Enhancement of phenolic compounds production in in vitro grown Rumex cyprius Murb.

Abstract

Plant tissue culture can readily be applied to the field of medicinal plants and secondary metabolites production. In this study, in vitro propagation protocol of Rumex cyprius Murb. was established. The highest shoot multiplication rate was observed from explants grown on MS medium supplemented with 1.5 mg/L BA (7.8 shoots per explant). For rooting, the maximum root induction rate was observed on MS medium supplemented with 1.5 mg/L IBA or 1.0 mg/L NAA. The longest roots were observed for plants grown on MS medium supplemented with 1.5 mg/L IBA. For callus induction, leaves from in vitro grown plants were cultured in various levels of 2,4-D or different combinations of BA and NAA. The highest fresh weight (5.86 g) of calli was observed at 1.5 and 0.5 mg/L BA and NAA, respectively. The second part of this work investigated the effects of abiotic factors (NaCl and Mannitol) and biotic factors (Yeast extract and Chitosan) on secondary metabolites accumulation of in vitro grown R. cyprius. Phenolic compounds were extracted, and the individual phenolic compounds and antioxidant activity of the extracts were determined of in vitro grown R. cyprius. The total phenol content and antioxidant activity increased significantly by the pervious factors. Reversed high-pressure liquid chromatography (RP-HPLC) was used to measure the effect of these factors on the contents of individual phenolic compound. New phenolic compounds (Gallic acid and Chlorogenic acid) not found in R. cyprius plants grown on control media were produced in R. cyprius plants grown on media supplemented with elicitors. Results indicate that using elicitors in plant tissue culture could be used to produce/enhance secondary metabolites accumulation in R. cyprius.

Effect of growth regulators on micropropagation, callus induction and callus flavonoid content of Rumex pictus Forssk

“…The highest number of shoots per explant (12.6) was induced by 2mg L −1 BAP and it was associated with high percentage of shoot induction (70%). Our results support those found by Al Khateeb et al (2017), who reported that BAP induced the best results in shoot multiplication from shoot apex of R. cyprius when compared with TDZ and KIN. In contrast, Polygonum hydropiper exhibited a preferential multiple shoot induction from shoot tip on KIN over BAP (Hasan & Sikdar, 2010).…”

“…However, IAA induced no roots from R. pictus shoots, even when applied with half-strength MS media ( Table 2), indicating that root induction may be influenced also by the suitability of the exogenously added growth regulator. The superiority of IBA as effective auxin for inducing in vitro rooting over IAA and NAA was previously pointed out (Moharami et al, 2014;Swain et al, 2016 andAl Khateeb et al, 2017). IBA was reported to be the most successful auxin in root formation in several plant species (Thomas, 2007;Shekhawat et al, 2015 andDewir et al, 2016), however an increase of IBA level (up to 2mg L −1 ) decreased the percentage of root induction, root number and root length of R. pictus (Table 2).…”

“…However, in most cases, the highest callus frequency was The selection of proper combination of plant growth regulators was necessary to get high percentage of callus induction and high mass production. Previous studies found that callus, of other medicinal plants belong to the family Polygonaceae rather than R. pictus, grows better on media containing high cytokinin: auxin ratio (Liu et al, 2005;Wang et al, 2011 andAl Khateeb et al, 2017). On the other hand, the combination of 1mg L −1 2,4-D and 0.4mg L −1 BAP was mostly the best combination for callus induction and proliferation, since it significantly induced the highest callus biomass (1.15 and 1.09g fresh wt and 0.079 and 0.09g of dry wt) from both cotyledonary and foliage leaves explants of R. pictus, respectively (Table 3).…”

“…A main factor that masters the growth and success of the in vitro plant culture is growth regulators; auxins and cytokinins. The cytokinin, 6-benzylaminopurine (BAP), was found to induce in vitro regeneration of medicinal plants either alone (Al Khateeb et al, 2017) or when it was combined with auxins such as IBA (Tabin et al, 2017), NAA (Swain et al, 2016) or IAA; indole-3-acetic acid (Moharami et al, 2014 andŚlesak et al, 2014). Moreover, the involvement of cytokinins in callus culture media and their contribution in callus induction and proliferation are well established.…”

“…Combination and concentration of the applied auxin and cytokinine were reported to strongly influence the biosynthesis and accumulation of flavonoids in the cultured plant cell (Bota & Deliu, 2015). Plant tissue culture techniques have been applied to some Rumex species other than R. pictus such as R. vesicarius (Abo El-Soud et al, 2011;El-Shafey et al, 2016 andSayed et al, 2017), the hybrid sorrel Rumex tianschanicus x Rumex patientia (Ślesak et al, 2014), R cyprius (Al Khateeb et al, 2017) and R. nepalensis (Bhattacharyya et al, 2017). However, to our knowledge, there have been no previous reports investigating the in vitro culture of R. pictus.…”