The genus Vaccinium contains about 400 species distributed worldwide, but only a few species and varieties have had their phenolic composition and biological activity documented. In this study, phenols, flavonoids, anthocyanins, antioxidant and antimicrobial activity of methanolic extracts of Vaccinium stenophyllum Steud. fruits: 1-totally immature, 2-immature, 3-immature/close to maturity and 4-mature, were determined using UV-Visible spectrometry and HPTLC. The totally immature fruit extract showed the highest content of total phenols (19.153 ± 0.175 mg GAE/g DW), chlorogenic acid (20.867 ± 0.240 mg CAE/g DW), and the highest antioxidant activity by ABTS^●+ (196.761 ± 0.641 µM TE/g DW) and DPPH^● (146.580 ± 6.466 µM TE/g DW). Immature, immature/close to maturity and mature fruits extracts, exhibited the lowest MIC (9.37 mg/mL) and MBC (18.75 mg/mL) against Escherichia coli, Salmonella choleraesuis, and Shigella flexneri. The mature fruits extract exhibited the highest content of total anthocyanins (0.141 ± 0.004 mg CE/g DW) and cyanidin-3-glucoside (19.230 ± 0.309 mg CGE/g DW). The content of phenols, flavonoids and anthocyanins was higher than that reported for other Vaccinium species. These results showed the relevance of Vaccinium stenophyllum Steud. for breeding purposes to enhance the bioactivity of cultivars, or as a source of natural additives for the food industry, among others.

Around 450 species of blueberries of the genus Vaccinium are known, of which some have gained preferential breeding, such as the ‘Biloxi’ variety. Some little studied species, such as Vaccinium leucanthum Schltdl. located in Mexico, could be a potential source of bioactive compounds. In this study, the phenolic compounds (chlorogenic acid content, hyperoside, phenols, flavonoids, tannins and total anthocyanins content) as well as the potential biological activity (antioxidant, antimicrobial, xanthine oxidase converting enzyme inhibition and angiotensin I inhibition) of Vaccinium leucanthum Schltdl. were studied, making a comparison with the Biloxi variety, which is the most widely cultivated one. The extract of V. leucanthum showed the highest content of flavonoids (4.853 ± 0.341 mg QE/g DW), total anthocyanins (0.303 ± 0.008 mg CGE/g DW), petunidin-3-glucoside (6.92 ± 0.12 mg PGE/g DW), malvidin-3-glucoside (11.80 ± 0.10 mg MGE/g DW) and hyperoside (5.137 ± 0.100 mg HE/g DW). It should be noted that V. leucanthum showed the same total tannin content and the same efficacy in the inhibition of Angiotensin I-converting enzyme as ‘Biloxi’, as well as the same antibacterial effect against the enterobacteria Salmonella choleraesuis ATCC 12022, Escherichia coli ATCC 12792and Shigella flexneri ATCC 10708. These findings demonstrate that V. leucanthum extracts could be an important source of preservatives as well as nutraceutical compounds for use in foods and medicines.

Psittacanthus calyculatus is a hemiparasitic plant of an arboreal species (e.g., forest, fruit trees). Its foliage has therapeutic potential; however, little is known about its fruits. In this study, the phytochemical profile and biological activities of P. calyculatus fruits hosted by Prosopis laevigata and Quercus deserticola were evaluated. The fruits of P. calyculatus from P. laevigata showed the highest content of total phenols (71.396 ± 0.676 mg GAE/g DW). The highest content of flavonoids and anthocyanins was presented in those from Q. deserticola (14.232 ± 0.772 mg QE/g DW; 2.431 ± 0.020 mg C3GE/g DW). The anthocyanin cyanidin-3-glucoside was detected and quantified via high-performance thin-layer chromatography (HPTLC) (306.682 ± 11.804 mg C3GE/g DW). Acidified extracts from host P. laevigata showed the highest antioxidant activity via ABTS^•+ (2,2′azinobis-(3-ethylbenzothiazdin-6-sulfonic acid) (214.810 ± 0.0802 mg TE/g DW). Fruit extracts with absolute ethanol from the P. laevigata host showed the highest antihypertensive activity (92 ± 3.054% inhibition of an angiotensin converting enzyme (ACE)). Fruit extracts from both hosts showed a minimum inhibitory concentration (MIC) of 6.25 mg/mL and a minimum bactericidal concentration (MBC) of 12.5 mg/mL against Escherichia coli, Salmonella choleraesuis and Shigella flexneri. Interestingly, a significant host effect was found. P. calyculatus fruits extract could be used therapeutically. However, further confirmation experiments should be carried out.