Chemical composition, antimicrobial activity, and antioxidant capacity of Micromeria flagellaris Baker and M. madagascariensis Baker: Two endemic species from Madagascar as sources of essential oils

Background

The aerial parts of Micromeria madagascariensis Baker and M. flagellaris Baker are used by the population of the Vakinankaratra and Itasy regions (Madagascar) to treat breathing difficulty, fever and/or headache, wounds, and sores.

Purpose

This work aimed to characterise plant materials from M. madagascariensis and M. flagellaris to report i) chemical composition, ii) antimicrobial properties, and iii) antioxidant capacity of the essential oils extracted from the aerial parts of these species.

Materials and methods

The essential oils from M. madagascariensis (MMO) and M. flagellaris (MFO) were obtained by hydrodistillation. Their chemical composition was quantified using gas chromatography coupled with mass spectrometry (GC-MS). MMO and MFO were also tested against 7 microbial strains using the disk diffusion method and their antioxidant capacity was assessed using the DPPH scavenging assay.

Results

Hydrodistillation yielded 0.26% MMO and 0.29% MFO (w/w) in relation to the fresh weight. Twenty-seven compounds were identified by GC-MS in MMO extract against 36 in MFO one. The main compounds in MMO were pulegone (24.67%), trans-menthone (24.67%), eucalyptol (8.12%), β-caryophyllene (4.98%), α-guanene (4.47), iso-menthone (3.85%), iso-pulegone (3.34%), azulene (3.28%) and 2-isopropyl-5-methylcyclohexenone (2.82%). The main compounds in the MFO were eudesma-4,11-dien-2-ol (13.88%), δ-guanene (6.62%), pulegone (6.40%), cyperone (5.56%), 4-epi-dehydrobietinol acetate (5.39%), eucalyptol (5.12%), trans-menthone (4.67%), limonene (3.77%) and sabinene (2.29%). Regarding the chemotaxonomy, M. flagellaris was very different from M. madagascariensis and both species also differed from the other Micromeria species, as confirmed by multivariate statistical analysis. Both MMO and MFO exerted activities against a large microbial spectrum; the antimicrobial activity of MMO was higher than MFO one against S. pneumoniae and C. albicans due to the presence of pulegone as the main component. MFO showed an excellent scavenging capacity with an SC50 value of 2.17 ± 0.03 μg/mL.

Conclusion

The biological properties of the essential oils extracted from the selected species may explain their therapeutic value showing that Malagasy Micromeria species may be very important as new natural sources of bioactive compounds. This study may promote the effectiveness and quality of Malagasy Micromeria species, contributing to sustainable development and commercial valorisation of traditional preparations based on natural local resources.

Determination of polycyclic aromatic hydrocarbons in bud-derived supplements by magnetic molecular imprinted microparticles and GC-MS: D-optimal design for a fast method optimization

Within the world of natural food supplements, organic extracts deriving from young plant meristematic tissue (bud-derivatives) are becoming attractive, thanks to their richness in bioactive molecules. This natural source is scarce, but every year, tons of plant material, including buds, come from city pruning. If this sustainable source is rather promising from a circular economy point of view, the safety of the obtained supplements must be assessed. In fact, anthropic microcontaminants, such as polycyclic aromatic hydrocarbons (PAHs), could adsorb onto the urban buds, leading to a possible contamination of the bud-derivatives. In this study, we developed a magnetic dispersive solid phase extraction (m-dSPE) based on molecularly imprinted microparticles, combined with GC-MS, to quantify the 16 priority PAHs in such extracts. The D-optimal experimental design was implemented to maximize analytes' recovery with the smallest set of experiments. The optimized method was characterized by great selectivity thanks to the molecular imprinted polymer and ease of use provided by m-dSPE. Moreover, it complies with green principles, thanks to the minimum consumption of organic solvent (1.5 mL of acetone per sample). The recoveries ranged from 76 to 100% and procedural precision was below 10% for most PAHs. Despite the matrix complexity, low quantification limits (0.7-12.6 μg kg-1) were reached. This guaranteed the PAHs' quantitation at levels below those indicated as safe by a European Community regulation on food supplements. None of the analyzed samples, coming from different anthropically impacted areas, showed concerning PAHs levels.

