In vitro enhanced accumulation of polyphenols during somatic embryogenesis in Plantago ovata Forsk

ABSTRACT Plantago ovata Forsk (common isabgul) is much known for its medicinal importance. It is a potential source of bioactive compounds like polyphenols which serve as natural antioxidant having an ability to quench cytotoxic free radicals that are preventive to many diseases. In present investigation, the accumulation of polyphenolic compounds was studied during in vitro somatic embryogenesis in Plantago ovata. Calli of three different developmental stages during somatic embryogenesis were selected for this purpose and total polyphenol content was determined spectrophotometrically using FolinCiocalteu reagent. The embryogenic calli were found to contain highest level of polyphenolics. Further, the effect of exogenous additives like casein hydrolysate and coconut water on the accumulation of total polyphenol was also included into the study. 42 days old calli were treated with different concentrations of casein hydrolysate (1 gL -1 , 2 gL -1 , 3 gL -1 ) and coconut water (5%, 10%, 15%) and used for total polyphenol content determination. 2 gL -1 casein hydrolysate and 5% coconut water produced the best result. So the study shows a greater promise in advancing the use of Plantago ovata for producing phenolic compounds in a larger scale

Selenium biofortification improves bioactive composition and antioxidant status in Plantago ovata Forsk., a medicinal plant

Abstract Background Selenium (Se) is an essential micronutrient for humans, but its deficiency as well as toxicity affects large number of people worldwide. Plantago ovata, a commercially important medicinal plant, is mainly cultivated in western regions of India, where elevated levels of Se have been found in soil. Thus, we evaluated the potential of Se biofortification in P. ovata via phytoremediation and its effect on the bioactive composition. Results The results showed a significant alteration in various morphological and physiological parameters in a dose-dependent manner. The 10 µM Se dose improved seedling height, biomass and total chlorophyll content. There was a gradual increase in total Se content, with highest accumulation of 457.65 µg/g FW at 500 µM Se treatment. Se positively affected the antioxidative metabolism which was measured from the change in total antioxidant capacity, radical scavenging activity and Metallothionein 2 expression. Increasing levels of Se also affected the PAL activity, total polyphenol and flavonoid content. Caffeic acid, Coumaric acid and Rutin were found to be the most abundant phenolic compounds. Conclusions Low levels of selenium (below 50 µM) can successfully improve Se accumulation and elicit production of various polyphenols without hampering plant growth. Thus, Se fortification of P. ovata seedlings via phytoremediation appears to be a feasible and efficient way to enhance its nutraceutical value in dietary products

Chromium (VI) – induced stress response in the plant Plantago ovata Forsk in vitro

Abstract Background Plants experience severe physiological stress from heavy metal pollution caused by improper discarding of the industrial wastes. Hexavalent chromium [Cr (VI)] is one of the major heavy metal pollutants in India and is present particularly in some regions where Plantago ovata grows to a great extent. This study was aimed at finding the effects of Cr (VI) on P. ovata and manoeuvres of the plant to combat such heavy metal exposure in vitro. Methods Potassium dichromate was used as a source of Cr (VI) to induce the heavy metal stress. Range of Cr (VI) sublethal doses [0 mM (control), 0.1 mM, 0.3 mM, 0.5 mM, 1 mM, 1.5 mM and1.8 mM] was used to observe its effect on the plant. The seeds of the plant were grown on sucrose-agar media with different concentrations of potassium dichromate, and ten-day old seedlings were then harvested and examined. Results The germination rate reduced below 50% at 1.9 mM Cr (VI) concentration and thus, 0 mM–1.8 mM concentration ranges were found to be suitable for sublethal dose. Morphological changes namely, reduction of the shoot-root length and multiple root development were caused by Cr (VI) in a dose-dependent manner. The plant showed elevated responses against Cr (VI), up to 1.5 mM (10 days treated) in terms of increasing accumulation of secondary metabolites like polyphenols, chlorophyll content (chlorophyll a, b and total chlorophyll), carotenoids and total antioxidant activity. DPPH radical scavenging activity along with malondialdehyde (MDA) content was not significantly elevated with the increase in Cr (VI) concentration indicating that the lipid peroxidation rate within the tissue was low. Phenylalanine ammonia lyase (PAL) and polyphenol oxidase (PPO) gene expressions were upregulated by 1 mM Cr (VI) concentration, which decreased at higher concentrations. The atomic absorption spectroscopy analysis also showed significant accumulation of Cr (VI) in the shoot and root with an increase in the potassium dichromate concentration. Conclusion Cr (VI) reduced the shoot-root length and seed germination in a dose-dependent manner. The plant system tried to combat the Cr (VI) stress by upregulating the stress response genes in the phenylpropanoid pathway along with an increase in polyphenol and antioxidant contents, which were evident from the lowering of lipid peroxidation rate and increase in PAL and PPO gene expressions

<i>In vitro</i> regeneration of <i>Hypericum perforatum</i> L. using thidiazuron and analysis of genetic stability of regenerants

92-98In the present study, in vitro regeneration method for Hypericum perforatum L. using different plant growth regulators has been developed. Callus was induced from hypocotyl explants on MS medium using 0.5 mg L-1 2,4-dichlorophenoxyacetic acid (2,4-D) and 1 mg L-1 kinetin (Kn). Shoots were developed on the medium containing 1 mg L-1 thidiazuron and rooting was achieved with 2 mg L-1 indoleacetic acid (IAA). Random amplified polymorphic DNA (RAPD) and restriction fragment length polymorphism (RFLP) were used to assess the genetic stability of the regenerated plants. Among a large number of regenerated plantlets, 10 plants were randomly selected for molecular analysis. 15 RAPD primers generated monomorphic banding pattern among the mother and regenerated plants. PCR-RFLP profiles of nuclear ribosomal internal transcribed spacer (nrITS) region using EcoRV, ClaI and HpaII also did not show any variation in banding pattern. The entire ITS region of the mother plant, and a randomly selected regenerated plant, when cloned and sequenced showed query coverage of 99% when analyzed through CLUSTAL W. These molecular analyses showed that the regenerated plants produced were similar to the mother plant both in phenotypic and genotypic characters