Unusual antioxidant behavior of alpha- and gamma-terpinene in protecting methyl linoleate, DNA, and erythrocyte

Novel assaying method for the accurate and rapid analysis of antioxidant total capacity based on hexachloroiridate(IV)

We introduce a novel method, namely IrRAC, for assessing total antioxidant capacity utilizing the single electron oxidant hexachloroiridate(IV). This method leverages the 488 nm absorption band of [IrCl6]2- largely reducing interferences from antioxidants and their oxidation products. [IrCl6]2- is stable 6 h in phosphate-buffered saline (PBS) ensuring consistent and reproducible absorbance readings and rendering spectrophotometric determinations under physiological neutrality. Individual assessments of 23 antioxidants reveal a linear correlation between decreasing absorbance and increasing antioxidant concentration. When the IrRAC assay was compared with several established water-based methods, strong correlations were found. Importantly, [IrCl6]2- shows a minimal oxidation of non-antioxidative substances. Moreover, IrRAC performs well with synthetic antioxidant mixtures and real samples, highlighting that the nature of antioxidants dominates the assay without much disturbance. Commercial availability of K2[IrCl6] eliminates the need of pretreatment of the oxidant. Undoubtedly, the new method confers a compelling and cost-effective alternative to the existing electron transfer-based methodologies.

Non-clinical investigations about cytotoxic and anti-platelet activities of gamma-terpinene

Gamma-terpinene (γ-TPN) is a cyclohexane monoterpene isolated from plant essential oils, such as tea tree (Melaleuca alternifolia), oregano (Origanum vulgare), rosemary (Rosmarinus officinalis L.), thyme (Thymus vulgaris Marchand), and eucalyptus (Eucalyptus sp.). Terpenes are widely studied molecules pharmacologically active on the cardiovascular system, hemostasis, and antioxidant actions. Herein, it was investigated the cytotoxic and antiplatelet activity of γ-TPN using different non-clinical laboratory models. For in silico evaluation, the PreADMET, SwissADME, and SwissTargetPrediction softwares were used. Molecular docking was performed using the AutoDockVina and BIOVIA Discovery Studio databases. The cytotoxicity of γ-TPN was analyzed by the MTT assay upon normal murine endothelial SVEC4-10 and fibroblast L-929 cells. Platelet aggregation was evaluated with platelet-rich (PRP) and platelet-poor (PPP) plasma from spontaneously hypertensive rats (SHR), in addition to SVEC4-10 cells pre-incubated with γ-TPN (50, 100, and 200 µM) for 24 h. SHR animals were pre-treated by gavage with γ-TPN for 7 days and divided into four groups (negative control, 25, 50, and 100 mg/kg). Blood samples were collected to measure nitrite using the Griess reagent. Gamma-TPN proved to be quite lipid-soluble (Log P = +4.50), with a qualified profile of similarity to the drug, good bioavailability, and adequate pharmacokinetics. It exhibited affinity mainly for the P2Y12 receptor (6.450 ± 0.232 Kcal/mol), moderate cytotoxicity for L-929 (CC50 = 333.3 µM) and SVEC 4-10 (CC50 = 366.7 µM) cells. The presence of γ-TPN in SVEC 4-10 cells was also able to reduce platelet aggregation by 51.57 and 44.20% at lower concentrations (50 and 100 µM, respectively). Then, γ-TPN has good affinity with purinergic receptors and an effect on the reversal of platelet aggregation and oxidative stress, being promising and safe for therapeutic targets and subsequent studies on the control of thromboembolic diseases.

