In vitro propagated Mentha rotundifolia (L.) Huds and antioxidant activity of its essential oil

Mentha rotundifolia (L.) Huds is an aromatic plant used for its medicinal values. This study aims to select appropriate conditions for in vitro propagation of M. rotundifolia (L.) Huds and to evaluate yield and antioxidants activity of its essential oils (EOs).

The explants were cultured on Murashige and Skoog (MS) medium containing different concentrations of growth regulators 6-benzylaminopurine (BAP) and Gibberellin (GA₃).

Hydrodistillated EOs obtained from acclimatized and mother plant, were evaluated for their antioxidant activity. Tests were performed on DPPH free radical-scavenging, ABTS and CUPRAC assays.

Shoot induction and multiplication were successfully carried out on MS medium supplemented with the following hormones combinations: 1 mg/l BAP, 1 mg/l GA₃ and 0.5 mg/l BAP, 0.5 mg/l GA₃, respectively. Stem length, nodes and leaves number measured from development vitroplant were 6.89 cm, 5.22 nodes and 11.92 leaves per vitroplant, respectively.

In vitro rooted plants were successfully acclimatized at a temperature of 23 ± 2°C and a long day photoperiod with a total survival rate exceeding 95%.

EO yield of acclimated plant varied between (0.88-1.49 ml/100 g dry matter) compared to wild plant (0.73 ml/100 g dry matter). The antioxidant potential of EOs from acclimated plant showed on DPPH free radical-scavenging, ABTS and CUPRAC assays values of (IC₅₀: 4.18-24.93 mg/ml), (IC₅₀: 0.51-1.56 mg/ml) and (A_0.50: 0.34-2.71 mg/ml), respectively. In contrast, the wild plant exhibited on the same tests the values of (IC₅₀: 10.35 mg/ml), (IC₅₀: 0.12 mg/ml) and (A_0.50: 0.99 mg/ml), respectively.

The results suggest that micropropagation of M. rotundifolia (L.) Huds can be an interesting alternative for producing important plant material with the possibility to modulate EO yield and its antioxidant potential for future commercial purposes.