Defense potential of secondary metabolites in medicinal plants under UV-B stress

The Role of Carnosic Acid in the UV-B Stress Resistance Signalling Pathway in Arabidopsis thaliana

Carnosic acid (CA) is recognized as an antioxidant that confers protection to plants against various forms of oxidative stress, including UV-B stress. However, limited research has been conducted to elucidate the molecular mechanisms underlying its defence against UV-B stress. In this study, we demonstrated that CA exhibits more efficacy compared to other antioxidants in UV-B resistance. Moreover, CA was found to enhance the accumulation of secondary metabolites in Arabidopsis leaves. Through the analysis of differentially expressed genes in response to UV-B stress with or without CA treatment, we uncovered that the exogenous application of CA effectively activates the flavonoid biosynthesis pathway in Arabidopsis to improve resistance of Arabidopsis to UV-B stress.

Light quality regulates growth and flavonoid content in a widespread forest understorey medicinal species Scutellaria Baicalensis Georgi

Introduction

Introduction: Light is not only essential for plant photosynthesis and growth, but also acts as a signal to regulate its secondary metabolism. Despite the influence of light quality on the yield and flavonoid compounds in commercial crops is well-documented, its role in regulating wild understorey species, particularly medicine plants whose flavonoid biosynthesis driven by multiple spectral regions of canopy sunlight, is less understood.

Methods

To address it, we conducted a light-quality manipulation experiment on Scutellaria baicalensis Georgi, a widespread understorey medicinal species, with light-emitting diodes (LED). This study included eight treatments: UV-A (UV-A radiation), CK (control group), Green (monochromatic green light), and different combinations of blue and red light (R0B4: monochromatic blue light; R1B3: 25% Red+75% Blue light; R1B1: 50% Red+50% Blue light; R3B1: 75% Red+25% Blue light; R4B0: monochromatic red light).

Results

Our results showed that light quality significantly drove morphology, biomass accumulation, and flavonoids biosynthesis in S. baicalensis. R0B4 treatment promoted growth and flavonoids accumulation, including baicalin, and wogonoside concentrations. In contrast, UV-A radiation and green light negatively impacted these parameters compared to CK treatment. Interestingly, plant biomass and flavonoid concentrations were lower in R1B3, R1B1 and R3B1 treatments compared to monochromatic blue or red light.

Discussion

Our study found that red light may antagonize blue light-stimulated growth and flavonoids accumulation, indicating a complex crosstalk between photoreceptors. These findings highlight the importance of blue light for optimizing the yield and quality of S. baicalensis in the understorey cultivation. It provides practice suggestion for the efficient management and sustainable cultivation of understorey medicinal plants.

Para rubber seed oil and its fatty acids alleviate photoaging and maintain cell homeostasis

OBJECTIVE

Para rubber seed oil was indicated for skin dullness and hair loss in regard to its cutaneous beneficial fatty acids. Nonetheless, the oil's potency against photoaging remains unexplored. We proposed that para rubber seed oil could alleviate photoaging.

METHODS

Para rubber seed oil was investigated in cocultures of human HaCaT cells and dermal fibroblasts (HDF). Photoaging protectant efficiency was monitored in terms of IL-6 and IL-8 as well as MMP-1 (collagenase) and MMP-9 (gelatinase) in a comparison with its fatty acid components.

RESULTS

Para rubber seed oil standardized in fatty acids was indicated as the promising plant oil for photoaging treatment. Its photoprotection mechanism was demonstrated in the coculture system of keratinocyte and fibroblast cells for the first time. Where the oil and its fatty acid constituents (100 μg/mL) were indicated to be safe and efficiently protect the cocultures against UV damage. The oil significantly (p < 0.001) suppressed UV-induced IL-6, IL-8, MMP-1 and MMP-9 secretions. The revealed photoprotection proficiency was abided by its fatty acids, particularly the unsaturated C18 ones.

CONCLUSION

The oil was indicated on its potential to maintain skin homeostasis and would alleviate senescence ageing in regard to its photoprotection abilities exhibited. Para rubber seed oil is warranted as a new generation of photoaging protectant agent with the profiled safety and efficacy demonstrated in the epidermal coculture system. The findings encourage the development of innovative anti-ageing products containing the oil, which is categorizable as a sustainable specialty material for photoaging treatment.

Ultraviolet-B Radiation Stimulates Flavonoid Biosynthesis and Antioxidant Systems in Buckwheat Sprouts

Abiotic stress not only elevates the synthesis of secondary metabolites in plant sprouts but also boosts their antioxidant capacity. In this study, the mechanisms of flavonoid biosynthesis and antioxidant systems in buckwheat sprouts exposed to ultraviolet-B (UV-B) radiation were investigated. The findings revealed that UV-B treatment significantly increased flavonoid content in buckwheat sprouts, with 3-day-old sprouts exhibiting a flavonoid content 1.73 times greater than that of the control treatment. UV-B radiation significantly increased the activities of key enzymes involved in flavonoid biosynthesis (phenylalanine ammonia-lyase, 4-coumarate-CoA ligase, cinnamate 4-hydroxylase, and chalcone synthase) and the relative expression levels of the corresponding genes. Although UV-B radiation caused damage to the cell membranes of buckwheat sprouts, promoting increases in hydrogen peroxide and malondialdehyde content and inhibiting the growth of sprouts, importantly, UV-B radiation also significantly increased the activities of catalase, peroxidase, and superoxide dismutase as well as the relative expression levels of the corresponding genes, thus enhancing the antioxidant system of buckwheat sprouts. This enhancement was corroborated by a notable increase in ABTS, DPPH, and FRAP radical scavenging activities in 3-day-old sprouts subjected to UV-B radiation. Additionally, UV-B radiation significantly increased chlorophyll a and chlorophyll b contents in sprouts. These results suggest that UV-B radiation is advantageous for cultivating buckwheat sprouts with increased flavonoid content and enhanced antioxidant capacity.

Boosting Health Benefits in Vegetables: A Novel Ultraviolet B (UVB) Device for Rapid At-Home Enhancement of Phytochemicals and Bioactivity

The consumption of vegetables is essential for reducing the risk of noncommunicable diseases, yet global intake falls short of recommended levels. Enhancing the nutraceutical content of vegetables through postharvest abiotic stress, such as ultraviolet B (UVB) radiation, offers a promising solution to increase health benefits. This study developed a user-friendly, at-home UVB device designed to increase the phytochemical content in common vegetables like carrots, lettuce, and broccoli. The device applies UVB radiation (305-315 nm) to fresh-cut vegetables, optimizing exposure time and intensity to maximize nutraceutical enrichment. The results demonstrated that UVB exposure increased the phenolic content by 44% in carrots, 58% in broccoli, and 10% in lettuce, with chlorogenic acid levels rising by 367% in lettuce, 547% in broccoli, and 43% in carrots after 48 h of storage. UVB treatment also enhanced antioxidant activity by up to 41% in broccoli and anti-inflammatory potential by 22% in carrots. In terms of gene expression, UVB treatment upregulated UCP-1 expression by 555% in carrots, enhanced thermogenesis, and increased SIRT-1 and ATGL expression by over 200%, promoting lipid metabolism. This process provides a convenient and efficient method for consumers to boost the health benefits of their vegetables. The study concludes that UVB-induced abiotic stress is an effective strategy to improve vegetable nutritional quality, offering a novel approach to increasing bioactive compound intake and aiding in the prevention of diet-related diseases.

UV-B irradiation promotes anthocyanin biosynthesis in the leaves of Lycium ruthenicum Murray

Anthocyanins are the most valuable pigments in Lycium ruthenicum Murray (L. ruthenicum). Although ultraviolet-B (UV-B) irradiation is a key environmental factor influencing anthocyanin biosynthesis in L. ruthenicum, the deep molecular mechanism remains unclear. Herein, we examined the changes in the total anthocyanin content and transcriptomic characteristics of L. ruthenicum leaves following UV-B irradiation treatment. The results showed a twofold increase in anthocyanin content in the leaves of L. ruthenicum after the treatment. The transcriptome analysis showed that the expression of 24 structural genes identified in the anthocyanin synthesis pathway was up-regulated. In particular, F3'H (Unigene0009145) and C4H (Unigene0046607) exhibit notable up-regulation, suggesting their potential roles in anthocyanin synthesis. Protein interaction network results revealed that MYB1 (Unigene0047706) had the highest connectivity, followed by bHLH (Unigene0014085). Additionally, UVR8 (Unigene0067978) and COP1 (Unigene0008780) were found to be highly involved in UV-B signal transduction. These findings provide new insights into the genetic and biochemical mechanisms that regulate anthocyanin production, and could guide agricultural practices to reduce environmental impacts and improve crop yield and quality.

