Phytochemical Study of Selected Dracaena Species for Anti-inflammatory and Anticancer Principles

Abstract

Chronic inflammation is associated with the onset of chronic disorders such as cancer. The currently available anti-inflammatory and anticancer drugs are associated with diverse undesirable side effects. Hence, search for new drugs with better efficacy and less toxicity against these associated inflictions is necessary. In this study, three Dracaena species from Kenya namely: Dracaena usambarensis, Dracaena aletriformis and Dracaena steudneri were phytochemically investigated and tested for their anti-inflammatory and anticancer potencies. The different parts of the plants were extracted (MeOH/CH2Cl2 (1:1)) and chromatographically separated using silica gel and Sephadex LH-20 as solid matrix followed by purification on chromatotron and semi-preparative HPLC). Structure elucidation of isolates were deduced using a panel of spectroscopic (NMR, UV, IR, optical rotation, CD and X-ray analysis) and spectrometric (HRESIMSn) methods. The isolated compounds and the standard drug ibuprofen were evaluated for their anti-inflammatory potency against four inflammatory biomarkers (IL-1β, IL-2, GM-CSF and TNF-α). In addition, the cytotoxicity of the crude extracts and isolates were determined by resazurin reduction assay in comparison with the standard drug doxorubicin. Phytochemical analysis of the stems of Dracaena usambarensis afforded eleven secondary metabolites out of which five are novel (176  180). The roots of the same plant yielded seven secondary metabolites of which two were new (186 and 189). Phytochemical investigation of the whole plant of Dracaena aletriformis afforded three previously reported phenolic amides (193  195). The seeds and leaves of Dracaena steudneri afforded twenty eight secondary metabolites including six novel flavonoids (203  208). A total of fifty (50) secondary metabolites including thirteen (13) novel ones were reported from these plants. Among the tested compounds, at a concentration of 100 μM, compounds 180 (1.61 to 27.53% of LPS control), 182 (14.48 to 58.04% of LPS control), 184 (0.06 to 11.61% of LPS control) and 216 (0.35 to 27.53% of LPS control), showed a clear decrease of all the cytokines compared to the standard drug, ibuprofen. At a concentration of 10 μM, compound 200 displayed strong cytotoxicity against both leukemia cell lines: CCRF-CEM (IC50 of 7.88 ± 0.74 μM) and CEM/ADR5000 (IC50 of 5.28 ± 0.85 μM), while compound 213 had an IC50 values of 8.80 ± 0.74 μM and 3.31 ± 0.36 μM μM, respectively. Moderate cytotoxicity was observed for compound 186 against CCRF-CEM (IC50 of 40.43 Dracaena exhibited strong to moderate anti-inflammatory and cytotoxic potencies and can be considered as lead compounds for drug discovery.