Editorial

5 pages, 203 KiB

Open AccessEditorial

Secondary Metabolites and Their Applications

by Eugenia Gallardo and Ana M. L. Seca

Appl. Sci. 2022, 12(5), 2317; https://doi.org/10.3390/app12052317 - 23 Feb 2022

Cited by 2 | Viewed by 2448

The identification of secondary metabolites present in both terrestrial and marine species continues to be a fundamental and privileged path for the emergence of new and fundamental natural products available on the market with very different applications [...] Full article

(This article belongs to the Special Issue Advances on Applications of Bioactive Natural Compounds)

Research

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16 pages, 3018 KiB

Open AccessArticle

Special Bioactivities of Phenolics from Acacia dealbata L. with Potential for Dementia, Diabetes and Antimicrobial Treatments

by Vanessa Paula, Soraia I. Pedro, Maria G. Campos, Teresa Delgado, Letícia M. Estevinho and Ofélia Anjos

Appl. Sci. 2022, 12(3), 1022; https://doi.org/10.3390/app12031022 - 19 Jan 2022

Cited by 8 | Viewed by 2245

Abstract

Some diseases still need better therapeutic approaches, including the prevention of development. Natural resources are investigated with this purpose; among them, we decided to use an invasive plant as a main strategy. This will help in two ways: screening new compounds in flowers [...] Read more.

Some diseases still need better therapeutic approaches, including the prevention of development. Natural resources are investigated with this purpose; among them, we decided to use an invasive plant as a main strategy. This will help in two ways: screening new compounds in flowers prevents the plant from causing widespread damage by controlling the dissemination and also obtains crude material for further applications. In the present study, flower extracts from Acacia dealbata Link harvested in Portugal were studied during three stages of flowering. Phenolic compounds were evaluated using HPLC/DAD and the total phenolics as the total flavonoids content was determined. The bioactivities screened were antioxidant potential, inhibitory activities of some enzymes (acetylcholinesterase, lipase and α-glucosidase) and, to complete the screening, the inhibition of microbial growth was determined against Gram-negative and Gram-positive bacteria, as well as for yeasts. The data obtained suggested that the hydroethanolic extracts gave good results for all these biological activities and varied according to the maturation status of the flowers, with the early stage being the most active, which can be related to the chalcones content. This new approach will lead to the possible control of the invasive plant and also future perspective research for therapeutic purposes. Full article

(This article belongs to the Special Issue Advances on Applications of Bioactive Natural Compounds)

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16 pages, 1260 KiB

Open AccessFeature PaperArticle

GC- and UHPLC-MS Profiles as a Tool to Valorize the Red Alga Asparagopsis armata

by Diana C. G. A. Pinto, Marie L. Lesenfants, Gonçalo P. Rosa, Maria Carmo Barreto, Artur M. S. Silva and Ana M. L. Seca

Appl. Sci. 2022, 12(2), 892; https://doi.org/10.3390/app12020892 - 16 Jan 2022

Cited by 10 | Viewed by 1950

Abstract

Asparagopsis armata Harvey is a red alga native from the southern hemisphere and then introduced in the Mediterranean Sea and the Atlantic Ocean, including the Azores Archipelago, where it is considered an invasive alga. Some studies show that the extracts exhibit antimicrobial and [...] Read more.

