Anticarcinogenic Properties of Strobilanthes crispus Extracts and its Compounds in vitro

Plant Material
Strobilanthes cripus (Acanthaceae) was harvested from the herbal garden in Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Malaysia. The herbarium voucher specimen was identified and deposited by Mr. Ahmed Zainuddin from Department of Botany, Faculty of Science and Technology, Universiti Kebangsaan Malaysia. The voucher number for Strobilanthes crispus was AZ-6803.

Uses in Traditional Medicine
Strobilanthes crispus has been used as antidiabetic, antilytic, laxative (Sunarto, 1977), anti-AIDS, anti-leukimic (Kusumoto et al., 1992). The leaves of Strobilanthes crispus possessed high antioxidant activity (Ismail et al., 2000) and anti-hepatocarcinogenesis (Jaksa et al., 2004 ).

Previously Isolated Classes of Constituents
The compounds that were isolated from Strobilanthes crispus were ester glycosidic compounds of caffeic acid (verbascoside) (Soediro et al., 1983), 7 phenolic acid (p-hydroxy benzoic, p-voumeric, caffeic, vanilic, gentinic, ferulic and syryngic (Soediro et al., 1987), β-sitosterol and stigmasterol.

Tested Material
The leaves were dried in the oven at 60°C overnight and were grounded to fine powder. Three types of methods were applied for extraction. The first was catechin extraction (Hara, 1994). The second was single solvent extraction using ethanol, methanol and chloroform (Ali et al., 1996). The third was stepwise extraction using solvents of increasing polarity. The solvents used were hexane, chloroform, ethyl acetate and methanol. Bioactive compounds (β-sitosterol and stigmasterol) were isolated from leaves of Strobilanthes crispus which were provided by Assoc. Prof. Dr. Taufik Yap-Yun Hin.

Studied Activity
In vitro cytotoxicity of plant extracts and bioactive compounds were determined using 3-[4, 5-dimethylthiazol–2-yl]-2,5-diphenyltetrazoliumbromide) (MTT) (Roche, USA) assay.

Cell Lines
Liver cancer (HepG-2), breast cancer hormone dependent (MCF-7), breast cancer hormone non-dependent (MDA-MB-231), colon cancer (Caco-2) and normal liver cell lines (Chang liver) were obtained from the American Type Culture Collection (ATCC), Rockvilles, Maryland, USA. The medium for HepG-2 and Chang liver were Minimum Essential Medium with Earle’s salt (Gibco, USA) while Caco-2, MDA-MB-321 and MCF-7 were grown in Dulbecco’s modified Eagle medium (Gibco, USA). The cells were cultured in medium supplemented with 10% fetal calf serum, 100 IU^-1 penicillin and 100 μg mL^-1 of streptomycin (Gibco, USA) using 25 cm² flasks (Nunc, Denmark), in a 5% CO₂ incubator (Sanyo, Japan) at 37°C.