Microencapsulation of an Extract of Sechium edule (Jacq.) Sw., with Antineoplastic Activity

Microencapsulation is a technique used in pharmaceuticals as an administration vehicle. Encapsulating secondary metabolites for therapeutic purposes has been promoted recently. Microencapsulation based on chitosan was developed for the methanol extract of cv. Perla negra (S. edule (Jacq.) Sw.) (Cucurbitaceae) fruits to evaluate its viability as an administration vehicle and to assess the possible negative interaction between the extract and chitosan. Microencapsulation was performed by coacervation, implementing a method with constant sonication. The microparticles obtained were registered by means of Scanning Electron Microscopy. The presence of the bioactive in aqueous medium was recorded for release tests, measuring with spectrophotometry its concentration as a function of time. The assessment of the biological effect of the microencapsulated extract was done on the HeLa cell line and control cells (lymphocytes). Microspheres with an average size of 20 µm and a loading capacity of 98% were obtained. The highest concentration of released extract was 24 µg mL−1 at 23 h. The mainly chitosan-based microspheres did not affect the antiproliferative activity of the extract of cv. Perla negra and proved to be a potential vehicle for its therapeutic administration. The empty microspheres made with chitosan also showed to have an antiproliferative effect, and those loaded with extract showed cellular inhibition (statistical IC50) of 8 µg mL−1 without affecting the lymphocytes. Chitosan does not interfere with the biological activity of the metabolites incorporated into the microspheres since they retain their inhibitory activity on proliferation in tumor cells, thus constituting a potential vehicle for the therapeutic administration of fruit extract.

Distribution update, male genitalia, natural history, and conservation of the stump-tailed porcupine Coendou rufescens in South America

The stump-tailed porcupine, Coendou rufescens, is a widely distributed but scarcely documented species inhabiting the Andean region of Colombia, Ecuador, Peru, and an isolated population in Bolivia. Despite the wide distribution different aspects on its biology and ecology are still unknown. We present an update to the distribution of C. rufescens, and recent observations on the anatomy, natural history, and conservation in Colombia. For this, we described the male genitalia and present data on reproductive periods, plants used and consumed, and threats. The distribution of C. rufescens comprises 12 ecoregions in an area of 376,225 km2 for the northern group (Colombia, Ecuador, and Peru) and 393 km2 for the southern group (Bolivia). The highest elevational record is in Ecuador (4387 m), being the porcupine inhabiting at highest elevations. The anatomy of the glans is similar to that observed in Coendou quichua and constitutes the second species of Coendou with available information on glans morphology. C. rufescens consumes fruits and leaves of potato cider (Sechium edule: Cucurbitaceae) and woody shrub (Bejaria: Ericacea), and usually perches even in exotic species such as pines. Finally, common treats for the species in Colombia are related to hunting pressures, predation by domestic dogs, and roadkills.

GENETIC VARIABILITY IN Sechium spp. (Cucurbitaceae) EVALUATED WITH AFLP MARKERS

There are few studies in Mexico aimed at evaluating the genetic variability of Sechium spp. Despite certain biological variants are reported with very high potential to develop antineoplastic supplements to treat public health conditions. Using the Amplified Fragment Length Polymorphism (AFLP) technique, the genetic variability of a sample of 95 accessions of three species of Sechium (S. edule, S. chinantlense, S. compositum) was evaluated, with leaf DNA from the Banco Nacional de Germoplasma de Sechium edule en Mexico. Four combinations of AFPL were applied (EcoRI + ACC/MseI + CAC, EcoRI + ACC/MseI + CAT, EcoRI + ACC/MseI + CGC, and EcoRI + ACC/MseI + CGG). DNA samples were classified into three groups based on the flavour of the fruit (sweet, neutral, bitter). An average of 47.91% polymorphism, 0.16 heterozygosity, 32.83 number of polymorphic bands, and a zero Wright fixation index (Fst) was obtained. The evidence showed that the domesticated accessions (sweet, neutral) were separated from the bitter-taste genotypes. A monophyletic tree was generated with the genetic distance matrix and the neighbour-joining methodology. Analyses showed S. edule as the root taxon, deriving S. compositum and S. chinantlense as subgroups, and suggesting that there is not enough differentiation to treat them as separate species. The evaluated sample showed that there is no apparent reproductive barrier for genetic cross breeding. Genotypes behaved as a complex with evolutive dynamism; that genetic complexity would allow the design of new variants.

