Valoración farmacéutica y nutricional de cepas de Ganoderma spp.

Abstract

Ganoderma spp. comprende varias especies de hongos reconocidos mundialmente por sus propiedades medicinales, como la estimulación física en situaciones de estrés, mejoras en el sistema inmunológico y la regulación del colesterol, siendo los polisacáridos y los terpenoides los principales compuestos bioactivos. La especie más conocida es G. lucidum, utilizada como remedio ancestral por más de 2000 años. En la última década, la comercialización de productos a base de Ganoderma y el mercado de suplementos dietarios con hongos medicinales ha experimentado mundialmente un aumento significativo, incluso en Argentina. Recientemente en Argentina se han introducido diversos productos basados en G. lucidum destinados a mejorar funciones vitales. Si bien esta especie ha sido incluida recientemente en el Código Alimentario Argentino dentro de los hongos comestibles, estos productos carecen aún de una regulación específica. La taxonomía del género Ganoderma es compleja, lo que dificulta su completo desarrollo como producto medicinal. Por esto, resulta necesario combinar métodos morfológicos, quimiotaxonómicos y moleculares para una correcta identificación. Esta tesis se propuso determinar los factores que influyen en la variabilidad de las propiedades medicinales y nutricionales de los suplementos alimentarios a base de Ganoderma spp. Además, se buscó establecer protocolos y procedimientos para controlar dichas variables, demostrar la seguridad y eficacia de los productos, y generar información necesaria para futuros estudios clínicos. Se cultivaron seis cepas de Ganoderma en el Laboratorio de Hongos Comestibles y Medicinales del CERZOS (Centro de Recursos Naturales Renovables de la Zona Semiárida CONICET/UNS), mediante fermentación en estado sólido. Cuatro de ellas mostraron un rendimiento prometedor de biomasa, y fueron identificadas taxonómicamente mediante métodos moleculares. Dos cepas fructificaron en sustrato sólido, mientras que las otras dos no pudieron obtenerse por este método, recurriéndose al cultivo líquido para obtener biomasa. Se realizaron análisis morfológicos, de vi antagonismo y de perfiles proteicos para confirmar la identidad de las cepas. También, se analizó la composición nutricional y la inocuidad alimentaria de los micelios y basidiomas. Las cepas identificadas fueron G. sessile, G. lingzhi, G. oregonense, y una perteneciente al género Phellinus. Se observaron diferencias en los rendimientos de biomasa y polisacáridos entre G. sessile y las otras especies en cultivo líquido. Este último método demostró ser más efectivo para la producción de polisacáridos en términos de duración y productividad. Las cepas se diferenciaron en el contenido de proteínas, carbohidratos y fibra dietaria total, mientras que todas mostraron un perfil de seguridad adecuado. Finalmente, se aislaron, purificaron y analizaron químicamente los polisacáridos del cultivo líquido de G. sessile. Se estudió su efecto en la microbiota intestinal de voluntarios sanos mediante fermentación in vitro, empleando un producto comercial a base de G. lucidum como comparador. G. sessile resultó contener heteropolisacáridos complejos, disímiles a los hallados en G. lucidum. Las diferencias químicas se acompañaron con efectos diferenciales in vitro, donde los polisacáridos de G. sessile incrementaron significativamente la producción de metabolitos antiinflamatorios en todos los casos estudiados. G. sessile, especie frecuentemente recolectada en América, mostró ser prometedora para la producción de polisacáridos bioactivos y la fabricación de suplementos dietarios.

