Effects of UV-B radiation on secondary metabolite production, antioxidant activity, photosynthesis and herbivory interactions in Nymphoides humboldtiana (Menyanthaceae)

In vitro evaluation on the antioxidant and skin photo protection effects of lignans from the olive (Olea europaea) seed

The antioxidant and skin protectant-guided isolation of ethyl -acetate soluble fraction from olive seed led to the elucidating of three phenolic lignans and one phenolic aldehyde for the first time. Compounds (3) and (4) were reported in the oleaceae family for the first time. Their structures were characterised using NMR and HR-MS analysis as pinoresinol (1), olivil (2), 3,4,5-trimethoxybenzaldehyde (3) and medioresinol (4). All isolated compounds were investigated for antioxidant and skin photo protection activities on NHDF cells. Among them, compound (1) exhibited inhibition of UVB radiation of 300 mJ/cm2 on NHDF cells in a dose- dependent manner without any cytotoxic effect. Moreover, the capability of compound (1) to inhibit UVB-induced NHDF cell damage correlated to its potent DPPH radical scavenger (IC50 = 37.47 ± 2.2 µg/mL). This study highlights compound (1) offers a possible bioactive compound for natural skin photo protection in the future.

Multi-Omics Research Reveals the Effects of the ABA-Regulated Phenylpropanoid Biosynthesis Pathway on the UV-B Response in Rhododendron chrysanthum Pall

The growing depletion of the ozone layer has led to increased ultraviolet B (UV-B) radiation, prompting plants like the alpine Rhododendron chrysanthum Pall. (R. chrysanthum) to adapt to these harsh conditions. This study explored how abscisic acid (ABA) signaling influences R. chrysanthum's metabolic responses under UV-B stress. R. chrysanthum was treated with UV-B radiation and exogenous ABA for widely targeted metabolomics, transcriptomics, and proteomics assays, and relevant chlorophyll fluorescence parameters were also determined. It was observed that UV-B stress negatively impacts the plant's photosynthetic machinery, disrupting multiple metabolic processes. Multi-omics analysis revealed that ABA application mitigates the detrimental effects of UV-B on photosynthesis and bolsters the plant's antioxidant defenses. Additionally, both UV-B exposure and ABA treatment significantly influenced the phenylpropanoid biosynthesis pathway, activating key enzyme genes, such as 4CL, CCR, and HCT. The study also highlighted the MYB-bHLH-WD40 (MBW) complex's role in regulating this pathway and its interaction with ABA signaling components. These findings underscore ABA's crucial function in improving plant resistance to UV-B stress and offer novel insights into plant stress biology.

Iridoid Glycosides and Coumarin Glycoside Derivatives from the Roots of Nymphoides peltata and Their In Vitro Wound Healing Properties

Nymphoides peltata has been used as a medicinal herb in traditional medicines to treat strangury, polyuria, and swelling. The phytochemical investigation of the MeOH extract of N. peltata roots led to the isolation of three iridoid glycosides and three coumarin glycoside derivatives, which were characterized as menthiafolin (1), threoninosecologanin (2), callicoside C (3), and scopolin (4), as well as two undescribed peltatamarins A (5) and B (6). The chemical structures of the undescribed compounds were determined by analyzing their 1 dimensional (D) and 2D nuclear magnetic resonance (NMR) spectra and using high-resolution (HR)-electrospray ionization mass spectroscopy (ESI-MS), along with the chemical reaction of acid hydrolysis. The wound healing activities of the isolated compounds 1-6 were evaluated using a HaCaT cell scratch test. Among the isolates, scopolin (4) and peltatamarin A (5) promoted HaCaT cell migration over scratch wounds, and compound 5 was the most effective. Furthermore, compound 5 significantly promoted cell migration without adversely affecting cell proliferation, even when treated at a high dose (100 μM). Our results demonstrate that peltatamarin A (5), isolated from N. peltata roots, has the potential for wound healing effects.

