Anti-Acanthamoeba castellanii activity of alkaloid-enriched extracts and lycorine from the Amaryllidaceae species

Abstract Free-living amoebae of the genus Acanthamoeba are the causative agents of granulomatous encephalitis and keratitis, severe human infections. Bioactive compounds from plants are recognized as an alternative source for the development of new drugs. The Amaryllidaceae is a botanical family able to synthesize a very specific and consistent group of biologically active isoquinoline-like alkaloids. The alkaloidal fractions from the Brazilian species Hippeastrum canastrense, H. diniz-cruziae, H. puniceum, and Crinum x amabile, along with the alkaloid lycorine, were investigated against Acanthamoeba castellanii. The in vitro assays were performed with distinct concentrations of lycorine and alkaloidal fractions, while the cell viability was evaluated by the MTT method upon MDCK cells. Chlorhexidine 0.02% was used as the positive control. The effect of alkaloid fractions was concentration dependent, and 2000 µg mL-1 of H. canastrense and H. diniz-cruziae provided a 100% inhibition. At concentrations of 250, 500, and 1000 µg mL-1, the H. diniz-cruziae alkaloidal fraction showed the lowest cytotoxic effect (5%-7%) and remarkable anti-amoebic activity, demonstrating values of IC50 285.61 µg mL-1, low cytotoxicity (5%-7%), and selectivity index (7.0). Taken together, the results are indicative of the great potential that the alkaloids from H. diniz-cruziae have as new candidates for anti-amoebicidal compounds

Biosíntesis y mejoramiento de la producción de alcaloides en la familia Amaryllidaceae / Review biosynthesis and enhancement of alkaloid production in the Amaryllidaceae family

INTRODUCCIÓN: la presente revisión bibliográfica referencia diversos estudios que describen la biosíntesis de alcaloides en la familia Amaryllidacea. Se toman en cuenta los procesos enzimáticos que rigen la biosíntesis de los metabolitos secundarios y los métodos de estimulación y mejoramiento de la producción de alcaloides. OBJETIVO: determinar, mediante una amplia revisión bibliográfica, los posibles métodos de mejora de la producción de alcaloides. METODOLOGÍA: se realizó una revisión bibliográfica de los documentos más relevantes sobre la biosíntesis de alcaloides de Amaryllidaceae. RESULTADOS: en esta revisión, es posible establecer una metodología de mejoramiento de la producción de alcaloides tipo crinina/haemantamina en plantas de la familia Amaryllidaceae nativas de Bolivia y evaluar la posibilidad de aplicarla con éxito para la obtención de mejores rendimientos.(AU)

INTRODUCTION: the referenced studies in this bibliographic review show the alkaloid biosynthesis in the Amaryllidaceae family. Some of the processes involved in the improvement and stimulation of alkaloid production are also taken into account and the enzymatic processes that rule secondary metabolites synthesis are described. OBJECTIVE: to determine, through a bibliographic review, possible methods of improving alkaloid production. METHODS: a wide bibliographic review of the most relevant articles about the Amaryllidaceae family alkaloid production was applied. RESULTS: it was possible to demonstrate that there is the possibility to stablish and develop a successful method to improve the production of crinine/haemanthamine type alkaloids in the Bolivian native family Amaryllidacea and to evaluate the possibility of applying it successfully to obtain better yields.(AU)

Chemical evaluation and anticholinesterase activity of Hippeastrum puniceum (Lam. ) Kuntz bulbs (Amaryllidaceae)

Hippeastrum puniceum is a species that belongs to the Amaryllidaceae family. A particular characteristic of this family is the consistent and very specific presence of isoquinoline alkaloids, which have demonstrated a wide range of biological activities such as antioxidant, antiviral, antifungal, antiparasitic, and acetylcholinesterase inhibitory activity, among others. In the present work, fifteen alkaloids were identified from the bulbs of Hippeastrum puniceum (Lam.) Kuntz using a GC-MS approach. The alkaloids 9-O-demethyllycoramine, 9-demethyl-2α-hydroxyhomolycorine, lycorine and tazettine were isolated through chromatographic techniques. The typical Amaryllidaceae alkaloids lycorine and tazettine, along with the crude and ethyl acetate extract from bulbs of the species were evaluated for their inhibitory potential on α-amylase, α-glucosidase, tyrosinase and acetylcholinesterase activity. Although no significant inhibition activity was observed against α-amylase, α-glucosidase and tyrosinase from the tested samples, the crude and ethyl acetate extracts showed remarkable acetylcholinesterase inhibitory activity. The biological activity results that correlated to the alkaloid chemical profile by GC-MS are discussed herein. Therefore, this study contributed to the knowledge of the chemical and biological properties of Hippeastrum puniceum (Lam.) and can subsidize future studies of this species

