LC-HRMS/MS phytochemical profiling of Symphytum officinale L. and Anchusa ochroleuca M. Bieb. (Boraginaceae): Unveiling their multi-biological potential via an integrated approach

Phytochemical profiling and bioactivity assessment of underutilized Symphytum species in comparison with Symphytum officinale

BACKGROUND

Symphytum (comfrey) genus, particularly Symphytum officinale, has been empirically used in folk medicine mainly for its potent anti-inflammatory properties. In an attempt to shed light on the valorization of less known taxa, the current study evaluated the metabolite profile and antioxidant and enzyme inhibitory effects of nine Symphytum species.

RESULTS

Phenolic acids, flavonoids and pyrrolizidine alkaloids were the most representative compounds in all comfrey samples. Hierarchical cluster analysis revealed that, within the roots, S. grandiflorum was slightly different from S. ibericum, S. caucasicum and the remaining species. Within the aerial parts, S. caucasicum and S. asperum differed from the other samples. All Symphytum species showed good antioxidant and enzyme inhibitory activities, as evaluated in DPPH (up to 50.17 mg Trolox equivalents (TE) g-1), ABTS (up to 49.92 mg TE g-1), cupric reducing antioxidant capacity (CUPRAC, up to 92.93 mg TE g-1), ferric reducing antioxidant power (FRAP, up to 53.63 mg TE g-1), acetylcholinesterase (AChE, up to 0.52 mg galanthamine equivalents (GALAE) g-1), butyrylcholinesterase (BChE, up to 0.96 mg GALAE g-1), tyrosinase (up to 13.58 mg kojic acid equivalents g-1) and glucosidase (up to 0.28 mmol acarbose equivalents g-1) tests. Pearson correlation analysis revealed potential links between danshensu and ABTS/FRAP/CUPRAC, quercetin-O-hexoside and DPPH/CUPRAC, or rabdosiin and anti-BChE activity.

CONCLUSIONS

By assessing for the first time in a comparative manner the phytochemical-biological profile of a considerably high number of Symphytum samples, this study unveils the potential use of less common comfrey species as novel phytopharmaceutical or agricultural raw materials. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Influence of pyrrolizidine alkaloids depletion upon the biological activity of Symphytum officinale L. extracts

ETHNOPHARMACOLOGICAL RELEVANCE

Comfrey (Symphytum officinale L., Boraginaceae) root preparations are used as both traditional remedies and therapeutic agents in treating pain and inflammation associated with joint, bone, and muscle ailments. Even though numerous phytochemicals contribute to the beneficial effects of comfrey, the presence of toxic pyrrolizidine alkaloids (PAs) overshadows its uses.

AIM OF THE STUDY

In this work, different PA-/mucilage-depleted/undepleted comfrey root extracts were subjected to detailed phytochemical characterization and biological evaluation.

MATERIALS AND METHODS

The phytochemical profiling was performed by LC-HRMS/MS. The quantification of PAs and major phenolic compounds was carried out by LC-MS/MS and LC-DAD. Antioxidant and enzyme inhibitory activity was determined by in vitro free radical scavenging, ion reducing, metal chelating, cholinesterase, tyrosinase, amylase, and glucosidase assays. Using an ex vivo model of LPS-stimulated neutrophils, their viability (as measured by flow cytometry) and the release of IL-1β, IL-8, and TNF-α were determined (ELISA assay).

RESULTS

12 phenolic acids, six PAs, three organic acids, two fatty acids, and two sugars were identified in the obtained comfrey extracts. The PA-depleted materials contained PAs levels below 2 ppm, whereas the removal of mucilage increased the content of rosmarinic acid, globoidnan A, globoidnan B, and rabdosiin. PA-depletion did not significantly affect the antioxidant potential. However, the radical scavenging and metal reducing properties were higher in the mucilage-depleted extracts. Neither PA-depletion nor mucilage-depletion had considerable effects on the in vitro inhibitory activity of cholinesterases, tyrosinase, amylase, and glucosidase or release of ex vivo pro-inflammatory cytokines (e.g., IL-1β, IL-8, and TNF-α) in LPS-stimulated neutrophils.

CONCLUSIONS

In light of their superior safety profiles, PA-depleted comfrey extracts can be utilized further in cosmetic and pharmaceutical products.