Asparagopsis armata Harvey is a red alga native from the southern hemisphere and then introduced in the Mediterranean Sea and the Atlantic Ocean, including the Azores Archipelago, where it is considered an invasive alga. Some studies show that the extracts exhibit antimicrobial and antifouling activities, and it is incorporated in some commercialized cosmetic products. (e.g., Ysaline^®). However, knowledge of this species chemical composition is scarce. The GC-MS and UHPLC-MS profiles of both the nonpolar and polar extracts were established to contribute to this problem solution. According to the results, A. armata is rich in a great structural variety of halogenated lipophilic and aromatic compounds, some of them identified here for the first time. In the lipophilic extract, 25 compounds are identified, being the halogenated compounds and fatty acids, the two major compound families, corresponding to 54.8% and 35.7% of identified compounds (224 and 147 mg/100 g of dry algae, respectively). The 1,4-dibromobuten-1-ol and the palmitic acid are the two most abundant identified compounds (155 and 83.4 mg/100 g of dry algae, respectively). The polar extract demonstrated the richness of this species in brominated phenolics, from which the cinnamic acid derivatives are predominant. The results obtained herein open new perspectives for valuing the A. armata as a source of halogenated compounds and fatty acids, consequently improving its biotechnological and economic potential. Promoting this seaweed and the consequent increase in its demand will contribute to biodiversity conservation and ecosystem sustainability. Full article

(This article belongs to the Special Issue Advances on Applications of Bioactive Natural Compounds)

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8 pages, 1201 KiB

Open AccessCommunication

Synthesis of Proposed Structure of Aaptoline B via Transition Metal-Catalyzed Cycloisomerization and Evaluation of Its Neuroprotective Properties in C. Elegans

by Soobin Kim, Wooin Yang, Young-Taek Han and Dong-Seok Cha

Appl. Sci. 2021, 11(19), 9125; https://doi.org/10.3390/app11199125 - 30 Sep 2021

Cited by 2 | Viewed by 1301

Abstract

A concise synthesis of the proposed structure of aaptoline B, a pyrroloquinoline derived from a marine sponge, was accomplished. A key feature of this synthesis is the versatile transition metal-catalyzed cycloisomerization of N-propargylaniline to construct a quinoline skeleton. However, the spectral data [...] Read more.

A concise synthesis of the proposed structure of aaptoline B, a pyrroloquinoline derived from a marine sponge, was accomplished. A key feature of this synthesis is the versatile transition metal-catalyzed cycloisomerization of N-propargylaniline to construct a quinoline skeleton. However, the spectral data of the synthesized aaptoline B did not agree with those of previous studies. The structure of the synthesized aaptoline B was confirmed using a combined 2D NMR analysis. Furthermore, we assessed the possible neuroprotective potential of aaptoline B using the C. elegans model system. In this study, aaptoline B significantly improved the viability and the morphology of dopaminergic neurons of nematodes under MPP⁺ exposure conditions. We also found that MPP⁺-induced motor deficits in nematodes were efficiently restored by aaptoline B treatment. Our findings demonstrate the neuroprotective effects of aaptoline B against MPP⁺-induced dopaminergic neuronal damage. Further studies are underway to explain its pharmacological mechanism. Full article

(This article belongs to the Special Issue Advances on Applications of Bioactive Natural Compounds)

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12 pages, 1940 KiB

Open AccessArticle

A Fast Ubiquitination of UHRF1 Oncogene Is a Unique Feature and a Common Mechanism of Thymoquinone in Cancer Cells

by Mahmoud Alhosin, Omeima Abdullah, Asaad Kayali and Ziad Omran

Appl. Sci. 2021, 11(16), 7633; https://doi.org/10.3390/app11167633 - 19 Aug 2021

Cited by 2 | Viewed by 2103

Abstract

Downregulation of the ubiquitin-like containing PHD and ring finger 1 (UHRF1) oncogene in cancer cells in response to natural anticancer drugs, including thymoquinone (TQ), is a key event that induces apoptosis. TQ can induce UHRF1 autoubiquitination via the E3 ligase activity of its [...] Read more.