Crithmum maritimum L.-Study on the Histochemical Localization of Essential Oil

Crithmum maritimum L. is a perennial halophyte plant that is a medicinal herb known by people from different cultures since ancient times. However, the therapeutic potential of this halophyte has not been completely investigated, and the scientific data on it are limited. The purpose of the present study was to estimate the chemical composition of the essential oil (EO) obtained from the aerial parts of Crithmum maritimum L. growing wild in Bulgaria, as well as the histolocalization of secretory structures for the synthesis and accumulation of volatile oils. The results obtained on the EO composition of Bulgarian Crithmum maritimum L. provide an opportunity to reveal potential future applications in various fields, such as medicine, pharmacy, agriculture, food, and the cosmetic industry. Gas chromatography with mass spectrometry was performed to assess the chemical profile of the isolated EO. The phenylpropanoid dillapiole was identified as the major compound in the EO, accounting for 34.09% of the total EO. Monoterpene hydrocarbons represented 62.07% of the total oil composition. γ-Terpinene, D-limonene, and β-pinene were the most abundant monoterpene hydrocarbons in the composition of the EO. In addition, histochemical localization of EO in the stem and leaves of Crithmum maritimum L. was carried out. The secretory structures were located in the cortical region of the stem and in the mesophyll tissues of the leaves in the form of secretory ducts. The performed histochemical analysis confirmed the lipophilic nature of the secretion from the duct cells. This is the first report related to the histolocalization and chemical composition of the EO from Bulgarian Crithmum maritimum L. Furthermore, our data indicate some potential possibilities for the evaluation of the therapeutic activity of the EO obtained from this plant species and outline its future applications as a therapeutic agent. Also, the EO from the studied halophyte plant has prominent potential to be used as a biopesticide, which is an environmentally friendly option compared to standard pesticides.

Essential Oils: Chemistry and Pharmacological Activities

In this review, we provide an overview of the current understanding of the main mechanisms of pharmacological action of essential oils and their components in various biological systems. A brief introduction on essential oil chemistry is presented to better understand the relationship of chemical aspects with the bioactivity of these products. Next, the antioxidant, anti-inflammatory, antitumor, and antimicrobial activities are discussed. The mechanisms of action against various types of viruses are also addressed. The data show that the multiplicity of pharmacological properties of essential oils occurs due to the chemical diversity in their composition and their ability to interfere with biological processes at cellular and multicellular levels via interaction with various biological targets. Therefore, these natural products can be a promising source for the development of new drugs.

Actinomycetes as Producers of Biologically Active Terpenoids: Current Trends and Patents

Terpenes and their derivatives (terpenoids and meroterpenoids, in particular) constitute the largest class of natural compounds, which have valuable biological activities and are promising therapeutic agents. The present review assesses the biosynthetic capabilities of actinomycetes to produce various terpene derivatives; reports the main methodological approaches to searching for new terpenes and their derivatives; identifies the most active terpene producers among actinomycetes; and describes the chemical diversity and biological properties of the obtained compounds. Among terpene derivatives isolated from actinomycetes, compounds with pronounced antifungal, antiviral, antitumor, anti-inflammatory, and other effects were determined. Actinomycete-produced terpenoids and meroterpenoids with high antimicrobial activity are of interest as a source of novel antibiotics effective against drug-resistant pathogenic bacteria. Most of the discovered terpene derivatives are produced by the genus Streptomyces; however, recent publications have reported terpene biosynthesis by members of the genera Actinomadura, Allokutzneria, Amycolatopsis, Kitasatosporia, Micromonospora, Nocardiopsis, Salinispora, Verrucosispora, etc. It should be noted that the use of genetically modified actinomycetes is an effective tool for studying and regulating terpenes, as well as increasing productivity of terpene biosynthesis in comparison with native producers. The review includes research articles on terpene biosynthesis by Actinomycetes between 2000 and 2022, and a patent analysis in this area shows current trends and actual research directions in this field.

Chemical and Biological Characterization of Melaleuca alternifolia Essential Oil

The essential oil of Melaleuca alternifolia, commonly known as tea tree oil, has many beneficial properties due to its bioactive compounds. The aim of this research was to characterize the tea tree essential oil (TTEO) from Slovakia and its biological properties, which are specific to the chemical composition of essential oil. Gas chromatography/mass spectroscopy revealed that terpinen-4-ol was dominant with a content of 40.3%. γ-Terpinene, 1,8-cineole, and p-cymene were identified in contents of 11.7%, 7.0%, and 6.2%, respectively. Antioxidant activity was determined at 41.6% radical inhibition, which was equivalent to 447 μg Trolox to 1 mL sample. Antimicrobial activity was observed by the disk diffusion method against Gram-positive (G⁺), Gram-negative (G^-) bacteria and against yeasts, where the best antimicrobial activity was against Enterococcus faecalis and Candida albicans with an inhibition zone of 10.67 mm. The minimum inhibitory concentration showed better susceptibility by G⁺ and G^- planktonic cells, while yeast species and biofilm-forming bacteria strains were more resistant. Antibiofilm activity was observed against Pseudomonas fluorescens and Salmonella enterica by MALDI-TOF, where degradation of the protein spectra after the addition of essential oil was obtained. Good biological properties of tea tree essential oil allow its use in the food industry or in medicine as an antioxidant and antimicrobial agent.

