Peels and edible pulp from three species of citrus including Citrus aurantifolia (varieties pica and sutil) and Citrus x lemon var. Genova widely cultivated and consumed in Northern Chile (I and II region) were analyzed for phenolic compounds and antioxidant activity for the first time. A high performance electrospray ionization mass spectrometry (HPLC-UV-ESI-MS) method was developed for the rapid identification of phenolics in extracts from peels and juices of all species. Several flavonoids including one kaempferol-O-hexoside (peak 16) and one hesperidin derivative (peak 22) three quercetin derivatives (peaks 4, 19 and 36), five isorhamnetin derivatives (peaks 5, 23, 24, 26 and 29) four luteolin derivatives (peaks 14, 25, 27 and 40), seven apigenin derivatives (peaks 2, 3, 12, 20, 34, 35 and 39), seven diosmetin derivatives (peaks 7–9, 17, 21, 31 and 37), three chrysoeriol derivatives (peaks 10, 18 and 30), and four eryodictiol derivatives (peaks 6, 13, 15 and 38) were identified in negative and positive mode using full scan mass measurements and MSⁿ fragmentations. Ascorbic acid content was higher in the pulps of the varieties Genova and Sutil (60.13 ± 1.28 and 56.53 ± 1.06 mg ascorbic acid per g dry weight, respectively) while total phenolic content was higher in Pica peels followed by Sutil peels (34.59 ± 0.81 and 25.58 ± 1.02 mg/g GAE dry weight, respectively). The antioxidant capacity was also higher for Pica peels (10.34 ± 1.23 µg/mL in the DPPH assay and 120.63 ± 2.45 µM trolox equivalents/g dry weight in the FRAP assay). The antioxidant features together with the high polyphenolic contents can support at least in part, the usage of the peel extracts as nutraceutical supplements, especially to be used as anti-ageing products.

Goji (Lycium barbarum L.) leaves are emphasized as a functional tea or as dietary supplements. The phenolic compound profile, antioxidant, enzyme inhibitory, antimicrobial, and antimutagenic activities of leaf extracts from two selected cultivars in comparison with wild-growing plants have been evaluated. HPLC-DAD/ESI-ToF-MS analysis revealed the presence of phenolic acids and flavonoids with chlorogenic acid and rutin being the dominant compounds in the cultivated plants, whereas rutin and kaempeferol-3-O-rutinoside for wild growing ones. In particular, cv. Erma contained the highest amount of chlorogenic acid and showed a strong tyrosinase-inhibitory effect. Staphylococcus aureus, Listeria monocytogenes, and Penicillium funiculosum were the most sensitive strains when exposed to extracts from cultivated plants. Antimutagenic activity was evaluated by Ames' test. The tested extracts provided high protection against mutagenicity induced by 2-anthramine (2-AA) to Salmonella typhimurium strains TA 98 and TA 100 (max. inhibition (%) 88% and 74.2%, respectively). Overall, Goji leaves are a rich source of bioactive compounds with functional properties that need further risk/benefit evaluation when used in foods or health-promoting formulations.

The banana passion fruit (Passiflora tripartita Breiter, Passifloraceae) known as “tumbo” is very appreciated in tropical and subtropical countries of South America. Methanolic extracts from peel and the fruit juice of P. tripartita growing in Chile were analyzed for antioxidant capacity as well as for flavonoid and phenolic content. A chromatographic method was developed for the rapid identification of the main phenolics in the samples by HPLC-DAD and HPLC-MS. The fast fingerprint analysis allowed the detection of eighteen flavonoid C-glycosides and four flavonoid O-glycoside derivatives which were characterized by UV spectra and ESI-MS-MS analysis. Several of the C-glycosides detected are structurally related to the orientin derivative 4′-methoxy-luteolin-8-C-(6″acetyl)-b-D-glucopyranoside (31), fully elucidated by spectroscopic methods. The antioxidant derivative 31 along with schaftoside, vicenin II, orientin and vitexin were isolated from the fruit extract by high-speed countercurrent chromatography (HSCCC). A suitable method for the preparative isolation of flavonol C-glycosides from “tumbo” extracts by HSCCC is reported. The pulp of the fruits showed good antioxidant capacity (12.89 ± 0.02 mg/mL in the DPPH assay). The peel presented the highest content of flavonoids (56.03 ± 4.34 mg quercetin/100 g dry weight) which is related to the highest antioxidant power (10.41 ± 0.01 mg/mL in the DPPH assay).

The antioxidant features, polyphenolic composition and chromatographic fingerprints of the aerial parts from three Chilean endemic plants from the Paposo Valley located on the cost of the Atacama Desert were investigated for the first time using high pressure liquid chromatography coupled with photodiode array detector and electrospray ionization mass analysis (HPLC-PDA-ESI-MS) and spectroscopic methods. The phenolic fingerprints obtained for the plants were compared and correlated with the antioxidant capacities measured by the bleaching of the DPPH radical, the ferric reducing antioxidant power (FRAP) and quantification of the total content of phenolics and flavonoids measured by spectroscopic methods. Thirty phenolics were identified for the first time for these species, mostly phenolic acids, flavanones, flavonols and some of their glycoside derivatives, together with three saturated fatty acids (stearic, palmitic and arachidic acids). Nolana ramosissima showed the highest antioxidant activity (26.35 ± 1.02 μg/mL, 116.07 ± 3.42 μM Trolox equivalents/g dry weight and 81.23% ± 3.77% of inhibition in the DPPH, FRAP and scavenging activity (SA) assays, respectively), followed by N. aplocaryoides (85.19 ± 1.64 μg/mL, 65.87 ± 2.33 μM TE/g DW and 53.27% ± 3.07%) and N. leptophylla (124.71 ± 3.01, 44.23 ± 5.18 μM TE/g DW and 38.63% ± 1.85%).