Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

Interactions between plant extracts and eell viability indicators during cytotoxicity testing: Implications for ethnopharmacological studies

Sze Mun Chan¹, Kong Soo Khoo², Nam Weng Sit¹

¹Department of Biomedical Science; ²Department of Chemical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Bandar Barat, 31900 Kampar, Perak, Malaysia.

For correspondence:- Nam Sit Email: sitnw@utar.edu.my Tel:+6054688888

Received: 26 September 2014 Accepted: 27 August 2015 Published: 29 November 2015

Citation: Chan SM, Khoo KS, Sit NW. Interactions between plant extracts and eell viability indicators during cytotoxicity testing: Implications for ethnopharmacological studies. Trop J Pharm Res 2015; 14(11):1991-1998 doi: 10.4314/tjpr.v14i10.6

© 2015 The authors.
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Abstract

Purpose: To compare the cytotoxicity of six medicinal plants (Acmella ciliata, Amaranthus tricolor, Coriandrum sativum, Glebionis coronaria, Kyllinga brevifolia and Tradescantia zebrina) using 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and neutral red uptake (NRU) assays.

Methods: Hexane, chloroform, ethyl acetate, ethanol, methanol and water extracts were obtained for each plant by sequential solvent extraction. Cytotoxicity was evaluated in triplicate, from 640 to 5 µg/mL, two-fold, serially on monkey kidney epithelial (Vero) cells.

Results: The hexane, chloroform and ethyl acetate extracts of the six plants were more toxic to the Vero cells compared to the ethanol, methanol and water extracts. Thirty one percent (11/36) and 75 % (27/36) of the extracts showed significant cytotoxicity (p < 0.05) in MTT and NRU assays, respectively. The 78, 52 and 7 % cytotoxicity levels detected in 27 extracts using the MTT assay were significantly (p < 0.05) underestimated at 640, 320 and 160 µg/mL, respectively, using NRU assay. Nine extracts from five plants exhibited significantly lower (p < 0.05) 50 % cytotoxic concentration (CC₅₀) when NRU assay was employed compared to MTT assay. At 640 µg/mL, 10 of the 21 extracts were also found to react chemically with MTT, causing a 2.0 – 29.1-fold increase in the absorbance value (550 nm) compared to control.

Conclusion: The plant extracts of A. ciliata, A. tricolor, C. sativum, G. coronaria, K. brevifolia and T. zebrina show concentration- and extraction method-dependent cytotoxicity using MTT and NRU assays. NRU assay appears to be more sensitive and reliable than MTT assay for cell viability evaluation of the plant extracts.

Keywords: Acmella ciliata, Amaranthus tricolor, Coriandrum sativum, Glebionis coronaria, Kyllinga brevifolia and Tradescantia zebrina, Extraction, Medicinal pla