Development of a preliminary extraction protocol for phenol compounds during table grape grafting formation

The development of rootstocks that are less sensitive to abiotic and biotic stresses can help mitigate the negative effects of climate change on crop productivity, soil health, and water use. Though, the phenomenon of graft incompatibility is a significant limitation to the spread of new rootstock genotypes. Numerous studies have focused on this issue, highlighting the role of certain phenolic molecules as predictive markers of incompatibility. Given the lack of specific research on table grape, , this study proposes a protocol for the extraction of polyphenols from its woody tissues, which is a fundamental prerequisite for further analysis on secondary metabolites involved in graft incompatibility. The proposed eco-friendly method coupled a traditional maceration using solvent with a green technique utilizing an ultrasound-assisted extractor. The following parameters were compared: (1) sample weight (0.1 g, 0.5 g, and 1 g), (2) time of ultrasound-assisted extraction (10 min, 20 min, and 30 min), and (3) solvent volume for maceration (10 mL, 15 mL, and 20 mL). Four phenol classes were considered based on previous works on Vitis spp.: cinnamic acids, flavonols, benzoic acids, and catechins. The characterization of polyphenolic biomarkers was carried out via HPLC. 1 g of plant material, 30 minutes of sonification, and 20 mL of organic solvent was the combination of factors that resulted in the most efficient fingerprint, both quantitatively (267.68 ± 3.91 mg/100 g fresh weight [FW]) and qualitatively, with the four classes analyzed significantly represented. This is the first work to come up with an extraction protocol for phenol compounds in table grape woody tissue based on both ecological and routine techniques

Antioxidant, Anti-Inflammatory, and Antidiabetic Activities of Leaves and Stems of Uapaca bojeri Bail.(EUPHORBIACEAE), an Endemic Plant of Madagascar

Uapaca bojeri is an endemic Malagasy plant used by the local population. This work aimed to evaluate antioxidant, anti-inflammatory, and antidiabetic activities of the methanol extracts of U. bojeri leaves and stems and to report their total phenolic content and the bioactive compound content by HPLC methods. Antioxidant capacity was determined by DPPH and ferric reducing antioxidant power (FRAP) assays. An in vivo carrageenan-induced paw oedema and acetic acid-induced writhing test in mice were used for anti-inflammatory activity evaluation. An oral glucose tolerance test was performed in mice to evaluate antidiabetic activity. The total bioactive compound content of leaves was higher than that of stems. Stem methanol extract inhibited the free radical DPPH more than the leaf methanol extract. Leaf methanol extract inhibited, in a dose-dependent manner, the carrageenan-induced paw oedema more than the stem extract, but their inhibition of the pain symptoms caused an acetic acid-induced decrease similar to the number of writhes in the dose-dependent case. The leaf and stem methanol extracts significantly reduced blood glucose levels after 30 min of glucose loading in mice compared to the control group blood glucose reduction. The presence of several bioactive compounds in U. bojeri contributed to the different biological activities, but isolation and identification of these bioactive molecules are necessary to confirm these pharmacological properties

Quali-Quantitative Study on Phenol Compounds as Early Predictive Markers of Graft Incompatibility: A Case Study on Chestnut (<i>Castanea</i> spp.)

In recent years, research has focused on phenolic compounds and their putative role as markers of graft incompatibility. Thus far, no studies have been conducted on the role of phenolic compounds in chestnut (Castanea spp.). The present study investigated the content of phenolic compounds in different combinations of Castanea spp. cultivars and rootstocks. Analyses were performed on the inner and outer tissues of chestnut grafts at two phenological sampling stages. The separation, identification and quantification of the phenolic markers via HPLC were preceded by an ultrasonic green extraction. Two chromatographic methods were tested for a total of 15 phenol compounds. Flavonol compounds were not detected, while cinnamic acids were found in low concentrations. The amount of gallic acid turned out to be higher at the graft union of the incompatible combination (20.11 ± 1.47 mg/100 gFW vs. 8.94 ± 1.08 mg/100 gFW). The same pattern was observed for catechin (15.79 ± 1.83 mg/100 gFW vs. 9.63 ± 1.98 mg/100 gFW). Differences in tannin concentrations seemed to be species-specific, and were apparently not related to graft incompatibility. The present work underlines the potential application of certain phenol compounds for the early prediction of graft incompatibility in Castanea spp

Quali-Quantitative Study on Phenol Compounds as Early Predictive Markers of Graft Incompatibility: A Case Study on Chestnut (Castanea spp.)

