, when orally administered at doses of 200 and 400 mg per kg body weight. The results not only validates the folk medicinal use of this plant for lowering of blood sugar and alleviation of pain, but also suggests that fern species should not be overlooked in the quest for discovery of newer and more efficacious drugs.