Background: Tabernaemontana divaricata (L.) R. Br. (Apocynaceae) is an evergreen usually glabrous tree found throughout the India, Australia and Polynesia. Plant roots are chewed for the relief of tooth rubbed into a thin paste and administered as vermicide, also used with lime juice to clear opacity of cornea, juice of leaves used as cooling application for wounds to prevent inflammations. The tree species has special interest because the indole alkaloids, which are commonly, used for anti-inflammatory, antifertility and antioxidant activities. The active sub-fractions and seven indole alkaloids obtained from aerial parts of T. divaricata were investigated first time for their antimicrobial, antineoplastic and cytotoxic activities.
Methods: The indole alkaloids obtained from the ethanolic extract of T. divaricata were analyzed by thin layer chromatography, high performance liquid chromatography, and mass spectroscopy. Indole alkaloids were screened for antineoplastic, cytotoxic and antimicrobial activities by using packed cell volume and microdilution methods.
Results: The observed results indicated that the strong antibacterial activity was showed by 5-oxocoronaridine at 50 μg/ml dose against K. pneumoniae and coronaridine demonstrated maximum antifungal activity against P. chrysogenum at the dose of 60 μg/ml. The tabernaemontanine and coronaridine demonstrated activity at 10 μg/kg/day and 5 μg/kg/day of 73.40% and 69.34% inhibition against Sarcoma 180. The chloroform sub-fraction (5.0 μg/ml) and coronaridine (3.0 μg/ml) showed selective cytotoxic effect against Chinese hamster V79 cells.
Conclusion: The isolated indole alkaloids exhibited antineoplastic and antimicrobial activity thus have great potential as a source of ayurvedic and allopathic products.