Showing papers in "Phytochemistry Reviews in 2022"

Production of microalgae with high lipid content and their potential as sources of nutraceuticals

Abstract: In the current global scenario, the world is under a serious dilemma due to the increasing human population, industrialization, and urbanization. The ever-increasing need for fuels and increasing nutritional problems have made a serious concern on the demand for nutrients and renewable and eco-friendly fuel sources. Currently, the use of fossil fuels is creating ecological and economic problems. Microalgae have been considered as a promising candidate for high-value metabolites and alternative renewable energy sources. Microalgae offer several advantages such as rapid growth rate, efficient land utilization, carbon dioxide sequestration, ability to cultivate in wastewater, and most importantly, they do not participate in the food crop versus energy crop dilemma or debate. An efficient microalgal biorefinery system for the production of lipids and subsequent byproduct for nutraceutical applications could well satisfy the need. But, the current microalgal cultivation systems for the production of lipids and nutraceuticals do not offer techno-economic feasibility together with energy and environmental sustainability. This review article has its main focus on the production of lipids and nutraceuticals from microalgae, covering the current strategies used for lipid production and the major high-value metabolites from microalgae and their nutraceutical importance. This review also provides insights on the future strategies for enhanced microalgal lipid production and subsequent utilization of microalgal biomass.

Propolis: chemical diversity and challenges in quality control

Abstract: Propolis is a resinous natural product produced by honeybees using beeswax and plant exudates. The chemical composition of propolis is highly complex, and varies with region and season. This inherent chemical variability presents several challenges to its standardisation and quality control. The present review was aimed at highlighting marker compounds for different types of propolis, produced by the species Apis mellifera, from different geographical origins and that display different biological activities, and to discuss strategies for quality control. Over 800 compounds have been reported in the different propolises such as temperate, tropical, birch, Mediterranean, and Pacific propolis; these mainly include alcohols, acids and their esters, benzofuranes, benzopyranes, chalcones, flavonoids and their esters, glycosides (flavonoid and diterpene), glycerol and its esters, lignans, phenylpropanoids, steroids, terpenes and terpenoids. Among these, flavonoids (> 140), terpenes and terpenoids (> 160) were major components. A broad range of biological activities, such as anti-oxidant, antimicrobial, anti-inflammatory, immunomodulatory, and anticancer activities, have been ascribed to propolis constituents, as well as the potential of these compounds to be biomarkers. Several analytical techniques, including non-separation and separation methods have been described in the literature for the quality control assessment of propolis. Mass spectrometry coupled with separation methods, followed by chemometric analysis of the data, was found to be a valuable tool for the profiling and classification of propolis samples, including (bio)marker identification. Due to the rampant chemotypic variability, a multiple-marker assessment strategy considering geographical and biological activity marker(s) with chemometric analysis may be a promising approach for propolis quality assessment.The online version contains supplementary material available at 10.1007/s11101-022-09816-1.

Flavonoid mediated selective cross-talk between plants and beneficial soil microbiome

Abstract: Plants generate a wide variety of organic components during their different growth phases. The majority of those compounds have been classified as primary and secondary metabolites. Secondary metabolites are essential in plants' adaptation to new changing environments and in managing several biotic and abiotic stress. It also invests some of its photosynthesized carbon as secondary metabolites to establish a mutual relationship with soil microorganisms in that specific niche. As soil harbors both pathogenic and beneficial microorganisms, it is essential to identify some specific metabolites that can discriminate beneficial and pathogenic ones. Thus, a detailed understanding of metabolite's architectures that interact with beneficial microorganisms could open a new horizon of ecology and agricultural research. Flavonoids are used as classic examples of secondary metabolites in this study to demonstrate recent developments in understanding and realizing how these valuable metabolites can be controlled at different levels. Most of the research was focused on plant flavonoids, which shield the host plant against competitors or predators, as well as having other ecological implications. Thus, in the present review, our goal is to cover a wide range of functional and signalling activities of secondary metabolites especially, flavonoids mediated selective cross-talk between plant and its beneficial soil microbiome. Here, we have summarized recent advances in understanding the interactions between plant species and their rhizosphere microbiomes through root exudates (flavonoids), with a focus on how these exudates facilitate rhizospheric associations.The online version contains supplementary material available at 10.1007/s11101-022-09806-3.

