Twenty-five species of the lichen family Graphidaceae have been investigated for tyrosinase-inhibitory activity. Tyrosinase-inhibiting material was extracted with solvents methanol, acetone, ethanol, dimethyl sulphoxide in water, and with water only. Methanol has been found to be suitable for extracting adequate amounts of tyrosinase-inhibiting component from the natural thallus. The lichen species such as Graphina glaucorufa, Graphina multistriata, Graphina salacinilabiata, Graphis assamensis, Graphis nakanishiana, and Phaeographopsis indica, have shown inhibition of tyrosinase over a range of 30-78%. Half-inhibiting concentration (IC(50), microg/ml) has been found to be much lower than the standard tyrosinase inhibitors and thus can compete with other commercially available tyrosinase inhibitors. The extracts of these species have been found to be stable at 4 degrees C.
Objective: To study the antisecretory and antiulcer activity of Asparagus racemosus Willd. (methanolic extract) and its action against indomethacin (a non-steroidal anti-inflammatory drug) plus pyloric ligation (PL)-induced gastric ulcers in rats.
Method: Indomethacin plus PL-induced gastric ulceration model was used in the study.
Results: Treatment with Asparagus racemosus (Shatavari) crude extract (100 mg/kg/day orally) for fifteen days significantly reduced ulcer index when compared with control group. The reduction in gastric lesions was comparable to a standard antiulcer drug Ranitidine (30 mg/kg/ day orally). Crude extract also significantly reduced volume of gastric secretion, free acidity and total acidity. A significant increase in total carbohydrate (TC) and TC/total protein (TP) ratio of gastric juice was also observed. No significant change in the total protein was noted.
Conclusion: Asparagus racemosus was found to be an effective antiulcerogenic agent, whose activity can well be compared with that of ranitidine hydrochloride. The results of this study suggest that Asparagus racemosus causes an inhibitory effect on release of gastric hydrochloric acid and protects gastric mucosal damage.
To elucidate the mechanism of inhibitory action of peony root extract on pentylenetetrazol-induced bursting activity, effects of peony root extract on the iberiotoxin-sensitive large conductance calcium-activated potassium (BKCa) current that plays an essential role in the production of bursting activity were investigated. Peony root extract showed a clear inhibitory effect on the iberiotoxin-sensitive calcium-activated potassium current. Peony root extract also showed clear inhibitory effects on spontaneous bursting activity and BKCa current in the cerebral cortical neurons of the EL mouse, a hereditary epilepsy animal model. These results together with our previous studies, including the protective effect against neuron damage, indicate that peony root extract is a promising herbal drug for inhibition of convulsions.
The antihyperglycemic effect of ethanolic extract of flowers of Musa sapientum (Musaceae), a herb (used in Indian folklore medicine for the treatment of diabetes mellitus) in alloxan induced diabetic rats. Oral administration of the ethanolic extract showed significant (p < 0.001) blood glucose lowering effect at 200 mg/kg in alloxan induced diabetic rats (120 mg/kg, i.p.) and the extract was also found to significantly (p < 0.001) scavenge oxygen free radicals, viz., superoxide dismutase (SOD), catalase (CAT) and also protein, malondialdehyde and ascorbic acid in vivo. Musa sapientum induced blood sugar reduction may be due to possible inhibition of free radicals and subsequent inhibition of tissue damage induced by alloxan. The antidiabetic activity observed in this plant may be attributed to the presence of flavonoids, alkaloids, steroid and glycoside principles.