Metabolomics-Based Profiling via a Chemometric Approach to Investigate the Antidiabetic Property of Different Parts and Origins of Pistacia lentiscus L

Pistacia lentiscus L. is a medicinal plant that grows spontaneously throughout the Mediterranean basin and is traditionally used to treat diseases, including diabetes. The aim of this work consists of the evaluation of the α-glucosidase inhibitory effect (i.e., antidiabetic activity in vitro) of different extracts from the leaves, stem barks and fruits of P. lentiscus harvested on mountains and the littoral of Tizi-Ouzou in Algeria. Metabolomic profiling combined with a chemometric approach highlighted the variation of the antidiabetic properties of P. lentiscus according to the plant's part and origin. A multiblock OPLS analysis showed that the metabolites most involved in α-glucosidase inhibition activity were mainly found in the stem bark extracts. The highest inhibitory activity was found for the stem bark extracts, with averaged inhibition percentage values of 84.7% and 69.9% for the harvested samples from the littoral and mountain, respectively. On the other hand, the fruit extracts showed a lower effect (13.6%) at both locations. The UHPLC-ESI-HRMS characterization of the metabolites most likely responsible for the α-glucosidase-inhibitory activity allowed the identification of six compounds: epigallocatechin(4a>8)epigallocatechin (two isomers), (epi)gallocatechin-3'-O-galloyl-(epi)gallocatechin (two isomers), 3,5-O-digalloylquinic acid and dihydroxy benzoic acid pentoside.

In Vitro and In Silico Analysis of Bergenia ciliata and Mimosa pudica for Inhibition of α-Amylase

The discovery of antidiabetic natural products is a flourishing field of opportunity in the sector of drug discovery. Various medicinal plants with diverse chemical constituents have been extensively studied for drug development. Bergenia ciliata and Mimosa pudica have been traditionally used for the treatment of diabetes and consist of valuable phytochemicals. In this study, we have analyzed total phenolic and flavonoid content along with the antioxidant and α-amylase inhibitory activity. The crude extract of B. ciliata contains higher levels of TPC whereas higher TFC was observed in M. pudica. The strong antioxidant activity was shown by B. ciliata with an IC50 value of 125.86 ± 4.16 μg/mL. The ethyl acetate extract of B. ciliata and M. pudica showed higher α-amylase inhibitory activity with an IC50 value of 13.97 ± 0.10 and 11.97 ± 0.36 μg/mL, respectively. The biological potential of the reported phytochemicals was also assessed by using bioinformatic tools. Furthermore, the active phytochemicals from these plants were docked with human pancreatic α-amylase to study their inhibitory activities to this enzyme. The docking analysis revealed that catechin has lower binding energy (−8.6 kcal/mol) as compared to the commercial drug acarbose (−7.3 kcal/mol) indicating higher affinity towards the enzyme. This study additionally sheds more light on medicinal plants’ antidiabetic activity. So, this study will aid in the investigation of the biological properties of these plants as well as the identification of potential compounds with antidiabetic properties.

Anti-inflammatory Properties of the Genus Symphytum L.: A Review

: The Symphytum genus has been mainly used in traditional medicine, containing its anti-inflammatory activity. Symphytum spp.’s active components, such as allantoin, polyphenols, flavonoids, and alkaloids, can act on several intentions in the signaling pathway, constrain pro-inflammatory enzymes, reducing the construction of inflammatory chemokine’s and cytokines, and decreasing oxidative stress, which afterward suppresses inflammation procedures. Preclinical and clinical trials have reported the prevailing anti-inflammatory effect of several Symphytum species. This review presents an overview of the anti-inflammatory activities of different products and bioactive constituents in this genus. The papers with the English language were gathered from 2000 to 2021. This review may provide a scientific base for establishing innovative and alternative techniques for isolating a single individual from this genus to attenuate inflammatory disorders. The Symphytum genus is waiting for researchers to develop safe and effective anti-inflammatory agents for additional investigation of other different mechanisms of action.

Phytochemical Characterization and Evaluation of the Antioxidant and Anti-Enzymatic Activity of Five Common Spices: Focus on Their Essential Oils and Spent Material Extractives