Non-alkaloid constituents of Hymenocallis littoralis / 中国中药杂志

Perennial herb Hymenocallis littoralis(Amaryllidaceae) boasts anti-tumor, anti-virus, and anti-inflammatory activities. As the representative constituents, alkaloids have attracted much attention, whereas the non-alkaloid constituents have been rarely reported. Therefore, this study investigated the non-alkaloid constituents of H. littoralis and their contribution to the various pharmacological activities of the herb. Thirteen non-alkaloid compounds were isolated from the 95% ethanol extract of dried whole plant of H. littoralis after a series of chromatographic separation steps and spectral analysis, and they were identified as 5,7-dihydroxy-6,8-dimethoxy-2-hydroxymethyl-4H-chromoen-4-one(1), undulatoside A(2),(2S)-7,4'-dihydroxyflavane(3), naringenin(4), 4',7-hydroxy-8-methylflavanone(5), 8-methylnaringenin(6), 8-demethylfarrerol(7), 6-methyl-aromadendrin(8), 4',5,7-trihydroxy-8-methylflavanone(9), syzalterin(10), 6-methylapigenin(11), isoliquiritigenin(12), and undatuside C(13) based on the spectroscopic data analysis. Among them, compound 1 was a new chromone derivative, and compounds 2 and 4-13 were isolated form this plant for the first time.

Antifungal activity of some Sternbergia taxa: effects on germ tube and biofilm formation

Natural products are rapidly becoming the primary sources of novel antimicrobial agents, as resistance to existing antimicrobial agents is increasing. Apart from determining the antimicrobial activity of natural products, it is also important to understand their effects on the virulence factors of microorganisms. This study aimed to determine the antimicrobial activity of Sternbergia species prevalent in Turkey and investigate their role in the inhibition of germination tube and biofilm formation, both of which are known to be important virulence factors of Candida albicans. The antimicrobial activities of the plant extracts were evaluated using bore-plate and broth microdilution method. The extracts' capacity to inhibit the formation of the germ-tube was also evaluated. The findings of our study revealed that Sternbergia lutea, Sternbergia vernalis possessed antimicrobial activities, with MIC values ranging between 0.048 mg/mL and 0.39 mg/mL. The highest antimicrobial activity was observed against Candida dubliniensis (0.048 mg/mL). While evaluating the inhibition of fungal germination activities, S. vernalis extract (at a concentration of 0.09 mg/mL) was found to be the most effective against C. albicans ATCC 90028 strain. The results also indicated that S. vernalis extracts at sub-MIC levels inhibited germ tube formation and modulated the tail-length of germinated cells, both of which are important virulence factors of C. albicans. Furthermore, the inhibition of biofilm-formation was also investigated, and it was found that two Sternbergia spp. extracts at or below MIC levels inhibited biofilm formation.

Application of HPLC-DAD for the quantification of Lycorine in Galanthus elwesii Hook

ABSTRACT In the present study, a reversed-phase high-performance liquid chromatographic method has been used for the quantitative determination of lycorine in the aerial parts and bulbs of G. elwesii Hook. A simple method for the extraction of lycorine in low mass plant samples was employed utilizing pre-packed columns with diatomaceous earth (Extrelut(r)). The chromatographic separation was performed using an isocratic system with a mobile phase of trifluoroacetic acid-water-acetonitrile (0.01:92.5:7.5, v/v/v) applied at a flow rate 1 mL min-1 using diode array detector. The content of lycorine in the bulbs and aerial parts of G. elwesii collected from Demirci (Manisa) was found as 0.130 and 0.162 %, respectively. Additionally, in the bulbs of the specimens collected from Sogucak (Balikesir), lycorine was quantified as 0.055 %, whereas in the aerial parts, it was determined as 0.006 %. The method was validated partially with respect to system specificity, linearity, accuracy, precision, limits of detection (LOD) and quantitation (LOQ). Validation procedures displayed that the method was specific, accurate and precise.