Pharmacological and phytochemical screening of two Hyacinthaceae species: Scilla natalensis and Ledebouria ovatifolia.

Aqueous, ethanolic, dichloromethane and n-hexane extracts of Scilla natalensis Planch. and Ledebouria ovatifolia (Bak.) Jessop bulbs (Hyacinthaceae) were screened for antibacterial, anti-inflammatory, antischistosomic, anticancer and anthelmintic activity. Poor antibacterial activity against both Gram-positive and Gram-negative bacteria was shown with S. natalensis extracts. Good antibacterial activity was shown by the ethanolic and dichloromethane extracts of L. ovatifolia against Gram-positive bacteria. In the anti-inflammatory screening, the dichloromethane and hexane extracts of S. natalensis resulted in good inhibition against both COX-1 and COX-2. Ethanolic extracts had the highest inhibitory effect against nematodes in the anthelmintic assays. Poor anti-inflammatory and anthelmintic activity was found with L. ovatifolia. Aqueous extracts of S. natalensis had good activity against Schistosoma haematobium, with a minimum inhibitory concentration of 0.4 mg ml(-1). Aqueous extracts of fresh L. ovatifolia bulb material were found to be lethal to S. haematobium at a concentration of 1.6 mg ml(-1). The phytochemical screening of S. natalensis bulbs revealed the presence of saponins and bufadienolides within the bulbs. Bulbs of L. ovatifolia contained bufadienolides.