Bio-guided isolation of androsta-1,4-dien-3,16-dione as a vasodilator active principle from the inflorescence of Ravenala madagascariensis Sonn. (Strelitziaceae)

Androsta-1,4-dien-3,16-dione was isolated for the first time from the plant kingdom of the ethanolic extract of the Ravenala madagascariensis' inflorescence by the bio-guided method. Its structure was elucidated by NMR and MS spectroscopic data analysis. The vascular effects of ethanol extracts, fractions and androsta-1,4-dien-3,16-dione were assessed on the phenylephrine pre-contracted isolated rat aorta. The isolated compound exerted the most potent vaso-relaxing effect (EC₅₀ = 109.32 ± 15.82 µM) than the ethanol extract and fractions. The pharmacological mechanism of its vaso-relaxing action was analysed on isolated rat aorta using free-endothelial vascular tissue, specific contracting reagents (CaCl₂ and KCl), antagonist (propranolol), enzyme inhibitors (L-NAME, methylene blue) and channel blocker (glibenclamide). Its vaso-relaxing activity could be due, at least partly, to the non-specific inhibition of the calcic influx.

Quali-Quantitative Fingerprinting of the Fruit Extract of Uapaca bojeri Bail. (Euphorbiaceae) and Its Antioxidant, Analgesic, Anti-Inflammatory, and Antihyperglycemic Effects: An Example of Biodiversity Conservation and Sustainable Use of Natural Resources in Madagascar

Antioxidants are important supplements for the human body for their roles in human life for the maintenance of homeostasis. Tapia fruits (Uapaca bojeri) are used by the riverain population of the Tapia forests in Madagascar as complementary foods. This study aims to quantify the main antioxidants in the U. bojeri fruits to verify their contribution to the enhancement of their anti-inflammatory and antihyperglycemic effects. Standard phytochemical screening was used for qualitative analysis, while spectrophotometric (TPC, TAC, and TFC) and chromatographic analyses (HPLC) were used to quantify several phytochemicals in U. bojeri fruits. The antioxidant activity was evaluated using DPPH and FRAP assays. The writhing test was used for the analgesic effects, the carrageenan-induced paw edema was used for the anti-inflammatory activity, and OGTT was used to test the anti-hyperglycemia property of the MEUB in mice. Several phytocompounds were detected and quantified in the fruits, including succinic acid (67.73%) as the main quantified compound. Fruits exerted a good antioxidant capacity and showed analgesic, anti-inflammatory, and antihyperglycemic activities in mice. Isolation of the bioactive compounds should be carried out to confirm these pharmacological properties and develop health-promoting food products or medicinal applications derived from this species.

Vitis vinifera L. Pruning Waste for Bud-Preparations as Source of Phenolic Compounds–Traditional and Innovative Extraction Techniques to Produce New Natural Products

Herbal products are now considered among the most important sources of phenolic compounds: the FINNOVER project aimed at the creation and development of sustainable supply chains to extract and use natural biologically active agents. Vitis vinifera is one of the most utilised herbal products derived from buds and sprouts as polyphenolic food supplements for its homeostatic and astringent properties. This research was aimed to describe the antioxidant capacity and the phytochemical composition of V. vinifera herbal products by the application of spectroscopic and chromatographic fingerprints considering phenolics as potential markers to significantly differentiate traditional preparations (macerates) from innovative extracts obtained by an ultrasound extraction from V. vinifera buds. Two different commercial products were also considered. Flavonols were the most abundant class in ultrasound extracts (45%), while phenolic acids were the most important class in traditional macerates (49%) and commercial bud-preparations (about 50%). This study may support the potential use of V. vinifera bud-products (starting from pruning byproducts) as food supplements to integrate human diet with good amounts of phenolics. Finally, the use of different extraction methods on the same plant material could be an important development to produce innovative herbal products with a phytochemical composition similar to traditional preparations.

