Use of ultra-high-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry system as valuable tool for an untargeted metabolomic profiling of Rumex tunetanus flowers and stems and contribution to the antioxidant activity

Unravelling the Phytochemical Composition and Antioxidant Potential of Different Parts of Rumex vesicarius L.: A RP-HPLC-MS-MS/MS, Chemometrics, and Molecular Docking-Based Comparative Study

Rumex vesicarius L. Polygonaceae is a wildly grown plant in Egypt, North Africa, and Asia with wide traditional uses. Several studies reported its biological activities and richness in phytochemicals. This research addresses a comprehensive metabolic profiling of the flowers, leaves, stems, and roots via RP-HPLC-QTOF-MS and MS/MS with chemometrics. A total of 60 metabolites were observed and grouped into phenolic acids, flavonoids, phenols, terpenes, amino acids, fatty acids, organic acids, and sugars. Principal component analysis and hierarchal cluster analysis showed the segregation of different parts. Moreover, the antioxidant capacity was determined via several methods and agreed with the previous results. Additionally, an in silico approach of molecular docking of the predominant bioactive metabolites was employed against two antioxidant targets, NADPH oxidase and human peroxiredoxin 5 enzyme (PDB ID: 2CDU and 1HD2) receptors, alongside ADME predictions. The molecular modelling revealed that most of the approached molecules were specifically binding with the tested enzymes, achieving high binding affinities. The results confirmed that R. vesicarius stems and roots are rich sources of bioactive antioxidant components. To our knowledge, this is the first comprehensive metabolic profiling of R. vesicarius giving a prospect of its relevance in the development of new naturally based antioxidants.

A multidimensional strategy for characterization, distinction, and quality control of two Clinopodium medicinal plants

ETHNOPHARMACOLOGICAL RELEVANCE

Clinopodium chinense Kuntze (CC) and Clinopodium polycephalum (Vaniot) C. Y. Wu & S. J. Hsuan (CP) are both included in the Pharmacopoeia of the People's Republic of China (edition 2020) as the legitimate source of "Duan Xue Liu" (DXL), which is a crucial traditional Chinese medicine used as a clinical remedy for bleeding diseases. However, the differences in plant endogenous metabolites and bioactivities between CC and CP are still unclear.

AIM OF THE STUDY

This study aims to provide a scientific basis to investigate the differences between CC and CP ensuring the efficient and safe use of DXL.

MATERIALS AND METHODS

A multidimensional strategy including plant metabolomics, digital reference standard (DRS) analyzer, and biological activities assay was creatively constructed for the characterization, distinction, and quality control of CC and CP.

RESULTS

There were apparent differences in the metabolites between CC and CP. 7 compounds contributing to the differences were successfully identified. On that basis, linear calibration using two reference substances (LCTRS) methods was proved as a more accurate and specific quality analysis method for CC and CP. In addition, bioactivity assays showed that both CC and CP exhibited obvious hemostatic activity, while CC showed greater potential to resist inflammation and free radicals.

CONCLUSION

In summary, it was the first time to investigate the chemical constituents and bioactivities differences between CC and CP with the help of plant metabolomics, DRS study, and biological activity assays. These two plants were significantly separated in the integrated analysis, suggesting that we should pay attention to the distinction to prevent unexpected risks caused by medicinal materials.

Insights into the phytochemical composition and antioxidant potential of the Tunisian Ceratonia siliqua L

Carob (Ceratonia siliqua L.) corresponds to an evergreen leguminous tree (Fabaceae family). The high phenolic content of numerous parts of carob has been deeply associated with several nutritional and functional benefits. The aim of this study was to investigate the physicochemical properties of ground carob pods and seeds, the effect of different extraction procedures as well a comprehensive phytochemical characterization of hydro-methanolic extracts (80/20 v/v) of pods and seeds by HPLC-DAD ESI-Q-TOF-MS/MS. Additionally, their antioxidant activity was evaluated using in vitro assays. The results showed thatthe dry matter (DM) values were 88.09% for pods and 89.10% for seeds, protein contents were 0.41 g/100 g DM for pods and 0.88 g/100 g DM for seedsand total sugars contents were 0.35 g/100 DM for pods and 26.70 g/100 g DM for seeds. Furthermore, the oil holding capacities (OHC) were 10.43 g/g for pods and 7.53 g/g for seeds, while the water holding capacities were 8.46 g/g for pods and 2.59 g/g for seeds.The hydro-methanolic extracts of both pods and seeds showed the presence of 53 secondary bioactive metabolites belonging to various classes(flavonoids, phenolic acids, tannins and non-phenolic compounds). The antioxidant activities were evidenced in DPPH (22.24 mg/ml for pods and 26.37 mg/ml for seeds), ABTS (198.50 mmol Eq Trolox/100 g for pods and 201.04 mmol Eq Trolox/100 g for seeds) and FRAP (0.39 mmol Eq Trolox/100 g for pods and 0.53 mmol Eq Trolox/100 g for seeds).Moreover,high significant (p ≤ 0.01) correlation coefficients were found between the antioxidant activity estimated by the DPPH method and total phenols (r = 0.943), orthodiphenols (r = 0.996), flavonoids (r = 0.880) and flavonols (r = 0.982). Nevertheless, lower correlations were detected with ABTS and FRAP methods.These results demonstrated that carob parts displayed an interesting potential that can be of interest for further valorizations as a natural antioxidant with multiple applications, namely functional food ingredients or prevention of many health problems.

