Phenolic compounds of Sideritis ozturkii and their in vivo anti-inflammatory and antinociceptive activities

Exploring the anti-inflammatory, sedative, antidiabetic, and antioxidant potential in in-vitro and in-vivo models and phenolic profiling of Atractylis aristata Batt

ETHNOPHARMACOLOGICAL RELEVANCE

Atractylis aristata batt., as an endemic plant from the Asteraceae family, holds a significant position in the Ahaggar region of southern Algeria's traditional medicine. The aerial parts of Atractylis aristata was used to cure inflammation, fever, and stomach disorders.

AIM OF THE STUDY

The objective of the present investigation was to ascertain the overall bioactive components and phytochemical components and examine the antioxidant, antidiabetic, anti-inflammatory, acute toxicity, and sedative properties of the crude extract obtained from the aerial portions of Atractylis aristata (AaME).

MATERIALS AND METHODS

The AaME's antioxidant activity was assessed by the use of pyrogallol autoxidation, (1,1 diphenyl-2-picrylhydrazyl) (DPPH), 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and reducing power (RP) techniques. 1 mg/mL of AaME was used to evaluate the antidiabetic activity by applying the enzyme α-amylase inhibitory power test. At the same time, the bovine serum albumin (BSA) denaturation method was employed to quantify the in vitro anti-inflammatory activity at different concentrations (1.5625, 0.78125, 0.390625, 0.1953125 and 0.09765625 mg/mL). In contrast, following the Organization for Economic Co-operation and Development (OECD) guideline No. 423, which covers acute oral toxicity testing protocols, the limit dosage test was employed to assess in vivo acute toxicity. At the dose of 0.08 mg/mL, the carrageenan-induced paw edema approach was used to assess the anti-inflammatory efficacy in vivo, and the sedative activity was carried out at the dose of 0.08 mg/mL using the measurement of the locomotor method. Different bioactive compounds were identified within AaME using LC-MS/MS and HPLC-UV analysis.

RESULTS

The acute toxicity study showed no fatalities or noticeable neurobehavioral consequences at the limit test; this led to their classification in Globally Harmonized System (GHS) category Five, as the OECD guideline No 423 recommended. At a concentration of 0.08 mg/mL (2000 mg/kg), AaME showed apparent inhibition of paw edema and a significant (p = 0.01227) reduction in locomotor activity compared to the control animals. Our findings showed that AaME exhibited considerable antioxidant (IC50 = 0.040 ± 0.003 mg/mL (DPPH), IC50 = 0.005 ± 5.77 × 10-5 mg/mL (ABTS), AEAC = 91.15 ± 3.921 mg (RP) and IR% = 23.81 ± 4.276 (Inhibition rate of pyrogallol) and rebuts antidiabetic activities (I% = 57.6241% ± 2.81772). Our findings revealed that the maximum percentage of BSA inhibition (70.84 ± 0.10%) was obtained at 1.562.5 mg/mL. Thus, the AaME phytochemical profile performed using phytochemical screening, HPLC-UV, and LC-MS/MS analysis demonstrated that A. aristata can be a valuable source of chemicals with biological activity for pharmaceutical manufacturers.

CONCLUSION

The phytochemical profiling, determined through HPLC-UV and LC-MS/MS applications, reveals this plant's therapeutic value. The aerial parts of Atractylis aristata contain bioactive molecules such as gallic acid, ascorbic acid, and quercetin, contributing to its significant antioxidant capabilities. Furthermore, identifying alizarin, the active compound responsible for its anti-inflammatory properties, could provide evidence supporting the anti-inflammatory capabilities of this subspecies.