A Comparative Study of the Chemical Composition by SPME-GC/MS and Antiradical Activity of Less Common Citrus Species

Citrus secondary metabolites, such as terpene compounds, are very important for human health due to their bioactivity including anti-inflammatory, anti-cancer, and antioxidant effects. In this work, for the first time, the volatile chemical composition of peels and juices from four different Citrus species (C. junos, Citrus × aurantium, C. aurantium 'Bizzarria' and C. medica 'Florentina', commonly known as Yuzu jeune, Oni Yuzu, Bizzarria orange and Florence cedar, respectively) was investigated by Solid-Phase Microextraction-Gas Chromatography/Mass Spectrometry (SPME-GC/MS) technique and the antiradical activity was also examined. The results showed that limonene and γ-terpinene were the main volatile substances detected both in the juices and in the peels, followed by other minority compounds responsible for the phyto-complex of the unique aromas which characterize each individual analyzed Citrus species. Principal component analysis (PCA), performed on volatile compounds, showed both some correlation as well as a clear separation between the juice and the peel of each species. Among them, Oni Yuzu juice was found to be the richest in total polyphenols and flavonoids while its capacity to scavenge ABTS^•+ and DPPH^• radicals was similar to that of Yuzu Jeune and Bizzarria orange.

Variability of the Chemical Composition and Bioactivity between the Essential Oils Isolated from Male and Female Specimens of Hedyosmum racemosum (Ruiz & Pav.) G. Don

Hedyosmum racemosum (Ruiz & Pav.) G. is a native species of Ecuador used in traditional medicine for treatment of rheumatism, bronchitis, cold, cough, asthma, bone pain, and stomach pain. In this study, fresh H. racemosum leaves of male and female specimens were collected and subjected to hydrodistillation for the extraction of the essential oil. The chemical composition of male and female essential oil was determined by gas chromatography–gas chromatography equipped with a flame ionization detector and coupled to a mass spectrometer using a non-polar and a polar chromatographic column. The antibacterial activity was assayed against five Gram-positive and two Gram-negative bacteria, and two dermatophytes fungi. The scavenging radical properties of the essential oil were evaluated by DPPH and ABTS assays. The chemical analysis allowed us to identify forty-three compounds that represent more than 98% of the total composition. In the non-polar and polar column, α-phellandrene was the principal constituent in male (28.24 and 25.90%) and female (26.47 and 23.90%) essential oil. Other main compounds were methyl chavicol, germacrene D, methyl eugenol, and α-pinene. Female essential oil presented a strong activity against Klebsiella pneumoniae (ATCC 9997) with an minimum inhibitory concentration (MIC) of 500 μg/mL and a scavenging capacity SC₅₀ of 800 µg/mL.

Comprehensive Evaluation on the Use of Thymus vulgaris Essential Oil as Natural Additive against Different Serotypes of Salmonella enterica

Essential oils were proposed as natural additives to ensure food safety and quality in a more sustainable approach. The chemical composition of Thymus vulgaris essential oil (TV-EO) collected from Morocco, its antioxidant and antimicrobial activity against different serotypes of Salmonella enterica subsp. enterica was investigated. A mathematical model was implemented to predict the Salmonella behavior when exposed to TV-EO. In situ antimicrobial activity and sensory influence were tested in minced poultry meat experimentally contaminated with Salmonella and treated with TV-EO. Hydrodistillation was used to extract TV-EO, and gas chromatography-mass spectrometry (GC-MS) analysis found thymol as the most representative compound. Results of the antioxidant activity showed an IC50 of 0.29 ± 0.04 mg/mL, EC50 of 0.74 ± 0.08 mg/mL, and RC50 of 0.59 ± 0.06 mg/mL. All the Salmonella strains were susceptible to TV-EO with performing results for the disc diffusion method (inhibition diameters ranged between 24 ± 0.4 mm and 32 ± 0.6 mm), determination of minimum inhibitory concentration (MIC; 0.5%) and minimum bactericidal concentration (MBC; 1%), sublethal-injured cells (7.99 ± 0.08%), in situ activity (growth inhibition after 3 days), and meat sensory preservation (up to 1 week). The implemented mathematical model well fitted the Salmonella growth curve. TV-EO with significant antioxidant and antibacterial activities was suitable to ensure food safety and quality consistent with the new sustainable trends in the food field.