Sustainable microalgal biomass production in food industry wastewater for low-cost biorefinery products: a review

Abstract: Microalgae are recognized as cell factories enriched with biochemicals suitable as feedstock for bio-energy, food, feed, pharmaceuticals, and nutraceuticals applications. The industrial application of microalgae is challenging due to hurdles associated with mass cultivation and biomass recovery. The scale-up production of microalgal biomass in freshwater is not a sustainable solution due to the projected increase of freshwater demands in the coming years. Microalgae cultivation in wastewater is encouraged in recent years for sustainable bioeconomy from biorefinery processes. Wastewater from the food industry is a less-toxic growth medium for microalgal biomass production. Traditional wastewater treatment and management processes are expensive; hence it is highly relevant to use low-cost wastewater treatment processes with revenue generation through different products. Microalgae are accepted as potential biocatalysts for the bioremediation of wastewater. Microalgae based purification of wastewater technology could be a universal alternative solution for the recovery of resources from wastewater for low-cost biomass feedstock for industry. This review highlights the importance of microalgal biomass production in food processing wastewater, their characteristics, and different microalgal cultivation methods, followed by nutrient absorption mechanisms. Towards the end of the review, different microalgae biomass harvesting processes with biorefinery products, and void gaps that tend to hinder the biomass production with future perspectives will be intended. Thus, the review could claim to be valuable for sustainable microalgae biomass production for eco-friendly bioproduct conversions.

Anti-viral triterpenes: a review

Abstract: Triterpenes are naturally occurring derivatives biosynthesized following the isoprene rule of Ruzicka. The triterpenes have been reported to possess a wide range of therapeutic applications including anti-viral properties. In this review, the recent studies (2010–2020) concerning the anti-viral activities of triterpenes have been summarized. The structure activity relationship studies have been described as well as brief biosynthesis of these triterpenes is discussed.

Valorisation of algal biomass to value-added metabolites: emerging trends and opportunities

Abstract: Algal biomass is a promising feedstock for sustainable production of a range of value-added compounds and products including food, feed, fuel. To further augment the commercial value of algal metabolites, efficient valorization methods and biorefining channels are essential. Algal extracts are ideal sources of biotechnologically viable compounds loaded with anti-microbial, anti-oxidative, anti-inflammatory, anti-cancerous and several therapeutic and restorative properties. Emerging technologies in biomass valorisation tend to reduce the significant cost burden in large scale operations precisely associated with the pre-treatment, downstream processing and waste management processes. In order to enhance the economic feasibility of algal products in the global market, comprehensive extraction of multi-algal product biorefinery is envisaged as an assuring strategy. Algal biorefinery has inspired the technologists with novel prospectives especially in waste recovery, carbon concentration/sequestration and complete utilisation of the value-added products in a sustainable closed-loop methodology. This review critically examines the latest trends in the algal biomass valorisation and the expansive feedstock potentials in a biorefinery perspective. The recent scope dynamics of algal biomass utilisation such as bio-surfactants, oleochemicals, bio-stimulants and carbon mitigation have also been discussed. The existing challenges in algal biomass valorisation, current knowledge gaps and bottlenecks towards commercialisation of algal technologies are discussed. This review is a comprehensive presentation of the road map of algal biomass valorisation techniques towards biorefinery technology. The global market view of the algal products, future research directions and emerging opportunities are reviewed.

Hydrolates: a review on their volatiles composition, biological properties and potential uses

Abstract: An hydrolate (also known as hydrosol, floral water, aromatic water, or herbal water) is a distillate which is a product of condensation obtained after an essential oil distillation isolation procedure. Hydrolates are colloidal suspensions composed of a continuous phase, the distilled water, and a dispersed phase, the emulsion of essential oil droplets and water-soluble components, namely oxygen-containing compounds. The movement towards a circular economy, has increased the interest in the essential oil industry co-products, such as hydrolates. Hydrolates composition were mostly studied based on their volatile constituents. Moreover, they showed a diverse range of biological properties, with potential application in food, beverages, cosmetic and pharmaceutical industries, as well as in the agroforest sector. Nevertheless, the information is fragmented and dispersed under the different hydrolates designations. In the present review, the main volatile components of 362 hydrolates obtained from 194 species from 50 families is described, and the information on the corresponding essential oil main components is detailed. Additionally, the methodologies of extraction and analysis are surveyed, as well as hydrolates characteristics and traditional uses. This review also describes the different biological properties attributed to hydrolates and, according with these properties, their potential uses.