Appetite Suppressing Activity of Rumex Usambarensis Leaf and Stem Aqueous Extract in Wistar Albino Female Rats: an in vivo Experimental Study

Background

The burden of obesity and overweight associated morbidity and mortality is increasing in epidemic proportions worldwide. Suppression of appetite is one of the mechanisms that has been shown to reduce weight. Most of the drugs on the market currently for appetite suppression are not readily available or affordable in resource-limited settings. Additionally, previous studies have shown that most of these drugs are associated with significant adverse effects, which demonstrates a need for alternative or complementary options of drugs for appetite suppression. In Uganda, herdsmen commonly chew the raw stems and leaves of Rumex usambarensis, a wild shrub, and this is believed to reduce hunger. This study aimed at determining the effect of Rumex usambarensis aqueous extract on food intake as a measure of appetite in Wistar albino rats.

Methods

This study was carried out in two phases: the fattening phase and the treatment phase. Female albino Wistar rats were fed a high-fat diet for 49 days. The fattened animals were then randomly separated into 4 groups, which received 1 mL of distilled water (negative control), 500 mg/kg body weight of aqueous extract of Rumex usambarensis, 1000 mg/kg body weight of the extract and 20 mg/kg body weight topiramate (positive control), respectively. Food intake was measured every day, and weights were taken every two days for every group.

Results

Rumex usambarensis extract significantly reduced body weight of fattened rats compared to the control group at both doses: for the 500mg/kg dose (Mean difference, MD = 17.2, p < 0.001) and for 1000mg/kg dose (MD = 25.9, p < 0.001). Additionally, both doses of the aqueous extract showed a significant reduction in food intake: for the 500mg/kg dose (MD = 16.1, p < 0.001) and for the 1000mg/kg dose (MD = 37.3, p < 0.001). There was a strong correlation between food intake and weight for both doses for the 500mg/kg dose (r = 0.744, p = 0.009), and the strongest association observed with 1000mg/kg dose (r = 0.906, p < 0.001).

Conclusion

The aqueous extract of the leaves and stems of Rumex usambarensis has appetite suppressing and weight reduction effects in fattened female Wistar albino rats and could be an efficacious alternative medicine for management of overweight, obesity and other related disorders.

Comparative analysis of flavonoid metabolites from different parts of Hemerocallis citrina

BACKGROUND

Hemerocallis citrina Baroni is a traditional medical and edible plant. It is rich in flavonoid compounds, which are a kind of important bioactive components with various health benefits and pharmaceutical value. However, the flavonoid metabolomics profile and the comparison of flavonoid compounds from different parts of H. citrina is scarce.