Downregulation of the ubiquitin-like containing PHD and ring finger 1 (UHRF1) oncogene in cancer cells in response to natural anticancer drugs, including thymoquinone (TQ), is a key event that induces apoptosis. TQ can induce UHRF1 autoubiquitination via the E3 ligase activity of its RING domain, most likely through the downregulation of herpes virus-associated ubiquitin-specific protease (HAUSP). In this study, we evaluated whether HAUSP downregulation and fast ubiquitination of UHRF1 are prerequisites for UHRF1 degradation in response to TQ in cancer cells and whether doxorubicin can mimic the effects of TQ on UHRF1 ubiquitination. RNA sequencing was performed to investigate differentially expressed genes in TQ-treated Jurkat cells. The protein expression of UHRF1, HAUSP and Bcl-2 was detected by means of Western blot analysis. The proliferation of human colon cancer (HCT-116) and Jurkat cells was analyzed via the WST-1 assay. RNA sequencing data revealed that TQ significantly decreased HAUSP expression. TQ triggered UHRF1 to undergo rapid ubiquitination as the first step in its degradation and the inhibition of its cell proliferation. TQ-induced UHRF1 ubiquitination is associated with HAUSP downregulation. Like TQ, doxorubicin induced a similar dose- and time-dependent downregulation of UHRF1 in cancer cells, but UHRF1 did not undergo ubiquitination as detected in response to TQ. Furthermore, TQ decreased Bcl-2 expression without triggering its ubiquitination. A fast UHRF1 ubiquitination is an indispensable event for its degradation in response to TQ but not for its responses to doxorubicin. TQ appears to trigger ubiquitination of UHRF1 but not of the Bcl-2 oncogene, thereby identifying UHRF1 as a specific target of TQ for cancer therapy. Full article

(This article belongs to the Special Issue Advances on Applications of Bioactive Natural Compounds)

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16 pages, 3603 KiB

Open AccessFeature PaperArticle

Extraction of Antioxidant Compounds and Pigments from Spirulina (Arthrospira platensis) Assisted by Pulsed Electric Fields and the Binary Mixture of Organic Solvents and Water

by Francisco J. Martí-Quijal, Francesc Ramon-Mascarell, Noelia Pallarés, Emilia Ferrer, Houda Berrada, Yuthana Phimolsiripol and Francisco J. Barba

Appl. Sci. 2021, 11(16), 7629; https://doi.org/10.3390/app11167629 - 19 Aug 2021

Cited by 39 | Viewed by 4058

Abstract

The application of pulsed electric fields (PEF) is an innovative extraction technology promoting cell membrane electroporation, thus allowing for an efficient recovery, from an energy point of view, of antioxidant compounds (chlorophylls, carotenoids, total phenolic compounds, etc.) from microalgae. Due to its selectivity [...] Read more.

The application of pulsed electric fields (PEF) is an innovative extraction technology promoting cell membrane electroporation, thus allowing for an efficient recovery, from an energy point of view, of antioxidant compounds (chlorophylls, carotenoids, total phenolic compounds, etc.) from microalgae. Due to its selectivity and high extraction yield, the effects of PEF pre-treatment (3 kV/cm, 100 kJ/kg) combined with supplementary extraction at different times (5–180 min) and with different solvents (ethanol (EtOH)/H₂O, 50:50, v/v; dimethyl sulfoxide (DMSO)/H₂O, 50:50, v/v) were evaluated in order to obtain the optimal conditions for the extraction of different antioxidant compounds and pigments. In addition, the results obtained were compared with those of a conventional treatment (without PEF pre-treatment but with constant shaking). After carrying out the different experiments, the best extraction conditions to recover the different compounds were obtained after applying PEF pre-treatment combined with the binary mixture EtOH/H₂O, 50:50, v/v, for 60–120 min. PEF extraction was more efficient throughout the study, especially at short extraction times (5–15 min). In this sense, recovery of 55–60%, 85–90%, and 60–70% was obtained for chlorophylls, carotenoids, and total phenolic compounds, respectively, compared to the maximum total extracted amount. These results show that PEF improves the extraction yield of antioxidant bioactive compounds from microalgae and is a promising technology due to its profitability and environmental sustainability. Full article

(This article belongs to the Special Issue Advances on Applications of Bioactive Natural Compounds)

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13 pages, 2487 KiB

Open AccessArticle

Isolation and Identification of Two Potent Phytotoxic Substances from Afzelia xylocarpa for Controlling Weeds

by Ramida Krumsri, Kaori Ozaki, Toshiaki Teruya and Hisashi Kato-Noguchi

Appl. Sci. 2021, 11(8), 3542; https://doi.org/10.3390/app11083542 - 15 Apr 2021

Cited by 3 | Viewed by 2020

Abstract

Phytotoxic substances released from plants are considered eco-friendly alternatives for controlling weeds in agricultural production. In this study, the leaves of Afzelia xylocarpa (Kurz) Craib. were investigated for biological activity, and their active substances were determined. Extracts of A. xylocarpa leaf exhibited concentration-dependent [...] Read more.

