Phytochemical Analysis and Biological Activities of Ripe Fruits of Mistletoe (Psittacanthus calyculatus).

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.

Dynamics of Polyphenol Biosynthesis by Calli Cultures, Suspension Cultures and Wild Specimens of the Medicinal Plant Ligaria cuneifolia (Ruiz & Pav.) Tiegh. (Loranthaceae). Analysis of Their Biological Activity.

Ligaria cuneifolia (R. et P.) Tiegh. (Loranthaceae) is a South American hemiparasitic species with antioxidant, antitumoral, antimicrobial, and antilipidemic activities attributed to its polyphenolic content. We studied the polyphenolic pattern of L. cuneifolia during different phenological stages: flowering, fruiting, and post-fruiting. The highest total phenolic content was found in stems at post-fruiting (214 ± 12.1 mg gallic acid eq·g-1 DW) and fruiting (209 ± 13.7 mg gallic acid eq·g-1 DW), followed by post-fruiting leaves (207 ± 17.5 mg gallic acid eq·g-1 DW). Flavonoids accumulated at higher levels in leaves and hydroxycinnamic acids in leaves at flowering and post-fruiting. The polyphenolic pattern was similar between organs from wild plants and in vitro cultures, although at a significantly lower level in the latter ones. The performance of calli growing under a 16 h photoperiod in a modified White medium with 1-naphthalene acetic acid (2.50 µM) and Kinetin (9.20 µM) was better than in the dark. When calli grew in media only with auxins (IAA, NAA, and 2,4-D, all at 2.50 µM concentration), its growth and polyphenolic content improved. Cell suspensions with 2.50 µM NAA and 9.20 µM KIN grew slowly and produced very small amounts of polyphenols. As for the antioxidant activity, it was detected in all samples (approximately 1000 µmol trolox eq·g-1 DW) except fruits, where a lower value was found (328 µmol trolox eq·g-1 DW). In vitro cultures have the lowest antioxidant activity when compared to methanolic extracts from organs of wild specimens. Finally, antimutagenic or mutagenic activity in wild plants and in vitro culture extracts was not detected by the Ames test.

The ecophysiology of a neotropical mistletoe depends on the leaf phenology of its tree hosts.

PREMISE: Mistletoes parasitize many hardwood and softwood tree species; however, they play key roles in forest ecosystems. Adult individuals of Psittacanthus schiedeanus take up water and xylem nutrients from both deciduous and evergreen host trees, suggesting the ability to modify its physiology according to the availability of host resources. Yet, there is little information regarding the effects of mistletoes on their host trees from the eophyll stage to reproductive phases of the parasite. METHODS: Taking advantage of the fact that P. schiedeanus can reach sexual maturity in 1 year, we investigated its physiological performance during development on deciduous (Liquidambar styraciflua) and evergreen (Quercus germana) host trees in a cloud forest in eastern Mexico. Variables related to chlorophyll fluorescence, carbon assimilation, photosynthetic pigments, and nitrogen, phosphorus, and carbon contents of the parasite and non-infected and infected hosts were analyzed in a nursery experiment. RESULTS: Mistletoe had lower water-use efficiency and higher transpiration rates than the host species did. Despite the fact that P. schiedeanus obtained resources from species with differing phenology and resource availability, the parasite steadily improved its CO2 assimilation, electron transport rate, and nutrient content from seedling establishment to adult life stages. Mistletoe decreased the photosynthetic reactions of carbon metabolism in the deciduous host, photosynthetic light reactions in the evergreen host, and nutritional status of both host species, mostly in the evergreen host. CONCLUSIONS: The hypothesis that mistletoes adjust their physiology according to the availability of host resources could extend to the early growth of the parasite.

CERVANTESIACEAE: NUEVO REGISTRO DE UNA FAMILIA NATURALIZADA PARA LA FLORA DE MÉXICO / Cervantesiaceae: New Record of a Naturalized Family for the Flora of Mexico

Se registra por primera vez para México la especie naturalizada Acanthosyris glabrata (familia Cervantesiaceae), un árbol hemiparásito sólo conocido del noroeste de Sudamérica. Se proporciona información sobre su hábitat y se presenta una ilustración de la especie. Se propone una hipótesis de comercio maritimo entre Ecuador y México para explicar la presencia del taxón en el occidente de México, en un área que dista 3500 km de su distribución original.

We register for the first time in Mexico the naturalized species Acanthosyrisglabrata (family Cervantesiaceae), a hemiparasitic tree only known from northwestern South America. We provide information about its habitat and present an illustration of the species. We propose a hypothesis of maritime commerce between Ecuador and Mexico to account for the presence of the taxon in western Mexico, in an area 3500 km away from its original known distribution.

Leaf morphophysiology of a Neotropical mistletoe is shaped by seasonal patterns of host leaf phenology.