3‴-O-Foliamenthoyl-Rutin, a New Flavonoid Glycoside from the Roots of Nymphoides peltata

Nymphoides peltata (Menyanthaceae) has been used as a medicinal herb in traditional medicines to treat conditions such as strangury, polyuria, swelling, and as a diuretic and antipyretic. In our ongoing research to discover novel structural and/or biological natural products in natural resources, five flavonoids, quercetin (1), quercitrin (2), isoquercetin (3), quercetin-3-O-vicianoside (4), and rutin (5), as well as a new flavonoid glycoside, 3‴-O-foliamenthoyl-rutin (6), were isolated from the MeOH extract of N. peltata roots. The chemical structure of the new compound (6) was determined by analyzing 1D and 2D NMR spectra and high-resolution (HR) electrospray ionization mass spectroscopy (ESIMS), along with a chemical reaction. The wound-healing activities of the isolated compounds (1-6) were evaluated using a HaCaT cell scratch test. Among the isolates, isoquercetin (3), quercetin-3-O-vicianoside (4), and 3‴-O-foliamenthoyl-rutin (6) promoted HaCaT cell migration over scratch wounds, with compound 4 being the most effective. Our findings provide experimental data supporting the potential of quercetin-3-O-vicianoside (4) as a wound-healing agent.

Undifferentiated Cells of Tessaria absinthioides with High Nutritional Value and Health-Promoting Phytochemicals. An Approach Based on Plant Cellular Agriculture

In vitro cultures of undifferentiated plant cells of Tessaria absinthioides, a native herb popularly recognized and used for its health benefits, were studied as potential food supplements. These tissues were incubated under two light conditions, and the biomass obtained was freeze-dried and oven-dried. To evaluate their nutritional value, their physicochemical and functional properties were determined. Although in some cases there were significant differences in the results according to the drying methodology applied, all these tissues presented a high proportion of proteins (23.6-28.3%), a low percentage of fats (< 2%) constituted mainly by phytosterols, and a significant amount of crude fibers (6.9-9.0%) and ashes (> 10%). In addition, the freeze-dried calli resulted in a product with better functional properties. On the other hand, their phytochemical profiles and antioxidant capacity were studied and compared with tissues from wild specimens and with green tea and chamomile as reference extracts.

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.

Light means power: harnessing light spectrum and UV-B to enhance photosynthesis and rutin levels in microtomato plants

Urban vertical agriculture with lighting system can be an alternative green infrastructure to increase local food production irrespective of environmental and soil conditions. In this system, light quality control can improve the plant physiological performance, well as induce metabolic pathways that contribute to producing phenolic compounds important to human health. Therefore, this study aimed to evaluate the influence of RBW (red, blue and white) and monochromatic (red and blue; R and B, respectively) light associated or not with UV-B on photosynthetic performance and phenolic compound production in microtomato fruits cultivated via vertical agriculture. The experimental design adopted was completely randomized, with six replicates illuminated with 300 µmol·m-2·s-1 light intensities (RBW, RBW + UV, B, B + UV, R, and R + UV), 12 h photoperiod, and 3.7 W·m-2 UV-B irradiation for 1 h daily for the physiological evaluations. Twenty-six days after the installation, gas exchange, chlorophyll a fluorescence and nocturnal breathing were evaluated. Fruits in different ripening stages (green, orange, and red) were collected from microtomato plants grown under with different light qualities, to evaluate the physiological performance. The identification and quantification of the phenolic compound rutin was also performed to investigate their metabolic response. This study identified that plants grown under B + UV had high photosynthetic rates (A=11.57 µmol·m-2·s-1) and the fruits at all maturation stages from plants grown under B and B + UV had high rutin content. Meanwhile, the activation of suppressive mechanisms was necessary in plants grown under R because of the high nocturnal respiration and unregulated quantum yield of the non-photochemical dissipation of the photosystem II. These results highlight the importance of selecting light wavelength for vegetable cultivation to produce fruits with a high content of specialized metabolites that influence color, flavor, and health promotion, which is of special interest to farmers using sustainable cropping systems.