Phytotoxic substances released from plants are considered eco-friendly alternatives for controlling weeds in agricultural production. In this study, the leaves of Afzelia xylocarpa (Kurz) Craib. were investigated for biological activity, and their active substances were determined. Extracts of A. xylocarpa leaf exhibited concentration-dependent phytotoxic activity against the seedling length of Lepidium sativum L., Medicago sativa L., Phleum pratense L., and Echinochloa crus-galli (L.) P. Beauv. Bioassay-guided fractionation of the A. xylocarpa leaf extracts led to isolating and identifying two compounds: vanillic acid and trans-ferulic acid. Both compounds were applied to four model plants using different concentrations. The results showed both compounds significantly inhibited the model plants’ seedling length in a species-dependent manner (p < 0.05). The phytotoxic effects of trans-ferulic acid (IC₅₀ = 0.42 to 2.43 mM) on the model plants were much greater than that of vanillic acid (IC₅₀ = 0.73 to 3.17 mM) and P. pratense was the most sensitive to both compounds. In addition, the application of an equimolar (0.3 mM) mixture of vanillic acid and trans-ferulic acid showed the synergistic effects of the phytotoxic activity against the root length of P. pratense and L. sativum. These results suggest that the leaves of A. xylocarpa and its phytotoxic compounds could be used as a natural source of herbicides. Full article

(This article belongs to the Special Issue Advances on Applications of Bioactive Natural Compounds)

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10 pages, 1717 KiB

Open AccessArticle

Identification and Application of Bioactive Compounds from Garcinia xanthochymus Hook. for Weed Management

by Md. Mahfuzur Rob, Kawsar Hossen, Mst. Rokeya Khatun, Keitaro Iwasaki, Arihiro Iwasaki, Kiyotake Suenaga and Hisashi Kato-Noguchi

Appl. Sci. 2021, 11(5), 2264; https://doi.org/10.3390/app11052264 - 04 Mar 2021

Cited by 15 | Viewed by 2773

Abstract

The allelopathic potential of plant species and their related compounds has been increasingly reported to be biological tools for weed control. The allelopathic potential of Garcinia xanthochymus was assessed against several test plant species: lettuce, rapeseed, Italian ryegrass, and timothy. The extracts of [...] Read more.

The allelopathic potential of plant species and their related compounds has been increasingly reported to be biological tools for weed control. The allelopathic potential of Garcinia xanthochymus was assessed against several test plant species: lettuce, rapeseed, Italian ryegrass, and timothy. The extracts of G. xanthochymus leaves significantly inhibited all the test plants in a concentration- and species-specific manner. Therefore, to identify the specific compounds involved in the allelopathic activity of the G. xanthochymus extracts, assay-guided purification was carried out and two allelopathic compounds were isolated and identified as methyl phloretate {3-(4-hydroxyphenyl) propionic acid methyl ester} and vanillic acid (4-hydroxy-3-methoxybenzoic acid). Both of the substances significantly arrested the cress and timothy seedlings growth. I₅₀ values (concentrations required for 50% inhibition) for shoots and roots growth of the cress and timothy were 113.6–104.6 and 53.3–40.5 μM, respectively, for methyl phloretate, and 331.6–314.7 and 118.8–107.4 μM, respectively, for vanillic acid, which implied that methyl phloretate was close to 3- and 2-fold more effective than vanillic acid against cress and timothy, respectively. This report is the first on the presence of methyl phloretate in a plant and its phytotoxic property. These observations suggest that methyl phloretate and vanillic acid might participate in the phytotoxicity of G. xanthochymus extract. Full article

