The state of the art of marine natural products in Colombia / El estado del arte de los productos naturales marinos en Colombia / O estado da arte dos produtos naturais marinhos na Colômbia

Abstract Marine Natural Products (MNPs) isolated from samples collected in Colombia have been an object of study since the early 1980's; however, this information is neither integrated nor compiled. This systematic review describes the articles published in scientific journals up to December 2019. 173 papers met the inclusion criteria of focusing on MNPs obtained from specimens collected from Colombian seas; all original papers written in English, Portuguese or Spanish. The selected papers were mostly authored by researchers from Colombian groups, with low interaction amongst themselves. 99.4% of the papers studied samples collected from the Caribbean Sea; 183 species were studied, mainly sponges and octocorals. In this study, 1,690 compounds (238 new ones) were reviewed, mainly diterpenes and sterol derivatives. Of the selected papers, 76.8% measured various biological activities, including antibiotic (34%) and anticancer (30%). These papers were published in 51 journals (74.6% were international). In conclusion, scientific work on natural marine products of Colombian origin has incremented over time. The most relevant opportunities to address and fill existing gaps comprise: exploring Pacific Ocean organisms and several of the misrepresented taxa; promoting strong interactions amongst the MNPs research groups, and accordingly with other areas of knowledge; and having the productive sector participate in MNPs research.

Resumen Los productos naturales marinos (PNM) aislados de muestras recolectadas en Colombia han sido estudiados desde principios de los años 1980, mas esta información no está integrada, ni recopilada. Esta revisión sistemática describe los artículos publicados hasta diciembre de 2019. 173 artículos cumplieron los criterios de inclusión de enfoque en PNM obtenidos de especímenes recolectados en mares colombianos; trabajos originales escritos en inglés, portugués o español. La mayoría de los artículos fueron escritos por investigadores de grupos colombianos, con poca interacción entre ellos. El 99,4% de los artículos estudiaban muestras recolectadas del mar Caribe. Se estudiaron 183 especies, especialmente esponjas y octocorales. Se identificaron 1690 compuestos (238 nuevos), principalmente diterpenos y derivados de esteroles. En el 76,8% de los artículos se midió alguna actividad biológica, principalmente antibiótica (34%) y anticancerígena (30%). Los artículos se publicaron en 51 revistas (74,6% internacionales). En conclusión, la investigación sobre los PNM de origen colombiano ha crecido con el tiempo. Algunas oportunidades para abordar las lagunas encontradas comprenden: explorar los organismos del océano Pacífico y los taxa poco estudiados; promover interacciones entre los grupos de investigación de los PNM y de otras áreas del conocimiento; e involucrar al sector productivo en la investigación de los PMN.

Resumo Os Produtos Naturais Marinhos (PNMs) isolados de amostras coletadas na Colômbia têm sido objeto de estudo desde a década de 1980; porém, esta informação não está integrada nem compilada. Esta revisão sistemática descreve os artigos publicados em revistas científicas até dezembro de 2019. 173 artigos atenderam aos critérios de inclusão de foco em PNMs obtidos de espécimes coletados em mares colombianos; artigos originais escritos em inglês, português ou espanhol. A maioria dos autores dos artigos eram pesquisadores de grupos colombianos, com baixa interação entre eles. 99,4% dos artigos estudavam amostras coletadas no Mar do Caribe. Foram estudadas 183 espécies, especialmente esponjas e octocorais. Nesta revisão, identificaram-se 1690 compostos (238 novos), principalmente diterpenos e derivados de esterol. 76,8% dos artigos mediram algumas atividades biológicas, incluindo antibiótica (34%) e anticancerígena (30%). Os artigos analisados foram publicados em 51 periódicos (74,6% internacionais). Em conclusão, o trabalho científico sobre PNM de origem colombiana cresceu ao longo do tempo. As oportunidades mais relevantes para preencher as lacunas existentes incluem: explorar organismos do Oceano Pacífico e os taxa pouco estudados; promover interação entre os grupos de pesquisa de PNMs e com grupos de outras áreas do conhecimento; e envolver o setor produtivo na pesquisa de PNMs.

Dolabellane diterpenes from the Caribbean soft corals Eunicea laciniata and Eunicea asperula and determination of their anti HSV-1 activity / Dolabellanos de los octocorales caribenos Eunicea laciniata y Eunicea asperula y determinación de su actividad anti VHS-1 / Dolabellanos dos octocorais caribenhos Eunicea laciniata e Eunicea asperula e determinação de sua atividade anti HSV-1

Abstract Dolabellane diterpenes have considerable antiviral activity, but most studies have been focused towards compounds isolated from Dictyota brown algae. Although soft corals are also a significant source of these diterpenes, their antiviral potential has not been studied in detail. With the aim of assessing the biological activity of marine sources, we evaluated the dolabellane content in the soft corals Eunicea laciniata and E. asperula collected in Santa Marta, Colombian Caribbean. Dolabellanes 1-6 were isolated from E. laciniata while compounds 2, 4 and 5 were isolated from E. asperula. All compounds were identified by NMR, GC-EIMS, optical rotation and comparison with previously reported dolabellanes. GC-EIMS analyses showed that dolabellatrienone (2) transforms into compounds 4 and 5 as oxidation products upon prolonged storage; however, those compounds were also naturally present in the extract of the studied organisms. Pure dolabellanes were tested in vitro in antiviral assays against HSV-1. Compound 6 inhibited virus replication in infected cells (73.7% of inhibition at 50 µM) without cytotoxic effect (CC50 = 95 9), showing similar activity to the positive control Acyclovir®. Thus, compound 6 is an interesting candidate for further studies of dolabellanes as antivirals.

