Antioxidant, Antihypertensive and Antimicrobial Properties of Phenolic Compounds Obtained from Native Plants by Different Extraction Methods

Seriphidium herba-alba (Asso): A comprehensive study of essential oils, extracts, and their antimicrobial properties

Seriphidium herba-alba (Asso), a plant celebrated for its therapeutic qualities, is widely used in traditional medicinal practices throughout the Middle East and North Africa. In a detailed study of Seriphidium herba-alba (Asso), essential oils and extracts were analyzed for their chemical composition and antimicrobial properties. The essential oil, characterized using mass spectrometry and retention index methods, revealed a complex blend of 52 compounds, with santolina alcohol, α-thujone, β-thujone, and chrysanthenone as major constituents. Extraction yields varied significantly, depending on the plant part and method used; notably, methanol soaking of aerial parts yielded the most extract at 17.75%. The antimicrobial analysis showed that the extracts had selective antibacterial activity, particularly against Staphylococcus aureus, and broad-spectrum antifungal activity against organisms such as Candida albicans and Aspergillus spp. The methanol-soaked extract demonstrated the strongest antimicrobial properties, indicating its potential as a natural antimicrobial source. This study not only underscores the therapeutic potential of Seriphidium herba-alba (Asso) in pharmaceutical applications but also sets a foundation for future research focused on isolating specific bioactive compounds and in vivo testing.

Phytochemical profiles and evaluation of the biological potential of ethyl acetate and n-butanol fractions of the aerial parts of Cistus albidus L

The phytochemical profiles of the ethyl acetate (EAFCA) and n-butanol (BFCA) fractions of the aerial parts of Cistus albidus L., were characterised by a developed LC-ESI-MS/MS method, using 53 fingerprint phytochemicals, revealing the presence of 26 and 22 compounds, respectively with quinic acid, gallic acid, protocatechuic acid, catechin, gentisic acid, tannic acid, ellagic acid, quercitrin, astragalin as the major compounds of the EAFCA, in very higher amounts than in the BFCA. The antioxidant activity was evaluated using six methods (DPPH•, ABTS•+, GOR•, CUPRAC, FRAP and Phenanthroline). In agreement with its highest polyphenolic content (430.12 ± 1.02 µg GAE/mg of extract) and largest amounts of identified polyphenolics, the EAFCA exhibited a higher antioxidant activity than the BFCA. Additionally, the EAFCA showed the highest acetylcholinesterase (AChE) inhibition (IC50 of 25.1 ± 2.58 µg/mL). Moreover, both EAFCA and BFCA demonstrated high photoprotective activity, with sun protection factor (SPF) values of 36.49 and 36.52, respectively.

Characterization of the Chemical Composition and Biological Activities of Bog Bilberry (Vaccinium uliginosum L.) Leaf Extracts Obtained via Various Extraction Techniques

This investigation aimed to assess the chemical composition and biological activities of bog bilberry (Vaccinium uliginosum L.) leaves. Hydroethanolic extracts were obtained using four extraction techniques: one conventional (CE) and three alternative methods; ultrasound (UAE), microwave (MAE) and high-pressure (HPE) extractions. Spectrophotometric analysis was conducted to determine their chemical content, including the total phenolic content (TPC) and total flavonoid content (TFC). Furthermore, their antioxidative and antimicrobial properties were evaluated. HPLC (high performance liquid chromatography) analysis identified and quantified 17 phenolic compounds, with chlorogenic acid being the predominant compound, with the lowest level (37.36 ± 0.06 mg/g) for the bog bilberry leaf extract obtained by CE and the highest levels (e.g., HPE = 44.47 ± 0.08 mg/g) for the bog bilberry leaf extracts obtained by the alternative methods. Extracts obtained by HPE, UAE and MAE presented TPC values (135.75 ± 2.86 mg GAE/g; 130.52 ± 1.99 mg GAE/g; 119.23 ± 1.79 mg GAE/g) higher than those obtained by the CE method (113.07 ± 0.98 mg GAE/g). Regarding the TFC values, similar to TPC, the highest levels were registered in the extracts obtained by alternative methods (HPE = 43.16 ± 0.12 mg QE/g; MAE = 39.79 ± 0.41 mg QE/g and UAE = 33.89 ± 0.35 mg QE/g), while the CE extract registered the lowest level, 31.47 ± 0.28 mg QE/g. In the case of DPPH (1,1-diphenyl-2-picrylhydrazyl) antioxidant activity, the extracts from HPE, UAE and MAE exhibited the strongest radical scavenging capacities of 71.14%, 63.13% and 60.84%, respectively, whereas the CE extract registered only 55.37%. According to Microbiology Reader LogPhase 600 (BioTek), a common MIC value of 8.88 mg/mL was registered for all types of extracts against Staphylococcus aureus (Gram-positive bacteria) and Salmonella enterica (Gram-negative bacteria). Moreover, the alternative extraction methods (UAE, HPE) effectively inhibited the growth of Candida parapsilosis, in comparison to the lack of inhibition from the CE method. This study provides valuable insights into bog bilberry leaf extracts, reporting a comprehensive evaluation of their chemical composition and associated biological activities, with alternative extraction methods presenting greater potential for the recovery of phenolic compounds with increased biological activities than the conventional method.

