Characterisation of Polyphenol-Containing Extracts from Stachys mucronata and Evaluation of Their Antiradical Activity

Phytochemical analysis, antioxidant and ALR2 inhibitory activity of Sorbus torminalis (L.) fruits at different maturity stages

Thirty four compounds were identified in Sorbus torminalis (L.) fruit extracts of different maturity types by means of LC-DAD-MS (ESI+) fragmentation analysis. Both immature and mature fruits were rich in flavonoid glycosides esterified with hydroxycinnamic, phenolic and dicarboxylic acids along with benzoic, phenylpropanoic and cinnamoyl quinic acid derivatives with many of them being detected for the first time in Sorbus species and in literature. Extracts and fractions were tested for their antioxidant activity (DPPH, chemiluminescence, Rancimat assays) and the estimation of the phenolic content was carried out through Folin-Ciocalteu reagent. Ethyl acetate fraction exhibited the highest scavenging activity determined as EC50 = 1.58 ± 0.22 μg/mL and EC50 = 1.64 ± 0.24 μg/mL for immature and mature fruits respectively with the DPPH test. Chemiluminescence test indicated the same fraction having the strongest antioxidant activity with an IC50 0.41 ± 0.06 μg/mL and IC50 0.50 ± 0.02 μg/mL in both maturity types. The ethyl acetate fraction of the mature fruits is considered the most potent Aldose Reductase 2 (ALR2) inhibitor with 79% demonstrating the high nutritional value of Sorbus torminalis (L.) mature fruits as a defense mechanism against the onset of diabetes mellitus secondary complications leading to the utilization of the plant for nutritional and pharmaceutical purposes.

Photoprotection and Antiaging Activity of Extracts from Honeybush (Cyclopia sp.)-In Vitro Wound Healing and Inhibition of the Skin Extracellular Matrix Enzymes: Tyrosinase, Collagenase, Elastase and Hyaluronidase

Cyclopia sp. (honeybush) is an African shrub known as a rich source of polyphenols. The biological effects of fermented honeybush extracts were investigated. The influence of honeybush extracts on extracellular matrix (ECM) enzymes responsible for the skin malfunction and aging process-collagenase, elastase, tyrosinase and hyaluronidase-was analysed. The research also included assessment of the in vitro photoprotection efficiency of honeybush extracts and their contribution to the wound healing process. Antioxidant properties of the prepared extracts were evaluated, and quantification of the main compounds in the extracts was achieved. The research showed that the analysed extracts had a significant ability to inhibit collagenase, tyrosinase and hyaluronidase and a weak influence on elastase activity. Tyrosinase was inhibited effectively by honeybush acetone (IC₅₀ 26.18 ± 1.45 µg/mL), ethanol (IC₅₀ 45.99 ± 0.76 µg/mL) and water (IC₅₀ 67.42 ± 1.75 µg/mL) extracts. Significant hyaluronidase inhibition was observed for ethanol, acetone and water extracts (IC₅₀ were 10.99 ± 1.56, 13.21 ± 0.39 and 14.62 ± 0.21µg/mL, respectively). Collagenase activity was inhibited effectively by honeybush acetone extract (IC₅₀ 42.5 ± 1.05 μg/mL). The wound healing properties of the honeybush extracts, estimated in vitro in human keratinocytes (HaCaTs), were indicated for water and ethanol extracts. In vitro sun protection factor (SPF in vitro) showed medium photoprotection potential for all the honeybush extracts. The quantity of polyphenolic compounds was estimated with the use of high-performance liquid chromatography equipped with diode-array detection (HPLC-DAD), indicating the highest mangiferin contents in ethanol, acetone and n-butanol extracts, while in the water extract hesperidin was the dominant compound. The antioxidant properties of the honeybush extracts were estimated with FRAP (2,4,6-Tris(2-pyridyl)-s-triazine) and DPPH (2,2-diphenyl-1-picrylhydrazyl) tests, indicating their strong antioxidant activity, similar to ascorbic acid for the acetone extract in both tests. The wound healing abilities, estimation of SPF in vitro and the direct influence on selected enzymes (elastase, tyrosinase, collagenase and hyaluronidase) of the tested honeybush extracts were analysed for the first time, indicating a high potential of these well-known herbal tea for antiaging, anti-inflammation, regeneration and protection of the skin.

Evaluation of Phenolic Content Diversity along with Antioxidant/Pro-Oxidant, Glutathione Transferase Inhibition, and Cytotoxic Potential of Selected Commonly Used Plants

The function of antioxidant polyphenols has been demonstrated for their ability to protect against a variety of diseases. However, some antioxidants have been shown to be pro-oxidant. Some of the important antioxidant enzymes are glutathione transferases (GST), which are involved in maintaining redox homeostasis. GST class Pi (GSTP1-1) hyper-activation is a feature that is found in cancer. This work aims to demonstrate the relationship between the phytochemicals of 18 plants and their ability to act as antioxidant/pro-oxidant agents, as well as their effects on the activity of GSTP1-1 and their cellular toxicity. Tamarindus indica, Cinnamomum verum, and Alpinia galanga extracts had high phytochemical contents, moderate heavy metal levels, and antioxidant/pro-oxidant activities. Among the main plant components identified using high-performance liquid chromatography, only chlorogenic acid, catechin, and quercetin can function as antioxidants and pro-oxidants. Hibiscus sabdariffa, C. verum, A. galanga, T. indica, Gossypium arboreum, and Punica granatum were among the plant extracts examined that inhibited the activity of the purified recombinant GSTP1-1, with the inhibition constant values ranging from 0.48 to 1.67 mg of gallic acid equivalent/g. The level of cytotoxicity was also studied to determine the effects of these extracts on human Caucasian breast cancer. The findings revealed that plants with high phenol content had an antioxidant/pro-oxidant capacity as well as inhibition of the activity of GST. However, the cytotoxic effect was not associated with all of the extracts, which indicates that polyphenols interact with other components that may influence their observed behavior.