Understanding mechanistic variability in physiological and biochemical responses of pea cultivars (Pisum sativum L.) to ozone exposure

Increasing concentration of ground level O3 and its negative impacts on agricultural output is well documented, however, the response of leguminous crop plants is still sparsely cited. Given their nutritional richness, legume seeds are widely esteemed as a crucial dietary staple worldwide, prized for their abundance of oil, protein, dietary fiber, and low-fat characteristics. Termed as the "poor man's meat" due to their high-quality protein, they hold immense economic value. Acknowledging the significance of legumes, a field experiment was conducted to understand the physiological and antioxidant responses, stomatal characteristics, and yield response in three cultivars of Pisum sativum L. (K Agaiti, K Uday and K Damini), exposed to elevated ozone (O3). In the present study, Pisum sativum cultivars were subjected to ambient (control) and elevated (+15 ppb) concentrations of O3, using separate sets of OTCs. Elevated O3 stimulated the activity of the enzymes of Halliwell Asada pathway, which were responsible for the differential response of the three experimental cultivars. While K Agaiti and K Uday focused on upregulating their antioxidant defense, K Damini followed the strategy of biomass allocation. Test weight showed that K Damini was most efficient in succoring the yield losses under elevated O3. Under elevated O3, test weight reduced by 8.91%, 7.52%, and 5.1%, respectively, in K Agaiti, followed by K Uday and K Damini, rendering K Agaiti most sensitive to O3 stress. The present study not only helps us to elucidate the O3 sensitivity of the selected experimental cultivars, it also helps us in screening O3 tolerant cultivars for future agricultural practices.

Photoprotective effect of topical treatment with Lopezia racemosa extract against deleterious UVB irradiation effects in the skin of hairless mice

Lopezia racemosa is known as a "mosquito flower or perlilla." It is commonly found in corn crops. In traditional Mexican medicine, this plant is used to treat stomach cancer and urinary tract infections. Likewise, compounds and extracts isolated from plants have shown cytotoxic and anti-inflammatory effects. The objective of this study was to evaluate the photochemoprotective effect of topical treatment with the methanolic extract of L. racemosa (MELR) as a photochemoprotective agent against the harmful effects of UV irradiation (UVR) on a bacterial model and hairless mice. The MELR components were separated and analyzed via HPLC-UV-ESI-MS. Antioxidant activity was evaluated by the ability of MERL to scavenge DPPH and ABTS free radicals and by its FRAP capacity. The toxicity of MELR was evaluated in keratinocyte cultures. The photoprotective capacity of MELR was assessed through challenge experiments using models with bacteria and hairless CD1 et/et mice; cytokines related to the damage caused by UVR were also measured. In the methanolic extract of L. racemosa, five metabolites were detected and identified: two isomers of quercetin 6-C glycoside, orientin, quercetin 3-(6″-acetylglycoside) and quercetin 3-(6″-galloylglycoside) 7-(2,3-dihydroxytetrahydro-2H-pyran-4-yl acetate). MELR exhibited DPPH and ABTS radical scavenging properties, in addition to Fe ion reducing activity. MELR showed a photoprotective effect against UVB radiation-induced death in Escherichia coli bacteria. At the histological level, topical treatment of CD-1 et/et mice with MERL reduced the damage caused by UVR. Quantification of interleukins in the blood of mice revealed that the expression of IL-12 was greater in the control group treated with ultraviolet radiation than in the group protected with MELR. The methanolic extract of L. racemosa has photochemoprotective properties.

NtMYB27 acts downstream of NtBES1 to modulate flavonoids accumulation in response to UV-B radiation in tobacco

UV-B radiation can induce the accumulation of many secondary metabolites, including flavonoids, in plants to protect them from oxidative damage. BRI1-EMS-SUPPRESSOR1 (BES1) has been shown to mediate the biosynthesis of flavonoids in response to UV-B. However, the detailed mechanism by which it acts still needs to be further elucidated. Here, we revealed that UV-B significantly inhibited the transcription of multiple transcription factor genes in tobacco, including NtMYB27, which was subsequently shown to be a repressor of flavonoids synthesis in tobacco. We further demonstrated that NtBES1 directly binds to the E-box motifs present in the promoter of NtMYB27 to mediate its transcriptional repression upon UV-B exposure. The UV-B-repressed NtMYB27 could bind to the ACCT-containing element (ACE) in the promoters of Nt4CL and NtCHS and served as a modulator that promoted the biosynthesis of lignin and chlorogenic acid (CGA) but inhibited the accumulation of flavonoids in tobacco. The expression of NtMYB27 was also significantly repressed by heat stress, suggesting its putative roles in regulating heat-induced flavonoids accumulation. Taken together, our results revealed the role of NtBES1 and NtMYB27 in regulating the synthesis of flavonoids during the plant response to UV-B radiation in tobacco.

Recent advances in Scutellariae radix: A comprehensive review on ethnobotanical uses, processing, phytochemistry, pharmacological effects, quality control and influence factors of biosynthesis

Background

Scutellariae radix (SR) is the dried root of Scutellaria baicalensis Georgi. It has a long history of ethnic medicinal use, traditionally recognized for its efficacy in clearing heat， drying dampness, eliminating fire， removing toxins , stopping bleeding and tranquilizing fetus to prevent miscarriage. Clinically, it is used to treat cold, fever, migraine, hand-foot-and-mouth diseases, liver cancer and inflammatory diseases.

Purpose

The review aims to provide a comprehensive reference on the ethnobotanical uses, processing, phytochemistry, pharmacological effect, quality control and influence factors of biosynthesis for a deeper understanding of SR.

Results and conclusion

A total of 210 isolated components have been reported in the literature, including flavonoids and their glycosides, phenylpropanoids, phenylethanoid glycosides, phenolic acids, volatile components, polysaccharides and others. The extract of SR and its main flavonoids such as baicalin, baicalein, wogonin, wogonoside, and scutellarin showed antioxidant, anti-inflammatory, anti-tumor, antiviral, hepatoprotective, and neuroprotective effects. However, further studies are required to elucidate its mechanisms of action and clinical applications. The pharmacodynamic evaluation based on traditional efficacy should be conducted. Although various analytical methods have been established for the quality control of SR, there are gaps in the research regarding efficacy-related quality markers and the development of quality control standards for its processed products. The regulatory mechanisms of flavonoids biosynthesis remain to be explored while the influence of environmental and transcription factors on the biosynthesis have been studied. In conclusion, SR is a promising herbal medicine with significant potential for future development.

Dissecting the genetic basis of UV-B responsive metabolites in rice

BACKGROUND

UV-B, an important environmental factor, has been shown to affect the yield and quality of rice (Oryza sativa) worldwide. However, the molecular mechanisms underlying the response to UV-B stress remain elusive in rice.

RESULTS

We perform comprehensive metabolic profiling of leaves from 160 diverse rice accessions under UV-B and normal light conditions using a widely targeted metabolomics approach. Our results reveal substantial differences in metabolite accumulation between the two major rice subspecies indica and japonica, especially after UV-B treatment, implying the possible role and mechanism of metabolome changes in subspecies differentiation and the stress response. We next conduct a transcriptome analysis from four representative rice varieties under UV-B stress, revealing genes from amino acid and flavonoid pathways involved in the UV-B response. We further perform a metabolite-based genome-wide association study (mGWAS), which reveals 3307 distinct loci under UV-B stress. Identification and functional validation of candidate genes show that OsMYB44 regulates tryptamine accumulation to mediate UV-B tolerance, while OsUVR8 interacts with OsMYB110 to promote flavonoid accumulation and UV-B tolerance in a coordinated manner. Additionally, haplotype analysis suggests that natural variation of OsUVR8groupA contributes to UV-B resistance in rice.

CONCLUSIONS

Our study reveals the complex biochemical and genetic foundations that govern the metabolite dynamics underlying the response, tolerance, and adaptive strategies of rice to UV-B stress. These findings provide new insights into the biochemical and genetic basis of the metabolome underlying the crop response, tolerance, and adaptation to UV-B stress.

Effects of UV-B and UV-C Spectrum Supplementation on the Antioxidant Properties and Photosynthetic Activity of Lettuce Cultivars

Indoor farming systems enable plant production in precisely controlled environments. However, implementing stable growth conditions and the absence of stress stimulants can weaken plants' defense responses and limit the accumulation of bioactive, health-beneficial phytochemicals. A potential solution is the controlled application of stressors, such as supplemental ultraviolet (UV) light. To this end, we analyzed the efficiency of short-term pre-harvest supplementation of the red-green-blue (RGB, LED) spectrum with ultraviolet B (UV-B) or C (UV-C) light to boost phytochemical synthesis. Additionally, given the biological harm of UV radiation due to high-energy photons, we monitored plants' photosynthetic activity during treatment and their morphology as well as sensory attributes after the treatment. Our analyses showed that UV-B radiation did not negatively impact photosynthetic activity while significantly increasing the overall antioxidant potential of lettuce through enhanced levels of secondary metabolites (total phenolics, flavonoids, anthocyanins), carotenoids, and ascorbic acid. On the contrary, UV-C radiation-induced anthocyanin accumulation in the green leaf cultivar significantly harmed the photosynthetic apparatus and limited plant growth. Taken together, we showed that short-term UV-B light supplementation is an efficient method for lettuce biofortification with healthy phytochemicals, while UV-C treatment is not recommended due to the negative impact on the quality (morphology, sensory properties) of the obtained leafy products. These results are crucial for understanding the potential of UV light supplementation for producing functional plants.

