Synergistic effects of essential oils and phenolic extracts on antimicrobial activities using blends of Artemisia campestris, Artemisia herba alba, and Citrus aurantium.

This study explores the synergistic antibacterial effects of essential oils (EOs) and phenolic extracts from three plants against foodborne pathogenic bacteria. The present work aimed to investigate the synergistic effects of the binary and the ternary combinations of extracts using different blend proportions of the following plant extracts: Artemisia campestris (AC), Artemisia herba alba (AHA), and Citrus aurantium (CA). The antimicrobial activities of EOs and phenolic extracts were determined and evaluated against five strains. For the EOs, the results of the DIZ showed the existence of synergism for different combinations of binary blends, such as AC/AHA or AHA/CA against Escherichia coli, and AC/CA against Enterobacter faecalis. In addition, ternary blends of AC:AHA:CA at a ratio of 1/6:2/3:1/6 exhibited a synergy effect, as measured by the CI, against E. coli. On the other hand, for the phenolic extracts, synergistic effects were noticed for binary blends of AC/CA at different ratios against E. coli, E. faecalis, and Pseudomonas aeruginosa strains. Similarly, ternary blends of phenolic extracts presented synergy against E. coli, E. faecalis, P. aeruginosa strains, and even C. albicans. In this case, the blending ratios were crucial determining factors for maximizing the synergy effect. The study established that the proportion of a single drug could play an essential role in determining the bioefficacy of a drug combination treatment. Therefore, the results showed the importance of studying the modulation of antibacterial activities based on the proportions of extracts in the mixture and finding the range of proportions (as determined by SLMD) that have a synergistic/additive/antagonistic effect with no or low side effects, which can be used in a food preservation system.

The chemical profile and seasonal variation of the composition of the phenolic acids in different plant parts of Centaurea sp.

This study investigated the seasonal variation (over seven months) of phenolic acid (PHA) components in different parts of Centaurea sp. The primary objective was to determine the pattern of variation, while the secondary objective was to identify which month or growth stage provides a greater total PHA content or percentage of bioactive components. Different patterns of seasonal variations were highlighted for the different PHA components and their classes (hydroxybenzoic and -cinnamic acids) in different parts of the plant. The leaves exclusively provided the highest PHA contents, with maximum values reached in April (1368.06 µg/g). The major hydroxybenzoic acid derivatives (HBAs) identified in the leaves were vanillic acid (VaA) "154.18-374.06 µg/g" and protocatechuic acid (PA) "9.37-595.61 µg/g", while the major hydroxycinnamic acid derivatives (HCAs) were p-coumaric acid (p-CoA) "109.35-261.77 µg/g", m-coumaric acid (m-CoA) "10.22-70.57 µg/g", and ferulic acid (FeA) "35.54-109.13 µg/g". The maximum percentage of PA was obtained in April "595.61 µg/g", while the maximum p-CoA content was obtained in January "261.77 µg/g". Therefore, the leaves can be recommended as the optimal source of PHAs. If there is a specific interest in certain PHA components, we recommend collection in either January or April. Multivariate statistical analysis (PCA & AHC) showed the existence of two main clusters. The first cluster comprised the leaves, distinguished by the highest VaA, PA, and p-CoA contents. The second cluster comprised roots and the root bark samples. This study provides information on the development of PHAs in different parts of Centaurea sp. and explores potential applications. It will be of considerable interest for determining the optimal harvesting time of shrub species used for their medicinal properties and bio-active phenolic contents.

Effect of Seasonal and Regional Variations on Phenolic Compounds of Deverra scoparia (Flowers/Seeds) Methanolic Extract and the Evaluation of Its in Vitro Antioxidant Activity.

The widespread use of Deverra scoparia Coss. & Durieu in Algerian folk-medicine as a remedy can be relatively attributed to its total phenolic compounds. The current study aimed to provide a scientific basis for optimal collection and usage of Deverra scoparia Coss. & Durieu plant. Hence, 37 samples were gathered from nine sites in Algeria during two seasons 2016 and 2017, then exposed to a green extraction. Total phenolic (TPC), flavonoid (FC) and condensed tannins (CTC) content were estimated spectrophotometrically. The antioxidant activity was measured using five different methods, DPPH. , ABTS.+ , FRAP, CUPRAC and Fe2+ -chelating. The results have revealed considerable amounts of TPC varied from 804 to 1544 mg GAE/100 g dry matter, FC started from 187 up to 410 mg QE/100 g dry matter and CTC varied from 111 to 394 mg CE/100 g dry matter. The best IC50 values (µg/mL) of DPPH. , ABTS•+ , FRAP, CUPRAC and Fe2+ -chelating tests were 56.62, 5.41, 21.26, 52.93 and 78.10, respectively. Moreover, high correlations were found between CTC and most of the antioxidant tests. Hence, CTC are suggested to be the principal group of antioxidant activity in Deverra scoparia Coss. & Durieu extracts.

Synergistic antinociceptive activity of combined aqueous extracts of Artemisia campestris and Artemisia herba-alba in several acute pain models.