Addressing astringency of grape seed extract by covalent conjugation with lupin protein

Astringency of phenolic-rich foods is a key tactile perception responsible for acceptability/rejection of plant extracts as ingredients in formulations. Covalent conjugation of phenolic extracts with plant proteins might be a promising strategy to control astringency, but suffers from a lack of mechanistic understanding from the lubrication point of view. To shed light on this, this ex vivo study evaluated the effect of conjugation of a phenolic grape seed extract (GSE) with legume protein (lupin, LP) on tribological and surface adsorption performance of GSE in the absence and presence of human saliva (ex vivo). Tribological results confirmed GSE had an inferior lubrication capacity as compared to LP. The lubrication performance of LP-GSE dispersions was comparable to their corresponding LP dispersion (p > 0.05) when covalently conjugated with LP (LP-GSE) with increasing LP:GSE ratio up to 1:0.04 w/w and at a specific degree of conjugation (DC: 2%). Tribological and surface adsorption measurements confirmed the tendency of GSE to interact with human saliva (ex vivo, n = 17 subjects), impairing the lubricity of salivary films. The covalent bonding of LP to GSE hindered GSE's interaction with human saliva, implying the potential influence of covalent conjugation on attenuating astringency. LP appeared to compete with human saliva for surface adsorption and governed the lubrication behaviour in LP-GSE dispersions. Findings from this study provide valuable knowledge to guide the rational design of sustainable, functional foods using conjugation of phenolics with plant proteins to incorporate larger proportions of health-promoting phenolics while controlling astringency, which needs validation by sensory trials.

Chemical profile of the Anatolian Sideritis species with bioactivity studies

CONTEXT

The genus Sideritis L. (Lamiaceae) is represented by 46 species in Turkey with an 79% endemism ratio, 42 of 46 belonging to the section Empodoclia.

OBJECTIVE

In this review article, Sideritis species growing in Turkey have been evaluated for phytochemical constituents and biological activities.

METHODS

The data for the isolates, components and extracts of the Anatolian Sideritis species and their bioactivity studies were retrieved from the main databases WoS, Scopus and PubMed from 1975 until 31 December 2022.

RESULTS

In this review article, terpenoids, flavonoids, phenolics and other secondary metabolites isolated from Turkish Sideritis species were reported. Anatolian Sideritis species, which primarily consist of monoterpenes and sesquiterpenes, were studied in detail. Sideritis plants are represented by 46 species in Turkey, and 25 of them were investigated for their diterpenoids through isolation or LC-MS studies. Most of the diterpenoids of Turkish Sideritis species have ent-kaurene skeleton, among them linearol, siderol, 7-epicandicandiol and sideridiol were found to be the main compounds. Exceptionally, labdane, pimarane and beyerene diterpenoids were only found in a few species. For phenolics and flavonoids, only 12 species were investigated until now, and they were found to be rich in phenylethanoid glycosides and flavonoid glycosides. In terms of activity, most of the species were tested for antioxidant activity, followed by antimicrobial and anti-ulcer/anti-inflammatory activities. Their cytotoxic, enzyme inhibitory, antinociceptive and antistress activities were less frequently studied.

CONCLUSIONS

Sideritis species should be considered promising therapeutic agents in the treatment of upper respiratory tract and ulcer/inflammatory diseases.

Endemic Mountain Tea (Sideritis dichotoma Huter): Antioxidant and Antibacterial Activities, Mineral Content by ICP-MS and Phytochemical Content by LCHR-MS

Endemic Sideritis dichotoma Huter, herbal tea, is used for colds, coughs and digestive ailments. Since at least 25 % of the active ingredients of pharmacological drugs are obtained from plants, it is important to investigate many plants, both traditionally used and whose potential hasnt yet been discovered, before they disappear. When the results compared to other Sideritis species, it has better antioxidant activity in DPPH⋅ scavenging activity, Fe3+ and Cu2+ reducing capacity methods and is also rich in minerals, necessary for human body, K, Mg, Ca, P, S. Zone values (10-19,5 mm) obtained on S. aureus, P. aeruginosa, E. coli, S.enteritidis, E. faecalis, P. putida and K. pnemoniae strains are an indication that the plant has antibacterial activity. 27 secondary metabolites were identified by LC-HRMS. Verbascoside, pharmacologically active compound known to have antitumor effect, cytotoxic selectivity and anticancer activity, is the most abundant phenolic in ethanol extract (49297.13 mg/kg).

