Screening, in-vitro propagation and bioaugmentation of Ceratotheca triloba for the production of secondary metabolites

Abstract

Ceratatheca triloba (Bernh.) E. Mey. Ex Hook. f. is one of four species that is common to the summer rainfall areas in South Africa, especially the grasslands. It is used in traditional medicine to treat stomach cramps, nausea, fever and diarrhea. Like many other plants used in the traditional medicine system, these uses are not justified through scientific investigations. This study was undertaken to characterize the functionality of the main bioactive compounds from Ceratatheca triloba. This was achieved by isolating and identifying predominant chemicals from the non polar extracts using conventional chromatography techniques. Once identified the crude extracts and identified compounds were tested for their antimicrobial, anti-oxidant activity, anti-inflammatory activity and anticancer activity. This was followed by investigating the safety of the crude extracts and the purified compounds by the Brine shrimp lethality assay, and its toxicity to HepG2 cells and the Salmonella mutagenecity test. For large scale production, we set up a protocol to produce 9, 10 anthracenedione in a cell suspension culture system.

Following the complete chemical profile of the roots, stems, flowers and leaves the predominant compounds were isolated, characterized and identified by UV-Vis, IR, EI-LCMS and NMR (COSY, HMQC, HMBC and DEPT). Three anthraquinone derivatives and one steroid, 9, 10 anthracenedione, 1-hydroxy-4-methylanthraquinone, 5, 8-dimethoxy-2, 3, 10, 10a-tetrahydro-1H-phenanthrene-4, 9-dione and androst-5-ene-3, 17, 19-triol were determine by analysis of spectral data (UV, 1H NMR, 13C NMR and EI-LC-MS)

9, 10 anthracenedione and 1 hydroxy-4-methylanthraquinone showed antibacterial activity against S.aureus, M. luteus, B cureus and E. coli. Due to the synergistic effect of the individual compounds, the crude extract exhibited good potency (>500) against S.aureus and M. luteus, medium potency against E. coli. and S. typhimurium (<100) and very low potency against B cureus (<10). Although a similar trend was observed for 9, 10 anthracenedione and 1 hydroxy-4-methylanthraquinone unlike the crude extract. A very low potency against S.aureus for 9, 10 anthracenedione and a high potency for 1 hydroxy-4-methylanthraquinone. Thus 9, 10 anthracenedione is an effective drug against E. coli and S. typhimurium and 1 hydroxy-4-methylanthraquinone is effective against S.aureus and M. luteus. The crude root extracts and 9, 10 anthracenedione, 1 hydroxy-4-methylanthraquinone, 8-dimethoxy-2, 3, 10, 10a-tetrahydro-1H-phenanthrene-4 showed a ± 50% reduction of the free radicals. No anti-inflammatory activity was observed. The purified extracts showed moderate toxicity against HepG2 cells at high concentrations and no toxicity was observed against brine shimp larvae. No mutagenecity was observed with the crude extracts using the Ames test. All purified and crude extracts showed potent inhibition of the human topoisomerase II enzyme.

In conclusion, although this study does not indicate any relationship to its traditional usage it provides valuable information that paves a way for commercial exploitation of C. triloba. 9, 10 anthracenedione and 1 hydroxy-4-methylanthraquinone can be used as antibacterial agents. Their antioxidative potential can be exploited for anti-cancer as in many cancers reactive oxygen species are implicated in the aetiology of these cancers. Furthermore, in this study 9, 10 anthracenedione was produced from both callus cultures and cell suspension cultures. This compound demonstrates potent anti-topoisomerase II activity which is vital to cancer treatment. Thus, the synergistic effect of 9, 10 anthracenedione and 1 hydroxy-4-methylanthraquinone as antibacterial, anti-oxidative and anti-cancer compounds demonstrate the importance of C. triloba.