Large scale screening of selected Egyptian plant extract's against human colon, liver, breast and lung carcinoma cell lines for detection of antitumor activity in-vitro.

Abstract

The aim of this study is to identify Egyptian plant extracts with anticancer, antioxidant and anticandidal activities. Thus, 40 plants belonging to 6 families were collected from different areas in Egypt and yielded 50 extracts. These extracts were screened for the previously mentioned activities. 1- Anticancer activity The anticancer effect of methanol extracts of 50 plant parts against monolayers of the human cancer cell lines, A549 (lung carcinoma) and HCT-116 (colon carcinoma) HepG2 (liver carcinoma) and MCF-7 (breast carcinoma), were investigated. Cultures of these cell lines were treated with extracts firstly at one concentration of 100μg/ml and the results showed that 11 plant extracts possessed high activity (75-100%) against at least one cancer cell line. These were:  Anacardium occidentale with 100% cytotoxicity against HepG2, MCF-7, A549 and HCT-116 cell lines.  Pleiogynum solandri with 75, 86 and 75% cytotoxicity against HepG2, MCF-7 and A549 respectively.  Pistachio terebinthus with cytotoxicity 97% against HepG2 and MCF-7.  Harpophyllum caffrum exhibited cytotoxic activity against HepG2, MCF-7, A549 and HCT- 116 (81, 75, 75 & 79% respectively).  Albizzia stipulata leaves extract with 89% cytotoxicity at 100μg/ml against A549. Summary 119  Derris robusta with76% cytotoxicity against A549.  Bauhinia variegate exhibited cytotoxic activity against MCF-7(83%).  Adenanthera pavonina bark extract with cytotoxicity against HepG2 and MCF-7 (75 and 91% respectively).  Albizzia stipulate branch extract showed cytotoxicity against HepG2 and MCF-7 (75 and 86% respectively).  Derris elliptica with cytotoxicity 93, 76 and 90% against HCT-116, HepG2 and MCF-7 respectively.  Hyphaene thebaica showed cytotoxicity against A549 and MCF-7 (87 and 89 % respectively). 1.1. Dose response study to calculate the IC50 values:- For the most active extracts which showed high cytotoxic effect against different human cancer cell lines, dose response study was performed to calculate the IC50 values (secondary screening). The results showed 2 extracts with least IC50 values (IC50 <30μg/ml). These included: Harpophyllum caffrum leaves extract and Albizzia stipulate branch extract. The other plant extracts showed moderate IC50 values (IC50 > 30-45 μg/ml). 1.2. Selectivity index (SI):- The 11 extracts which possessed high activity against cancer monolayers have been further tested for safety on human normal cell line BJ-1 to calculate their SI values. 9 extracts were relatively safe to normal cells (SI >1). 1.3. In vitro cytotoxic effect on 3 D spheroids cancer cells:- The 11 active extracts which possessed high anticancer activity (75% -100%) against cancer monolayers were screened for their cytotoxicity on the same responsive cell line but grown as 3D spheroids to select the most active extract(s) to be subjected to initial fractionation. The Summary 120 results showed 6 extracts having moderate to high cytotoxic effect on 3D cancer cells. These were:  Albizzia stipulate leaves extract with moderate cytotoxic effect against lung carcinoma cell line (45%).  Hyphaene thebaica bark exract. With cytotoxicity (55 and 63%) against lung carcinoma and breast carcinoma cells respectively.  Harpophyllum caffrum leaves extract with moderate cytotoxicity 40% against colon carcinoma and liver carcinoma cells  Pistachia terebinthus branch extract with cytotoxic effect against liver carcinoma and breast carcinoma cells (65 &70% respectively)  Albizzia stipulate branch extract with cytotoxic effect against liver carcinoma and breast carcinoma cells (60 &53% respectively)  Derris elliptica leaves extract with cytotoxicity 60% against breast carcinoma cells 2- Initial Fractionation:- The 6 spheroid active extracts were considered the most promising in anticancer activity and 5 of them were subjected to initial fractionation (no enough material was available for the sixth plant). The results of initial fractionation showed the following:  In case of Albizzia stipulate leaves extract, the bioactivity was mainly transferred to the aqueous methanol fraction (F-7).  For Hyphaene thebaica bark and Pistachia terebinthus branch extracts, the hexane fraction (F-6) was found to be the most active fraction.  For Harpophyllum caffrum leaves extract, the methylene chloride fraction (F-4) was the most active fraction.