UV-C mediated accumulation of pharmacologically significant phytochemicals under light regimes in in vitro culture of Fagonia indica (L.)

Abstract

Fagonia indica (L.) is an important medicinal plant with multitude of therapeutic potentials. Such application has been attributed to the presence of various pharmacological important phytochemicals. However, the inadequate biosynthesis of such metabolites in intact plants has hampered scalable production. Thus, herein, we have established an in vitro based elicitation strategy to enhance such metabolites in callus culture of F. indica. Cultures were exposed to various doses of UV radiation (UV-C) and grown in different photoperiod regimes and their impact was evaluated on biomass accumulation, biosynthesis of phytochemicals along antioxidant expression. Cultures grown under photoperiod (16L/8D h) after exposure to UV-C (5.4 kJ/m2) accumulated optimal biomass (438.3 g/L FW; 16.4 g/L DW), phenolics contents (TPC: 11.8 μgGAE/mg) and flavonoids contents (TFC: 4.05 μgQE/mg). Similarly, HPLC quantification revealed that total production (6.967 μg/mg DW) of phytochemicals wherein kaempferol (1.377 μg/mg DW), apigenin (1.057 μg/mg DW), myricetin (1.022 μg/mg DW) and isorhamnetin (1.022 μg/mg DW) were recorded highly accumulated compounds in cultures at UV-C (5.4 kJ/m2) dose than other UV-C radiations and light regimes.. The antioxidants activities examined as DPPH (92.8%), FRAP (182.3 µM TEAC) and ABTS (489.1 µM TEAC) were also recorded highly expressed by cultures under photoperiod after treatment with UV-C dose 5.4 kJ/m2. Moreover, same cultures also expressed maximum % inhibition towards phospholipase A2 (sPLA2: 35.8%), lipoxygenase (15-LOX: 43.3%) and cyclooxygenases (COX-1: 55.3% and COX-2: 39.9%) with 1.0-, 1.3-, 1.3- and 2.8-fold increased levels as compared with control, respectively. Hence, findings suggest that light and UV can synergistically improve the metabolism of F. indica and could be used to produce such valuable metabolites on commercial scale.

Comparative Effects of Different Light Sources on the Production of Key Secondary Metabolites in Plants In Vitro Cultures

“…UV-B photons are perhaps the most intense wave that hits the surface of the earth, and even tiny changes in their quantity can have a huge impact on vital processes and properties at all scales, from species to ecosystems [26]. In addition to the rest of the UV groups, UV-C radiation has also proved to be the most effective in stimulating the production of plant secondary metabolites such as phenolics, alkaloids, or flavonoids [27][28][29] (Table 1).…”

Copper oxide (CuO) and manganese oxide (MnO) nanoparticles induced biomass accumulation, antioxidants biosynthesis and abiotic elicitation of bioactive compounds in callus cultures of Ocimum basilicum (Thai basil)

“…The most prevalent compounds in O. basilicum are rosmarinic acid, chicoric acid, caffeic acid, euginol and anthocyanins that have momentous commercial value and health attributes [7]. Different metabolic aspects involved in plant growth and protection from harmful agents are also influenced by these bioactive compounds thoroughly distributed in plant [8].…”

“…Plant in vitro culture technology is a better feasible alternative approach that provides smooth, eco-friendly and cost efficient extraction methodologies over chemical synthesis or direct extraction from wild plants [8,12]. For instance, several alterations or modifications to such systems made to further enhance the biosynthesis of compounds because an output capacity of such systems is intrinsically limited [13].…”

“…Elements of different nature are used as stimulating agents that elicit key metabolite biosynthesis in in vitro cultures. The phytochemicals production is elicited or initiated by inducing defense system activated as stress response in plants [8]. Mechanistically, the generation of reactive oxygen species is increased in stress conditions and the plant's antioxidant system gets switched via enzymatic and nonenzymatic pathways [14].…”

Ingestion of Okinawa Island Vegetables Increases IgA Levels and Prevents the Spread of Influenza RNA Viruses

“…The antioxidant activity of the phytochemicals in Okinawan vegetables, which grow under exposure to ultraviolet light stronger than that in other prefectures in our country, is high [ 4 ]. The UV treatments under different photoperiod regimes effectively raise flavonoids biosynthesis among all phenolic compounds and may upregulate chalcone synthase and flavonol synthase for flavonoid production [ 5 ]. The dietary flavonoids, especially their glycosides, are the most vital phytochemicals in the diet and are of great general interest due to their diverse bioactivity.…”