Bioassay-guided identification of α-amylase inhibitors in herbal extracts

This study focuses on the health benefits of several fresh herbs that are commonly used in the Mediterranean diet. Antioxidant activity, phytosterol content and α-amylase inhibitory activity of fresh basil, lavender, oregano, rosemary, sage, and thyme are analyzed and compared. High-performance thin-layer chromatography (HPTLC) combined with effect directed analysis was used to detect and quantify biological active compounds on chromatograms. The highest antioxidant activity was measured in the extract from oregano leaf, while the highest terpenoid content was in basil leaf extract. All extracts except lavender leaf and lavender flower extracts showed α-amylase inhibition. The same compound at hR_F = 68 in basil, oregano, rosemary, sage, and thyme extracts was responsible for α-amylase inhibition. Combined with effect-directed assays and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, hyphenated HPTLC allowed a fast characterization of the active compound. ATR spectral analysis of this band tentatively identified oleanolic acid (or its derivative) to be responsible for the α-amylase inhibition.

Bridging free radical chemistry with drug discovery: A promising way for finding novel drugs efficiently

Many diseases have been regarded to correlate with the in vivo oxidative damages, which are caused by overproduced free radicals from metabolic process or reactive oxygen species (ROS). This background motivates chemists to explore free radical reactions and to design a number of antioxidants, but whether free radical chemistry can be applied to accelerate the efficacy of the drug discovery is still underrepresented. Herein, in light of recent findings as well as kinetics on free radical reaction, the discipline of free radical chemistry is introduced to be a novel tool for finding potential drugs from antioxidant libraries accumulated during the study on free radical chemistry. These antioxidants provide with such abundant types of structural skeleton that might be employed to inhibit oxidations in different biological microenvironments. Although the in vitro characterization on the antioxidative property exerts a potential role of an antioxidant as a prodrug, the in vivo investigation on the property for quenching free radicals will make a final decision for the antioxidant whether it is worthy to be further explored pharmacologically. Therefore, it is reasonable to expect that bridging free radical chemistry with the pharmacological research will provide with a succinct way for finding novel drugs efficiently.

Natural Monoterpenes: Much More than Only a Scent

Terpenes are a widespread group of secondary metabolites that can be found in various family plants such as the Lamiaceae. In view of their numerous valuable biological activities, the industrial production of concrete terpenes and essential oils rich in the substances is intensively studied. Monoterpenes constitute a significant part of the whole group of the aforementioned secondary metabolites. This is due to their numerous biological activities and their ability to permeate the skin. Despite the fact that these substances have gain popularity, they are not comprehensively characterized. The presented review is based on studies of the biological activities of the most important monoterpenes and the essential oils rich in these compounds. The authors focused attention on antioxidant activity, inhibition towards acetyl- and butyrylcholinesterase, and α-amylase and α-glucosidase, antifungal, hepatoprotective, sedative properties, and their skin permeation enhancement.

Enhancing Antioxidant Effect against Peroxyl Radical-Induced Oxidation of DNA: Linking with Ferrocene Moiety!