In this study, total phenolic and flavonoid contents, acute toxicity and the antinociceptive activity of Artemisia campestris and Artemisia herba-alba, individually and in combination, were investigated using multiple forms of pain in animals. Our results have been shown that plants are relatively safe without clinical signs of toxicity in animals. Thus, extracts were presented high levels in phenolic and flavonoid contents. Artemisia decoctions with 100, 200, 400 mg/kg b-w studied dose, clearly attenuate chemical and thermal noxious stimuli in writhing, formalin and hot-plate tests, and significantly reduced paw oedema in formalin test. Additionally, binary combination forms exhibited a great improvement in intensity and amplitude of antinociceptive activity in comparison with both plants used individually by a relative interference with opioid system. Our findings suggested the central and peripheral analgesic properties and confirmed the folkloric medicinal use of these plants in pain symptom treatment.

Chemotypes of essential oil of unripe galls of Pistacia atlantica Desf. from Algeria.

The essential oils (EOs) of unripe galls (from male and female plants) of a total number of 52 samples of Pistacia atlantica collected from different regions in Algeria were analysed by GC/MS and GC. The yields of the extraction of the EO by hydrodistillation vary from low to high values (0.08-1.89% v/w). The results of both methods of principal component analysis and hierarchical ascendant classification revealed the presence of two different chemotypes: α-pinene chemotype and α-pinene/sabinene/terpinen-4-ol chemotype.

Chemical composition and antioxidant activity of seed oil of two Algerian date palm cultivars (Phoenix dactylifera).

The fatty acid composition of date seed oil from two different date palm (Phoenix dactylifera L.) cultivars, locally known as Degla-Baïdha and Tafezouine, were investigated. GC analysis revealed the presence of five dominant fatty acids: oleic C18:1 (46.51; 39.15%), lauric C12:0 (22.1; 28.5%), myristic C14:0 (10.7; 11.4%), palmitic C16:0 (9.6; 8.7%) and linoleic C18:2 (6.9; 6.1%). The oils was characterised by a low content of tocopherols (0.53; 1.41 µg/g). The antioxidant activity of the oils was investigated using the DPPH*(1,1-di-phenyl-2-picryl-hydrazyl) scavenging assay. The oils had a weak bleaching effect on DPPH* free radicals. This study showed that the qualities of the tested oils are highly comparable with those of some commercial seed oils of other plants. Furthermore, a statistical analysis using the hierarchy ascendant classification method was conducted in order to highlight the similarities and/or the differences regarding the contents of the main fatty acids found in some common plants and in the five most famous cultivars of Phoenix dactylifera of south eastern Algeria (Tafezouine, Degla-Baïdha, Deglet-Nour, Ghars, Tamdjouhert).

Chemical composition and antioxidant activity of the essential oil and fatty acids of the flowers of Rhanterium adpressum.

The essential oil obtained by hydrodistillation of the flowers of Rhanterium adpressum Coss. & Durieu was analyzed using GC and GC-MS. The essential oil was very rich in monoterpene compounds. The major components identified were the monoterpene hydrocarbons: camphene (21.8%), myrcene (19.3%) and alpha-pinene (17.4%). Other compounds, including limonene, beta-pinene and terpinol-4-ol, were present in low content (4-6%). The composition of the fatty acids in the lipid extract obtained from the flowers was also investigated by GC and GC-MS. The main fatty acids identified were palmitic (47.4%), oleic (12.9%) and stearic acids (10.6%). The total phenolic contents and the antioxidant activities were also evaluated for both extracts. The total phenolic contents were determined using the Folin-Ciocalteu reagent and the antioxidant activities were measured using three different assays: DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical scavenging activity, FRAP (ferric reducing antioxidant potential) and a molybdenum assay. As a result of these tests, the lipid extract exhibited the highest antioxidant activities in comparison with the essential oil extract.

Chemical composition of the essential oil of Pituranthos scoparius.

The essential oils obtained by hydro distillation of the aerial parts of Pituranthos scoparius were collected from different regions of Algeria and gave various yields ranging from 0.6 up to 2.8% (v/w). These samples were analyzed by GC and GC-MS showing the occurrence of monoterpene hydrocarbons and some oxygenated compounds. The major components were alpha-pinene (4.4-35.8%), limonene (0.8-66.5%), bornyl acetate (tr-9.6%), myristicin (tr-31.1) and dill apiole (0.4-47.3%). The aerial parts of P. scoparius could be either very rich or very poor in limonene, myristicin or dill apiole. Cluster analysis shows differences in essential oil compositions of samples coming from the different area collected.

Chemotypes of Pistacia atlantica leaf essential oils from Algeria.

The essential oils obtained by hydrodistillation of Pistacia atlantica Desf. leaves collected from different regions of Algeria were analyzed by GC and GC-MS. The essential oil was rich in monoterpenes and oxygenated sesquiterpenes. The major components were alpha-pinene (0.0-67%), delta-3-carene (0.0-56%), spathulenol (0.5-22%), camphene (0.0-21%), terpinen-4-ol (0.0-16%) and beta-pinene (0.0-13%). Among the various components identified, twenty were used for statistical analyses. The result of principal component analysis (PCA) showed the occurrence of three chemotypes: a delta-3-carene chemotype (16.4-56.2%), a terpinen-4-ol chemotype (10.8-16.0%) and an alpha-pinene/camphene chemotype (10.9-66.6%/3.8-20.9%). It was found that the essential oil from female plants (delta-3-carene chemotype) could be easily differentiated from the two other chemotypes corresponding to male trees.