Nymphoides peltata Root Extracts Improve Atopic Dermatitis by Regulating Skin Inflammatory and Anti-Oxidative Enzymes in 2,4-Dinitrochlorobenzene (DNCB)-Induced SKH-1 Hairless Mice

Nymphoides peltata is widely used pharmacologically in Traditional Chinese Medicine and Ayurvedic medicine as a diuretic, antipyretic, or choleretic and to treat ulcers, snakebites, and edema. Previous studies have shown that phytochemicals from N. peltata have physiological activities such as anti-inflammatory, anti-tumor, and anti-wrinkle properties. Nevertheless, research on the anti-atopic dermatitis (AD) effect of N. peltata extract is limited. This study was undertaken to assess the in vitro and in vivo anti-atopic and antioxidant activities of a 95% EtOH extract of N. peltata roots (NPR). PI-induced RBL-2H3 cells and two typical hapten mice (oxazolone-induced BALB/c mice and 2,4-dinitrochlorobenzene (DNCB)-induced SKH-1 hairless mice) were used to investigate the effect of NPR extract on AD. The expressions of AD-related inflammatory cytokines, skin-related genes, and antioxidant enzymes were analyzed by ELISA, immunoblotting, and immunofluorescence, and skin hydration was measured using Aquaflux AF103 and SKIN-O-MAT instruments. The chemical composition of NPR extract was analyzed using an HPLC-PDA system. In this study, NPR extracts were shown to most efficiently inhibit IL-4 in PI-induced RBL-2H3 cells and AD-like skin symptoms in oxazolone-BALB/c mice compared to its whole and aerial extracts. NPR extract markedly reduced DNCB-induced increases in mast cells, epidermal thickness, IL-4 and IgE expressions, and atopic-like symptoms in SKH-1 hairless mice. In addition, NPR extract suppressed DNCB-induced changes in the expressions of skin-related genes and skin hydration and activated the Nrf2/HO-1 pathway. Three phenolic acids (chlorogenic acid, 3,5-dicaffeoylquinic acid, and 3,4-dicaffeoylquinic acid) were identified by HPLC-PDA in NPR extract. The study shows that NPR extract exhibits anti-atopic activities by inhibiting inflammatory and oxidative stress and improving skin barrier functions, and indicates that NPR extract has potential therapeutic use for the prevention and treatment of AD.

How does UV-B stress affect secondary metabolites of Scutellaria baicalensis in vitro shoots grown at different 6-benzyl aminopurine concentrations?

Ultraviolet-B (UV-B) radiation is one of the abiotic stresses that can significantly affect the secondary metabolite accumulation in in vitro tissue cultures of medicinal plants. The present study investigated the effects of UV-B radiation on the secondary metabolites and antioxidant activities of Scutellaria baicalensis in vitro shoots grown at different concentrations of 6-benzyl aminopurine (6-BA), which is the cytokinin most widely used in plant tissue culture. The UV-B radiation caused significant increases in lipid peroxidation, total phenolic, and flavonoid contents, and antioxidant activities in the in vitro shoots grown at lower 6-BA concentrations (0 and 1 mg L^-1 ), while it did not cause any significant changes in those grown at higher 6-BA concentrations (2 and 3 mg L^-1 ). However, the UV-B radiation significantly altered the contents of main individual flavonoids at both lower and higher 6-BA concentrations. Upon UV-B radiation, aglycones (including baicalein, wogonin, and scutellarein) increased, while glucuronides such as baicalin and wogonoside decreased; this was more evident at higher 6-BA concentrations. This study demonstrated that the effects of UV-B radiation on the secondary metabolites of S. baicalensis in vitro shoots highly depended on the 6-BA concentration in the culture medium.

Antioxidant Activity of Plant-Derived Colorants for Potential Cosmetic Application

Application of plant-derived colorants in products, i.e., cosmetics or food, apart from imparting the desired color without harming the environment, may provide other benefits. Valuable ingredients in cosmetic formulations include antioxidants showing an advantageous effect on the skin by neutralizing free radicals that accelerate the aging process and cause skin defects. Antioxidant activity can be determined by chemical-based methods. The aim of this study was to determine the antioxidant activity of plant-derived colorants (purple and red colorant) by two methods: CUPRAC and DPPH free-radical scavenging activity. Antioxidant activity evaluation using both methods for colorants samples was also performed after 5, 15, 30, and 60 min of exposure to UVC irradiation. The results obtained by CUPRAC method were for purple and red colorant unexposed samples as follows: 6.87 ± 0.09 and 4.48 ± 0.14 mg/100 mg colorant expressed as caffeic acid equivalent, respectively. UVC treatment did not affect the results of the antioxidant activity for red colorant and for the purple one only a slight influence was observed. DPPH free-radical scavenging activity for unexposed samples was 70.06 ± 7.74% DPPH/100 mg colorant for the red colorant and 96.11 ± 3.80% DPPH/100 mg colorant for the purple one.