Resumen Los dolabellanos son diterpenos con actividad antiviral, la mayor parte de los estudios se han realizado con compuestos aislados de algas pardas del genero Dictyota. Los corales blandos son también una importante fuente de dolabellanos, pero el potencial antiviral de estos ha sido muy poco estudiado. Se llevó a cabo el estudio químico de los dolabellanos presentes en los octocorales Eunicea laciniata y Eunicea asperula, recolectados en Santa Marta, Caribe colombiano. Los dolabellanos 1-6 fueron aislados del octocoral E. laciniata mientras que en E. asperula se encontraron los compuestos 2, 4 y 5. La elucidaci6n estructural se llev6 a cabo mediante RMN, espectrometría de masas, rotaci6n 6ptica y comparaci6n con reportes previos. El análisis por CG-EM evidenci6 que la dolabellatrienona (2) se puede transformar en los compuestos 4 y 5 como producto del almacenamiento prolongado, no obstante, tales compuestos también estuvieron presentes en los extractos de los organismos estudiados. El compuesto 6 inhibi6 la replicaci6n del VHS-1 (73,7% de inhibición en células infectadas a una concentraci6n de 50 µM) sin efecto citot6xico (CC50 = 959), mostrando una citotoxicidad similar al Aciclovir®, un control positivo, por lo cual es un candidato para la realizaci6n de estudios adicionales sobre el potencial antiviral de los dolabellanos.

Resumo Os dolabellanos são diterpenos que têm mostrado atividade antiviral, os estudos neste campo estão centrados nos compostos isolados de algas do gênero Dictyota. Os octocorais também são uma fonte importante de dolabellanos, mas não tem sido estudados. Foirealizado o estudo químico dos octocorais Eunicea laciniata e Eunicea asperula, coletados em Santa Marta, Caribe Colombiano. O estudo químico dos dois organismos permitiu o isolamento dos dolabellanos 1-6 de E. laciniata, enquanto que para E. aspérula foram identificados os compostos 2, 4 e 5. A elucidação estrutural foi realizada mediante RMN, espectrometria de massas, rotação óptica e comparação com os dados da literatura. A análise por GC-MS evidenciou que a dolabelatrienona (2) pode gerar os compostos 4 e 5 como produto de degradação, a partir de um armazenamento prolongado. No entanto, os compostos também estavam presentes nos extratos dos organismos estudados. O composto 6 mostrou uma citotoxicidade similar ao Aciclovir®, um controle positivo, numa porcentagem de inibição da replicação do HVS-1 (73,7% de inibição em células infectadas na concentração de 50 µM) sem efeito citotóxico (CC50 = 959), o quetorna esse composto um candidato para o desenvolvimento de antivirais.

Búsqueda de bacterias marinas como fuente de inhibidores de quorum sensing (IQS): primer estudio químico de Oceanobacillus profundus (RKHC-62B) / Screening of marine bacterial strains as source of quorum sensing inhibitors (QSI): first chemical study of Oceanobacillus profundus (RKHC-62B)

Antecedentes: Los productos naturales aislados de microorganismos marinos han demostrado tener un amplio rango de actividades biológicas incluyendo inhibidores de quorum sensing. Objetivos: Estudiamos quince cepas bacterianas del phylum Firmicutes aisladas del coral blando Antillogorgia elisabethae que fueron evaluadas como una nueva fuente sostenible de compuestos inhibidores de quorum sensing (IQS). Métodos: Se prepararon cultivos en cuatro medios diferentes y extraídos usando una resina no iónica. Todos los extractos fueron probados con el fin de establecer su actividad inhibitoria de quorum sensing (IQS) usando Chromobacterium violaceum ATCC 31532 como biosensor. Los extractos activos fueron fraccionados mediante cartuchos RP-18. Cada fracción fue evaluada mediante bioensayo y analizada por HPLC. Resultados: Las fracciones metanólicas de Jeotgalicoccus halophilus y Oceanobacillus profundus fueron las más activas, lo cual sugiere que los compuestos no polares pueden ser los responsables de esta actividad. Conclusiones: El estudio químico del extracto orgánico de O. profundus cultivado en medio LBS permitió aislar los compuestos tirosol (1) y acetato de tirosol (2) como los responsables de la actividad IQS.