RESULTS

In this study, flavonoid metabolites were investigated from roots, stems, leaves and flowers of H. citrina. A total of 364 flavonoid metabolites were identified by UPLC-MS/MS based widely targeted metabolomics, and the four plant parts showed huge differences at flavonoid metabolic level. Compared to roots, 185, 234, and 119 metabolites accounted for upregulated differential flavonoid metabolites (DFMs) in stems, leaves, and flowers, respectively. Compared to stems, 168 and 29 flavonoid metabolites accounted for upregulated DFMs in leaves and flowers, respectively. Compared to leaves, only 29 flavonoid metabolites accounted for upregulated DFMs in flowers. A number of 35 common flavonoid metabolites were observed among six comparison groups, and each comparison group had its unique differential metabolites. The most abundant flavonoid metabolites in the four parts are flavonols and flavones, followed by flavanones, chalcones, flavanols, flavanonols, anthocyanidins, tannin, and proanthocyanidins. 6,7,8-Tetrahydroxy-5-methoxyflavone, 7,8,3',4'-tetrahydroxyflavone, 1-Hydroxy-2,3,8-trimethoxyxanthone, Farrerol-7-O-glucoside, 3',7-dihydroxy-4'-methoxyflavone, 3,3'-O-Dimethylellagic Acid, 5-Hydroxy-6,7-dimethoxyflavone, Nepetin (5,7,3',4'-Tetrahydroxy-6-methoxyflavone), (2s)-4,8,10-trihydroxy-2-methoxy-1 h,2 h-furo[3,2-a]xanthen-11-one are dominant in roots. Isorhamnetin-3-O-(6''-malonyl)glucoside-7-O-rhamnoside, 7-Benzyloxy-5-hydroxy-3',4'-methylenedioxyflavonoid, 3-Hydroxyphloretin-4'-O-glucoside are dominant in stems. Chrysoeriol-7-O-glucoside, Epicatechin glucoside, Kaempferol-3-O-rhamnoside (Afzelin)(Kaempferin)*, Azaleatin (5-O-Methylquercetin), Chrysoeriol-5-O-glucoside, Nepetin-7-O-glucoside(Nepitrin), 3,5,7,2'-Tetrahydroxyflavone; Datiscetin, Procyanidin B2*, Procyanidin B3*, Procyanidin B1, Isorhamnetin-3-O-(6''-acetylglucoside) are dominant in leaves. kaempferol-3-p-coumaroyldiglucoside, Delphinidin-3-O-sophoroside-5-O-glucoside, Limocitrin-3-O-sophoroside, Kaempferol-3-O-rutinoside(Nicotiflorin), Luteolin-7-O-(6''-malonyl)glucoside-5-O-rhamnoside are dominant in flowers.

CONCLUSION

There was significant difference in flavonoid metabolites among different parts of H. citrina. Leaves had relative higher metabolites contents than other parts. This study provided biological and chemical evidence for the different uses of various plant parts of H. citrina, and these informations are important theoretical basis for the food industry, and medical treatment.

Untargeted Phytochemical Profiling, Antioxidant, and Antimicrobial Activities of a Tunisian Capsicum annuum Cultivar

Peppers are among the spices possessing a wide plethora of biological properties due to their excellent supply of health-related metabolites. Capsicum annuum L. (Solanaceae) is cultivated throughout Tunisia, and there is a shortage of information on the identification of the secondary metabolites in the seeds of this species as well as on their biological activities. In the present work, we intended to undertake a chemical characterization of the bioactive compounds from the hydro-methanolic seed extract of C. annuum as well as an evaluation of its broad spectrum of antimicrobial and antioxidant activities. The chemical profile was evaluated by RP-HPLC-DAD-QTOF-MS/MS, whereas the total phenol and flavonoid content, antioxidant, and antimicrobial activities were determined in in vitro assays. In this work, 45 compounds belonging to various phytochemical classes, such as organic acids (2), phenolic compounds (4 phenolic acids and 5 flavonoids), capsaicinoids (3), capsianosides (5), fatty acids (13), amino acids (1), sphingolipids (10), and steroids (2) were identified in the hydro-methanolic seed extract of C. annuum. The phenolic and flavonoid content (193.7 mg GAE/g DW and 25.1 mg QE/g DW, respectively) of the C. annuum extract correlated with the high antiradical activity (IC50 = 45.0 µg/mL), reducing power (EC50 = 61.3 µg/mL) and chelating power (IC50 = 79.0 µg/mL) activities. The hydro-methanolic seed extract showed an important antimicrobial activity against seven bacterial and four fungal strains. In fact, the inhibition zones (IZs) for bacteria ranged from 9.00 ± 1.00 mm to 12.00 ± 0.00 mm; for fungi, the IZs ranged from 12.66 ± 0.57 mm to 13.66 ± 0.57 mm. The minimal inhibition concentration and minimal bactericidal concentration values showed that the extract was more effective against fungi than bacteria.