As a major member in the family of reactive oxygen species, peroxyl radical is able to abstract hydrogen atom from 4-position of ribose, leading to the collapse of DNA strand. Thus, inhibiting oxidative stress with exogenous antioxidants acts as a promising strategy to protect the integrity of DNA structure and is thereby suggested to be a pathway against developments of related diseases. Ferrocene as an organometallic scaffold is widely applied in the design of organometallic drugs, and redox of Fe(II)/Fe(III) in ferrocene offers advantage for providing electron to radicals. Presented herein are our ongoing studies on ferrocene-appended antioxidants, including McMurry reaction applied to construct ferrocifen; Aldol condensation used to prepare ferrocenyl curcumin; Povarov reaction employed to prepare ferrocenyl quinoline; Biginelli reaction used to construct ferrocenyl dihydropyrimidine; Groebke reaction used to synthesize ferrocenyl imidazo[1,2-a]pyridine; and Passerini three-component reaction as well as Ugi four-component reaction applied to synthesize α-acyloxycarboxamide and bisamide, respectively. It is found that ferrocene moiety is able to enhance antioxidative effect of the aforementioned scaffolds even without the aid of phenolic hydroxyl group. The role of ferrocene in enhancing antioxidative effect can be attributable to trapping radicals, decreasing oxidative potential, and increasing the affinity toward DNA strand. Therefore, ferrocene is worthy to be taken into consideration in the design of drugs in relation to DNA oxidation.

Hybrid of Resveratrol and Glucosamine: An Approach To Enhance Antioxidant Effect against DNA Oxidation

Resveratrol exhibits various pharmacological activities, which are dependent upon phenolic hydroxyl groups. In this work, glucosamine, lipoic acid, or adamantanamine moiety was applied for attaching to ortho-position of hydroxyl group in resorcinol moiety of resveratrol (known as position-2). Antioxidant effects of the obtained hybrids were characterized using DNA oxidative systems mediated by ^•OH, Cu²⁺/glutathione (GSH), and 2,2'-azobis(2-amidinopropanehydrochloride) (AAPH), respectively. The glucosyl-appended imine and amine at position-2 of resveratrol were found to show higher inhibitory effects than other resveratrol derivatives against AAPH-induced DNA oxidation. The antioxidative effect was quantitatively expressed by stoichiometric factor ( n, the number of radical-propagation terminated by one molecule of antioxidant). The stoichiometric factors of glucosyl-appended imine and amine of resveratrol increased to 4.74 (for imine) and 4.97 (for amine), respectively, higher than that of resveratrol (3.70) and glucoside of resveratrol (3.49). It was thereby concluded that the combination of resveratrol with glucosamine at position-2 represented a novel pathway for modifying resveratrol structure in the protection of DNA against peroxyl radical-mediated oxidation.

Medicinal properties of terpenes found in Cannabis sativa and Humulus lupulus

Cannabaceae plants Cannabis sativa L. and Humulus lupulus L. are rich in terpenes - both are typically comprised of terpenes as up to 3-5% of the dry-mass of the female inflorescence. Terpenes of cannabis and hops are typically simple mono- and sesquiterpenes derived from two and three isoprene units, respectively. Some terpenes are relatively well known for their potential in biomedicine and have been used in traditional medicine for centuries, while others are yet to be studied in detail. The current, comprehensive review presents terpenes found in cannabis and hops. Terpenes' medicinal properties are supported by numerous in vitro, animal and clinical trials and show anti-inflammatory, antioxidant, analgesic, anticonvulsive, antidepressant, anxiolytic, anticancer, antitumor, neuroprotective, anti-mutagenic, anti-allergic, antibiotic and anti-diabetic attributes, among others. Because of the very low toxicity, these terpenes are already widely used as food additives and in cosmetic products. Thus, they have been proven safe and well-tolerated.

Biological Activities and Safety of Citrus spp. Essential Oils

Citrus fruits have been a commercially important crop for thousands of years. In addition, Citrus essential oils are valuable in the perfume, food, and beverage industries, and have also enjoyed use as aromatherapy and medicinal agents. This review summarizes the important biological activities and safety considerations of the essential oils of sweet orange (Citrus sinensis), bitter orange (Citrus aurantium), neroli (Citrus aurantium), orange petitgrain (Citrus aurantium), mandarin (Citrus reticulata), lemon (Citrus limon), lime (Citrus aurantifolia), grapefruit (Citrus × paradisi), bergamot (Citrus bergamia), Yuzu (Citrus junos), and kumquat (Citrus japonica).