Advances in Rootstock Breeding of Nut Trees: Objectives and Strategies

The production and consumption of nuts are increasing in the world due to strong economic returns and the nutritional value of their products. With the increasing role and importance given to nuts (i.e., walnuts, hazelnut, pistachio, pecan, almond) in a balanced and healthy diet and their benefits to human health, breeding of the nuts species has also been stepped up. Most recent fruit breeding programs have focused on scion genetic improvement. However, the use of locally adapted grafted rootstocks also enhanced the productivity and quality of tree fruit crops. Grafting is an ancient horticultural practice used in nut crops to manipulate scion phenotype and productivity and overcome biotic and abiotic stresses. There are complex rootstock breeding objectives and physiological and molecular aspects of rootstock-scion interactions in nut crops. In this review, we provide an overview of these, considering the mechanisms involved in nutrient and water uptake, regulation of phytohormones, and rootstock influences on the scion molecular processes, including long-distance gene silencing and trans-grafting. Understanding the mechanisms resulting from rootstock × scion × environmental interactions will contribute to developing new rootstocks with resilience in the face of climate change, but also of the multitude of diseases and pests.

Endophytic Fungi and Ecological Fitness of Chestnuts

Chestnuts (Castanea spp.) are plants of relevant economic interest in the agro-sylvicultural contexts of mountain regions throughout the temperate zone, particularly in the northern hemisphere. In recent years, several biological adversities have repeatedly endangered species belonging to this genus, calling for coordinated actions addressed to contrast their decline. These actions have mainly focused on the control of key pests/pathogens and the improvement of resistance/tolerance by the plant host, while the role of microorganisms as mediators of interactions between plants and the noxious agents has been less considered, essentially by reason of a limited knowledge on their ecological impact. In line with the increasing awareness of the basic importance of microbial symbionts in regulating plant fitness in both natural and crop contexts, this paper offers an overview on the occurrence and effects of endophytic fungi of chestnuts.

Analytical Strategies for Fingerprinting of Antioxidants, Nutritional Substances, and Bioactive Compounds in Foodstuffs Based on High Performance Liquid Chromatography-Mass Spectrometry: An Overview

New technology development and globalisation have led to extreme changes in the agri-food sector in recent years that need an important food supply chain characterisation from plant materials to commercial productions. Many analytical strategies are commonly utilised in the agri-food industry, often using complementary technologies with different purposes. Chromatography on-line coupled to mass spectrometry (MS) is one of the most selective and sensitive analytical methodologies. The purpose of this overview is to present the most recent MS-based techniques applied to food analysis. An entire section is dedicated to the recent applications of high-resolution MS. Covered topics include liquid (LC)– and gas chromatography (GC)–MS analysis of natural bioactive substances, including carbohydrates, flavonoids and related compounds, lipids, phenolic compounds, vitamins, and other different molecules in foodstuffs from the perspectives of food composition, food authenticity and food adulteration. The results represent an important contribution to the utilisation of GC–MS and LC–MS in the field of natural bioactive compound identification and quantification.

Bud-Derivatives, a Novel Source of Polyphenols and How Different Extraction Processes Affect Their Composition

The use of herbal food supplements, as a concentrate form of vegetable extracts, increased so much over the past years to count them among the relevant sources of dietetic polyphenols. Bud-derivatives are a category of botanicals perceived as a "new entry" in this sector since they are still poorly studied. Due to the lack of a manufacturing process specification, very different products can be found on the market in terms of their polyphenolic profile depending on the experimental conditions of manufacturing. In this research two different manufacturing processes, using two different protocols, and eight species (Carpinus betulus L., Cornus mas L., Ficus carica L., Fraxinus excelsior L., Larix decidua Mill., Pinus montana Mill., Quercus petraea (Matt.) Liebl., Tilia tomentosa Moench), commonly used to produce bud-derivatives, have been considered as a case study. An untargeted spectroscopic fingerprint of the extracts, coupled to chemometrics, provide to be a useful tool to identify these botanicals. The targeted phytochemical fingerprint by HPLC provided a screening of the main bud-derivatives polyphenolic classes highlighting a high variability depending on both method and protocol used. Nevertheless, ultrasonic extraction proved to be less sensitive to the different extraction protocols than conventional maceration regarding the extract polyphenolic profile.