Comprehensive Modulation of Secondary Metabolites in Terpenoid-Accumulating Mentha spicata L. via UV Radiation

In plants, secondary metabolites change in response to environmental conditions. These changes co-regulate resilience to stressful environmental conditions, plant growth and development, and interactions between plants and the wider ecosystem, while also affecting soil carbon storage and atmospheric and climatic conditions. The objective of this study was to determine the association between UV exposure and the contents of key metabolites, including amino acids, phenolics, flavonoids, terpenoids, carotenoids, tocopherols, and phytosterols. Mentha spicata plantlets were grown in tissue culture boxes for 30 days and then exposed to a low dose of broadband UV-B (291-315 nm; 2.8 kJm-2 biologically effective UV) enriched light for eight days. Metabolite contents were quantified either immediately after the final UV exposure, or after seven days of recovery under photosynthetically active radiation. It was found that UV promoted the production of flavonoids (1.8-fold) ahead of phenolic acids (unchanged). Furthermore, the majority of monoterpenes and sesquiterpenes, constituents of valuable mint essential oil, were significantly increased through UV treatment (up to 90-fold for α-linalool). In contrast, the contents of carotenoids and tocopherols did not increase following UV exposure. A comparison between plants sampled immediately after UV exposure and after seven days of recovery showed that there was an overall increase in the content of carotenoids, mono- and sesquiterpenes, phenolics, and amino acids following recovery, while the contents of sterols and tocopherols decreased. These UV-induced changes in metabolite profile may have important consequences for agriculture, ecology, and even the global climate, and they also provide an exciting opportunity to enhance crop value, facilitating the development of improved products with higher levels of essential oils and added benefits of enhanced flavour, colour, and bioactive content.

GBF family member PfGBF3 and NAC family member PfNAC2 regulate rosmarinic acid biosynthesis under high light

Rosmarinic acid (RA) is an important medicinal metabolite and a potent food antioxidant. We discovered that exposure to high light intensifies the accumulation of RA in the leaves of perilla (Perilla frutescens (L.) Britt). However, the molecular mechanism underlying RA synthesis in response to high light stress remains poorly understood. To address this knowledge gap, we conducted a comprehensive analysis employing transcriptomic sequencing, transcriptional activation, and genetic transformation techniques. High light treatment for 1 and 48 h resulted in the upregulation of 592 and 1,060 genes, respectively. Among these genes, three structural genes and 93 transcription factors exhibited co-expression. Notably, NAC family member PfNAC2, GBF family member PfGBF3, and cinnamate-4-hydroxylase gene PfC4H demonstrated significant co-expression and upregulation under high light stress. Transcriptional activation analysis revealed that PfGBF3 binds to and activates the PfNAC2 promoter. Additionally, both PfNAC2 and PfGBF3 bind to the PfC4H promoter, thereby positively regulating PfC4H expression. Transient overexpression of PfNAC2, PfGBF3, and PfC4H, as well as stable transgenic expression of PfNAC2, led to a substantial increase in RA accumulation in perilla. Consequently, PfGBF3 acts as a photosensitive factor that positively regulates PfNAC2 and PfC4H, while PfNAC2 also regulates PfC4H to promote RA accumulation under high light stress. The elucidation of the regulatory mechanism governing RA accumulation in perilla under high light conditions provides a foundation for developing a high-yield RA system and a model to understand light-induced metabolic accumulation.

Plant hormones and phenolic acids response to UV-B stress in Rhododendron chrysanthum pall

Our study aims to identify the mechanisms involved in regulating the response of Rhodoendron Chrysanthum Pall. (R. chrysanthum) leaves to UV-B exposure; phosphorylated proteomics and metabolomics for phenolic acids and plant hormones were integrated in this study. The results showed that UV-B stress resulted in the accumulation of salicylic acid and the decrease of auxin, jasmonic acid, abscisic acid, cytokinin and gibberellin in R. chrysanthum. The phosphorylated proteins that changed in plant hormone signal transduction pathway and phenolic acid biosynthesis pathway were screened by comprehensive metabonomics and phosphorylated proteomics. In order to construct the regulatory network of R. chrysanthum leaves under UV-B stress, the relationship between plant hormones and phenolic acid compounds was analyzed. It provides a rationale for elucidating the molecular mechanisms of radiation tolerance in plants.

Ménage à trois: light, terpenoids, and quality of plants

In controlled environment agriculture (CEA), light is used to impact terpenoid production and improve plant quality. In this review we discuss various aspects of light as important regulators of terpenoid production in different plant organs. Spectral quality primarily modifies terpenoid profiles, while intensity and photoperiod influence abundances. The central regulator of light signal transduction elongated hypocotyl 5 (HY5) controls transcriptional regulation of terpenoids under UV, red (R), and blue (B) light. The larger the fraction of R and green (G) light, the more beneficial the effect on monoterpenoid and sesquiterpenoid biosynthesis, and such an effect may depend on the presence of B light. A large fraction of R light is mostly detrimental to tetraterpenoid production. We conclude that light is a promising tool to steer terpenoid production and potentially tailor the quality of plants.

Low UV radiation influenced DNA methylation, gene regulation, cell proliferation, viability, and biochemical differentiation in the cell suspension cultures of Cannabis indica

The effect of low artificial Ultraviolet (UV) on the DNA methylation remains controversial. This study addresses how differential photoperiods of UV radiation affect the biochemical and molecular behaviors of Cannabis indica cell suspension cultures. The cell suspensions were illuminated with the compact fluorescent lamps (CFL), emitting a combination of 10% UVB, 30% UVA, and the rest visible wavelengths for 0, 4, 8, and 16 h. The applied photoperiods influenced cell morphological characteristics. The 4 h photoperiod was the most effective treatment for improving biomass, growth index and cell viability percentage while these indices remained non-significant in the 16 h treatment. The methylation-sensitive amplified polymorphism (MASP) assay revealed that the UV radiation was epigenetically accompanied by DNA hypermethylation. The light-treated cells significantly displayed higher relative expression of the cannabidiolic‌ acid synthase (CBDAS) and delta9-tetrahydrocannabinolic acid synthase (THCAS) genes about 4-fold. The expression of the olivetolic acid cyclase (OAC) and olivetol synthase (OLS) genes exhibited an upward trend in response to the UV radiation. The light treatments also enhanced the proline content and protein concentration. The 4 h illumination was significantly capable of improving the cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC) concentrations, in contrast with 16 h. By increasing the illumination exposure time, the activity of the phenylalanine ammonia-lyase (PAL) enzyme linearly upregulated. The highest amounts of the phenylpropanoid derivatives were observed in the cells cultured under the radiation for 4 h. Taken collective, artificial UV radiation can induce DNA methylation modifications and impact biochemical and molecular differentiation in the cell suspensions in a photoperiod-dependent manner.

Phytochemical screening of Podocarpus lambertii Klotzch ex Endl. leaf extracts and potential antimicrobial, antioxidant and antibiofilm activity

Species of the genus Podocarpus L'Hér. ex Pers.present biological activities, such as analgesic, antioxidant, antifungal, acting in the fight against anemia, depurative and fortifying. Podocarpus lambertii Klotzch ex Endl. is a Brazilian native species popularly known as maritime pine and lacks information about its phytochemical profile and possible biological activities. The study was conducted to determine the phytochemical composition of soluble plant extracts of acetone (EA), ethyl acetate (EAE) and hexane (HE) from leaves of P. lambertii; evaluate the antimicrobial potential by the broth microdilution technique; antioxidant potential by the DPPH method, as well as to evaluate the biofilm inhibition capacity by the crystal violet assay and reduction of the yellow tetrazolium salt (MTT). Phytochemical screening detected the presence of flavonoids, triterpenoids, steroids, tannins, alkaloids and saponins. All extracts showed antimicrobial activity on the microorganisms tested, and the EA showed the best results. High free radical scavenging potential was observed only in EAE (96.35%). The antibiofilm potential was observed in the EAE extract. The results contribute to the knowledge of the species and indicate the potential of P. lambertii extracts as a source of plant bioactives for the development of new alternative strategies to control resistant microorganisms.

