Differential Production of Phenylpropanoid Metabolites in Callus Cultures of Ocimum basilicum L. with Distinct In Vitro Antioxidant Activities and In Vivo Protective Effects against UV stress

Abstract

Ocimum basilicum L. (Purple basil) is a source of biologically active antioxidant compounds, particularly phenolic acids and anthocyanins. In this study, we have developed a valuable protocol for the establishment of in vitro callus cultures of O. basilicum and culture conditions for the enhanced production of distinct classes of phenylpropanoid metabolites such as hydroxycinnamic acid derivatives (caffeic acid, chicoric acid, rosmarinic acid) and anthocyanins (cyanidin and peonidin). Callus cultures were established by culturing leaf explants on Murashige and Skoog medium augmented with different concentrations of plant growth regulators (PGRs) [thidiazuron (TDZ), α-naphthalene acetic acid (NAA), and 6-benzyl amino purine (BAP)] either alone or in combination with 1.0 mg/L NAA. Among all the above-mentioned PGRs, NAA at 2.5 mg/L led to the highest biomass accumulation (23.2 g/L DW), along with total phenolic (TPP; 210.7 mg/L) and flavonoid (TFP; 196.4 mg/L) production, respectively. HPLC analysis confirmed the differential accumulation of phenolic acid [caffeic acid (44.67 mg/g DW), rosmarinic acid (52.22 mg/g DW), and chicoric acid (43.89 mg/g DW)] and anthocyanins [cyanidin (16.39 mg/g DW) and peonidin (10.77 mg/g DW)] as a function of the PGRs treatment. The highest in vitro antioxidant activity was determined with the ORAC assay as compared to the FRAP assay, suggesting the prominence of the HAT over the ET-based mechanism for the antioxidant action of callus extracts. Furthermore, in vivo results illustrated the protective action of the callus extract to limit the deleterious effects of UV-induced oxidative stress, ROS/RNS production, and membrane integrity in yeast cell culture. Altogether, these results clearly demonstrated the great potential of in vitro callus of O. basilicum as a source of human health-promoting antioxidant phytochemicals.

Interactive Effect of Melatonin and UV-C on Phenylpropanoid Metabolite Production and Antioxidant Potential in Callus Cultures of Purple Basil (Ocimum basilicum L. var purpurascens)

“…For germination, all vials were kept in the growth chamber under a light cycle (16/8 h light/dark) and temperature (25 ± 2 • C). Callus cultures were established using leaf explants (0.5 cm 2 ) from 28-days-old plantlets (in vitro-derived) cultured on MS media additionally supplied with NAA (2.5 mg/L), as optimized earlier by Nazir et al [8]. Vials were shifted to the growth room for callogenesis.…”

“…These compounds are believed to have significant roles in stress-coping mechanisms and help plants to interact with their environment. The potential applications of these compounds as antioxidant molecules is of great important to humans [7,8]. The overexploitation and depletion of natural resources is the major concern of the world today.…”

Almond Skin Extracts and Chlorogenic Acid Delay Replicative Aging by Enhanced Oxidative Stress Response Involving SIR2 and SOD2 in Yeast

“…The dihydrorhodamine-123 (DHR-123) fluorescent dye (Sigma-Aldrich, Saint-Quentin Fallavier, France) was used to determine the level of reactive oxygen and nitrogen species as described by Nazir et al [23]. Approximately 10 8 yeast cells grown in the presence of AE, CHL or RES or DMSO (control cells) were washed twice with PBS, and then resuspended in PBS containing 0.4 μM DHR-123 and incubated during 10 min in the dark at 30 °C.…”

“…UV-induced oxidative stress in yeast strain DBY746 (MATα leu2-3,112 his3Δ1 trp1-289a ura3-52 GAI+) grown on YPD medium was obtained as described by Nazir et al, [23]. Yeast cells were irradiated with 106.5 J/m 2 UV-C (254 nm) under a Vilber VL-6.C filtered lamp (Thermo Fisher Scientific, Villebon-sur-Yvette, France).…”

“…Overall, the previous results suggest that AE and CHL may extend the replicative lifespan of the yeast through an antioxidant mechanism. The impact of UV-C-induced oxidative stress on DBY746 yeast was examined to test this hypothesis using our published protocol [6,23,26]. The resulting yeast survival, estimated with a quantitative colony counting assay [49], and ROS/RNS production are presented in Figure 4.…”