In vitro antioxidant properties and phenolic composition of Salvia halophila Hedge from Turkey

Cationic biopolymer decorated Asiatic Acid and Centella asiatica extract incorporated liposomes for treating early-stage Alzheimer's disease: An In-vitro and In-vivo investigation

Background: Asiatic acid (AA) is a naturally occurring triterpenoid derivative of Centella asiatica (CA) with neuroprotective effect. The study aimed to design an ideal oral drug delivery system to treat Alzheimer's disease (AD) and develop chitosan-embedded liposomes comprising an extract of CA (CLCAE) and compare them with the chitosan-coated liposomes of asiatic acid (CLAA) for oral delivery to treat the initial phases of AD.  Methods: The solvent evaporation technique was used to develop CLCAE and CLAA, optimised with the experiment's design, and was further evaluated. Results: Nuclear magnetic resonance (NMR) studies confirmed coating with chitosan. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) indicated the successful formation of CLCAE and CLAA. Differential scanning colorimetry (DSC) confirmed the drug-phospholipid complex. Furthermore, the rate of  in vitro release of CLCAE and CLAA was found to be 69.43±0.3 % and 85.3±0.3 %, respectively, in 24 h.  Ex vivo permeation of CLCAE and CLAA was found to be 48±0.3 % and 78±0.3 %, respectively. In the Alcl3-induced AD model in rats, disease progression was confirmed by Y-maze, the preliminary histopathology evaluation showed significantly higher efficacy of the prepared liposomes (CLCAE and CLAA) compared to the Centella asiatica extract (CAE) and they were found to have equivalent efficacy to the standard drug (rivastigmine tartrate). The considerable increase in pharmacodynamic parameters in terms of neuronal count in the CLAA group indicated the protective role against Alcl3 toxicity and was also confirmed by assessing acetylcholine (Ach) levels. The pharmacokinetic study, such as C _max, T _max, and area under curve (AUC) parameters, proved an increase in AA bioavailability in the form of CLAA compared to the pure AA and CLCAE forms. Conclusion: The preclinical study suggested that CLAA was found to have better stability and an ideal oral drug delivery system to treat AD.

Phytochemical profile, antioxidant, antiproliferative, and enzyme inhibition-docking analyses of Salvia ekimiana Celep & Doğan

Salvia ekimiana Celep & Doğan is an endemic species of Turkey. To our knowledge, the number of studies on biological activities and phytochemical profiling of this plant is quite limited. Therefore, this study aimed to analyze its activities and phytochemical content in detail. The qualitative-quantitative compositions were determined via spectrophotometric and chromatographic (LC-MS/MS and HPLC) techniques. 1,1-Diphenyl-2-picrylhydrazyl radical (DPPH^•) and 2,2'-Azino-bis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS^•+) radical scavenging and ascorbate-iron (III)-catalyzed phospholipid peroxidation experiments were performed to measure antioxidant capacity. Hyaluronidase, collagenase, and elastase enzyme inhibition tests were determined in vitro using a spectrophotometer. Antiproliferative activity was evaluated in human lung cancer (A549) and human breast cancer (MCF7) cells. The murine fibroblast (L929) cell line was used as a normal control cell. While the subextract rich in phenolic compounds was n-butanol extract, rosmarinic acid was defined as the main secondary metabolite. The highest antioxidant activity observed for the n-butanol subextract included the following: DPPH^• EC50: 0.08±0.00 mg/mL, TEAC/ABTS: 2.19±0.09 mmol/L Trolox, MDA EC50: 0.42±0.03 mg/mL. The methanolic extract, the ethyl acetate, and n-butanol subextracts displayed significant inhibitory activity on collagenase, while the other subextracts did not show any inhibitory activity on hyaluronidase and elastase. Due to strong interactions with their active sites, molecular docking showed luteolin 7-glucuronide, apigenin 7-glucuronide, and luteolin 5-glucoside had the highest binding affinity with target enzymes. The chloroform subextract showed significant cytotoxicity in all cell lines. These novel results revealed that S. ekimiana has strong antioxidant, collagenase enzyme inhibitory, and cytotoxic potential.