Biological properties and potential of compounds extracted from red seaweeds

Abstract: Macroalgae have been recently used for different applications in the food, cosmetic and pharmaceutical industry since they do not compete for land and freshwater against other resources. Moreover, they have been highlighted as a potential source of bioactive compounds. Red algae (Rhodophyta) are the largest group of seaweeds, including around 6000 different species, thus it can be hypothesized that they are a potential source of bioactive compounds. Sulfated polysaccharides, mainly agar and carrageenans, are the most relevant and exploited compounds of red algae. Other potential molecules are essential fatty acids, phycobiliproteins, vitamins, minerals, and other secondary metabolites. All these compounds have been demonstrated to exert several biological activities, among which antioxidant, anti-inflammatory, antitumor, and antimicrobial properties can be highlighted. Nevertheless, these properties need to be further tested on in vivo experiments and go in-depth in the study of the mechanism of action of the specific molecules and the understanding of the structure-activity relation. At last, the extraction technologies are essential for the correct isolation of the molecules, in a cost-effective way, to facilitate the scale-up of the processes and their further application by the industry. This manuscript is aimed at describing the fundamental composition of red algae and their most studied biological properties to pave the way to the utilization of this underused resource.

Hepatoprotective potential of selected medicinally important herbs: evidence from ethnomedicinal, toxicological and pharmacological evaluations

Abstract: Abstract Medicinal herbs are nature’s gift to humanity, contributing crucially to the preservation, maintenance and improvement of our health. In order to explore the hepatoprotective potential of prevalent medicinal plants, nine species were selected from different genera based on their ethnomedicinal records in treating different liver-related pathological conditions in South Asia. Besides, the available information was critically analyzed to gain new insights and directions for future investigations towards establishing such natural products as potent hepatoprotective agents or dietary supplements. The hepatoprotective activities of the species have been investigated in a wide variety of in vivo experimental models including carbon tetrachloride-, paracetamol-, iron-, mercuric chloride-, thioacetamide-, cyclophosphamide-, β- d -galactosamine-, cumene hydroperoxide-, α-naphthyl-isothiocyanate-, physical stress- and alcohol-induced hepatotoxicity in rats and mice. All the plants were consistent in their ability to possess hepatoprotective properties. As well, three bioactive isolates namely, schaftoside, echinocystic acid, and eclalbasaponin II were found to have promising hepatoprotective potential. However, extensive comparative studies are warranted in future to establish the relative hepatoprotective potentials of the nine species under discussion. Preparation of poly-herbal formulations from these plants and identification of hepatoprotective phytoconstituents from these plants might open up new avenues in the development of therapeutic hepatoprotective agents.

Amomum tsao-ko Crevost & Lemarié: a comprehensive review on traditional uses, botany, phytochemistry, and pharmacology

Abstract: Tsaoko Fructus, the dried ripe fruit of Amomum tsao-ko Crevost & Lemarié, is used as both medicinal material and food additive. This review summarized the traditional uses, botany, phytochemistry, and pharmacological progress on Tsaoko Fructus. One classical prescription and the other 11 representative prescriptions containing Tsaoko Fructus were reviewed. The indications of these prescriptions are major in treating spleen and stomach disorders and epidemic febrile diseases including malaria. At least 209 compounds have been isolated and identified from Tsaoko Fructus, most of which belong to terpenoids, phenylpropanoids, and organic acids. Essential oil, crude extract, and some compounds were observed to have pharmacological activities such as anti-biotics, anti-inflammation, antioxidant, mostly via in vitro experiments. However, the mechanism of its medicinal uses remains unclear. This review provides a comprehensive understanding of Tsaoko Fructus, which will be beneficial to exploring the mechanism and potential medicinal applications of Tsaoko Fructus, as well as developing a rational quality control system for Tsaoko Fructus as a medicinal material in the future.The online version contains supplementary material available at 10.1007/s11101-021-09793-x.