Antioxidant, Anti-Inflammatory, and Antidiabetic Activities of Leaves and Stems of Uapaca bojeri Bail. (EUPHORBIACEAE), an Endemic Plant of Madagascar

Uapaca bojeri is an endemic Malagasy plant used by the local population. This work aimed to evaluate antioxidant, anti-inflammatory, and antidiabetic activities of the methanol extracts of U. bojeri leaves and stems and to report their total phenolic content and the bioactive compound content by HPLC methods. Antioxidant capacity was determined by DPPH and ferric reducing antioxidant power (FRAP) assays. An in vivo carrageenan-induced paw oedema and acetic acid-induced writhing test in mice were used for anti-inflammatory activity evaluation. An oral glucose tolerance test was performed in mice to evaluate antidiabetic activity. The total bioactive compound content of leaves was higher than that of stems. Stem methanol extract inhibited the free radical DPPH more than the leaf methanol extract. Leaf methanol extract inhibited, in a dose-dependent manner, the carrageenan-induced paw oedema more than the stem extract, but their inhibition of the pain symptoms caused an acetic acid-induced decrease similar to the number of writhes in the dose-dependent case. The leaf and stem methanol extracts significantly reduced blood glucose levels after 30 min of glucose loading in mice compared to the control group blood glucose reduction. The presence of several bioactive compounds in U. bojeri contributed to the different biological activities, but isolation and identification of these bioactive molecules are necessary to confirm these pharmacological properties.

First ethnobotanical inventory and phytochemical analysis of plant species used by indigenous people living in the Maromizaha forest, Madagascar

ETHNOPHARMACOLOGICAL RELEVANCE

Characterized by one of the highest rates of endemism and biodiversity in the world, Madagascar provides a wide variety of medicinal plants, that could represent a potential source of new drugs. The main aim of this study was to investigate the potential medicinal properties of the plant species used by indigenous people in Maromizaha forest and to provide the first ethnobotanical inventory of the area.

MATERIALS AND METHODS

Data were collected through open semi-structured interviews with local informants, the reported plants were collected and identified to create a specimen herbarium. Informant Consensus Factor (ICF) was calculated for each ailment category mentioned in the use-reports. A selection of seven medicinal plants was submitted to phytochemical and antimicrobial analysis. The results were discussed and compared with those described in ethnobotanical and pharmacological literature.

RESULTS

One hundred and three villagers were interviewed and a total of 509 use-reports were recorded. Information on 117 plant species belonging to 57 botanical families were provided. 12 categories of indigenous uses were recognized, among them the higher ICF values were recorded for cardiovascular complaints (0.75), general and unspecific diseases (0.74), digestive disorders (0.69), and diseases of the skin (0.55). The traditional medicinal uses of 18 species (15 endemic) were described for the first time. In total, 22 different bioactive compounds were identified; polyphenols, monoterpenes, organic acids, and vitamin C were observed in the chemical composition of all the analyzed samples. Macaranga perrieri showed the highest values of both total polyphenolic compounds and antioxidant activity. Antimicrobial activity was observed in leaf and bark extracts of Dilobeia thouarsii.

CONCLUSION

These results confirmed the importance of investigating the traditional use of plant species, suggesting the crucial role of ethnobotanical studies for rural development, biodiversity conservation, and the sustainable use of plant resources in the studied area.

Assessing Nutritional Traits and Phytochemical Composition of Artisan Jams Produced in Comoros Islands: Using Indigenous Fruits with High Health-Impact as an Example of Biodiversity Integration and Food Security in Rural Development

In the Comoros Islands, as in other developing countries, malnutrition and food insecurity affect a very large percentage of the population. Developing fruit-based products in order to make profit, reduce poverty and improve indigenous people diet could be very important for local population of countries as Comoros Islands. The aim of the present work was to study the chemical composition of jams and jellies produced from seven fruit species harvested in Grand Comore Island. The following parameters were studied sugars and organic acids, total phenolics, total anthocyanins and high-performance liquid chromatography (HPLC) fingerprint of the main phytochemicals. Antioxidant activity was also measured. A multivariate approach (Principal Component Analysis) was performed in order to better characterize the products and to set a potential analytical tool for jam characterisation. Results showed that the analysed products are a good source of polyphenolic constituents, as caffeic and gallic acids, catechin and quercetin and volatile compounds, as limonene and γ-terpinene: these molecules may be considered as suitable markers for these fruit-derived products as characterizing the chromatographic patterns. The characterisation of these products and their nutritional and nutraceutical traits is important as valorisation of local food production for poverty reduction and rural development. Further benefits of this approach include the maintenance of local agro-biodiversity as raw material for fruit-based products and the strengthening of food security practices.