Several mistletoe species are able to grow and reproduce on both deciduous and evergreen hosts, suggesting a degree of plasticity in their ability to cope with differences in intrinsic host functions. The aim of this study was to investigate the influence of host phenology on mistletoe water relations and leaf gas exchange. Mistletoe Passovia ovata parasitizing evergreen (Miconia albicans) hosts and P. ovata parasitizing deciduous (Byrsonima verbascifolia) hosts were sampled in a Neotropical savanna. Photosynthetic parameters, diurnal cycles of stomatal conductance, pre-dawn and midday leaf water potential, and stomatal anatomical traits were measured during the peak of the dry and wet seasons, respectively. P. ovata showed distinct water-use strategies that were dependent on host phenology. For P. ovata parasitizing the deciduous host, water use efficiency (WUE; ratio of photosynthetic rate to transpirational water loss) was 2-fold lower in the dry season than in the wet season; in contrast, WUE was maintained at the same level during the wet and dry seasons in P. ovata parasitizing the evergreen host. Generally, mistletoe and host diurnal cycles of stomatal conductance were linked, although there were clear differences in leaf water potential, with mistletoe showing anisohydric behaviour and the host showing isohydric behaviour. Compared to mistletoes attached to evergreen hosts, those parasitizing deciduous hosts had a 1.4-fold lower stomatal density and 1.2-fold wider stomata on both leaf surfaces, suggesting that the latter suffered less intense drought stress. This is the first study to show morphophysiological differences in the same mistletoe species parasitizing hosts of different phenological groups. Our results provide evidence that phenotypical plasticity (anatomical and physiological) might be essential to favour the use of a greater range of hosts.

SEED GERMINATION AND PLANT DEVELOPMENT IN Escobedia grandiflora (OROBANCHACEAE): EVIDENCE OF OBLIGATE HEMIPARASITISM? / Germinación de semillas y desarrollo de plantas en Escobedia grandiflora (Orobanchaceae): ¿Evidencia de hemiparasitismo obligado?

Root parasitic plants can be facultative or obligate. Facultative parasites are able to complete their life cycle and their seeds can germinate without a host. Escobedia grandiflora is a poorly studied species in spite of its ancestral importance as dye of foods and medicinal use. The present study evaluates the states of seed, seedlings and mature plants, under presence and absence of possible hosts, for inferring the type of parasitism exhibited by E. grandiflora. Seeds were evaluated using two conditions each of light (12 and 0 hours) and temperature (20 °C and 25 °C); percentage germination, and germination speed were determined. The seeds did not require a host to germinate, as is typical of facultative parasitic plants. Percentage of germination varied between 66 % and 85.3 % and was not affected by light or temperature although germination speed was greater at 25 °C. Larger seeds had a higher percentage of germination and produced larger seedlings. The seedlings planted without a host did not survive, while those planted with Paspalum notatum had a 45 % survival rate, demonstrating that this is a critical stage of development, even with a host. Escobedia grandiflora plants sowed with grasses began the reproductive stage at the 28th week, and those planted with Pennisetum purpureum showed better performance, expressed in more haustoria, higher dry matter of total plant, rhizome and aerial stems. Plants sowed alone lived for more than six months, but they did not produce flowers or fruits. According to the behavior of seedlings and plants, E. grandiflora is an obligate parasite.

Las plantas parásitas de raíces pueden ser facultativas u obligadas, las primeras pueden completar su ciclo de vida y sus semillas pueden germinar sin un hospedero. Escobedia grandiflora es una especie poco estudiada, a pesar de su importancia ancestral como colorante de alimentos y uso medicinal. Este estudio evaluó los estados de semilla, plántula y planta adulta, en presencia y ausencia de posibles hospederos para inferir sobre su tipo de parasitismo. En las semillas se evaluaron dos condiciones de luz (12 y 0 horas) y temperatura (20 °C y 25 °C), el porcentaje y velocidad de germinación. Las semillas no requirieron la presencia del hospedero para germinar. El porcentaje de germinación osciló entre 66 y 85,3 % y no fue afectado por la luz o la temperatura, aunque la velocidad de germinación fue mayor a 25 °C. Las semillas con mayor tamaño presentaron mayor porcentaje de germinación y produjeron plántulas más grandes. Las plántulas sembradas sin hospedero no sobrevivieron, mientras que las sembradas con Paspalum notatum, tuvieron una sobrevivencia del 45 %, evidenciando que este estado es crítico, aún con hospedero. Las plantas de Escobedia grandiflora sembradas con pastos, iniciaron la etapa reproductiva en la semana 28, y aquellas sembradas con Pennisetum purpureum presentaron más haustorios, y mayor materia seca en la planta total, rizoma y tallos aéreos. Las plantas sembradas solas vivieron más de seis meses, pero ellas no desarrollaron flores y ni frutos. Según el comportamiento de las plántulas y las plantas, E. grandiflora es parásita obligada.

Development and characterization of microsatellite loci in the mistletoe Psittacanthus schiedeanus (Loranthaceae).

PREMISE OF THE STUDY: Microsatellite primers were developed for the parasitic Psittacanthus schiedeanus, a common mistletoe species on cloud forest-adapted tree hosts in Mesoamerica, to investigate intraspecific genetic patterns of diversity and genetic structure. • METHODS AND RESULTS: Using an enriched library, 10 polymorphic microsatellite loci were developed in P. schiedeanus. All loci consisted of dinucleotide repeats. Average alleles per locus were 12 (4-17), and a total of 120 alleles were recorded across 39 individuals from four populations in Mexico. Primers were tested in 11 additional species, but only amplified successfully in P. calyculatus and P. angustifolius. • CONCLUSIONS: The polymorphic loci described will be useful in studies of genetic diversity and genetic population differentiation in natural populations of these parasitic plants, and will provide valuable information to understand the importance of host distribution.