Nowadays, there is an interest in the consumption of food without synthetic additives and rather with the use of natural preservatives. In this regard, natural extracts of the Lamiaceae family, such as rosemary, have been studied because of its bioactive properties. Several studies have reported that rosemary extracts show biological bioactivities such as hepatoprotective, antifungal, insecticide, antioxidant and antibacterial. It is well known that the biological properties in rosemary are mainly due to phenolic compounds. However, it is essential to take into account that these biological properties depend on different aspects. Their use in foods is limited because of their odour, colour and taste. For that reason, commercial methods have been developed for the preparation of odourless and colourless antioxidant compounds from rosemary. Owing to the new applications of natural extracts in preservatives, this review gives a view on the use of natural extract from rosemary in foods and its effect on preservative activities. Specifically, the relationship between the structure and activity (antimicrobial and antioxidant) of the active components in rosemary are being reviewed.

Natural extracts (rich in bioactive compounds) that can be obtained from the leaves, peels and seeds, such as the studied extracts of Pomegranate (P), Rosemary (RA, Nutrox OS (NOS) and Nutrox OVS (NOVS)), and olive (Olea europaea) extracts rich in hydroxytyrosol (HYT-F from olive fruit and HYT-L from olive leaf) can act as antioxidant and antimicrobial agents in food products to replace synthetic additives. The total phenolic compounds, antioxidant capacity (measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-Azinobis (3-ethylbenzothiazolin) -6-sulphonic acid (ABTS), Ferric Reducing Antioxidant Power (FRAP), and Oxygen Radical Absorbance Capacity (ORAC_H)) and their antimicrobial power (using the diffusion disk method with the Escherichia Coli, Lysteria monocytogenes, and Staphilococcus Aureus strains) were measured. The results showed that all the extracts were good antioxidant and antimicrobial compounds in vitro. On the other hand, their antioxidant and antimicrobial capacity was also measured in fish products acting as preservative agents. For that, volatile fatty acid compounds were analysed by GS-MS at day 0 and 11 from elaboration, together with total vial count (TVC), total coliform count (TCC), E. Coli, and L. monocytogenes content at day 0, 4, 7 and 11 under refrigerated storage. The fish patties suffered rapid lipid oxidation and odour and flavour spoilage associated with slight rancidity. Natural extracts from pomegranate, rosemary, and hydroxytyrosol delayed the lipid oxidation, measured as volatile compounds, and the microbiological spoilage in fish patties. Addition of natural extracts to fish products contributed to extend the shelf life of fish under retail display conditions.

Ultraviolet (UV) radiation, especially types A (UVA) and B (UVB), is one of the main causes of skin disorders, including photoaging and skin cancer. Ultraviolent radiation causes oxidative stress, inflammation, p53 induction, DNA damage, mutagenesis, and oxidation of various molecules such as lipids and proteins. In recent decades, the use of polyphenols as molecules with an antioxidant and anti-inflammatory capacity has increased. However, some of these compounds are poorly soluble, and information regarding their absorption and bioavailability is scarce. The main objective of this study was to compare the intestinal absorption and biological activity of apigenin and its more soluble potassium salt (apigenin-K) in terms of antioxidant and photoprotective capacity. Photoprotective effects against UVA and UVB radiation were studied in human keratinocytes, and antioxidant capacity was determined by different methods, including trolox equivalent antioxidant capacity (TEAC), ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) assays. Finally, the intestinal absorption of both apigenins was determined using an in vitro Caco-2 cell model. Apigenin showed a slightly higher antioxidant capacity in antioxidant activity assays when compared with apigenin-K. However, no significant differences were obtained for their photoprotective capacities against UVA or UVB. Results indicated that both apigenins protected cell viability in approximately 50% at 5 J/m² of UVA and 90% at 500 J/m² of UVB radiation. Regarding intestinal absorption, both apigenins showed similar apparent permeabilities (P_app), 1.81 × 10⁻⁵ cm/s and 1.78 × 10⁻⁵ cm/s, respectively. Taken together, these results suggest that both apigenins may be interesting candidates for the development of oral (nutraceutical) and topical photoprotective ingredients against UVA and UVB-induced skin damage, but the increased water solubility of apigenin-K makes it the best candidate for further development.

Natural extracts obtained from fruit and vegetable processing are important sources of phenolic compounds and nitrates, with excellent antioxidant and antimicrobial properties. The aim of this study was to characterize and determine the antioxidant and antimicrobial capacity of several natural extracts (citric (Ct), acerola (Ac), rosemary (R), paprika, garlic, oregano, beet (B), lettuce (L), arugula (A), spinach (S), chard (Ch), celery (Ce), and watercress (W)), both in vitro and applied to a cured meat product (chorizo). For that, the volatile compounds by GC-MS and microbial growth were determined. The total phenolic and nitrate contents were measured and related with their antioxidant capacity (measured by DPPH, ABTS, FRAP, and ORAC methods) and antimicrobial capacity against Clostridium perfringens growth in vitro. In order to study the antioxidant and antimicrobial activities of the extracts in food, their properties were also measured in Spanish chorizo enriched with these natural extracts. R and Ct showed the highest antioxidant capacity, however, natural nitrate sources (B, L, A, S, Ch, Ce, and W) also presented excellent antimicrobial activity against C. perfringens. The incorporation of these extracts as preservatives in Spanish chorizo also presented excellent antioxidant and antimicrobial capacities and could be an excellent strategy in order to produce clean label dry-cured meat products.

Background: we have evaluated the antihypertensive effect of several flavonoid extracts in a rat model of arterial hypertension caused by chronic administration (6 weeks) of the nitric oxide synthesis inhibitor, L-NAME. Methods: Sprague Dawley rats received L-NAME alone or L-NAME plus flavonoid-rich vegetal extracts (Lemon, Grapefruit + Bitter Orange, and Cocoa) or purified flavonoids (Apigenin and Diosmin) for 6 weeks. Results: L-NAME treatment resulted in a marked elevation of blood pressure, and treatment with Apigenin, Lemon Extract, and Grapefruit + Bitter Orange extracts significantly reduced the elevated blood pressure of these animals. Apigenin and some of these flavonoids also ameliorated nitric oxide-dependent and -independent aortic vasodilation and elevated nitrite urinary excretion. End-organ abnormalities such as cardiac infarcts, hyaline arteriopathy and fibrinoid necrosis in coronary arteries and aorta were improved by these treatments, reducing the end-organ vascular damage. Conclusions: the flavonoids included in this study, specially apigenin, may be used as functional food ingredients with potential therapeutic benefit in arterial hypertension.