Salvia Species as Nutraceuticals: Focus on Antioxidant, Antidiabetic and Anti-Obesity Properties

Salvia plants belong to the Lamiaceae family and are recognized as being strongly aromatic, being widely used for different purposes in culinary or traditional medicine. These plants are well recognized as being rich in phenolic acids, flavonoids and terpenic compounds, which exhibit health-beneficial activities, protecting against oxidative and inflammatory-related diseases, such as diabetes and obesity. Because of these properties, phytochemicals from Salvia species have been investigated as health promoting agents, for application in distinct fields. However, the growing demand for natural products with possible uses and applications in industry requires scientific validation studies. This review consists of a compilation of relevant studies with an emphasis on the antioxidant, antidiabetic and anti-obesity properties of phenolic-rich extracts from Salvia plants.

Determination of Bioactive Compounds in Sequential Extracts of Chia Leaf (Salvia hispanica L.) Using UHPLC-HRMS (Q-Orbitrap) and a Global Evaluation of Antioxidant In Vitro Capacity

Consumers’ interest in foods that are nutritionally balanced and with health benefits has increased. The food industry is paying attention to the use of the ancestral seed Salvia hispanica L., commonly known as chia. At present, only chia seeds, which are a natural source of omega-3 and omega-6, fiber, proteins, and natural antioxidants, are commercialized. Although some studies reveal the presence of several bioactive compounds, such as polyphenols (e.g., vitexin, orientin, and some hydroxycinnamic acids) in chia leaf methanolic extracts, the chia plant is commonly used as fertilizer or treated as waste after harvest. Therefore, it can represent a by-product that could be considered a great source of bioactive compounds with unexplored potential in medicine and food industry applications. In this work, UHPLC-HRMS (Q-Orbitrap) was employed to tentatively identify and determine the bioactive compounds present in different leaf extracts of chia plants of black and white seed phenotype obtained with solvents of different polarity (ethanol, ethyl acetate, dichloromethane, and hexane) to address chia plant by-product revalorization. The chemical antioxidant capacity was also studied and correlated to the found bioactive compounds. In these experiments, black chia showed a higher antioxidant capacity than white chia in the ethanolic extracts. Moreover, experiments on cellular antioxidant activity were also performed with a predominance of the white chia extract. It is noted that the cellular antioxidant activity results make chia ethanolic extracts promising antioxidants.

Biosynthesis of antioxidative enzymes and polyphenolics content in calli cultures of Prunella vulgaris L. in response to auxins and cytokinins

Prunella vulgaris L. is one of the therapeutic herbs containing various polyphenolics, which is used for multiple medicinal purposes. In this study, plant growth regulators (PGRs)-induced calli cultures from seed-derived leaf explants were exploited for the production of stress enzymes and polyphenolics. A growth curve was plotted for each PGR for 49 days period, which showed a distinct lag, log and decline phases. Here, the combination of naphthalene acetic acid (NAA) and 6-benzyleadenine (BA; 0.5 and 2.0 mg l^-1) produced maximum fresh (6.32 FW-g/100 ml) and dry biomass (0.75 DW-g/100 ml) in contrast to control. The maximum synthesis of SOD (0.0154 FW-nM/min/mg) was detected on media comprising mixture of NAA and BA (1.5 mg l^-1), while POD enzyme (0.366 FW-nM/min/mg) was higher at 0.5 mg l^-1 NAA and 2, 4-dichlorophenoxy acetic acid. Further, NAA and BA (1.5 and 2.0 mg l^-1) boosted up the synthesis of phenolics (18.83 GAE-mg/g-DW) and flavonoids content (18.05 RE-mg/g-DW) than control. Moreover, NAA of 1.0 and 2.0 mg l^-1 were found supportive for maximum antioxidant activity (87.4%) and total protein (716 µg BSAE/mg-DW). This study will contribute in the development of cell culture in fermenter and synthesis of antioxidant secondary metabolites for commercial uses.