The essential oil industry of aromatic herbs and spices is currently producing a significant amount of by-products, such as the spent plant materials remaining after steam or hydrodistillation, that are simply discarded. The aim of this study was to comparatively investigate the phytochemical composition, antioxidant and multi-enzymatic inhibitory potential of the essential oils and spent plant material extractives obtained from cinnamon, cumin, clove, laurel, and black pepper. The essential oils were characterized by the presence of several phytochemical markers (cinnamaldehyde, cuminaldehyde, eugenol, eucalyptol, α-terpinene, limonene, β-caryophyllene or β-pinene). On the other hand, the LC-HRMS/MS profiling of the spent material extracts allowed the annotation of species specific and non-specific metabolites, such as organic acids, phenolic acids, flavonoids, proanthocyanidins, hydrolysable tannins, fatty acids, or piperamides. All samples exhibited very strong antioxidant effects, with the clove essential oil displaying the strongest radical scavenging (525.78 and 936.44 mg TE/g in DPPH and ABTS assays), reducing (2848.28 and 1927.98 mg TE/g in CUPRAC and FRAP), and total antioxidant capacity (68.19 mmol TE/g). With respect to the anti-acetylcholinesterase (0.73-2.95 mg GALAE/g), anti-butyrylcholinesterase (0-3.41 mg GALAE/g), anti-tyrosinase (0-76.86 mg KAE/g), anti-amylase and anti-glucosidase (both 0-1.00 mmol ACAE/g) assays, the spice samples showed a modest activity. Overall, our study reports that, not only the volatile fractions of common spices, but also their spent plant materials remaining after hydrodistillation can be regarded as rich sources of bioactive molecules with antioxidant and multi-enzymatic inhibitory effects.

Insights into the Phytochemical and Multifunctional Biological Profile of Spices from the Genus Piper

Piper spices represent an inexhaustible reservoir of bioactive compounds that may act as drug leads in natural product research. The aim of this study was to investigate a series of methanolic fruit extracts obtained from P. nigrum (black, green, white and red), P. longum and P. retrofractum in comparative phytochemical and multi-directional biological (antimicrobial, antioxidant, anti-enzymatic and anti-melanogenic) assays. The metabolite profiling revealed the presence of 17 piperamides, with a total content of 247.75-591.42 mg piperine equivalents/g. Among the 22 tested microorganism strains, Piper spices were significantly active (MIC < 0.1 mg/mL) against the anaerobes Actinomyces israelii and Fusobacterium nucleatum. The antioxidant and anti-enzymatic activities were evidenced in DPPH (10.64-82.44 mg TE/g) and ABTS (14.20-77.60 mg TE/g) radical scavenging, CUPRAC (39.94-140.52 mg TE/g), FRAP (16.05-77.00 mg TE/g), chelating (0-34.80 mg EDTAE/g), anti-acetylcholinesterase (0-2.27 mg GALAE/g), anti-butyrylcholinesterase (0.60-3.11 mg GALAE/g), anti-amylase (0.62-1.11 mmol ACAE/g) and anti-glucosidase (0-1.22 mmol ACAE/g) assays. Several Piper extracts (10 μg/mL) inhibited both melanin synthesis (to 32.05-60.65% of αMSH+ cells) and release (38.06-45.78% of αMSH+ cells) in αMSH-stimulated B16F10 cells, partly explained by their tyrosinase inhibitory properties. Our study uncovers differences between Piper spices and sheds light on their potential use as nutraceuticals or cosmeceuticals for the management of different diseases linked to bacterial infections, Alzheimer's dementia, type 2 diabetes mellitus or hyperpigmentation.

Influence of the Post-Harvest Storage Time on the Multi-Biological Potential, Phenolic and Pyrrolizidine Alkaloid Content of Comfrey (Symphytum officinale L.) Roots Collected from Different European Regions

Comfrey (Symphytum officinale L.) roots are well-known bioactive ingredients included in various cosmeceutical and pharmaceutical preparations. In this study, the influence of the post-harvest storage on the chemico-biological potential of roots collected from different European regions and stored for up to six months was investigated. Total phenolic content (TPC) and total phenolic acid content (TPAC) were spectrophotometrically estimated, whereas the levels of individual phenolic and pyrrolizidine alkaloidal markers were determined by HPLC-DAD and HPLC-MS/MS, respectively. The changes in the biological potential was tracked via antioxidant (DPPH, ABTS, CUPRAC, and FRAP) and anti-enzymatic (cholinesterase, tyrosinase, glucosidase, and amylase) assays. TPC and TPAC varied from 6.48–16.57 mg GAE/g d.w. root and from 2.67–9.03 mg CAE/g, respectively. The concentration of the four phenolics (rosmarinic acid, globoidnan A, globoidnan B, rabdosiin) and six pyrrolizidine alkaloids generally showed maximum values at 1–3 months, after which their levels significantly decreased. With respect to the bioassays, the samples showed a wide range of antioxidant and anti-enzymatic effects; however, a direct storage time–bioactivity relationship was not observed. Similar conclusions were also revealed by the multivariate and correlation analyses. Our study could improve the current knowledge of the shelf-life properties of comfrey-based products and enhance their industrial exploitation.