Seasonal variations of natural products in European herbs

Abstract: Abstract The present review gives an overview about the status of research on seasonal variation of natural products in herbs growing in or grown in Europe. Due to pronounced differences in weather patterns, papers covering plants from the Mediterranean, the temperate, and the cold climate zones are reviewed separately. Apart from trying to give an overview of the existing newer literature after the year 2000, we try to identify some repeatedly found seasonal trends and discuss some possible explanations for these trends. Moreover, some suggestions, which encompass both research bias and desirable quality standards concerning experimental designs for future studies, are given. The covered investigations are mainly focused on aerial parts and leaves. Some publications are also dealing with flowers and roots. The composition of essential oils of aromatic plants are particularly well investigated. Phenolics are the most often studied compound class, including different types of phenolic acids, flavonoids, and tannins. Additionally, some papers assess the seasonal variation of alkaloids and lipophilic compounds.

Stimulating secondary compound accumulation by elicitation: Is it a realistic tool in medicinal plants in vivo?

Abstract: Abstract Stimulating the production of secondary metabolites by elicitation seems to be an accepted tool in several in vitro cultures. In vivo application of chemical elicitation is, however, much less frequently discussed. The paper summarizes the experimental findings on the effects of jasmonic acid, methyl-jasmonate (MeJa) and salicylic acid (SA) treatments on medicinal and aromatic plants. Growth behaviour, yield, stress responses, essential oil (EO) and phenolic compounds are discussed. Exogenous application of MeJa or SA mostly by foliar spraying in concentrations between 10 −4 and 4 mM, induced various changes in the plants. In most cases, the elicitation enhanced the volatile accumulation, although the opposite reaction was observed too. Numerous in vivo trials also demonstrated an altered EO composition. Positive effects of treatments on the concentration of phenolic type compounds were described, while in some cases the components exhibited contradictory behavior or no significant changes. Unfortunately, phenolic composition was rarely determined. There is evidence for the dose dependency of the reactions to both elicitors, but systematic studies on this issue are missing. Some results indicate that lower concentrations in replication may be at least as effective as higher ones. Changes in secondary metabolite accumulation may be induced by the elicitors directly or through other physiological processes. The in vivo results should be considered in the complex system of plant ontogenesis, environmental conditions, timing of the treatment, type of the elicitor and concentration. Research results indicate a promising aspect of chemical elicitation in vivo , but further well-designed studies are needed for the individual species.

Strategies for the synthesis of canonical, non-canonical and analogues of strigolactones, and evaluation of their parasitic weed germination activity

Abstract: Abstract Strigolactones (SLs) are natural products with promising applications as agrochemicals to prevent infestation with parasitic weeds due to their ability to trigger seed germination. However, their use is still limited because of the low yields in which they are isolated from natural sources. As such, numerous studies have led to strategies for obtaining them, and various structural analogues, by organic synthesis. These analogues have focused attention on the study of SLs, as some of them are easier to synthesize and possess enhanced properties, such as the level of bioactivity. This review provides an overview of the synthesis of SLs, subsequently focusing on the production of analogues with the canonical structure. The germinating activity of the compounds is also described herein, with positive effects on different species of the problematic genera Striga , Orobanche and Phelipanche having been found. The highly active analogue GR24 is currently the most widely studied in the literature, and relevant structural-activity relationships have been proposed as a result of the study of derivatives functionalized in different positions. Analogues based on other natural SLs such as strigol and orobanchol have also been developed, as have some novel canonical SLs derived from eudesmanolide or guaianolide sesquiterpene lactones. This review aims to provide useful information for the development of bioactive compounds applicable in new generation herbicides, in an attempt to employ similar compounds to those produced naturally in ecosystems that provoke effective herbicide effects at low concentrations.

Phytochemistry and pharmacology of sea buckthorn (Elaeagnus rhamnoides; syn. Hippophae rhamnoides): progress from 2010 to 2021

Abstract: Sea buckthorn (Elaeagnus rhamnoides; syn. Hippophae rhamnoides) is a thorny shrub or a small tree belonging to the Elaeagnaceae family, native to Eurasia. Sea buckthorn fruit is rich in vitamins and minerals, oils from the seeds and fruit flesh find use in medicine and the cosmetic industry or as nutraceutical supplements. Fruit, leaves and other parts of buckthorn have been used in traditional medicine, especially in China, Tibet, Mongolia, and Central Asia countries, and are a rich source of many bioactive substances. Due to its health-promoting and medicinal properties, the plant has been extensively investigated for several decades, and its phytochemical composition and pharmacological properties are well characterized. The years 2010-2021 brought significant progress in phytochemical research on sea buckthorn. Dozens of new compounds, mainly phenolics, were isolated from this plant. Numerous pharmacological studies were also performed, investigating diverse aspects of the biological activity of different extracts and natural products from sea buckthorn. This review focuses on the progress in research on sea buckthorn specialized metabolites made in this period. Pharmacological studies on sea buckthorn are also discussed. In addition, biosynthetic pathways of the main groups of these compounds have been shortly described.