Potential Antioxidant and Enzyme Inhibitory Effects of Nanoliposomal Formulation Prepared from Salvia aramiensis Rech. f. Extract

Salvia aramiensis Rech. f. is a species that grows only in Hatay, Turkey and is used as a traditional stomachic tea. Neither the chemical composition nor the potential bioactivity of the plant has been investigated before. Antioxidant activity (1,1-Diphenyl-2-picrylhydrazyl Radical (DPPH^●) and 2,2’-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS^+●) radical scavenging and β-carotene/linoleic acid co-oxidation) of 70% methanol, 70% ethanol extracts, and 2% infusion obtained from S. aramiensis aerial parts were determined. The effect of 70% methanol extract on collagenase and elastase enzyme inhibition and its chemical composition via chromatographic methods (LC-MS/MS and HPLC) were analyzed. Nanoliposomes were developed with 70% methanol extract, were characterized, and were evaluated. The key parameters for the most active 70% methanol extract included the following DPPH^•EC₅₀: 28.4 µg/mL, Trolox equivalent antioxidant capacity (TEAC)/ABTS: 1.77 ± 0.09 mmol/L/Trolox. Furthermore 70% methanol extract showed more than 50% inhibition on collagenase and elastase enzymes at all the concentrations. The main component of the extract, rich in phenolic compounds, has been identified as rosmarinic acid; 83.7 µg/mL extract was released from the nanoliposomal formulation. The extract and its formulation are found to be nontoxic on the L929 fibroblast cell line. This study successfully developed a long-term antioxidant and enzyme inhibitory formulation containing S. aramiensis, which has been used safely among the public for years.

Rosmarinic and carnosic acid contents and correlated antioxidant and antidiabetic activities of 14 Salvia species from Anatolia

Herbal medicine has been used worldwide as an alternative treatment. Salvia genus is one of the most remarked herbs which is traditionally used in the treatment of many diseases. Therefore, it is a crucial issue to reveal the chemical and biological profiles of different Salvia species. Rosmarinic and carnosic acid are the most well-known bioactive components generally accepted as the main antioxidant compounds in Salvia. This study firstly aims the determination of rosmarinic and carnosic acid contents of 14 Anatolian Salvia species by a simple and rapid capillary electrophoresis method. Moreover, the antioxidant activities and total phenolic contents of the Salvia samples were investigated. α-Glucosidase enzyme inhibitory effects of the samples were tested concerning their antidiabetic activities. The rosmarinic acid contents in the samples were well-correlated with the bioactivities.

Evaluation of antiamnesic activity of Salvia multicaulis essential oil on scopolamine-induced amnesia in rats: in vivo and in silico approaches

Plants of genus Salvia have been used in folk medicine for wound healing, in the alleviation of stomach, liver, and rheumatism pains, as antioxidant, cognitive-enhancer, sedative and antiseptic, stimulant and tonic agents. The present study aimed to evaluate whether Salvia multicaulis essential oil (1% and 3%) administered for 21 days attenuates cognitive deficits and exhibits anxiolytic and antidepressant-profile in the scopolamine-induced amnesia in rats. Rats were randomly divided into six groups (n = 6): (1) control, (2) scopolamine (Sco, 0.7 mg/kg) (3, 4) S. multicaulis essential oil treatment groups (SEO, 1% and 3%), (5) diazepam (DIAZ, 1.5 mg/kg) and (6) tramadol (TRM, 10 mg/kg). To establish an animal model of amnesia, Sco (0.7 mg/kg), a muscarinic acetylcholine receptor antagonist, was injected into male Wistar rats. Y-maze (memory), radial arm-maze (memory), elevated plus-maze (anxiety), and forced swimming (depression) tests were employed. Molecular interactions of chemical compounds from the essential oil with the GABA_A receptor was explored via molecular docking experiments. Using behavioral tests, we demonstrated that inhalation of S. multicaulis essential oil exerts significant antiamnesic activity as well as anxiolytic-antidepressant-like effects in the Sco-treated rats. Our data revealed that S. multicaulis oil could act as a promising phytopharmaceutical agent for improving dementia-related abnormalities.