(This article belongs to the Special Issue Advances on Applications of Bioactive Natural Compounds)

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Review

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23 pages, 2562 KiB

Open AccessReview

Comparison of the Biological Potential and Chemical Composition of Brazilian and Mexican Propolis

by Norma Patricia Silva-Beltrán, Marcelo Andrés Umsza-Guez, Daniela Méria Ramos Rodrigues, Juan Carlos Gálvez-Ruiz, Thiago Luiz de Paula Castro and Ana Paola Balderrama-Carmona

Appl. Sci. 2021, 11(23), 11417; https://doi.org/10.3390/app112311417 - 02 Dec 2021

Cited by 16 | Viewed by 3355

Abstract

Propolis is a resinous substance collected by bees from plants and its natural product is available as a safe therapeutic option easily administered orally and readily available as a natural supplement and functional food. In this work, we review the most recent scientific [...] Read more.

Propolis is a resinous substance collected by bees from plants and its natural product is available as a safe therapeutic option easily administered orally and readily available as a natural supplement and functional food. In this work, we review the most recent scientific evidence involving propolis from two countries (Brazil and Mexico) located in different hemispheres and with varied biomes. Brazil has a scientifically well documented classification of different types of propolis. Although propolis from Brazil and Mexico present varied compositions, they share compounds with recognized biological activities in different extraction processes. Gram-negative bacteria growth is inhibited with lower concentrations of different types of propolis extracts, regardless of origin. Prominent biological activities against cancer cells and fungi were verified in the different types of extracts evaluated. Antiprotozoal activity needs to be further evaluated for propolis of both origins. Regarding the contamination of propolis (e.g., pesticides, toxic metals), few studies have been carried out. However, there is evidence of chemical contamination in propolis by anthropological action. Studies demonstrate the versatility of using propolis in its different forms (extracts, products, etc.), but several potential applications that might improve the value of Brazilian and Mexican propolis should still be investigated. Full article

(This article belongs to the Special Issue Advances on Applications of Bioactive Natural Compounds)

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19 pages, 2153 KiB

Open AccessFeature PaperReview

Insights into the Bioactivities and Chemical Analysis of Ailanthus altissima (Mill.) Swingle

by Débora Caramelo, Soraia I. Pedro, Hernâni Marques, Ana Y. Simão, Tiago Rosado, Celina Barroca, Jorge Gominho, Ofélia Anjos and Eugenia Gallardo

Appl. Sci. 2021, 11(23), 11331; https://doi.org/10.3390/app112311331 - 30 Nov 2021

Cited by 9 | Viewed by 3671

Abstract

Many species of the so-called exotic plants coexist with native species in a balanced way, but others thrive very quickly and escape human control, becoming harmful—these are called invasive alien species. In addition to overcoming geographic barriers, these species can defeat biotic and [...] Read more.

Many species of the so-called exotic plants coexist with native species in a balanced way, but others thrive very quickly and escape human control, becoming harmful—these are called invasive alien species. In addition to overcoming geographic barriers, these species can defeat biotic and abiotic barriers, maintaining stable populations. Ailanthus altissima is no exception; it is disseminated worldwide and is considered high risk due to its easy propagation and resistance to external environmental factors. Currently, it has no particular use other than ornamental, even though it is used to treat epilepsy, diarrhea, asthma, ophthalmic diseases, and seborrhoea in Chinese medicine. Considering its rich composition in alkaloids, terpenoids, sterols, and flavonoids, doubtlessly, its use in medicine or other fields can be maximised. This review will focus on the knowledge of the chemical composition and the discovery of the biological properties of A. altissima to understand this plant better and maximise its possible use for purposes such as medicine, pharmacy, or the food industry. Methods for the extraction and detection to know the chemical composition will also be discussed in detail. Full article