Flavonoids Extraction Kinetics, Antimicrobial Activity and Radical Scavenging Potential of Bulgarian Woundwort (Solidago virgaurea L.)

The medicinal plant woundwort (Solidago virgaurea L.) characterizes by diuretic, antimutagenic, anti-inflammatory activity and it has been applied for urinary tract, nephrolithiasis and prostate disorders treatment. The aim of the present study was to analyze the extraction kinetics of catechin, epigallocatechin and quercetin from Bulgarian woundwort extracts, to assess the antibacterial potential of the medicinal plant extracts against four bacterial strains (Staphylococcus aureus ATCC25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853 and Bacillus cereus), their antioxidant capacity and radical scavenging potential. The concentrations of the flavonoids in the extracts obtained at different extraction conditions (solvent, temperature, extraction time) were determined by newly-developed by the scientific team RP-HPLC-PDA methodologies. The agar well diffusion method was applied to evaluate the antibacterial activity of the plant extracts. The 70% EtOH extracts at 20 °C displayed significantly higher antibacterial activity against the foodborne pathogenic bacteria S. aureus and P. aeruginosa as compared to the 70% and 98% EtOH extracts at 30 °C and 20 °C, respectively. The medicinal plant exhibited satisfactory antioxidant potential and radical-scavenging activity.

Vaccinium myrtillus L. extract associated with octocrylene, bisoctrizole and titanium dioxide: in vitro and in vivo tests to evaluate safety and efficacy

OBJECTIVE

The harmful effects induced by ultraviolet exposition and the significant increment in skin cancer diagnosis confirm the necessity to develop effective and safe sunscreens. Limited efficacy and cutaneous adverse reactions of traditional formulations drove the incorporation of natural extracts into multifunctional sunscreens. Vaccinium myrtillus L. extract (VME), that contains anthocyanins and flavonoids, is a potential candidate for such systems.

METHODS

Considering that, we performed in vitro and in vivo tests to evaluate the sun protection factor (SPF), photostability and safety of sunscreen samples containing VME.

RESULTS

As main results, the SPF was reduced in both in vitro and in vivo evaluation in the presence of VME, nonetheless, the samples were photostable and safe.

CONCLUSION

Further investigation is required to better understand the unexpected effects of VME over photoprotection, decreasing the SPF value. As a conclusion, even with interesting findings, we highlight the importance of case-by-case investigations to develop multifunctional bioactive sunscreens.

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

Plant secondary metabolites are known to have a variety of biological activities beneficial to human health. They are becoming more popular as a result of their unique features and account for a major portion of the pharmacological industry. However, obtaining secondary metabolites directly from wild plants has substantial drawbacks, such as taking a long time, posing a risk of species extinction owing to over-exploitation, and producing a limited quantity. Thus, there is a paradigm shift towards the employment of plant tissue culture techniques for the production of key secondary metabolites in vitro. Elicitation appears to be a viable method for increasing phytochemical content and improving the quality of medicinal plants and fruits and vegetables. In vitro culture elicitation activates the plant's defense response and increases the synthesis of secondary metabolites in larger proportions, which are helpful for therapeutic purposes. In this respect, light has emerged as a unique and efficient elicitor for enhancing the in vitro production of pharmacologically important secondary metabolites. Various types of light (UV, fluorescent, and LEDs) have been found as elicitors of secondary metabolites, which are described in this review.

β-Sitosterol differentially regulates key metabolites for growth improvement and stress tolerance in rice plants during prolonged UV-B stress

BACKGROUND

Elevated ultraviolet-B (UV-B) radiation is potentially deleterious to many organisms specifically crop plants and has become a global challenge. Rice is an exceptionally important staple food which is grown worldwide, and many efforts have been done recently to improve rice varieties against UV-B stress. This current study aims to investigate the effects of exogenous application of β-sitosterol (βSito) on growth improvement and tolerance level of rice plants against prolonged UV-B stress. The physiological and metabolic responses were evaluated in rice plants not supplemented with βSito (Nβ) and those supplemented with βSito (Sβ).