The Health-Benefits and Phytochemical Profile of Salvia apiana and Salvia farinacea var. Victoria Blue Decoctions

Salvia apiana and Salvia farinacea var. Victoria Blue decoctions were screened for diverse bioactivities, including the ability to counteract oxidative and inflammatory events, as well as to act as cytotoxic and antimicrobial agents. Both extracts showed good activities and that of S. apiana origin was particularly effective regarding the ability to prevent lipid peroxidation and to prevent nitric oxide (NO●) production in lipopolysaccharide (LPS)-activated murine macrophage RAW 264.7 cell line (EC₅₀ = 50 μg/mL). Moreover, it displayed high cytotoxic capacity against hepatocellular carcinoma HepG2, cervical carcinoma HeLa, and breast carcinoma cells MCF-7, but comparatively low effects in porcine liver primary cells, which highlights its selectivity (GI₅₀ = 41–60 μg/mL vs. 362 μg/mL, respectively). Further, it exhibited inhibitory and lethal potential against a panel of Gram-positive and Gram-negative bacteria. It is possible that the bioactive properties of the two Salvia extracts are associated to their phenolic components and, in the particular case of S. apiana, to its richness in phenolic terpenes, namely in rosmanol, hydroxycarnosic acid and a derivative of sageone, which were found in the extract.

Essential Oil and Bioactive Compounds Variation in Myrtle (Myrtus communis L.) as Affected by Seasonal Variation and Salt Stress

The effect of different NaCl concentrations (control, 2, 4 and 6 dS/m) and three harvesting times in different seasons including spring (9 April), summer (5 July), and fall (23 September) was evaluated on essential oil (EO) yield, composition, phenolic, flavonoid content, and antioxidant activity of myrtle. Essential oil yield ranged from 0.2% in control and fall to 1.6% in moderate salinity (4 dS/m) and spring season. The main constituents obtained from gas chromatography/mass spectrometry analysis were α-pinene, 1,8-cineole, limonene, linalool, α-terpineol, and linalyl acetate in which α-pinene ranged from 11.70% in moderate and fall to 30.99% in low salinity (2 dS/m) and spring, while 1,8-cineole varied from 7.42% in high salinity (6 dS/m) and summer to 15.45% in low salinity and spring, respectively. Salt stress also resulted in an increase in total phenolic, flavonoid content, and antioxidant activity. The highest antioxidant activity based on DPPH radical scavenging activity, reducing power (FTC) and β-carotene/linoleic acid model systems was found in plants harvested in spring and summer in high stress condition. The lowest IC₅₀ values obtained in 6 dS/m in spring (375.23 μg/ml) followed by summer (249.41 μg/ml) and fall (618.38 μg/ml). Eight major phenolic and flavonoid compounds were determined in three harvesting times using high performance liquid chromatography analysis. In overall, late harvesting time of myrtle in fall can lead to reduce the most of major EO components, while it can improve the amount of phenolic acids.

Acidic Potassium Permanganate Chemiluminescence for the Determination of Antioxidant Potential in Three Cultivars of Ocimum basilicum

Ocimum basilicum, a member of the family Lamiaceae, is a rich source of polyphenolics that have antioxidant properties. The present study describes the development and application of an online HPLC-coupled acidic potassium permanganate chemiluminescence assay for the qualitative and quantitative assessment of antioxidants in three cultivars of O. basilicum grown under greenhouse conditions. The chemiluminescence based assay was found to be a sensitive and efficient method for assessment of total and individual compound antioxidant potential. Leaves, flowers and roots were found to be rich reserves of the antioxidant compounds which showed intense chemiluminescence signals. The polyphenolics such as rosmarinic, chicoric, caffeic, p-coumaric, m-coumaric and ferulic acids showed antioxidant activity. Further, rosmarinic acid was found to be the major antioxidant component in water-ethanol extracts. The highest levels of rosmarinic acid was found in the leaves and roots of cultivars "holy green" (14.37; 11.52 mM/100 g DW respectively) followed by "red rubin" (10.02; 10.75 mM/100 g DW respectively) and "subja" (6.59; 4.97 mM/100 g DW respectively). The sensitivity, efficiency and ease of use of the chemiluminescence based assay should now be considered for its use as a primary method for the identification and quantification of antioxidants in plant extracts.