New Findings in Prunus padus L. Fruits as a Source of Natural Compounds: Characterization of Metabolite Profiles and Preliminary Evaluation of Antioxidant Activity

European bird cherry (Prunus padus L.) has been known since the Middle Ages for its medical/food use and high health-promoting value. This study aimed to assess the potential of these fruits as a source of bioactive compounds through the characterization of its physicochemical traits, nutraceutical properties, phytochemical composition via HPLC fingerprint, and antioxidant capacity. Fully ripened fruits of Prunus padus L. (Colorata cv) were collected in mid-July 2017 in Chieri, north-western Italy. The TPC (194.22 ± 32.83 mgGAE/100 gFW) and TAC (147.42 ± 0.58 mgC3G/100 gFW) values were obtained from the analyzed extracts. The most important phytochemical class was organic acids (48.62 ± 2.31%), followed by polyphenols (35.34 ± 1.80%), monoterpenes (9.36 ± 0.64%), and vitamin C (6.68 ± 0.22%). In this research the most important flavonols selected as marker were quercitrin (16.37 ± 3.51 mg/100 gFW) and quercetin (11.86 ± 2.36 mg/100 gFW). Data were reported based on fresh weight. Moreover, fresh fruits showed a mean antioxidant activity value of 17.78 ± 0.84 mmol Fe2+·kg-1. Even though the seeds and leaves contain cyanogenic glycosides, this study showed that these fruits could be a natural source of bioactive compounds with high antioxidant properties, due to the contents of organic and phenolic acids, catechins, and a synergetic effect of vitamin C and flavonoids.

Nutraceuticals in Alternative and Underutilized Fruits as Functional Food Ingredients: Ancient Species for New Health Needs

A diet containing high levels of fruit has been associated with a lowered risk of chronic diseases as, in addition to their vitamin and mineral content, they also contain various compounds with health-protective effects, in particular antioxidant and antiinflammatory compounds. Wild plant species are of interest to the food industry because of their ability to replace synthetic chemicals and nutraceuticals; however, the nutritional, economical, and sociocultural values of some neglected and underutilized natural resources have not yet been fully exploited. Some of these less well-known and underutilized fruits, which have the potential to provide novel sources of health-promoting agents, are presented in this chapter (i.e., Asimina triloba (L.) Dunal, Crataegus azarolus L., Lycium barbarum L., Morus nigra L., and Amelanchier canadensis (L.) Medicus). Underutilized fruits could represent an opportunity for growers to gain access to these special markets where consumers place emphasis on high contents of nutrients that are capable of preventing degenerative diseases. The development of specific horticultural models for nutraceutical fruit production could be an interesting opportunity to obtain a highly standardized raw material for fresh or derived products.

Serviceberry, a berry fruit with growing interest of industry: Physicochemical and quali-quantitative health-related compound characterisation

Amelanchier canadensis (L.) Medik., commonly called serviceberry, is a potential functional food that is also used for its medicinal purposes. This work evaluated the potential of a cultivated serviceberry species as a functional food by characterising its physicochemical characteristics, antioxidant capacity, vitamin C, phenolics and other phytochemicals selected as health-promoting biomarkers, using high-performance liquid chromatography. The most important compound class identified was polyphenols (62.10%), followed by organic acids (22.63%), monoterpenes (7.95%), and vitamins (7.32%). Results showed that serviceberry fruits could be good sources of phenolic constituents, as catechins (343.46 ± 29.46 mg/100 g_FW), anthocyanins (220.66 ± 17.43 mg/100 g_FW), and tannins (209.29 ± 7.81 mg/100 g_FW) (FW = fresh weight). These results highlight the potential role of A. canadensis fruits as a functional food. Further studies are needed to identify several genotypes for breeding to get suitable cultivars for fresh consumption and processing.