Background: Natural products isolated from marine microorganisms have demonstrated a wide range of biological activities included quorum sensing inhibitors. Objectives: We study fifteen marine Firmicutes bacterial strains isolated from the Caribbean soft coral Antillogorgia elisabethae that were evaluated as a novel and sustainable source of quorum sensing inhibitor compounds. Methods: Cultures were made in four different culture media and further extracted using a non-ionic resin. All these extracts were tested in order to establish its quorum sensing inhibition (QSI) activity using Chromobacterium violaceum ATCC 31532. The active extracts were fractionated by RP-18 cartridge. Each fraction was tested and evaluated for its composition by HPLC-PDA. Results: Methanol fractions of Jeotgalicoccus halophilus and Oceanobacillus profundus were the most active ones, suggesting that non-polar compounds could be the responsible for the QSI activity of the bacterial extracts here tested. Conclusions: The chemical study of the organic extract of Oceanobacillus profundus cultured in LBS, yielded the compounds tyrosol (1) and tyrosol acetate (2) as responsible of QSI activity showed by the organic extract.

Comparative central effects of the aqueous leaf extract of two populations of Passiflora edulis

ABSTRACTPassiflora edulis Sims, Passifloraceae, has been used in Brazilian traditional folk medicine to the treatment of anxiety and insomnia. P. edulis is commonly known for its economic interests in Brazil. This species exhibits significant variability in the fruit rind color, then two subpopulations has been described (P. edulis fo. flavicarpa O. Deg. (PEF); P. edulis fo. edulis (PEE)). This study compared phytochemical profile and biological actions of aqueous leaf extract of PEE and PEF. HPLC analysis showed marked distinct chromatograms to the P. edulisvarieties. However, in both extracts the major compounds observed were flavonoids C-glycosides. Behavioral studies showed that PEE (300 mg/kg, p.o.) and PEF (100 and 300 mg/kg, p.o.) reduced anxiety in the elevated plus maze test. PEE (300 and 1000 mg/kg, p.o.) and PEF (1000 mg/kg, p.o.) also induced antidepressant-like actions in the forced swimming test. PEE 1000 mg/kg significantly reduced distance moved, thus suggesting sedation. No alterations in sleeping time were observed with PEE and PEF extracts. In conclusion, despite the similarities between the biological actions observed for both P. edulis varieties, quite different phytochemical profile was herein reported. These data suggest that the anxiolytic and antidepressant actions are not due to a specific phytochemical component.

Involvement of GABAergic pathway in the sedative activity of apigenin, the main flavonoid from Passiflora quadrangularis pericarp

Abstract In the current study we showed that oral administration of an aqueous extract of Passiflora quadrangularis L., Passifloraceae, pericarp results in a significant prolongation of the sleep duration in mice evaluated in the ethyl ether-induced hypnosis test which indicates sedative effects. Apigenin, the main flavonoid of the extract, induced a similar sedative response when applied alone, at a dose equivalent to that found in the extract, suggesting that apigenin is mediating the sedative effects of P. quadrangularis extract. In addition, the sedative effect of apigenin was blocked by pretreatment with the benzodiazepine antagonist flumazenil (1 mg/kg), suggesting an interaction of apigenin with gamma-aminobutyric acid type A (GABAA) receptors. However, apigenin at concentrations 0.1–50 µM failed to enhance GABA-induced currents through GABAA receptors (α1β2γ2S) expressed in Xenopus oocytes. Nevertheless, based on our results, we suggest that the in vivo sedative effect of the P. quadrangularis extract and its main flavonoid apigenin maybe be due to an enhancement of the GABAergic system.

Antiherpes screening of marine organisms from Colombian Caribbean Sea

The exploration of marine environment represents a promising strategy in the search for new active antiviral compounds. The isolation and characterization of the nucleosides spongothymidine and spongouridine from the sponge Cryptotethia crypta used as models for the synthesis of ara-A (vidarabine), that has been used therapeutically against herpetic encephalitis, was the most important contribution since the late 1970s. This paper describes the in vitro antiviral evaluation of 26 organic extracts obtained from eleven octocoral species and fifteen marine sponges. Cytotoxicity was evaluated on Vero cells by MTT assay and the antiviral activity was tested against Herpes Simplex Virus type 1 (HSV-1, KOS strain) by plaque number reduction assay. Results were expressed as 50 percent cytotoxic (CC50) and 50 percent inhibitory (IC50) concentrations, respectively, in order to calculate the selectivity index (SI= CC50/IC50) of each extract. Among the tested marine octocoral species, only three extracts showed antiviral activity, but with low selectivity indices (<3.0). Among the tested marine sponges, eight extracts showed SI values higher than 2.0, and three can be considered promising (Aka cachacrouense, Niphates erecta and Dragmacidon reticulatum) with SI values of 5.0, 8.0 and 11.7, respectively, meriting complementary studies in order to identify the bioactive components of these sponge extracts, which are in course now.