Evaluation of Olive Leaf Phenolic Compounds' Gastrointestinal Stability Based on Co-Administration and Microencapsulation with Non-Digestible Carbohydrates

The large generation of olive by-products has motivated their revalorization into high-added-value products. In this regard, olive leaves pose as an interesting source of bioactive compounds, due to their phenolic content with commonly known antioxidant, anti-inflammatory, and immunomodulatory properties, with potential application in non-communicable diseases. However, their effectiveness and applicability into functional foods is limited by their instability under gastrointestinal conditions. Thus, the development of protective formulations is essential. In this study, the spray-drying encapsulation of a phenolic-rich olive leaf extract with inulin as the encapsulating agent was optimized. Then, the behavior of the free extract under gastrointestinal conditions, its co-administration with the encapsulating agent, and the optimized microencapsulated formulation were studied through an in vitro gastrointestinal digestion process following the INFOGEST protocol. Digestion of the free extract resulted in the degradation of most compounds, whereas this was minimized in the co-administration of the non-encapsulated extract with the encapsulating agent. This protective effect, related to its interaction with inulin, was similar to the microencapsulated formulation. Thus, both approaches, co-administration and microencapsulation with inulin, could be promising strategies for the improvement of the stability of these anti-inflammatory and immunomodulatory compounds under gastrointestinal conditions, enhancing their beneficial effect.

Antifungal Effect of Autochthonous Aromatic Plant Extracts on Two Mycotoxigenic Strains of Aspergillus flavus

This study identified the compounds obtained from four native Dehesa plants, which were holm oak, elm, blackberry and white rockrose, and evaluated their ability to inhibit the growth and production of aflatoxins B₁ and B₂ of two strains of mycotoxigenic Aspergillus flavus. For this purpose, phenolic compounds present in the leaves and flowers of the plants were extracted and identified, and subsequently, the effect on the growth of A. flavus, aflatoxin production and the expression of a gene related to its synthesis were studied. Cistus albidus was the plant with the highest concentration of phenolic compounds, followed by Quercus ilex. Phenolic acids and flavonoids were mainly identified, and there was great variability among plant extracts in terms of the type and quantity of compounds. Concentrated and diluted extracts were used for each individual plant. The influence on mold growth was not very significant for any of the extracts. However, those obtained from plants of the genus Quercus ilex, followed by Ulmus sp., were very useful for inhibiting the production of aflatoxin B₁ and B₂ produced by the two strains of A. flavus. Expression studies of the gene involved in the aflatoxin synthesis pathway did not prove to be effective. The results indicated that using these new natural antifungal compounds from the Dehesa for aflatoxin production inhibition would be desirable, promoting respect for the environment by avoiding the use of chemical fungicides. However, further studies are needed to determine whether the specific phenolic compounds responsible for the antifungal activity of Quercus ilex and Ulmus sp. produce the antifungal activity in pure form, as well as to verify the action mechanism of these compounds.

Antimicrobial Properties of Essential Oils Obtained from Autochthonous Aromatic Plants

The aim of this work was to determine the antimicrobial activity of the essential oils of six plants widely distributed in the Dehesa of Extremadura, such as Calendula officinalis, Cistus ladanifer, Cistus salviifolius, Cistus multiflorus, Lavandula stoechas, and Rosmarinus officinalis. The content of total phenolic compounds (TPC) and the antimicrobial activity of the essential oils against pathogenic and spoilage bacteria and yeasts as well as aflatoxin-producing molds were determined. A great variability was observed in the composition of the essential oils obtained from the six aromatic plants. The Cistus ladanifer essential oil had the highest content of total phenols (287.32 ppm), followed by the Cistus salviifolius essential oil; and the Rosmarinus officinalis essential oil showed the lowest amount of these compounds. The essential oils showed inhibitory effects on the tested bacteria and also yeasts, showing a maximum inhibition diameter of 11.50 mm for Salmonella choleraesuis and Kregervanrija fluxuum in the case of Cistus ladanifer and a maximum diameter of 9 mm for Bacillus cereus and 9.50 mm for Priceomyces carsonii in the case of Cistus salviifolius. The results stated that antibacterial and antiyeast activity is influenced by the concentration and the plant material used for essential oil preparation. In molds, aflatoxin production was inhibited by all the essential oils, especially the essential oils of Cistus ladanifer and Cistus salviifolius. Therefore, it can be concluded that the essential oils of native plants have significant antimicrobial properties against pathogenic and spoilage microorganisms, so they could be studied for their use in the industry as they are cheap, available, and non-toxic plants that favor the sustainability of the environment of the Dehesa of Extremeña.