Biomolecules and Natural Medicine Preparations: Analysis of New Sources of Bioactive Compounds from Ribes and Rubus spp. Buds

It is well known that plants are important sources for the preparation of natural remedies as they contain many biologically active compounds. In particular, polyphenols, terpenic compounds, organic acids, and vitamins are the most widely occurring groups of phytochemicals. Some endemic species may be used for the production of herbal preparations containing phytochemicals with significant bioactivity, as antioxidant activity and anti-inflammatory capacities, and health benefits. Blackberry sprouts and blackcurrant buds are known to contain appreciable levels of bioactive compounds, including flavonols, phenolic acids, monoterpenes, vitamin C, and catechins, with several clinical effects. The aim of this research was to perform an analytical study of blackcurrant and blackberry bud-preparations, in order to identify and quantify the main biomarkers, obtaining a specific phytochemical fingerprint to evaluate the single botanical class contribution to total phytocomplex and relative bioactivity, using a High Performance Liquid Chromatograph−Diode Array Detector; the same analyses were performed both on the University laboratory and commercial preparations. Different chromatographic methods were used to determine concentrations of biomolecules in the preparations, allowing for quantification of statistically significant differences in their bioactive compound content both in the case of Ribes nigrum and Rubus cultivated varieties at different harvest stages. In blackcurrant bud-extracts the most important class was organic acids (50.98%) followed by monoterpenes (14.05%), while in blackberry preparations the main bioactive classes were catechins (50.06%) and organic acids (27.34%). Chemical, pharmaceutical and agronomic-environmental knowledge could be important for obtaining label certifications for the valorization of specific genotypes, with high clinical and pharmaceutical value: this study allowed to develop an effective tool for the natural preparation quality control and bioactivity evaluation through the chemical fingerprinting of bud preparations.

Castanea spp. buds as a phytochemical source for herbal preparations: botanical fingerprint for nutraceutical identification and functional food standardisation

BACKGROUND

Many plant species may be used for the production of herbal preparations containing phytochemicals with significant antioxidant and anti-inflammatory capacities and health benefits: Castanea spp. is among the most commonly used herbal medicines. The aim of this research was to perform an analytical study of chestnut bud preparations, in order to identify and quantify the main bioactive compounds, and to obtain a specific chemical fingerprint to evaluate the single class contribution to the herbal preparation phytocomplex. The analyses were performed using a high-performance liquid chromatograph coupled to a diode array detector.

RESULTS

Castanea spp. was identified as a rich source of anti-inflammatory and antioxidant compounds: the observed analytical fingerprint demonstrated that these bud preparations represent a rich source of bioactive compounds (104.77 ± 1.14 g kg(-1) FW) in relation to different genotypes, specific sampling sites and several phenological stages.

CONCLUSION

This study showed that the observed analytical fingerprint can be considered an important tool for assessing the chemical composition and bioactivities of the chestnut-derived products, considering the Castanea genus as a new source of natural health-promoting compounds. This study allowed the development of an effective tool for quality control by fingerprinting the bud preparation in order to develop a new generation of standardised preparations.

Botanicals in Ribes nigrum bud-preparations: an analytical fingerprinting to evaluate the bioactive contribution to total phytocomplex

CONTEXT. Ribes nigrum L. (Grossulariaceae) is among the most commonly used herbal medicines and it is popularized for its alleged tonic effect and curative and restorative properties. The current practice of identifying herbal extracts is by measuring the concentration of the main botanicals. Their concentrations are used to characterize the herbal preparations and fingerprinting is recommended by the main Pharmacopeias as a potential and reliable strategy for the quality control of complex mixtures.

OBJECTIVE

The aim of this research was to perform an analytical study of R. nigrum bud-preparations, in order to identify and quantify the main bioactive compounds, obtaining a specific chemical fingerprint to evaluate the single class contribution to herbal preparation phytocomplex.

MATERIALS AND METHODS

The same analyses were performed using a high-performance liquid chromatograph-diode array detector both on University lab preparations and on commercial preparations from different Italian locations. Different chromatographic methods were used to analyse the macerated samples, two for polyphenols and one for terpenic compounds. RESULTS. Ribes nigrum was identified as a rich source of anti-inflammatory and antioxidant compounds. The observed analytical firgerprint demonstrated that these bud-preparations represent a rich source of terpenic and polyphenolic compounds, especially catechins and phenolic acids.

DISCUSSION AND CONCLUSION

Analytical fingerprinting could be an important tool to study the assessment of chemical composition and bioactivities of plant-derived products, helping to find new sources of natural health-promoting compounds: this study allowed the development of an effective tool for quality control through botanical fingerprinting of bud preparations.