Ethnobotany, phytochemistry and pharmacology of Arctotis arctotoides (L.f.) O. Hoffm.: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Arctotis arctotoides (Asteraceae) is part of the genus Arctotis. Arctotis is an African genus of approximately 70 species that occur widely in the African continent with diverse medicinal values. This plant is used for the treatment of indigestion and catarrh of the stomach, epilepsy, topical wounds and skin disorders among the ethnic groups in South Africa and reported to have a wide spectrum of pharmacological properties.

AIM OF THE REVIEW

The aim of the present review is to appraise the botany, traditional uses, phytochemistry, pharmacological potential, analytical methods and safety issues of A. arctotoides. Additionally, this review will help to fill the existing gaps in knowledge and highlight further research prospects in the field of phytochemistry and pharmacology.

MATERIALS AND METHODS

Information on A. arctotoides was collected from various resources, including books on African medicinal herbs and Zulu medicinal plants, theses, reports and the internet databases such as SciFinder, Google Scholar, Pubmed, Scopus, Web of Science, and Mendeley by using a combination of various meaningful keywords. This review surveys the available literature of the species from 1962 to April 2017.

RESULTS

In vitro and in vivo studies of the medicinal properties of A. arctotoides were reviewed. The main isolated and identified compounds were reported as sesquiterpenes, farnesol derivatives, germacranolide, guaianolides and some steroids, of which, nine were reported as antimicrobial. Monoterpenoids and sesquiterpenoids were the predominant essential oil compound classes of the leaves, flowers, stems and roots. The present review revealed potential pharmacological properties such as anti-oxidant, antibacterial, antifungal and anticancer activities of plant extracts as well as isolated compounds. Moreover, the review reports the safety profile (toxicity) of the crude extracts that had been screened on brine shrimps, rats and human cell lines.

CONCLUSIONS

The present review has focused on the phytochemistry, botany, ethnopharmacology, biological activities and toxicological information of A. arctotoides. On the basis of reported data, A. arctotoides has emerged as a good source of natural medicine for the treatment of microbial infections, skin diseases, anti-inflammatory and anticancer agents and also provides new insights for further isolation of new bioactive compounds, especially the discovery of antimicrobial, anti-inflammatory and anticancer novel therapeutic lead drug molecules. Additionally, intensive investigations regarding pharmacological properties, safety assessment and efficacy with their mechanism of action could be future research interests before starting clinical trials for medicinal practices.

Antibacterial, Antioxidant, and Antiproliferative Activities of Corymbia citriodora and the Essential Oils of Eight Eucalyptus Species

Background: Essential oils (EOs) have shown antimicrobial, antioxidant, and antiproliferative activity, which may, alone or in combination with other substances, potentially be used for the development of new drugs. However, their chemical variability, depending on the species, varieties, or geographical origin (among other factors) determines different bioactivities that need to be evaluated. Methods: The antioxidant activity of Corymbia citriodora and eight Eucalyptus species EOs was determined using two different methods: the scavenging ability of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS+•) and peroxyl free radicals or oxygen radical absorbance capacity (ORAC). Antibacterial activity was evaluated using the microorganisms Streptococcus pneumoniae (strains D39 and TIGR4), and Haemophilus influenza (strain DSM 9999). The essential oils’ minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) was assessed using a microdilution method. The antiproliferative activity was determined using the THP-1 cell line (human acute monocytic leukaemia) with methylthiazolyldiphenyl-tetrazolium bromide assay (MTT). Results:Corymbia citriodora and Eucalyptus viminalis EOs showed the highest ABTS and peroxyl free radical scavenging capacity. Eucalyptus globulus EO showed a high potential to treat Streptococcus pneumoniae infections. Haemophilus influenzae was the respiratory pathogen that showed the highest resistance to all EOs, including tea tree EO. After 96 h of incubation, at 25 μg/mL, Eucalyptus radiata and Eucalyptus viminalis EOs showed highest cytotoxic activity against the THP-1 cell line. Conclusions: Despite their specific bioactivities, no single EO showed simultaneously good antioxidant, antimicrobial, and antiproliferative activity.