Analysis of Primary and Secondary Metabolites, Physical Properties, Antioxidant and Antidiabetic Activities, and Chemical Composition of Rosmarinus officinalis Essential Oils under Differential Water Stress Conditions

This study investigated the effects of varying water stress levels on Rosmarinus officinalis essential oils (EO). Three samples (S1, S2, and S3) were cultivated under different stress levels (40, 60, and 80%). Increased water stress led to changes in primary and secondary metabolites, EO contents, and physical properties. Antioxidant activity varied, with S2 exhibiting the highest IC50 value. In terms of antidiabetic activity, S2 showed robust α-amylase inhibition, while S3 displayed a commendable influence. For α-galactosidase inhibition, S3 had a moderate effect, and S2 stood out with increased efficacy. Gas chromatography-mass spectrometry analysis revealed stress-induced changes in major compounds. The study enhances the understanding of plant responses to water stress, with potential applications in antioxidant therapy and diabetes management. The findings emphasize the importance of sustainable water management for optimizing the EO quality in its various uses.

Molecular crosstalk between polyphenols and gut microbiota in cancer prevention

A growing body of evidence suggests that cancer remains a significant global health challenge, necessitating the development of novel therapeutic approaches. In recent years, the molecular crosstalk between polyphenols and gut microbiota has emerged as a promising pathway for cancer prevention. Polyphenols, abundant in many plant-based foods, possess diverse bioactive properties, including antioxidant, anti-inflammatory, and anticancer activities. The gut microbiota, a complex microbial community residing in the gastrointestinal tract, plays a crucial role in a host's health and disease risks. This review highlights cancer suppressive and oncogenic mechanisms of gut microbiota, the intricate interplay between gut microbiota modulation and polyphenol biotransformation, and the potential therapeutic implications of this interplay in cancer prevention. Furthermore, this review explores the molecular mechanisms underpinning the synergistic effects of polyphenols and the gut microbiota, such as modulation of signaling pathways and immune response and epigenetic modifications in animal and human studies. The current review also summarizes the challenges and future directions in this field, including the development of personalized approaches that consider interindividual variations in gut microbiota composition and function. Understanding the molecular crosstalk could offer new perspectives for the development of personalized cancer therapies targeting the polyphenol-gut axis. Future clinical trials are needed to validate the potential role of polyphenols and gut microbiota as innovative therapeutic strategies for cancer treatment.

Comparative study of the quality indices, antioxidant substances, and mineral elements in different forms of cabbage

BACKGROUND

As the second largest leafy vegetable, cabbage (Brassica oleracea L. var. capitata) is grown globally, and the characteristics of the different varieties, forms, and colors of cabbage may differ. In this study, five analysis methods-variance analysis, correlation analysis, cluster analysis, principal component analysis, and comprehensive ranking-were used to evaluate the quality indices (soluble protein, soluble sugar, and nitrate), antioxidant content (vitamin C, polyphenols, and flavonoids), and mineral (K, Ca, Mg, Cu, Fe, Mn, and Zn) content of 159 varieties of four forms (green spherical, green oblate, purple spherical, and green cow heart) of cabbage.

RESULTS

The results showed that there are significant differences among different forms and varieties of cabbage. Compared to the other three forms, the purple spherical cabbage had the highest flavonoid, K, Mg, Cu, Mn, and Zn content. A scatter plot of the principal component analysis showed that the purple spherical and green cow heart cabbage varieties were distributed to the same quadrant, indicating that their quality indices and mineral contents were highly consistent, while those of the green spherical and oblate varieties were irregularly distributed. Overall, the green spherical cabbage ranked first, followed by the green cow heart, green oblate, and purple spherical varieties.

CONCLUSIONS

Our results provide a theoretical basis for the cultivation and high-quality breeding of cabbage.

Abscisic Acid Affects Phenolic Acid Content to Increase Tolerance to UV-B Stress in Rhododendron chrysanthum Pall

The presence of the ozone hole increases the amount of UV radiation reaching a plant's surface, and UV-B radiation is an abiotic stress capable of affecting plant growth. Rhododendron chrysanthum Pall. (R. chrysanthum) grows in alpine regions, where strong UV-B radiation is present, and has been able to adapt to strong UV-B radiation over a long period of evolution. We investigated the response of R. chrysanthum leaves to UV-B radiation using widely targeted metabolomics and transcriptomics. Although phytohormones have been studied for many years in plant growth and development and adaptation to environmental stresses, this paper is innovative in terms of the species studied and the methods used. Using unique species and the latest research methods, this paper was able to add information to this topic for the species R. chrysanthum. We treated R. chrysanthum grown in a simulated alpine environment, with group M receiving no UV-B radiation and groups N and Q (externally applied abscisic acid treatment) receiving UV-B radiation for 2 days (8 h per day). The results of the MN group showed significant changes in phenolic acid accumulation and differential expression of genes related to phenolic acid synthesis in leaves of R. chrysanthum after UV-B radiation. We combined transcriptomics and metabolomics data to map the metabolic regulatory network of phenolic acids under UV-B stress in order to investigate the response of such secondary metabolites to stress. L-phenylalanine, L-tyrosine and phenylpyruvic acid contents in R. chrysanthum were significantly increased after UV-B radiation. Simultaneously, the levels of 3-hydroxyphenylacetic acid, 2-phenylethanol, anthranilate, 2-hydroxycinnamic acid, 3-hydroxycinnamic acid, α-hydroxycinnamic acid and 2-hydroxy-3-phenylpropanoic acid in this pathway were elevated in response to UV-B stress. In contrast, the study in the NQ group found that externally applied abscisic acid (ABA) in R. chrysanthum had greater tolerance to UV-B radiation, and phenolic acid accumulation under the influence of ABA also showed greater differences. The contents of 2-phenylethanol, 1-o-p-coumaroyl-β-d-glucose, 2-hydroxy-3-phenylpropanoic acid, 3-(4-hydroxyphenyl)-propionic acid and 3-o-feruloylquinic ac-id-o-glucoside were significantly elevated in R. chrysanthum after external application of ABA to protect against UV-B stress. Taken together, these studies of the three groups indicated that ABA can influence phenolic acid production to promote the response of R. chrysanthum to UV-B stress, which provided a theoretical reference for the study of its complex molecular regulatory mechanism.

Amino Acids Biostimulants and Protein Hydrolysates in Agricultural Sciences

The effects of different types of biostimulants on crops include improving the visual quality of the final products, stimulating the immune systems of plants, inducing the biosynthesis of plant defensive biomolecules, removing heavy metals from contaminated soil, improving crop performance, reducing leaching, improving root development and seed germination, inducing tolerance to abiotic and biotic stressors, promoting crop establishment and increasing nutrient-use efficiency. Protein hydrolysates are mixtures of polypeptides and free amino acids resulting from enzymatic and chemical hydrolysis of agro-industrial protein by-products obtained from animal or plant origins, and they are able to alleviate environmental stress effects, improve growth, and promote crop productivity. Amino acids involve various advantages such as increased yield and yield components, increased nutrient assimilation and stress tolerance, and improved yield components and quality characteristics. They are generally achieved through chemical or enzymatic protein hydrolysis, with significant capabilities to influence the synthesis and activity of some enzymes, gene expression, and redox-homeostasis. Increased yield, yield components, and crop quality; improved and regulated oxidation-reduction process, photosynthesis, and physiological activities; decreased negative effects of toxic components; and improved anti-fungal activities of plants are just some of the more important benefits of the application of phenols and phenolic biostimulants. The aim of this manuscript is to survey the impacts of amino acids, different types of protein hydrolysates, phenols, and phenolic biostimulants on different plants by presenting case studies and successful paradigms in several horticultural and agricultural crops.

Simultaneously regulating absorption capacities and antioxidant activities of four stilbene derivatives utilizing substitution effect: A theoretical and experimental study against UVB radiation

With the continued depletion of the ozone layer, the sun protection consciousness of humans has gradually enhanced. Long-term ultraviolet (UV) rays exposure will lead to skin tanning, even skin cancer in severe cases, and generate free radicals to cause skin aging. To better protect human skin against UV rays, this work explores the absorption capacities and antioxidant activities of four stilbene derivatives (EHDB, EDMB, EAPD, and HPTP) through the computational chemistry method and DPPH radical scavenging experiment. The research results indicate that their absorption spectra cover the entire UV region, and can effectively protect against UVB radiation. Moreover, three prevailing antioxidant mechanisms: hydrogen atom transfer, sequential proton loss electron transfer, and single electron transfer followed by proton transfer mechanisms, were used to evaluate their antioxidant activities in the ground state. It can be concluded that the O1H1 sites of EHDB and HPTP are the most active, and the SPLET mechanism is the most preferred for the four compounds in ethanol solvent. Furthermore, the DPPH radical scavenging experiment compensates for the theoretical calculation deficiency in the excited state, revealing that the EHDB and HPTP are the most suitable for sunscreen due to their excellent performance on antioxidant capacities, whether before or after sunlight. This work will facilitate EHDB and HPTP to be applied in sunscreen and provide a novel idea in sunscreen research.