RESULTS

The Nβ and Sβ plants were grown under non-stress (ns) and under prolonged UV-B stress (uvs) conditions and termed as Nβ^ns, Sβ^ns and Nβ^uvs, Sβ^uvs, respectively. The application of βSito contributes positively under non-stress and specifically to UV-B stress in terms of improving numerous physiological parameters associated with growth and development such as shoot and root length, RWC, whole plant biomass, chlorophyll pigments, and photosynthetic-related parameters (Pn, Gs, Tr, WUEi, Fv/Fm, and NPQ) in Sβ compared with Nβ plants. Moreover, enhanced oxidative stress tolerance of Sβ^uvs vs. Nβ^uvs plants under stress was attributed to low levels of ROS and substantial trigger in activities of antioxidant enzymes (SOD, POD, CAT, and APX). Metabolic analysis was performed using GC-TOFMS, which revealed higher accumulation of several key metabolites including organic acids, sugars, amino acids, and others in Sβ^uvs vs. Nβ^uvs plants, which were mainly reduced in Nβ plants under stress vs. non-stress conditions.

CONCLUSION

These results provide useful data regarding the important role of βSito on growth maintenance and modulation of several metabolites associated with osmotic and redox adjustments during UV-B stress tolerance in rice plants. Importantly, βSito-regulated plasticity could further be explored specifically in relation to different environmental stresses in other economically useful crop plants.

Cationic zinc (II) phthalocyanine nanoemulsions for photodynamic inactivation of resistant bacterial strains

BACKGROUND

The growing emergence of microbial resistance to antibiotics represents a worldwide challenge. Antimicrobial photodynamic inactivation (aPDI) has been introduced as an alternative technique, especially when combined with nanotechnology. Therefore, this study was designed to investigate the therapeutic merits of combined aPDI and nanoemulsion in infections caused by resistant bacterial strains.

METHODS

Cationic zinc (II) phthalocyanine nanoemulsions (ZnPc-NE) were prepared using isopropyl myristate (IPM) as oil phase, egg phosphatidylcholine (egg PC) as emulsifier, and N-cetyl-N,N,N-trimethyl ammonium bromide (CTAB). Nanoemulsions were characterized for particle size, polydispersity, zeta potential, viscosity, and skin deposition. The in-vitro aPDI was investigated on human resistant pathogens; gram-positive methicillin-resistant Staphylococcus aureus (MRSA) and gram-negative Multidrug-resistant strain of Escherichia coli (MDR E. coli), under different experimental conditions. In addition, in-vivo model of abrasion wound infected by MDR E. coli was induced in rats to investigate the therapeutic potential of the selected formulation.

RESULTS

It was evident that the selected ZnPc formulation (20 % IPM, 2 % egg PC and 0.5 % CTAB) displayed a particle size of 209.9 nm, zeta potential +73.1 mV, and 23.66 % deposition of ZnPc in skin layers. Furthermore, the selected formulation combined with light achieved almost 100 % eradication of the two bacterial strains, with superior bacterial load reduction and wound healing propertiesin-vivo, compared to either the nanoemulsion formulation or laser alone.

CONCLUSION

ZnPc nanoemulsion improved antimicrobial photodynamic therapy in inactivating resistant bacterial infections and provided a promising therapeutic means of treating serious infections, and hence could be applied in diseases caused by other bacterial strains.

The Callus of Phaseolus coccineus and Glycine max Biotransform Flavanones into the Corresponding Flavones

In vitro plant cultures are gaining in industrial importance, especially as biocatalysts and as sources of secondary metabolites used in pharmacy. The idea that guided us in our research was to evaluate the biocatalytic potential of newly obtained callus tissue towards flavonoid compounds. In this publication, we describe new ways of using callus cultures in the biotransformations. In the first method, the callus cultures grown on a solid medium are transferred to the water, the reaction medium into which the substrate is introduced. In the second method, biotransformation is carried out on a solid medium by growing callus cultures. In the course of the research, we have shown that the callus obtained from Phaseolus coccineus and Glycine max is capable of converting flavanone, 5-methoxyflavanone and 6-methoxyflavanone into the corresponding flavones.