Elevated CO2 induces a global metabolic change in basil (Ocimum basilicum L.) and peppermint (Mentha piperita L.) and improves their biological activity

Abstract

Many studies have discussed the influence of elevated carbon dioxide (eCO) on modeling and crop plants. However, much less effort has been dedicated to herbal plants. In this study, a robust monitoring for the levels of 94 primary and secondary metabolites and minerals in two medicinal herbs, basil (Ocimum basilicum L.) and peppermint (Mentha piperita L.), grwon under both ambient (aCO, 360 ppm) and eCO (620 ppm) was performed. We also assessed how the changes in herbal tissue chemistry affected their biological activity. Elevated CO significantly increased herbal biomass, improved the rates of photosynthesis and dark respiration, and altered the tissue chemistry. Principal Component Analysis of the full data set revealed that eCO induced a global change in the metabolomes of the two plants. Moreover, Hierarchical Clustering Analyses showed quantitative differences in the metabolic profiles of the two plants and in their responsiveness to eCO. Out of 94 metabolites, 38 and 31 significantly increased in basil and peppermint, respectively, as affected by eCO. Regardless of the plant species, the levels of non-structural carbohydrates, fumarate, glutamine, glutathione, ascorbate, phylloquinone (vitamin K1), anthocyanins and a majority of flavonoids and minerals were significantly improved by eCO. However, some metabolites tended to show species specificity. Interestingly, eCO caused enhancement in antioxidant, antiprotozoal, anti-bacterial and anticancer (against urinary bladder carcinoma; T24P) activities in both plants, which was consequent with improvement in the levels of antioxidant metabolites such as glutathione, ascorbate and flavonoids. Therefore, this study suggests that the metabolic changes triggered by eCO in the target herbal plants improved their biological activities.

Interactive Impact of Arbuscular Mycorrhizal Fungi and Elevated CO2 on Growth and Functional Food Value of Thymus vulgare

“…It has been known that the photosynthetic rate, and consequently biomass production, could be improved under the effect of AMF inoculation, as a result of the expected increased nutrients uptake [ 36 ], and also under eCO 2 atmosphere due to the enhancement of the carboxylation reaction of rubisco [ 37 ]. Supporting this hypothesis, the current results revealed that eCO 2 and AMF independently, and to more extent in combination, promoted photosynthetic rate and biomass production in T. vulgare ( Figure 1 ).…”

“…In this regard, sugars and organic acids are related to taste and flavor [ 47 ], essential amino acids are involved in some biological processes, such as protein synthesis [ 48 ] and a lower saturated/unsaturated fatty acids (SFA/USFA) ratio is linked to cardio-protective effects [ 49 ]. It has been reported that the higher the CO2 levels, the higher the rate of photosynthetic activity, which is linked to the enhancement of the carboxylation reaction of rubisco, the enzyme responsible for CO 2 fixation [ 37 ]. As a consequence of photosynthesis improvement, sugars could be accumulated and also broken down via dark respiration, resulting in production of the precursors necessary for synthesis of different classes of primary and secondary metabolites [ 50 ].…”

“…It was found that AMF could affect secondary metabolites through improved photosynthesis and mineral content of the host plants, activation of pathways involved in synthesis of secondary metabolites, or higher expression of some genes related to secondary metabolism [ 68 ]. On the other hand, the eCO 2 -induced changes in plant secondary metabolism have been attributed to either excess amount of non-structural carbohydrates, resulting in an increment in carbon-based secondary metabolites [ 9 , 37 , 51 ].…”

Laser Light Treatment of Seeds for Improving the Biomass Photosynthesis, Chemical Composition and Biological Activities of Lemongrass Sprouts

“…We used the DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate), oxygen radical absorbance (ORAC) and ferric reducing antioxidant power (FRAP) assays to measure total antioxidant power in Cymbopogon proximus seeds, as described before [32]. Briefly, 0.25 g of the seed powder was extracted in ethanol (80%) and centrifuged at 14,000 rpm for 30 min.…”

Actinomycetes Enrich Soil Rhizosphere and Improve Seed Quality as well as Productivity of Legumes by Boosting Nitrogen Availability and Metabolism

“…It was detected by HPLC using a fluorescence detector (excitation, 243 nm; emission, 430 nm). The β-cryptoxanthin contents were extracted in acetone and analyzed by a reversed phase HPLC conducted with a diode array detector [39]. Thiamine was extracted in 0.1 N HCl after incubation of 30 min in a water bath.…”