Ganoderma spp. includes several fungal species known for their medicinal properties, including physical stimulation in stressful situations, immune system improvements, and cholesterol regulation, with polysaccharides and terpenoides being the most bioactive components. Ganoderma lucidum is the most well-known species, having been used as an ancient remedy for over 2000 years. In the last decade, the commercialization of Ganoderma products and the market for dietary supplements containing medicinal mushrooms has seen a significant increase worldwide, including Argentina. Several products based on G. lucidum have recently been introduced in Argentina with the goal of improving crucial health functions. Although this species has recently been included in the Argentine Food Code among edible mushrooms, these products still lack specific regulation. Ganoderma taxonomy is complex, which complicates its full development as a therapeutic product. The need of combining morphological, chemotaxonomic, and molecular methods for accurate identification has been emphasized. This thesis aimed to identify the factors that influence the variability of the medicinal and nutritional properties of Ganoderma spp.-based food supplements. Furthermore, it sought to establish protocols and procedures for controlling these variables, demonstrating product security and efficacy, and generating data for future clinical studies. Six Ganoderma strains were grown in the CERZOS Laboratory of Edible and Medicinal Fungi, by solid state fermentation. Four of these strains had promising biomass yield and were taxonomically identified using molecular methods. Two strains fructified in solid substrate, but the other two could not be obtained using this method, hence liquid cultivation was used to obtain biomass. Morphological, antagonism, and proteomic analyses were performed to confirm the identity of the strains. The nutritional composition and food safety of mycelia and basidiomes were also studied. Strains were identified as G. sessile, G. lingzhi, G. oregonense, and one of them showed to belong to the Phellinus genus. There were differences in biomass and polysaccharide yields between G. sessile and other liquid-cultured strains. The liquid culture proved to be more efficient in terms of time and productivity for the production of polysaccharides. The strains differed in their protein, carbohydrate, and total fiber content, yet all demonstrated an appropriate safety profile. Finally, polysaccharides from G. sessile liquid culture were isolated, purified, and chemically analyzed. The effect on the gut microbiota of healthy volunteers was studied using in vitro fermentation and a commercial product based on G. lucidum as a comparator. G. sessile had complex heteropolysaccharides, which were not found in G. lucidum. The chemical differences were accompanied by distinct in vitro effects, with G. sessile polysaccharides significantly increasing the production of antiinflammatory metabolites in all cases. G. sessile, a commonly collected species in America, has proven to be promising for the production of bioactive polysaccharides and the manufacture of dietary supplements. Strains were identified as G. sessile, G. lingzhi, G. oregonense, and one of them showed to belong to the Phellinus genus. There were differences in biomass and polysaccharide yields between G. sessile and other liquid-cultured strains. The liquid culture proved to be more efficient in terms of time and productivity for the production of polysaccharides. The strains differed in their protein, carbohydrate, and total fiber content, yet all demonstrated an appropriate safety profile. Finally, polysaccharides from G. sessile liquid culture were isolated, purified, and chemically analyzed. The effect on the gut microbiota of healthy volunteers was studied using in vitro fermentation and a commercial product based on G. lucidum as a comparator. G. sessile had complex heteropolysaccharides, which were not found in G. lucidum. The chemical differences were accompanied by distinct in vitro effects, with G. sessile polysaccharides significantly increasing the production of antiinflammatory metabolites in all cases. G. sessile, a commonly collected species in America, has proven to be promising for the production of bioactive polysaccharides and the manufacture of dietary supplements. Strains were identified as G. sessile, G. lingzhi, G. oregonense, and one of them showed to belong to the Phellinus genus. There were differences in biomass and polysaccharide yields between G. sessile and other liquid-cultured strains. The liquid culture proved to be more efficient in terms of time and productivity for the production of polysaccharides. The strains differed in their protein, carbohydrate, and total fiber content, yet all demonstrated an appropriate safety profile. Finally, polysaccharides from G. sessile liquid culture were isolated, purified, and chemically analyzed. The effect on the gut microbiota of healthy volunteers was studied using in vitro fermentation and a commercial product based on G. lucidum as a comparator. G. sessile had complex heteropolysaccharides, which were not found in G. lucidum. The chemical differences were accompanied by distinct in vitro effects, with G. sessile polysaccharides significantly increasing the production of antiinflammatory metabolites in all cases. G. sessile, a commonly collected species in America, has proven to be promising for the production of bioactive polysaccharides and the manufacture of dietary supplements.