Effect of reverse photoperiod on in vitro regeneration and piperine production in Piper nigrum L

In this study, a novel approach for in vitro regeneration of Piper nigrum L. has been applied in order to increase healthy biomass, phytochemicals and piperine production via reverse photoperiod (16hD/8hL). Leaf portions of the seed-derived plants were placed on an MS-medium fortified with different PGRs. Under 16hD/8hL, thidiazuron (TDZ; 4.0 mg L⁻¹) and BA (1.5 mg L⁻¹) was found to be the most effective (<90%) in callus induction. Two concentrations (1.5, 2.0 mg L⁻¹) of the IBA produced>80% shoots from callus cultures. Healthy shoots were transferred to rooting medium and higher percentage of rooting (<90%) was observed on IBA (1.5 mg L⁻¹). These in vitro tissues were subjected to amino acid analysis, spectrophotometry, and HPLC. ARG, SER, THR, and TYR were the most abundant components out of 17 amino acids. Higher amino acid production was observed under normal photoperiod (16hL/8hD) than under reverse photoperiod (16hD/8hL). The highest total phenolic content (TPC; 9.91 mg/g-DW) and flavonoid content (7.38 mg/g-DW) were observed in callus cultures incubated under 16hL/8hD than other tissues incubated under 16hD/8hL photoperiod. Higher DPPH and PoMo activities were observed in tissues incubated under 16hL/8hD photoperiod, while ABTS and Fe²⁺ chelating activities were found higher in tissues incubated under reverse photoperiod. Significant quantities of piperine content were observed in all tissues except callus cultures. These results suggest that reverse photoperiod is a promising approach for callus induction, phytochemicals and piperine production for commercial applications.

Methods for Extraction and Determination of Phenolic Acids in Medicinal Plants: A Review

Phenolic acids constitute a group of potentially immunostimulating compounds. They occur in all medicinal plants and are widely used in phytotherapy and foods of plant origin. In recent years, phenolic acids have attracted much interest owing to their biological functions. This paper reviews the extraction and determination methods of phenolic acids in medicinal plants over the last 10 years. Although Soxhlet extraction and ultrasonic assisted extraction (UAE) are commonly used for the extraction of phenolic acids from plant materials, alternative techniques such as supercritical fluid extraction (SFE), and accelerated solvent extraction (ASE) can also be used. After extraction, phenolic acids are determined usually by liquid chromatography (LC) owing to the recent developments in this technique, especially when it is coupled with mass spectrometry (MS). Also detection systems are discussed, including UV-Vis, diode array, electrochemical and fluorimetric. Other popular techniques for the analysis of this group of secondary metabolites are gas chromatography coupled with mass spectrometry (GC-MS) and capillary electrophoresis (CE).

Anthraquinone profile, antioxidant and antimicrobial activity of bark extracts of Rhamnus alaternus, R. fallax, R. intermedia and R. pumila

The quantity of phenols, as well as antioxidant and antimicrobial activities, were investigated in bark of Rhamnus alaternus L., R. fallax Boiss., R. intermedia Steud. et Hochst., and R. pumila Turra from natural stands in Croatia. The most abundant anthraquinones in the investigated extracts were chrysophanol in R. alaternus (3.14 mg/g), emodin in R. pumila (0.339 mg/g), and physcion in R. fallax (2.70 mg/g) and R. intermedia (0.285 mg/g). The species exhibiting the highest antioxidant activity were R. fallax and R. pumila. A positive correlation was observed between total phenolic and flavonoid levels of the extracts and antioxidant activity in some of the assays. All species showed antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Candida albicans, Aspergillus niger and Microsporum gypseum with minimal inhibitory concentrations equal to or below 2.500 mg/mL. The results indicate that the investigated Rhamnus species are a source of anthraquinones and other phenols, which act as multifunctional antioxidants with antimicrobial activity.