Allelopathy and allelobiosis: efficient and economical alternatives in agroecosystems

Chemical interactions in plants often involve plant allelopathy and allelobiosis. Allelopathy is an ecological phenomenon leading to interference among organisms, while allelobiosis is the transmission of information among organisms. Crop failures and low yields caused by inappropriate management can be related to both allelopathy and allelobiosis. Therefore, research on these two phenomena and the role of chemical substances in both processes will help us to understand and upgrade agroecosystems. In this review, substances involved in allelopathy and allelobiosis in plants are summarized. The influence of environmental factors on the generation and spread of these substances is discussed, and relationships between allelopathy and allelobiosis in interspecific, intraspecific, plant-micro-organism, plant-insect, and mechanisms, are summarized. Furthermore, recent results on allelopathy and allelobiosis in agroecosystem are summarized and will provide a reference for the future application of allelopathy and allelobiosis in agroecosystem.

Investigating the ecological implications of nanomaterials: Unveiling plants' notable responses to nano-pollution

The rapid advancement of nanotechnology has led to unprecedented innovations; however, it is crucial to analyze its environmental impacts carefully. This review thoroughly examines the complex relationship between plants and nanomaterials, highlighting their significant impact on ecological sustainability and ecosystem well-being. This study investigated the response of plants to nano-pollution stress, revealing the complex regulation of defense-related genes and proteins, and highlighting the sophisticated defense mechanisms in nature. Phytohormones play a crucial role in the complex molecular communication network that regulates plant responses to exposure to nanomaterials. The interaction between plants and nano-pollution influences plants' complex defense strategies. This reveals the interconnectedness of systems of nature. Nevertheless, these findings have implications beyond the plant domain. The incorporation of hyperaccumulator plants into pollution mitigation strategies has the potential to create more environmentally sustainable urban landscapes and improve overall environmental resilience. By utilizing these exceptional plants, we can create a future in which cities serve as centers of both innovation and ecological balance. Further investigation is necessary to explore the long-term presence of nanoparticles in the environment, their ability to induce genetic changes in plants over multiple generations, and their overall impact on ecosystems. In conclusion, this review summarizes significant scientific discoveries with broad implications beyond the confines of laboratories. This highlights the importance of understanding the interactions between plants and nanomaterials within the wider scope of environmental health. By considering these insights, we initiated a path towards the responsible utilization of nanomaterials, environmentally friendly management of pollution, and interdisciplinary exploration. We have the responsibility to balance scientific advancement and environmental preservation to create a sustainable future that combines nature's wisdom with human innovation.

The recent relationship between ultraviolet-B radiation and biotic resistance in plants: a novel non-chemical strategy for managing biotic stresses

Ultraviolet-B radiation (UVB; 280-315 nm) is a significant environmental factor that alters plant development, changes interactions between species, and reduces the prevalence of pests and diseases. While UVB radiation has negative effects on plant growth and performance at higher doses, at lower and ambient doses, UVB radiation acts as a non-chemical method for managing biotic stresses by having positive effects on disease resistance and genes that protect plants from pests. Understanding the recent relationship between UVB radiation and plants' biotic stresses is crucial for the development of crops that are resistant to UVB and biotic stresses. However, little is known about the recent interactions between UVB radiation and biotic stresses in plants. This review discusses the most recent connections between UVB radiation and biotic stresses in crops, including how UVB radiation affects a plant's resistance to disease and pests. The interaction of UVB radiation with pathogens and herbivores has been the subject of the most extensive research of these. This review also discusses additional potential strategies for conferring multiple UVB-biotic stress resistance in crop plants, such as controlling growth inhibition, miRNA 396 and 398 modulations, and MAP kinase. This study provides crucial knowledge and methods for scientists looking to develop multiple resistant crops that will improve global food security.

Integrated metabolic profiling and transcriptome analysis of Lonicera japonica flowers for chlorogenic acid, luteolin and endogenous hormone syntheses

The active ingredients of many medicinal plants are the secondary metabolites associated with the growth period. Lonicera japonica Thunb. is an important traditional Chinese medicine, and the flower development stage is an important factor that influences the quality of medicinal ingredients. In this study, transcriptomics and metabolomics were performed to reveal the regulatory mechanism of secondary metabolites during flowering of L. japonica. The results showed that the content of chlorogenic acid (CGA) and luteolin gradually decreased from green bud stage (Sa) to white flower stage (Sc), especially from white flower bud stage (Sb) to Sc. Most of the genes encoding the crucial rate-limiting enzymes, including PAL, C4H, HCT, C3'H, F3'H and FNSII, were down-regulated in three comparisons. Correlation analysis identified some members of the MYB, AP2/ERF, bHLH and NAC transcription factor families that are closely related to CGA and luteolin biosynthesis. Furthermore, differentially expressed genes (DEGs) involved in hormone biosynthesis, signalling pathways and flowering process were analysed in three flower developmental stage.

Physiological and omics-based insights for underpinning the molecular regulation of secondary metabolite production in medicinal plants: UV stress resilience

Despite complex phytoconstituents, the commercial potential of medicinal plants under ultraviolet (UV) stress environment hasn't been fully comprehended. Due to sessile nature, these plants are constantly exposed to damaging radiation, which disturbs their natural physiological and biochemical processes. To combat with UV stress, plants synthesized several small organic molecules (natural products of low molecular mass like alkaloids, terpenoids, flavonoids and phenolics, etc.) known as plant secondary metabolites (PSMs) that come into play to counteract the adverse effect of stress. Plants adapted a stress response by organizing the expression of several genes, enzymes, transcription factors, and proteins involved in the synthesis of chemical substances and by making the signaling cascade (a series of chemical reactions induced by a stimulus within a biological cell) flexible to boost the defensive response. To neutralize UV exposure, secondary metabolites and their signaling network regulate cellular processes at the molecular level. Conventional breeding methods are time-consuming and difficult to reveal the molecular pattern of the stress tolerance medicinal plants. Acquiring in-depth knowledge of the molecular drivers behind the defensive mechanism of medicinal plants against UV radiation would yield advantages (economical and biological) that will bring prosperity to the burgeoning world's population. Thus, this review article emphasized the comprehensive information and clues to identify several potential genes, transcription factors (TFs), proteins, biosynthetic pathways, and biological networks which are involved in resilience mechanism under UV stress in medicinal plants of high-altitudes.

Microbial fortification of pharmacological metabolites in medicinal plants

Medicinal plants are rich in secondary metabolites with beneficial pharmacological effects. The production of plant secondary metabolites is subjected to the influences by environmental factors including the plant-associated microbiome, which is crucial to the host's fitness and survival. As a result, research interests are increasing in exploiting microbial capacities for enhancing plant production of pharmacological metabolites. A growing body of recent research provides accumulating evidence in support of developing microbe-based tools for achieving this objective. This mini review presents brief summaries of recent studies on medicinal plants that demonstrate microbe-augmented production of pharmacological terpenoids, polyphenols, and alkaloids, followed by discussions on some key questions beyond the promising observations. Explicit molecular insights into the underlying mechanisms will enhance microbial applications for metabolic fortification in medicinal plants.

Water stress and exogenous carnitine on growth and essential oil profile of Eryngium foetidum L

Water stress influences plant growth and metabolism. Carnitine, an amino acid involved in lipid metabolism, has been related to responses of plants to abiotic stresses, also modulating their metabolites. Culantro (Eryngium foetidum L.) is a perennial herb, rich in essential oils, native to Latin America, commonly used due to its culinary and medicinal properties. Here, we investigated the effect of exogenous carnitine on morphophysiology and the essential oil profile of culantro plants under water stress. For this, plants were grown under three water conditions: well-watered, drought stress, and re-watered; and sprayed with exogenous carnitine (100 µM) or water (control). Culantro growth was impaired by drought and enhanced by re-watering. Carnitine, in turn, did not reverse drought effects on growth, and impaired the growth of re-watered plants, also improving photosynthetic pigment content. Water conditions and carnitine application changed the essential oil profile of the plants. Drought and re-watering improved the production of eryngial, which was even increased with exogenous carnitine in re-watered plants. In addition, hydroquinone was only produced with the combination of re-watering and carnitine application. The application of exogenous carnitine can be a strategy to induce the production of essential oil compounds with cosmetic and pharmaceutical importance in culantro.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03757-y.