Momordica balsamina: phytochemistry and pharmacological potential of a gifted species

Abstract: Momordica balsamina L. (Cucurbitaceae), frequently named balsam apple, southern balsam pear or African pumpkin, is a vegetable with high nutritional value, being mostly used as food in sub-Saharan Africa. It has also been largely used in traditional medicine to treat several diseases, such as malaria fevers and diabetes. As a member of the Cucurbitaceae family, the main constituents are cucurbitane-type triterpenoids, with different oxidation patterns, named cucurbitacins. This review aims at summarizing our contribution to the phytochemical study of M. balsamina and the evaluation of the isolated cucurbitacins and derivatives as multidrug resistance reversers in cancer cells and bacteria. In this way, the selective antiproliferative activity against multidrug resistant cancer cells of cucurbitacins obtained from M. balsamina, their ability as P-glycoprotein inhibitors in cancer cells overexpressing this ABC transporter, as well as efflux pump inhibitors in resistant bacteria strains are reviewed. Moreover, the in vitro antimalarial activity of cucurbitacins and acyl derivatives against the blood and liver-stages of Plasmodium strains, and the in vivo activity of selected compounds is also reviewed. Besides our work, edible and medicinal uses, and other studies mainly reporting the biological activities of M. balsamina extracts, such as antidiabetic, antibacterial, anti-inflammatory, and antioxidant properties are also addressed.

Momordica balsamina: phytochemistry and pharmacological potential of a gifted species

Abstract: Momordica balsamina L. (Cucurbitaceae), frequently named balsam apple, southern balsam pear or African pumpkin, is a vegetable with high nutritional value, being mostly used as food in sub-Saharan Africa. It has also been largely used in traditional medicine to treat several diseases, such as malaria fevers and diabetes. As a member of the Cucurbitaceae family, the main constituents are cucurbitane-type triterpenoids, with different oxidation patterns, named cucurbitacins. This review aims at summarizing our contribution to the phytochemical study of M. balsamina and the evaluation of the isolated cucurbitacins and derivatives as multidrug resistance reversers in cancer cells and bacteria. In this way, the selective antiproliferative activity against multidrug resistant cancer cells of cucurbitacins obtained from M. balsamina, their ability as P-glycoprotein inhibitors in cancer cells overexpressing this ABC transporter, as well as efflux pump inhibitors in resistant bacteria strains are reviewed. Moreover, the in vitro antimalarial activity of cucurbitacins and acyl derivatives against the blood and liver-stages of Plasmodium strains, and the in vivo activity of selected compounds is also reviewed. Besides our work, edible and medicinal uses, and other studies mainly reporting the biological activities of M. balsamina extracts, such as antidiabetic, antibacterial, anti-inflammatory, and antioxidant properties are also addressed.

Influence of altitude on the physicochemical composition and antioxidant capacity of strawberry: a preliminary systematic review and meta-analysis

Abstract: Abstract Several climatic trends are generally associated with altitude, that may influence the nutritional and phytochemical composition of plants. Strawberry is considered a functional food due to biological activities and health benefits. This systematic review and meta-analysis intend to expose possible variations on physicochemical composition and antioxidant capacity of strawberries in regard to altitude. Thirty eligible studies were included for the final meta-analysis. Two altitude ranges were established: 0 – 1000 and 1000—2000 m above sea level. A random-effects model was used to obtain the results. It was discovered that total soluble solids significantly decreased with altitude. Total titratable acidity increased with altitude. Vitamin C and total anthocyanins showed a significant difference between the groups before we discarded some studies. The analysis of altitude for phenolics and antioxidant capacity evaluated for the DPPH radical scavenging method did not identify any significant differences between the studies. The findings suggest that altitude does not affect the physicochemical composition and antioxidant capacity of strawberries; nonetheless, a more exhaustive study is recommended. Graphical abstract