Impact of Encapsulation Wall Materials and Drying Method on Physicochemical Properties and Digestibility of Encapsulated Chayote (Sechium edule (Jacq.) Swartz) and Kohlrabi (Brassica oleracea var gongylodes L.) Extracts

Chayote (Sechium edule (Jacq.) Swartz) and kohlrabi (Brassica oleracea var gongylodes L.) are medicinal plants widely distributed in Thailand. Several traditional medicines usually contain these extracts due to their pharmaceutical activities. However, appropriate technologies that are used for protection, stabilization, and slow release of plant extracts are a lot desired in terms of food application. In this study, chayote and kohlrabi extracts were encapsulated by several kinds of wall materials (maltodextrin, and the combination of maltodextrin and gum arabic or alginate) and drying methods (freeze-drying and tray-drying techniques). Thus, the objective of this research was to determine morphological and physicochemical properties, wall materials releasing, and antioxidant activity of encapsulated chayote and kohlrabi extracts powder. The morphology of all encapsulated chayote and kohlrabi extracts powder showed irregular spherical shape, monodispersity, and smooth surface. The encapsulated chayote and kohlrabi extracts powder with tray-drying technique tend to have more darkness and redness in color than the freeze-drying technique. Wall material releasing was expressed in glucose liberation of encapsulated extracts powder after amylolytic enzyme digestion. Encapsulation using maltodextrin as wall material provided higher wall material releasing than the other samples. After digestion analysis, the digested residues were examined for antioxidant activity. The results showed that the combination of maltodextrin and alginate for both freeze-drying and tray-drying techniques provided higher antioxidant activity after 60 and 120 min of digestion. Thus, the combination of maltodextrin and alginate, and drying with the freeze-drying technique was the best treatment in this experiment. This data can lead to a better understanding of wall materials types and releasing characteristics, which are used to control bioactive compounds liberation in the gastrointestinal tract.

The effect of chayote leaves (Sechium edule)’s flavonoid fraction on the reduction of the serum uric acid levels through the inhibition of xanthine oxidase activity

Uric acid is the final product of purine metabolism and is categorized as hyperuricemia when it reaches >6.0 mg.dL-1 for women and >7.0 mg.dL-1 for men. The chayote leaves (Sechium edule) contain a high amount of flavonoid and might be used as an alternative to reduce hyperuricemia. The purpose of this study is to analyze the effect of chayote leaves (Sechium edule)’s flavonoid fraction on the level of uric acid and the activity of xanthine oxidase (XO) in Sprague Dawley Rats. The flavonoid fraction (FF) was obtained by extracting the chayote leaves, fractionating with n-hexane, hydrolyzing with HCl, and finally re-fractionating with ethyl acetate. Thirty male Sprague Dawley rats were induced for hyperuricemia by potassium oxonate and broth block for 21 days, and the interventions were given orally for 14 days. The rats were divided randomly into five groups: normal control (K-), hyperuricemia control (K+), hyperuricemia with FF dose 50 mg.200g-1 body weight (P1), hyperuricemia with FF dose 100 mg.200g-1 body weight (P2) and hyperuricemia with allopurinol 1.8 mg.200g-1 body weight. Xanthine oxidase activity was measured by CheKineTM Xanthine Oxidase Assay Kit, with simple colorimetry methods. The statistical analysis for XO activity was done using Kruskal-Wallis followed by Mann Whitney. The results showed that chayote leaves (Sechium edule)’s flavonoid fraction contains apigenin, apigenin o-glucoside, and luteolin. It also has antioxidant activity with 98.45% inhibition. There was a significant reduction in xanthine oxidase activity in groups treated with FF (p <0.005). The best dose of FF affecting XO activity was 100 mg.200g-1 body weight. The combination of FF and allopurinol can be more effective in decreasing uric acid levels by inhibiting XO activity.

OBTENCIÓN DE ETANOL A PARTIR DE SÓLIDOS SOLUBLES DE Sechium edule, EMPLEANDO Saccharomyces cerevisiae PARA LA FERMENTACIÓN.

Los biocombustibles, como el etanol, actualmente se han convertido en una alternativa para la generación de energía más amigable con el medio ambiente, pero su producción ha presentado una serie de inconvenientes dentro de los que se encuentran el uso de materias primas de origen alimenticio como el maíz y la caña de azúcar, por lo tanto es necesaria la búsqueda de alternativas para su producción; Sechium edule (cidra) es una fruta que posee buenos contenidos de azúcares, almidón y celulosa, se encuentra en la región cafetera y no es considerada un alimento básico. Por lo anterior en este trabajo se pretendió generar bioetanol partiendo de los sólidos solubles (SS), usando Saccharomyces cerevisiae como agente fermentador. El rendimiento de etanol obtenido fue de 52,18mL/100g de SS y se determinó su pureza por espectrometría infrarroja.

Flavonoid fraction from chayote (Sechium edule (Jacq.) Sw) leaves reduced malondialdehyde (MDA) and tumor necrosis factor-α (TNF-α) in hyperuricemic rats