Polyphenols in Plants: Structure, Biosynthesis, Abiotic Stress Regulation, and Practical Applications (Review)

Phenolic compounds or polyphenols are among the most common compounds of secondary metabolism in plants. Their biosynthesis is characteristic of all plant cells and is carried out with the participation of the shikimate and acetate-malonate pathways. In this case, polyphenols of various structures are formed, such as phenylpropanoids, flavonoids, and various oligomeric and polymeric compounds of phenolic nature. Their number already exceeds 10,000. The diversity of phenolics affects their biological activity and functional role. Most of their representatives are characterized by interaction with reactive oxygen species, which manifests itself not only in plants but also in the human body, where they enter through food chains. Having a high biological activity, phenolic compounds are successfully used as medicines and nutritional supplements for the health of the population. The accumulation and biosynthesis of polyphenols in plants depend on many factors, including physiological-biochemical, molecular-genetic, and environmental factors. In the review, we present the latest literature data on the structure of various classes of phenolic compounds, their antioxidant activity, and their biosynthesis, including their molecular genetic aspects (genes and transfactors). Since plants grow with significant environmental changes on the planet, their response to the action of abiotic factors (light, UV radiation, temperature, and heavy metals) at the level of accumulation and composition of these secondary metabolites, as well as their metabolic regulation, is considered. Information is given about plant polyphenols as important and necessary components of functional nutrition and pharmaceutically valuable substances for the health of the population. Proposals on promising areas of research and development in the field of plant polyphenols are presented.

Investigating the efficacy of topical application of Ipomoea carnea herbal cream in preventing skin damage induced by UVB radiation in a rat model

Ultraviolet-B irradiation is a common environmental stressor that has detrimental effects on human skin. Natural sunscreens are well-known for their ability to benefit inflamed sunburn and dry skin. This study examined the effect of formulated Ipomoea carnea herbal cream on UVB-induced skin damage. We screened the bioactive compounds of I. carnea crude extract, showing significant antioxidant activity. Additionally, we evaluated the cytotoxicity, revealing that I. carnea extract has less toxicity to vero cells (IC50 98.45 μg/mL) than to A375 cells (IC50 48.95 μg/mL). Based on this, we formulated the I. carnea herbal cream (FIHC) at 50, 100 and 200 mg concentrations and evaluated its organoleptic characteristics. Then, the rats were exposed to UVB radiation (32,800 J/m2) four times/week (on alternate days) before the cream was applied topically to the dorsal skin surface. Under UVB stress without treatment, rats showed deep dermal damage. In contrast, rats treated with the FIHC exhibited significantly reduced sunburn. Moreover, the histopathological and biochemical assays were confirmed by the topical application of FIHC, which had potentially reduced the skin elasticity and maintained the imbalanced enzyme and non-enzymatic antioxidant activity. Our findings amply demonstrate that the FIHC significantly accelerated the recovery of UVB-induced lesions through antioxidant and down-regulation of skin photodamage.

UV-B promotes flavonoid biosynthesis in Ginkgo biloba by inducing the GbHY5-GbMYB1-GbFLS module

Ginkgo biloba (ginkgo) leaves have medicinal value due to their high levels of secondary metabolites, such as flavonoids. We found that the flavonoid content in ginkgo leaves increases significantly at high altitudes (Qinghai-Tibet Plateau). Considering that high UV-B radiation is among the key environmental characteristics of the Qinghai-Tibet Plateau, we carried out simulated UV-B treatments on ginkgo seedlings and found that the flavonoid content of the leaves increased significantly following the treatments. Combined with results from our previous studies, we determined that the transcription factor GbHY5 may play a key role in responses to UV-B radiation. Overexpression of GbHY5 significantly promoted the accumulation of flavonoids in both ginkgo callus and Arabidopsis thaliana. Furthermore, yeast two-hybrid and real-time quantitative PCR showed that GbHY5 promoted the expression of GbMYB1 by interacting with GbMYB1 protein. Overexpression of GbMYB1 in ginkgo callus and A. thaliana also significantly promoted flavonoid biosynthesis. GbFLS encodes a key enzyme in flavonoid biosynthesis, and its promoter has binding elements of GbHY5 and GbMYB1. A dual-luciferase reporter assay indicated that while GbHY5 and GbMYB1 activated the expression of GbFLS individually, their co-expression achieved greater activation. Our analyses reveal the molecular mechanisms by which the UV-B-induced GbHY5-GbMYB1-GbFLS module promotes flavonoid biosynthesis in ginkgo, and they provide insight into the use of UV-B radiation to enhance the flavonoid content of ginkgo leaves.

Supplementary UV-B Radiation Effects on Photosynthetic Characteristics and Important Secondary Metabolites in Eucommia ulmoides Leaves

To explore the effects of ultraviolet light supplementation on the photosynthetic characteristics and content of secondary metabolites in the leaves of Eucommia ulmoides Oliver (E. ulmoides), the effects of supplementary UV-B (sUV-B) radiation on the medicinally active components of E. ulmoides were comprehensively evaluated. In our study, we selected leaves of five-year-old E. ulmoides seedlings as experimental materials and studied the effect of supplemental ultraviolet-B (sUV-B) radiation on growth, photosynthetic parameters, photosynthetic pigments, fluorescence parameters, and secondary metabolites of E. ulmoides using multivariate analysis. The results showed that the leaf area and the number of branches increased after sUV-B radiation, which indicated that sUV-B radiation was beneficial to the growth of E. ulmoides. The contents of chlorophyll a and chlorophyll b increased by 2.25% and 4.25%, respectively; the net photosynthetic rate increased by 5.17%; the transpiration rate decreased by 35.32%; the actual photosynthetic efficiency increased by 10.64%; the content of the secondary metabolite genipin increased by 12.9%; and the content of chlorogenic acid increased by 75.03%. To identify the genes that may be related to the effects of sUV-B radiation on the growth and development of E. ulmoides leaves and important secondary metabolites, six cDNA libraries were prepared from natural sunlight radiation and sUV-B radiation in E. ulmoides leaves. Comparative analysis of both transcriptome databases revealed a total of 3698 differential expression genes (DEGs), including 1826 up-regulated and 1872 down-regulated genes. According to the KOG database, the up-regulated unigenes were mainly involved in signal transduction mechanisms [T] and cell wall/membrane biogenesis [M]. It is also involved in plant hormone signal transduction and phenylpropanoid biosynthesis metabolic pathways by the KEGG pathway, which might further affect the physiological indices and the content of chlorogenic acid, a secondary metabolite of E. ulmoides. Furthermore, 10 candidate unigenes were randomly selected to examine gene expression using qRT-PCR, and the six libraries exhibited differential expression and were identical to those obtained by sequencing. Thus, the data in this study were helpful in clarifying the reasons for leaf growth after sUV-B radiation. And it was beneficial to improve the active components and utilization rate of E. ulmoides after sUV-B radiation.

Interactive effects of changes in UV radiation and climate on terrestrial ecosystems, biogeochemical cycles, and feedbacks to the climate system

Terrestrial organisms and ecosystems are being exposed to new and rapidly changing combinations of solar UV radiation and other environmental factors because of ongoing changes in stratospheric ozone and climate. In this Quadrennial Assessment, we examine the interactive effects of changes in stratospheric ozone, UV radiation and climate on terrestrial ecosystems and biogeochemical cycles in the context of the Montreal Protocol. We specifically assess effects on terrestrial organisms, agriculture and food supply, biodiversity, ecosystem services and feedbacks to the climate system. Emphasis is placed on the role of extreme climate events in altering the exposure to UV radiation of organisms and ecosystems and the potential effects on biodiversity. We also address the responses of plants to increased temporal variability in solar UV radiation, the interactive effects of UV radiation and other climate change factors (e.g. drought, temperature) on crops, and the role of UV radiation in driving the breakdown of organic matter from dead plant material (i.e. litter) and biocides (pesticides and herbicides). Our assessment indicates that UV radiation and climate interact in various ways to affect the structure and function of terrestrial ecosystems, and that by protecting the ozone layer, the Montreal Protocol continues to play a vital role in maintaining healthy, diverse ecosystems on land that sustain life on Earth. Furthermore, the Montreal Protocol and its Kigali Amendment are mitigating some of the negative environmental consequences of climate change by limiting the emissions of greenhouse gases and protecting the carbon sequestration potential of vegetation and the terrestrial carbon pool.

Biosynthesis and the Transcriptional Regulation of Terpenoids in Tea Plants (Camellia sinensis)

Terpenes, especially volatile terpenes, are important components of tea aroma due to their unique scents. They are also widely used in the cosmetic and medical industries. In addition, terpene emission can be induced by herbivory, wounding, light, low temperature, and other stress conditions, leading to plant defense responses and plant-plant interactions. The transcriptional levels of important core genes (including HMGR, DXS, and TPS) involved in terpenoid biosynthesis are up- or downregulated by the MYB, MYC, NAC, ERF, WRKY, and bHLH transcription factors. These regulators can bind to corresponding cis-elements in the promoter regions of the corresponding genes, and some of them interact with other transcription factors to form a complex. Recently, several key terpene synthesis genes and important transcription factors involved in terpene biosynthesis have been isolated and functionally identified from tea plants. In this work, we focus on the research progress on the transcriptional regulation of terpenes in tea plants (Camellia sinensis) and thoroughly detail the biosynthesis of terpene compounds, the terpene biosynthesis-related genes, the transcription factors involved in terpene biosynthesis, and their importance. Furthermore, we review the potential strategies used in studying the specific transcriptional regulation functions of candidate transcription factors that have been discriminated to date.

