Fresh seeds of Raphanus sativus L. and air-dried leaves and roots of Schefflera odorata B. were extracted with 95% ethanol by percolation and fractionated with chloroform and water, Extracts after concentration were tested for its cytotoxicity activity on five cell lines, namely: A549 (adenicarcinoma of the lung), SL-6 (large cell of the lung), Calu-1 (Squamous carcinoma of the lung), Hep-2 (epidermoid carcinoma of the larynx) and L929 (mouse fibroblast) used as the negative control.
Collaborative work on the lima-lima leaves and roots extracts were done on other cell lines by Prof. Cordell of University of Illinois in Chicago. These cell lines were BCA-1 (breast cancer cells),LuC1 (lung cancer cells), COL-1 (colon cancer cells), KB-3 (oral epidermoid carcinoma cells) and LN CaP, FGC, Crl adenocarcinoma of the prostate). Taxol was used as the positive test control drug after 3 days of drug exposure, cells were harvested, developed or assayed using MTT dye. From these data inhibition concentration at 50% (IC50) values were derived for plant extracts which showed cell killing 50% or potential activitiy in each cell line.
The results showed that Raphanus sativus L. alcoholic, chloroform and aqueous extracts were relatively noncytotoxic to all cell lines tested at 1 to 200 ug/ml. The % cell survival ranges from 70 to 100% at 1 to 100 ug/ml drug concentration. Hence, it had a relatively high LD50. Schefflera odorata B. leaves and roots have IC5020 ug/ml for all cell lines tested with the extracts. AT IC50 20 ug/ml, the following relative sensitivity were established: alcoholic leaf extract to Calu-1 and A549, aqueous leaf extract to A549 at a relatively high dose, alcoholic leaf extracts to calu 1, and chloroform root extract to SL-6.
Other extract showed percentage cell survival 50% compared to other cell lines. IC50 of the cell lines tested by Prof. Cordell yield 20 ug/ml. Though, the extracts have exhibited relative sensitivity to some cell lines tested at a dose of 20 ug/ml, it did not provide the level of cytotoxicity that is needed for a novel anti-tumor agent on the specific type of human tumor determined.
The required dose or IC50 for a potential agent is a set at 20 ug/ml as established by the American National Cancer Institute. However, it should be noted that this study refers to direct cell killing as the in-vitro anti-tumor screening method and mechanism of action.
Studies using other molecular mechanism of cytotoxic action and in vitro or in vivo screening procedure, are recommended. Further cytotoxicity test are also recommended especially on other types of cell lines derived from other human cancer as sensitivity due to selectivity could be a factor.