| Summary: | The present study was aimed at determining total phenolic and flavonoid contents and studying the antioxidant activity of ginger (Zingiber officinale Rosc.) rhizome and callus, 6-gingerol and 6-shogaol and callus treated with elicitors. Petroleum ether (PE) and chloroform: methanol (1:1, v/v) (CM) extracts were prepared by maceration. Highest total phenolic content was obtained from the CM extract (60.34 ± 0.43 mg gallic acid/g) of rhizome while callus showed lower content detected in the CM extract (33.6 ± 0.07 mg gallic acid/g). Flavonoids were only detected in rhizome (CM extract 40.25 ± 0.21 mg quercetin/g). Both rhizome extracts exhibited good antioxidant activity with higher activity recorded in PE extract (IC50 value 8.29 ± 1.73 μg/mL). Callus extracts revealed lower antioxidant activity (IC50 value 1265.49 ± 59.9 μg/mL obtained from CM extract). 6-gingerol and 6-shogaol displayed high antioxidant activity in both assays with IC50 4.85 + 0.58DPPH and 5.35 ± 0.33ABTS μg/mL for the former and IC50 7.61 ± 0.81DPPH and IC50 7.05 ± 0.23ABTS μg/mL for the latter. Treatment of callus with elicitors showed significant (p < 0.05) effects in enhancing phenolic content and related antioxidant activity. The highest significant increase in phenolic content (37% and 34%) and antioxidant activity in DPPH assay (34% and 30%) was observed in callus treated with 100 mg/L yeast extract and 50 mg/L salicylic acid respectively. Therefore, studying the effect of the elicitation of ginger cultured tissues in phenolic accumulation would be of immense importance for pharmacological, cosmetic and agronomic industries. Keywords: Ginger, Antioxidant activity, Elicitors, Yeast extract, Salicylic acid, Glycine
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