As in vitro plant cultures are used extensively to produce bioactive metabolites, our goal was to establish calli from Tulbaghia violacea Harv. flowers and assess the tissue phytochemically and biologically. Murashige & Skoog medium(MS) + 22.6 μM 2,4-dichlorophenoxyacetic acid +2.2 μM benzylaminopurine induced callus from flowers. Gas chromatography/mass spectrometry(GC/MS) analyses of n-hexane extracts of calli(HC) and flowers(HF) revealed 33 and 32 components(92.6 and 98.5%, respectively). Hydrocarbons were predominant in HC (55.0%), whereas a higher percentage of oxygenated compounds was found in HF(74.6%). Trans(E)-anethole(39.1%) and 16-hentriacontanone (30.3%) dominated in HF and HC, respectively. However, sulphur compounds were only detected in HF. Quantitative estimation of thiosulphinates, phenolics, flavonoids and saponins in ethanolic extracts of calli(EC) and flowers(EF) showed much higher contents in EF. Antioxidant, antimicrobial and cytotoxic screening of extracts demonstrated that EF was the most potent, followed by HF and EC; conversely, HC was inactive. Although HC and EC were less biologically active, these calli could be an alternative source of bioactive metabolites.
Keywords: GC/MS; Tulbaghia violacea Harv.; biological activities; callus cultures; secondary metabolites.