Effects of Riceberry Rice Bran Oil Supplementation on Oxidative Stress and Cardiovascular Risk Biomarkers in Older Adults with Prehypertension

We investigated the changes in the oxidative stress and cardiovascular disease risk biomarkers, including the activity of the cardiac autonomic nervous system, in older adults with prehypertension following Riceberry rice bran oil supplementation. A total of 35 women aged 60 to 76 years with prehypertension were randomly allocated to two groups, one of which was supplemented with rice bran oil (n=18) and the other with Riceberry rice bran oil (n=17) at 1,000 mg daily for 8 weeks. Prior to and after the supplementation, oxidative stress and cardiovascular risk biomarkers (primary outcomes), heart rate variability, and blood pressure (secondary outcomes) were investigated. Results showed that plasma malondialdehyde, blood glutathione disulfide, and tumor necrosis factor-alpha levels were significantly decreased, and the ratio of reduced glutathione to glutathione disulfide significantly increased in both groups after supplementation (all P<0.05). No significant differences were observed between groups. Heart rate variability and blood pressure did not statistically significantly change subsequent to supplementation in either group and did not differ between groups. In conclusion, Riceberry rice bran oil supplementation for 8 weeks alleviates oxidative stress and inflammation in older adults with prehypertension to a similar extent as rice bran oil supplementation.

Essential Oils and Melatonin as Functional Ingredients in Dogs

Simple Summary

Phytogenics are plant-based compounds with beneficial actions in feed technology and/or animal health. These so-called plant secondary metabolites are very diverse and with wide possible applications in humans and animals. Among them, essential oils (EOs) are the most used in feed for livestock and pets. Lately, melatonin has acquired new and interesting applications in dogs. Recent studies using EOs and/or melatonin in dog feeding and their involvement in health aspects are presented.

Abstract

The use of nutraceuticals or functional ingredients is increasingly widespread in human food; their use is also widespread in animal feed. These natural compounds generally come from plant materials and comprise a wide range of substances of a very diverse chemical nature. In animals, these compounds, so-called phytogenics, are used to obtain improvements in feed production/stability and also as functional components with repercussions on animal health. Along with polyphenols, isoprenoid compounds represent a family of substances with wide applications in therapy and pet nutrition. Essential oils (EOs) are a group of complex substances with fat-soluble nature that are widely used. Melatonin is an indolic amine present in all living with amphiphilic nature. In this work, we present a review of the most relevant phytogenics (polyphenol, isoprenoid, and alkaloid compounds), their characteristics, and possible uses as nutraceuticals in dogs, with special emphasis on EOs and their regulatory aspects, applied in foods and topically. Additionally, a presentation of the importance of the use of melatonin in dogs is developed, giving physiological and practical aspects about its use in dog feeding and also in topical application, with examples and future projections. This review points to the combination of EOs and melatonin in food supplements and in the topical application as an innovative product and shows excellent perspectives aimed at addressing dysfunctions in pets, such as the treatment of stress and anxiety, sleep disorders, alopecia, and hair growth problems, among others.

Labdanum Resin from Cistus ladanifer L.: A Natural and Sustainable Ingredient for Skin Care Cosmetics with Relevant Cosmeceutical Bioactivities

Labdanum resin from Cistus ladanifer L. (Cistaceae) is an abundant natural resource in the Iberian Peninsula worth being explored in a sustainable manner. It is already used in the cosmetic industry; mainly by the fragrances/perfumery sector. However, given the highest market share and traditional uses, labdanum resin also has the potential to be used and valued as a cosmetic ingredient for skincare. Aiming to evaluate this potential, labdanum methanolic absolute and fractions purified by column chromatography were characterized by UPLC-DAD-ESI-MS and then evaluated for UV-protection, antioxidant, anti-elastase, anti-inflammatory, and antimicrobial activities. Labdanum absolute represented ~70% of the resin; diterpenoid and flavonoid fractions represented ~75% and 15% of the absolute, respectively. Labdane-type diterpenoids and methylated flavonoids were the main compounds in labdanum absolute and in diterpenoid and flavonoid fractions, respectively. Labdanum absolute showed a spectrophotometric sun protection factor (SPF) near 5, which is mainly due to flavonoids, as the flavonoids’ SPF was 13. Low antioxidant activity was observed, with ABTS radical scavenging being the most significant (0.142 ± 0.017, 0.379 ± 0.039 and 0.010 ± 0.003 mgTE/mgExt, for the absolute and flavonoid and terpene fractions, respectively). Anti-aging and anti-inflammatory activity are reported here for the first time, by the inhibition of elastase activity (22% and 13%, by absolute and flavonoid extract at 1 mg/mL), and by the inhibition of nitric oxide production in LPS-induced RAW 264.7 cells (84% to 98%, at 15 µg/mL extracts, flavonoid fraction the most active), respectively. Antimicrobial activity, against relevant skin and cosmetic product microorganisms, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, and Escherichia coli, revealed that only S. aureus was susceptible to labdanum absolute (MIC: 1.2 mg/mL) and its fractions (MIC: <0.3 mg/mL). In conclusion, labdanum resin showed potential to be used in sunscreen cosmetics, anti-inflammatory skincare cosmeceuticals or medicines but has low potential as a cosmetic product preservative given the low antioxidant and low-spectrum antimicrobial activities.