Antioxidant phenolic constituents, antimicrobial and cytotoxic properties of Stachys annua L. from both natural resources and micropropagated plantlets

Abstract

An efficient micropropagation protocol was developed to produce Stachys annua plantlets and the extracts obtained from both micropropagated and naturally growing individuals were evaluated for their possible antimicrobial, antioxidant and cytotoxic activities. Mean number of shoot (4.5 +/- 0.54 per explant) and node number (4.56 +/- 0.5 per explant) as well as biomass yield based on fresh (0.29 +/- 0.02 gm per explant) and dry weight (0.029 +/- 0.003 gm per explant) were found to be the highest on MS medium with 6-BA, whilst the highest mean shoot length (36.65 +/- 1.58 mm) was obtained from MS medium containing 2iP. Hexane extracts from both sources showed activity against Staphylococcus aureus whilst methanol extracts of micropropagated plantlets exerted activity on Pseudomonas aeruginosa. In antioxidant activity assays, the best antioxidant activity was up to IC50 9.41 mg/mL in DPPH and 1409.5 (mg/100 gm trolox equivalent) was found in FRAP. Extracts from natural plantlets showed higher cytotoxic activity micropropagated ones, with IC50 of 0.099 mu g/mL and IC(50)of 0.211 mu g/mL on HeLa cells, respectively. Total phenolics ranged from 87.47 to 605.12 in micropropagated samples while 771.46 (mg/100 gm gallic acid equivalent) in natural resources.