Photosynthetic pigments and phenolic potential of Rhodiola rosea L. from plant communities of different ecology and geography

Abstract

Introduction. Longitudinal studies of human activity and metabolism revealed various anti-inflammatory, immunomodulatory, antistress, antioxidant, and adaptogenic properties of such secondary plant metabolites as phenolic compounds and pigments. Human cells cannot synthesize these compounds. Therefore, food biotechnology requires new data on the photosynthetic potential of plants with good functional prospects. The research objective was to study the qualitative and quantitative profile of biologically active compounds of Rhodiola rosea L. harvested from various plant communities in order to define the potential of their extracts and minor compounds for food technologies. Study objects and methods. The research featured three communities of Rhodiola rosea L. originally located in ecologically and geographically different habitats. They were introduced into Kuzbass from the Kuznetsk Alatau, Gorny Altai, and the Tunka alpine tundra belt in Buryatia. The experiment began in 2018, when the rhizomes were dissected into equal shares of 40–42 g and placed in a medicinal plant nursery. The methods of high-performance liquid (HPLC) and thin-layer (TLC) chromatography were used to study the biologically active substances in the plant biomass. The photosynthetic pigments were detected using the spectrophotometric method. The obtained data underwent a statistical analysis based on Statistica 6.0 software. Results and discussion. The sample from the Gorny Altai community revealed twelve biologically active substances. Its rhizomes appeared rich in gallic acid with the maximum content (mg/g) of 10.26 ± 2.31, rosein (20.45 ± 3.46), daphneticin (13.80 ± 2.30), and salidroside (28.16 ± 2.27). The tops demonstrated the maximum content (mg/g) of astragaline (38.94 ± 2.21), tricine (13.07 ± 0.72), tricine-5-O-β-D-glucopyranoside (35.25 ± 1.66), tricine-7-O-β-D-glucopyranoside (30.23 ± 1.45), and tyrosol (21.80 ± 1.21). The Kuznetsk Alatau sample proved to possess five biologically active substances. Its rhizomes had the maximum content (mg/g) of rosavin (16.89 ± 2.11) and salidroside (14.35 ± 2.52). The sample obtained from the Tunka ridge in Buryatia had six biologically active substances with the maximum content (mg/g) of rosavin (20.72 ± 2.11), methylgalate (39.00 ± 1.05), and cinnamaldehyde (10.15 ± 1.93) in the rhizomes. The top biomass of Rhodiola rosea L. accumulated about 0.333 mg/g of chlorophylls and synthesized 0.109 mg/g of carotenoids on average. The research established the correlation coefficients between the content of photosynthetic components with morphometric characteristics, including two positive dependences between the content of carotenoids and the number of leaves (r = 0.89 ± 0.09) and the content of carotenoids and shoot length (r = 0.96 ± 0.22). Conclusion. The samples of Rhodiola rosea L. demonstrated a good biotechnological potential for medicine and food industry. The Kuznetsk Alatau plant community proved rich in rosavin, salidroside, and methyl gallate. The Gorny Altai samples revealed high content of salidroside, gallic acid, daphnetitsin, and rosein. The Tunka samples appeared to synthesize a lot of methyl gallate, rosavin, and cinnamaldehyde. In addition, the top biomass of the Altai sample proved rich in tricine and its derivatives, astragaline and tyrosol. The research also established the possibility of commercial extraction of photosynthetic pigments from the top biomass of Rhodiola rosea L. for functional food production.