Response of Saponaria officinalis L. hairy roots to the application of TiO2 nanoparticles in terms of production of valuable polyphenolic compounds and SO6 protein.

Saponaria officinalis L. is a perennial plant from the Caryophyllaceae family whose various parts are used in traditional medicine as the treatment agent of skin diseases, blood purifier, diuretic, sudorific, and bile purifier. The cultivation system of hairy roots is a proper alternative for improving the valuable pharmaceutical compounds production compared to other in-vitro methods. The extensive nanotechnology applications in hairy roots cultivation is a sustainable production foundation to produce such active elements. In this study, the effect of various concentrations of titanium dioxide nanoparticles (TiO2 NPs) (0, 10, 20, 30, 50 mg L-1) with two treatments (24 and 48 h) was examined on the growth level, antioxidant capacity, total phenol and flavonoid contents, antioxidant enzyme activities, certain polyphenol compounds and SO6 protein in hairy roots of S. officinalis. According to the results, the maximum (3.09 g) and minimum (0.96 g) fresh weight (FW) of hairy roots were observed in treated culture media with 10 and 20 mg L-1 of TiO2 NPs after 24 and 48 h of exposure times, respectively. The highest rate of total phenol (9.79 mg GLA g-1 FW) and total flavonoid contents (1.06 mg QE g-1 FW) were obtained in the treated hairy roots with 50 and 30 mg L-1 of nano elicitor in 24 and 48 h of treatments, respectively. The maximum level of most polyphenols, such as rosmarinic acid, cinnamic acid, and rutin, was produced in 24 h of treatment. The use of TiO2 NP for 48 h with 50 mg L-1 concentration showed the highest production level of SO6 protein.

Improved tropane alkaloid production and changes in gene expression in hairy root cultures of two Hyoscyamus species elicited by silicon dioxide nanoparticles.

Species of Hyoscyamus are rich sources of medicinally important tropane alkaloids, which have anticholinergic, antispasmodic and sedative effects and are competitive inhibitors of acetylcholine. The application of nanotechnology and nanomaterials for elicitation is rapidly expanding and recent research indicates that silicon dioxide nanoparticles (SiO2 NPs) can be used as an efficient elicitor to increase the production of hyoscyamine and scopolamine in Hyoscyamus species. Thus, in this work, the effect of SiO2 NPs (0, 25, 50, 100 and 200 mg L-1) with two treatment times (24 and 48 h) on the growth rate, total phenol and flavonoid content (TPC, TFC), antioxidant enzyme activity, tropane alkaloid yield and pmt (putrescine N-methyltransferase) and h6h (hyoscyamine 6-hydroxylase) gene expression levels in hairy roots of two Hyoscyamus species (H. reticulatus and H. pusillus) was investigated. The highest TPC and TFC accumulation was obtained in H. reticulatus elicited by SiO2 NPs (100 and 200 mg L-1), respectively, at 24 h of treatment. High-performance liquid chromatography (HPLC) revealed the highest amount of hyoscyamine (140.15 µg g-1 FW) and scopolamine (67.71 µg g-1 FW) accumulated in H. reticulatus transformed roots treated with 100 mg L-1 SiO2 NPs at 24 h, with a respective increase of 1212% and 272% compared to non-treated roots. In H. pusillus, the highest hyoscyamine (7.42 µg g-1 FW) and scopolamine (15.56 µg g-1 FW) production (about 82% and 241% higher, respectively, compared to the lowest amounts) was achieved with 25 and 100 mg L-1 SiO2 NPs, respectively, at 48 h of treatment. Semi-quantitative RT-PCR analysis determined the highest expression level of pmt and h6h genes in H. reticulatus transformed roots supplemented with 100 mg L-1 SiO2 NPs.