Do changes in Lactuca sativa metabolic performance, induced by mycorrhizal symbionts and leaf UV-B irradiation, play a role towards tolerance to a polyphagous insect pest?

The increased ultraviolet radiation (UV) due to the altered stratospheric ozone leads to multiple plant physiological and biochemical adaptations, likely affecting their interaction with other organisms, such as pests and pathogens. Arbuscular mycorrhizal fungi (AMF) and UV-B treatment can be used as eco-friendly techniques to protect crops from pests by activating plant mechanisms of resistance. In this study, we investigated plant (Lactuca sativa) response to UV-B exposure and Funneliformis mosseae (IMA1) inoculation as well as the role of a major insect pest, Spodoptera littoralis. Lettuce plants exposed to UV-B were heavier and taller than non-irradiated ones. A considerable enrichment in phenolic, flavonoid, anthocyanin, and carotenoid contents and antioxidant capacity, along with redder and more homogenous leaf color, were also observed in UV-B-treated but not in AMF-inoculated plants. Biometric and biochemical data did not differ between AMF and non-AMF plants. AMF-inoculated plants showed hyphae, arbuscules, vesicles, and spores in their roots. AMF colonization levels were not affected by UV-B irradiation. No changes in S. littoralis-feeding behavior towards treated and untreated plants were observed, suggesting the ability of this generalist herbivore to overcome the plant chemical defenses boosted by UV-B exposure. The results of this multi-factorial study shed light on how polyphagous insect pests can cope with multiple plant physiological and biochemical adaptations following biotic and abiotic preconditioning.

Genome-Wide Analysis of Long Non-Coding RNAs Related to UV-B Radiation in the Antarctic Moss Pohlia nutans

Antarctic organisms are consistently suffering from multiple environmental pressures, especially the strong UV radiation caused by the loss of the ozone layer. The mosses and lichens dominate the vegetation of the Antarctic continent, which grow and propagate in these harsh environments. However, the molecular mechanisms and related regulatory networks of these Antarctic plants against UV-B radiation are largely unknown. Here, we used an integrated multi-omics approach to study the regulatory mechanism of long non-coding RNAs (lncRNAs) of an Antarctic moss (Pohlia nutans) in response to UV-B radiation. We identified a total of 5729 lncRNA sequences by transcriptome sequencing, including 1459 differentially expressed lncRNAs (DELs). Through functional annotation, we found that the target genes of DELs were significantly enriched in plant-pathogen interaction and the flavonoid synthesis pathway. In addition, a total of 451 metabolites were detected by metabonomic analysis, and 97 differentially change metabolites (DCMs) were found. Flavonoids account for 20% of the total significantly up-regulated metabolites. In addition, the comprehensive transcriptome and metabolome analyses revealed the co-expression pattern of DELs and DCMs of flavonoids. Our results provide insights into the regulatory network of lncRNA under UV-B radiation and the adaptation of Antarctic moss to the polar environments.

Transcriptomic, metabolomic, and ATAC-seq analysis reveal the regulatory mechanism of senescence of post-harvest tomato fruit

Several physiological changes occur during fruit storage, which include the regulation of genes, metabolisms and transcription factors. In this study, we compared 'JF308' (a normal tomato cultivar) and 'YS006' (a storable tomato cultivar) to determine the difference in accumulated metabolites, gene expression, and accessible chromatin regions through metabolome, transcriptome, and ATAC-seq analysis. A total of 1006 metabolites were identified in two cultivars. During storage time, sugars, alcohols and flavonoids were found to be more abundant in 'YS006' compared to 'JF308' on day 7, 14, and 21, respectively. Differentially expressed genes, which involved in starch and sucrose biosynthesis were observed higher in 'YS006'. 'YS006' had lower expression levels of CesA (cellulose synthase), PL (pectate lyase), EXPA (expansin) and XTH (xyglucan endoglutransglucosylase/hydrolase) than 'JF308'. The results showed that phenylpropanoid pathway, carbohydrate metabolism and cell wall metabolism play important roles in prolonging the shelf life of tomato (Solanum lycopersicum) fruit. The ATAC-seq analysis revealed that the most significantly up-regulated transcription factors during storage were TCP 2,3,4,5, and 24 in 'YS006' compared to 'JF308' on day 21. This information on the molecular regulatory mechanisms and metabolic pathways of post-harvest quality changes in tomato fruit provides a theoretical foundation for slowing post-harvest decay and loss, and has theoretical importance and application value in breeding for longer shelf life cultivars.

Effect of carbon quantum dots derived from extracts of UV-B-exposed Eclipta alba on alcohol-induced liver cirrhosis in Golden Hamster

The Eclipta alba plant is considered hepatoprotective, owing to its phytoconstituents wedelolactone. In the current study, effect of elevated ultraviolet-B (eUV-B) radiation was investigated on biochemical, phytochemical, and antioxidative enzymatic activities of E. alba (Bhringraj) plant. The UV-B exposure resulted in an increase in oxidative stress, which has caused an imbalance in phytochemical, biochemical constituents, and induced antioxidative enzymatic activities. It was observed that the UV-B exposure promoted wedelolactone yield by 23.64%. Further, the leaf extract of UV-B-exposed plants was used for the synthesis of carbon quantum dots (CQDs) using low cost, one-step hydrothermal technique and its biocompatibility was studied using in vitro MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay on HepG2 liver cell line. It revealed no toxicity in any treatment groups in comparison to the control. Both CQDs and leaf extract were orally administered to the golden hamster suffering from alcohol-induced liver cirrhosis. In the morphometric study, it was clearly observed that a combination of UV-B-exposed leaf extract and synthesized CQDs delivered the best result with maximum recovery of liver tissues. The present study reveals the positive impact of UV-B exposure on the medicinally important plant, increased yield of wedelolactone, and its enhanced hepatoprotective efficacy for the treatment of damaged liver tissues.

Ethnopharmacological Potential of Phytochemicals and Phytogenic Products against Human RNA Viral Diseases as Preventive Therapeutics

RNA viruses have been the most destructive due to their transmissibility and lack of control measures. Developments of vaccines for RNA viruses are very tough or almost impossible as viruses are highly mutable. For the last few decades, most of the epidemic and pandemic viral diseases have wreaked huge devastation with innumerable fatalities. To combat this threat to mankind, plant-derived novel antiviral products may contribute as reliable alternatives. They are assumed to be nontoxic, less hazardous, and safe compounds that have been in uses in the beginning of human civilization. In this growing COVID-19 pandemic, the present review amalgamates and depicts the role of various plant products in curing viral diseases in humans.

GC-MS Analysis of Bioactive Compounds Extracted from Plant Rhazya stricta Using Various Solvents

Worldwide, human beings have traditionally employed many folkloric herbal resources as complementary and alternative remedies, and these remedies have played a pivotal role in modern medicines for many decades, as scientists have used them to develop drugs. We studied the effects of employing solvents with varying polarity on the yields of phytochemical components extracted from the plant Rhazya stricta. We used chloroform-methanol (1:1), methanol, ethanol, diethyl ether, and ethyl acetate as extraction solvents. The results showed that the efficiencies of the solvents at extracting phytochemical compounds were in this order: chloroform-methanol < ethanol < methanol < diethyl ether < ethyl acetate extract. The chloroform-methanol extract produced the highest concentration of phenolic and flavonoid contents among the five solvents tested (13.3 mg GAE/g DM and 5.43 CE/g DM). The yields of the extracted phytochemical compounds ranged from 47.55 to 6.05%. The results revealed that the properties of the extraction solvents considerably impacted the extraction yield and the phytochemical components of the R. stricta extract. Furthermore, compared with the other solvents, the chloroform-methanol extraction led to the highest yield (47.55%) and to more phytochemical substances being extracted. The aim of this study is to investigate the phytochemical compounds extracted from R. stricta with different solvents that have different polarities.

Obtaining 2,3-Dihydrobenzofuran and 3-Epilupeol from Ageratina pichinchensis (Kunth) R.King & Ho.Rob. Cell Cultures Grown in Shake Flasks under Photoperiod and Darkness, and Its Scale-Up to an Airlift Bioreactor for Enhanced Production

Ageratina pichinchensis (Kunth) R.King & Ho.Rob. is a plant used in traditional Mexican medicine, and some biotechnological studies have shown that its calluses and cell suspension cultures can produce important anti-inflammatory compounds. In this study, we established a cell culture of A. pichinchensis in a 2 L airlift bioreactor and evaluated the production of the anti-inflammatory compounds 2,3-dihydrobenzofuran (1) and 3-epilupeol (2). The maximum biomass production (11.90 ± 2.48 g/L) was reached at 11 days of culture and cell viability was between 80% and 90%. Among kinetic parameters, the specific growth rate (µ) was 0.2216 days^-1 and doubling time (td) was 3.13 days. Gas chromatography coupled with mass spectrometry (GC-MS) analysis of extracts showed the maximum production of compound 1 (903.02 ± 41.06 µg/g extract) and compound 2 (561.63 ± 10.63 µg/g extract) at 7 and 14 days, respectively. This study stands out for the significant production of 2,3-dihydrobenzofuran and 3-epilupeol and by the significant reduction in production time compared to callus and cell suspension cultures, previously reported. To date, these compounds have not been found in the wild plant, i.e., its production has only been reported in cell cultures of A. pichinchensis. Therefore, plant cell cultured in an airlift reactor can be an alternative for the improved production of these anti-inflammatory compounds.