Natural acylated flavonoids: their chemistry and biological merits in context to molecular docking studies

Acylated flavonoids are widely distributed natural dietary bioactives with several health attributes. A large diversity of acylated flavonoids with interesting biological potentialities were reported. Of these, 123 compounds with potential antimicrobial, antiparasitic, anti-inflammatory, anti-nociceptive, analgesic and anti-complementary effects were selected from several databases. Based upon these data, the possible mechanistic evidence for their effects were reported. Generally, aromatic acyls i.e., galloyl derivatives appeared to improve efficacy through enhancement of the binding affinities to molecular targets due to plenty of donating and accepting centers. Docking simulations conducted by Molecular Operating Environment (MOE) of acylated flavonoids revealed that compound 12 is at the top of the list into the antibacterial target DNA gyrase subunit B (GyrB), from E. coli, followed by compounds 10, 4 and 23. Compounds 81, 88, 96, 92, 99, 100, 102 and 103 have the strongest binding affinities into Human matrix metallopeptidase (MMP) 2 and 9 catalytic domains. Compound 103 exerted the most balanced predicted dual MMP-2/MMP-9 inhibition action. Compound 95 recorded the strongest binding affinity into metabotropic glutamate receptor (mglur1) with the lowest energy conformer. The data presented in this review suggests that these candidate acylated flavonoids ought to be considered in future drug developments especially as anti-inflammatory and antimicrobial agents.

Phytochemical Analysis, Antioxidant and Anticancer Potential of Sideritis niveotomentosa: Endemic Wild Species of Turkey

Sideritis niveotomentosa Hub. -Mor. is a local endemic species belonging to the Lamiaceae family. In this study, GC/MS analysis, total antioxidant capacity and anticancer effects of different extracts obtained from S. niveotomentosa were investigated comparatively. Total phenolic contents of extracts were determined by the Folin–Ciocalteu method, total flavonoid contents by aluminum chloride method, and also the free radical scavenging activities of the extracts by DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) assay. The cytotoxic effect of the extracts was studied via MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) assay on DLD1, HL60 and ARH77 cell lines. Pro-apoptotic gene expression levels were also tested in the most sensitive cell line ARH77 by Real-Time PCR. The expression levels of 4 pro-apoptotic genes, APAF, BAX, CASP3, and HRK were found to be upregulated in ARH77 cells that were treated extracts. Results showed that methanolic extracts contain more phenolic content than acetone extracts, consistent with DPPH results. As a result, Sideritis niveotomentosa extracts, especially methanolic extracts, are rich in phenolic content and have a strong radical scavenging effect. In addition, the extracts showed selective effects on cell lines. This study is pioneering in terms of future studies, and the findings provide hope for future experimentation.

Genus Sideritis, section Empedoclia in southeastern Europe and Turkey - studies in ethnopharmacology and recent progress of biological activities

BACKGROUND

Over the last two decades there has been a substantial increase of the number of studies on the species of genus Sideritis. Species of section Empedoclia, occurring in the Eastern Mediterranean region and in part of Western Asia possess some remarkable characteristics and are known as valuable medicinal plants used by local people in the traditional medicine and for herbal tea. The objective of the review is to make a survey on the recent studies on the ethnopharmacology and biological activity of the species in Southeastern Europe and in Turkey, which is the center of distribution and their main occurrence.

MAIN BODY

The review focuses on the ethnopharmacology and biological activities of the species of interest. The survey revealed that a total of 47 species belonging to section Empedoclia have been studied either in ethnopharmacological aspect, or in relation to their biological activities, or both. Most species have been used traditionally by the local people as herbal tea or for treatment of various health problems, most frequently flu, cold and respiratory diseases. Sideritis species demonstrate numerous biological activities and are promising for use in the therapy of many diseases and health disorders. Antioxidant activity was found in 40 species, antimicrobial and antibacterial activity - in 27 species, anti-inflammatory - in 14 species, antifungal - in 8 species, cytotoxic - in 7 species. There were also some other, more specific biological activities, found in a few species, but considered promising for further studies and application.

SHORT CONCLUSION

The species of genus Sideritis, section Empedoclia have been used by local people as herbal tea and in traditional medicine since long time ago. People are taking advantage of the high species diversity and are aware of their useful properties. Much more information is available on the biological activities of the target species than on their traditional uses. Most species demonstrate various biological activities and are of substantial interest for further studies on their pharmacological properties and their potential for pharmacy and medicine. Graphical abstract Schematic illustration of traditional uses and biological activities of some Sideritis species. Arrows with different colors represent biological activities of different species. The species and their corresponding color can be seen at the right part of the figure. The colors correspond also to the squares placed in the different parts of human body.

