Enhanced Production of Phenolic Compounds in Compact Callus Aggregate Suspension Cultures of Rhodiola imbricata Edgew.

Abstract

Rhodiola imbricata is a rare medicinal plant of the trans-Himalayan region of Ladakh. It is used for the treatment of numerous health ailments. Compact callus aggregate (CCA) suspension cultures of Rhodiola imbricata were established to counter extinction threats and for production of therapeutically valuable phenolic compounds to meet their increasing industrial demands. The present study also investigated the effect of jasmonic acid (JA) on production of phenolic compounds and bioactivities in CCA suspension cultures. CCA suspension cultures established in an optimized Murashige and Skoog medium supplemented with 30 g/l sucrose, 3 mg/l NAA, and 3 mg/l BAP showed maximum biomass accumulation (8.43 g/l DW) and highest salidroside production (3.37 mg/g DW). Upon 100 μM JA treatment, salidroside production (5.25 mg/g DW), total phenolic content (14.69 mg CHA/g DW), total flavonoid content (4.95 mg RE/g DW), and ascorbic acid content (17.93 mg/g DW) were significantly increased in cultures. In addition, DPPH-scavenging activity (56.32%) and total antioxidant capacity (60.45 mg QE/g DW) were significantly enhanced upon JA treatment, and this was positively correlated with increased accumulation of phenolic compounds. JA-elicited cultures exhibited highest antimicrobial activity against Escherichia coli. This is the first report describing the enhanced production of phenolic compounds and bioactivities from JA-elicited CCA suspension cultures of Rhodiola imbricata.

Optimization of Biomass Accumulation and Production of Phenolic Compounds in Callus Cultures of Rhodiola rosea L. Using Design of Experiments

“…To obtain callus cultures of Rhodiola species, cytokinin BAP is most often employed in combination with various auxins. Compact callus aggregate suspension cultures of Rhodiola imbricata are obtained on the MS medium supplemented with 3 mg/L NAA and 3 mg/L BAP [ 28 ]. Rhodiola quadrifida (Pall.)…”

“…We showed that when callus cultures are exposed to an elicitor, phenolic compounds emerge that are absent in the sample without treatment; their retention times are 13.6, 30.0, 33.3, and 46.0 min. The effectiveness of MJ as an elicitor has been demonstrated for many in vitro cultures, including those of Rhodiola species [ 28 , 51 , 52 , 53 , 54 , 55 , 56 , 57 ]. For example, for Rhodiola it is reported that the levels of bioactive compounds increase with MJ supplementation in a dose-dependent manner.…”

“…Various concentrations and combinations of plant growth regulators have been used to obtain callus and suspension cultures of Rhodiola species. For the induction of callus formation in these species, a combination of cytokinins and auxins is required [ 10 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ]. 6-benzylaminopurine (BAP) is one of the most widely used plant growth regulators for in vitro culture of Rhodiola .…”

“…6-benzylaminopurine (BAP) is one of the most widely used plant growth regulators for in vitro culture of Rhodiola . Cotyledons, hypocotyl, leaves, apical buds, and internode fragments, inoculated on media containing BAP (0.2–3 mg/L) in combination with indole-3-acetic acid (IAA; 0.1 mg/L) [ 24 ], α-naphthylacetic acid (NAA; 0.5–3 mg/L) [ 10 , 28 ], or 2,4-dichlorophenoxyacetic acid (2,4-D; 0.5–3.0 mg/L) [ 25 , 31 ] have been the most appropriate explant types and media constituents for induction of well-growing calluses [ 5 ].…”

“…Jasmonic acid and methyl jasmonate (MJ) are recognized as effective elicitors that trigger the biosynthesis of secondary defense compounds in callus and suspension cultures by activating the genes of secondary metabolism [ 34 ]. For example, jasmonic acid has been shown to enhance phenolic-compound production and bioactivity in a suspension culture of R. imbricate [ 28 ].…”