Antioxidant Activity of the Essential Oil and its Major Terpenes of Satureja macrostema (Moc. and Sessé ex Benth.) Briq

BACKGROUND

The aim of this study was to investigate the in vitro antioxidant activity of Satureja macrostema (Moc. and Sessé ex Benth.) Briq. (Lamiaceae) essential oil, a Mexican medicinal plant known as nurite.

MATERIALS AND METHODS

Fresh aerial parts of S. macrostema plants cultivated in greenhouse for 3 months were subjected to hydrodistillation in a Clevenger apparatus to obtain essential oil. Volatile compounds were identified by gas chromatography (GC) and GC/mass spectrometry. Antioxidant effectiveness of essential oil and its major terpenes of S. macrostema was examined by three different radical scavenging methods: 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and total antioxidant capacity (TAC). The concentrations tested were 0.001, 0.01, 0.1, and 1 mg/mL.

RESULTS

The major volatile compounds were caryophyllene, limonene, linalool, pulegone, menthone, and thymol. S. macrostema essential oil showed the highest free radical scavenging activity with DPPH and ABTS methods (53.10% and 92.12%, respectively) at 1 mg/mL and 98% with TAC method at 0.1 mg/mL. Thymol exerted the highest antioxidant capacity with 0.1 mg/mL, reaching 83.38%, 96.96%, and 98.57% by DPPH, ABTS, and TAC methods. Caryophyllene, limonene, linalool, pulegone, and menthone exhibited an antioxidant capacity <25% with the DPPH and ABTS methods; however, limonene showed a TAC of 85.41% with 0.01 mg/mL.

CONCLUSION

The essential oil of S. macrostema and thymol showed a free radical scavenging activity close to that of the synthetic butylated hydroxytoluene.

SUMMARY

The major volatile compounds of essential oil of Satureja macrostema were caryophyllene, limonene, linalool, pulegone, menthone and thymolThe essential oil of S. macrostema showed a high free radical scavengingThymol exerted the highest antioxidant capacity by DPPH, ABTS and TAC methods. Abbreviations used: GC: Gas Chromatography; DPPH: 2,2-diphenyl-1-picrylhydrazyl; ABTS: 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid; TAC: Total antioxidant capacity.

Valorisation of softwood bark through extraction of utilizable chemicals. A review

Softwood bark is an important source for producing chemicals and materials as well as bioenergy. Extraction is regarded as a key technology for obtaining chemicals in general, and valorizing bark as a source of such chemicals in particular. In this paper, properties of 237 compounds identified in various studies dealing with extraction of softwood bark were described. Finally, some challenges and perspectives on the production of chemicals from bark are discussed.

Design and synthesis of coumarin-3-acylamino derivatives to scavenge radicals and to protect DNA

In this study, a series of coumarin-3-acylamino derivatives containing phenethylamine moiety or tyramine moiety were synthesized and their antioxidant activities were evaluated by Cu(2+)/glutathione(GSH)-, ˙OH- and 2,2'-azobis(2-amidinopropane hydrochloride)(AAPH)-induced oxidation of DNA. It was found that both hydroxyl and ortho-methoxy groups at A ring, hydroxyl group at B ring and peptide bond can enhance the abilities of coumarin-3-acylamino derivatives to protect DNA against ˙OH- and AAPH-induced oxidation. Moreover, these coumarin-3-acylamino derivatives were employed to scavenge 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS(+˙)). We found that tyramine moiety, hydroxyl and ortho-methoxy are the key groups to enhance the activities of antioxidants to quench ABTS(+˙). Therefore, tyramine linked with coumarin-3-carboxyl acid which containing hydroxyl and ortho-methoxy exhibited powerful antioxidant abilities.

Steam sauna and mother roasting in Lao PDR: practices and chemical constituents of essential oils of plant species used in postpartum recovery

BACKGROUND

Fundamental in traditional postpartum recovery in Lao PDR is the use of hotbeds, mother roasting, steam sauna and steam baths. During these treatments medicinal plants play a crucial role, but little has been published about how the treatments are carried out precisely, which species are used, the medicinal properties of these species, and the medicinal efficacy of their chemical constituents.

METHODS

Sixty-five interviews, in 15 rural villages, with women of 4 different ethnic groups were conducted to survey confinement rituals, and postpartum plant use and salience. Essential oils from the main species used were extracted using steam distillation and the main chemical constituents characterized using gas chromatography-mass spectrometry (GC-MS).