Chemical and Antimicrobial Analyses of Sideritis romana L. subsp. purpurea (Tal. ex Benth.) Heywood, an Endemic of the Western Balkan

A comprehensive study on essential oil and different solvent extracts of Sideritis romana L. subsp. purpurea (Tal. ex Benth.) Heywood (Lamiaceae) from Montenegro is reported. The gas chromatography-mass spectrometry analysis of the essential oil revealed a total of 43 components with bicyclogermacrene (23.8%), germacrene D (8%), (E)-caryophyllene (7.9%) and spathulenol (5.5%) as the major ones. Sesquiterpenoid group was found to be the most dominant one (64.8%), with 19.9% of the oxygenated forms. In the crude methanol extract of the investigated plant, obtained by Sohhlet exraction, the total phenol content was 14.7 ± 0.4 mg of GA/g, the total flavonoids were 0.29 ± 0.03% expressed as hyperoside percentage, whereas the total tannins content was 0.22 ± 0.04% expressed as pyrogallol percentage. For the antimicrobial activity determination, the following microorganisms have been used: methicillin-susceptible Staphylococcus aureus (MSSA (American Type Culture Collection (ATCC) 29213)) and methicillin-resistant S. aureus (MRSA (clinical strain)), Escherichia coli (ATCC 25922), carbapenem-susceptible Klebsiella pneumoniae (clinical strain), carbapenem-resistant K. pneumoniae (clinical strain) and Candida albicans (ATCC 14053). The essential oil showed high potency against MSSA and MRSA, both at high (~5 × 10⁵ CFU/mL) and low (~5 × 10³ CFU/mL) inoculum. With respect to MSSA, the minimal inhibitory concentration (MIC) value was 0.307 mg/mL, with bactericidal activity obtained at 0.615 mg/mL, while, in the case of MRSA, the MIC and minimal bactericidal concentration (MBC) values were 0.076 and 0.153 mg/mL, respectively. Regarding anti-Candida albicans activity, the MIC value was 2.46 mg/mL without reaching fungicidal activity. In addition to the observed essential oil efficacy, different solvent extracts were analyzed for their antimicrobial activity. Similarly to the essential oil, thehighest efficacy was observed against both MSSA and MRSA strains, at high and low inoculums, in the case of the 1,2-dichloroethane and methanol extracts. A potent fungicidal activity has been also found for the n-hexane and 1,2-dichloroethane extracts. It can be concluded that Sideritis romana L. subsp. purpurea (Tal. ex Benth.) Heywood provides a wide range of application in different fields such as phytochemistry, pharmacology, toxicology or pharmacognosy.

Antioxidant Activity and Chemical Composition of Essential Oils of some Aromatic and Medicinal Plants from Albania

The chemical compositions have been investigated of the volatile oils of nine populations of six species from Albania, namely Artemisia absinthium, Calamintha nepeta, Hypericum perforatum, Sideritis raeseri subsp. raeseri, Origanum vulgare subsp. hirtum from two wild populations, and Salvia officinalis (sage) from two wild and one cultivated population,. The essential oils were obtained by hydrodistillation and their analyses were performed by GC–MS. The major constituents were: A. absinthium: neryl isovalerate (19.5%), geranyl isobutanoate (16.4%) and carvacrol (8.8%); C. nepeta: pulegone (31.7%), spathulenol (20.0%) and isomenthone (12.7%); H. perforatum: caryophyllene oxide (31.0%), δ-selinene (10.5%) and carvacrol (10.4%); O. vulgare: carvacrol (81.0, 78.6%), γ-terpinene (5.5, 7.1%) and p-cymene (4.9, 4.1%) for O. vulgare originating from Tepelena and Vlora, respectively; S. raeseri: carvacrol (36.7%), caryophyllene oxide (17.8%), β-caryphyllene (8.7%), spathulenol (7.7%) and myrtenol (6.4%); S. officinalis: camphor (40.2, 47.8, 45.9%), α-thujone (19.2, 22.2, 13.7%), eucalyptol (5.4, 2.6, 6.0%), camphene (5.8, 6.1, 3.9, %), borneol (2.1, 2.9, 5.7%) and bornyl acetate (3.3, 1.4, 5.6%) for samples originating from Tepelena, Tirana and Vlora, respectively. The essential oils were also tested for their free radical scavenging activity using the following in vitro assays: i) interaction with the free stable radical of DPPH (1,1-diphenyl-2-picrylhydrazyl), and ii) inhibition of linoleic acid peroxidation with 2,2'-azobis-2-methyl-propanimidamide, dihydrochloride (AAPH). Finally, their inhibitory activity toward soybean lipoxygenase was evaluated, using linoleic acid as substrate. The essential oil of O. vulgare (OV-VL) presented the highest interaction with the stable radical DPPH (76.5%), followed by that of A. absinthium (54.7%). O. vulgare (OV-TP) and A. absinthium showed high anti-lipid peroxidation activity, 97.5% and 96.5%, respectively, higher than that of the reference compound trolox (73.0%). Only the tested sample of O. vulgare (OV-VL) significantly inhibited soybean lipoxygenase (54.2%).