In recent years, research has focused on phenolic compounds and their putative role as markers of graft incompatibility. Thus far, no studies have been conducted on the role of phenolic compounds in chestnut (Castanea spp.). The present study investigated the content of phenolic compounds in different combinations of Castanea spp. cultivars and rootstocks. Analyses were performed on the inner and outer tissues of chestnut grafts at two phenological sampling stages. The separation, identification and quantification of the phenolic markers via HPLC were preceded by an ultrasonic green extraction. Two chromatographic methods were tested for a total of 15 phenol compounds. Flavonol compounds were not detected, while cinnamic acids were found in low concentrations. The amount of gallic acid turned out to be higher at the graft union of the incompatible combination (20.11 &plusmn; 1.47 mg/100 gFW vs. 8.94 &plusmn; 1.08 mg/100 gFW). The same pattern was observed for catechin (15.79 &plusmn; 1.83 mg/100 gFW vs. 9.63 &plusmn; 1.98 mg/100 gFW). Differences in tannin concentrations seemed to be species-specific, and were apparently not related to graft incompatibility. The present work underlines the potential application of certain phenol compounds for the early prediction of graft incompatibility in Castanea spp

Chemical composition, antimicrobial activity, and antioxidant capacity of Micromeria flagellaris Baker and M. madagascariensis Baker: Two endemic species from Madagascar as sources of essential oils

Background: The aerial parts of Micromeria madagascariensis Baker and M. flagellaris Baker are used by the population of the Vakinankaratra and Itasy regions (Madagascar) to treat breathing difficulty, fever and/or headache, wounds, and sores. Purpose: This work aimed to characterise plant materials from M. madagascariensis and M. flagellaris to report i) chemical composition, ii) antimicrobial properties, and iii) antioxidant capacity of the essential oils extracted from the aerial parts of these species. Materials and methods: The essential oils from M. madagascariensis (MMO) and M. flagellaris (MFO) were obtained by hydrodistillation. Their chemical composition was quantified using gas chromatography coupled with mass spectrometry (GC-MS). MMO and MFO were also tested against 7 microbial strains using the disk diffusion method and their antioxidant capacity was assessed using the DPPH scavenging assay. Results: Hydrodistillation yielded 0.26% MMO and 0.29% MFO (w/w) in relation to the fresh weight. Twenty-seven compounds were identified by GC-MS in MMO extract against 36 in MFO one. The main compounds in MMO were pulegone (24.67%), trans-menthone (24.67%), eucalyptol (8.12%), β-caryophyllene (4.98%), α-guanene (4.47), iso-menthone (3.85%), iso-pulegone (3.34%), azulene (3.28%) and 2-isopropyl-5-methylcyclohexenone (2.82%). The main compounds in the MFO were eudesma-4,11-dien-2-ol (13.88%), δ-guanene (6.62%), pulegone (6.40%), cyperone (5.56%), 4-epi-dehydrobietinol acetate (5.39%), eucalyptol (5.12%), trans-menthone (4.67%), limonene (3.77%) and sabinene (2.29%). Regarding the chemotaxonomy, M. flagellaris was very different from M. madagascariensis and both species also differed from the other Micromeria species, as confirmed by multivariate statistical analysis. Both MMO and MFO exerted activities against a large microbial spectrum; the antimicrobial activity of MMO was higher than MFO one against S. pneumoniae and C. albicans due to the presence of pulegone as the main component. MFO showed an excellent scavenging capacity with an SC50 value of 2.17 ± 0.03 μg/mL. Conclusion: The biological properties of the essential oils extracted from the selected species may explain their therapeutic value showing that Malagasy Micromeria species may be very important as new natural sources of bioactive compounds. This study may promote the effectiveness and quality of Malagasy Micromeria species, contributing to sustainable development and commercial valorisation of traditional preparations based on natural local resources