(This article belongs to the Special Issue Advances on Applications of Bioactive Natural Compounds)

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25 pages, 4450 KiB

Open AccessReview

Bioactive Compounds and Nanodelivery Perspectives for Treatment of Cardiovascular Diseases

by Rakesh K. Sindhu, Annima Goyal, Evren Algın Yapar and Simona Cavalu

Appl. Sci. 2021, 11(22), 11031; https://doi.org/10.3390/app112211031 - 21 Nov 2021

Cited by 13 | Viewed by 4064

Abstract

Bioactive compounds are comprised of small quantities of extra nutritional constituents providing both health benefits and enhanced nutritional value, based on their ability to modulate one or more metabolic processes. Plant-based diets are being thoroughly researched for their cardiovascular properties and effectiveness against [...] Read more.

Bioactive compounds are comprised of small quantities of extra nutritional constituents providing both health benefits and enhanced nutritional value, based on their ability to modulate one or more metabolic processes. Plant-based diets are being thoroughly researched for their cardiovascular properties and effectiveness against cancer. Flavonoids, phytoestrogens, phenolic compounds, and carotenoids are some of the bioactive compounds that aim to work in prevention and treating the cardiovascular disease in a systemic manner, including hypertension, atherosclerosis, and heart failure. Their antioxidant and anti-inflammatory properties are the most important characteristics that make them favorable candidates for CVDs treatment. However, their low water solubility and stability results in low bioavailability, limited accessibility, and poor absorption. The oral delivery of bioactive compounds is constrained due to physiological barriers such as the pH, mucus layer, gastrointestinal enzymes, epithelium, etc. The present review aims to revise the main bioactive compounds with a significant role in CVDs in terms of preventive, diagnostic, and treatment measures. The advantages of nanoformulations and novel multifunctional nanomaterials development are described in order to overcome multiple obstacles, including the physiological ones, by summarizing the most recent preclinical data and clinical trials reported in the literature. Nanotechnologies will open a new window in the area of CVDs with the opportunity to achieve effective treatment, better prognosis, and less adverse effects on non-target tissues. Full article

(This article belongs to the Special Issue Advances on Applications of Bioactive Natural Compounds)

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21 pages, 2645 KiB

Open AccessReview

Recent Advances in the Heterologous Biosynthesis of Natural Products from Streptomyces

by Van Thuy Thi Pham, Chung Thanh Nguyen, Dipesh Dhakal, Hue Thi Nguyen, Tae-Su Kim and Jae Kyung Sohng

Appl. Sci. 2021, 11(4), 1851; https://doi.org/10.3390/app11041851 - 19 Feb 2021

Cited by 9 | Viewed by 3917

Abstract

Streptomyces is a significant source of natural products that are used as therapeutic antibiotics, anticancer and antitumor agents, pesticides, and dyes. Recently, with the advances in metabolite analysis, many new secondary metabolites have been characterized. Moreover, genome mining approaches demonstrate that many silent [...] Read more.

Streptomyces is a significant source of natural products that are used as therapeutic antibiotics, anticancer and antitumor agents, pesticides, and dyes. Recently, with the advances in metabolite analysis, many new secondary metabolites have been characterized. Moreover, genome mining approaches demonstrate that many silent and cryptic biosynthetic gene clusters (BGCs) and many secondary metabolites are produced in very low amounts under laboratory conditions. One strain many compounds (OSMAC), overexpression/deletion of regulatory genes, ribosome engineering, and promoter replacement have been utilized to activate or enhance the production titer of target compounds. Hence, the heterologous expression of BGCs by transferring to a suitable production platform has been successfully employed for the detection, characterization, and yield quantity production of many secondary metabolites. In this review, we introduce the systematic approach for the heterologous production of secondary metabolites from Streptomyces in Streptomyces and other hosts, the genome analysis tools, the host selection, and the development of genetic control elements for heterologous expression and the production of secondary metabolites. Full article

(This article belongs to the Special Issue Advances on Applications of Bioactive Natural Compounds)

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