Flavonoids from Sideritis Species: Human Monoamine Oxidase (hMAO) Inhibitory Activities, Molecular Docking Studies and Crystal Structure of Xanthomicrol

The inhibitory effects of flavonoids on monoamine oxidases (MAOs) have attracted great interest since alterations in monoaminergic transmission are reported to be related to neurodegenerative diseases such as Parkinson's and Alzheimer's diseases and psychiatric disorders such as depression and anxiety, thus MAOs may be considered as targets for the treatment of these multi-factorial diseases. In the present study, four Sideritis flavonoids, xanthomicrol (1), isoscutellarein 7-O-[6'''-O-acetyl-β-D-allopyranosyl-(1→2)]-β-D-glucopyranoside (2), isoscutellarein 7-O-[6'''-O-acetyl-β-D-allopyranosyl-(1→2)]-6''-O-acetyl-β-D-glucopyranoside (3) and salvigenin (4) were docked computationally into the active site of the human monoamine oxidase isoforms (hMAO-A and hMAO-B) and were also investigated for their hMAO inhibitory potencies using recombinant hMAO isoenzymes. The flavonoids inhibited hMAO-A selectively and reversibly in a competitive mode. Salvigenin (4) was found to be the most potent hMAO-A inhibitor, while xanthomicrol (1) appeared as the most selective hMAO-A inhibitor. The computationally obtained results were in good agreement with the corresponding experimental values. In addition, the x-ray structure of xanthomicrol (1) has been shown. The current work warrants further preclinical studies to assess the potential of xanthomicrol (1) and salvigenin (4) as new selective and reversible hMAO-A inhibitors for the treatment of depression and anxiety.

Dual Excitatory and Smooth Muscle-relaxing Effect of Sideritis montana Extract on Guinea-pig Ileum

The neuronal and smooth muscle effects of a methanol extract prepared from the air-dried flowering aerial parts of Sideritis montana L. (SME) was tested in vitro on Guinea-pig ileum. The chemical composition of the investigated extract was analysed by HPLC-MS, and chrysoeriol, chlorogenic acid and caffeic acid were detected as main constituents. The isolated organ assay showed that S. montana extract caused an immediate contraction and a more slowly developing inhibitory response in the ileum. The SME-induced contractions were strongly inhibited by the acetylcholine muscarinic receptor antagonist atropine (0.5 μM), but not by either the Na+ channel blocker tetrodotoxin (TTX; 0.5 μM) or the histamine H1 receptor antagonist chloropyramine (0.5 μM). Selective desensitization of capsaicin-sensitive neurons by the sensory neuron stimulant and blocker capsaicin did not influence the contractile effect of SME. As to the spasmolytic effect, SME inhibited the effects of electrical field stimulation, exogenous acetylcholine, and histamine. These smooth muscle-relaxing effects were reversible in 40 min by repeated renewals of the bathing solution.