Purpose This paper aims to study the effect of the flavonoid fraction of chayote (Sechium edule (Jacq.) Sw) leaves (FFCL) on uric acid (UA) levels, oxidative stress and inflammatory markers in hyperuricemia rats. Design/methodology/approach In total, 30 Sprague–Dawley rats were divided randomly into 5 groups. A healthy control group was established. Hyperuricemia was induced by the administration of block broth and potassium oxonate for three weeks. FFCL at dosages of 50 and 100 mg/200 g BW/d or allopurinol at a dosage of 1.8 mg/200 g BW/d was given orally for 2 weeks. Statistical analysis was conducted to evaluate differences among groups before and after the intervention. Findings Treatment with two different doses FFCL (50 and 100 mg/200 g BW/d) and one dose of allopurinol (1.8 mg/200 g BW/d) for 2 weeks significantly reduced UA from 8.04 ± 0.23 to 3.88 ± 0.10; 8.03 ± 0.18 to 2.87 ± 0.10; 8.23 ± 0.21 to 2.53 ± 0.19 (p < 0.05), respectively. The oxidative stress marker malondialdehyde levels were reduced (p = 0.001) from 9.68 ± 0.28 to 4.06 ± 0.58; 10.01 ± 0.23 to 2.12 ± 0.09; 9.88 ± 0.21 to 2.02 ± 0.17 (p = 0.001). The inflammatory marker tumor necrosis factor-α (TNF-α) levels were also reduced from 26.43 ± 0.87 to 12.20 ± 0.32; 27.38 ± 0.53 to 9.60 ± 0.53; 27.55 ± 0.68 to 8.83 ± 0.21 with p = 0.001. The 100 mg/200 g BW/d FFCL decreased UA levels, oxidative stress and inflammatory markers more extensively compared to 50 mg/200 g BW/d FFCL. Research limitations/implications This study includes some limitations that may affect the generalizability of its findings. First, the flavonoid levels of FFCL were not measured. Second, other oxidative stress biomarkers (e.g. superoxide dismutase) and inflammatory biomarkers (e.g. IL-6) were not investigated. Finally, the experiments were conducted on the model animals over a relatively short period of time. Further research is needed to evaluate the effect in humans at chronic use. Practical implications Chayote (Sechium edule (Jacq.) Sw) leaves are rich in flavonoids, especially apigenin and luteolin, which can improve oxidative stress and inflammation conditions caused by hyperuricemia. Social implications Hyperuricemia is a risk factor for non-communicable diseases, mostly caused by oxidative stress and inflammation in the body due to high levels of UA, one of the treatment strategies is through diet modification. Originality/value The results of this investigation imply that the administration of the flavonoid fraction of chayote leaves has significant effects on UA and oxidative stress and inflammatory markers. Further research is necessary to confirm the results.

First Report of Neoerysiphe sechii Causing Powdery Mildew on Sechium edule in San Luis Potosi, Mexico

From 2018 to 2020, powdery mildew-like signs and symptoms were observed on chayote (Sechium edule var. virens levis) in a commercial field located in Santa María del Río, San Luis Potosí, Mexico. Signs appeared as whitish powdery masses on both sides of leaves and stems. Disease incidence was about 30% and signs covered up to 70% of leaf surface. Ten samples were collected and analyzed. Mycelium was amphigenous, persistent, white, in dense patches. Hyphal appressoria were lobed and solitary. Conidiophores (n = 30) were hyaline, erect, straight, and 62 to 101 μm long. Foot cells were cylindrical and straight, followed by 1–3 shorter cells, and forming conidia in short chains. Conidia (n = 100) were hyaline, surface striate, cylindrical-ellipsoid, doliiform or ovoid, 25.7 to 37.6 × 11.9 to 18.4 μm, without fibrosin bodies, and with germ tubes terminal or subterminal. Conidial appressoria were lobed. Chasmothecia were not observed. The morphological characters were consistent with those of the anamorphic state of Neoerysiphe sechii (Gregorio-Cipriano et al. 2020). A voucher specimen was deposited in the Herbarium of the Department of Agricultural Parasitology at the Chapingo Autonomous University under accession number UACH192. To confirm the identification of the fungus, genomic DNA was extracted from conidia and mycelium, and the internal transcribed spacer (ITS) region and part of the 28S gene were amplified by PCR and sequenced. The ITS region of rDNA was amplified using the primers ITS5/ITS4 (White et al. 1990). For amplification of the 28S rRNA partial gene, a nested PCR was performed using the primer sets PM3 (Takamatsu and Kano 2001)/TW14 (Mori et al. 2000) and NL1/TW14 (Mori et al. 2000) for the first and second reactions, respectively. Phylogenetic analyses using the maximum parsimony and maximum likelihood methods, including ITS and 28S sequences of isolates of Neoerysiphe spp. were performed and confirmed the results obtained in the morphological analysis. The isolate UACH192 grouped in a clade with isolates of N. sechii. The ITS + 28S sequence was deposited in GenBank under accession number MZ468642. Pathogenicity was confirmed by gently dusting conidia from infected leaves onto ten leaves of healthy chayote plants. Five non-inoculated leaves served as controls. The plants were maintained in a greenhouse at 25 to 30 ºC, and relative humidity of 60 to 70%. All inoculated leaves developed similar symptoms to the original observation after 8 days, whereas control leaves remained disease free. Microscopic examination of the fungus on inoculated leaves showed that it was morphologically identical to that originally observed. The pathogenicity test was repeated twice with similar results. Based on morphological data and phylogenetic analysis, as well as pathogenicity test, the fungus was identified as N. sechii. This pathogen has been previously reported causing powdery mildew on S. edule and S. mexicanum in Veracruz, Mexico (Gregorio-Cipriano et al. 2020). However, to our knowledge, this is the first report of N. sechii causing powdery mildew on chayote in San Luis Potosí (Central Mexico). This pathogen represents a serious threat to chayote production and disease management strategies should be developed.