Evaluation of α-Glucosidase Inhibition and Antihyperglycemic Activity of Extracts Obtained from Leaves and Flowers of Rumex crispus L

Among antihyperglycemic drugs used for treating diabetes, α-glucosidase inhibitors generate the least adverse effects. This contribution aimed to evaluate the potential antidiabetic activity of Rumex crispus L. by testing its in vitro α-glucosidase inhibition and in vivo antihyperglycemic effects on rats with streptozotocin (STZ)-induced diabetes. Better inhibition of α-glucosidase was found with the methanol extract versus the n-hexane and dichloromethane extracts. The methanol extract of the flowers (RCFM) was more effective than that of the leaves (RCHM), with an IC50 of 7.3 ± 0.17 μg/mL for RCFM and 112.0 ± 1.23 μg/mL for RCHM. A bioactive fraction (F89s) also showed good α-glucosidase inhibition (IC50 = 3.8 ± 0.11 μg/mL). In a preliminary study, RCHM and RCFM at 150 mg/kg and F89s at 75 mg/kg after 30 days showed a significant effect on hyperglycemia, reducing glucose levels (82.2, 80.1, and 84.1%, respectively), and improved the lipid, renal, and hepatic profiles of the rats, comparable with the effects of metformin and acarbose. According to the results, the activity of R. crispus L. may be mediated by a diminished rate of disaccharide hydrolysis, associated with the inhibition of α-glucosidase. Thus, R. crispus L. holds promise for the development of auxiliary drugs to treat diabetes mellitus.

Metabolite Profiling and Bioactivities of Leaves, Stems, and Flowers of Rumex usambarensis (Dammer) Dammer, a Traditional African Medicinal Plant

The comprehensive identification of secondary metabolites represents a fundamental step for the assessment of bioactivities and pharmacological properties of traditional herbal drugs. Rumex usambarensis (Dammer) Dammer has been described as a multipurpose remedy in different African traditional pharmacopoeias, but its phytochemical profile has not been properly investigated. Herein we report a high throughput metabolomic screening, based on ultra-high performance liquid chromatography-travelling wave ion mobility spectrometry quadrupole time-of-flight (UHPLC-TWINS-QTOF), which was performed for the first time on different R. usambarensis plant parts. By applying high-resolution mass spectrometry-based metabolomics and chemometric analysis, a complete discrimination of different aerial parts was obtained, with the annotation of 153 significant metabolites in leaves, stems, and flowers, suggesting an easy authentication and discrimination route. Phytochemical data were correlated to antimicrobial and antioxidant properties. Flavonoids, benzopyranes, chromones, and xanthones derivatives, along with a richer phytocomplex, might be responsible for the stronger bioactivities obtained from flowers.

Analysis of flavonoid-related metabolites in different tissues and fruit developmental stages of blackberry based on metabolome analysis

Blackberry is an economically important shrub species of Rubus in the Rosaceae family. It is rich in phenolic compounds, which have many health effects and pharmaceutical value. The utilization of metabolites from various blackberry tissues is still in the primary stage of development, so investigating the metabolites in various tissues is of practical significance. In this study, nontargeted LC - MS metabolomics was used to identify and measure metabolites in the roots, stems, leaves and fruits (green, red, and black fruits) of blackberry "Chester". We found that 1,427 and 874 metabolites were annotated in the positive and negative ion modes (POS; NEG), respectively. Differentially abundant metabolites (DAMs) between the leaf and root groups were the most abundant (POS: 249; NEG: 141), and the DAMs between the green and red fruit groups were the least abundant (POS: 21; NEG: 14). Moreover, the DAMs in different fruit development stages were far less than those in different tissues. There were significant differences in flavonoid biosynthesis-related pathways among the comparison groups. Trend analysis showed that the profile 10 had the largest number of metabolites. This study provides a scientific basis for the classification and efficient utilization of resources in various tissues of blackberry plants and the directional development of blackberry products.

Bioactivities and phenolic composition of Limonium boitardii Maire and L. cercinense Brullo & Erben (Plumbaginaceae): two Tunisian strict endemic plants

Limonium genus is traditionally used in North Africa for disease treatment and in cosmetic. This study investigates for the first time the antioxidant, anti-inflammatory and enzyme inhibitory activities of two Tunisian endemic plants, L. boitardii and L. cercinense. Analysis of phenolic compounds was carried out by using RP-HPLC. Total phenolic and flavonoid contents, antioxidant activity (antiradical, reducing and total antioxidant activities), tyrosinase and α-glucosidase, collagenase inhibition activities were determined. Inhibiting of NO release in LPS-stimulated macrophages was assessed. L. cercinense exhibited strong antioxidant and anti-inflammatory effects. In the tyrosinase and α-glucosidase inhibitor activity tests, the two species were highly active, especially L. cercinense. High total phenolic and flavonoid contents were recorded in L. cercinense and myricitrin, myricetin, myricetin 3-O-β-D-galatopyranoside, luteolin 7-O-glucoside and rutin were the main phenolics in both species. The results obtained render L. boitardii and L. cercinense as valuable new natural sources for cosmetic and pharmacological applications.