Second-order data obtained by beta-cyclodextrin complexes: a novel approach for multicomponent analysis with three-way multivariate calibration methods

This research reports the first application of β-cyclodextrin (β-CD) complexes as a new method for generation of three way data, combined with second-order calibration methods for quantification of a binary mixture of caffeic (CA) and vanillic (VA) acids, as model compounds in fruit juices samples. At first, the basic experimental parameters affecting the formation of inclusion complexes between target analytes and β-CD were investigated and optimized. Then under the optimum conditions, parallel factor analysis (PARAFAC) and bilinear least squares/residual bilinearization (BLLS/RBL) were applied for deconvolution of trilinear data to get spectral and concentration profiles of CA and VA as a function of β-CD concentrations. Due to severe concentration profile overlapping between CA and VA in β-CD concentration dimension, PARAFAC could not be successfully applied to the studied samples. So, BLLS/RBL performed better than PARAFAC. The resolution of the model compounds was possible due to differences in the spectral absorbance changes of the β-CD complexes signals of the investigated analytes, opening a new approach for second-order data generation. The proposed method was validated by comparison with a reference method based on high-performance liquid chromatography photodiode array detection (HPLC-PDA), and no significant differences were found between the reference values and the ones obtained with the proposed method. Such a chemometrics-based protocol may be a very promising tool for more analytical applications in real samples monitoring, due to its advantages of simplicity, rapidity, accuracy, sufficient spectral resolution and concentration prediction even in the presence of unknown interferents.

Antinociceptive effect and gastroprotective mechanisms of 3,5-diprenyl-4-hydroxyacetophenone from Ageratina pichinchensis

The present study aimed to evaluate the antinociceptive activity (in inflammatory and neuropathic pain models) and gastroprotective effect of the 3,5-diprenyl-4-hydroxyacetophenone (HYDP), isolated from Ageratina pichinchensis. The gastroprotective activity of this plant was previously reported by our workgroup, finding encesanescin to be one active compound. The present results show that HYDP reduced nociception in a dose-dependent manner in carrageenan and L5/L6 spinal nerve ligation, with efficacies of 72.6 and 57.1%, respectively, at doses of 100 and 562 mg/kg. HYDP also showed gastroprotective activity in the model of ethanol-induced gastric lesion, with a 75.59% maximum inhibition of ulcers at a dose of 100mg/kg. This gastroprotective effect was attenuated by N(G)-nitro-L-arginine methyl ester, indomethacin and N-ethylmaleimide, indicating that NO, prostaglandins and sulfhydryl groups are involved in the mechanisms of action. This is the first evidence, to our knowledge, of the antinociceptive and gastroprotective activities of HYDP.

Chemical and antimicrobial evaluation of supercritical and conventional Sideritis scardica Griseb., Lamiaceae extracts

Sideritis scardica Griseb., Lamiaceae (ironwort, mountain tea), an endemic plant of the Balkan Peninsula, has been used in traditional medicine in the treatment of antimicrobial infections, gastrointestinal complaints, inflammation and rheumatic disorders. This study reports a comparison between conventional (hydrodistillation HD and solvent extraction SE) and alternative (supercritical carbon dioxide SC CO₂) extraction methods regarding the qualitative and quantitative composition of the obtained extracts as analyzed by GC and GC-MS techniques and their anitimicrobial activity. Different types of extracts were tested, the essential oil EO obtained by HD, EO-CO₂ and AO-CO₂ obtained by SC CO₂ at different preasures 10 and 30 MPa, at 40 °C, respectively, and the fractions A, B, C and D obtained by successive solvent extraction (SE) A: ethanol, B: diethyl ether, C: ethyl acetate and D: n-butanol). While EO was characterized by the presence of the high percentage of oxygenated monoterpenes and sesquiterpenes (30.01 and 25.54%, respectively), the rest of the investigated samples were the most abundant in fatty acids and their esters and diterpenes (from 16.72 to 71.07% for fatty acids and their esters, and from 23.30 to 72.76%, for diterpenes). Microbial susceptibility tests revealed the strong to moderate activity of all investigated extracts against the tested microorganisms (MIC from 40 to 2,560 μg/mL). Although differences in the chemical compositions determined by GC and GC-MS analysis were established, the displayed antimicrobial activity was similar for the all investigated extracts.