Individual and combined effects of chromium and ultraviolet-B radiation on defense system, ultrastructural changes, and production of secondary metabolite psoralen in a medicinal plant Psoralea corylifolia L

The present study focuses on the effects of individual and combined stress of chromium (Cr) and ultraviolet-B (UV-B) radiation on Psoralea corylifolia L. The experiment comprised four sets: (i) control, (ii) eUV-B (elevated UV-B i.e., ambient + 7.2 kJ m^-2 day^-1 UV-B), (iii) Cr (chromium; 30 mg kg^-1 soil), and (iv) Cr + eUV-B (chromium and elevated UV-B; Cr 30 mg kg^-1 and ambient + 7.2 kJ m^-2 day^-1 UV-B). The eUV-B and Cr individually and in combination showed the variable responses on ultrastructure, physiology and biomass however, the impact was more prominent under individual Cr treatment followed by Cr + eUV-B and eUV-B. Higher bioconcentration factor and the lowered translocation factor consequently led to a higher reduction in the below ground biomass and the lesser reduction in above ground biomass under Cr + eUV-B treatment as compared to individual Cr treatment. In addition, higher induction in the enzymatic (glutathione reductase, ascorbate peroxidase, superoxide dismutase, and glutathione-S-transferase) and non-enzymatic antioxidants (glutathione reduced) were found to be responsible for efficient scavenging of hydrogen peroxide and superoxide radical leading to lowered MDA content under combined treatment as compared to Cr treatment. Deposition of Cr as electron dense granules in the cytoplasm, vacuoles, and cell wall under Cr and Cr + eUV-B is contemplated as one of the cellular mechanisms of P. corylifolia against the toxicity of Cr. Psoralen increased under all treatments with a maximum increase under Cr + eUV-B treatment. Taken together our results accentuated that P. corylifolia can be grown in an area contaminated with Cr and has a higher influx of UV-B for the attainment of psoralen considering its pharmaceutical perspectives.

Metabolomic responses to the mechanical wounding of Catharanthus roseus' upper leaves

Purpose

Plant secondary metabolites are used to treat various human diseases. However, it is difficult to produce a large number of specific metabolites, which largely limits their medicinal applications. Many methods, such as drought and nutrient application, have been used to induce the biosynthetic production of secondary metabolites. Among these secondary metabolite-inducing methods, mechanical wounding maintains the composition of secondary metabolites with little potential risk. However, the effects of mechanical stress have not been fully investigated, and thus this method remains widely unused.

Methods

In this study, we used metabolomics to investigate the metabolites produced in the upper and lower leaves of Catharanthus roseus in response to mechanical wounding.

Results

In the upper leaves, 13 different secondary metabolites (three terpenoid indole alkaloids and 10 phenolic compounds) were screened using an orthogonal partial least squares discriminant analysis (OPLS-DA) score plot. The mechanical wounding of different plant parts affected the production of secondary metabolites. Specifically, when lower leaves were mechanically wounded, the upper leaves became a strong source of resources. Conversely, when upper leaves were injured, the upper leaves themselves became a resource sink. Changes in the source-sink relationship reflected a new balance between resource tradeoff and the upregulation or downregulation of certain metabolic pathways.

Conclusion

Our findings suggest that mechanical wounding to specific plant parts is a novel approach to increase the biosynthetic production of specific secondary metabolites. These results indicate the need for a reevaluation of production practices for secondary metabolites from select commercial plants.

Photosynthetic, Biochemical and Secondary Metabolite Changes in a Medicinal Plant Chlorophytum borivillianum (Safed musli) against Low and High Doses of UV-B Radiation

Plants are inevitably grown in presence of sunlight, therefore bound to be exposed to natural UV-B radiation. Several studies have already been conducted with UV-B and medicinal plants and only few studies showed dose dependent variation. The present study aims to find out the variations and adaptation in Chlorophytum borivillianum under two different doses of UV-B radiation; ambient + low (3.2 kJm^-2  d^-1 ) and high (7.2 kJm^-2  d^-1 ) UV-B dose, denoted as LD and HD, respectively. Reduction in photosynthetic rate was higher at HD, while plants receiving LD displayed nonsignificant variation. During vegetative and reproductive stage, significant reduction (P ≤ 0.001) in stomatal conductance was obtained when exposed to HD-eUV-B. F_v /F_m showed more reductions in HD-eUV-B (12.6%) followed by LD-eUV-B (7.9%). Low and high doses of UV-B enhanced the anthocyanin content but the increase was significant in HD, indicates epidermal protection strategy by the plants. Under LD-eUV-B, the content of saponin, a major phytochemical constituent was enhanced by 26%. Phytochemical analysis of roots revealed reduction mostly in fatty acid components whereas the steroidal components (stigmasterol and sarsasapogenin) showed enhancement in response to LD. The study suggests the importance of LD-eUV-B in the stimulation of medicinal compounds in C. borivillianum.

Identification of bioactive compounds and cytogenotoxicity of the essential oil from the leaves of Croton heliotropiifolius Kunth

Croton heliotropiifolius Kunth, popularly known as "quince" and "velame," contains a high concentration of volatile oils in the leaves, and widely used in folk medicine as an antiseptic, analgesic, sedative, anti-inflammatory, spasmolytic and local anesthetic. The objectives of this investigation were to (1) identify the phytochemical compounds and (2) assess the cytogenotoxicity of the essential oil extracted from the leaves of C. heliotropiifolius Kunth. The oil was extracted utilizing hydrodistillation and phytochemical profile determined using gas chromatography and mass spectrometry (GCMS). In the toxicogenetics analysis, Allium cepa roots were exposed to 1% dimethylsulfoxide or methylmethanesulfonate (MMS, 10 µg/ml) negative and positive controls, respectively, and to C. heliotropiifolius oil at 6 concentrations (0.32; 1.6; 8; 40; 200 or 1000 µg/ml). The phytochemical profile exhibited 40 chromatographic bands, and 33 compounds identified. α-pinene (16.7%) and 1,8-cineole (13.81%) were identified as the major compounds. Some of these identified secondary metabolites displayed biological and pharmacological activities previously reported including antiseptic, analgesic, sedative, anti-inflammatory as well insecticidal, antiviral, anti-fungal actions. In the A. cepa test, C. heliotropiifolius leaves oil induced cytotoxicity at concentrations of 0.32, 1.6 or 200 µg/ml and genotoxicity at 200 or 1000 µg/ml as evidenced by increased presence of micronuclei and significant chromosomal losses. Based upon our observations data demonstrated that the essential oil of C. heliotropiifolius leaves contain monoterpene hydrocarbons, and oxygenated monoterpenes, sesquiterpenes, and oxygenated sesquiterpenes which are associated with cytotoxic and genotoxic responses noted in on A. cepa cells.

Phytochemistry and Antihyperglycemic Potential of Cistus salviifolius L., Cistaceae

Cistus salviifolius has been previously reported as a traditional remedy for hyperglycemia. However, the plant has been scarcely investigated from scientific point of view. Thus, the aim was to examine the chemical composition and to evaluate its antioxidant and antihyperglycemic potential in vitro. Aqueous and ethanolic extracts were evaluated for total phenolic, tannin, and flavonoid content using spectrophotometric methods. Detailed chemical characterization was performed by high-performance liquid chromatography (HPLC-DAD). The volatile organic compounds (VOCs) profile was assessed by gas chromatography technique. The potential in diabetes treatment was evaluated through tests of free radicals neutralization, inhibition of lipid peroxidation process, and test of ferric ion reduction; activity in tests of inhibition of α-amylase, α-glucosidase and dipeptidyl peptidase-4 was also evaluated. High content of phenolics (majority being tannins) was detected; detailed HPLC analysis revealed high content of gallic acid, followed by rutin, chlorogenic and caffeic acids. The VOCs analysis determined sesquiterpene hydrocarbons and oxygenated sesquiterpenes as the main groups of compounds. The assays classified extracts as potent neutralizers of 2,2-diphenyl-1-picrylhydrazil and nitroso radicals formation and potent inhibitors of α-amylase and α-glucosidase. In conclusion, Cistus salviifolius represents a rich source of phenolics and essential oil with sesquiterpenes. The established results suggested its promising antioxidant and antihyperglycemic activities.