Use of High-Performance Liquid Chromatography/Electrospray Ionization Mass Spectrometry for Structural Characterization of Bioactive Compounds in the Olive Root Bark and Wood of Chemlali Cultivar

This report aims to provide complete knowledge on the polyphenol composition and biological activities of the olive tree. The extraction of the root bark and wood of Olea europaea. L (Chemlali cultivar) was realized by solid-liquid ethanolic extraction, whose analysis was conducted via high-performance liquid chromatography equipped with photodiode array detection and mass spectrometry (HPLC-ESI-DAD and MS/MS). Moreover, radical scavenging and antibacterial activities were determined. The results present a total of 14 phenolic compounds belonging mainly to secoiridoid and flavonoid subclasses. Oleuropein was found to be the most abundant compound at an amount of up to 7000 mg/kg followed by ligstroside and oleuropein derivatives. In addition, we found oleocanthal at a great amount (2115 mg/kg). Higher individual polyphenolic concentrations were recorded in root wood extracts compared to bark ones, except for the flavonoid group. Likewise, the total phenolic compound contents increased in the olive root wood. This trend was reflected in biological activities. In fact, root wood extracts exert more important antioxidant and antibacterial activities than bark extracts due to their high bioactive compounds.

Bridging the Chemical Profiles and Biological Effects of Spathodea campanulata Extracts: A New Contribution on the Road from Natural Treasure to Pharmacy Shelves

Spathodea campanulata is an important medicinal plant with traditional uses in the tropical zone. In the current work, we aimed to determine the chemical profiles and biological effects of extracts (methanolic and infusion (water)) from the leaves and stem bark of S. campanulata. The chemical components of the tested extracts were identified using LC-ESI-QTOF-MS. Biological effects were tested in terms of antioxidant (radical scavenging, reducing power, and metal chelating), enzyme inhibitory (cholinesterase, amylase, glucosidase, and tyrosinase), antineoplastic, and antiviral activities. Fifty-seven components were identified in the tested extracts, including iridoids, flavonoids, and phenolic acids as the main constituents. In general, the leaves-MeOH extract was the most active in the antioxidant assays (DPPH, ABTS, CUPRAC, FRAP, metal chelating, and phosphomolybdenum). Antineoplastic effects were tested in normal (VERO cell line) and cancer cell lines (FaDu, HeLa, and RKO). The leaf infusion, as well as the extracts obtained from stem bark, showed antineoplastic activity (CC₅₀ 119.03–222.07 µg/mL). Antiviral effects were tested against HHV-1 and CVB3, and the leaf methanolic extract (500 µg/mL) exerted antiviral activity towards HHV-1, inhibiting the viral-induced cytopathic effect and reducing the viral infectious titre by 5.11 log and viral load by 1.45 log. In addition, molecular docking was performed to understand the interactions between selected chemical components and viral targets (HSV-1 DNA polymerase, HSV-1 protease, and HSV-1 thymidine kinase). The results presented suggest that S. campanulata may be a bright spot in moving from natural sources to industrial applications, including novel drugs, cosmeceuticals, and nutraceuticals.

The genus Rumex (Polygonaceae): an ethnobotanical, phytochemical and pharmacological review

Rumex L., a genus in Polygonaceae family with about 200 species, is growing widely around the world. Some Rumex species, called "sorrel" or "dock", have been used as food application and treatment of skin diseases and hemostasis after trauma by the local people of its growing areas for centuries. To date, 29 Rumex species have been studied to contain about 268 substances, including anthraquinones, flavonoids, naphthalenes, stilbenes, diterpene alkaloids, terpenes, lignans, and tannins. Crude extract of Rumex spp. and the pure isolates displayed various bioactivities, such as antibacterial, anti-inflammatory, antitumor, antioxidant, cardiovascular protection and antiaging activities. Rumex species have important potential to become a clinical medicinal source in future. This review covers research articles from 1900 to 2022, fetched from SciFinder, Web of Science, ResearchGate, CNKI and Google Scholar, using "Rumex" as a search term ("all fields") with no specific time frame set for the search. Thirty-five Rumex species were selected and summarized on their geographical distribution, edible parts, traditional uses, chemical research and pharmacological properties.