Phytochemical composition of "mountain tea" from Sideritis clandestina subsp. clandestina and evaluation of its behavioral and oxidant/antioxidant effects on adult mice

PURPOSE

The goals of this study were to monitor the effect of drinking of herbal tea from Sideritis clandestina subsp. clandestina for 6 weeks on behavioral and oxidant/antioxidant parameters of adult male mice and also to evaluate its phytochemical composition.

METHODS

The phytochemical profile of the Sideritis tea was determined by liquid chromatography-UV diode array coupled to ion-trap mass spectrometry with electrospray ionization interface. The effects of two doses of the herbal infusion (2 and 4% w/v, daily) intake on anxiety-like state in mice were studied by the assessment of their thigmotactic behavior. The oxidant/antioxidant status of brain (-Ce), liver and heart of adult male Balb-c mice following the consumption of Sideritis tea was also evaluated via the measurement of malondialdehyde (MDA) and reduced glutathione (GSH) levels using fluorometric assays. Our study was further extended to determine the antioxidant effects of the herbal tea on specific brain regions (cerebral cortex, cerebellum and midbrain).

RESULTS

The identified compounds were classified into several natural product classes: quinic acid derivatives, iridoids, phenylethanol glycosides and flavonoids. Our results showed that only the 4% Sideritis tea exhibited anxiolytic-like properties as evidenced by statistically significant (p < 0.05) decrease in the thigmotaxis time and increase in the number of entries to the central zone in comparison with the control group. Consumption of both tea doses (2 and 4% w/v) elevated GSH (12 and 28%, respectively, p < 0.05) and decreased MDA (16 and 29%, p < 0.05) levels in brain (-Ce), while liver and heart remained unaffected. In regard to the effect of herbal tea drinking (2 and 4% w/v) on specific brain regions, it caused a significant increase in GSH of cerebellum (13 and 36%, respectively, p < 0.05) and midbrain (17 and 36%, p < 0.05). Similarly, MDA levels were decreased in cerebellum (45 and 79%, respectively, p < 0.05) and midbrain (50 and 63%, respectively, p < 0.05), whereas cerebral cortex remained unaffected.

CONCLUSIONS

Mountain tea drinking prevents anxiety-related behaviors and confers antioxidant protection to rodent's tissues in a region-specific, dose-dependent manner, and its phytochemical constituents are shown for the first time.

Protective effect of Sideritis euboea extract on bone mineral density and strength of ovariectomized rats

OBJECTIVE

The aim of this study was to investigate the potential protective effect of Sideritis euboea extract (SID), commonly consumed as "mountain tea," on bone mineral density (BMD) and the strength of the ovariectomized (OVX) rat model of osteoporosis.

METHODS

Thirty-two 10-month-old Wistar rats were separated into controls (sham operated), OVX, and OVX plus SID in their drinking water (dose, 330 mg/kg body weight per day), starting immediately after OVX for 6 months. Tibial BMD at baseline and at 3 and 6 months post-OVX, three-point-bending of the femur, and body and uterine weight at the study end were examined.

RESULTS

BMD percentage change from baseline of the whole tibia was similar in control and OVX + SID rats at 3 months (-3.02% vs -4.67%, P = not significant), revealing a strong osteoprotective effect. At 6 months, the corresponding changes were -6.02% versus -14.37%, P < 0.05, indicating a greater bone loss in treated rats, albeit significantly less than the OVX change (-20.46%; OVX vs OVX + SID, P < 0.05). The proximal (metaphyseal) tibial BMD percentage change from baseline to 3 and 6 months between the OVX and OVX + SID groups (-26.47% vs -15.57% and -31.22% vs -16.57%, respectively) was statistically significant, demonstrating that SID preserved the proximal tibial BMD of the OVX + SID group significantly. Three-point-bending showed a significant increase in the treated compared with the OVX groups. Body and uterine weights were similar in the OVX and treated groups.

CONCLUSIONS

SID significantly protected tibial bone loss and improved femoral biomechanical strength in OVX + SID rats compared with OVX rats.