RESULTS

A total of 10 different species were used by three or more of the ethnic groups included in this study. All species were used in steam sauna and bath, but only 3 species were used in hotbed and mother roasting. Essential oils of Amomum villosum, Amomum microcarpum and Blumea balsamifera were found to contain significant amounts of the following terpenes: β-pinene, camphor, bornyl acetate, borneol, linalool, D-limonene, fenchone, terpinen-4-ol and α-terpinene.

CONCLUSIONS

Many of these terpenes have documented antimicrobial and analgesic properties, and some have also synergistic interactions with other terpenes. The mode of application in hotbed and mother roasting differs from the documented mechanisms of action of these terpenes. Plants in these two practices are likely to serve mainly hygienic purposes, by segregating the mother from infection sources such as beds, mats, stools, cloth and towels. Steam sauna medicinal plant use through inhalation of essential oils vapors can possibly have medicinal efficacy, but is unlikely to alleviate the ailments commonly encountered during postpartum convalescence. Steam sauna medicinal plant use through dermal condensation of essential oils, and steam bath cleansing of the perineal area is possibly a pragmatic use of the reported medicinal plants, as terpene constituents have documented antimicrobial, analgesic and anti-inflammatory properties.

Properties of synthetic homoisoflavonoids to reduce oxidants and to protect linoleic acid and dna against oxidation

3-(2'-, 3'-, and 4'-Hydroxybenzylidene)-7-methoxychroman-4-one (o-, m-, and p-HBMC) was synthesized for the clarification of the influence of the hydroxyl group at the B ring on the antioxidant activity of homoisoflavonoid. The three homoisoflavonoids used herein can reduce peroxynitrite. p-HBMC exhibited high activity to reduce singlet oxygen. Furthermore, o-, m-, and p-HBMC can scavenge the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS(*+)) and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) and galvinoxyl radicals. The rates of o-HBMC trapping of DPPH and galvinoxyl radicals were higher than those of m- and p-HBMC, whereas m-HBMC can trap ABTS(*+) rapidly. o-HBMC was found to possess high activity in the beta-carotene-linoleic acid bleaching test and to protect methyl linoleate against 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH)-induced oxidation efficiently. Finally, o-HBMC served as a prooxidant in Cu(2+)/glutathione (GSH)- and hydroxyl radical-mediated oxidations of DNA. m- and p-HBMC protected DNA against hydroxyl radical-mediated oxidation of DNA effectively, and o- and p-HBMC behaved as antioxidants to protect DNA against AAPH-induced oxidation. Thus, the hydroxyl group attaching to the ortho- and para-positions in the B ring was of importance for the homoisoflavonoid's enhancement of antioxidant activity.

Phenolic and enolic hydroxyl groups in curcumin: which plays the major role in scavenging radicals?

The aim of this work is to clarify the antioxidant abilities of phenolic and enolic hydroxyl groups in curcumin. 1,7-bis(4-benzyloxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione (BEC), 1,7-bis(4-hydroxy-3-methoxyphenyl)heptane-3,5-diol (OHC), 1,7-bis(4-hydroxy-3-methoxyphenyl)heptane-3,5-dione (THC), and 1,7-bis(3,4-dihydroxyphenyl)-1,6-heptadiene-3,5-dione (BDC) are synthesized to determine the antioxidant activities by using antiradical assays against 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical, galvinoxyl radical, and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) cation radical (ABTS*+) and by protecting DNA and erythrocyte against 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH) induced oxidation. The phenolic hydroxyl is the main group for curcumin to trap DPPH, galvinoxyl, and ABTS*+ radicals. The conjugative system between enolic and phenolic hydroxyl groups is beneficial for curcumin to protect erythrocytes against hemin-induced hemolysis and to protect DNA against AAPH-induced oxidation, but is not beneficial for curcumin to protect erythrocytes against AAPH-induced hemolysis. More hydroxyl groups enhance the antioxidant effectiveness of curcumin in the experimental systems employed herein. Therefore, curcumin acts as an antioxidant through the phenolic hydroxyl group.