RP-UHPLC-DAD-QTOF-MS As a Powerful Tool of Oleuropein and Ligstroside Characterization in Olive-Leaf Extract and Their Contribution to the Improved Performance of Refined Olive-Pomace Oil during Heating

Since olive leaf is a potential source of phenolic fraction that is assumed to have good antioxidative effects, we purposed to add its extract to the refined olive-pomace oil during heating to increase its oxidative stability. RP-UHPLC-DAD-QTOF-MS was employed to characterize the phenolic fraction.The oil samples were evaluated by measuring the polymers and the polar compounds and thus detecting specific oxidized compounds. Using this approach, the results showed that incorporating olive leaf extract in refined oil significantly reduced the formation of polymers from 14.39% to 10.45% and the oxidation state by the variation of extinction ΔK from 3.02 to 2.29 during 20 h of heating compared to unenriched oil. This study has proven that the use of natural substances is an opportunity to extend the life of refined oils.

Untargeted metabolite profiling and phytochemical analysis based on RP-HPLC-DAD-QTOF-MS and MS/MS for discovering new bioactive compounds in Rumex algeriensis flowers and stems

INTRODUCTION

Natural products with distinctive pharmaceutical activities are considered as the main source of new herbal drugs, functional foods and cosmetic additives. Rumex algeriensis is an endemic medicinal plant with no accessible information about its chemical profile and biological activities.

OBJECTIVE

In the quest for new sources of biologically-active compounds, we intended in the present work to undertake a comprehensive characterisation of phytochemical compounds from Rumex algeriensis flowers and stems hydro-methanolic extract.

METHODOLOGY

Chemical profiles were evaluated by a rapid analytical method reversed-phase high-performance liquid chromatography (RP-HPLC) coupled to electrospray ionisation-quadrupole-time-of-flight mass spectrometry (ESI-QTOF-MS) and tandem mass spectrometry (MS/MS) using negative and positive ions modes.

RESULTS

In this work, 44 bioactive compounds were tentatively identified using high mass accuracy data and confirmed by MS/MS experiments, among which five compounds were reported for the first time in the Polygonaceae family. These compounds were classified as sugars, hydroxybenzoic acids, hydroxycinnamic acids, flavonols, flavanones, flavone, flavanols, condensed tannins, hydrolysable tannins and their conjugated derivatives.

CONCLUSIONS

The obtained results highlighted that Rumex algeriensis, even though undervalued and unexplored, contributes to the preclinical knowledge that could be considered as a renewable source of nutraceutical compounds that may be exploited in novel herbal medicinal products, in the food, pharmaceutical and nutraceutical industries.

Agrobacterium rhizogenes mediated transformation of Ficus carica L. for the efficient production of secondary metabolites

BACKGROUND

Ficus carica L., an ancient source of food and medicines, is rich in valuable nutritional and secondary compounds with antioxidant, antimicrobial, and anticancer effects. The present study is the first attempt to examine hairy root (HR) induction of F. carica (Sabz and Siah) by inoculating the 3-week-old shoots and leaves with different strains of Agrobacterium rhizogenes and also to investigate methyl jasmonate (MeJA) elicitation of HRs to produce a fast and high-yield production method for secondary metabolites.

RESULTS

The maximum transformation rate (100%) was achieved by inoculating the shoots with Agrobacterium rhizogenes strain A7. Siah HRs elicited with 100 and 200 μmol L^-1 MeJA and Sabz HRs with 100 μmol L^-1 MeJA showed the highest total phenolic content. The highest flavonoid content was 3.935 mg QE g^-1 DW in Siah HRs treated with 200 μmol L^-1 MeJA and 2.762 mg QE g^-1 DW in Sabz HRs treated with 300 μmol L^-1 MeJA. The 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity and ferric reducing antioxidant power (FRAP) value of HRs were affected by MeJA treatments. Methyl jasmonate elicitation also significantly enhanced the content of six phenolic acids (gallic acid, caffeic acid, chlorogenic acid, coumaric acid, rosmarinic acid, and cinnamic acid) and three flavonoids (rutin, quercetin, and apigenin). Thymol, a monoterpene phenol, was the main HR compound detected in gas chromatography mass spectrometry (GC-MS) analysis of the essential oils.

CONCLUSION

Induction of HRs and elicitation of F. carica HRs by MeJA resulted in a significant increase in the production of important phenolic compounds and a significant increase in antioxidant capacity. © 2020 Society of Chemical Industry.