Untargeted metabolomics study and identification of potential biomarkers in the six sections of the genus Stachys L. (Lamiaceae) using HPLC-MQ-API-MS/MS

INTRODUCTION

The genus Stachys L., belonging to the family Lamiaceae, is one of the largest genera with remarkable medicinal properties. Plants of this genus produce a broad range of secondary metabolites.

OBJECTIVES

Due to the incomplete comprehensive assessment of chemical profiles in Stachys species, we conducted an untargeted metabolomics study and identified potential biomarkers in the six sections of Stachys with chemotaxonomic importance.

MATERIAL AND METHODS

Dried leaves of 17 taxa were utilized for analysis of all the constituents using HPLC-MQ-API-MS. The obtained data were processed and analyzed using multivariate statistical methods, including heatmaps, PLS-DA score plots, functional analysis of metabolic pathways, metabolite set enrichment analysis, and biomarker and network analysis.

RESULTS

Among the 129 metabolites, 111 flavonoids and 18 non-flavonoids were recognized. The most represented flavonoids, including 41 flavones and 20 flavonols, displayed remarkable abundance. In non-flavonoid compounds, a total of six coumarins and six phenolic acids were present at high levels. In terms of approved markers in six sections, 76 chemical compounds, mainly flavonoids, coumarins, quinic acids, and cinnamic acids, were identified as potential biomarkers or chemotaxonomic indicators. Accordingly, the taxonomic complexities of some Stachys species in sections Fragilicaulis, Aucheriana, and Setifolia were properly resolved.

CONCLUSION

An HPLC-MS/MS-based metabolomics approach integrated with multivariate statistical methods was employed to identify (1) valuable markers and analyze metabolic diversity and (2) predict the pharmaceutical properties of Stachys species. The obtained chemical profiles provide a new perspective for investigation of the Stachys genus.

Biological Activity and NMR-Fingerprinting of Balkan Endemic Species Stachys thracica Davidov

Stachys thracica Davidov is a Balkan endemic species distributed in Bulgaria, Greece, and Turkey. In Bulgaria, it is classified as “rare” and is under the protection of the Bulgarian biodiversity law. The aim of our study was to develop an efficient protocol for ex situ conservation of S. thracica and to perform comparative NMR-based metabolite profiling and bioactivity assays of extracts from in situ grown, in vitro cultivated, and ex vitro acclimated plants. Micropropagation of S. thracica was achieved by in vitro cultivation of mono-nodal segments on basal MS medium. Ex vitro adaptation was accomplished in the experimental field with 83% survival while conserved genetic identity between in vitro and ex vitro plants as shown by the overall sequence-related amplified polymorphism marker patterns was established. Verbascoside, chlorogenic acid, and trigonelline appeared the main secondary metabolites in in situ, in vitro cultivated, and ex vitro acclimated S. thracica. High total phenolic and flavonoid content as well as antioxidant and radical scavenging activity were observed in in situ and ex vitro plants. Further, the anti-inflammatory activity of S. thracica was tested by hemolytic assay and a high inhibition of the complement system was observed. Initiated in vitro and ex vitro cultures offer an effective tool for the management and better exploitation of the Stachys secondary metabolism and the selection of lines with high content of bioactive molecules and nutraceuticals.

Genus Stachys: A Review of Traditional Uses, Phytochemistry and Bioactivity

The present review highlights that Stachys spp. consist an important source of bioactive phytochemicals and exemplifies the uncharted territory of this genus for new research studies.

Polyphenols as Caloric-Restriction Mimetics and Autophagy Inducers in Aging Research

It has been thought that caloric restriction favors longevity and healthy aging where autophagy plays a vital role. However, autophagy decreases during aging and that can lead to the development of aging-associated diseases such as cancer, diabetes, neurodegeneration, etc. It was shown that autophagy can be induced by mechanical or chemical stress. In this regard, various pharmacological compounds were proposed, including natural polyphenols. Apart from the ability to induce autophagy, polyphenols, such as resveratrol, are capable of modulating the expression of pro- and anti-apoptotic factors, neutralizing free radical species, affecting mitochondrial functions, chelating redox-active transition metal ions, and preventing protein aggregation. Moreover, polyphenols have advantages compared to chemical inducers of autophagy due to their intrinsic natural bio-compatibility and safety. In this context, polyphenols can be considered as a potential therapeutic tool for healthy aging either as a part of a diet or as separate compounds (supplements). This review discusses the epigenetic aspect and the underlying molecular mechanism of polyphenols as an anti-aging remedy. In addition, the recent advances of studies on NAD-dependent deacetylase sirtuin-1 (SIRT1) regulation of autophagy, the role of senescence-associated secretory phenotype (SASP) in cells senescence and their regulation by polyphenols have been highlighted as well. Apart from that, the review also revised the latest information on how polyphenols can help to improve mitochondrial function and modulate apoptosis (programmed cell death).