Effects of Sideritis euboea (Lamiaceae) Aqueous Extract on IL-6, OPG and RANKL Secretion by Osteoblasts

The water extract obtained from the aerial parts of Sideritis euboea (Lamiaceae), which is known in Greece as ‘mountain tea’, was investigated by determining the in vitro effect of this extract on the IL-6, OPG and RANKL secretion by osteoblasts, three important molecules in osteoblast-osteoclast interplay. The results showed that this extract reduced significantly the secretion of IL-6 by KS-483 osteoblasts, while it also suppressed RANKL secretion, with both effects being dose-dependent and more potent at the higher concentrations tested (50, 100 μg/mL). We further determined the chemical profile of the extract by applying an analytical U-HPLC-DAD-ESIMS/MS method using the high resolution hybrid LTQ-Orbitrap Discovery spectrometer. An ESI source in negative mode was employed. The analysis indicated that the water extract of S. euboea is rich in flavonoid glycosides, and phenylpropanoid glycosides.

Anti-inflammatory, free radical-scavenging, and metal-chelating activities of Malva parviflora

CONTEXT

Malva parviflora L. (Malvaceae) is widely distributed throughout Africa. It has several uses in traditional medicinal practice. Leaves of this plant are used in the treatment of some inflammatory disorders.

OBJECTIVE

The anti-inflammatory and the antioxidant activities of the methanol extract (Met. E) and aqueous extract (Aq. E) of M. parviflora leaves were investigated.

MATERIALS AND METHODS

Croton oil-induced ear edema and acetic acid-induced vascular permeability were applied as acute inflammatory models to evaluate the anti-inflammatory activity of the extracts. The antioxidant effects were evaluated using the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical assay and the measurement of the metal-chelating activity.

RESULTS

Results demonstrated that Met. E inhibited the croton oil-induced ear edema by 57%. In contrast, the Aq. E did not show any activity. Furthermore, Met. E and Aq. E inhibited significantly the acetic acid-induced vascular permeability by 36 and 40%, respectively. However, Met. E and Aq. E exerted a strong scavenging activity with IC(50) values of 89.03 ± 2.65 and 76.67 ± 0.29 µg/mL, respectively. Moreover, Met. E and Aq. E were able to chelate ferrous ions in a concentration-dependent manner.

DISCUSSION AND CONCLUSION

These findings demonstrate that M. parviflora leaf extracts possess anti-inflammatory and antioxidant activities and thus have great potential as an interesting source for natural health products.

Sideritis spp.: uses, chemical composition and pharmacological activities--a review

The genus Sideritis (Lamiaceae) comprises more than 150 perennial and annual vegetal species widely distributed in the Mediterranean area, together with Canary and Madeira islands. It is a controversial botanic genus, with a complex taxonomical classification due to the high number of hybridizations that occur between species; their study requires a deep research experience. Sideritis species have been traditionally used as teas for feeding, flavoring agents and in folk medicine as antiinflammatory, antiulcerative, antimicrobial, vulnerary, antioxidant, antispasmodic, anticonvulsant, analgesic and carminative agents. The chemical components found in Sideritis genus include terpenes, flavonoids, essential oil, iridoids, coumarins, lignanes and sterols, among others. Diterpenes, flavonoids and essential oil occur in almost every species and are the main compounds responsible for the observed in vivo and in vitro pharmacological activities. The aim of this review is to provide a comprehensive overview on the botanical, phytochemical and pharmacological aspects from the genus Sideritis, with the objective of establishing scientific basis that explains its ethnopharmacological use.

Antioxidant and anticholinesterase activity evaluation of ent-kaurane diterpenoids from Sideritis arguta

The petroleum ether and acetone extracts of the aerial parts of Sideritis arguta afforded two new and six known diterpenoids with the ent-kaurane skeleton. The structures of the new diterpenoids were determined as ent-7alpha,18-diacetoxy-16beta-hydroxykaurane (diacetyldistanol) (1) and ent-7alpha-acetoxy,15alpha,18-dihydroxykaur-16-ene (15-epi-eubol) (2) by spectroscopic data interpretation. Antioxidant potential was investigated for the ent-kauranes and the plant extracts by three methods (beta-carotene bleaching, free-radical scavenging, and superoxide-anion scavenging activity). Acetylcholinesterase and butyrylcholinesterase inhibitory activity were also evaluated, and the ent-kauranes eubol (3), sideroxol (5), and 7-epi-candicandiol (6) exhibited moderate butyrylcholinesterase inhibitory activity.